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Sample records for acid grafted chitosan

  1. Protocatechuic acid grafted onto chitosan: Characterization and antioxidant activity.

    PubMed

    Liu, Jun; Meng, Chen-Guang; Yan, Ye-Hua; Shan, Ya-Na; Kan, Juan; Jin, Chang-Hai

    2016-08-01

    In this study, protocatechuic acid (PA) was grafted onto chitosan (CS) by a carbodiimide mediated cross-linking reaction. The structural characterization, physical property and antioxidant activity of PA grafted CS (PA-g-CS) was investigated. As results, three copolymers with different grafting ratios (61.64, 190.11 and 279.69mg PAE/g) were obtained by varying the molar ratios of reaction substrates. PA-g-CS showed the same UV absorption peaks as PA at 258 and 292nm. As compared to CS, PA-g-CS exhibited a decreased band at 1596cm(-1) and a new band at 1716cm(-1), suggesting the formation of amide and ester linkages between PA and CS. New proton signals at δ6.77-7⋅33ppm were observed on (1)H NMR spectrum of PA-g-CS, assigning to the methine protons of PA. Signals at δ 150.8-116.6 ppm on (13)C NMR spectrum of PA-g-CS was assigned to the aromatic ring carbon of PA moieties. All the structural information confirmed the successful grafting of PA onto CS. SEM observation showed CS had a smooth surface, while PA-g-CS had a rough surface. TGA revealed the thermal stability of PA-g-CS was lower than CS. Antioxidant activity assays further verified the reducing power and DDPH radical scavenging activity of PA-g-CS was much higher than CS. PMID:27164501

  2. Hemocompatibility of Chitosan/poly(acrylic acid) Grafted Polyurethane Tubing

    PubMed Central

    Lee, Hyun-Su; Tomczyk, Nancy; Kandel, Judith; Composto, Russell J.; Eckmann, David M.

    2013-01-01

    The activation and adhesion of platelets or whole blood exposed to chitosan (CH) grafted surfaces is used to evaluate the hemocompatibility of biomaterials. The biomaterial surfaces are polyurethane (PU) tubes grafted with an inner poly(acrylic acid) (PAA) and an outer CH or quaternary ammonium modified CH (CH-Q) brush. The CH, CH-Q and PAA grafted layers were characterized by ellipsometry and fluorescence microscopy. Material wear tests demonstrate that CH (CH-Q) is stably grafted onto PU tubes upon exposure to saline solution for 7 days. Using quartz-crystal microbalances with dissipation (QCM-D), in-situ adsorption of blood plasma proteins on CH and CH-Q compared to a silicon oxide control was measured. The QCM-D results showed that the physically adsorbed plasma protein layer on CH-Q and CH surfaces is softer and more viscous than the protein layer on the SiO2 surface. The CH-Q layer thus has the weakest interaction with plasma proteins. Whole blood and platelet adhesion was reduced by ~92% on CH-Q, which showed the weakest interaction with plasma protein but more viscous adsorbed plasma protein layer, compared to SiO2. Last, to examine the biologic response of platelets and neutrophils to biomaterial surfaces, CH (CH-Q)/PAA, PAA and PU tubes were tested using a Chandler Loop apparatus as an ex vivo model and flow cytometry. The blood adhesion and biologic response results showed that CH and CH-Q reduced adhesion and activation of platelets and neutrophils and improved hemocompatibility relative to other surfaces (PU and PAA). Our studies demonstrated that the properties of physically adsorbed plasma protein layer on biomaterial surfaces correlates with blood coagulation on biomaterial surfaces. PMID:24349719

  3. Hemocompatibility of Chitosan/poly(acrylic acid) Grafted Polyurethane Tubing.

    PubMed

    Lee, Hyun-Su; Tomczyk, Nancy; Kandel, Judith; Composto, Russell J; Eckmann, David M

    2013-12-14

    The activation and adhesion of platelets or whole blood exposed to chitosan (CH) grafted surfaces is used to evaluate the hemocompatibility of biomaterials. The biomaterial surfaces are polyurethane (PU) tubes grafted with an inner poly(acrylic acid) (PAA) and an outer CH or quaternary ammonium modified CH (CH-Q) brush. The CH, CH-Q and PAA grafted layers were characterized by ellipsometry and fluorescence microscopy. Material wear tests demonstrate that CH (CH-Q) is stably grafted onto PU tubes upon exposure to saline solution for 7 days. Using quartz-crystal microbalances with dissipation (QCM-D), in-situ adsorption of blood plasma proteins on CH and CH-Q compared to a silicon oxide control was measured. The QCM-D results showed that the physically adsorbed plasma protein layer on CH-Q and CH surfaces is softer and more viscous than the protein layer on the SiO2 surface. The CH-Q layer thus has the weakest interaction with plasma proteins. Whole blood and platelet adhesion was reduced by ~92% on CH-Q, which showed the weakest interaction with plasma protein but more viscous adsorbed plasma protein layer, compared to SiO2. Last, to examine the biologic response of platelets and neutrophils to biomaterial surfaces, CH (CH-Q)/PAA, PAA and PU tubes were tested using a Chandler Loop apparatus as an ex vivo model and flow cytometry. The blood adhesion and biologic response results showed that CH and CH-Q reduced adhesion and activation of platelets and neutrophils and improved hemocompatibility relative to other surfaces (PU and PAA). Our studies demonstrated that the properties of physically adsorbed plasma protein layer on biomaterial surfaces correlates with blood coagulation on biomaterial surfaces. PMID:24349719

  4. Chitosan grafted monomethyl fumaric acid as a potential food preservative.

    PubMed

    Khan, Imran; Ullah, Shafi; Oh, Deog-Hwan

    2016-11-01

    The present study aims at in vitro antibacterial and antioxidant activity evaluation of chitosan modified with monomethyl fumaric acid (MFA) using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) as mediator. Three different kinds of chitosan derivatives Ch-Ds-1,Ch-Ds-2 and Ch-Ds-3 were synthesized by feeding different concentration of MFA. The chemical structures of resulting materials were characterized by (1)H NMR, (13)C NMR, HR-XRD, FT-IR and TNBS assay. The results showed that Ch-Ds-1, Ch-Ds-2 and Ch-Ds-3 were successfully synthesized. The % amino groups of chitosan modified by MFA were evaluated by TNBS assay and ranging from 1.82±0.05% to 7.88±0.04%. All the chitosan derivatives are readily soluble in water and swelled by dimethyl sulfoxide (DMSO), toluene and dimethyl formamide (DMF). The antioxidant activity for all the chitosan derivatives have been significantly improved (P<0.05) compared to the chitosan. Upon antibacterial activity at pH 4.0, all the chitosan derivatives showed significant (P<0.05) antibacterial activity against Gram positive Staphylococcus aureus, Listeria monocytogenes strains and Gram negative Escherichia coli and Salmonella enteritidis strains compared to chitosan. In conclusion, MFA modified chitosan has shown enhanced activities along with solubility, and could be used as a novel food preservative and packaging material for long time food safety and security. PMID:27516253

  5. Preparation, characterization and antioxidant activity of phenolic acids grafted carboxymethyl chitosan.

    PubMed

    Liu, Jun; Lu, Jian-feng; Kan, Juan; Tang, Ying-qing; Jin, Chang-hai

    2013-11-01

    In this study, three phenolic acids including gallic acid (GA), caffeic acid (CA) and ferulic acid (FA) were grafted onto N,O-carboxymethyl chitosan (NOCC) by a free radical mediated grafting method. The grafted copolymers obtained were all water-soluble samples. UV-vis absorption peaks of the grafted copolymers shifted toward longer wavelengths. FT-IR spectroscopy of the grafted copolymers exhibited additional phenolic characteristics of the aromatic ring CC stretching within 1450-1650 cm(-1). NMR spectroscopy of the grafted copolymers showed new peaks at 6.2-7.6 ppm assigned to the phenyl protons of phenolic acids. These results all confirmed the successful grafting of three phenolic acids to NOCC. The conjugation probably occurred at amine of NOCC and carboxyl groups of phenolic acids. The grafted copolymers exhibited decreased crystallinity as compared to NOCC and chitosan. Moreover, antioxidant activity in vitro assays showed that the antioxidant property decreased in the order of GA-g-NOCC>CA-g-NOCC>FA-g-NOCC>NOCC>chitosan. Our results suggested the potential of phenolic acids grafted NOCC for the development of effective antioxidant agents. PMID:23994782

  6. Development of thiamine and pyridoxine loaded ferulic acid-grafted chitosan microspheres for dietary supplementation.

    PubMed

    Chatterjee, Niladri Sekhar; Anandan, Rangasamy; Navitha, Mary; Asha, K K; Kumar, K Ashok; Mathew, Suseela; Ravishankar, C N

    2016-01-01

    Therapeutic potential of water soluble vitamins has been known for long and in recent times they are being widely supplemented in processed food. Phenolic acid-grafted chitosan derivatives can serve as excellent biofunctional encapsulating materials for these vitamins. As a proof of concept, thiamine and pyridoxine loaded ferulic acid-grafted chitosan microspheres were developed. Ferulic acid was successfully grafted on chitosan by a free radical mediated reaction and the structure was confirmed by FTIR and NMR analysis. When compared to FTIR spectra of chitosan, intensity of amide I (at around 1644 cm(-1)) and amide II (at around 1549 cm(-1)) bands in spectra of ferulic acid-grafted chitosan were found increased, indicating formation of new amide linkage. Strong signals at δ = 6.3-7.9 ppm corresponding to methine protons of ferulic acid were observed in NMR spectra of ferulic acid-grafted chitosan, suggesting the successful grafting of ferulic acid onto chitosan. Grafting ratio of the derivative was 263 mg ferulic acid equivalent/g polymer. Positively charged particles (zeta potential 31 mv) of mean diameter 4.5 and 4.8 μ, corresponding to number distribution and area distribution respectively were observed. Compact microspheres with smooth surfaces and no apparent cracks or pores were observed under scanning electron microscope. Efficient microencapsulation was further proved by X-ray diffraction patterns and thermal analysis. Preliminary anti-inflammatory activity of the vitamin-loaded microspheres was demonstrated. PMID:26787974

  7. The effect of solvent composition on grafting gallic acid onto chitosan via carbodiimide.

    PubMed

    Guo, Ping; Anderson, John D; Bozell, Joseph J; Zivanovic, Svetlana

    2016-04-20

    The primary antioxidant (AOX) activity of chitosan can be introduced by grafting of phenolic compound - gallic acid (GA) to its amino and/or hydroxyl groups. The objective of this study was to investigate the effect of ethanol (EtOH) concentration (0%, 25%, 50%, and 75% in water) on efficiency of grafting GA onto chitosan in the presence of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC)/N-hydroxysuccinimide (NHS). The grafting was confirmed by FTIR and the efficiency was quantified as Folin's total phenolics. When pure deionized water was used as a sole solvent (0% EtOH), GA was grafted to chitosan at the largest extent (285.9mg GA/g chitosan). As the concentration of EtOH increased, the grafting efficiency proportionally decreased. NMR studies showed that EtOH inhibited grafting of GA by prohibiting the production of the intermediate - NHS ester. The results confirm that the concentration of EtOH in grafting solution significantly affects grafting efficiency of GA on chitosan. PMID:26876841

  8. Chemical modification of chitosan film via surface grafting of citric acid molecular to promote the biomineralization

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Shen, Xin; Zhou, Huan; Wang, Yingjun; Deng, Linhong

    2016-05-01

    We develop a novel chitosan-citric acid film (abbreviated as CS-CA) suitable for biomedical applications in this study. In this CS-CA film, the citric acid, which is a harmless organic acid has been extensively investigated as a modifying agent on carbohydrate polymers, was cross-linked by 1-Ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) onto the surface of chitosan (CS) film. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) confirms the graft copolymerization of the modified chitosan film (CS-CA). Surface wettability, moisturizing performance, the capacity of mineralization in vitro and biocompatibility of the films were characterized. After modification, this CS-CA film has good hydrophilicity. It is very evident that the citric acid grafting treatment significantly promotes the biomineralization of the chitosan based substrates. Cell experiments show that the MC3T3-E1 osteoblasts can adhere and proliferate well on the surface of CS-CA film. This CS-CA film, which can be prepared in large quantities and at low cost, should have potential application in bone tissue engineering.

  9. Oleic acid-grafted chitosan/graphene oxide composite coating for corrosion protection of carbon steel.

    PubMed

    Fayyad, Eman M; Sadasivuni, Kishor Kumar; Ponnamma, Deepalekshmi; Al-Maadeed, Mariam Al Ali

    2016-10-20

    An anticorrosion coating film based on the formation of nanocomposite coating is reported in this study. The composite consisted of chitosan (green matrix), oleic acid, and graphene oxide (nano filler). The nanocomposite coating was arranged on the surface of carbon steel, and the corrosion resistance was monitored using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP). Compared to the pure chitosan (CS) coating, the corrosion resistance of oleic acid-modified chitosan/graphene oxide film (CS/GO-OA) is increased by 100 folds. Since the well-dispersed smart grafted nanolayers delayed the penetration rate of corrosive species and thus maintained long term anticorrosive stability which is correlated with hydrophobicity and permeability. PMID:27474635

  10. In Vitro Antioxidant-Activity Evaluation of Gallic-Acid-Grafted Chitosan Conjugate Synthesized by Free-Radical-Induced Grafting Method.

    PubMed

    Hu, Qiaobin; Wang, Taoran; Zhou, Mingyong; Xue, Jingyi; Luo, Yangchao

    2016-07-27

    The major objective of this work was to develop a green and facile process to prepare gallic acid-chitosan conjugate and comprehensively evaluate the physicochemical properties and biological activities of an as-prepared water-soluble chitosan derivative. A free-radical-induced grafting approach using an ascorbic acid-hydrogen peroxide redox pair was adopted. The obtained conjugate was characterized by Fourier transform infrared spectroscopy, UV-vis, X-ray diffraction, and pKa analysis. The antioxidant activities were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6)-sulphonic acid (ABTS), reducing power, and oxygen-radical antioxidant-capacity assays. The results showed that the mass ratio of gallic acid to chitosan played a vital role in determining the grafting degree and ζ potential of the conjugates, with the ratio of 0.5:1 being the optimal ratio that resulted in the highest grafting degree. The antioxidant assays demonstrated that conjugation significantly improved the antioxidant activities, being dramatically higher than that of free chitosan. It was notable that the DPPH- and ABTS-scavenging activities of conjugate at 0.4 mg/mL reached the same level as the free gallic acid at the equivalent concentration. Our study demonstrated a green and facile synthesis approach to preparing a novel water-soluble chitosan derivative that may have promising potentials in the food industry. PMID:27379913

  11. Acidic pH resistance of grafted chitosan on dental implant.

    PubMed

    Campos, Doris M; Toury, Bérengère; D'Almeida, Mélanie; Attik, Ghania N; Ferrand, Alice; Renoud, Pauline; Grosgogeat, Brigitte

    2015-05-01

    Over the last decade, access to dental care has increasingly become a service requested by the population, especially in the case of dental implants. However, the major cause of implant failure is an inflammatory disease: peri-implantitis. Currently, the adhesion strength of antibacterial coatings at implant surfaces remains a problem to solve. In order to propose a functionalized implant with a resistant antibacterial coating, a novel method of chitosan immobilization at implant surface has been investigated. Functionalization of the pre-active titanium (Ti) surface was performed using triethoxysilylpropyl succinic anhydride (TESPSA) as a coupling agent which forms a stable double peptide bond with chitosan. The chitosan presence and the chemical resistibility of the coating under acid pH solutions (pH 5 and pH 3) were confirmed by FTIR-ATR and XPS analyses. Furthermore, peel test results showed high adhesive resistance of the TESPSA/chitosan coating at the substrate. Cytocompatibility was evaluated by cell morphology with confocal imaging. Images showed healthy morphology of human gingival fibroblasts (HGF-1). Finally, the reported method for chitosan immobilization on Ti surface via peptide bindings allows for the improvement of its adhesive capacities and resistibility while maintaining its cytocompatibility. Surface functionalization using the TESPSA/chitosan coupling method is noncytotoxic and stable even in drastic environments as found in oral cavity, thus making it a valuable candidate for clinical implantology applications. PMID:24972881

  12. Ligand-functionalized degradable polyplexes formed by cationic poly(aspartic acid)-grafted chitosan-cyclodextrin conjugates.

    PubMed

    Song, Hai-Qing; Li, Rui-Quan; Duan, Shun; Yu, Bingran; Zhao, Hong; Chen, Da-Fu; Xu, Fu-Jian

    2015-03-19

    Polypeptide-based degradable polyplexes attracted considerable attention in drug delivery systems. Polysaccharides including cyclodextrin (CD), dextran, and chitosan (CS) were readily grafted with cationic poly(aspartic acid)s (PAsps). To further enhance the transfection performances of PAsp-based polyplexes, herein, different types of ligand (folic acid, FA)-functionalized degradable polyplexes were proposed based on the PAsp-grafted chitosan-cyclodextrin conjugate (CCPE), where multiple β-CDs were tied on a CS chain. The FA-functionalized CCPE (i.e., CCPE-FA) was obtained via a host-guest interaction between the CD units of CCPE and the adamantane (Ad) species of Ad-modified FA (Ad-FA). The resulting CCPE/pDNA, CCPE-FA/pDNA, and ternary CCPE-FA/CCPE/pDNA (prepared by layer-by-layer assembly) polyplexes were investigated in detail using different cell lines. The CCPE-based polyplexes displayed much higher transfection efficiencies than the CS-based polyplexes reported earlier by us. The ternary polyplexes of CCPE-FA/CCPE/pDNA produced excellent gene transfection abilities in the folate receptor (FR)-positive tumor cells. This work would provide a promising means to produce highly efficient polyplexes for future gene therapy applications. PMID:25758351

  13. Bioactive and metal uptake studies of carboxymethyl chitosan-graft-D-glucuronic acid membranes for tissue engineering and environmental applications.

    PubMed

    Jayakumar, R; Rajkumar, M; Freitas, H; Sudheesh Kumar, P T; Nair, S V; Furuike, T; Tamura, H

    2009-08-01

    Carboxymethyl chitosan-graft-D-glucuronic acid (CMCS-g-D-GA) was prepared by grafting D-GA onto CMCS in the presence of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and then the membranes were made from it. In this work, the bioactivity studies of CMCS-g-D-GA membranes were carried out and then characterized by SEM, CLSM, XRD and FT-IR. The CMCS-g-D-GA membranes were found to be bioactive. The adsorption of Ni2+, Zn2+ and Cu2+ ions onto CMCS-g-D-GA membranes has also been investigated. The maximum adsorption capacity of CMCS-g-D-GA for Ni2+, Zn2+ and Cu2+ was found to be 57, 56.4 and 70.2 mg/g, respectively. Hence, these membranes were useful for tissue engineering, environmental and water purification applications. PMID:19409415

  14. Removal of reactive dyes from textile wastewater by immobilized chitosan upon grafted Jute fibers with acrylic acid by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Hassan, Mahmoud S.

    2015-10-01

    Jute fibers were grafted with acrylic acid by gamma irradiation technique. Chitosan was immobilized upon the grafted Jute fibers to be used as an adsorbent for waste reactive dye. The treated Jute fibers were characterized by using of Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effect of Jute treatment on its thermal stability by using thermogravimetric analysis (TGA) and its mechanical properties were investigated. The adsorption isotherm and the different factors affecting the dye adsorption such as pH and contact time were also studied. It was found that the dye adsorption was enhanced in the low pH range and increased with increasing of the contact time, regardless of temperature change.

  15. Schiff base - Chitosan grafted L-monoguluronic acid as a novel solid-phase adsorbent for removal of congo red.

    PubMed

    Yuan, Bo; Qiu, Li-Gan; Su, Hong-Zhen; Cao, Cheng-Liang; Jiang, Ji-Hong

    2016-01-01

    A novel modified chitosan adsorbent (GL-SBCS) was synthesized by covalently grafting a Schiff base-chitosan (SBCS) onto the surface of l-monoguluronic acid. Physico-chemical investigation on the adsorption of congo red, an anionic azo dye by GL-SBCS has been carried out. The effect of different weight contents of chitosan in GL-SBCS composite, adsorbent dosage, initial pH and contract time were studied in detail using batch adsorption. Results showed that GL-SBCS exhibited better than normal CS and l-monoguluronic acid. Further investigation demonstrated that the adsorption pattern fitted well with the Langmuir model (R(2)>0.99) but less-satisfied the Freundlich model. Both ionic interaction as well as physical forces is responsible for binding of congo red with GL-SBCS as determined by zeta potential measurement Both sodium chloride and sodium dodecyl sulfate significantly influenced the adsorption process. SBCS would be a good method and resource to increase absorption efficiency for the removal of anionic dyes in a wastewater treatment process. PMID:26432372

  16. Superabsorbent hydrogels via graft polymerization of acrylic acid from chitosan-cellulose hybrid and their potential in controlled release of soil nutrients.

    PubMed

    Essawy, Hisham A; Ghazy, Mohamed B M; El-Hai, Farag Abd; Mohamed, Magdy F

    2016-08-01

    Superabsorbent polymers fabricated via grafting polymerization of acrylic acid from chitosan (CTS) yields materials that suffer from poor mechanical strength. Hybridization of chitosan with cellulose (Cell) via chemical bonding using thiourea formaldehyde resin increases the flexibility of the produced hybrid (CTS/Cell). The hybridization process and post graft polymerization of acrylic acid was followed using Fourier transform infrared (FTIR). Also, the obtained structures were homogeneous and exhibited uniform surface as could be shown from imaging with scanning electron microscopy (SEM). Thus, the polymers derived from the grafting of polyacrylic acid from (CTS/Cell) gave rise to much more mechanically robust structures ((CTS/Cell)-g-PAA) that bear wide range of pH response due to presence of chitosan and polyacrylic acid in one homogeneous entity. Additionally, the obtained structures possessed greater water absorbency 390, 39.5g/g in distilled water and saline (0.9wt.% NaCl solution), respectively, and enhanced retention potential even at elevated temperatures as revealed by thermogravimetric analysis (TGA). This could be explained by the high grafting efficiency (GE%), 86.4%, and grafting yield (GY%), 750%. The new superabsorbent polymers proved to be very efficient devices for controlled release of fertilizers into the soil which expands their use in agriculture and horticultural applications. PMID:27126169

  17. Ligand-functionalized degradable polyplexes formed by cationic poly(aspartic acid)-grafted chitosan-cyclodextrin conjugates

    NASA Astrophysics Data System (ADS)

    Song, Hai-Qing; Li, Rui-Quan; Duan, Shun; Yu, Bingran; Zhao, Hong; Chen, Da-Fu; Xu, Fu-Jian

    2015-03-01

    Polypeptide-based degradable polyplexes attracted considerable attention in drug delivery systems. Polysaccharides including cyclodextrin (CD), dextran, and chitosan (CS) were readily grafted with cationic poly(aspartic acid)s (PAsps). To further enhance the transfection performances of PAsp-based polyplexes, herein, different types of ligand (folic acid, FA)-functionalized degradable polyplexes were proposed based on the PAsp-grafted chitosan-cyclodextrin conjugate (CCPE), where multiple β-CDs were tied on a CS chain. The FA-functionalized CCPE (i.e., CCPE-FA) was obtained via a host-guest interaction between the CD units of CCPE and the adamantane (Ad) species of Ad-modified FA (Ad-FA). The resulting CCPE/pDNA, CCPE-FA/pDNA, and ternary CCPE-FA/CCPE/pDNA (prepared by layer-by-layer assembly) polyplexes were investigated in detail using different cell lines. The CCPE-based polyplexes displayed much higher transfection efficiencies than the CS-based polyplexes reported earlier by us. The ternary polyplexes of CCPE-FA/CCPE/pDNA produced excellent gene transfection abilities in the folate receptor (FR)-positive tumor cells. This work would provide a promising means to produce highly efficient polyplexes for future gene therapy applications.Polypeptide-based degradable polyplexes attracted considerable attention in drug delivery systems. Polysaccharides including cyclodextrin (CD), dextran, and chitosan (CS) were readily grafted with cationic poly(aspartic acid)s (PAsps). To further enhance the transfection performances of PAsp-based polyplexes, herein, different types of ligand (folic acid, FA)-functionalized degradable polyplexes were proposed based on the PAsp-grafted chitosan-cyclodextrin conjugate (CCPE), where multiple β-CDs were tied on a CS chain. The FA-functionalized CCPE (i.e., CCPE-FA) was obtained via a host-guest interaction between the CD units of CCPE and the adamantane (Ad) species of Ad-modified FA (Ad-FA). The resulting CCPE/pDNA, CCPE

  18. Synthesis and evaluation of chitosan-graft-poly (2-hydroxyethyl methacrylate-co-itaconic acid) as a drug carrier for controlled release of tramadol hydrochloride

    PubMed Central

    Subramanian, Kaliappa gounder; Vijayakumar, Vediappan

    2011-01-01

    Chitosan-graft-poly (2-hydroxyethyl methacrylate-co-itaconic acid) has been synthesized for different feed ratios of 2-hydroxyethyl methacrylate and itaconic acid and characterized by FT-IR, thermogravimetry and swelling in simulated biological fluids (SBF) and evaluated as a drug carrier with model drug, tramadol hydrochloride (TRM). Grafting decreased the thermal stability of chitosan. FT-IR spectra of tablet did not reveal any molecular level (i.e. at <10 nm scale) drug–polymer interaction. But differential scanning calorimetric studies indicated a probable drug–polymer interaction at a scale >100 nm level. The observed Korsmeyer–Peppas’s power law exponents (0.19–1.21) for the in vitro release profiles of TRM in SBF and other drugs such as 5-fluorouracil (FU), paracetamol (PCM) and vanlafaxine hydrochloride (VNF) with the copolymer carriers revealed an anomalous drug release mechanism. The decreased release rates for the grafted chitosan and the enhanced release rate for the grafts with increasing itaconic acid content in the feed were more likely attributed to the enhanced drug–matrix interaction and polymer–SBF interactions, respectively. The different release profiles of FU, PCM, TRM and VNF with the copolymer matrix are attributed to the different chemical structures of drugs. The above features suggest the graft copolymer’s candidature for use as a promising oral drug delivery system. PMID:23960799

  19. Synthesis, biocompatible, and self-assembly properties of poly (ethylene glycol)/lactobionic acid-grafted chitosan.

    PubMed

    Song, Xiaoli; Wang, Juan; Luo, Xiadan; Xu, Chunlan; Zhu, Aiping; Guo, Rong; Yan, Caifeng; Zhu, Peizhi

    2014-07-01

    Polymers with targeted ligands are widely used as the anti-cancer drug delivery materials. For applications of chitosan as an anti-liver cancer drug delivery, poly (ethylene glycol)/lactobionic acid-grafted chitosan (PEG/LA-CS) was prepared and investigated since lactobionic acid can be specifically recognized by the hepatocytes. The structure of the PEG/LA-CS was characterized by Fourier transform infrared spectrometry and elemental analysis. The self-assembly behaviors of the PEG/LA-CS were monitored by steady-state fluorescence spectroscopy and electronic transmission microscope. The protein adsorption of the PEG/LA-CS was detected with bovine serum albumin (BSA) by electrochemical impedance spectroscopy. The results showed that the PEG/LA-CS almost did not adsorb protein. To study the effects of PEG/LA-CS on the structure of BSA, the interactions between the PEG/LA-CS and BSA were detected by ultraviolet spectrum, fluorescence spectrum, and circular dichroism. All the data gave one result that BSA maintained its original folded confirmation in PEG/LA-CS solution. The hemocompatibility of PEG/LA-CS was investigated by observing the effects of PEG/LA-CS on the hemolysis rate and the plasma recalcification time (PRT). The results showed that the PRT was prolonged greatly and the hemolysis rate was less than 5%. Furthermore, PEG/LA-CS also showed good cytocompatibility with K562, Hep G2, and LO2 cells. Therefore, the PEG/LA-CS is believed to have great potential for producing injectable anti-liver cancer drug delivery. PMID:24847798

  20. Antibacterial and synergic effects of gallic acid-grafted-chitosan with β-lactams against methicillin-resistant Staphylococcus aureus (MRSA).

    PubMed

    Lee, Dae-Sung; Eom, Sung-Hwan; Kim, Young-Mog; Kim, Hye Seon; Yim, Mi-Jin; Lee, Sang-Hoon; Kim, Do-Hyung; Je, Jae-Young

    2014-10-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is spreading worldwide, emphasizing the need to search for new antibiotics. The anti-MRSA activities of gallic acid-grafted-chitosans (GA-g-chitosans) were investigated against 2 MRSA standards and 10 MRSA clinical isolates by determining the minimum inhibitory concentrations (MICs). GA-g-chitosan (I), which has the highest gallic acid content, exhibited the strongest anti-MRSA activities, with MICs of 32-64 μg/mL. A time-kill investigation revealed that GA-g-chitosan (I) exhibited a bactericidal effect at twice the MIC, also demonstrating good thermal and pH stability. Investigation of cell envelope integrity showed the release of intracellular components with an increasing absorbance value at 260 nm, indicating cell envelope damage caused by the GA-g-chitosan (I), which was further confirmed by transmission electron microscopy. When GA-g-chitosans were combined with β-lactams, including ampicillin and penicillin, synergistic effects were observed on the 2 standard MRSA strains and on the 10 clinical isolates, with fractional inhibitory indices ranging from 0.125 to 0.625. In the time-kill dynamic confirmation test, synergistic bactericidal effects were observed for the combinations of GA-g-chitosans with β-lactams, and over 4.0 log CFU/mL reductions were observed after 24 h when combination treatment was used. These results may prove GA-g-chitosans to be a potent agent when combined with ampicillin and penicillin for the elimination of MRSA. PMID:25216286

  1. Ligand-directed stearic acid grafted chitosan micelles to increase therapeutic efficacy in hepatic cancer.

    PubMed

    Yang, Yuan; Yuan, Sheng-Xian; Zhao, Ling-Hao; Wang, Chao; Ni, Jun-Sheng; Wang, Zhen-Guang; Lin, Chuan; Wu, Meng-Chao; Zhou, Wei-Ping

    2015-02-01

    Targeted delivery system would be an interesting platform to enhance the therapeutic effect and to reduce the side effects of anticancer drugs. In this study, we have developed lactobionic acid (LA)-modified chitosan-stearic acid (CS-SA) (CSS-LA) to deliver doxorubicin (DOX) to hepatic cancer cells. The average particle size of CSS-LA/DOX was ∼100 nm with a high entrapment efficiency of >95%. Drug release studies showed that DOX release from pH-sensitive micelles is significantly faster at pH 5.0 than at pH 7.4. The LA conjugated micelles showed enhanced cellular uptake in HepG2 and BEL-7402 liver cancer cells than free drug and unconjugated micelles. Consistently, CSS-LA/DOX showed enhanced cell cytotoxicity in these two cell lines. Annexin-V/FITC and PI based apoptosis assay showed that the number of living cells greatly reduced in this group with marked presence of necrotic and apoptotic cells. LA-conjugated carrier induced typical chromatic condensation of cells; membrane blebbing and apoptotic bodies began to appear. In vivo, CSS-LA/DOX showed an excellent tumor regression profile with no toxic side effects. The active targeting moiety, long circulation profile, and EPR effect contributed to its superior anticancer effect in HepG2 based tumor. Our results showed that polymeric micelles conjugated with LA increased the therapeutic availability of DOX in the liver cancer cell based solid tumor without any toxic side effects. The active targeting ligand conjugated nanoparticulate system could be a promising therapeutic strategy in the treatment of hepatic cancers. PMID:25495890

  2. Fluorescent Bioactive Corrole Grafted-Chitosan Films.

    PubMed

    Barata, Joana F B; Pinto, Ricardo J B; Vaz Serra, Vanda I R C; Silvestre, Armando J D; Trindade, Tito; Neves, Maria Graça P M S; Cavaleiro, José A S; Daina, Sara; Sadocco, Patrizia; Freire, Carmen S R

    2016-04-11

    Transparent corrole grafted-chitosan films were prepared by chemical modification of chitosan with a corrole macrocycle, namely, 5,10,15-tris(pentafluorophenyl)corrole (TPFC), followed by solvent casting. The obtained films were characterized in terms of absorption spectra (UV-vis), FLIM (fluorescence lifetime imaging microscopy), structure (FTIR, XPS), thermal stability (TGA), thermomechanical properties (DMA), and antibacterial activity. The results showed that the chemical grafting of chitosan with corrole units did not affect its film-forming ability and that the grafting yield increased with the reaction time. The obtained transparent films presented fluorescence which increases with the amount of grafted corrole units. Additionally, all films showed bacteriostatic effect against S. aureus, as well as good thermomechanical properties and thermal stability. Considering these features, promising applications may be envisaged for these corrole-chitosan films, such as biosensors, bioimaging agents, and bioactive optical devices. PMID:26899016

  3. Effect of proteins with different isoelectric points on the gene transfection efficiency mediated by stearic acid grafted chitosan oligosaccharide micelles.

    PubMed

    Yan, Jingjing; Du, Yong-Zhong; Chen, Feng-Ying; You, Jian; Yuan, Hong; Hu, Fu-Qiang

    2013-07-01

    A stearic acid-grafted chitosan oligosaccharide (CS-SA) micelle has been demonstrated as an effective gene carrier in vitro and in vivo. Although being advantageous for DNA package, protection, and excellent cellular internalization, a CS-SA based delivery system may lead to difficulties in the dissociation of polymer/DNA complexes in intracells. In this research, bovine serum albumin (BSA) with a different isoelectric point value (4.7, 6.0 and 9.3) was synthesized and incorporated into a CS-SA based gene delivery system. CS-SA/DNA binary complexes and CS-SA/BSA/DNA ternary complexes were then prepared and characterized. The binding ability of the CS-SA vector with DNA was not affected by the incorporation of BSA. However, referring to the transfection activity, the BSA of different isoelectric point value (pI) had a distinct influence on the CS-SA/BSA/DNA complexes. CS-SA/BSA(4.7)/DNA and CS-SA/BSA(6.0)/DNA complexes had better transfection efficiency than binary complexes, especially CS-SA/BSA(4.7)/DNA complexes which showed the highest transfection efficiency. On the contrary, CS-SA/BSA(9.3)/DNA complexes had undesirable performances. Interestingly, the incorporation of BSA(4.7) in CS-SA/DNA complexes significantly enhanced the dissociation of polymer/DNA complexes and improved the release of DNA intracellular without influencing their cellular uptake. The aforementioned results indicated that the acid group in protein played an important role in enhancing the transfection efficiency of CS/BSA/DNA complexes, and the study provided guidelines in the design of an efficient vector for DNA transfection. PMID:23679858

  4. Environmentally friendly surface modification of silk fiber: Chitosan grafting and dyeing

    NASA Astrophysics Data System (ADS)

    Davarpanah, Saideh; Mahmoodi, Niyaz Mohammad; Arami, Mokhtar; Bahrami, Hajir; Mazaheri, Firoozmehr

    2009-01-01

    In this paper, the surface modification of silk fiber using anhydrides to graft the polysaccharide chitosan and dyeing ability of the grafted silk were studied. Silk fiber was degummed and acylated with two anhydrides, succinic anhydride (SA) and phthalic anhydride (PA), in different solvents (dimethyl sulfoxide (DMSO) and N, N-dimethyl formamide (DMF)). The effects of anhydrides, solvents, anhydride concentration, liquor ratio (L:R) and reaction time on acylation of silk were studied. The polysaccharide chitosan was grafted to the acylated silk fiber and dyed by acid dye (Acid Black NB.B). The effects of pH, chitosan concentration, and reaction time on chitosan grafting of acylated silk were investigated. The physical properties show sensible changes regardless of weight gain. Scanning electron microscopy (SEM) analysis showed the presence of foreign materials firmly attached to the surface of silk. FTIR spectroscopy provided evidence that chitosan was grafted onto the acylated silk through the formation of new covalent bonds. The dyeing of the chitosan grafted-acylated silk fiber indicated the higher dye ability in comparison to the acylated and degummed silk samples. The mechanism of chitosan grafting over degummed silk through anhydride linkage was proposed. The findings of this research support the potential production of new environmentally friendly textile fibers. It is worthwhile to mention that the grafted samples have antibacterial potential due to the antibacterial property of chitosan molecules.

  5. Reusable nanocomposite of CoFe2O4/chitosan-graft-poly(acrylic acid) for removal of Ni(II) from aqueous solution

    NASA Astrophysics Data System (ADS)

    Nguyen, Van Cuong; Huynh, Thi Kim Ngoc

    2014-06-01

    In this paper, CoFe2O4/chitosan-graft-poly(acrylic acid) (CoFe2O4/CS-graft-PAA) nanocomposites were prepared successfully by coprecipitation of the compounds in alkaline solution and were used for removal of nickel (II) ions from aqueous solution. The sorption rate was affected significantly by the initial concentration of the solution, sorbent amount, and pH value of the solution. Batch experiments were conducted to investigate the adsorption capacity under different initial concentration (ranging from 25 to 150 mg L-1), solution pH (4.1, 5.3, 6.4 and 7.6), and contact time. These nanocomposites can be recycled conveniently from water with the assistance of an external magnet because of their exceptional properties. The prepared nanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), x-ray powder diffraction (XRD), and thermogravimetric analysis (TGA).

  6. Grafting of Chitosan and Chitosantrimethoxylsilylpropyl Methacrylate on Single Walled Carbon Nanotubes-Synthesis and Characterization

    PubMed Central

    Carson, Laura; Kelly-Brown, Cordella; Stewart, Melisa; Oki, Aderemi; Regisford, Gloria; Stone, Julia; Traisawatwong, Pasakorn; Durand-Rougely, Clarissa; Luo, Zhiping

    2011-01-01

    Acid functionalized single walled carbon nanotubes (CNTs) were grafted to chitosan by first reacting the oxidized CNTs with thionyl chloride to form acyl-chlorinated CNTs. This product was subsequently dispersed in chitosan and covalently grafted to form CNT-chitosan. CNT-chitosan was further grafted onto 3-trimethoxysilylpropyl methacrylate by free radical polymerization conditions, to yield CNT-g-chitosan-g-3-trimethoxysilylpropyl methacrylate (TMSPM), hereafter referred to as CNT-chitosan-3-TMSPM. These composites were characterized by Fourier Transform Infrared Resonance Spectroscopy (FTIR), carbon-13 nuclear magnetic resonance (13C NMR), Thermogravimetric Analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The composite showed improved thermal stability and could be of great potential use in bone tissue engineering. PMID:21765959

  7. Poly(itaconic acid)-grafted chitosan adsorbents with different cross-linking for Pb(II) and Cd(II) uptake.

    PubMed

    Kyzas, George Z; Siafaka, Panoraia I; Lambropoulou, Dimitra A; Lazaridis, Nikolaos K; Bikiaris, Dimitrios N

    2014-01-14

    Two novel chitosan (CS) adsorbents were prepared in powder form, after modification with the grafting of itaconic acid (CS-g-IA) and cross-linking with either glutaraldehyde (CS-g-IA(G)) or epichlorohydrin (CS-g-IA(E)). Their adsorption properties were evaluated in batch experiments for Cd(II) or Pb(II) uptake. Characterization techniques were applied to the prepared adsorbents as swelling experiments, TGA, SEM, XRD, and FTIR. Adsorption mechanisms were suggested for different pH conditions. Various adsorption parameters were determined as the effect of pH, contact time, and temperature. The maximum adsorption capacities for Cd(II) uptake were 405 and 331 mg/g for CS-g-IA(G) and CS-g-IA(E), respectively, revealing the capacity enhancement after grafting (124 and 92 mg/g were the respective values before grafting, respectively). A similar grafting effect was observed for Pb(II) uptake, proving its adsorption effectiveness on the CS backbone. The reuse of adsorbents was tested with 20 adsorption-desorption cycles. PMID:24011255

  8. Poly(methacrylic acid)-grafted chitosan microspheres via surface-initiated ATRP for enhanced removal of Cd(II) ions from aqueous solution.

    PubMed

    Huang, Liqiang; Yuan, Shaojun; Lv, Li; Tan, Guangqun; Liang, Bin; Pehkonen, S O

    2013-09-01

    Cross-linked chitosan (CCS) microspheres tethered with pH-sensitive poly(methacrylic acid) (PMAA) brushes were developed for the efficient removal of Cd(II) ions from aqueous solutions. Functional PMAA brushes containing dense and active carboxyl groups (COOH) were grafted onto the CCS microsphere surface via surface-initiated atom transfer radical polymerization (ATRP). Batch adsorption results showed that solution pH values had a major impact on cadmium adsorption by the PMAA-grafted CCS microspheres with the optimal removal observed above pH 5. The CCS-g-PMAA microsphere was found to achieve the adsorption equilibrium of Cd(II) within 1 h, much faster than about 7 h on the CCS microsphere. At pH 5 and with an initial concentration 0.089-2.49 mmol dm(-3), the maximum adsorption capacity of Cd(II), derived from the Langmuir fitting on the PMAA-grafted microspheres was around 1.3 mmol g(-1). Desorption and adsorption cycle experimental results revealed that the PMAA-grafted CCS microspheres loaded with Cd(II) can be effectively regenerated in a dilute HNO3 solution, and the adsorption capacity remained almost unchanged upon five cycle reuse. PMID:23755995

  9. Microspheres Assembled from Chitosan-Graft-Poly(lactic acid) Micelle-Like Core-Shell Nanospheres for Distinctly Controlled Release of Hydrophobic and Hydrophilic Biomolecules.

    PubMed

    Niu, Xufeng; Liu, Zhongning; Hu, Jiang; Rambhia, Kunal J; Fan, Yubo; Ma, Peter X

    2016-07-01

    To simultaneously control inflammation and facilitate dentin regeneration, a copolymeric micelle-in-microsphere platform is developed in this study, aiming to simultaneously release a hydrophobic drug to suppress inflammation and a hydrophilic biomolecule to enhance odontogenic differentiation of dental pulp stem cells in a distinctly controlled fashion. A series of chitosan-graft-poly(lactic acid) copolymers is synthesized with varying lactic acid and chitosan weight ratios, self-assembled into nanoscale micelle-like core-shell structures in an aqueous system, and subsequently crosslinked into microspheres through electrostatic interaction with sodium tripolyphosphate. A hydrophobic biomolecule either coumarin-6 or fluocinolone acetonide (FA) is encapsulated into the hydrophobic cores of the micelles, while a hydrophilic biomolecule either bovine serum albumin or bone morphogenetic protein 2 (BMP-2) is entrapped in the hydrophilic shells and the interspaces among the micelles. Both hydrophobic and hydrophilic biomolecules are delivered with distinct and tunable release patterns. Delivery of FA and BMP-2 simultaneously suppresses inflammation and enhances odontogenesis, resulting in significantly enhanced mineralized tissue regeneration. This result also demonstrates the potential for this novel delivery system to deliver multiple therapeutics and to achieve synergistic effects. PMID:26987445

  10. Synthesis and characterization of poly(maleic acid)-grafted crosslinked chitosan nanomaterial with high uptake and selectivity for Hg(II) sorption.

    PubMed

    Ge, Huacai; Hua, Tingting

    2016-11-20

    Chitosan-poly(maleic acid) nanomaterial (PMACS) with the size of 400-900nm was synthesized by grafting poly(maleic acid) onto chitosan and then crosslinking with glutaraldehyde. The synthesis conditions were optimized. The structure and morphology of PMACS were characterized by FT-IR, XRD, SEM and TGA. PMACS was used to adsorb some heavy metal ions such as Hg(II), Pb(II), Cu(II), Cd(II), Co(II), and Zn(II). The results indicated that PMACS had selectivity for Hg(II) sorption. The effects of various variables for sorption of Hg(II) were further explored. The maximum capacity for Hg(II) sorption was found to be 1044mgg(-1) at pH 6.0, which could compare with the maximal value of the recently reported other sorbents. The sorption followed the pseudo-second-order kinetics and Langmuir isotherm models. The rising of temperature benefited the uptake and the sorption was a spontaneous chemical process. The sorbent could be reused with EDTA. Hence, the nanomaterial would be used as a selective and high uptake sorbent in the removal of Hg(II) from effluents. PMID:27561493

  11. Preparation of porous carboxymethyl chitosan grafted poly (acrylic acid) superabsorbent by solvent precipitation and its application as a hemostatic wound dressing.

    PubMed

    Chen, Yu; Zhang, Yong; Wang, Fengju; Meng, Weiwei; Yang, Xinlin; Li, Peng; Jiang, Jianxin; Tan, Huimin; Zheng, Yongfa

    2016-06-01

    The volume phase transition of a hydrogel initiated by shrinking may result in complex patterns on its surface. Based on this unique property of hydrogel, we have developed a novel solvent precipitation method to prepare a kind of novel superabsorbent polymers with excellent hemostatic properties. A porous carboxymethyl chitosan grafted poly (acrylic acid) (CMCTS-g-PAA) superabsorbent polymer was prepared by precipitating CMCTS-g-PAA hydrogel with ethanol. Its potential application in hemostatic wound dressing was investigated. The results indicate that the modified superabsorbent polymer is non-cytotoxic. It showed a high swelling capacity and better hemostatic performance in the treatments of hemorrhage model of ear artery, arteria cruralis and spleen of the New Zealand white rabbit than the unmodified polymer and other commonly used clinic wound dressings. The hemostatic mechanism of the porous CMCTS-g-PAA polymer was also discussed. PMID:27040191

  12. Synthesis and characterization of carboxyl terminated poly(methacrylic acid) grafted chitosan/bentonite composite and its application for the recovery of uranium(VI) from aqueous media.

    PubMed

    Anirudhan, T S; Rijith, S

    2012-04-01

    A novel adsorbent poly(methacrylic acid)-grafted chitosan/bentonite (CTS-g-PMAA/Bent) composite was prepared through graft copolymerization reaction of methacrylic acid and chitosan in the presence of bentonite (Bent) and N,N'- methylenebisacrylamide as a crosslinker. The composite was well characterized using FTIR, XRD, XPS, SEM-EDS, surface area and zeta potential analyzers. The adsorption behavior of the composite toward uranium(VI) from aqueous media was studied under varying operating conditions of pH, concentration of U(VI), contact time, adsorbent dose and temperature. The optimum pH range for U(VI) adsorption was 5.5 at 30 °C. Concentration and temperature dependent rate constants were evaluated using pseudo-second-order kinetic model. The equilibrium data were correlated with the Langmuir isotherm model with an endothermic behavior. The equilibrium U(VI) sorption capacity was estimated to be 117.2 mg g(-1) at 30 °C. For the quantitative recovery of 100 mg L(-1) U(VI) from 1.0 L simulated nuclear industry wastewater, a minimum adsorbent dosage of 2.0 g CTS-g-PMAA/Bent was required. The calculated energy of activation (E(a) = 47.83 kJ/mol) was positively correlated with chemical adsorption process. The values of enthalpy, entropy and free energy of activation were calculated to explain the nature of adsorption process. Adsorption-desorption experiments over four cycles illustrate the feasibility of the repeated uses of this composite for the extraction of U(VI) from aqueous solutions. PMID:22304995

  13. Self-aggregated nanoparticles based on amphiphilic poly(lactic acid)-grafted-chitosan copolymer for ocular delivery of amphotericin B

    PubMed Central

    Zhou, Wenjun; Wang, Yuanyuan; Jian, Jiuying; Song, Shengfang

    2013-01-01

    Background The purpose of this study was to develop a self-aggregated nanoparticulate vehicle using an amphiphilic poly(lactic acid)-grafted-chitosan (PLA-g-CS) copolymer and to evaluate its potential for ocular delivery of amphotericin B. Methods A PLA-g-CS copolymer was synthesized via a “protection-graft-deprotection” procedure and its structure was confirmed by Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance, and X-ray diffraction spectra. Amphotericin B-loaded nanoparticles based on PLA-g-CS (AmB/PLA-g-CS) were prepared by the dialysis method and characterized for particle size, zeta potential, and encapsulation efficiency. Studies of these AmB/PLA-g-CS nanoparticles, including their mucoadhesive strength, drug release properties, antifungal activity, ocular irritation, ocular pharmacokinetics, and corneal penetration were performed in vitro and in vivo. Results Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance, and X-ray diffraction spectra showed that the PLA chains were successfully grafted onto chitosan molecules and that crystallization of chitosan was suppressed. The self-aggregated PLA-g-CS nanoparticles had a core-shell structure with an average particle size of approximately 200 nm and zeta potentials higher than 30 mV. Amphotericin B was incorporated into the hydrophobic core of the nanoparticles with high encapsulation efficiency. Sustained drug release from the nanoparticles was observed in vitro. The ocular irritation study showed no sign of irritation after instillation of the PLA-g-CS nanoparticles into rabbit eyes. The minimal inhibitory concentration of the AmB/PLA-g-CS nanoparticles showed antifungal activity similar to that of free amphotericin B against Candida albicans. The in vivo ocular pharmacokinetic study suggested that the PLA-g-CS nanoparticles have the advantage of prolonging residence time at the ocular surface. The corneal penetration study showed that the PLA-g-CS nanoparticles

  14. Real-time monitoring of peptide grafting onto chitosan films using capillary electrophoresis.

    PubMed

    Taylor, Danielle L; Thevarajah, Joel J; Narayan, Diksha K; Murphy, Patricia; Mangala, Melissa M; Lim, Seakcheng; Wuhrer, Richard; Lefay, Catherine; O'Connor, Michael D; Gaborieau, Marianne; Castignolles, Patrice

    2015-03-01

    Chitosan, being antimicrobial and biocompatible, is attractive as a cell growth substrate. To improve cell attachment, arginine-glycine-aspartic acid-serine (RGDS) peptides were covalently grafted to chitosan films, through the widely used coupling agents 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC-HCl) and N-hydroxysuccinimide (NHS), via the carboxylic acid function of the RGDS molecule. The grafting reaction was monitored, for the first time, in real time using free-solution capillary electrophoresis (CE). This enabled fast separation and determination of the peptide and all other reactants in one separation with no sample preparation. Covalent RGDS peptide grafting onto the chitosan film surface was demonstrated using solid-state NMR of swollen films. CE indicated that oligomers of RGDS, not simply RGDS, were grafted on the film, with a likely hyperbranched structure. To assess the functional properties of the grafted films, cell growth was compared on control and peptide-grafted chitosan films. Light microscopy and polymerase chain reaction (PCR) analysis demonstrated greatly improved cell attachment to RGDS-grafted chitosan films. PMID:25680633

  15. Molecular complex composed of β-cyclodextrin-grafted Chitosan and pH-sensitive amphipathic peptide for enhancing cellular cholesterol efflux under acidic pH.

    PubMed

    Takechi-Haraya, Yuki; Tanaka, Kento; Tsuji, Kohei; Asami, Yasuo; Izawa, Hironori; Shigenaga, Akira; Otaka, Akira; Saito, Hiroyuki; Kawakami, Kohsaku

    2015-03-18

    Excess of cholesterol in peripheral cells is known to lead to atherosclerosis. In this study, a molecular complex composed of β-cyclodextrin-grafted chitosan (BCC) and cellular cholesterol efflux enhancing peptide (CEEP), synthesized by modifying pH sensitive amphipathic GALA peptide, is introduced with the eventual aim of treating atherosclerosis. BCC has a markedly enhanced ability to induce cholesterol efflux from cell membranes compared to β-cyclodextrin, and the BCC-CEEP complex exhibited a 2-fold increase in cellular cholesterol efflux compared to BCC alone under weakly acidic conditions. Isothermal titration calorimetry and fluorescence spectroscopy measurements demonstrated that the random coil structure of CEEP at neutral pH converted to the α-helical structure at acidic pH, resulting in a three-order larger binding constant to BCC (K = 3.7 × 10(7) at pH 5.5) compared to that at pH 7.4 (K = 7.9 × 10(4)). Such high-affinity binding of CEEP to BCC at acidic pH leads to the formation of 100-nm-sized aggregate with positive surface charge, which would efficiently interact with cell membranes and induce cholesterol efflux. Since the cholesterol efflux ability of HDL is thought to be impaired under acidic environments in advanced atherosclerotic lesions, the BCC-CEEP complex might serve as a novel nanomaterial for treating atherosclerosis. PMID:25705984

  16. Cyclodextrin-grafted chitosan hydrogels for controlled drug delivery.

    PubMed

    Kono, Hiroyuki; Teshirogi, Taku

    2015-01-01

    A series of β-cyclodextrin-grafted carboxymethyl chitosan hydrogels (CD-g-CMCs) were prepared from carboxymethyl chitosan (CMC) and carboxymethyl β-chitosan (CMCD) using a water-soluble carbodiimide as a crosslinker in the presence of N-hydroxysuccinimide. Details of the hydrogel structures were determined via FTIR and solid-state NMR spectroscopic analyses. Increasing the feed ratio of CMCD to CMC in the reaction mixture led to an increase in CD grafting within the gel networks comprising CMC; this was confirmed by SEM observations and rheological analysis of the swollen hydrogels. The prepared CD-g-CMC hydrogels exhibited absorption properties toward acetylsalicylic acid (ASA, or Aspirin) due to the presence of CD in the structure; the amount of ASA absorbed into the hydrogels was enhanced with an increase in the amount of CD incorporated within the hydrogels. In addition, CD-g-CMC hydrogels provided a slower release of the entrapped ASA in comparison to the ASA release profile of a solely CMC-containing hydrogel. From these results, CD-g-CMC hydrogels have the potential to function as a biodegradable active material with controlled drug release ability. PMID:25192852

  17. Grafting of GMA and some comonomers onto chitosan for controlled release of diclofenac sodium.

    PubMed

    Sharma, Rajeev Kr; Lalita; Singh, Anirudh P; Chauhan, Ghanshyam S

    2014-03-01

    In order to develop pH sensitive hydrogels for controlled drug release we have graft copolymerized glycidyl methacrylate (GMA) with comonomers acrylic acid, acrylamide and acrylonitrile, onto chitosan (Ch) by using potassium persulphate (KPS) as free radical initiator in aqueous solution. The optimum percent grafting for GMA was recorded for 1g chitosan at [KPS]=25.00 × 10(-3)mol/L, [GMA]=0.756 × 10(-3)mol/L, reaction temperature=60 °C and reaction time=1h in 20 mL H2O. Binary monomers were grafted for five different concentrations at optimum grafting conditions evaluated for GMA alone onto chitosan. The graft copolymers were characterized by FTIR, XRD, TGA and SEM. The swelling properties of chitosan and graft copolymers were investigated at different pH to define their end uses in sustained release of an anti-inflammatory drug, diclofenac sodium. Percent drug release w.r.t. drug loaded in polymeric sample was studied as function of time in buffer solutions of pH 2.0 and 7.4. In vitro release data was analyzed using Fick's Law. Chitosan grafted with binary monomers, GMA-co-AAm and GMA-co-AN showed very good results for sustained release of drug at 7.4 pH. PMID:24374084

  18. Poly(ethylene glycol) grafted chitosan as new copolymer material for oral delivery of insulin

    NASA Astrophysics Data System (ADS)

    Ho, Thanh Ha; Thanh Le, Thi Nu; Nguyen, Tuan Anh; Chien Dang, Mau

    2015-09-01

    A new scheme of grafting poly (ethylene glycol) onto chitosan was proposed in this study to give new material for delivery of insulin over oral pathway. First, methoxy poly(ethylene glycol) amine (mPEGa MW 2000) were grafted onto chitosan (CS) through multiples steps to synthesize the grafting copolymer PEG-g-CS. After each synthesis step, chitosan and its derivatives were characterized by FTIR, 1H NMR Then, insulin loaded PEG-g-CS nanoparticles were prepared by cross-linking of CS with sodium tripolyphosphate (TPP). Same insulin loaded nanoparticles using unmodified chitosan were also prepared in order to compare with the modified ones. Results showed better protecting capacity of the synthesized copolymer over original CS. CS nanoparticles (10 nm of size) were gel like and high sensible to temperature as well as acidic environment while PEG-g-CS nanoparticles (200 nm of size) were rigid and more thermo and pH stable.

  19. pH responsive graft copolymers of chitosan.

    PubMed

    Yilmaz, Elvan; Yalinca, Zulal; Yahya, Kovan; Sirotina, Uliana

    2016-09-01

    Grafting suitable polymers onto chitosan can produce cationic or polyampholyte polymers or hydrogels that are potential smart biomedical materials. Chitosan-graft-[poly(diethylamino)ethyl methacrylate] has been prepared in three different physical forms as linear free chains in solution, chemical gels crosslinked with glutaraldehyde, and poly(diethylamino)ethyl methacrylate] grafted onto chitosan tripolyphosphate gel beads. In addition to chemical structure, the graft copolymers were characterized with respect to their dissolution and swelling behavior in aqueous solution. It has been established that solubility of the products is controlled by the grafting yield. While pH sensitive polymers, which collapse at a given pH value are obtained at lower grafting yields, hydrogels form at higher grafting yields with pH responsive swelling behavior. Glutaraldehyde crosslinked chitosan-graft-[poly(diethylamino)ethyl methacrylate] gels and chitosan tripolyphosphate gel beads grafted with poly[(diethylamino)ethyl methacrylate] exhibit pH sensitive swelling with highest equilibrium swelling capacity at pH=1.2. PMID:26500176

  20. Enzymatic grafting of peptides from casein hydrolysate to chitosan. Potential for value-added byproducts from food-processing wastes.

    PubMed

    Aberg, Christopher M; Chen, Tianhong; Olumide, Ayotunde; Raghavan, Srinivasa R; Payne, Gregory F

    2004-02-25

    Tyrosinase was used to initiate the grafting of peptides onto the amine-containing polysaccharide chitosan. Chemical evidence for covalent grafting was obtained from electrospray mass spectrometry for products formed from reactions with glucosamine (the monomeric unit of chitosan) and the model dipeptide Tyr-Ala. When this model dipeptide was incubated with tyrosinase and chitosan, there was a marked increase in the viscosity of the solution. This viscosity increase provides physical evidence that tyrosinase can initiate peptide grafting onto the chitosan backbone. A peptide-modified chitosan derivative was generated by reacting chitosan (0.32 w/v%) with acid-hydrolyzed casein (0.5 w/v %) using tyrosinase. After reaction, the peptide-modified chitosan was partially purified and dissolved in an aqueous acetic acid solution. Low concentrations of this peptide-modified chitosan were observed to confer viscoelastic properties to the solutions. Specifically they conferred high viscosities and shear thinning properties to the solutions, and solutions containing only 1 w/w % of the peptide-modified chitosan behaved as weak gels. Thus, tyrosinase provides a simple and safe way to convert food-processing byproducts into environmentally friendly products that offer useful functional properties. The selectivity of tyrosinase and the relatively high reactivity of chitosan's amines allow grafting to be performed with uncharacterized peptide mixtures present in crude hydrolysates. PMID:14969532

  1. Effect of kojic acid-grafted-chitosan oligosaccharides as a novel antibacterial agent on cell membrane of gram-positive and gram-negative bacteria.

    PubMed

    Liu, Xiaoli; Xia, Wenshui; Jiang, Qixing; Xu, Yanshun; Yu, Peipei

    2015-09-01

    Our work here, for the first time, reported the antibacterial activity of kojic acid-grafted-chitosan oligosaccharides (COS/KA) against three gram-positive and three gram-negative bacteria. Integrity of cell membrane, outer membrane (OM) and inner membrane (IM) permeabilization assay, alkaline phosphatase (ALP) and glucose-6-phosphate dehydrogenase (G6PDH) assay, and SDS-PAGE assay techniques were used to investigate the interactions between COS/KA and bacterial membranes. The antibacterial activity of COS/KA was higher than those of unmodified COS. The electric conductivity of bacteria suspensions increased, followed by increasing of the units of average release for ALP and G6PDH. COS/KA can also rapidly increase the 1-N-phenylanphthylamine (NPN) uptake and the release of β-galactosidase via increasing the permeability of OM and IM in Escherichia coli. SDS-PAGE indicated the content of cellular soluble proteins decreased significantly in COS/KA-treated bacteria. Hence, COS/KA has potential in food industry and biomedical sciences. PMID:25682520

  2. Preparation and characterization of chitosan-grafted-poly(2-amino-4,5-pentamethylene-thiophene-3-carboxylic acid N'-acryloyl-hydrazide) chelating resin for removal of Cu(II), Co(II) and Ni(II) metal ions from aqueous solutions.

    PubMed

    Bekheit, M M; Nawar, N; Addison, A W; Abdel-Latif, D A; Monier, M

    2011-05-01

    The graft copolymerization of ethylacrylate (EA) onto chitosan initiated by potassium persulphate and Mohr's salt combined redox initiator system in limited aqueous medium was carried out in heterogeneous media. Moreover, modification of the grafted chitosan was carried out by reaction of the ester group (-COOEt) with 2-amino-4,5-pentamethylene-thiophene-3-carboxylic acid hydrazide which eventually produce chitosan-grafted-poly(2-amino-4,5-pentamethylene-thiophene-3-carboxylic acid N'-acryloyl-hydrazide) (chitosan-g-ATAH) chelating resin. The application of the modified resin for metal ion uptake was studied using Cu(2+), Co(2+) and Ni(2+) ions. The modified chelating resins were characterized using FTIR spectroscopy, SEM and X-ray diffraction. PMID:21277322

  3. Immobilization and controlled release of β-galactosidase from chitosan-grafted hydrogels.

    PubMed

    Facin, Bruno R; Moret, Bruna; Baretta, Dilmar; Belfiore, Laurence A; Paulino, Alexandre T

    2015-07-15

    Chitosan-grafted hydrogels were employed for immobilization and controlled released of β-galactosidase. These hydrogels containing immobilized enzymes were employed to simulate the production of lactose-free food and controlled release of β-galactosidase into lactose-intolerant individuals. The degree of swelling, efficiency of immobilization (i.e., fractional uptake of enzyme), and controlled release were studied as a function of pH and temperature. The degrees of swelling decreased in acidic media: 49.4 g absorbed water per g hydrogel at pH 7.0, and 8.4 g absorbed water per g hydrogel at pH 3.5. The immobilization efficiency was 19%, indicating that chitosan-grafted hydrogels are promising matrices for enzyme adsorption and immobilization. Cyclic experiments reveal that chitosan-grafted hydrogels containing immobilized enzymes can be reused several times without introducing additional enzyme prior to each cycle. There is no significant decrease in the activity of the immobilized enzyme during reutilization studies. All results were conducted in triplicate by considering t-tests at a 95% significance level. Analysis of β-galactosidase activity and controlled release reveals that chitosan-grafted hydrogels containing immobilized enzymes are useful for the production of lactose-free food and controlled enzyme release with high performance. PMID:25722137

  4. Chitosan and chemically modified chitosan beads for acid dyes sorption.

    PubMed

    Azlan, Kamari; Wan Saime, Wan Ngah; Lai Ken, Liew

    2009-01-01

    The capabilities of chitosan and chitosan-EGDE (ethylene glycol diglycidyl ether) beads for removing Acid Red 37 (AR 37) and Acid Blue 25 (AB 25) from aqueous solution were examined. Chitosan beads were cross-linked with EGDE to enhance its chemical resistance and mechanical strength. Experiments were performed as a function of pH, agitation period and concentration of AR 37 and AB 25. It was shown that the adsorption capacities of chitosan for both acid dyes were comparatively higher than those of chitosan-EGDE. This is mainly because cross-linking using EGDE reduces the major adsorption sites -NH3+ on chitosan. Langmuir isotherm model showed the best conformity compared to Freundlich and BET. The kinetic experimental data agreed very well to the pseudo second-order kinetic model. The desorption study revealed that after three cycles of adsorption and desorption by NaOH and HCl, both adsorbents retained their promising adsorption abilities. FT-IR analysis proved that the adsorption of acid dyes onto chitosan-based adsorbents was a physical adsorption. Results also showed that chitosan and chitosan-EGDE beads were favourable adsorbers and could be employed as low-cost alternatives for the removal of acid dyes in wastewater treatment. PMID:19634439

  5. Thermo-responsive wound dressings by grafting chitosan and poly(N-isopropylacrylamide) to plasma-induced graft polymerization modified non-woven fabrics

    NASA Astrophysics Data System (ADS)

    Chen, Jyh-Ping; Kuo, Chang-Yi; Lee, Wen-Li

    2012-12-01

    To obtain a chitosan wound dressings with temperature-responsive characteristics, polypropylene (PP) non-woven fabric (NWF) was modified by direct current pulsed oxygen plasma-induced grafting polymerization of acrylic acid (AAc) to improve hydrophilicity and to introduce carboxylic acid groups. Conjugation of chitosan and poly(N-isopropylacrylamide) (PNIPAAm) followed by using water-soluble carbodiimide as a coupling agent to form a novel bigraft PP-g-chitosan-g-PNIPAAm wound dressing. The amount of chitosan and PNIPAAm grafted to PP-g-chitosan-g-PNIPAAm were 83.0 ± 4.6 μg/cm2 and 189.5 ± 8.2 μg/cm2, respectively. The surface chemical composition and microstructure of the NWF were studied by electron spectroscopy for chemical analysis (ESCA) and scanning electron microscopy (SEM). The linkages between AAc, chitosan, and PNIPAAm were confirmed with the formation of amide bonds. Physical properties of the NWF were characterized and potentials of these NWFs as wound dressings were evaluated using SD rat as the animal model. NWFs contained PNIPAAm were better than those contained only chitosan in wound healing rates and the wound areas covered by PP-g-chitosan-g-PNIPAAm wound dressings healed completely in 17 days.

  6. Enzymatic modification of chitosan by cinnamic acids: Antibacterial activity against Ralstonia solanacearum.

    PubMed

    Yang, Caifeng; Zhou, Yu; Zheng, Yu; Li, Changlong; Sheng, Sheng; Wang, Jun; Wu, Fuan

    2016-06-01

    This study aimed to identify chitosan polymers that have antibacterial activity against the bacterial wilt pathogen. The chitosan polymers were enzymatically synthesized using chitosan and five cinnamic acids (CADs): caffeic acid (CA), ferulic acid (FA), cinnamic acid (CIA), p-coumaric acid (COA) and chlorogenic acid (CHA), using laccase from Pleurotus ostreatus as a catalyst. The reaction was performed in a phosphate buffered solution under heterogenous reaction conditions. The chitosan derivatives (CTS-g-CADs) were characterized by FT-IR, XRD, TGA and SEM. FT-IR demonstrated that the reaction products bound covalently to the free amino groups or hydroxyl groups of chitosan via band of amide I or ester band. XRD showed a reduced packing density for grafted chitosan comparing to original chitosan. TGA demonstrated that CTS-g-CADs have a higher thermostability than chitosan. Additionally, chitosan and its derivatives showed similar antibacterial activity. However, the IC50 value of the chitosan-caffeic acid derivative (CTS-g-CA) against the mulberry bacterial wilt pathogen RS-5 was 0.23mg/mL, which was two-fifths of the IC50 value of chitosan. Therefore, the enzymatically synthesized chitosan polymers can be used to control plant diseases in biotechnological domains. PMID:26993531

  7. Radiation-induced graft polymerization of chitosan onto poly(3-hydroxybutyrate).

    PubMed

    Torres, Maykel González; Muñoz, Susana Vargas; Rosales, Silvia G Solís; Carreón-Castro, Ma del Pilar; Muñoz, Rodrigo Alonso Esparza; González, Roberto Olayo; González, Miriam Rocío Estévez; Talavera, Rogelio Rodríguez

    2015-11-20

    Chitosan is among the most studied biopolymers and offers important advantages, such as biodegradability, biocompatibility and nontoxicity. In this study, this polysaccharide was grafted onto poly(3-hydroxybutyrate) using the simultaneous gamma-irradiation-initiated polymerization method. The polyester was immersed in diverse solvents, which allowed the preparation of graft copolymers with different yields and crystallinities. A successful synthesis and the estimation of the degree of crystallinity were verified by spectroscopic and calorimetric techniques. The most suitable method was found to be the thermoanalytical approach because it displayed a linear relationship between the degree of crystallinity and the increasing degree of grafting. The results also indicated that the lowest degree of grafting was seen for acetic acid (14.27%), while the highest degree corresponded to ethyl acetate (32.11%). The mechanism of grafting was proposed on the basis of the experimental results. PMID:26344305

  8. Fabrication and characterization of heparin-grafted poly-L-lactic acid-chitosan core-shell nanofibers scaffold for vascular gasket.

    PubMed

    Wang, Ting; Ji, Xuyuan; Jin, Lin; Feng, Zhangqi; Wu, Jinghang; Zheng, Jie; Wang, Hongyin; Xu, Zhe-Wu; Guo, Lingling; He, Nongyue

    2013-05-01

    Electrospun nanofibers were widely studied to be applied as potential materials for tissue engineering. A new technology to make poly-l-lactic acid/chitosan core/shell nanofibers from heterologous solution by coaxial electrospinning technique was designed for vascular gasket. Chitosan surface was cross-linked by genipin and modified by heparin. Different ratios of PLA/CS in heterologous solution were studied to optimize the surface morphology of fibers. Clean core-shell structures formed with a PLA/CS ratio at 1:3. Superior biocompatibility and mechanical properties were obtained by optimizing the core-shell structure morphology and surface cross-linking of chitosan. UE7T-13 cells grew well on the core-shell structure fibers as indicated by methylthiazolyldiphenyl-tetrazolium bromide (MTT) results and scanning electron microscopy (SEM) images. Compared with the pure PLA fiber meshes and commercial vascular patch, PLA/CS core-shell fibers had better mechanical strength. The elastic modulus was as high as 117.18 MPa, even though the yield stress of the fibers was lower than that of the commercial vascular patch. Attachment of red blood cell on the fibers was evaluated by blood anticoagulation experiments and in vitro blood flow experiments. The activated partial thromboplastin time (APTT) and prothrombin time (PT) value from PLA/CS nanofibers were significantly longer than that of pure PLA fibers. SEM images indicated there were hardly any red blood cells attached to the fibers with chitosan coating and heparin modification. This type of fiber mesh could potentially be used as vascular gasket. PMID:23586670

  9. Controllable layer-by-layer assembly of PVA and phenylboronic acid-derivatized chitosan.

    PubMed

    Zhang, Dan; Yu, Guanghua; Long, Zhu; Yang, Guihua; Wang, Bin

    2016-04-20

    Phenylboronic acid-derivatized chitosan (chitosan-PBA) were prepared by grafting small molecules bearing phenylboronic acid groups onto chitosan with N-hydroxysuccinimide (NHS) and N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) as a coupling reagent pair. Self-assembly multilayer thin films of chitosan-PBA and poly(vinyl alcohol) were subsequently produced under pH control on supporting surfaces, either a silicon wafer or polystyrene latex particles. The driving force of the self-assembly was the ester formation of phenylboronic acid containing polymers with PVA, which can be "turned off" by simple pH control. PMID:26876848

  10. Grafting chitosan and polyHEMA on carbon nanotubes surfaces: "grafting to" and "grafting from" methods.

    PubMed

    Mahmoodian, Hossein; Moradi, Omid; Shariatzadeh, Behnam

    2014-02-01

    We report a simple method for engineering chitosan (CS) functionalized multi-walled carbon nanotube (MWCNT) composites with a biomedically important polymer, poly-2-hydroxyethyl methacrylate (polyHEMA), by chemical grafting HEMA monomers via free radical polymerization. Functionalization of CS and polyHEMA occurred in three steps. First, using microwave irradiation, CS was grafted onto the surface and sidewall of the carbon nanotubes. Second, HEMA monomers were grafted onto the polymeric matrix surface. The final step involved free radical polymerization of HEMA monomers. Composite synthesis was confirmed by Fourier transform infrared (FTIR) spectroscopy. Moreover, the presence of polyHEMA on the surface of the CS functionalized carbon nanotubes was confirmed by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and thermo gravimetric analysis (TGA) analyses. Furthermore, in the aqueous phase, our novel composites exhibited higher dispersibility compared with pristine MWCNTs. Considering the biomedical importance of polyHEMA and CS polymers, we expect these materials to be useful in the pharmaceutical industry as novel biomaterial composites with potential applications in drug delivery. PMID:24183808

  11. Preparation and characterization of catechin-grafted chitosan with antioxidant and antidiabetic potential.

    PubMed

    Zhu, Weili; Zhang, Zhanjun

    2014-09-01

    In the present study, the preparation, characterization, antioxidant and antidiabetic activities of catechin-grafted chitosan (catechin-g-chitosan) were investigated. The graft of catechin onto chitosan was achieved by redox system and confirmed using various instrumental methods. Proton nuclear magnetic resonance spectroscopy indicates that catechin has been successfully grafted onto chitosan. The morphology observation shows that chitosan changes to a softened nature with porous surface after grafting. Catechin-g-chitosan also exhibits reduced thermal stability and enhanced crystallinity compared to chitosan. Moreover, catechin-g-chitosan shows 0.51 of reducing power, 46.81% of hydroxyl radical-scavenging activity and 67.08% of DPPH radical-scavenging activity at 1mg/ml, which are much higher than that of chitosan. The antidiabetic activity in vitro assays shows that the α-glucosidase inhibitory effect decreases in the order of catechin-g-chitosan>catechin>acarbose>chitosan, and the α-amylase inhibitory effect decreases in the order of acarbose>catechin-g-chitosan>catechin>chitosan. The improved antioxidant and antidiabetic activities of catechin-g-chitosan are attributed to the phenolic groups in the catechin residues. PMID:24995632

  12. Complexes of Silver(I) Ions and Silver Phosphate Nanoparticles with Hyaluronic Acid and/or Chitosan as Promising Antimicrobial Agents for Vascular Grafts

    PubMed Central

    Chudobova, Dagmar; Nejdl, Lukas; Gumulec, Jaromir; Krystofova, Olga; Rodrigo, Miguel Angel Merlos; Kynicky, Jindrich; Ruttkay-Nedecky, Branislav; Kopel, Pavel; Babula, Petr; Adam, Vojtech; Kizek, Rene

    2013-01-01

    Polymers are currently widely used to replace a variety of natural materials with respect to their favourable physical and chemical properties, and due to their economic advantage. One of the most important branches of application of polymers is the production of different products for medical use. In this case, it is necessary to face a significant disadvantage of polymer products due to possible and very common colonization of the surface by various microorganisms that can pose a potential danger to the patient. One of the possible solutions is to prepare polymer with antibacterial/antimicrobial properties that is resistant to bacterial colonization. The aim of this study was to contribute to the development of antimicrobial polymeric material ideal for covering vascular implants with subsequent use in transplant surgery. Therefore, the complexes of polymeric substances (hyaluronic acid and chitosan) with silver nitrate or silver phosphate nanoparticles were created, and their effects on gram-positive bacterial culture of Staphylococcus aureus were monitored. Stages of formation of complexes of silver nitrate and silver phosphate nanoparticles with polymeric compounds were characterized using electrochemical and spectrophotometric methods. Furthermore, the antimicrobial activity of complexes was determined using the methods of determination of growth curves and zones of inhibition. The results of this study revealed that the complex of chitosan, with silver phosphate nanoparticles, was the most suitable in order to have an antibacterial effect on bacterial culture of Staphylococcus aureus. Formation of this complex was under way at low concentrations of chitosan. The results of electrochemical determination corresponded with the results of spectrophotometric methods and verified good interaction and formation of the complex. The complex has an outstanding antibacterial effect and this effect was of several orders higher compared to other investigated complexes

  13. Preparation and properties of polyester fabrics grafted with O-carboxymethyl chitosan.

    PubMed

    Lv, Jingchun; Zhou, Qingqing; Liu, Guoliang; Gao, Dawei; Wang, Chunxia

    2014-11-26

    Carboxymethyl chitosan (CMCS) was prepared with a view to develop a multifunctional finish on saponified polyethylene terephthalate (PET) fabric. CMCS was synthesized by chemical reaction with chloroacetic acid, and its chemical structure was characterized by Fourier Transform Infrared Spectrum (FTIR) and nuclear magnetic resonance (NMR). CMCS was grafted on saponified PET fabric using 3-(3-dimethylaminopropyl)-1-ethylcarbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS) and polyethylenimine (PEI)/glutaraldehyde (GA) as cross-linking agent. FTIR, scanning electron microscope (SEM) and energy dispersive X-ray (EDX) analyses confirmed CMCS grafting on saponified PET fabric surface. TGA indicated saponification and CMCS grafting did not affect thermal property of PET fabric. The CMCS grafting greatly improved wettability, antistatic property of saponified PET fabric without harmful effect on their physico-mechanical properties. PMID:25256493

  14. The coagulation characteristics of humic acid by using acid-soluble chitosan, water-soluble chitosan, and chitosan coagulant mixtures.

    PubMed

    Chen, Chih-Yu; Wu, Chung-Yu; Chung, Ying-Chien

    2015-01-01

    Chitosan is a potential substitute for traditional aluminium salts in water treatment systems. This study compared the characteristics of humic acid (HA) removal by using acid-soluble chitosan, water-soluble chitosan, and coagulant mixtures of chitosan with aluminium sulphate (alum) or polyaluminium chloride (PACl). In addition, we evaluated their respective coagulation efficiencies at various coagulant concentrations, pH values, turbidities, and hardness levels. Furthermore, we determined the size and settling velocity of flocs formed by these coagulants to identify the major factors affecting HA coagulation. The coagulation efficiency of acid- and water-soluble chitosan for 15 mg/l of HA was 74.4% and 87.5%, respectively. The optimal coagulation range of water-soluble chitosan (9-20 mg/l) was broader than that of acid-soluble chitosan (4-8 mg/l). Notably, acid-soluble chitosan/PACl and water-soluble chitosan/alum coagulant mixtures exhibited a higher coagulation efficiency for HA than for PACl or alum alone. Furthermore, these coagulant mixtures yielded an acceptable floc settling velocity and savings in both installation and operational expenses. Based on these results, we confidently assert that coagulant mixtures with a 1:1 mass ratio of acid-soluble chitosan/PACl and water-soluble chitosan/alum provide a substantially more cost-effective alternative to using chitosan alone for removing HA from water. PMID:25362971

  15. Grafting of chitosan as a biopolymer onto wool fabric using anhydride bridge and its antibacterial property.

    PubMed

    Ranjbar-Mohammadi, Marziyeh; Arami, Mokhtar; Bahrami, Hajir; Mazaheri, Firoozmehr; Mahmoodi, Niyaz Mohammad

    2010-04-01

    Weak binding of chitosan on the wool constitutes the main problem in its application. In this paper, the surface modification of wool fabric using anhydrides to graft the chitosan was studied. Weight gain, antibacterial and antifelting properties of the chitosan grafted-acylated wool fabric were investigated. Wool fabrics were acylated with two anhydrides, succinic anhydride (SA) and phthalic anhydride (PA), using different solvents (dimethylsulfoxide (DMSO) and N,N-dimethyl formamide (DMF)). The effects of anhydrides, solvents, anhydride concentration, liquor ratio (L:R) and reaction time on acylation of wool were investigated. Chitosan was grafted to the acylated wool and the effects of pH, chitosan concentration, and reaction time on chitosan grafting of acylated wool were evaluated. Fourier transform infra-red (FTIR), scanning electron microscope (SEM), differential scanning colorimetry (DSC) and weight gain analyses provided evidence that chitosan was grafted on to the acylated wool through the formation of new covalent bonds. The grafted samples have antibacterial potential due to existence of the antibacterial property of chitosan. In addition, the chitosan grafted-acylated wool samples have antifelting property. The findings of this research support the potential production of new environmentally friendly textile fabrics. PMID:20022732

  16. Noncovalently functionalized multiwalled carbon nanotubes by chitosan-grafted reduced graphene oxide and their synergistic reinforcing effects in chitosan films.

    PubMed

    Pan, Yongzheng; Bao, Hongqian; Li, Lin

    2011-12-01

    Water-soluble chitosan-grafted reduced graphene oxide (CS-rGO) sheets are successfully synthesized via amidation reaction and chemical reduction. CS-rGO possesses not only remarkable graphitic property but also favorable water solubility, which is found to be able to effectively disperse multiwalled carbon nanotubes (MWCNTs) in acidic solutions via noncovalent interaction. The efficiency of CS-rGO in dispersing MWCNTs is tested to be higher than that of plain graphene oxide (GO) and a commercial surfactant, sodium dodecyl sulfate (SDS). With incorporation of 1 wt % CS-rGO dispersed MWCNTs (CS-rGO-MWCNTs), the tensile modulus, strength and toughness of the chitosan (CS) nanocomposites can be increased by 49, 114, and 193%, respectively. The reinforcing and toughening effects of CS-rGO-MWCNTs are much more prominent than those of single-component fillers, such as MWCNTs, GO, and CS-rGO. Noncovalent π-π interactions between graphene sheets and nanotubes and hydrogen bonds between grafted CS and the CS matrix are responsible for generating effective load transfer between CS-rGO-MWCNTs and the CS matrix, causing the simultaneously increased strength and toughness of the nanocomposites. PMID:22091530

  17. Preparation of lignosulfonate-acrylamide-chitosan ternary graft copolymer and its flocculation performance.

    PubMed

    He, Kunpeng; Lou, Tao; Wang, Xuejun; Zhao, Wenhua

    2015-11-01

    As flocculant plays an important role in wastewater treatment, searching for high efficient and cost-effective flocculants has always become the challenge in chemical industry. In the current work, lignosulfonate-acrylamide-chitosan ternary copolymer was designed and prepared as a new kind of flocculant. The elemental analysis and structure characterization of FTIR and XRD showed that acrylamide successfully grafted onto the two natural polymers and amorphous macromolecules were formed. The natural polymers-based flocculant was water soluble and pH independent. As it had multiple functional groups from the raw materials, the amphoteric flocculant showed high color removal efficiency to anionic (acid blue 113, >95%), neutral (reactive black 5, >95%) and cationic dyes (methyl orange, >50%) in a wide range of flocculant dosage and pH windows. The ternary flocculant, based on lignosulfonate, chitosan, and acrylamide, might be a promising material in practical applications from the perspective of cost, source and performance. PMID:26432366

  18. Synthesis and characterization of noncytotoxic and biodegradable polymethacrylates-grafted chitosan gels.

    PubMed

    Adalı, Terin

    2013-01-01

    Poly(methacrylates), namely 2-hydroxy ethyl methacrylate (HEMA), ethylene glycol dimethacrylate (EGDMA) and triethylene glycol dimethacrylate (TEGDMA) were grafted onto chitosan by using ceric ammonium nitrate as a redox initiator. Semi-IPN gels of chitosan-graft-poly(HEMA)-graft-poly(EGDMA) and chitosan-graft-poly(HEMA)-graft-poly(TEGDMA) were obtained. The grafting conditions were optimized with respect to monomer concentrations. The products were characterized by TGA, FTIR, XRD and SEM techniques. The solubility of the grafted products in aqueous medium decreased with increasing grafting percentage. The insoluble gels exhibited a highly pH sensitive swelling behaviour. TGA thermograms showed that poly(HEMA)/poly(TEGDMA)-grafted product is much more stable than poly(HEMA)/poly(EGDMA)-grafted product showing that TEGDMA is a more effective crosslinker than EGDMA. According to XRD analysis TEGDMA has a higher tendency to form ordered structures than EGDMA as it is capable of chain folding. The results of cytotoxicity studies revealed that the methacrylate-grafted chitosans were noncytotoxic and good candidates for biomedical applications. PMID:23988707

  19. Synthesis of Novel Pyrimethanil Grafted Chitosan Derivatives with Enhanced Antifungal Activity.

    PubMed

    Li, Yan; Liu, Song; Qin, Yukun; Xing, Ronge; Chen, Xiaolin; Li, Kecheng; Li, Pengcheng

    2016-01-01

    In this study, three pyrimethanil grafted chitosan (PML-g-CS) derivatives were obtained. The structures of the conjugates were confirmed by FT-IR, (1)H NMR, and EA. The grafting ratios were measured by HPLC. Antifungal properties of pyrimethanil grafted chitosan (PML-g-CS) derivatives against the plant pathogenic fungi Rhizoctonia solani and Gibberella zeae were investigated at concentrations of 100, 200, and 400 mg/L. The PML-g-CS derivatives showed enhanced antifungal activity in comparison with chitosan. The PML-g-CS-1 showed the best antifungal activity against R. solani, whose antifungal index was 58.32%. The PML-g-CS-2 showed the best antifungal activity against G. zeae, whose antifungal index was 53.48%. The conjugation of chitosan and pyrimethanil showed synergistic effect. The PML-g-CS derivatives we developed showed potential for further study and application in crop protection. PMID:27529072

  20. Synthesis of Novel Pyrimethanil Grafted Chitosan Derivatives with Enhanced Antifungal Activity

    PubMed Central

    Liu, Song; Xing, Ronge; Chen, Xiaolin

    2016-01-01

    In this study, three pyrimethanil grafted chitosan (PML-g-CS) derivatives were obtained. The structures of the conjugates were confirmed by FT-IR, 1H NMR, and EA. The grafting ratios were measured by HPLC. Antifungal properties of pyrimethanil grafted chitosan (PML-g-CS) derivatives against the plant pathogenic fungi Rhizoctonia solani and Gibberella zeae were investigated at concentrations of 100, 200, and 400 mg/L. The PML-g-CS derivatives showed enhanced antifungal activity in comparison with chitosan. The PML-g-CS-1 showed the best antifungal activity against R. solani, whose antifungal index was 58.32%. The PML-g-CS-2 showed the best antifungal activity against G. zeae, whose antifungal index was 53.48%. The conjugation of chitosan and pyrimethanil showed synergistic effect. The PML-g-CS derivatives we developed showed potential for further study and application in crop protection. PMID:27529072

  1. Pyridine-grafted chitosan derivative as an antifungal agent.

    PubMed

    Jia, Ruixiu; Duan, Yunfei; Fang, Qiang; Wang, Xiangyang; Huang, Jianying

    2016-04-01

    Pyridine moieties were introduced into chitosan by nucleophilic substitution to afford N-(1-carboxybutyl-4-pyridinium) chitosan chloride (pyridine chitosan). The resulting chitosan derivative was well characterized, and its antifungal activity was examined, based on the inhibition of mycelial growth and spore germination. The results indicated that pyridine chitosan exhibited enhanced antifungal activity by comparison with pristine chitosan. The values of the minimum inhibitory concentration and the minimal fungicidal concentration of pyridine chitosan against Fulvia fulva were 0.13 mg/ml and 1 mg/ml, respectively, while the corresponding values against Botrytis cinerea were 0.13 mg/ml and 4 mg/ml, respectively. Severe morphological changes of pyridine chitosan-treated B. cinerea were observed, indicative that pyridine chitosan could damage and deform the structure of fungal hyphae and subsequently inhibit strain growth. Non-toxicity of pyridine chitosan was demonstrated by an acute toxicity study. These results are beneficial for assessing the potential utilization of this chitosan derivative and for exploring new functional antifungal agents with chitosan in the food industry. PMID:26593505

  2. Synthesis and characterization of a brush-like copolymer of polylactide grafted onto chitosan.

    PubMed

    Liu, Y; Tian, F; Hu, K A

    2004-03-15

    A brush-like poly(DL)-lactide grafted onto chitosan as the backbone was investigated. The graft copolymerization was carried out with triethylaluminum as catalyst in toluene at 70 degrees C. It was found that a greater lactide content in the feeding ratio results in a higher grafting percentage. FTIR spectrometry, (1)H NMR, DSC scanning, and wide-angle X-ray scattering, respectively, are used to characterize these branch copolymers. A copolymer has a definite melting point when the molar feeding ratio of lactide to chitosan is more than 10:1, and the deltaH of the copolymers increases with the feed ratio of lactide to chitosan in feeding. PMID:14980828

  3. Detection of trace amounts of Pb(II) by schiff base-chitosan-grafted multiwalled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Moghimi, Ali

    2013-07-01

    A simple, highly sensitive, accurate and selective method for determination of trace amounts of Pb(II) in water samples is presented. A novel Schiff base-chitosan-grafted multiwalled carbon nanotubes (S-CS-MWCNTs) solid-phase extraction adsorbent was synthesized by covalently grafting a Schiff base-chitosan (S-CS) onto the surfaces of oxidized MWCNTs. The stability of a chemically (S-CS-MWCNTs) especially in concentrated hydrochloric acid which was then used as a recycling and preconcentration reagent for further uses of (S-CS-MWCNTs). The method is based on selective chelation of Pb(II) on surfactant coated C18, modified with a Schiff base-chitosan-grafted multiwalled carbon nanotubes (S-CS-MWCNTs). The retained ions were then eluted with 4 mL of 4 M nitric acid and determined by flame atomic absorption spectrometry (FAAS) at 283.3 nm for Pb. The influence of flow rates of sample and eluent solutions, pH, break-through volume, effect of foreign ions on chelation and recovery were investigated. 1.5 g of surfactant coated C18 adsorbs 40 mg of the Schiff s base which in turn can retain 15.0 ± 0.9 mg of each of the two ions. The limit of detection (3σ) for Pb(II) was found to be 3.20 ng L-1. The enrichment factor for both ions are 100. The mentioned method was successfully applied on determination of lead in different water samples. The ions were also speciated by means of three columns system.

  4. Chitosan-graft-poly(n-butyl acrylate) copolymer: Synthesis and characterization of a natural/synthetic hybrid material.

    PubMed

    Anbinder, Pablo; Macchi, Carlos; Amalvy, Javier; Somoza, Alberto

    2016-07-10

    Two chitosan polymers with different deacetylation degree and molecular weight were subjected to grafting reactions with the aim to enhance the properties of these bio-based materials. Specifically, n-butyl acrylate in different proportions was grafted onto two different deacetylation degree (DD%) chitosan using radical initiation in a surfactant free emulsion system. Infrared spectroscopy was used to confirm grafting and products grafting percentage and efficiency were evaluated against acrylate/chitosan ratio and DD%. Thermal and structural properties and the behavior against water of the raw and grafted biopolymers were studied using several experimental techniques: differential scanning calorimetry, transmission electron microscopy, dynamic light scattering, water swelling, contact angle and positron annihilation lifetime spectroscopy. The influence of the grafting process on the morphological and physicochemical properties of the prepared natural/synthetic hybrid materials is discussed. PMID:27106155

  5. BisGMA-polyvinylpyrrolidone blend based nanocomposites reinforced with chitosan grafted f-multiwalled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Praharaj, A.; Behera, D.; Rath, P.; Bastia, T. K.; Rout, A. K.

    In this work, initially a non-destroyable surface grafting of acid functionalized multiwalled carbon nanotubes (f-MWCNTs) with biopolymer chitosan (CS) was carried out using glutaraldehyde as a cross-linking agent via the controlled covalent deposition method which was characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Then, BisGMA (bisphenol-A glycidyldimethacrylate)-polyvinylpyrrolidone (PVP) blend was prepared (50:50 wt%) by a simple sonication method. The CS grafted f-MWCNTs (CS/f-MWCNTs) were finally dispersed in BisGMA-PVP blend (BGP50) system in different compositions i.e. 0, 2, 5 and 7 wt% and pressed into molds for the fabrication of reinforced nanocomposites which were characterized by SEM. Nanocomposites reinforced with 2 wt% raw MWCNTs and acid f-MWCNTs were also fabricated and their properties were studied in detail. The results of comparative study report lower values of the investigated properties in nanocomposites with 2 wt% raw and f-MWCNTs than the one with 2 wt% CS/f-MWCNTs proving it to be a better reinforcing nanofiller. Further, the mechanical behavior of the nanocomposites with various CS/f-MWCNTs content showed a dramatic increase in Young's Modulus, tensile strength, impact strength and hardness along with improved dynamic mechanical, thermal and electrical properties at 5 wt% content of CS/f-MWCNTs. The addition of CS/f-MWCNTs also resulted in reduced corrosion and swelling properties. Thus, the fabricated nanocomposites with optimum nanofiller content could serve as low cost and light weight structural, thermal and electrical materials compatible in various corrosive and solvent based environments.

  6. Red fluorescent chitosan nanoparticles grafted with poly(2-methacryloyloxyethyl phosphorylcholine) for live cell imaging.

    PubMed

    Wang, Ke; Fan, Xingliang; Zhang, Xiaoyong; Zhang, Xiqi; Chen, Yi; Wei, Yen

    2016-08-01

    Poly(2-methacryloyloxyethyl phosphorylcholine) conjugated red fluorescent chitosan nanoparticles (GCC-pMPC) were facilely fabricated by "grafting from" method via surface initiated atom transfer radical polymerization (ATRP). Firstly, glutaraldehyde crosslinked red fluorescent chitosan nanoparticles (GCC NPs) with many amino groups and hydroxyl groups on their surface were prepared, which were then reacted with 2-bromoisobutyryl bromide to form GCC-Br; subsequently, poly(MPC) (pMPC) brushes were grafted onto GCC NPs surface using GCC-Br as initiator via ATRP. Compared with PEGylated nanoparticles, zwitterionic polymers modified nanoparticles demonstrated better performance in their cellular uptake. Moreover, the obtained GCC-pMPC demonstrated excellent water-dispersibility, biocompatibility, and photostability, which made them highly potential for long-term tracing applications. Importantly, the successful live cell imaging of GCC-pMPC would remarkably advance the research of their further bioapplications. PMID:27088188

  7. Free radical grafting kinetics of acrylamide onto a blend of starch/chitosan/alginate.

    PubMed

    Sorour, Mohamed; El-Sayed, Marwa; El Moneem, Nabil Abd; Talaat, Hala; Shaalan, Hayam; El Marsafy, Sahar

    2013-10-15

    Grafting of monomer onto polymer backbone is one of the effective and accessible methods for the chemical modification of polysaccharides. Grafting of acrylamide (AAm) onto polysaccharides blend (PsB) composed of starch, chitosan and alginate has been carried out using potassium persulfate (KPS) as an initiator. The kinetics of the grafting polymerization also has been studied. The grafting parameters have been evaluated by changing the initial concentrations of AAm from 8 to 16 g, PsB from 6 to 14 g and KPS from 0.2 to 1 g. Evidence of grafting has been obtained from FTIR, XRD and TGA. The kinetics of the grafting polymerization also has been studied. The grafting rate equation of the produced hydrogel (PsB-g-AAm) hydrogel has been expressed by: Rg=k[AAm] [PsB](0.5) [KPS](0.5). The grafting rate is a first order dependence to [AAm] initial concentration and square root to [PsB] and [KPS] initial concentrations in the used concentrations range. PMID:23987368

  8. Glial cell line-derived neurotrophic factor gene delivery via a polyethylene imine grafted chitosan carrier

    PubMed Central

    Peng, Yu-Shiang; Lai, Po-Liang; Peng, Sydney; Wu, His-Chin; Yu, Siang; Tseng, Tsan-Yun; Wang, Li-Fang; Chu, I-Ming

    2014-01-01

    Parkinson’s disease is known to result from the loss of dopaminergic neurons. Direct intracerebral injections of high doses of recombinant glial cell line-derived neurotrophic factor (GDNF) have been shown to protect adult nigral dopaminergic neurons. Because GDNF does not cross the blood–brain barrier, intracerebral gene transfer is an ideal option. Chitosan (CHI) is a naturally derived material that has been used for gene transfer. However, the low water solubility often leads to decreased transfection efficiency. Grafting of highly water-soluble polyethylene imines (PEI) and polyethylene glycol onto polymers can increase their solubility. The purpose of this study was to design a non-viral gene carrier with improved water solubility as well as enhanced transfection efficiency for treating Parkinsonism. Two molecular weights (Mw =600 and 1,800 g/mol) of PEI were grafted onto CHI (PEI600-g-CHI and PEI1800-g-CHI, respectively) by opening the epoxide ring of ethylene glycol diglycidyl ether (EX-810). This modification resulted in a non-viral gene carrier with less cytotoxicity. The transfection efficiency of PEI600-g-CHI/deoxyribonucleic acid (DNA) polyplexes was significantly higher than either PEI1800-g-CHI/DNA or CHI/DNA polyplexes. The maximal GDNF expression of PEI600-g-CHI/DNA was at the polymer:DNA weight ratio of 10:1, which was 1.7-fold higher than the maximal GDNF expression of PEI1800-g-CHI/DNA. The low toxicity and high transfection efficiency of PEI600-g-CHI make it ideal for application to GDNF gene therapy, which has potential for the treatment of Parkinson’s disease. PMID:25061293

  9. Ethyl chitosan synthesis and quantification of the effects acquired after grafting it on a cotton fabric, using ANOVA statistical analysis.

    PubMed

    Popescu, Vasilica; Muresan, Augustin; Popescu, Gabriel; Balan, Mihaela; Dobromir, Marius

    2016-03-15

    Three ethyl chitosans (ECSs) have been prepared using the ethyl chloride (AA) that was obtained in situ. Each ECS was applied on a 100% cotton fabric through a pad-dry-cure technology. Using the ANOVA as statistic method, the wrinkle-proofing effects have been determined varying the concentrations of AA (0.1-2.1mmol) and chitosan (CS) (0.1-2.1mmol). Alkylation and grafting mechanisms have been confirmed by the results of FTIR, (1)H NMR, XPS, SEM, DSC and termogravimetric analyses. The performances of each ECS as wrinkle-proofing agent have been revealed through quantitative methods (taking-up degree, wrinkle-recovering angle, tensile strength and effect's durability). The ECSs confer wrinkle-recovering angle and tensile strength higher than those of the witness sample. Durability of ECSs grafted on cotton have been demonstrated by a good capacity of dyeing with non-specific (acid/anionic and cationic) dyes under severe working conditions (100°C, 60min) and a good antimicrobial capacity. PMID:26794742

  10. Synthesis, characterization, and biocompatible properties of alanine-grafted chitosan copolymers.

    PubMed

    Park, Gyu Han; Kang, Min-Sil; Knowles, Jonathan C; Gong, Myoung-Seon

    2016-04-01

    In order to overcome major problems regarding the lack of affinity to solvents and limited reactivity of the free amines of chitosan, introduction of appropriate spacer arms having terminal amine function is considered of interest.L-Alanine-N-carboxyanhydride was grafted onto chitosan via anionic ring-opening polymerization. The chemical and structural characterizations ofL-alanine-grafted chitosan (Ala-g-Cts) were confirmed through Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy ((1)H NMR). In addition, the viscoelastic properties ofAla-g-Cts were examined by means of a rotational viscometer, and thermal analysis was carried out with a thermogravimetric analyzer and differential scanning calorimetry. Morphological changes in the chitosanL-alanine moiety were determined by x-ray diffraction. To determine the feasibility of using these films as biomedical materials, we investigated the effects of theirL-alanine content on physical and mechanical properties. The biodegradation results of crosslinkedAla-g-Cts films were evaluated in phosphate-buffered solution containing lysozyme at 37℃. Proliferation of MC3T3-E1 cells on crosslinkedAla-g-Cts films was also investigated with use of the CCK-8 assay. PMID:26767393

  11. Synthesis and characterization of new biocompatible copolymer: chitosan-graft-polyaniline

    NASA Astrophysics Data System (ADS)

    Sedaghat, Sajjad

    2014-03-01

    Polyaniline as a conductive polymer and chitosan as a natural polymer have been reacted with formaldehyde as grafting agent and potassium persulfate as an initiator. The effect of using specific primer, different ratio of monomers and the solubility of synthesized copolymer has been studied and analyzed. Characterization of this new copolymer were occurred by Fourier transform infrared spectroscopy, UV-visible, scanning electron microscopy and differential scanning calorimetry technique.

  12. Synthesis and characterization of new biocompatible copolymer: chitosan-graft-polyaniline

    NASA Astrophysics Data System (ADS)

    Sedaghat, Sajjad

    2014-01-01

    Polyaniline (PAni) as a conductive polymer and chitosan (CS) as a natural polymer have been reacted with formaldehyde as a grafting agent and potassium persulfate as an initiator. The effect of using specific primer, different ratios of monomers, and the solubility of synthesized copolymer has been studied and analyzed here. This new copolymer was characterized by Fourier transform infrared spectroscopy (FT-IR), UV-visible, scanning electron microscopy (SEM), and differential scanning calorimetry (DSC) techniques.

  13. Reactive blending of thermoplastic starch and polyethylene-graft-maleic anhydride with chitosan as compatibilizer.

    PubMed

    Jantanasakulwong, Kittisak; Leksawasdi, Noppol; Seesuriyachan, Phisit; Wongsuriyasak, Somchai; Techapun, Charin; Ougizawa, Toshiaki

    2016-11-20

    Cassava starch was melt-blended with glycerol (70/30wt%/wt%) at 140°C to prepare thermoplastic starch (TPS). Chitosan (CTS) was premixed with starch and glycerol, in acidified water (lactic acid 2wt%), at 1, 5 and 10wt%/wt%. TPS/CTS was then melt-blended (160°C) with polyethylene-graft-maleic anhydride (PE-MAH). Phase determination and scanning electron microscopy indicated TPS/PE-MAH/CTS had a co-continuous morphology and CTS-induced phase inversion to give dispersed PE-MAH particles in a TPS matrix. Tensile strength at break and elongation, melt viscosity, fracture toughness and water contact angle of TPS/PE-MAH were improved by CTS incorporation. TPS/PE-MAH/CTS blends decreased the melting temperature of TPS and PE-MAH compared to the neat polymers. FTIR confirmed a reaction had occurred between amino groups (NH2) of CTS and the MAH groups of PE-MAH. This reaction and the enhanced miscibility between TPS and CTS improved the mechanical properties of the TPS/PE-MAH/CTS blend, particularly at 5wt%/wt% CTS. PMID:27561475

  14. Galactosyl conjugated N-succinyl-chitosan-graft-polyethylenimine for targeting gene transfer.

    PubMed

    Lu, Bo; Wu, De-Qun; Zheng, Hua; Quan, Chang-Yun; Zhang, Xian-Zheng; Zhuo, Ren-Xi

    2010-12-01

    Through incorporating lactobionic acid (LA) bearing a galactose group to N-succinyl-chitosan-graft-polyethylenimine (NSC-g-PEI), NSC-g-PEI-LA copolymers were synthesized as gene vectors with hepatocyte targeting properties. The molecular weight and composition of NSC-g-PEI-LA copolymers were characterized using gel permeation chromatography (GPC) and (1)H nuclear magnetic resonance spectroscopy ((1)H NMR) respectively. Agarose gel electrophoresis assays showed good DNA binding ability of NSC-g-PEI-LA, and the particle size of the NSC-g-PEI-LA/DNA complexes were between 150 and 400 nm as determined by a Zeta sizer. The NSC-g-PEI-LA/DNA complexes observed by scanning electron microscopy (SEM) exhibited a compact and spherical morphology. The zeta potentials of these complexes were increased with the weight ratio of NSC-g-PEI-LA/DNA. NSC-g-PEI-LA has a lower cytotoxicity than PEI (25 kDa) and the toxicity decreased with increasing substitution of LA. The transfection efficiency of different complexes was evaluated by luciferase assay. Compared with PEI (25 kDa) and NSC-g-PEI/DNA, NSC-g-PEI-LA showed good transfection activity and cell specificity to HepG2 cells. The results suggested that NSC-g-PEI-LA has the potential to be used as a safe and effective targeting gene vector. PMID:20957247

  15. Flocculation of Escherichia coli using a quaternary ammonium salt grafted carboxymethyl chitosan flocculant.

    PubMed

    Yang, Zhen; Degorce-Dumas, Jean-Regis; Yang, Hu; Guibal, Eric; Li, Aimin; Cheng, Rongshi

    2014-06-17

    Only few studies are available on bacteria removal efficiencies and antibacterial properties of flocculants, which is one of the important requirements in water treatment work. Escherichia coli (E. coli) was selected as an example of a Gram-negative bacteria for testing the flocculating properties of a quaternary ammonium salt grafted chitosan (carboxymethyl chitosan-graft-poly[(2-methacryloyloxyethyl) trimethylammonium chloride] copolymer; i.e., CMC-g-PDMC). The effect of various flocculation parameters, including flocculant dosage, initial bacterial density, nutrient medium content, and pH were successively investigated. The experimental results indicated that, besides flocculation effects, CMC-g-PDMC also exhibited a bactericidal effect (not requiring additional treatment facilities). Moreover, the flocculation mechanisms were investigated via zeta potential measurements, floc observation, and three-dimensional excitation-emission matrix spectra analysis. Apart from its flocculating and settling effect, this chitosan-based material has bactericidal action through the breaking of bacterial cell walls by grafted quaternary ammonium salt. PMID:24871697

  16. Characterization and bacterial adhesion of chitosan-perfluorinated acid films.

    PubMed

    Bierbrauer, Karina L; Alasino, Roxana V; Muñoz, Adrián; Beltramo, Dante M; Strumia, Miriam C

    2014-02-01

    We reported herein the study and characterization of films obtained by casting of chitosan solutions in perfluorinated acids, trifluoroacetic (TFA), perfluoropropionic (PFPA), and perfluorooctanoic (PFOA). The films were characterized by FTIR, solid state (13)C NMR, X-ray, AFM, contact angle, thermogravimetric effluent analysis by mass spectrometry, and rheology. The results showed a marked influence of chain length of the perfluorinated acids on the hydrophobic/hydrophilic ratio of the modified chitosan films which was evidenced by the different characteristics observed. The material that showed greater surface stability was chitosan-PFOA. Chitosan film with the addition of PFOA modifier became more hydrophobic, thus water vapor permeability diminished compared to chitosan films alone, this new material also depicted bacterial adhesion which, together with the features already described, proves its potential in applications for bioreactor coating. PMID:24189195

  17. Elucidation on enhanced application of synthesised kojic acid immobilised magnetic and chitosan tri-polyphosphate nanoparticles as antibacterial agents.

    PubMed

    Chaudhary, Jignesh; Lakhawat, Sudarshan; Pathak, Amrendra Nath

    2015-12-01

    Kojic acid (KA) is a secondary metabolite which is secreted by several aspergillus species. It is a multi-functional skeleton from which many derivatives can be synthesised and applied in various areas of biotechnology. KA grafting on synthesised magnetic nanoparticles (MNPs) and chitosan tri-polyphosphate (chitosan-TPP) nanoparticles was successfully done and characterised by Fourier transformation infrared spectroscopy. It was observed that amino propyl triethoxy silane-coated MNPs and chitosan-TPP nanoparticles enhanced the antibacterial activity of KA against both Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa). The organic constitution and significant antibacterial activity of KA-chitosan-TPP nanoparticles can be applicable in the field of medical biotechnology. PMID:26647814

  18. Preparation and characterization of poly(2-acrylamido-2-methylpropane-sulfonic acid)/Chitosan hydrogel using gamma irradiation and its application in wastewater treatment

    NASA Astrophysics Data System (ADS)

    Gad, Y. H.

    2008-09-01

    Radiation grafting of chitosan with 2-acrylamido-2-methyl propane sulfonic acid (AMPS) has been successfully performed. The effect of absorbed dose (kGy) and the chitosan:AMPS ratio on graft hydrogelization was studied. The structure of the prepared hydrogel was confirmed using infrared spectroscopy (IR). Thermal properties were simultaneously studied by thermogravimetric analysis (TGA). The effect of the polymerization variables on the swelling % of the prepared hydrogel was investigated. The highest equilibrium degree of swelling (38.6 g/g) and gel % (94.7%) of the prepared chitosan-AMPS hydrogel was at 40% AMPS and absorbed dose of 10 kGy. The removal of methylene blue, acid red dye, Cd (II) and Cr (III) from composed wastewater was also investigated. The effect of pH, the chitosan:AMPS ratio and the concentration of the pollutant on the adsorption process were studied.

  19. Safety evaluation of chitosan and chitosan acid salts from Panurilus argus lobster.

    PubMed

    Lagarto, Alicia; Merino, Nelson; Valdes, Odalys; Dominguez, Jesus; Spencer, Evelyn; de la Paz, Nilia; Aparicio, Guillermo

    2015-01-01

    Chitosan is a natural polymer with excellent properties such as biocompatibility, biodegradability, non-toxicity and adsorptive abilities. We obtained chitosan derived from Panurilus argus lobster shell and its lactate and acetate salts to introduce in pharmaceutical industry. We examined the single and repeated dose toxicity of chitosan and its lactate and acetate salts. Single oral doses of 2000 mg/kg were well tolerated for all three materials. In the repeat dose tests, animals treated with chitosan only show a slight erythrocytes increase. Variations in erythrocyte and leukocyte count and some biochemical parameters were observed in animals treated with chitosan acid salts. One g/kg orally was found to be the subacute NOAEL for chitosan due to the hematological findings observed were not considered adverse. Chitosans obtained from Panurilus argus lobster shell have low toxicity and may be safe in rats because it did not cause any lethality or changes in the general behavior in both the single and repeated dose toxicity studies. PMID:25450835

  20. Enhancing antibacterial activity of surface-grafted chitosan with immobilized lysozyme on bioinspired stainless steel substrates.

    PubMed

    Yuan, Shaojun; Yin, Jia; Jiang, Wei; Liang, Bin; Pehkonen, S O; Choong, Cleo

    2013-06-01

    Bacterial infections have been widely recognized as a major cause of the failure of medical implants and devices. One promising strategy to reduce the incidence of infections is to impart the material surfaces with bactericidal function for inhibiting bacterial adhesion and biofilm formation. In this study, stainless steel (SS) surface was first activated by a biomimetic dopamine anchor to provide active amino groups, followed by covalently immobilizing chitosan (CS) with glutaraldehyde (GA) as a bifunctional linker. Hen egg white lysozyme, a natural defensive enzyme, was finally conjugated to the grafted chitosan to enhance biocidal functionality. The antibacterial assay results demonstrated substantial enhancement in bactericidal efficiency against Staphylococcus aureus (S. aureus) on the lysozyme-immobilized SS substrates under the neutral pH conditions as compared to the chitosan-grafted SS substrates. With the inherent advantages of robust anchoring ability of dopamine and specific functionality of lysozyme, the metallic substrates can be readily tailored with antibacterial property to combat biomaterial-centered infection for potential biomedical applications. PMID:23434686

  1. Ibuprofen microencapsulation within acrylamide-grafted chitosan and methylcellulose interpenetrating polymer network microspheres: Synthesis, characterization, and release studies.

    PubMed

    Bulut, Emine

    2016-06-01

    This study deals with the development of interpenetrating polymer network (IPN) microspheres of acrylamide (AAm) grafted onto a chitosan (CS) backbone and methylcellulose (MC). Chitosan-graft-polyacrylamide (CS-g-PAAm) was synthesized by cerium (IV) ammonium nitrate-induced free radical graft polymerization. The grafting percentage was found to be 50.58%. The synthesized graft copolymer and MC were used to prepare microspheres by the water-in-oil (w/o) emulsion-crosslinking method, and crosslinked with glutaraldehyde (GA) as drug delivery matrices of ibuprofen (IBU). The release of IBU from microspheres decreased when the amount of CS-g-PAAm in the polymer matrix and amount of crosslinker added were increased, while it increased with the increase of the IBU/polymer ratio. PMID:25749277

  2. Brain-targeting study of stearic acid–grafted chitosan micelle drug-delivery system

    PubMed Central

    Xie, Yi-Ting; Du, Yong-Zhong; Yuan, Hong; Hu, Fu-Qiang

    2012-01-01

    Purpose Therapy for central nervous system disease is mainly restricted by the blood–brain barrier. A drug-delivery system is an effective approach to overcome this barrier. In this research, the potential of polymeric micelles for brain-targeting drug delivery was studied. Methods Stearic acid–grafted chitosan (CS-SA) was synthesized by hydrophobic modification of chitosan with stearic acid. The physicochemical characteristics of CS-SA micelles were investigated. bEnd.3 cells were chosen as model cells to evaluate the internalization ability and cytotoxicity of CS-SA micelles in vitro. Doxorubicin (DOX), as a model drug, was physically encapsulated in CS-SA micelles. The in vivo brain-targeting ability of CS-SA micelles was qualitatively and quantitatively studied by in vivo imaging and high-performance liquid chromatography analysis, respectively. The therapeutic effect of DOX-loaded micelles in vitro was performed on glioma C6 cells. Results The critical micelle concentration of CS-SA micelles with 26.9% ± 1.08% amino substitute degree was 65 μg/mL. The diameter and surface potential of synthesized CS-SA micelles in aqueous solution was 22 ± 0.98 nm and 36.4 ± 0.71 mV, respectively. CS-SA micelles presented excellent cellular uptake ability on bEnd.3 cells, the IC50 of which was 237.6 ± 6.61 μg/mL. DOX-loaded micelles exhibited slow drug-release behavior, with a cumulative release up to 72% within 48 hours in vitro. The cytotoxicity of DOX-loaded CS-SA micelles against C6 was 2.664 ± 0.036 μg/mL, compared with 0.181 ± 0.066 μg/mL of DOX · HCl. In vivo imaging results indicated that CS-SA was able to transport rapidly across the blood–brain barrier and into the brain. A maximum DOX distribution in brain of 1.01%/g was observed 15 minutes after administration and maintained above 0.45%/g within 1 hour. Meanwhile, free DOX · HCl was not detected in brain. In other major tissues, DOX-loaded micelles were mainly distributed into lung, liver, and

  3. Genotoxicity effect, antioxidant and biomechanical correlation: experimental study of agarose-chitosan bone graft substitute in New Zealand white rabbit model.

    PubMed

    Jebahi, Samira; Ben Saleh, Ghada; Saoudi, Mongi; Besaleh, Salma; Oudadesse, Hassane; Mhadbi, Moufida; Rebai, Tarek; Keskes, Hassib; El Feki, Abdelfattah

    2014-08-01

    Bone loss associated with skeletal trauma or metabolic diseases often requires bone grafting. In such situations, a biomaterial is necessary for migrated cells to produce new tissue. In this study, agarose-chitosan was implanted in the femoral condyle of New Zealand White rabbits that were divided into three groups: Group I was used as control; Groups II and III were used as implanted tissue with agarose-chitosan and presenting empty defects, respectively. This study evaluated the agarose-chitosan biocompatibility by determining the in vivo genotoxicity, oxidative stress balance that correlated with the hardness mechanical property. Moreover, the histopathological and quantitative elements analyzed by using inductively coupled plasma optical emission spectrometry were determined. After 30 days of implantation, the in vivo analysis of genotoxicity showed that agarose-chitosan did not induce chromosome aberration or micronucleus damage. A significant decrease in thiobarbituric and acid-reactive substance was observed after agarose-chitosan implantation in the bone tissue. Superoxide dismutase, catalase and glutathione peroxidase were significantly enhanced in agarose-chitosan-treated group compared with that of control group. A negative correlation coefficient of the mechanical property with malonyldialdehyde level was detected (R = -0.998). The histological study exhibited a significantly increased angiogenesis and newly formed tissue. No presence of inflammatory process, necrotic or fibrous tissue was detected. Major and trace elements such as Ca, P, Zn, Mg and Fe were increased significantly in the newly formed bone. These findings show that agarose-chitosan biomaterial implantation might be effective for treating trauma and bone regeneration. PMID:25205747

  4. Gene Expression and Pulmonary Toxicity of Chitosan-graft- Polyethylenimine as Aerosol Gene Carrier.

    PubMed

    Kwon, Jung-Taek; Jiang, Hu-Lin; Minai-Tehrani, Arash; Gyu Woo, Chang; Choi, Mansoo; Cho, Chong-Su; Kim, Yeon-Soo; Cho, Myung-Haing

    2013-01-01

    Chitosan-graft-polyethylenimine (CHI-g-PEI) copolymer has been used for the improvement of low transfection efficiency of chitosan. The present study aims to test the pulmonary toxicity and efficiency of CHI-g-PEI as an aerosol gene carrier. Mice were exposed to aerosol containing green-fluorescent protein (GFP)-polyethylenimine (PEI) or GFP-CHI-g-PEI complexes for 30 min during the development of our nose-only exposure chamber (NOEC) system. CHI-g-PEI-mediated aerosol delivery demonstrated 15.65% enhancement of the fluorescence intensity. Compared to PEI, CHI-g-PEI showed no significant pulmonary toxicity. In summary, using CHI-g-PEI is safe and shows high transfection in aerosol gene delivery to animals, and enhanced efficiency was achieved through our aerosol gene delivery system. Therefore, CHI-g-PEI and this system would be applicable to future study for aerosol gene therapy. PMID:24250601

  5. Improvement in physical and biological properties of chitosan/soy protein films by surface grafted heparin.

    PubMed

    Wang, Xiaomei; Hu, Ling; Li, Chen; Gan, Li; He, Meng; He, Xiaohua; Tian, Weiqun; Li, Mingming; Xu, Li; Li, Yinping; Chen, Yun

    2016-02-01

    A series of chitosan/soy protein isolate (SPI) composite films (CS-n, n=0, 10 and 30, corresponding to SPI content in the composites) were prepared. Heparin was grafted onto the surface of CS-n to fabricate a series of heparinized films (HCS-n). CS-n and HCS-n were characterized by ATR-Fourier transform infrared spectroscopy and water contact angle. The surface heparin density was measured by toluidine blue assay. The results showed that heparin has been successfully grafted onto the surface of CS-n. Heparin evenly distributed on the surface of the films and the heparin content increased with the increase of SPI content, and the hydrophilicity of the films was enhanced due to the grafted heparin. The cytocompatibility and hemocompatibility of CS-n and HCS-n were evaluated by cell culture (MTT assay, live/dead assay, cell morphology and cell density observation), platelet adhesion test, plasma recalcification time (PRT) measurement, hemolysis assay and thrombus formation test. HCS-n showed higher cell adhesion rate and improved cytocompatibility compared to the corresponding CS-n. HCS-n also exhibited lower platelet adhesion, longer PRT, higher blood anticoagulant indexes (BCI) and lower hemolysis rate than the corresponding CS-n. The improved cytocompatibility and hemocompatibility of HCS-n would shed light on the potential applications of chitosan/soy protein-based biomaterials that may come into contact with blood. PMID:26616450

  6. Preparation, blood coagulation and cell compatibility evaluation of chitosan-graft-polylactide copolymers.

    PubMed

    Wang, Qi; Liu, Pei; Liu, Peifeng; Gong, Tao; Li, Suming; Duan, Yourong; Zhang, Zhirong

    2014-02-01

    Biodegradable chitosan-graft-polylactide (PLA-CS) copolymers were prepared by the grafting of a poly(L-lactide) (PLLA) or poly(D-lactide) (PDLA) precursor to the backbone of chitosan using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC ⋅ HCl) and N-hydroxysuccinimide (NHS) as a coupling agent. The blood and cell compatibility of the graft copolymers were investigated in comparison to PLLA and PDLA homopolymers. The coagulation properties of PLA-CS were evaluated by hemolysis, plasma recalcification, dynamic blood clotting and protein absorption assays. PLA-CS copolymers present similar hemolysis ratio and plasma recalcification time as PLA, but slower dynamic blood clotting and lower protein absorption. The cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), agar diffusion and lactate dehydrogenase (LDH) experiments. All the samples presented no effect on the viability to cells. Inflammatory cytokine analysis using sandwich ELISAs revealed that PLA-CS would not stimulate inflammatory activity. PMID:24448591

  7. The effect of collagen-chitosan porous scaffold thickness on dermal regeneration in a one-stage grafting procedure.

    PubMed

    Haifei, Shi; Xingang, Wang; Shoucheng, Wu; Zhengwei, Mao; Chuangang, You; Chunmao, Han

    2014-01-01

    Dermal substitutes are used as dermal regeneration templates to reduce scar formation and improve wound healing. Unlike autografts, dermal substitutes lack normal vascular networks. The increased distance required for diffusion of oxygen and nutrients to the autograft following interpositioning of the substitute dramatically affects graft survival. To evaluate the effect of collagen-chitosan scaffold thickness on dermal regeneration, single-layer collagen-chitosan porous scaffolds of 0.5-, 1- and 2-mm thicknesses were fabricated and used to treat full-thickness wounds in a one-stage grafting procedure in a rat model. Skin-graft viability, wound contraction, histological changes, and wound tensile strength were evaluated. The results indicated that the distance for the diffusion of oxygen and nutrients to the autograft in the 2-mm-thick scaffold provided less support for graft take, which resulted in graft necrosis, extensive inflammatory reaction, marked foreign-body reaction (FBR), rapid scaffold degradation, and abnormal collagen deposition and remodeling. In contrast, the thinner scaffolds, especially of that 0.5-mm thickness, promoted earlier angiogenesis, ensuring skin-graft viability with a mild FBR, and ordered fibroblast infiltration and better collagen remodeling. It can be concluded that collagen-chitosan porous scaffolds with a thickness of <1mm are more suitable for dermal regeneration and can be used as dermal templates for treatment of dermal defects using a one-stage grafting procedure. PMID:24076783

  8. Synthesis, characterization and antimicrobial activity of biodegradable conducting polypyrrole-graft-chitosan copolymer

    NASA Astrophysics Data System (ADS)

    Cabuk, Mehmet; Alan, Yusuf; Yavuz, Mustafa; Unal, Halil Ibrahim

    2014-11-01

    In this study, polypyrrole-graft-chitosan (PPy-g-CS) copolymer was chemically synthesized and its structural and morphological properties characterized by FTIR, UV-vis, SEM, XRD, TGA and zeta-potential techniques. The results revealed that there were strong interactions between PPy and CS chains. The electrical conductivity of CS increased to semiconducting range by grafting. The crystallinity and thermal stability of PPy-g-CS copolymer improved when compared to CS. The copolymer was tested against various bacterial and fungal strains at various concentrations and results obtained were compared with the reference antibiotics. The results indicated that the antibacterial activity of PPy-g-CS copolymer was stronger than CS and PPy alone. The antibacterial activity of the PPy-g-CS copolymer observed to increase with rising concentration, and showed stronger activity against bacteria than Penicillin (10 mg), Rifampicin (5 mg) and Trimethoprim (25 mg), whereas showed equipotent activity with Amikacin (30 mg) and Erythromycin (15 mg) antibiotics.

  9. Ultraviolet-assisted synthesis of polyacrylamide-grafted chitosan nanoparticles and flocculation performance.

    PubMed

    Ma, Jiangya; Fu, Kun; Shi, Jun; Sun, Yongjun; Zhang, Xinxi; Ding, Lei

    2016-10-20

    In the present work, a new flocculant, polyacrylamide-grafted chitosan nanoparticles (NCS-g-PAM), was synthesized by the copolymerization of acrylamide (AM) and chitosan nanoparticle (NCS) under ultraviolet irradiation using 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone as photo-initiator. The NCS was prepared by the ionic gelation between chitosan and sodium tripolyphosphate. The structure and morphology of NCS-g-PAM were characterized by Fourier Transform Infraredspectroscopy (FT-IR), X-ray diffraction, (1)H-nuclear magnetic resonance spectrometry, scanning electron microscopy, and thermogravimetric analysis. The factors affecting the intrinsic viscosity and the yield of copolymer were studied, which showed that the optimum conditions for the synthesis of NCS-g-PAM were mAM:mNCS=8:1, 0.15g of initiator dosage, mCS:mTPP=4.5:1, 1min of ultrasonication time, 4h of illumination time, and 30min of stirring time. The NCS-g-PAM was found to be more effective than NC-g-PAM in the flocculation of both kaolin suspension and Cu(2+) simulated wastewater. With 5mg/L of polyaluminium chloride (PAC) coordinated and 1mg/L of NCS-g-PAM it was confirmed to be appropriate for flocculating kaolin suspension. PMID:27474601

  10. Photo-initiated grafting of gelatin/N-maleic acyl-chitosan to enhance endothelial cell adhesion, proliferation and function on PLA surface.

    PubMed

    Zhu, Aiping; Zhao, Feng; Ma, Teng

    2009-07-01

    Vascular graft surface properties significantly affect adhesion, growth and function of endothelial cells (ECs). The bulk degradation property of poly(lactic acid) (PLA) makes it possible for it to be replaced by cellular materials and PLA is desirable as a scaffold material for vascular grafts. However, PLA has an unfavorable surface property for EC adhesion and proliferation due to the lack of a selective cell adhesion motif. Photo-initiated surface-grafting polymerization is a promising method for immobilizing certain biomacromolecules on material surfaces without compromising bulk properties. N-Maleic acyl-chitosan (NMCS) is a novel biocompatible amphiphilic derivative of chitosan with double bonds and can be initiated by ultraviolet light. In this study, gelatin was complexed with NMCS via hydrophobic interaction, and gel/NMCS complex thus formed was then grafted on the PLA surface to improve EC biocompatibility. X-ray photoelectron and Fourier transform infrared spectroscopy, and water contact angle measurement confirmed immobilization of the gel/NMCS complex on PLA surface. Moreover, the gel/NMCS modified PLA enhanced human umbilical vein endothelial cell (HUVEC) spreading and flattening, and promoted the expression of more structured CD31 and vWF compared to unmodified PLA film. Compared to the unmodified PLA surface, the HUVECs on the modified PLA surface had elevated uptake of acetylated low-density lipoprotein, and maintained the ability to modulate metabolic activity upon exposure to shear stress at 5dyncm(-2) by up-regulating nitric oxide and prostacyclin production. Cell retention was 1.6 times higher on the gel/NMCS-PLA surface, demonstrating its improved potential for hemocompatibility. These results indicate that photo-initiated surface-grafting of the biomimetic gel/NMCS complex is an effective method to modify material surfaces as vascular grafts. PMID:19299215

  11. High internal phase emulsion templating with self-emulsifying and thermoresponsive chitosan-graft-PNIPAM-graft-oligoproline.

    PubMed

    Oh, Bernice H L; Bismarck, Alexander; Chan-Park, Mary B

    2014-05-12

    High internal phase emulsion (HIPE)-templating is an attractive method of producing high porosity polymer foams with tailored pore structure, pore size and porosity. However, this method typically requires the use of large amounts of surfactants to stabilize the immiscible liquid phases, and polymerizable monomers/cross-linker in the continuous minority phase to solidify the HIPE, which may not be desirable in many applications. We show that polyHIPEs with a porosity of 73% can be formed solely using a copolymer of chitosan-graft-PNIPAM-graft-oligoproline (CSN-PRO), which acts simultaneously as emulsifier and thermoresponsive gelator, and forms upon removal of the liquid templating phases, the bulk structure of the resulting polyHIPE. With only a small amount of surfactant (1%v/v in the aqueous phase), and varying the polymer concentration and internal phase volume ratio, different polyHIPEs with porosities of up to 99%, surface areas in excess of 300 m(2)/g and controlled pore interconnectivity can be formed. The poly(CSN-PRO)HIPEs are also shown to be thermoresponsive and remained intact when immersed into water above 34 °C but dissolve below their LCST, which is useful for applications such as drug delivery and tissue engineering scaffolds. PMID:24661070

  12. Phenylboronic Acid-Mediated Tumor Targeting of Chitosan Nanoparticles

    PubMed Central

    Wang, Xin; Tang, Huang; Wang, Chongzhi; Zhang, Jialiang; Wu, Wei; Jiang, Xiqun

    2016-01-01

    The phenylboronic acid-conjugated chitosan nanoparticles were prepared by particle surface modification. The size, zeta potential and morphology of the nanoparticles were characterized by dynamic light scattering, zeta potential measurement and transmission electron microscopy. The cellular uptake, tumor penetration, biodistribution and antitumor activity of the nanoparticles were evaluated by using monolayer cell model, 3-D multicellular spheroid model and H22 tumor-bearing mice. The incorporation of phenylboronic acid group into chitosan nanoparticles impart a surface charge-reversible characteristic to the nanoparticles. In vitro evaluation using 2-D and 3-D cell models showed that phenylboronic acid-decorated nanoparticles were more easily internalized by tumor cells compared to non-decorated chitosan nanoparticles, and could deliver more drug into tumor cells due to the active targeting effect of boronic acid group. Furthermore, the phenylboronic acid-decorated nanoparticles displayed a deeper penetration and persistent accumulation in the multicellular spheroids, resulting in better inhibition growth to multicellular spheroids than non-decorated nanoparticles. Tumor penetration, drug distribution and near infrared fluorescence imaging revealed that phenylboronic acid-decorated nanoparticles could penetrate deeper and accumulate more in tumor area than non-decorated ones. In vivo antitumor examination demonstrated that the phenylboronic acid-decorated nanoparticles have superior efficacy in restricting tumor growth and prolonging the survival time of tumor-bearing mice than free drug and drug-loaded chitosan nanoparticles. PMID:27375786

  13. Phenylboronic Acid-Mediated Tumor Targeting of Chitosan Nanoparticles.

    PubMed

    Wang, Xin; Tang, Huang; Wang, Chongzhi; Zhang, Jialiang; Wu, Wei; Jiang, Xiqun

    2016-01-01

    The phenylboronic acid-conjugated chitosan nanoparticles were prepared by particle surface modification. The size, zeta potential and morphology of the nanoparticles were characterized by dynamic light scattering, zeta potential measurement and transmission electron microscopy. The cellular uptake, tumor penetration, biodistribution and antitumor activity of the nanoparticles were evaluated by using monolayer cell model, 3-D multicellular spheroid model and H22 tumor-bearing mice. The incorporation of phenylboronic acid group into chitosan nanoparticles impart a surface charge-reversible characteristic to the nanoparticles. In vitro evaluation using 2-D and 3-D cell models showed that phenylboronic acid-decorated nanoparticles were more easily internalized by tumor cells compared to non-decorated chitosan nanoparticles, and could deliver more drug into tumor cells due to the active targeting effect of boronic acid group. Furthermore, the phenylboronic acid-decorated nanoparticles displayed a deeper penetration and persistent accumulation in the multicellular spheroids, resulting in better inhibition growth to multicellular spheroids than non-decorated nanoparticles. Tumor penetration, drug distribution and near infrared fluorescence imaging revealed that phenylboronic acid-decorated nanoparticles could penetrate deeper and accumulate more in tumor area than non-decorated ones. In vivo antitumor examination demonstrated that the phenylboronic acid-decorated nanoparticles have superior efficacy in restricting tumor growth and prolonging the survival time of tumor-bearing mice than free drug and drug-loaded chitosan nanoparticles. PMID:27375786

  14. Immobilization of catalase on chitosan and amino acid- modified chitosan beads.

    PubMed

    Başak, Esra; Aydemir, Tülin

    2013-08-01

    Bovine liver catalase was covalently immobilized onto amino acid-modified chitosan beads. The beads were characterized with SEM, FTIR, TGA and the effects of immobilization on optimum pH and temperature, thermostability, reusability were evaluated. Immobilized catalase showed the maximal enzyme activity at pH 7.0 at 30°C. The kinetic parameters, Km and Vmax, for immobilized catalase on alanine-chitosan beads and lysine-chitosan beads were estimated to be 25.67 mM, 27 mM and 201.39 μmol H2O2/min, 197.50 μmol H2O2/min, respectively. The activity of the immobilized catalase on Ala-CB and Lys-CB retained 40% of its high initial activity after 100 times of reuse. PMID:23316810

  15. Defluoridation of water using dicarboxylic acids mediated chitosan-polyaniline/zirconium biopolymeric complex.

    PubMed

    Muthu Prabhu, Subbaiah; Meenakshi, Sankaran

    2016-04-01

    The present investigation describes the preparation of hydrogen bonded chitosan-polyaniline/zirconium biopolymeric matrix by grafting method under dicarboxylic acid medium for the removal of fluoride, first time. Herein, the dicarboxylic acids, oxalic acid, malonic acid, succinic acid were used as medium. The synthesized complex was characterized by usual analytical techniques like FTIR, XRD, SEM and EDAX analysis. From the batch equilibrium experiments, the maximum defluoridation capacity (DC) was found to be 8.713 mg/g at room temperature with the minimum contact time of 24 min at 100mg of the sorbent dosage. The temperature study results of adsorption kinetics showed the adsorption behavior could be better described by the pseudo-second-order equation than pseudo-first-order kinetic model. The adsorption isotherm was well fitted by the Freundlich equation rather than Langmuir and D-R isotherms. The mechanism of fluoride removal was ligand exchange at neutral pH and electrostatic attraction at acidic pH of the medium. Regeneration studies were carried out to identify the best regenerant which makes the process cost-effective. Conclusions of this work demonstrate the potential applicability of the dicarboxylic acid mediated chitosan-polyaniline/zirconium complex as an effective adsorbent for fluoride removal from water. PMID:26706844

  16. Chitosan-based microcapsules containing grapefruit seed extract grafted onto cellulose fibers by a non-toxic procedure.

    PubMed

    Alonso, Diana; Gimeno, Miquel; Sepúlveda-Sánchez, José D; Shirai, Keiko

    2010-04-19

    A novel non-toxic procedure is described for the grafting of chitosan-based microcapsules containing grapefruit seed oil extract onto cellulose. The cellulose was previously UV-irradiated and then functionalized from an aqueous emulsion of the chitosan with the essential oil. The novel materials are readily attained with durable fragrance and enhanced antimicrobial properties. The incorporation of chitosan as determined from the elemental analyses data was 16.08+/-0.29 mg/g of sample. Scanning electron microscopy (SEM) and gas chromatography-mass spectroscopy (GC-MS) provided further evidence for the successful attachment of chitosan microcapsules containing the essential oil to the treated cellulose fibers. The materials thus produced displayed 100% inhibition of Escherichia coli and Staphylococcus epidermidis up to 48 h of incubation. Inhibition of bacteria by the essential oil was also evaluated at several concentrations. PMID:20167308

  17. Synthesis, characterization and cytotoxicity of poly(ethylene glycol)-graft-trimethyl chitosan block copolymers.

    PubMed

    Mao, Shirui; Shuai, Xintao; Unger, Florian; Wittmar, Matthias; Xie, Xiulan; Kissel, Thomas

    2005-11-01

    PEGylated trimethyl chitosan (TMC) copolymers were synthesized in an attempt to both increase the solubility of chitosan in water, and improve the biocompatibility of TMC. A series of copolymers with different degrees of substitution were obtained by grafting activated poly(ethylene glycol)s (PEG) of different MW onto TMC via primary amino groups. Structure of the copolymers was characterized using 1H, 13C NMR spectroscopy and GPC. Solubility experiments demonstrated that PEG-g-TMC copolymers were completely water-soluble over the entire pH range of 1-14 regardless of the PEG MW, even when the graft density was as low as 10%. Using the methyl tetrazolium (MTT) assay, the effect of TMC molecular weight, PEGylation ratio, PEG and TMC molecular weight in the copolymers, and complexation with insulin on the cytotoxicity of TMC was examined, and IC50 values were calculated with L929 cell line. All polymers exhibited a time- and dose-dependent cytotoxic response that increased with molecular weight. PEGylation can decrease the cytotoxicity of TMC to a great extent in the case of low molecular weight TMCs. According to the cytotoxicity results, PEG 5 kDa is superior for PEGylation when compared to PEG 550 Da at similar graft ratios. Complexation with insulin further increased cell viability. In addition, Lactate dehydrogenase (LDH) assays were performed to quantify the membrane-damaging effects of the copolymers, which is in line with the conclusion drawn from MTT assay. Moreover, the safety of the copolymers was corroborated by observing the morphological change of the cells with inverted phase contrast microscopy. Based upon these results PEG-g-TMC merits further investigations as a drug delivery vehicle. PMID:15913769

  18. Enhanced biocompatibility and antibacterial property of polyurethane materials modified with citric acid and chitosan.

    PubMed

    Liu, Tian-Ming; Wu, Xing-Ze; Qiu, Yun-Ren

    2016-08-01

    Citric acid (CA) and chitosan (CS) were covalently immobilized on polyurethane (PU) materials to improve the biocompatibility and antibacterial property. The polyurethane pre-polymer with isocyanate group was synthesized by one pot method, and then grafted with citric acid, followed by blending with polyethersulfone (PES) to prepare the blend membrane by phase-inversion method so that chitosan can be grafted from the membrane via esterification and acylation reactions eventually. The native and modified membranes were characterized by attenuated total reflectance-Fourier transform infrared spectroscope, X-ray photoelectron spectroscopy, scanning electron microscopy, water contact angle measurement, and tensile strength test. Protein adsorption, platelet adhesion, hemolysis assay, activated partial thromboplastin time, prothrombin time, thrombin time, and adsorption of Ca(2+) were executed to evaluate the blood compatibility of the membranes decorated by CA and CS. Particularly, the antibacterial activities on the modified membranes were evaluated based on a vitro antibacterial test. It could be concluded that the modified membrane had good anticoagulant property and antibacterial property. PMID:27102367

  19. pH sensitive N-succinyl chitosan grafted polyacrylamide hydrogel for oral insulin delivery.

    PubMed

    Mukhopadhyay, Piyasi; Sarkar, Kishor; Bhattacharya, Sourav; Bhattacharyya, Aditi; Mishra, Roshnara; Kundu, P P

    2014-11-01

    pH sensitive PAA/S-chitosan hydrogel was prepared using ammonium persulfate (APS) as an initiator and methylenebisacrylamide (MBA) as a crosslinker for oral insulin delivery. The synthesized copolymer was characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) study; morphology was observed under scanning electron microscope (SEM). The PAA/S-chitosan with ∼ 38% of insulin loading efficiency (LE) and ∼ 76% of insulin encapsulation efficiency (EE), showed excellent pH sensitivity, retaining ∼ 26% of encapsulated insulin in acidic stomach pH 1.2 and releasing of ∼ 98% of insulin in the intestine (pH 7.4), providing a prolonged attachment with the intestinal tissue. The oral administration of insulin loaded PAA/S-chitosan hydrogel was successful in lowering the blood glucose level of diabetic mice. The bioavailability of insulin was ∼ 4.43%. Furthermore, no lethality or toxicity was documented after its peroral administration. Thus, PAA/S-chitosan hydrogel could serve as a promising oral insulin carrier in future. PMID:25129792

  20. Synthesis and characterization of thermo- and pH- sensitive hydrogels based on Chitosan-grafted N-isopropylacrylamide via γ-radiation

    NASA Astrophysics Data System (ADS)

    Cai, Hong; Zhang, Zheng Pu; Chuan Sun, Ping; Lin He, Bing; Xia Zhu, Xiao

    2005-09-01

    Thermo- and pH-sensitive hydrogels were prepared by graft copolymerization of chitosan (CS) and N-isopropylacrylamide via γ-radiation. The effects of monomer concentration and irradiation dose on grafting percentage and grafting efficiency were studied. The graft copolymers were characterized by 13C CP/MAS NMR and thermogravimetric analysis. The pH and thermosensitivity and swelling properties of the hydrogels were investigated. The results showed that the grafting percentage and grafting efficiency increased with the increase of monomer concentration and total irradiation dose. The highest grafting percentage is 620%, the lower critical solution temperature (LCST) of this hydrogel is about 28 °C.

  1. Transglutaminase catalyzed hydrolyzed wheat gliadin grafted with chitosan oligosaccharide and its characterization.

    PubMed

    Jiang, Wen; Zhou, Zhiming; Wang, Dan; Zhou, Xiaohua; Tao, Renyou; Yang, Yang; Shi, Yexin; Zhang, Guiluo; Wang, Deyi; Zhou, Zhen

    2016-11-20

    Chitosan oligosaccharide (COS) was grafted on hydrolyzed wheat gliadin (HWG) with microbial transglutaminase (MTGase) as catalyst. The grafting reaction exhibited the best performance when it was done under the optimum temperature 50°C for 50min with HWG/COS mass ratio of 40:1, pH 6.00-6.50. The maximum grafting rate of COS was 64.83% at this condition. The chemical structure characterizations of HWG-COS performed by FTIR, (13)C NMR, X-ray diffractometry and TGA-DTG illustrated that amino groups in COS had participated in the formations of the amino band during the synthesis. HPLC and GFC analysis showed that HWG-COS had two main components, which together accounted for 80.64% of the total polymer and the molecular weight of the two components was 61.77kDa and 27.29kDa, respectively. HWG-COS was undissolved in water and many organic solvent, slightly soluble in 1% NaOH, with a solubility of 1.84mg/L. In antibacterial activity test, HWG-COS showed the best antimicrobial properties to Salmonella enteriditis, with an antibacterial activity improved by 41.74%. PMID:27561477

  2. Cross-linking of succinate-grafted chitosan and its effect on the capability to adsorb Pb(II) ion

    NASA Astrophysics Data System (ADS)

    Masykur, Abu; Juari Santosa, Sri; Jumina, Dwi Siswanta dan

    2016-02-01

    The aim of this research was to improve the adsorption capacity of chitosan by modification of the chitosan using various cross-linking agents and followed by grafting using succinate anhydride. Succinate anhydride was grafted into chitosan that had been cross-linked using ethylene glycol di-glycidyl ether (EGDE), diethylene glycol diglycidyl ether (DEGDE) andbisphenolAdiglycidyl ether (BADGE) on the hydroxyl group of chitosan to yield Chit- EGDE-Suc, Chit-DEGDE-Suc, and Chit-BADGE-Suc, respectively. Modified chitosans were analyzed using FTIR and TG-DTA and then applied as adsorbents for Pb(II) ion. Adsorption was carried out in batch condition with a variation of solution pH, contact time, and concentration of Pb(II) in the solution. Adsorption ofPb(II) ion reached optimum condition at pH 5 and contact time of 120 minutes. Adsorption of Pb(II) ion on all of the adsorbents fit well the pseudo-second order kinetic equation. Adsorption capacities of Pb(II) on Chit-EGDE-Suc, Chit-DEGDE-SucdanChit-BADGE-Suc were 0.333, 0.388 and 0.898 mmolg-1, respectively, which mean that the adsorption of Chit-BADGE-Suc was the highest and followed by Chit- DEGDE-Suc and Chit-EGDE-Suc.

  3. Preparation of carboxymethyl chitosan-graft-β-cyclodextrin modified silica gel and preconcentration of cadmium.

    PubMed

    Lü, Haixia; An, Hongtao; Wang, Xiaoming; Xie, Zenghong

    2013-10-01

    Carboxymethyl chitosan (CMCS) grafted with β-cyclodextrin (CMCS-g-CD) modified silica gel as a new solid phase extraction (SPE) adsorbent for cadmium has been developed. The optimum batch experimental conditions (pH, amount of adsorbent and contact time) and column experimental conditions (concentration and volume of elution solution) were optimized, respectively. The kinetic models for Cd (II) were investigated and the results indicated that pseudo-second-order equation provided a better R(2) (R(2)>0.999) and agreement between calculated Qe value (10.6 mg/g) and the experimental Qe (exp) value (11.3 mg/g). The developed method was successfully applied to the determination of Cd(II) in lake water and tap water with recoveries ranging from 96.0% to 102.0%. PMID:23921207

  4. Chitosan-graft-β-cyclodextrin nanoparticles as a carrier for controlled drug release.

    PubMed

    Yuan, Zeting; Ye, Yajing; Gao, Feng; Yuan, Huihui; Lan, Minbo; Lou, Kaiyan; Wang, Wei

    2013-03-25

    Chitosan (CS) grafted with β-cyclodextrin (CD-g-CS) nanoparticles as a new carrier for poorly water-soluble drugs has been developed. The CD-g-CS polymer is readily synthesized from chitosan and mono-6-deoxy-6-(p-toluenesulfonyl)-β-cyclodextrin. Three different degrees of substitution (DS) of β-cyclodextrin (β-CD) on CD-g-CS (9.6, 14.0 and 20.0%) are designed and evaluated by controlling the mole ratio of β-CD to chitosan. Then CD-g-CS nanoparticles are prepared by an ionic gelation method, with the controlled size of 202.0-589.0 nm. Stable colloidal dispersion of the nanoparticles has been formed with the zeta potential of +23.0 to +43.0 mV. In vitro stability test indicates that CD-g-CS nanoparticles are more stable in phosphate-buffered saline compared with CS nanoparticles. Finally, the poorly water-soluble drug, ketoprofen (KTP), is used as a model drug to evaluate the efficiency of the new drug delivery carrier. It is found that the encapsulation efficiency of KTP in the nanoparticles with 20% DS of CD is as high as 1.36-fold than that of CS nanoparticles. Moreover, notably KTP is released from the nanoparticles in a controlled-release manner and is pH-responsive on DS of CD. In summary, these results suggest that the CD-g-CS nanoparticles, as a general promising drug delivery system, can be used as a potential biodegradable nano-drug delivery system for controlled release of poorly water-soluble drugs with pH-responsive capability. PMID:23422276

  5. Characterization and osteogenic activity of a silicatein/biosilica-coated chitosan-graft-polycaprolactone.

    PubMed

    Wiens, Matthias; Elkhooly, Tarek A; Schröder, Heinz-Christoph; Mohamed, Tawheed H A; Müller, Werner E G

    2014-10-01

    Several attempts have been made in the past to fabricate hybrid materials that display the complementary properties of the polyester polycaprolactone (PCL) and the polysaccharide chitosan (CHS) for application in the field of bone regeneration and tissue engineering. However, such composites generally have no osteogenic activity per se. Here we report the synthesis of a chitosan-graft-polycaprolactone (CHS-g-PCL) and its subsequent characterization, including crystallinity, chemical structure and thermal stability. Upon surface-functionalization of CHS-g-PCL with osteogenic biosilica via the surface-immobilized enzyme silicatein, protein adsorption, surface morphology and wettability were assessed. Finally, the cultivation of osteoblastic SaOS-2 cells on the surface-functionalized CHS-g-PCL was followed by analyses of cell viability, mineral deposition and alkaline phosphatase activity. These characterizations revealed a composite that combines the versatile properties of CHS-g-PCL with the osteogenic activity of the silicatein/biosilica coating and, hence, represents an innovative alternative to conventionally used CHS/PCL composites for biomedical applications, where stable bone-material interfaces are required. PMID:24998774

  6. Prevention of peritendinous adhesions with electrospun chitosan-grafted polycaprolactone nanofibrous membranes.

    PubMed

    Chen, Shih-Hsien; Chen, Chih-Hao; Fong, Yi Teng; Chen, Jyh-Ping

    2014-12-01

    As one of the common complications after tendon injury and subsequent surgery, peritendinous adhesions could be minimized by directly placing a physical barrier between the injured site and the surrounding tissue. With the aim of solving the shortcomings of current biodegradable anti-adhesion barrier membranes, we propose the use of an electrospun chitosan-grafted polycaprolactone (PCL-g-CS) nanofibrous membrane (NFM) to prevent peritendinous adhesions. After introducing carboxyl groups on the surface by oxygen plasma treatment, the polycaprolactone (PCL) NFM was covalently grafted with chitosan (CS) molecules, with carbodiimide as the coupling agent. Compared with PCL NFM, PCL-g-CS NFM showed a similar fiber diameter, permeation coefficient for bovine serum albumin, ultimate tensile strain, reduced pore diameter, lower water contact angle, increased water sorption and tensile strength. With its submicrometer pore diameter (0.6-0.9μm), both NFMs could allow the diffusion of nutrients and waste while blocking fibroblast penetration to prevent adhesion formation after tendon surgery. Cell culture experiments verified that PCL-g-CS NFM can reduce fibroblast attachment while maintaining the biocompatibility of PCL NFM, implicating a synergistic anti-adhesion effect to raise the anti-adhesion efficacy. In vivo studies with a rabbit flexor digitorum profundus tendon surgery model confirmed that PCL-g-CS NFM effectively reduced peritendinous adhesion from gross observation, histology, joint flexion angle, gliding excursion and biomechanical evaluation. An injured tendon wrapped with PCL-g-CS NFM showed the same tensile strength as the naturally healed tendon, indicating that the anti-adhesion NFM will not compromise tendon healing. PMID:25192729

  7. Synthesis and characterization of pH tolerant and mucoadhesive (thiol-polyethylene glycol) chitosan graft polymer for drug delivery.

    PubMed

    Hauptstein, Sabine; Bonengel, Sonja; Griessinger, Julia; Bernkop-Schnürch, Andreas

    2014-02-01

    The objective of this study was to generate a water-soluble thiolated chitosan to enable the permeation-enhancing effect of chitosan at pH of at least 5.5 without losing the advantages of improved mucoadhesive properties. Therefore, the thiol-bearing polyoxyethylene ligand {O-(3-carboxylpropyl)-O'-[2-[3-mercaptopropionylamino)ethyl]-polyethyleneglycol} was conjugated via amide bond formation to the amino group of chitosan. Resulting novel chitosan derivative (Chito-PEG-SH) exhibited 250 μmol free thiol groups per gram polymer. By the attachment of the thiol-bearing PEG ligand, an improvement of permeation-enhancing effect on rat intestine (2.7-fold improvement) as well as on a Caco-2 monolayer model (1.9-fold improvement) could be found. Cytotoxicity studies on Caco-2 cells revealed no change in biocompatibility. Mucoadhesion was improved 3.1-fold by the formation of disulfide bonds with mucus glycoproteins. The mucoadhesive effect of Chito-PEG-SH turned out to be similar to thiolated chitosan and more pronounced than mucoadhesive properties of unmodified chitosan. The graft polymer is soluble in water and aqueous solutions over a broad pH range. In aqueous media, the novel polymer does not precipitate at pH of 8.6 or less. According to these results, Chito-PEG-SH might show potential as auxiliary agent in oral drug delivery where its solubility even up to pH 8 is likely beneficial. PMID:24382680

  8. Design of chitosan-based nanoparticles functionalized with gallic acid.

    PubMed

    Lamarra, J; Rivero, S; Pinotti, A

    2016-10-01

    Active nanoparticles based on chitosan could be applied as a support for the modulation of gallic acid delivery. In this sense, these nanostructures could be employed in different fields such as food, packaging, and pharmaceutical areas. The design parameters of chitosan-based nanoparticles functionalized with gallic acid (GA) were optimized through RSM by means of the analysis of zeta potential (ZP) and percentage encapsulation efficiency (PEE). The nanoparticles were prepared by ionotropic gelation using tripolyphosphate (TPP), at different combinations of chitosan (CH) concentration, CH:TPP ratio and GA. Global desirability methodology allowed finding the optimum formulation that included CH 0.76% (w/w), CH:TPP ratio of 5 and 37mgGA/gCH leading to ZP of +50mV and 82% of PEE. Analysis through QuickScan and turbidity demonstrated that the most stable nanoparticle suspensions were achieved combining concentrations of chitosan ranging between 0.5 and 0.75% with CH:TPP ratios higher than 3. These suspensions had high stability confirmed by means ZP and transmittance values which were higher than +25mV and 0.21 on average, respectively, as well as nanoparticle diameters of about 140nm. FTIR revealed the occurrence of both hydrogen bond and ionic interactions of CH-TPP which allowed the encapsulation and the improvement of the stability of the active agent. PMID:27287172

  9. Study on the grafting of chitosan-gelatin microcapsules onto cotton fabrics and its antibacterial effect.

    PubMed

    Liu, Jiayi; Liu, Chaohong; Liu, Yingju; Chen, Minjie; Hu, Yang; Yang, Zhuohong

    2013-09-01

    In this work, patchouli oil embedded chitosan-gelatin microcapsules were prepared by the complex coacervation method. Their surface and morphology were characterized by scanning electron microscopy (SEM), showing that the microcapsules were with a regular spherical shape in the range of 1 and 20 μm. In the thermal stability analysis, the microcapsules were stable below 190°C, which indicated the fabrics finish can be conducted at 160°C. The encapsulation efficiency (EE) and loading capacity (LC) of the microcapsules were calculated as 50.69% and 30.31%, respectively. Then, the microcapsules were grafted onto cotton fabrics using 2D resin (dimethyloldihydroxyethylene urea, DMDHEU) as the crosslinking reagent. SEM showed that the microcapsules were not only grafted on the surface of the fabrics, but also inserted in the spacing of the fibers. In addition, the formation of ether bonds between 2D resin and hydroxyl groups of cotton and/or hydroxyl groups of the microcapsules was identified by Fourier transform infrared spectroscopy (FTIR). Finally, the antibacterial rate of the fabrics for Staphylococcus aureus and Escherichia coli were about 65% even after being washed 25 times, suggesting its potential application in many fields such as antibacterial mask, bacteriostatic sheet and health-care clothes. PMID:23624277

  10. Microwave assisted preparation of n-butylacrylate grafted chitosan and its application for Cr(VI) adsorption.

    PubMed

    Santhana Krishna Kumar, A; Uday Kumar, Chinta; Rajesh, Vidya; Rajesh, N

    2014-05-01

    Biopolymers such as chitosan possess excellent properties suited for varied applications. In this work, we describe a novel microwave assisted method for the preparation of n-butylacrylate grafted chitosan adsorbent and its utility for the adsorption of chromium(VI). A 3 min irradiation time was enough to prepare the adsorbent, and techniques such as FT-IR, powder XRD, SEM and EDS were used for comprehensive characterization. The adsorption was effective at pH 3.5 with 25 mL of 20 ppm Cr(VI) solution. Langmuir, Freundlich, Dubinin-Radushkevich, Temkin, Elovich and Redlich isotherms were studied in detail. The ΔG, ΔH and ΔS parameters were evaluated to understand the adsorption thermodynamics. The adsorption involves the interaction of Cr(VI) with the hydroxyl and amino groups in chitosan. PMID:24530325

  11. Radiation-induced graft copolymerization of poly(ethylene glycol) monomethacrylate onto deoxycholate-chitosan nanoparticles as a drug carrier

    NASA Astrophysics Data System (ADS)

    Pasanphan, Wanvimol; Rattanawongwiboon, Thitirat; Rimdusit, Pakjira; Piroonpan, Thananchai

    2014-01-01

    Poly(ethylene glycol) monomethacrylate-grafted-deoxycholate chitosan nanoparticles (PEGMA-g-DCCSNPs) were successfully prepared by radiation-induced graft copolymerization. The hydrophilic poly(ethylene glycol) monomethacrylate was grafted onto deoxycholate-chitosan in an aqueous system. The radiation-absorbed dose is an important parameter on degree of grafting, shell thickness and particle size of PEGMA-g-DCCSNPs. Owing to their amphiphilic architecture, PEGMA-g-DCCSNPs self-assembled into spherical core-shell nanoparticles in aqueous media. The particle size of PEGMA-g-DCCSNPs measured by TEM varied in the range of 70-130 nm depending on the degree of grafting as well as the irradiation dose. Berberine (BBR) as a model drug was encapsulated into the PEGMA-g-DCCSNPs. Drug release study revealed that the BBR drug was slowly released from PEGMA-g-DCCSNPs at a mostly constant rate of 10-20% in PBS buffer (pH 7.4) at 37 °C over a period of 23 days.

  12. Modeling and optimization of the flocculation processes for removal of cationic and anionic dyes from water by an amphoteric grafting chitosan-based flocculant using response surface methodology.

    PubMed

    Wu, Hu; Yang, Ran; Li, Ruihua; Long, Chao; Yang, Hu; Li, Aimin

    2015-09-01

    In this study, an amphoteric grafting chitosan-based flocculant (carboxymethyl chitosan-graft-poly(2-methacryloyloxyethyl) trimethyl ammonium chloride, denoted as CMC-g-PDMC) was applied to removal of the anionic and cationic dyes, acid Green 25 (AG25) and Basic Bright Yellow (7GL), from water. Flocculation conditions have been optimized by response surface methodology (RSM) on the basis of central composite design (CCD) using flocculant dosage, initial solution pH and temperature as input variables. The second-order and cubic regression models, which have been both tested by the analysis of variance (ANOVA), were constructed to link the output response (the dye removal factor) with the aforementioned input variables, respectively. The second-order regression model well described the process of AG25 removal, whereas the cubic one is more suitable for that of 7GL. The effects of those variables on the flocculation performance of CMC-g-PDMC for removal of the two dyes containing opposite charges from aqueous solutions have been studied, and the flocculation mechanisms including the interactive effects between various influencing factors have been discussed in detail also. PMID:25921759

  13. Selective adsorption of lead on grafted and crosslinked chitosan nanoparticles prepared by using Pb(2+) as template.

    PubMed

    Ge, Huacai; Hua, Tingting; Chen, Xiaodong

    2016-05-01

    Poly(acrylic acid) grafted and glutaraldehyde-crosslinked chitosan nano adsorbent (PAACS) was synthesized by using Pb(2+) as a template ion. The structure and morphology of PAACS were characterized by FT-IR, XRD, SEM and elemental analyses. The adsorption of PAACS for different heavy metal ions was compared and the effects of various variables for adsorption of Pb(2+) were systematically studied. The results indicated that the PAACS was the aggregates of nanoparticles with the diameter of about 50-200 nm and had selectivity for Pb(2+) adsorption. The adsorption for Pb(2+) showed a maximum adsorption capacity of 734.3 mg g(-1) at pH 5.0 and 303 K, which was higher than in a study previously reported on ion-imprinted adsorbents. The adsorption followed the pseudo-second-order kinetics and Langmuir isotherm models. The adsorption was spontaneous and changed from chemical process into physical process when the temperature exceeded 303 K. The adsorbent could be recycled with EDTA. Therefore, PAACS would be useful as a selective and high uptake nano adsorbent in the removal of Pb(2+) from effluents. PMID:26844403

  14. Optical properties of chitosan in aqueous solution of L- and D-ascorbic acids

    NASA Astrophysics Data System (ADS)

    Malinkina, Olga N.; Shipovskaya, Anna B.; Kazmicheva, Olga F.

    2016-04-01

    The optical properties of aqueous chitosan solutions in L- and D-ascorbic acids were studied by optical rotatory dispersion and spectrophotometry. The specific optical rotation [α] of all chitosan solutions tested was positive, in contrast to aqueous solutions of the ascorbic acid enantiomers, which exhibit an inverse relationship of [α] values. Significant differences in the absolute values of [α] of the chitosan solutions at polymer-acid ratios exceeding the equimolar one were found.

  15. Design of Chitosan-Grafted Carbon Nanotubes: Evaluation of How the –OH Functional Group Affects Cs+ Adsorption

    PubMed Central

    Yang, Shubin; Shao, Dadong; Wang, Xiangke; Hou, Guangshun; Nagatsu, Masaaki; Tan, Xiaoli; Ren, Xuemei; Yu, Jitao

    2015-01-01

    In order to explore the effect of –OH functional groups in Cs+ adsorption, we herein used the low temperature plasma-induced grafting method to graft chitosan onto carbon nanotubes (denoted as CTS-g-CNTs), as raw-CNTs have few functional groups and chitosan has a large number of –OH functional groups. The synthesized CTS-g-CNT composites were characterized using different techniques. The effect of –OH functional groups in the Cs+ adsorption process was evaluated by comparison of the adsorption properties of raw-CNTs with and without grafting chitosan. The variation of environmental conditions such as pH and contact time was investigated. A comparison of contaminated seawater and simulated groundwater was also evaluated. The results indicated that: (1) the adsorption of Cs+ ions was strongly dependent on pH and the competitive cations; (2) for CNT-based material, the –OH functional groups have a positive effect on Cs+ removal; (3) simulated contaminated groundwater can be used to model contaminated seawater to evaluate the adsorption property of CNTs-based material. These results showed direct observational evidence on the effect of –OH functional groups for Cs+ adsorption. Our findings are important in providing future directions to design and to choose effective material to remedy the removal of radioactive cesium from contaminated groundwater and seawater, crucial for public health and the human social environment. PMID:26006711

  16. Evaluation of structural and functional properties of chitosan-chlorogenic acid complexes.

    PubMed

    Wei, Zihao; Gao, Yanxiang

    2016-05-01

    The objectives of the present study were to first synthesize chitosan-chlorogenic acid (CA) covalent complex and then compare structural and functional properties between chitosan-CA covalent complex and physical complex. First, chitosan-CA covalent complex was synthesized and its total phenolic content was as high as 276.5 ± 6.2 mg/g. Then structural and functional properties of chitosan-CA covalent and physical complexes were analyzed. The covalent reaction induced formation of both amide and ester bonds in chitosan. Data of X-ray diffraction (XRD) and scanning electron microscopy (SEM) indicated that the complexations of CA changed crystallinity and morphology of chitosan, and covalent complexation induced a larger change of physical structure than physical complexation. In terms of functional properties, chitosan-CA covalent complex exhibited better thermal stability than physical complex in terms of antioxidant activity, and the viscosity of chitosan was significantly increased by covalent modification. PMID:26820353

  17. Effect of phytic acid, ethylenediaminetetraacetic acid, and chitosan solutions on microhardness of the human radicular dentin

    PubMed Central

    Nikhil, Vineeta; Jaiswal, Shikha; Bansal, Parul; Arora, Rohit; Raj, Shalya; Malhotra, Pulkit

    2016-01-01

    Aim: The purpose of this study was to evaluate the effect of phytic acid, ethylenediaminetetraacetic acid (EDTA), and chitosan solutions on the microhardness of human radicular dentin. Materials and Methods: Thirty dentin specimens were randomly divided into three groups of 10 specimens each according to the irrigant used: G1 — 1% phytic acid, G2 — 17% EDTA, and G3 — 0.2% chitosan. A standardized volume of each chelating solution was used for 3 min. Dentin microhardness was measured before and after application at the cervical, middle, and apical levels with a Vickers indenter under a 200-g load and a 10-s dwell time. The results were analyzed using one-way analysis of variance (ANOVA) and Student's t test. Results: Microhardness of the radicular dentin varied at the cervical, middle, and apical levels. EDTA had the greatest overall effect, causing a sharp percentage reduction in dentin microhardness with a significant difference from phytic acid and chitosan (P = 0.002). However, phytic acid and chitosan differed insignificantly from each other (P = 0.887). Conclusion: All tested chelating solutions reduced microhardness of the radicular dentin layer at all the levels. However, reduction was least at the apical level. EDTA caused more reduction in dentin microhardness than chitosan while phytic acid reduced the least. PMID:27099428

  18. Fabrication of cationic nanomicelle from chitosan-graft-polycaprolactone as the carrier of 7-ethyl-10-hydroxy-camptothecin.

    PubMed

    Duan, Kongrong; Zhang, Xiaolan; Tang, Xiaoxing; Yu, Jiahui; Liu, Shiyuan; Wang, Daxin; Li, Yaping; Huang, Jin

    2010-04-01

    In this research, amphiphilic brush-like polycations were synthesized, and used to fabricate cationic nanomicelle as the carrier of 7-ethyl-10-hydroxy-camptothecin (SN-38), in order to enhance its cellular uptake, solubility and stability in aqueous media. In particular, cationic chitosan-graft-polycaprolactone (CS-g-PCL) copolymers were synthesized with a facile one-pot manner via ring-opening polymerization of epsilon-CL onto the hydroxyl groups of CS by using methanesulfonic acid as solvent and catalyst. The formation of CS-g-PCL nanomicelles was confirmed by fluorescence spectrophotoscopy and particle size measurements. It was found that all the nanomicelles showed spherical shapes with narrow size distributions. Their sizes ranged from 47 to 113 nm, and the zeta potentials ranged from 26.7 to 50.8 mV, depending on the grafting content of PCL in CS-g-PCL, suggesting their passive targeting to tumor tissue and endocytosis potential. Water-insoluble antitumor drug, SN-38, was easily encapsulated into CS-g-PCL nanomicelles by lyophilization method. In comparison with bare CS-g-PCL nanomicelles, the corresponding SN-38-loaded nanomicelles showed increased particle sizes and a little reduced zeta potentials. With an increase of grafting PCL content, the drug encapsulation efficiency (EE) and drug loading (DL) of the nanomicelles increased from 64.3 to 84.6% and 6.43 to 8.66%, respectively, whereas their accumulative drug release showed a tendency to decrease due to the enhanced hydrophobic interaction between hydrophobic drug and hydrophobic PCL segments in CS-g-PCL. Also, the CS-g-PCL nanomicelles effectively protected the active lactone ring of SN-38 from hydrolysis under physiological condition, due to the encapsulation of SN-38 into the hydrophobic cores in the nanomicelles. Compared with free SN-38, the SN-38-loaded nanomicelles showed essential decreased cytotoxicity against L929 cell line, and bare CS-g-PCL nanomicelles almost showed non-toxicity. These

  19. Kinetic study of acid depolymerization of chitosan and effects of low molecular weight chitosan on erythrocyte rouleaux formation.

    PubMed

    Tsao, Ching Ting; Chang, Chih Hao; Lin, Yu Yung; Wu, Ming Fung; Han, Jin Lin; Hsieh, Kuo Huang

    2011-01-01

    In this study, the depolymerization of chitosan was carried out in an acetic acid aqueous solution and was followed by viscometry for molecular weight determination. It was found that the depolymerization rate increased with elevated temperatures and with high acid concentrations. Based on FTIR analysis, the chitosan was depolymerized randomly along the backbone; no other structural change was observed during the acid depolymerization process. Revealed in the TGA study, the degradation temperature and char yield of LMWCs (low molecular weight chitosan) were molecular weight dependent. The blood compatibility of LMWCs was also investigated: rouleaux formation was observed when erythrocyte contacted with LMWCs, which showed that LMWCs are able to interfere with the negatively charged cell membrane through its polycationic properties. Furthermore, as regards a kinetics investigation, the values of M(n) (number-average molecular weight) were obtained from an experimentally determined relationship. The kinetics study showed that the complex salt, formed by amine on chitosan and acetic acid, acted as catalyst. Finally, the activation energy for the hydrolysis of the glycosidic linkage on chitosan was calculated to be 40kJ/mol; the mechanism of acid depolymerization is proposed. In summary, LMWCs could be easily and numerously generated with acid depolymerization for further biological applications. PMID:21075360

  20. PK11195-chitosan-graft-polyethylenimine-modified SPION as a mitochondria-targeting gene carrier.

    PubMed

    Kim, You-Kyoung; Zhang, Mei; Lu, Jin-Jian; Xu, Fengguo; Chen, Bao-An; Xing, Lei; Jiang, Hu-Lin

    2016-06-01

    Superparamagnetic iron oxide nanoparticle (SPION) holds great potential as a gene delivery system due to its unique properties, such as good biocompatibility and non-invasive targeting ability. In this study, we modified SPION with chitosan-graft-PEI (CHI-g-PEI) and PK11195, to fabricate a mitochondria-targeting gene carrier, PK-CP-SPION. PK-CP-SPION manifested prominent physicochemical properties for magnetic guided gene delivery, and it could effectively condense and protect DNA at proper weight ratios. The in vitro cytotoxicity of PK-CP-SPIONs was mild. Under an external magnetic field, the transfection efficiency of PK-CP-SPIONs was comparable to PEI 25 K with shorter transfection time. PK11195 facilitated the specific accumulation of PK-CP-SPIONs in mitochondria, leading to the leakage of cytochrome c, the dissipation of mitochondrial membrane potential and subsequently the activation of mitochondria apoptosis pathway. These results indicated that with further development, PK-CP-SPIONs could serve as a multifunctional nanoplatform for magnetic targeting gene delivery and mitochondria-targeting therapy, leading enhanced therapeutic effect towards tumor cells. PMID:26390926

  1. Preparation, Characterization, and Insecticidal Activity of Avermectin-Grafted-Carboxymethyl Chitosan

    PubMed Central

    Li, Yan; Qin, Yukun; Liu, Song; Xing, Ronge; Yu, Huahua; Li, Kecheng; Li, Pengcheng

    2016-01-01

    Avermectin-grafted-N,O-carboxymethyl chitosan (NOCC) derivative was obtained by esterification reaction using dicyclohexylcarbodiimide (DCC) as dehydrating agent and 4-methylaminopyridine as catalyst. The structures of the conjugate were confirmed by FT-IR, 1H NMR, and XRD. Insecticidal activities against armyworms, carmine spider mites, black bean aphids, and brown plant hoppers were investigated at concentrations ranging from 0.16 to 1000 mg/L. At the concentration of 1000 mg/L and 500 mg/L, the lethal rate was 100%. Good insecticidal activity at 4 mg/L was still shown, especially against the black bean aphids and brown plant hoppers. Moreover, the photostability of the conjugate was evaluated and showed an apparent improvement. At 300 mins, the residual rate of the conjugate was 11.22%, much higher than 0.2% of the avermectin technical material. The conjugate we developed showed potential for further study and application in crop protection. PMID:27213156

  2. Preparation of chitosan grafted graphite composite for sensitive detection of dopamine in biological samples.

    PubMed

    Palanisamy, Selvakumar; Thangavelu, Kokulnathan; Chen, Shen-Ming; Gnanaprakasam, P; Velusamy, Vijayalakshmi; Liu, Xiao-Heng

    2016-10-20

    The accurate detection of dopamine (DA) levels in biological samples such as human serum and urine are essential indicators in medical diagnostics. In this work, we describe the preparation of chitosan (CS) biopolymer grafted graphite (GR) composite for the sensitive and lower potential detection of DA in its sub micromolar levels. The composite modified electrode has been used for the detection of DA in biological samples such as human serum and urine. The GR-CS composite modified electrode shows an enhanced oxidation peak current response and low oxidation potential for the detection of DA than that of electrodes modified with bare, GR and CS discretely. Under optimum conditions, the fabricated GR-CS composite modified electrode shows the DPV response of DA in the linear response ranging from 0.03 to 20.06μM. The detection limit and sensitivity of the sensor were estimated as 0.0045μM and 6.06μA μM(-1)cm(-2), respectively. PMID:27474582

  3. The highly effective removal of Cs⁺ by low turbidity chitosan-grafted magnetic bentonite.

    PubMed

    Yang, Shubin; Okada, Naoya; Nagatsu, Masaaki

    2016-01-15

    Chitosan-grafted magnetic bentonite (CS-g-MB) was successfully synthesized via a plasma-induced method. The CS-g-MB composite shows good magnetic properties, low turbidity, and high stability in aqueous solution and exhibits significant adsorption capacity for Cs(+) ions. The adsorption of Cs(+) by CS-g-MB is dependent on both pH and ionic strength. In the presence of Mg(2+), K(+), Li(+), and Na(+) ions, the Cs(+) exchange is constrained in the order of Li(+)≈Mg(2+)

  4. Adsorption of uranium by amidoximated chitosan-grafted polyacrylonitrile, using response surface methodology.

    PubMed

    Xu, Chao; Wang, Jingjing; Yang, Tilong; Chen, Xia; Liu, Xunyue; Ding, Xingcheng

    2015-05-01

    The amidoximated chitosan-grafted polyacrylonitrile (CTS-g-PAO) was prepared for the adsorption of uranium from water. The effects of pH, concentration of uranium and the solid-liquid ratio on the adsorption of uranium by CTS-g-PAO were optimized using Doehlert design of response surface methodology (RSM). The adsorption capacity and removal efficiency achieved 312.06 mg/g and 86.02%, respectively. The adsorption process attained equilibrium only in 120 min. More than 80% of the absorbed uranium could be desorbed by 0.1 mol/l HCl or EDTA-Na, and CTS-g-PAO could be reused at least 3 times. The CTS-g-PAO and U(VI) ions formed a chelate complex due to FTIR spectral analysis. The surface morphology of CTS-g-PAO was also investigated by SEM. The adsorption process was better described by Langmuir isotherm and pseudo second order kinetic model. Results obtained indicated that CTS-g-PAO was very promising in adsorption of uranium from water. PMID:25659674

  5. Preparation, Characterization, and Insecticidal Activity of Avermectin-Grafted-Carboxymethyl Chitosan.

    PubMed

    Li, Yan; Qin, Yukun; Liu, Song; Xing, Ronge; Yu, Huahua; Li, Kecheng; Li, Pengcheng

    2016-01-01

    Avermectin-grafted-N,O-carboxymethyl chitosan (NOCC) derivative was obtained by esterification reaction using dicyclohexylcarbodiimide (DCC) as dehydrating agent and 4-methylaminopyridine as catalyst. The structures of the conjugate were confirmed by FT-IR, (1)H NMR, and XRD. Insecticidal activities against armyworms, carmine spider mites, black bean aphids, and brown plant hoppers were investigated at concentrations ranging from 0.16 to 1000 mg/L. At the concentration of 1000 mg/L and 500 mg/L, the lethal rate was 100%. Good insecticidal activity at 4 mg/L was still shown, especially against the black bean aphids and brown plant hoppers. Moreover, the photostability of the conjugate was evaluated and showed an apparent improvement. At 300 mins, the residual rate of the conjugate was 11.22%, much higher than 0.2% of the avermectin technical material. The conjugate we developed showed potential for further study and application in crop protection. PMID:27213156

  6. Branched polyethylenimine-grafted-carboxymethyl chitosan copolymer enhances the delivery of pDNA or siRNA in vitro and in vivo

    PubMed Central

    Park, Seong-Cheol; Nam, Joung-Pyo; Kim, Young-Min; Kim, Jun-Ho; Nah, Jae-Woon; Jang, Mi-Kyeong

    2013-01-01

    To generate a good carrier for gene transfection, O-carboxymethyl chitosan-graft-branched polyethylenimine (OCMPEI) copolymers were synthesized by increasing the weight percentage of branched polyethylenimine conjugated to the carboxyl groups of O-carboxymethyl chitosan. These spherical polyplexes with plasmid deoxyribonucleic acid (pDNA) or small interfering ribonucleic acid (siRNA) had diameters of ∼200–300 nm or ∼10–25 nm, respectively, and displayed significant transfection efficiency in normal and tumor cells. In particular, expression of green fluorescent protein (GFP) following pDNA transfection was effectively suppressed by delivery of GFP-specific siRNA with the same copolymer. The optimized copolymer and polyplexes were nontoxic in vitro and in vivo. The use of endocytosis inhibitors to investigate the mechanisms of transfection of the polyplexes suggested the involvement of macropinocytosis. An in vivo study in mice showed excellent GFP expression in the lung, kidney, and liver. The results demonstrated that the OCMPEI copolymer prepared in this study is a promising carrier for in vitro and in vivo gene delivery applications. PMID:24106426

  7. Sulfonic acid catalysts prepared by radiation-induced graft polymerization

    SciTech Connect

    Mizota, Tomotoshi; Tsuneda, Satoshi; Saito, Kyoichi, Saito

    1994-09-01

    In this study, the authors prepared two variations of graft-type acid catalysts with different adjacent groups by radiation-induced graft polymerization (RIGP), and compared the hydrolytic activity of the resultant acid catalysts for methyl acetate with that of commercially available SO{sub 3}H-type ion-exchange beads with different degrees of cross-linking. 8 refs., 3 figs.

  8. The removal of kaolinite suspensions by acid-soluble and water-soluble chitosans.

    PubMed

    Chung, Ying-Chien; Wu, Li-Chun; Chen, Chih-Yu

    2013-01-01

    Chitosan is a potential substitute for traditional aluminium salts in water treatment systems. This research compared the coagulant performance of acid-soluble chitosan with water-soluble chitosan and with coagulant mixtures of chitosan and aluminium sulfate (alum). We also assessed the coagulant performance of chitosan and poly-aluminium chloride (PAC) to remove kaolinite from turbid water. In addition, we evaluated their respective coagulation efficiencies under different coagulant concentrations, degrees of turbidity (NTU) and pH levels. Furthermore, we determined the size and settling velocity of flocs formed by these coagulants in order to illustrate major factors affecting kaolinite coagulation. The optimal concentrations of acid- versus water- soluble chitosan required to remove kaolinite from a 300 NTU suspension were 4.0 and 10.0 mg/l, respectively-with individual efficiencies of 79.3 and 92.4%, in that order. Optimum concentrations ofwater-soluble chitosan demonstrated a broader range than that of acid-soluble chitosan. In addition, it is of note that chitosan/alum and chitosan/PAC water-soluble coagulant mixtures demonstrated much wider ranges of optimal concentrations for turbidity reduction than either alum or PAC alone. Moreover, our water-soluble chitosan coagulant mixtures produced denser floc with elevated settling velocities that favour cost savings relevant to both installation and operational expenses. Based on our observations of these noteworthy performances, we confidently propose that a coagulant mixture with a 1:1 mass ratio of chitosan and alum presents a remarkably more cost-effective alternative to the use of chitosan alone in water treatment systems. PMID:23530342

  9. Surface Molecularly Imprinted Polymer of Chitosan Grafted Poly(methyl methacrylate) for 5-Fluorouracil and Controlled Release

    PubMed Central

    Zheng, Xue-Fang; Lian, Qi; Yang, Hua; Wang, Xiuping

    2016-01-01

    The molecular surface imprinted graft copolymer of chitosan with methyl methacrylate (MIP-CS-g-PMMA) were prepared by free radical polymerization with 5-fluorouracil (5-FU) as the template molecule using initiator of ammonium persulfate as adsorption system. MIPs were characterized by FTIR, X-ray diffraction, thermo-gravimetric analysis, 1H NMR and SEM. The mechanism of graft copolymerization and factors affected graft reaction were studied in details, and the optimum reaction conditions (to the highest %G and %E as the standard) were obtained at [MMA] 1.2 mol/L, [Chitosan] 16.67 mol/L, [initiator] 0.0062 mol/L, temperature 60 °C and reaction time 7 h. MIPs exhibited high recognition selectivity and excellent combining affinity to template molecular. The in vitro release of the 5-FU was highly pH-dependent and time delayed. The release behavior showed that the drugs did not release in simulated gastric fluid (pH = 1.0), and the drug release was small in the simulated small intestinal fluid (pH = 6.8), and drug abrupt release will be produced in the simulated colon fluid (pH = 7.4), indicating excellent colon-specific drug delivery behavior. PMID:26892676

  10. Surface Molecularly Imprinted Polymer of Chitosan Grafted Poly(methyl methacrylate) for 5-Fluorouracil and Controlled Release.

    PubMed

    Zheng, Xue-Fang; Lian, Qi; Yang, Hua; Wang, Xiuping

    2016-01-01

    The molecular surface imprinted graft copolymer of chitosan with methyl methacrylate (MIP-CS-g-PMMA) were prepared by free radical polymerization with 5-fluorouracil (5-FU) as the template molecule using initiator of ammonium persulfate as adsorption system. MIPs were characterized by FTIR, X-ray diffraction, thermo-gravimetric analysis, (1)H NMR and SEM. The mechanism of graft copolymerization and factors affected graft reaction were studied in details, and the optimum reaction conditions (to the highest %G and %E as the standard) were obtained at [MMA] 1.2 mol/L, [Chitosan] 16.67 mol/L, [initiator] 0.0062 mol/L, temperature 60 °C and reaction time 7 h. MIPs exhibited high recognition selectivity and excellent combining affinity to template molecular. The in vitro release of the 5-FU was highly pH-dependent and time delayed. The release behavior showed that the drugs did not release in simulated gastric fluid (pH = 1.0), and the drug release was small in the simulated small intestinal fluid (pH = 6.8), and drug abrupt release will be produced in the simulated colon fluid (pH = 7.4), indicating excellent colon-specific drug delivery behavior. PMID:26892676

  11. Radiation grafting studies of acrylic acid onto cellulose triacetate membranes

    NASA Astrophysics Data System (ADS)

    Mazzei, R. O.; Smolko, E.; Torres, A.; Tadey, D.; Rocco, C.; Gizzi, L.; Strangis, S.

    2002-05-01

    Polymer surface modifications were obtained by the application of radiation treatments, etching and grafting of acrylic acid monomers on different membranes of cellulose triacetate materials. Cellulose triacetate foils from pellet dissolution and commercial cellulose triacetate solid state nuclear track detector membranes were assayed. Irradiation with fission fragments from Cf-252 source to obtain a porous structure, 25 MeV proton beam and Co-60 γ-source to produce peroxides were employed in the experiments. The present work gives the grafting yield of AAc monomer onto CTA membranes as a function of diverse variables including irradiation parameters ( γ-dose, Cf-252 ff irradiation time, proton fluency and electronic energy loss (d E/d x) e), structural parameters (pore diameter and pore density, etching time and etching temperature) and grafting parameters (monomer and Mohr salt concentration, grafting time and grafting temperature).

  12. Chitosan

    PubMed Central

    Smith, Alan; Perelman, Michael; Hinchcliffe, Michael

    2014-01-01

    The nasal route is attractive for the delivery of vaccines in that it not only offers an easy to use, non-invasive, needle-free alternative to more conventional parenteral injection, but it also creates an opportunity to elicit both systemic and (crucially) mucosal immune responses which may increase the capability of controlling pathogens at the site of entry. Immune responses to “naked” antigens are often modest and it is widely accepted that incorporation of an adjuvant is a prerequisite for the achievement of clinically effective nasal vaccines. Many existing adjuvants are sub-optimal or unsuitable because of local toxicity or poor enhancement of immunogenicity. Chitosan, particularly chitosan salts, have now been used in several preclinical and clinical studies with good tolerability, excellent immune stimulation and positive clinical results across a number of infections. Particularly significant evidence supporting chitosan as an adjuvant for nasal vaccination comes from clinical investigations on a norovirus vaccine; this demonstrated the ability of chitosan (ChiSys®), when combined with monophosphoryl lipid, to evoke robust immunological responses and confer protective immunity following (enteral) norovirus challenge. This article summarizes the totality of the meaningful information (including key unpublished data) supporting the development of chitosan-adjuvanted vaccines. PMID:24346613

  13. Inactivation of salmonella on tomato stem scars by edible chitosan and organic Acid coatings.

    PubMed

    Jin, T; Gurtler, J B

    2012-08-01

    This study was conducted to investigate the efficacy of antimicrobial coatings for inactivation of Salmonella on the surface of tomato stem scars. Scars were inoculated with a four-strain cocktail of Salmonella (serovars Montevideo, Newport, Saintpaul, and Typhimurium) and coated with acid-chitosan solutions. The chitosan coating with three acids (3A plus chitosan), the chitosan coating with one acid, and the three-acid solution without chitosan reduced the populations of Salmonella by 6.0, 3.6, and 5.3 log CFU per stem scar, respectively. Addition of allyl isothiocyanate (10 μl/ml) to the 3A plus chitosan coating did not significantly increase (P > 0.05) the antimicrobial efficacy. Although the populations of Salmonella in the controls (ca. 7.5 log CFU per stem scar) did not change significantly throughout the 14-day storage period at 10° C, Salmonella cells were reduced to undetectable levels (< 0.7 log CFU per stem scar) in the samples treated with 3A plus chitosan coating after two days of storage, and no growth was observed for the remaining storage period. Results from this study demonstrate that coatings of acid plus chitosan provide an alternative antimicrobial intervention for decontamination of tomatoes. PMID:22856559

  14. Effect of Chitosan Dissolved in Different Acids on its Ability to Control Postharvest Gray Mold of Table Grape

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chitosan is a natural biopolymer that must be dissolved in an acid solution to activate its antimicrobial and eliciting properties. Among 15 acids, chitosan dissolved in 1% solutions of acetic, L-ascorbic, formic, L-glutamic, hydrochloric, lactic, maleic, malic, phosphorous, and succinic. Chitosan s...

  15. Enhanced intracellular uptake and endocytic pathway selection mediated by hemocompatible ornithine grafted chitosan polycation for gene delivery.

    PubMed

    Alex, Susan M; Sharma, Chandra P

    2014-10-01

    Nanotechnology is adopted in gene therapy research to create gene vectors that will facilitate gene transfer to cells with utmost efficacy and safety. For vector design, polymers are the preferred nonviral colloidal systems as they are feasible for any chemical modifications. In this study, chitosan, a versatile biopolymer has been subjected to chemical conjugation with the amino acid ornithine to generate chitosan-ornithine conjugate (CON) for gene delivery. With the help of FTIR and (1)H NMR spectra the chemical composition of the chitosan derivative was confirmed. Buffering capacity was found enhanced with the synthesised chitosan derivative when compared to the parent unmodified chitosan. The cationic derivative formed nanoparticles when mixed with negatively charged DNA. The nanoparticles showed good DNA retardation ability in agarose gel electrophoresis and sizes were ascertained by DLS and TEM observations. The derivative on interaction with blood plasma showed negligible protein adsorption and did not cause either hemolysis or RBC aggregation in blood. In vitro cell culture also revealed the CON derivative to be nontoxic to cells and capable of transfection with an explicit increase in cellular uptake of nanoparticles. An uptake study in the presence of endocytosis inhibitors indicated the specific pathway used for cell entry. The results revealed that the clathrin mediated pathway and dynamin played a role in the internalisation of these specific nanoparticles. PMID:25193152

  16. Temperature Shifts for Extraction and Purification of Zygomycetes Chitosan with Dilute Sulfuric Acid

    PubMed Central

    Zamani, Akram; Edebo, Lars; Niklasson, Claes; Taherzadeh, Mohammad J.

    2010-01-01

    The temperature-dependent hydrolysis and solubility of chitosan in sulfuric acid solutions offer the possibility for chitosan extraction from zygomycetes mycelia and separation from other cellular ingredients with high purity and high recovery. In this study, Rhizomucor pusillus biomass was initially extracted with 0.5 M NaOH at 120 °C for 20 min, leaving an alkali insoluble material (AIM) rich in chitosan. Then, the AIM was subjected to two steps treatment with 72 mM sulfuric acid at (i) room temperature for 10 min followed by (ii) 120 °C for 45 min. During the first step, phosphate of the AIM was released into the acid solution and separated from the chitosan-rich residue by centrifugation. In the second step, the residual AIM was re-suspended in fresh 72 mM sulfuric acid, heated at 120 °C and hot filtered, whereby chitosan was extracted and separated from the hot alkali and acid insoluble material (HAAIM). The chitosan was recovered from the acid solution by precipitation at lowered temperature and raised pH to 8–10. The treatment resulted in 0.34 g chitosan and 0.16 g HAAIM from each gram AIM. At the start, the AIM contained at least 17% phosphate, whereas after the purification, the corresponding phosphate content of the obtained chitosan was just 1%. The purity of this chitosan was higher than 83%. The AIM subjected directly to the treatment with hot sulfuric acid (at 120 °C for 45 min) resulted in a chitosan with a phosphate impurity of 18.5%. PMID:21152285

  17. Packaging performance of organic acid incorporated chitosan films on dried anchovy (Stolephorus indicus).

    PubMed

    Vimaladevi, S; Panda, Satyen Kumar; Xavier, K A Martin; Bindu, J

    2015-01-01

    Antimicrobial chitosan films were prepared with acetic acid and propionic acid with glycerol as plasticizer and its efficiency was compared with polyester-polyethylene laminate (PEST/LDPE). The tensile strength of acetic acid/chitosan (ACS) films were higher than propionic acid/chitosan (PCS) films. The elongation percentage (6.43-11.3) and water vapour permeability (0.015-0.03 g/m(2)/day) were significantly lower (p<0.05) for chitosan films when compared to control. Oxygen transmission rate (OTR) of control and propionic acid/chitosan (PCS) films were significantly higher (p<0.05) than acetic acid/chitosan (ACS) films. Dried anchovy (Stolephorus indicus) wrapped in these films were stored at ambient temperature for three months. Quality indices like peroxide value (PV), thiobarbituric acid value (TBA) and microbiological parameters such as aerobic plate count (APC) and total fungal count (TFC) were periodically determined. In terms of microbial and chemical indices, anchovies wrapped in ACS and PCS films were superior to those wrapped with PEST/LDPE films during storage. Study revealed the suitability of chitosan film as wraps for increasing storage stability of dried fish. PMID:25965473

  18. Synthesis and characterization of N-vinylcaprolactam/N,N-dimethylacrylamide grafted onto chitosan networks by gamma radiation

    NASA Astrophysics Data System (ADS)

    Pérez-Calixto, M. P.; Ortega, A.; Garcia-Uriostegui, L.; Burillo, G.

    2016-02-01

    N-vinylcaprolactam (NVCL) and N,N-dimethylacrylamide (DMAAm) were grafted onto crosslinked chitosan by gamma radiation, using direct and indirect (pre-irradiation oxidative) methods. The binary graft systems were synthesized in one and two steps to evaluate the influences of architecture on the properties of the polymeric material. Maximum grafting percentages were obtained by the direct method. The different systems obtained were characterized by FTIR and TGA. The equilibrium swelling time of the (net-CS)-g-NVCL/DMAAm and [(net-CS)-g-NVCL]-g-DMAAm systems was 75 and 25 min, respectively, while crosslinked CS required about 24 h. Thermal and pH sensitivity were conserved in all systems; the pH response in [(net-CS)-g-NVCL]-g-DMAAm (LCST: 37°, pH: 5.2) is more defined than (net-CS)-g-NVCL/DMAAm (LCST: 37 °C, pH: 3.8). Grafting radiation showed to be an effective technique to modify CS hydrogels.

  19. Postharvest chitosan-g-salicylic acid application alleviates chilling injury and preserves cucumber fruit quality during cold storage.

    PubMed

    Zhang, Youzuo; Zhang, Meiling; Yang, Huqing

    2015-05-01

    The effect of salicylic acid with and without chitosan, or a chitosan-g-salicylic acid complex, on chilling injury and post-harvest quality of cucumber stored at 2 °C for 12 days plus 2 days at 20 °C was investigated. The results showed the chitosan-g-salicylic acid coating inhibited chilling injury better than salicylic acid alone or with chitosan. Chitosan-g-salicylic acid also reduced weight loss and respiration rate, limited increases in malondialdehyde content and electrolyte leakage, and maintained higher total soluble solids, chlorophyll and ascorbic acid content. Furthermore, this coating increased the endogenous salicylic acid concentrations and antioxidant enzyme activities including superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase in cucumber during storage. Our study suggests that chitosan-g-salicylic acid alleviated chilling injury in cucumber through sustained-release of salicylic acid and the higher antioxidant enzymes concentrations. PMID:25529719

  20. Efficient sorption of Cu(2+) by composite chelating sorbents based on potato starch-graft-polyamidoxime embedded in chitosan beads.

    PubMed

    Dragan, Ecaterina Stela; Apopei Loghin, Diana Felicia; Cocarta, Ana Irina

    2014-10-01

    Ionic composites based on cross-linked chitosan (CS) as matrix and poly(amidoxime) grafted on potato starch (AOX) as entrapped chelating resin were prepared as beads, for the first time in this work, by two strategies: (1) thorough mixing of previously prepared AOX in the CS solution followed by the bead formation and (2) thorough mixing of the potato starch-g-poly(acrylonitrile) (PS-g-PAN) copolymer in the initial CS solution, followed by bead formation, the amidoximation of the nitrile groups taking place inside the beads. Ionotropic gelation in tripolyphosphate was used to obtain the composite beads, and in situ covalent cross-linking by epichlorohydrin was carried out to stabilize the beads in the acidic pH range. Fourier transform infrared spectroscopy and the swelling ratio values in the acidic pH range confirmed the influence of the synthesis strategy on the structure of the CS/AOX composites. Scanning electron microscopy was employed to reveal the morphology of the novel composites, both before and after their loading with Cu(2+). The binding capacity of Cu(2+) ions as a function of sorbent composition, synthesis strategy, pH, sorbent dose, contact time, initial concentration of Cu(2+), and temperature was examined in batch mode. The main difference between the composites prepared with the two strategies consisted of the higher sorption capacity and the much faster settlement of the equilibrium sorption for the composite prepared by the in situ amidoximation of PS-g-PAN. The Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, and Sips isotherms were applied to fit the sorption equilibrium data. The maximum equilibrium sorption capacity, qm, evaluated by the Langmuir model at 25 °C was 133.15 mg Cu(2+)/g for the CS/AOX composite beads prepared with the first strategy and 238.14 mg Cu(2+)/g for the CS/AOX composite beads prepared with the second strategy, at the same AOX content. The pseudo-second order kinetic model well fitted the sorption kinetics data

  1. Effects of heat treatment on chitosan nanocomposite film reinforced with nanocrystalline cellulose and tannic acid.

    PubMed

    Rubentheren, V; Ward, Thomas A; Chee, Ching Yern; Nair, Praveena; Salami, Erfan; Fearday, Christopher

    2016-04-20

    This article presents an analysis of the influence of heat treatment on chitosan nanocomposite film. A series of samples comprising: pure chitosan film, chitosan film embedded with nanocrystalline cellulose (NCC), chitosan film crosslinked with tannic acid and chitosan film with a blend of NCC and tannic acid were heat treated using a convection oven. Fourier-transform-infrared spectroscopy (FTIR) and X-ray diffraction test (XRD) shows the changes in chemical interaction of the heat treated films. The heat treated films show significant improvements in moisture absorption. Tensile strength and Young's Modulus were increased up to 7MPa and 259MPa, respectively when the samples were subjected to heat treatment. For the NCC particles, a transmission electron microscope (TEM) was used to inspect the structural properties of cellulose particle in suspension form. PMID:26876845

  2. Simultaneous removal of acid green 25 and mercury ions from aqueous solutions using glutamine modified chitosan magnetic composite microspheres.

    PubMed

    Tao, Xue; Li, Kun; Yan, Han; Yang, Hu; Li, Aimin

    2016-02-01

    In this current work, the magnetic composite microsphere containing glutamine modified chitosan and silica coated Fe3O4 nanoparticles (CS-Gln-MCM) has been successfully prepared and extensively characterized, which is a kind of biodegradable materials. CS-Gln-MCM shows enhanced removal efficiency for both acid green 25 (AG25), an amphoteric dye, and mercury ions (Hg(2+)) from water in the respective while measured pH range compared with chitosan magnetic composite microsphere (CS-MCM) without modification. It is due to the fact that the grafted amino acid provides a variety of additional adsorption active sites and diverse adsorption mechanisms are involved. In AG25 and Hg(2+) aqueous mixture, the modified adsorbents bear preferential adsorption for AG25 over Hg(2+) in strong acidic solutions ascribed to multiple interactions between AG25 and CS-Gln-MCM, such as hydrogen bonding and electrostatic interactions. While, in weak acidic conditions, an efficient simultaneous removal is observed for different adsorption effects involved in aforementioned two pollutants. Besides, CS-Gln-MCM illuminates not only short equilibrium time for adsorption of each pollutant less than 20.0 min but also rapid magnetic separation from water and efficient regeneration after saturated adsorption. Therefore, CS-Gln-MCM bears great application potentials in water treatment. PMID:26618263

  3. Proton play in the formation of low molecular weight chitosan (LWCS) by hydrolyzing chitosan with a carbon based solid acid.

    PubMed

    Krishnan, R Akhil; Deshmukh, Pranjal; Agarwal, Siddharth; Purohit, Poorvi; Dhoble, Deepa; Waske, Prashant; Khandekar, Dileep; Jain, Ratnesh; Dandekar, Prajakta

    2016-10-20

    Low molecular weight chitosan (LWCS) constitute a special class of value added chemicals that are primarily obtained from crustacean shells, which are the main water pollutants from crabs and shrimp processing centers. Unlike chitin and chitosan, LWCS possess improved solubility in water and aqueous solutions, making them widely applicable in numerous fields ranging from drug delivery to waste water treatment. Among the methods employed for their production, chemical breakdown by strong liquid acids has yielded good success. However, this method is met with severe concerns arising from the harsh nature of liquid acids, which may corrode the reactors for commercial synthesis, and their limited reusability. The physical methods like ultrasound and microwave are energy intensive in nature, while the enzymatic methods are expensive and offers limited scope for reuse. We have attempted to overcome these problems by employing carbon based solid acid (CSA) for hydrolyzing chitosan to LWCS. CSA can be easily produced using activated carbon, a cost-effective and easily available raw material. Reactions were carried out between chitosan and CSA in a hydrothermal glass reactor and the products, separated by cold centrifugation, were purified and dried. The dried products were characterized for their molecular weight and solubility. Results indicated more than ten-fold decrease in the molecular weight of chitosan and the product exhibited water solubility. The CSA could be used upto four times, without regeneration, to give a consistent quality product. The aqueous solution of resulting LWCS exhibited a pH of 6.03±0.11, as against the acidic pH range of solutions of commercially available LWCS, indicating its suitability for biomedical applications. Our investigation facilitates a 'green approach' that may be employed for commercial production of value added chemicals from waste products of marine industry. PMID:27474584

  4. The contribution of acidulant to the antibacterial activity of acid soluble α- and β-chitosan solutions and their films.

    PubMed

    Jung, Jooyeoun; Cavender, George; Zhao, Yanyun

    2014-01-01

    This study evaluated individual contributions of dissolving acids (acetic acid, lactic acid, and hydrochloric acid) or acid solubilized chitosan to the antibacterial activity against Listeria innocua and Escherichia coli as solutions and dried films. Solutions containing chitosan showed significantly (P < 0.05) different inhibitory activity (measured as percentage of inhibition (PI), in percent) against L. innocua and E. coli, compared to equivalent acid solutions. This increase was calculated as additional inhibition (AI, in percent), which could be as high as 65% in solutions containing 300-320 kDa chitosan depending on the acid type, bacterial species, and the chitosan form (α or β). Solutions containing 4-5 kDa chitosan had lower AI and showed much greater variability among the different chitosan forms, acid types, and bacterial species. Higher molecular weight (Mw) chitosan also showed significantly higher levels of adsorption to bacterial cells than that of lower Mw samples, suggesting that the observed increase in inhibition was the result of surface phenomena. The contribution of acids to the antibacterial activity of chitosan films was assessed by comparing non-rinsed and rinsed films (rinsed in the appropriate broth to remove residual acids and active fragments formed on the dried film). Rinsing β-chitosan films has reduced PI by as much as 28% compared with non-rinsed films, indicating that part of the antibacterial activity of chitosan films is due to the presence of soluble acid compounds and/or other active fragments. Overall, both acidulant and chitosan were found to contribute to the antibacterial activity of acid solubilized α- and β-chitosan, with the exact antibacterial activity of chitosan varying based on the solution and film properties, suggesting a complex interaction. PMID:24196584

  5. A functional chitosan membrane with grafted epigallocatechin-3-gallate and lovastatin enhances periodontal tissue regeneration in dogs.

    PubMed

    Lee, Bor-Shiunn; Lee, Chien-Chen; Lin, Hung-Pin; Shih, Wei-An; Hsieh, Wan-Ling; Lai, Chern-Hsiung; Takeuchi, Yasuo; Chen, Yi-Wen

    2016-10-20

    Currently used guided tissue regeneration (GTR) membranes are mainly used as a barrier to prevent epithelial cells growth into defects before new bone formation. The aim of this study was to develop a tri-layer functional chitosan (CS) membrane with epigallocatechin-3-gallate (EGCG) grafted on the outer layer for bactericidal activity, and lovastatin was included in the middle layer for controlled release. Successful EGCG grafting was demonstrated using Fourier transform infrared spectroscopy and EGCG grafting significantly enhanced adhesion and proliferation of human gingival fibroblasts. The release duration of lovastatin reached 21days. CS-Lovastatin1 produced the highest alkaline phosphatase activity and EGCG14-CS exhibited the best bactericidal activity against periodontopathic bacteria. Finally, the EGCG14-CS-Lovastatin1 membrane showed a higher percentage of bone regeneration than BioMend(®) and control groups in one-walled defects of beagle dogs. These results suggest that the EGCG14-CS-Lovastatin1 membrane has the potential to be used as a novel GTR membrane. PMID:27474626

  6. Eco-friendly Rot and Crease Resistance Finishing of Jute Fabric using Citric Acid and Chitosan

    NASA Astrophysics Data System (ADS)

    Samanta, A. K.; Bagchi, A.

    2013-03-01

    Citric acid (CA) along with chitosan was used on bleached jute fabrics to impart anti crease and rot resistance properties in one step. The treatment was carried out by pad-dry-cure method in presence of sodium hypophosphite monohydrate catalyst. Curing at 150° Centigrade for 5 min delivered good crease resistant property (dry crease recovery angle is 244°) and high rot resistance simultaneously by a single treatment, which are durable for five washings with distilled water. Strength retention of jute fabric after 21 days soil burial was found to be 81 % and the loss (%) in strength due to this treatment was 15-18 %. The results showed that chitosan and CA treated-fabric exhibited higher rot resistance (as indicated by soil burial test) when compared to either CA or chitosan by individual treatment. The effect of CA and chitosan combination on the resistance to rotting of jute fabric was found to be synergistic which is higher than the sum of the effects of individual chemicals. CA possibly reacts with hydroxyl groups in cellulose or chitosan to form ester. The CA and chitosan finished fabric has adverse effect on stiffness. Thermal studies showed that final residue left at 500° C was much higher for CA and chitosan treated fabric than untreated jute fabric. FTIR spectroscopy suggested the formation of ester cross-linkage between the jute fibre, CA and chitosan and hence it is understood that this rot resistant finish on jute fabric become durable by this mechanism.

  7. Silicone hydrogels grafted with natural amino acids for ophthalmological application.

    PubMed

    Xu, Chen; He, Ruiyu; Xie, Binbin; Ismail, Muhammad; Yao, Chen; Luan, Jie; Li, Xinsong

    2016-09-01

    In this report, protein repelling silicone hydrogels with improved hydrophilicity were prepared by photo-polymerization of silicone-containing monomer and glycidyl methacrylate followed by grafting zwitterionic amino acids. The grafted silicone hydrogels possessed excellent hydrophilic surfaces due to the enrichment of amino acids, which was confirmed by attenuated total reflectance Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, contact angle, and equilibrium water content measurements. Remarkable resistance to bovine serum albumin and lysozyme fouling was observed for the silicone hydrogels immobilized with neutrally charged amino acids because of the formation of zwitterionic surfaces with pairs of protonated secondary ammonium cations and deprotonated carboxyl anions. Meanwhile, the silicone hydrogels grafted with positively or negatively charged amino acids were able to repulse same charged protein with reduced deposition and attract oppositely charged protein with increased adsorption. Preliminary cytotoxicity test indicated that the zwitterionic silicone hydrogels were non-cytotoxic. Similarly, three types of natural amino acids, including serine, aspartic acid and histidine, modified silicone hydrogel contact lenses exhibited excellent hydrophilicity and non-damage to the rabbit's eyes, but only serine modified zwitterionic contact lens showed superior protein fouling resistance compared with the current commercial hydrogel contact lens, which may have great potential application in ophthalmology. PMID:27297564

  8. Separation and extraction of Co(II) using magnetic chitosan nanoparticles grafted with β-cyclodextrin and determination by FAAS

    NASA Astrophysics Data System (ADS)

    Moghimi, Ali

    2014-12-01

    A novel and selective method for the fast determination of trace amounts of Co(II) ions in water samples has been developed. The procedure is based on the selective sorption of Co(II) ions using magnetic chitosan nanoparticles grafted with β-cyclodextrin at different pH followed by elution with organic eluents and determination by atomic absorption spectrometry The preconcentration factor was 100 (1 mL elution volume) for a 100 mL sample volume. The limit of detection of the proposed method is 1.0 ng mL-1. The maximum sorption capacity of sorbent under optimum conditions has been found to be 5 mg of Co per gram of sorbent. The relative standard deviation under optimum conditions was 3.0% ( n = 10). Accuracy and applicability of the method was estimated using test samples of natural and model water with different amounts of Co(II).

  9. Synthesis, characterisation and preliminary investigation of the haemocompatibility of polyethyleneimine-grafted carboxymethyl chitosan for gene delivery.

    PubMed

    Liu, Xuan; Mo, Yunfei; Liu, Xiaoyu; Guo, Rui; Zhang, Yi; Xue, Wei; Zhang, Yuanming; Wang, Changyong; Ramakrishna, Seeram

    2016-05-01

    The development of safe and efficient gene carriers is the key to the clinical success of gene therapy. In the present study, carboxymethyl chitosan (CMCS) was prepared by chitosan (CS) alkalisation and carboxymethylation reactions. Then polyethyleneimine (PEI) was grafted to the backbone of CMCS by an amidation reaction. The CMCS-PEI copolymer showed strong complexation capability with DNA to form nanoparticles, and achieved lower cytotoxicity and higher transfection efficiency compared with PEI (25 kDa) towards 293T and 3T3 cells. Moreover, the haemocompatibility of the CMCS-PEI copolymer was investigated through the aggregation, morphology and lysis of human red blood cells (RBCs), along with the impact on the clotting function with activated partial thromboplastin time (APTT), prothrombin time (PT) and thromboelastographic (TEG) assays. The results demonstrated that the CMCS-PEI copolymer with a concentration lower than 0.05 mg/mL had little impact on the aggregation, morphology or lysis of RBCs, or on blood coagulation. Therefore, the copolymer may be a strong alternative candidate as an effective and safe non-viral vector. PMID:26952412

  10. Preparation, property of the complex of carboxymethyl chitosan grafted copolymer with iodine and application of it in cervical antibacterial biomembrane.

    PubMed

    Chen, Yu; Yang, Yumin; Liao, Qingping; Yang, Wei; Ma, Wanfeng; Zhao, Jian; Zheng, Xionggao; Yang, Yang; Chen, Rui

    2016-10-01

    Cervical erosion is one of the common diseases of women. The loop electrosurgical excisional procedure (LEEP) has been used widely in the treatment of the cervical diseases. However, there are no effective wound dressings for the postoperative care to protect the wound area from further infection, leading to increased secretion and longer healing time. Iodine is a widely used inorganic antibacterial agent with many advantages. However, the carrier for stable iodine complex antibacterial agents is lack. In the present study, a novel iodine carrier, Carboxymethyl chitosan-g-(poly(sodium acrylate)-co-polyvinylpyrrolidone) (CMCTS-g-(PAANa-co-PVP), was prepared by graft copolymerization of sodium acrylate (AANa) and N-vinylpyrrolidone (NVP) to a carboxymethyl chitosan (CMCTS) skeleton. The obtained structure could combine prominent property of poly(sodium acrylate) (PAANa) anionic polyelectrolyte segment and good complex property of polyvinylpyrrolidone (PVP) segment to iodine. The bioactivity of CMCTS could also be kept. The properties of the complex, CMCTS-g-(PAANa-co-PVP)-I2, were studied. The in vitro experiment shows that it has broad-spectrum bactericidal effects to virus, fungus, gram-positive bacteria and gram-negative bacteria. A CMCTS-g-(PAANa-co-PVP)-I2 complex contained cervical antibacterial biomembrane (CABM) was prepared. The iodine release from the CABM is pH-dependent. The clinic trial results indicate that CABM has better treatment effectiveness than the conventional treatment in the postoperative care of the LEEP operation. PMID:27287120

  11. Preparation of chitosan-graft-polyacrylamide magnetic composite microspheres for enhanced selective removal of mercury ions from water.

    PubMed

    Li, Kun; Wang, Yawen; Huang, Mu; Yan, Han; Yang, Hu; Xiao, Shoujun; Li, Aimin

    2015-10-01

    A novel magnetic composite microsphere based on polyacrylamide (PAM)-grafted chitosan and silica-coated Fe3O4 nanoparticles (CS-PAM-MCM) was successfully synthesized by a simple method. The molecular structure, surface morphology, and magnetic characteristics of the composite microsphere were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), vibrating-sample magnetometer (VSM), and scanning electron microscopy (SEM). The prepared CS-PAM-MCM was applied as an efficient adsorbent for the removal of copper(II), lead(II), and mercury(II) ions from aqueous solutions in respective single, binary, and ternary metal systems. Compared with chitosan magnetic composite microsphere (CS-MCM) without modification, CS-PAM-MCM showed improved adsorption capacity for each metal ion and highly selective adsorption for Hg from Pb and Cu. This improvement is attributed to the formation of stronger interactions between Hg and the amide groups of PAM branches for chelating effects. The adsorption isotherms of Hg/Cu and Hg/Pb binary metal systems onto CS-PAM-MCM are both well-described by extended and modified Langmuir models, indicating that the removal of the three aforementioned metal ions may follow a similar adsorption manner; that is, through a homogeneous monolayer chemisorption process. Furthermore, these magnetic adsorbents could be easily regenerated in EDTA aqueous solution and reused virtually without any adsorption capacity loss. PMID:26073848

  12. Suppression of the tert-butylhydroquinone toxicity by its grafting onto chitosan and further cross-linking to agavin toward a novel antioxidant and prebiotic material.

    PubMed

    Hernández-Valdepeña, Miguel A; Pedraza-Chaverri, José; Gracia-Mora, Isabel; Hernández-Castro, Rigoberto; Sánchez-Bartez, Francisco; Nieto-Sotelo, Jorge; Montiel, Carmina; Shirai, Keiko; Gimeno, Miquel

    2016-05-15

    The enzyme-mediated grafting of tert-butylhydroquinone (TBHQ) onto chitosan and further crosslinking to agave inulin (agavin) has been successfully achieved in a mild and non-toxic two-step route. The resulting products were characterized by nuclear magnetic resonance (NMR) and Infra-red spectroscopies to assess the molecular structure. The study of acute oral toxicity in mice revealed no adverse short-term effects of consumption in the synthesized materials with non-toxicity evidence until 2000 mg/kg through an oral acute administration. Importantly, this study proves that the compound maintains the radical scavenging capacity of the phenolic antioxidant upon ferric-reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) assays with a measured half-maximal inhibitory concentration (IC50) for the best case of 1.54 g/L based on inhibition of 2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid diammonium salt (ABTS). Additionally, the novel compound presented high prebiotic activities as ascertained in the presence of lactic acid bacteria (LAB). PMID:26775999

  13. Fabrication of a tunable glucose biosensor based on zinc oxide/chitosan-graft-poly(vinyl alcohol) core-shell nanocomposite.

    PubMed

    Shukla, S K; Deshpande, Swapneel R; Shukla, Sudheesh K; Tiwari, Ashutosh

    2012-09-15

    A potentiometrically tuned-glucose biosensor was fabricated using core-shell nanocomposite based on zinc oxide encapsulated chitosan-graft-poly(vinyl alcohol) (ZnO/CHIT-g-PVAL). In a typical experiment, ZnO/CHIT-g-PVAL core-shell nanocomposite containing <20 nm ZnO nanoparticles was synthesized using wet-chemical method. The glucose responsive bio-electrode, i.e., glucose oxidase/ZnO/chitosan-graft-poly(vinyl alcohol) (GOD/ZnO/CHIT-g-PVAL/ITO) was obtained by immobilization of glucose oxidase (GOD) onto the electrode made of resulting ZnO core-shell nanocomposite coated on the indium-tin oxide (ITO) glass substrate. The ZnO/CHIT-g-PVAL/ITO and GOD/ZnO/CHIT-g-PVAL electrodes were characterized with Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), whereas ZnO/CHIT-g-PVAL size of core-shell nanoparticles were measured using transmission electron microscopy (TEM). The electrostatic interaction between GOD and ZnO/CHIT-g-PVAL provided the resulting tuned enzyme electrode with a high degree of enzyme immobilization and excellent lifetime stability. The response studies were carried out as a function of glucose concentration with potentiometric measurement. The GOD/ZnO/CHIT-g-PVAL/ITO bioelectrode has showed a linear potential response to the glucose concentration ranging from 2 μM to 1.2mM. The glucose biosensor exhibited a fast surface-controlled redox biochemistry with a detection limit of 0.2 μM, a sensitivity of >0.04 V/μM and a response time of three sec. ZnO/CHIT-g-PVAL core-shell nanocomposite could be a promising nanomaterials for a range of enzymic biosensors. PMID:22967553

  14. Radiation grafting on natural films

    NASA Astrophysics Data System (ADS)

    Lacroix, M.; Khan, R.; Senna, M.; Sharmin, N.; Salmieri, S.; Safrany, A.

    2014-01-01

    Different methods of polymer grafting using gamma irradiation are reported in the present study for the preparation of newly functionalized biodegradable films, and some important properties related to their mechanical and barrier properties are described. Biodegradable films composed of zein and poly(vinyl alcohol) (PVA) were gamma-irradiated in presence of different ratios of acrylic acid (AAc) monomer for compatibilization purpose. Resulting grafted films (zein/PVA-g-AAc) had their puncture strength (PS=37-40 N mm-1) and puncture deformation (PD=6.5-9.8 mm) improved for 30% and 50% PVA in blend, with 5% AAc under 20 kGy. Methylcellulose (MC)-based films were irradiated in the presence of 2-hydroxyethyl methacrylate (HEMA) or silane, in order to determine the effect of monomer grafting on the mechanical properties of films. It was found that grafted films (MC-g-HEMA and MC-g-silane) using 35% monomer performed higher mechanical properties with PS values of 282-296 N mm-1 and PD of 5.0-5.5 mm under 10 kGy. Compatibilized polycaprolactone (PCL)/chitosan composites were developed via grafting silane in chitosan films. Resulting trilayer grafted composite film (PCL/chitosan-g-silane/PCL) presented superior tensile strength (TS=22 MPa) via possible improvement of interfacial adhesion (PCL/chitosan) when using 25% silane under 10 kGy. Finally, MC-based films containing crystalline nanocellulose (CNC) as a filling agent were prepared and irradiated in presence of trimethylolpropane trimethacrylate (TMPTMA) as a grafted plasticizer. Grafted films (MC-g-TMPTMA) presented superior mechanical properties with a TS of 47.9 MPa and a tensile modulus (TM) of 1792 MPa, possibly due to high yield formation of radicals to promote TMPTMA grafting during irradiation. The addition of CNC led to an additional improvement of the barrier properties, with a significant 25% reduction of water vapor permeability (WVP) of grafted films.

  15. Radiation-induced grafting of acrylic acid onto polypropylene film and its biodegradability

    NASA Astrophysics Data System (ADS)

    Mandal, Dev K.; Bhunia, Haripada; Bajpai, Pramod K.; Chaudhari, C. V.; Dubey, K. A.; Varshney, L.

    2016-06-01

    Polypropylene based commodity polyolefins are widely used in packaging, manufacturing, electrical, pharmaceutical and other applications. The aim of the present work is to study the effect of grafting of acrylic acid on the biodegradability of acrylic acid grafted polypropylene. The effect of different conditions showed that grafting percentage increased with increase in monomer concentration, radiation dose and inhibitor concentration but decreased with increase in radiation dose rate. The maximum grafting of 159.4% could be achieved at optimum conditions. The structure of grafted polypropylene films at different degree of grafting was characterized by EDS, FTIR, TGA, DSC, SEM and XRD. EDS studies showed that the increase in acrylic acid grafting percentage increased the hydrophilicity of the grafted films. FTIR studies indicated the presence of acrylic acid on the surface of polypropylene film. TGA studies revealed that thermal stability decreased with increase in grafting percentage. DSC studies showed that melting temperature and crystallinity of the grafted polypropylene films lower than polypropylene film. SEM studies indicated that increase in acrylic acid grafting percentage increased the wrinkles in the grafted films. The maximum biodegradability could be achieved to 6.85% for 90.5% grafting. This suggested that microorganisms present in the compost could biodegrade acrylic acid grafted polypropylene.

  16. Preparation of Novel Poly(hydroxyethyl methacrylate-coglycidyl methacrylate)-Grafted Core-Shell Magnetic Chitosan Microspheres and Immobilization of Lactase

    PubMed Central

    Zhao, Wei; Yang, Rui-Jin; Qian, Ting-Ting; Hua, Xiao; Zhang, Wen-Bin; Katiyo, Wendy

    2013-01-01

    Poly(hydroxyethyl methacrylate-co-glycidyl methacrylate)-grafted magnetic chitosan microspheres (HG-MCM) were prepared using reversed-phase suspension polymerization method. The HG-MCM presented a core-shell structure and regular spherical shape with poly(hydroxyethyl methacrylate-co-glycidyl methacrylate) grafted onto the chitosan layer coating the Fe3O4 cores. The average diameter of the magnetic microspheres was 10.67 μm, within a narrow size distribution of 6.6–17.4 μm. The saturation magnetization and retentivity of the magnetic microspheres were 7.0033 emu/g and 0.6273 emu/g, respectively. The application of HG-MCM in immobilization of lactase showed that the immobilized enzyme presented higher storage, pH and thermal stability compared to the free enzyme. This indicates that HG-MCM have potential applications in bio-macromolecule immobilization. PMID:23743822

  17. Preparation of the chitosan grafted poly (quaternary ammonium)/Fe3O4 nanoparticles and its adsorption performance for food yellow 3.

    PubMed

    Yu, Chen; Geng, Jianqiang; Zhuang, Yunxia; Zhao, Jian; Chu, Liqiu; Luo, Xiaoxuan; Zhao, Ying; Guo, Yanwen

    2016-11-01

    Chitosan and its derivatives can be used to modify magnetic materials to promote the adsorption properties of the magnetic materials and avoid the weakness of chitosan and its derivatives. In the present study, chitosan grafted poly(trimethyl allyl ammonium chloride) (CTS-g-PTMAAC) was prepared by graft copolymerization; then it was coated on the surfaces of the sodium citrate coated Fe3O4 nanoparticles (SC-Fe3O4) to prepare a novel composite CTS-g-PTMAAC/SC-Fe3O4 magnetic nanoparticles, with which possesses abundant surface positive charges. The structure and properties of the CTS-g-PTMAAC/SC-Fe3O4 composite magnetic nanoparticles were characterized by FTIR, TEM, VSM, and zeta potential. The dye adsorption characteristics of the CTS-g-PTMAAC/SC-Fe3O4 nanoparticles were determined using the food yellow 3 aqueous solutions as a model food effluent. Effect of pH of the dye solution on the adsorption of food yellow 3 was determined and compared with N-2-hydroxylpropyl trimethyl ammonium chloride chitosan coated sodium citrate-Fe3O4 (CTS-g-HTCC/SC-Fe3O4) composite magnetic nanoparticles. The adsorption kinetics, adsorption isotherms, adsorption thermodynamics, and desorption and reusability of the magnetic nanoparticles were investigated. PMID:27516279

  18. Doxorubicin-incorporated nanoparticles composed of poly(ethylene glycol)-grafted carboxymethyl chitosan and antitumor activity against glioma cells in vitro.

    PubMed

    Jeong, Young-Il; Jin, Shu-Guang; Kim, In-Young; Pei, Jian; Wen, Min; Jung, Tae-Young; Moon, Kyung-Sub; Jung, Shin

    2010-08-01

    In this study, methoxy poly(ethylene glycol)-grafted carboxymethyl chitosan (CMCPEG) was synthesized to make nanoparticles with doxorubicin (DOX) by ion complex formation. Since DOX has positive amine groups, it can interact with the carboxymethyl group of CMCPEG. The particle size of DOX-incorporated nanoparticles of CMCPEG was < 300 nm and nanoparticles had spherical shapes at morphological observation, indicating that DOX/CMCPEG mixtures can form spherical nanoparticles. In a drug release study, higher drug content induced an extended release of drug. Drug release was significantly changed by the release media pH. DOX release was faster at an acidic pH than a neutral or basic pH. The antitumor activity of DOX-incorporated nanoparticles in vitro was tested with DOX-resistant C6 glioma cells. Nanoparticles showed increased cytotoxicity compared to DOX alone. These results suggest that DOX was unable to penetrate into cells and did not effectively inhibit cell proliferation. In contrast, nanoparticles can penetrate into cells and effectively inhibit cell proliferation. Observation of cells under red fluorescence confirmed these results, i.e., nanoparticle-treated C6 cells, unlike DOX-treated cells, had strong red fluorescence. Since DOX has strong red fluorescence, DOX-incorporated nanoparticles entered into the tumor cells more than DOX alone. As a result, we suggest that DOX-incorporated nanoparticles of CMCPEG are superior candidates for antitumor drug delivery. PMID:20427160

  19. A novel reusable nanocomposite adsorbent, xanthated Fe3O4-chitosan grafted onto graphene oxide, for removing Cu(II) from aqueous solutions

    NASA Astrophysics Data System (ADS)

    Liu, Jinshui; Liu, Wenxiu; Wang, Yiru; Xu, Meijiao; Wang, Bin

    2016-03-01

    Novel nanocomposites of xanthated Fe3O4-chitosan grafted onto graphene oxide (xanthated Fe3O4-CS-GO) were successfully synthesized for the first time using an amidation reaction. The xanthated Fe3O4-CS-GO was used to remove Cu(II) from aqueous solutions. The xanthated Fe3O4-CS-GO was characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffractometry, and energy dispersive X-ray spectroscopy. The Cu(II) adsorption isotherms for the xanthated Fe3O4-CS-GO fitted the Langmuir isotherm model. The maximum Cu(II) adsorption capacity of the xanthated Fe3O4-CS-GO was 426.8 mg g-1, which is much higher than the maximum adsorption capacities of other adsorbents that have been described in the literature. This was attributed to xanthated Fe3O4-CS-GO having abundant functional groups. The xanthated Fe3O4-CS-GO could be regenerated using ethylene diamine tetraacetic acid, and could easily be removed from a liquid using an external magnetic field. These features would allow secondary pollution of the environment to be avoided more easily than is the case for other adsorbents. Cu(II) was adsorbed from aqueous solutions quickly and efficiently by the xanthated Fe3O4-CS-GO complex, suggesting that xanthated Fe3O4-CS-GO may be an ideal candidate for removing Cu(II) from wastewater.

  20. Electrospinning of curcumin loaded chitosan/poly (lactic acid) nanofilm and evaluation of its medicinal characteristics

    NASA Astrophysics Data System (ADS)

    Dhurai, Bhaarathi; Saraswathy, Nachimuthu; Maheswaran, Ramasamy; Sethupathi, Ponnusamy; Vanitha, Palanisamy; Vigneshwaran, Sukumar; Rameshbabu, Venugopal

    2013-12-01

    The curcumin loaded chitosan/poly (lactic acid) (PLA) nanofibers were produced using electrospinning. Box—Behnken experimental design was used for the optimization of variables (-1, 0, + 1 coded level) like chitosan/PLA strength (% w/v), curcumin strength (% w/v) and applied voltage (kV) to obtain uniform fiber diameter. The morphology of nanofibers was shown by SEM. Molecular interactions and the presence of each chemical compound of curcumin loaded chitosan/PLA fibers were characterized by FTIR and EDX analysis. Antioxidant, drug release and in vitro cytotoxicity tests were performed to evaluate the suitability of nanofibers that would be used for wound healing. In vivo wound healing studies on excision and incision wounds created on rat model showed significant reduction of wound area when compared to untreated. The better healing efficiency can be attributed to the presence of curcumin and chitosan.

  1. The properties of antimicrobial films derived from poly(lactic acid)/starch/chitosan blended matrix.

    PubMed

    Bie, Pingping; Liu, Peng; Yu, Long; Li, Xiaoxi; Chen, Ling; Xie, Fengwei

    2013-10-15

    An antimicrobial material with a slow release property was developed based on poly(lactic acid)/starch/chitosan blends, in which chitosan acted as an antimicrobial agent while PLA and starch together were used as a slow-releasing device. An increase in the starch content drastically improved the hydrophilicity of the blends, which was favorable for the diffusion of the embedded chitosan. Moreover, the release of chitosan was observed to occur in two stages, with a very fast release stage initially and a slow but durable release stage as the latter. These two stages exhibited the effectiveness and long residual action of antimicrobial property of the blends respectively, demonstrating the suitability to be used for foods with high water activity, such as fresh meat. The tensile and thermal properties further verified the promising use of the blend material in packaging. PMID:23987434

  2. Influence of the acid type in the production of chitosan films reinforced with bacterial nanocellulose.

    PubMed

    Velásquez-Cock, J; Ramírez, E; Betancourt, S; Putaux, J-L; Osorio, M; Castro, C; Gañán, P; Zuluaga, R

    2014-08-01

    Chitosan films reinforced with bacterial cellulose (BC) nanoribbons were studied to understand the influence of acid (acetic and lactic acids) on the reinforcing effect. For both acids, the maximum concentration of the reinforcing constituent was 5wt% with respect to the dry weight of chitosan. The infrared spectra, mechanical properties, morphology and antimicrobial activity of the films were analyzed. The results showed a difference between the acids in their behavior and effect on the reinforcement, with a tensile strength of 12.3MPa for the acetic acid films and 3.3MPa for the lactic acid films. Additionally, the bacterial inhibition tests were shown to be positive for the lactic acid films and negative for the acetic acid films. Therefore, exchanging the acid used in these films may be desirable for certain applications. PMID:24875317

  3. Correlating Physicochemical Properties of Boronic Acid-Chitosan Conjugates to Glucose Adsorption Sensitivity

    PubMed Central

    Asantewaa, Yaa; Aylott, Jonathan; Burley, Jonathan C.; Billa, Nashiru; Roberts, Clive J.

    2012-01-01

    Phenyl boronic acid (PBA), which is known to interact with glucose, was covalently bonded to chitosan by direct reductive N-alkylation of chitosan with 4-formylphenylboronic acid (4-FPBA). Evidence of PBA bonding on chitosan was assessed by FTIR, ToF-SIMS, SEM, DSC and glucose adsorption sensitivity measurements. FTIR spectra showed strong signals at 1560 and 630 cm−1 indicating the formation of p-substituted benzene. Similarly, ToF-SIMS analyses on the conjugates registered fragments of boron ion (B−) at 11.0 m/z whose intensity increased in proportion to 4-FPBA loading. The degree to which PBA was bonded to chitosan was related to the 4-FPBA load used in the reaction (termed F1 through to F6 with increasing 4-FPBA load). Glucose adsorption sensitivity to PBA-bonded chitosan was directly related to the amount of PBA functionality within the conjugates and the physical nature of the matrices (porous or crystalline). Topographic analysis by SEM revealed that PBA-chitosan conjugates F1, F2 and F3 have porous matrices and their sensitivity to glucose adsorption was directly proportional to the degree of PBA substitution onto chitosan. Conversely, conjugates F4, F5 and F6 appeared crystalline under SEM and glucose adsorption sensitivity decreased in proportion to amount of PBA bonded to chitosan. The crystalline nature of the conjugates was confirmed by DSC, where the exothermic event related to the melting of the bonded PBA moiety, occurred at 338 °C. Thus, decreased sensitivity to glucose adsorption by the conjugates can be ascribed to the crystallinity imparted by increased content of the bonded PBA moiety, providing an optimal loading of PBA in terms of maximizing response to glucose. PMID:24300397

  4. Formation of calcium carbonate films on chitosan substrates in the presence of polyacrylic acid

    SciTech Connect

    He, Linghao; Xue, Rui; Song, Rui

    2009-05-15

    In this investigation, chitosan membranes with different surface average degrees of deacetylation (DA) are prepared and then are employed as the support matrix to culture calcium carbonate (CaCO{sub 3}). In the presence of high concentration of polyacrylic acid (PAA), the CaCO{sub 3} films obtained on the surface of all chitosan films mainly consisted of vaterite, which suggests the presence of bulk PAA plays an overwhelming part in stabilizing the vaterite. As a comparison, the influences of active groups indicate that only in case of low concentration PAA the thin CaCO{sub 3} films grown on chitosan with 8% DA mainly consisted of vaterite owing to the strong nucleation ability of -NH{sub 2} group, whereas, for those grown on chitosan with 80% DA the CaCO{sub 3} films mainly consisted of aragonite. A more complex scenario revealed that in the case of intermediate concentration of PAA the formed polymorphs behave as mixtures of vaterite and aragonite. - Graphical abstract: Chitosan membranes with different degrees of deacetylation (DA) are employed as support to culture calcium carbonate (CaCO{sub 3}). In high concentration of polyacrylic acid (PAA), the CaCO{sub 3} films obtained consisted of vaterite. However, the CaCO{sub 3} film grown on chitosan with 8% DA mainly consisted of vaterite as opposed to aragonite for chitosan with 8% DA. The schematic presentation of the formation of calcium carbonate on chitosan films with different degrees of acetylation in the presence of PAA with low-, mid- and high concentrations.

  5. Enzymatic cross-linking of carboxymethylpullulan grafted with ferulic acid.

    PubMed

    Dulong, Virginie; Hadrich, Ahdi; Picton, Luc; Le Cerf, Didier

    2016-10-20

    Carboxymethylpullulan (CMP) has been modified in a two-step grafting reaction of ferulic acid (FA). Acid adipic dihydrazyde (ADH) was first reacted with FA activated with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC). Then the product of this first reaction was reacted with CMP (activated with EDC). Grafted polysaccharides structure was confirmed by FTIR and (1)H NMR spectroscopy. Analyses by size-exclusion chromatography (SEC) coupling on-line with a multi-angle light scattering detector (MALS), a viscometer and a differential refractive index detector (DRI) (SEC/MALS/DRI/Visco) showed that associations between FA moieties occurred due to hydrophobic interactions. The grafting rates of FA were determined by the Folin-Ciocalteu method and were found between 1.0% and 11.2% (mol/mol anhydroglucose unit). The CMP-FA were then enzymatically cross-linked with laccase from Pleurotus ostreatus. The crosslinking reactions were followed by rheological measurements, demonstrating the influence of laccase concentration on kinetics. Elastic modulus and swelling rates of hydrogels depends on FA content only for low values. PMID:27474545

  6. The influence of UV-irradiation on chitosan modified by the tannic acid addition.

    PubMed

    Sionkowska, A; Kaczmarek, B; Gnatowska, M; Kowalonek, J

    2015-07-01

    The influence of UV-irradiation with the wavelength 254 nm on the properties of chitosan modified by the tannic acid addition was studied. Tannic acid was added to chitosan solution in different weight ratios and after solvent evaporation thin films were formed. The properties of the films such as thermal stability, Young modulus, ultimate tensile strength, moisture content, swelling behavior before and after UV-irradiation were measured and compared. Moreover, the surface properties were studied by contact angle measurements and by the use of atomic force microscopy. The results showed that UV-irradiation caused both, the degradation of the specimen and its cross-linking. The surface of the films made of chitosan modified by the addition of tannic acid was altered by UV-irradiation. PMID:26002540

  7. Environmental applications of chitosan and its derivatives.

    PubMed

    Yong, Soon Kong; Shrivastava, Manoj; Srivastava, Prashant; Kunhikrishnan, Anitha; Bolan, Nanthi

    2015-01-01

    , hydraulic conductivity, permeability, surface area and sorption capacity. Crosslinked chitosan is an excellent sorbent for trace metals especially because of the high flexibility of its structural stability. Sorption of trace metals by chitosan is selective and independent of the size and hardness of metal ions, or the physical form of chitosan (e.g., film, powder and solution). Both -OH and -NH2 groups in chitosan provide vital binding sites for complexing metal cations. At low pH, -NH3 + groups attract and coagulate negatively charged contaminants such as metal oxyanions, humic acids and dye molecules. Grafting certain functional molecules into the chitin structure improves sorption capacity and selectivity for remediating specific metal ions. For example, introducing sulfur and nitrogen donor ligands to chitosan alters the sorption preference for metals. Low molecular weight chitosan derivatives have been used to remediate metal contaminated soil and sediments. They have also been applied in permeable reactive barriers to remediate metals in soil and groundwater. Both chitosan and modified chitosan have been used to phytoremediate metals; however, the mechanisms by which they assist in mobilizing metals are not yet well understood. In addition, microbes have been used in combination with chitosan to remediate metals (e.g., Cu and Zn) in contaminated soils. Chitosan has also been used to remediate organic contaminants, such as oil-based wastewater, dyes, tannins, humic acids, phenols, bisphenoi-A, p-benzoquinone, organo-phosphorus insecticides, among others. Chitosan has also been utilized to develop optical and electrochemical sensors for in-situ detection of trace contaminants. In sensor technology, naturally-derived chitosan is used primarily as an immobilizing agent that results from its enzyme compatibility, and stabilizing effect on nanoparticles. Contaminant-sensing agents, such as enzymes, microbes and nanoparticles, have been homogeneously immobilized in chitosan

  8. Nanoamphiphilic Chitosan Dispersed Poly(lactic acid) Bionanocomposite Films with Improved Thermal, Mechanical, and Gas Barrier Properties.

    PubMed

    Pal, Akhilesh Kumar; Katiyar, Vimal

    2016-08-01

    This article demonstrates the synthesis of lactic acid oligomer-grafted-chitosan (OLLA-g-CH), a nanoamphiphilic molecule, by in situ condensation polymerization and its effective use as a nanofiller for improvement in multiple properties of poly(lactic acid) (PLA) films, essential for stringent food packaging applications. Fourier transform infrared spectroscopy (FTIR) analysis shows the presence of amide-ester bond at 1539 cm(-1), which confirms the structural grafting of OLLA chains with chitosan molecules. This nanoamphiphilic OLLA-g-CH molecule act as surfactant containing hydrophilic chitosan head and hydrophobic OLLA tails with average size in the range of ∼2-4 nm. Prepared PLA/OLLA-g-CH bionanocomposite films appear with uniform dispersion of nanoamphiphilic OLLA-g-CH molecules with self-assembled micelles having size as low as ∼20 nm and as high as ∼150 nm with core-shell morphology in PLA matrix. This nanofiller is found very effective toward significant reduction in oxygen permeability (OP) by ∼10-fold due to the reduction in solubility of oxygen molecules and improvement in crystal nucleation density due to availability of nanonucleating sites. Ultimate tensile strength (UTS) of PLA/OLLA-g-CH bionanocomposite films are relatively comparable to that of PLA, however, elongation at break is improved significantly. The onset of thermal degradation of PLA/(OLLA-g-CH) films is also found comparable to that of PLA film. The glass transition temperature (Tg) of bionanocomposites is decreased by more than 18 °C with increase in OLLA-g-CH loading, which indicates the improved plasticization characteristics of PLA matrix. The crystallization kinetics suggest nonthree dimensional truncated spherical structures, which is controlled by the combination of thermal and athermal instantaneous nucleations. POM analysis suggested that the spherulite growth of PLA is improved significantly with the addition of OLLA-g-CH. The reduction in Tg of PLA with improvement

  9. Collagen tissue treated with chitosan solutions in carbonic acid for improved biological prosthetic heart valves.

    PubMed

    Gallyamov, Marat O; Chaschin, Ivan S; Khokhlova, Marina A; Grigorev, Timofey E; Bakuleva, Natalia P; Lyutova, Irina G; Kondratenko, Janna E; Badun, Gennadii A; Chernysheva, Maria G; Khokhlov, Alexei R

    2014-04-01

    Calcification of bovine pericardium dramatically shortens typical lifetimes of biological prosthetic heart valves and thus precludes their choice for younger patients. The aim of the present work is to demonstrate that the calcification is to be mitigated by means of treatment of bovine pericardium in solutions of chitosan in carbonic acid, i.e. water saturated with carbon dioxide at high pressure. This acidic aqueous fluid unusually combines antimicrobial properties with absolute biocompatibility as far as at normal pressure it decomposes spontaneously and completely into H2O and CO2. Yet, at high pressures it can protonate and dissolve chitosan materials with different degrees of acetylation (in the range of 16-33%, at least) without any further pretreatment. Even exposure of the bovine pericardium in pure carbonic acid solution without chitosan already favours certain reduction in calcification, somewhat improved mechanical properties, complete biocompatibility and evident antimicrobial activity of the treated collagen tissue. The reason may be due to high extraction ability of this peculiar compressed fluidic mixture. Moreover, exposure of the bovine pericardium in solutions of chitosan in carbonic acid introduces even better mechanical properties and highly pronounced antimicrobial activity of the modified collagen tissue against adherence and biofilm formation of relevant Gram-positive and Gram-negative strains. Yet, the most important achievement is the detected dramatic reduction in calcification for such modified collagen tissues in spite of the fact that the amount of the thus introduced chitosan is rather small (typically ca. 1wt.%), which has been reliably detected using original tritium labelling method. We believe that these improved properties are achieved due to particularly deep and uniform impregnation of the collagen matrix with chitosan from its pressurised solutions in carbonic acid. PMID:24582232

  10. Preparation and evaluation of inhalable itraconazole chitosan based polymeric micelles

    PubMed Central

    2012-01-01

    Background This study evaluated the potential of chitosan based polymeric micelles as a nanocarrier system for pulmonary delivery of itraconazole (ITRA). Methods Hydrophobically modified chitosan were synthesized by conjugation of stearic acid to the hydrophilic depolymerized chitosan. FTIR and 1HNMR were used to prove the chemical structure and physical properties of the depolymerized and the stearic acid grafted chitosan. ITRA was entrapped into the micelles and physicochemical properties of the micelles were investigated. Fluorescence spectroscopy, dynamic laser light scattering and transmission electron microscopy were used to characterize the physicochemical properties of the prepared micelles. The in vitro pulmonary profile of polymeric micelles was studied by an air-jet nebulizer connected to a twin stage impinger. Results The polymeric micelles prepared in this study could entrap up to 43.2±2.27 μg of ITRA per milliliter. All micelles showed mean diameter between 120–200 nm. The critical micelle concentration of the stearic acid grafted chitosan was found to be 1.58×10-2 mg/ml. The nebulization efficiency was up to 89% and the fine particle fraction (FPF) varied from 38% to 47%. The micelles had enough stability to remain encapsulation of the drug during nebulization process. Conclusions In vitro data showed that stearic acid grafted chitosan based polymeric micelles has a potential to be used as nanocarriers for delivery of itraconazole through inhalation. PMID:23351398

  11. Fibrous polymer grafted magnetic chitosan beads with strong poly(cation-exchange) groups for single step purification of lysozyme.

    PubMed

    Bayramoglu, Gulay; Tekinay, Turgay; Ozalp, V Cengiz; Arica, M Yakup

    2015-05-15

    Lysozyme is an important polypetide used in medical and food applications. We report a novel magnetic strong cation exchange beads for efficient purification of lysozyme from chicken egg white. Magnetic chitosan (MCHT) beads were synthesized via phase inversion method, and then grafted with poly(glycidyl methacrylate) (p(GMA)) via the surface-initiated atom transfer radical polymerization (SI-ATRP). Epoxy groups of the grafted polymer, were modified into strong cation-exchange groups (i.e., sulfonate groups) in the presence of sodium sulfite. The MCTH and MCTH-g-p(GMA)-SO3H beads were characterized by ATR-FTIR, SEM, and VSM. The sulphonate groups content of the modified MCTH-g-p(GMA)-4 beads was found to be 0.53mmolg(-1) of beads by the potentiometric titration method. The MCTH-g-p(GMA)-SO3H beads were first used as an ion-exchange support for adsorption of lysozyme from aqueous solution. The influence of different experimental parameters such as pH, contact time, and temperature on the adsorption process was evaluated. The maximum adsorption capacity was found to be 208.7mgg(-1) beads. Adsorption of lysozyme on the MCTH-g-p(GMA)-SO3H beads fitted to Langmuir isotherm model and followed the pseudo second-order kinetic. More than 93% of the adsorbed lysozyme was desorbed using Na2CO3 solution (pH 11.0). The purity of the lysozyme was checked by HPLC and SDS gel electrophoresis. In addition, the MCTH-g-p(GMA)-SO3H beads prepared in this work showed promising potential for separation of various anionic molecules. PMID:25864009

  12. Chitosan-graft-beta-cyclodextrin scaffolds with controlled drug release capability for tissue engineering applications.

    PubMed

    Prabaharan, M; Jayakumar, R

    2009-05-01

    Biodegradable scaffolds composed of chitosan-g-beta-cyclodextrin (chit-g-beta-CD) were prepared by freeze-drying method as synthetic extracellular matrices to fill the gap during the healing process. Due to the presence of beta-CD, these scaffolds can be used as a matrix for drug loading and controlled release. The morphology, swelling and drug release properties of the scaffolds were found to be dependent on the extent of cross-linking density in the scaffolds. The drug dissolution profile showed that chit-g-beta-CD scaffolds provided a slower release of the entrapped ketoprofen than chitosan scaffold. The MTT assay showed that there is no obvious cytotoxicity of chit-g-beta-CD scaffolds cross-linked with 0.01 M of glutaraldehyde against the fibroblasts (L929) cells. These results suggest that chit-g-beta-CD scaffolds may become a potential biodegradable active filling material with controlled drug release capability, which provide a healthy environment and enhance the surrounding tissue regeneration. PMID:19428461

  13. Galactosylation of chitosan-graft-spermine as a gene carrier for hepatocyte targeting in vitro and in vivo.

    PubMed

    Kim, Ji-Hye; Kim, You-Kyoung; Arash, Minai-Tehrani; Hong, Seong-Ho; Lee, Jae-Ho; Kang, Bit Na; Bang, Yong-Bin; Cho, Chong-Su; Yu, Dae-Yeul; Jiang, Hu-Lin; Cho, Myung-Haing

    2012-07-01

    Polyethyleneimine (PEI) has been described as a highly efficient gene carrier due to its efficient proton sponge effect within endosomes. However, many studies have demonstrated that PEI is toxic and associated with a lack of cell specificity despite high transfection efficiency. In order to minimize the toxicity of PEI, we prepared chitosan-graft-spermine (CHI-g-SPE) in a previous study. CHI-g-SPE showed low toxicity and high transfection efficiency. However, this compound also had limited target cell specificity. In the present study, we synthesized galactosylated CHI-g-SPE (GCS) because this modified GCS could be delivered specifically into the liver due to hepatocyte-specific galactose receptors. The DNA-binding properties of GCS at various copolymer/DNA weight ratios were evaluated by a gel retardation assay. The GCS copolymer exhibited significant DNA-binding ability and efficiently protected DNA from nuclease attack. Using energy-filtered transmission electron microscopy (EF-TEM), we observed dense spherical, nano-sized GCS/DNA complexes with a homogenous distribution. Most importantly, GCS was associated with remarkably low cytotoxicity compared to PEI in HepG2, HeLa, and A549 cells. Moreover, GCS carriers specifically delivered the gene-of-interest into hepatocytes in vitro as well as in vivo. Our results suggest that the novel GCS described here is a safe and highly efficient carrier for hepatocyte-targeted gene delivery. PMID:22966542

  14. Antibacterial and conductive injectable hydrogels based on quaternized chitosan-graft-polyaniline/oxidized dextran for tissue engineering.

    PubMed

    Zhao, Xin; Li, Peng; Guo, Baolin; Ma, Peter X

    2015-10-15

    Biomaterials with injectability, conductivity and antibacterial effect simultaneously have been rarely reported. Herein, we developed a new series of in situ forming antibacterial conductive degradable hydrogels using quaternized chitosan (QCS) grafted polyaniline with oxidized dextran as crosslinker. The chemical structures, morphologies, electrochemical property, conductivity, swelling ratio, rheological property, in vitro biodegradation and gelation time of hydrogels were characterized. Injectability was verified by in vivo subcutaneous injection on a Sprague Dawley rat. The antibacterial activity of the hydrogels was firstly evaluated employing antibacterial assay using Escherichia coli and Staphylococcus aureus in vitro. The hydrogels containing polyaniline showed enhanced antibacterial activity compared to QCS hydrogel, especially for hydrogels with 3 wt% polyaniline showing 95 kill% and 90kill% for E. coli and S. aureus, respectively. Compared with QCS hydrogel, the hydrogels with 3 wt% polyaniline still showed enhanced antibacterial activity for E. coli in vivo. The adipose-derived mesenchymal stem cells (ADMSCs) were used to evaluate the cytotoxicity of the hydrogels and hydrogels with polyaniline showed better cytocompatibility than QCS hydrogel. The electroactive hydrogels could significantly enhance the proliferation of C2C12 myoblasts compared to QCS hydrogel. This work opens the way to fabricate in situ forming antibacterial and electroactive degradable hydrogels as a new class of bioactive scaffolds for tissue regeneration applications. PMID:26272777

  15. Chitosan-based nanoparticles for rosmarinic acid ocular delivery--In vitro tests.

    PubMed

    da Silva, Sara Baptista; Ferreira, Domingos; Pintado, Manuela; Sarmento, Bruno

    2016-03-01

    In this study, chitosan nanoparticles were used to encapsulate antioxidant rosmarinic acid, Salvia officinalis (sage) and Satureja montana (savory) extracts as rosmarinic acid natural vehicles. The nanoparticles were prepared by ionic gelation using chitosan and sodium tripolyphosphate (TPP) in a mass ratio of 7:1, at pH 5.8. Particle size distribution analysis and transmission electron microscopy (TEM) confirmed the size ranging from 200 to 300 nm, while surface charge of nanoparticles ranged from 20 to 30 mV. Nanoparticles demonstrate to be safe without relevant cytotoxicity against retina pigment epithelium (ARPE-19) and human cornea cell line (HCE-T). The permeability study in HCE monolayer cell line showed an apparent permeability coefficient Papp of 3.41±0.99×10(-5) and 3.24±0.79×10(-5) cm/s for rosmarinic acid loaded chitosan nanoparticles and free in solution, respectively. In ARPE-19 monolayer cell line the Papp was 3.39±0.18×10(-5) and 3.60±0.05×10(-5) cm/s for rosmarinic acid loaded chitosan nanoparticles and free in solution, respectively. Considering the mucin interaction method, nanoparticles indicate mucoadhesive proprieties suggesting an increased retention time over the ocular mucosa after instillation. These nanoparticles may be promising drug delivery systems for ocular application in oxidative eye conditions. PMID:26645149

  16. Inactivation of Salmonella on tomato stem scars by edible chitosan and organic acid coatings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study investigated the efficacy of antimicrobial coatings on inactivation of Salmonella on the surface of tomato stem scars, which was inoculated with a four-strain cocktail of Salmonella (S. Montevideo. S. Newport. S. Saintpaul, and S. Typhimurium) and coated with acid-chitosan solutions. The ...

  17. Anti-obesity effects of chitosan and psyllium husk with L-ascorbic acid in guinea pigs.

    PubMed

    Jun, Sung Chul; Jung, Eun Young; Hong, Yang Hee; Park, Yooheon; Kang, Duk ho; Chang, Un Jae; Suh, Hyung Joo

    2012-04-01

    The aim of this study was to investigate whether L-Ascorbic acid would facilitate the anti-obesity effects of chitosan and psyllium husk in vivo. The study was carried out with male Hartley guinea pigs for 5 weeks. The results show that chitosan itself did not influence body weight gain and food efficiency ratio (FER). However, the addition of L-Ascorbic acid to chitosan decreased these parameters; the body weight gain and FER in the chitosan-2 group (high-fat diet group with 5 % chitosan containing 0.5 % L-Ascorbic acid) was significantly (p < 0.05) lower than that in F-controls (high-fat diet group), and was similar to that in controls (normal diet group). L-Ascorbic acid enhanced significantly (p < 0.05) the increases of total fecal weight and fecal fat excretion by chitosan. The addition of L-Ascorbic acid to psyllium husk did not differ from psyllium husk alone in terms of changes in weight gain, plasma lipid levels, and fat pad weight. We found that the addition of L-Ascorbic acid to chitosan influenced the reduction in body weight gain and FER, and the increase in total fecal weight and fecal fat excretion in guinea pigs fed a high-fat diet. PMID:23065836

  18. Radiation grafting of acrylic and methacrylic acid to cellulose fibers to impart high water sorbency

    SciTech Connect

    Zahran, A.H.; Williams, J.L.; Stannett, V.T.

    1980-04-01

    Acrylic and methacrylic acids have been directly grafted to rayon and cotton using the preirradiation technique with /sup 60/ Co gamma rays. The rate of grafting increased with increasing temperature and monomer concentration, as did the final degree of grafting. The amount and rate of grafting also increased with the total irradiation dose but tended to level off at higher doses, in agreement with the leveling off of the radical content reported previously. Methacrylic acid grafted more and faster than acrylic acid to both rayon and cotton. Methacrylic acid grafted more with rayon than cotton, but acrylic acid gave somewhat similar yields with both fibers. The water abosrbency of the grafted fibers depended strongly on their posttreatment. Decrystallizing with 70% zinc chloride or with hot sodium hydroxidy developed supersorbency. The two treatments in succession, respectively, gave the highest values. Metacrylic acid brought about less sorbency than the corrsponding acrylic acid grafts. Useful levels of grafting and supersorbency could be readily and practically achieved by the methods described.

  19. Fibrous polymer-grafted chitosan/clay composite beads as a carrier for immobilization of papain and its usability for mercury elimination.

    PubMed

    Metin, Ayşegül Ülkü; Alver, Erol

    2016-07-01

    Papain, which is an industrially important enzyme, has been immobilized on fibrous polymer-modified composite beads, namely poly(methacrylic acid)-grafted chitosan/clay. Characterization studies have been done using FTIR and SEM analysis. Operating parameters such as pH and initial concentration of papain have been varied to obtain the finest papain immobilized polymer-modified composite beads. The immobilization capacity of composite beads has been determined as 34.47 ± 1.18 (n = 3) mg/g. The proteolytic activity of immobilized papain was operated using bovine serum albumin (BSA) and maximum velocity (V max) and Michaelis-Menten constant (Km) values of the free and immobilized enzymes were determined using Lineweaver-Burk and Eadie-Hofstee equations. Usability of papain immobilized polymer-modified composite beads as adsorbents for the elimination of mercury was investigated. The maximum removal capacity of PIPMC beads has been found to be 4.88 ± 0.21 mg Hg/g when the initial metal concentration and weight of polymer-modified composite beads were 50 mg/L and 0.04 g at pH 7, respectively. Mercury removal performance of the papain immobilized polymer-modified composite beads was investigated in conjunction with Cu (II), Zn (II) and Cd (II) ions. The mercury adsorption capacity of papain immobilized polymer-modified composite beads was a slight reduction from 1.15 to 0.89 mg/g in presence of multiple metal salts. PMID:27013506

  20. High-Performance Capacitive Deionization Disinfection of Water with Graphene Oxide-graft-Quaternized Chitosan Nanohybrid Electrode Coating.

    PubMed

    Wang, Yilei; El-Deen, Ahmed G; Li, Peng; Oh, Bernice H L; Guo, Zanru; Khin, Mya Mya; Vikhe, Yogesh S; Wang, Jing; Hu, Rebecca G; Boom, Remko M; Kline, Kimberly A; Becker, David L; Duan, Hongwei; Chan-Park, Mary B

    2015-10-27

    Water disinfection materials should ideally be broad-spectrum-active, nonleachable, and noncontaminating to the liquid needing sterilization. Herein, we demonstrate a high-performance capacitive deionization disinfection (CDID) electrode made by coating an activated carbon (AC) electrode with cationic nanohybrids of graphene oxide-graft-quaternized chitosan (GO-QC). Our GO-QC/AC CDID electrode can achieve at least 99.9999% killing (i.e., 6 log reduction) of Escherichia coli in water flowing continuously through the CDID cell. Without the GO-QC coating, the AC electrode alone cannot kill the bacteria and adsorbs a much smaller fraction (<82.8 ± 1.8%) of E. coli from the same biocontaminated water. Our CDID process consists of alternating cycles of water disinfection followed by electrode regeneration, each a few minutes duration, so that this water disinfection process can be continuous and it only needs a small electrode voltage (2 V). With a typical brackish water biocontamination (with 10(4) CFU mL(-1) bacteria), the GO-QC/AC electrodes can kill 99.99% of the E. coli in water for 5 h. The disinfecting GO-QC is securely attached on the AC electrode surface, so that it is noncontaminating to water, unlike many other chemicals used today. The GO-QC nanohybrids have excellent intrinsic antimicrobial properties in suspension form. Further, the GO component contributes toward the needed surface conductivity of the CDID electrode. This CDID process offers an economical method toward ultrafast, contaminant-free, and continuous killing of bacteria in biocontaminated water. The proposed strategy introduces a green in situ disinfectant approach for water purification. PMID:26389519

  1. A comparison of eugenol and menthol on encapsulation characteristics with water-soluble quaternized β-cyclodextrin grafted chitosan.

    PubMed

    Phunpee, Sarunya; Saesoo, Somsak; Sramala, Issara; Jarussophon, Suwatchai; Sajomsang, Warayuth; Puttipipatkhachorn, Satit; Puttipipatkhajorn, Satit; Soottitantawat, Apinan; Ruktanonchai, Uracha Rungsardthong

    2016-03-01

    Two guest molecules (eugenol and (-)-menthol) were investigated on inclusion complex formation with water-soluble quaternized β-CD grafted with chitosan (QCD-g-CS). The inclusion complexes were prepared at varying mole ratios between eugenol or (-)-menthol and β-CD (substituted on QCD-g-CS) by a conventional shaking method and obtained as solid powder by freeze-drying process. The results showed that encapsulation efficiency %EE decreased with increasing of initial eugenol or (-)-menthol loading whereas %loading increased with increasing of initial eugenol or (-)-menthol loading. The results indicated that inclusion complex formation between eugenol and QCD-g-CS was more favorable than that of (-)-menthol. To clarify this mechanism, molecular dynamics simulations were performed to explore their binding energy, solvation energy and total free energy of those complexes. It was found that the total free energy (ΔG) of eugenol and (-)-menthol against QCD-g-CS (mole ratio of 1) in water-explicit system were -2108.91 kJ/mol and -344.45 kJ/mol, respectively. Moreover, molecular dynamic simulation of eugenol absorbed on surface QCD-g-CS (-205.73 kJ/mol) was shown to have a higher negative value than that of (-)-menthol on QCD-gCS (3182.31 kJ/mol). Furthermore, the release characteristics of the encapsulated powder were also investigated in simulated saliva pH 6.8 at 32 °C. The results suggested that (-)-menthol had higher release rate from the complexes than eugenol. In all cases, the release characteristics for those guest molecules could be characterized by the limited-diffusion kinetics. PMID:26552020

  2. Hyaluronic acid fat graft myringoplasty vs fat patch fat graft myringoplasty.

    PubMed

    Alzahrani, Musaed; Saliba, Issam

    2015-08-01

    We aim to compare the hyaluronic acid to fat graft myringoplasty (HAFGM) technique to a recently described modified-FGM (M-FGM) in the repair of tympanic membrane perforation (TMP). We also aim to evaluate the hearing level improvement postoperatively. We conducted a prospective study in an adult tertiary care center between 2012 and 2013. Adult patients presenting with simple TMP were operated on randomly using either HAFGM or M-FGM under local anesthesia in outpatients' settings. Success was considered when complete closure is achieved. Audiometric parameters were evaluated pre and postoperatively. Twenty-four patients were included in the study (HAFGM: 10 patients and M-FGM: 14 patients). Complete closure was achieved in 80 % in HAFGM vs 42.8 % in the M-FGM (p = 0.03). The study was abandoned due to the low success rate in first 14 patients of the M-FGM group. The pure tone audiometry was improved postoperatively in the HAFGM only. The study was aborted because of the unsatisfactory obtained results using the MFGM. It also shows the beneficial effect of hyaluronic acid application to FGM for a successful TMP repair. PMID:24633245

  3. 3D composites based on the blends of chitosan and collagen with the addition of hyaluronic acid.

    PubMed

    Sionkowska, Alina; Kaczmarek, Beata; Lewandowska, Katarzyna; Grabska, Sylwia; Pokrywczyńska, Marta; Kloskowski, Tomasz; Drewa, Tomasz

    2016-08-01

    3D porous composites based on blends of chitosan, collagen and hyaluronic acid were obtained through the lyophilization process. Mechanical properties, swelling behavior and thermal stability of the blends were studied. Moreover, SEM images were taken and the structure of the blends was studied. Biological properties of the materials obtained were investigated by analyzing of proliferation rate of fibroblast cells incubated with biomaterial extract using MTT assay (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide). The results showed that the properties of 3D composites based on the blends of chitosan and collagen were altered after the addition 1%, 2% and 5% of hyaluronic acid. Mechanical properties and thermal stability of chitosan/collagen blends were improved in the presence of hyaluronic acid in the composite. New 3D materials based on the blends of chitosan, collagen and hyaluronic acid were non-toxic and did not significantly affect cell morphology. PMID:27151670

  4. Macroporous chitosan hydrogels: Effects of sulfur on the loading and release behaviour of amino acid-based compounds.

    PubMed

    Elviri, Lisa; Asadzadeh, Maliheh; Cucinelli, Roberta; Bianchera, Annalisa; Bettini, Ruggero

    2015-11-01

    Chitosan is a biodegradable, biocompatible polymer of natural origin widely applied to the preparation of functional hydrogels suitable for controlled release of drugs, peptides and proteins. Non-covalent interactions, expecially ionic interactions, are the main driver of the loading and release behaviour of amino acids or peptides from chitosan hydrogels. With the aim to improve the understanding of the mechanisms governing the behaviour of chitosan hydrogels on peptide uptake and delivery, in this paper the attention was focused on the role played by sulfur on the interactions of chitosan hydrogels with sulfur-containing amino acids (AA) and peptides. Hence, loading and release experiments on cysteine, cystine and glutathione (SH containing amino acid, dipeptide and tripeptide, respectively) as well as on glycine and valine as apolar amino acids were carried out. For these puroses, chitosan hydrogels were prepared in an easy and reproducible manner by a freeze-gelation process on a poly-L-lysine coated support. The hydrogel surface pore size, uniformity and distribution were tested. Optimal results (D50 = 26 ± 4 μm) were obtained by using the poly-L-lysine positively-charged surface. The loading results gathered evidenced that the sulfur-containing molecules presented an increased absorption both in terms of rate and extent by chitosan hydrogels with respect to nonpolar amino acids, mainly due to ionic and hydrogen bond interactions. ATR-FTIR analysis carried out on chitosan hydrogels, with and without the AA related compounds to study putative interactions, supported these apparent sulfur-dependent results. Finally, chitosan hydrogels displayed excellent retention capabilities (AA release <5%) for all AA, strongly supporting the use of chitosan hydrogels as matrix for controlled drug release. PMID:26256323

  5. Composite particles formed by complexation of poly(methacrylic acid) - stabilized magnetic fluid with chitosan: Magnetic material for bioapplications.

    PubMed

    Safarik, Ivo; Stepanek, Miroslav; Uchman, Mariusz; Slouf, Miroslav; Baldikova, Eva; Nydlova, Leona; Pospiskova, Kristyna; Safarikova, Mirka

    2016-10-01

    A simple procedure for the synthesis of magnetic fluid (ferrofluid) stabilized by poly(methacrylic acid) has been developed. This ferrofluid was used to prepare a novel type of magnetically responsive chitosan-based composite material. Both ferrofluid and magnetic chitosan composite were characterized by a combination of microscopy (optical microscopy, TEM, SEM), scattering (static and dynamic light scattering, SANS) and spectroscopy (FTIR) techniques. Magnetic chitosan was found to be a perspective material for various bioapplications, especially as a magnetic carrier for immobilization of enzymes and cells. Lipase from Candida rugosa was covalently attached after cross-linking and activation of chitosan using glutaraldehyde. Baker's yeast cells (Saccharomyces cerevisiae) were incorporated into the chitosan composite during its preparation; both biocatalysts were active after reaction with appropriate substrates. PMID:27287146

  6. Preparation and evaluation of lysozyme-loaded nanoparticles coated with poly-γ-glutamic acid and chitosan.

    PubMed

    Liu, Yong; Sun, Yan; Xu, Yaoxing; Feng, Hai; Fu, Sida; Tang, Jiangwu; Liu, Wei; Sun, Dongchang; Jiang, Hua; Xu, Shaochun

    2013-08-01

    To improve the application of lysozymes, methods for coating lysozymes with poly-γ-glutamic acid and chitosan were studied. Several lysozyme-loaded chitosan/poly-γ-glutamic acid composite nanosystems for loading and controlling the release of lysozymes were established. The lysozyme loading content and efficiency of the different systems were examined. The antibacterial activity of the composite nanoparticles was also investigated. Results showed that when the lysozymes were coated with poly-γ-glutamic acid and further rewrapped with chitosan, smooth spherical composite nanoparticles were obtained; the loading efficiency and loading content reached 76% and 40%, respectively. The lysozyme release in vitro was slow and presented a two-stage programmed release. Antibacterial testing in vitro indicated that lysozyme-loaded nanoparticles coated with poly-γ-glutamic acid/chitosan had outstanding antibacterial activity. An obvious assembly of bacterial cells and composite nanoparticles was observed during co-incubation. Therefore, the poly-γ-glutamic acid/chitosan composite coating broadened the antibacterial spectrum of the composite lysozyme nanoreagent, and presented satisfactory antibacterial effect. The lysozyme-loaded chitosan/poly-γ-glutamic acid nanocoating system established in this research could provide reference for coating and controlled releasing of alkaline proteins. PMID:23628585

  7. Delivery of siRNA targeting tumor metabolism using non-covalent PEGylated chitosan nanoparticles: Identification of an optimal combination of ligand structure, linker and grafting method.

    PubMed

    Corbet, Cyril; Ragelle, Héloïse; Pourcelle, Vincent; Vanvarenberg, Kévin; Marchand-Brynaert, Jacqueline; Préat, Véronique; Feron, Olivier

    2016-02-10

    PEGylated chitosan-based nanoparticles offer attractive platforms for siRNA cocktail delivery into tumors. Still, therapeutic efficacy requires us to select a rational combination of siRNAs and an efficient tumor delivery after systemic administration. Here, we showed that non-covalent PEGylation of chitosan-based nanoparticles loaded with siRNA targeting two key transporters of energy fuels for cancer cells, namely the lactate transporter MCT1 and the glutamine transporter ASCT2, could lead to significant antitumor effects. As a ligand, we tested variations of the prototypical RGD peptidomimetic (RGDp). A higher siRNA delivery was obtained with naphthyridine-containing RGDp randomly conjugated on the PEG chain by clip photochemistry and the use of a lipophilic linker than when using traditional chain-end grafting and RGDp with a hydrophilic linker. The antiproliferative effects resulting from ASCT2 and MCT1 silencing were validated separately in vitro in conditions mimicking specific metabolic profiles of cancer cells and in vivo upon concomitant delivery. The combination of those siRNA and the selected components of targeted RGDp nanoparticles led to a dramatic tumor growth inhibition upon peri-tumoral but also systemic administration in mice. Altogether these data emphasize the convenience of using non-covalent PEGylated chitosan particles to produce sheddable stealth protection compatible with an efficient siRNA delivery in tumors. PMID:26699426

  8. New type of chitosan/2-hydroxypropyl-β-cyclodextrin composite membrane for gallic acid encapsulation and controlled release.

    PubMed

    Paun, Gabriela; Neagu, Elena; Tache, Andreia; Radu, G L

    2014-01-01

    A new type of chitosan/2-hydroxypropyl-β-cyclodextrin composite membrane have been developed for the encapsulation and controlled release of gallic acid. The morphology of the composite membrane was investigated by infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM), whereas swelling gallic acid and release properties were investigated by UV-visible spectroscopy. The release behavior with pH changes was also explored. The composite membrane based on chitosan/2-hydroxypropyl-β-cyclodextrin with gallic acid included showed improved antioxidant capacities compared to plain chitosan membrane. The information obtained in this study will facilitate the design and preparation of composite membrane based on chitosan and could open a wide range of applications, particularly its use as an antioxidant in food, food packaging, biomedical (biodegradable soft porous scaffolds for enhance the surrounding tissue regeneration), pharmaceutical and cosmetics industries. PMID:24664323

  9. A novel biocompatible hyaluronic acid-chitosan hybrid hydrogel for osteoarthrosis therapy.

    PubMed

    Kaderli, S; Boulocher, C; Pillet, E; Watrelot-Virieux, D; Rougemont, A L; Roger, T; Viguier, E; Gurny, R; Scapozza, L; Jordan, O

    2015-04-10

    A conventional therapy for the treatment of osteoarthrosis is intra-articular injection of hyaluronic acid, which requires repeated, frequent injections. To extend the viscosupplementation effect of hyaluronic acid, we propose to associate it with another biopolymer in the form of a hybrid hydrogel. Chitosan was chosen because of its structural similarity to synovial glycosaminoglycans, its anti-inflammatory effects and its ability to promote cartilage growth. To avoid polyelectrolyte aggregation and obtain transparent, homogeneous gels, chitosan was reacetylated to a 50% degree, and different salts and formulation buffers were investigated. The biocompatibility of the hybrid gels was tested in vitro on human arthrosic synoviocytes, and in vivo assessments were made 1 week after subcutaneous injection in rats and 1 month after intra-articular injection in rabbits. Hyaluronic acid-chitosan polyelectrolyte complexes were prevented by cationic complexation of the negative charges of hyaluronic acid. The different salts tested were found to alter the viscosity and thermal degradation of the gels. Good biocompatibility was observed in rats, although the calcium-containing formulation induced calcium deposits after 1 week. The sodium chloride formulation was further tested in rabbits and did not show acute clinical signs of pain or inflammation. Hybrid HA-Cs hydrogels may be a valuable alternative viscosupplementation agent. PMID:25666331

  10. Cell Penetrating Peptide Conjugated Chitosan for Enhanced Delivery of Nucleic Acid

    PubMed Central

    Layek, Buddhadev; Lipp, Lindsey; Singh, Jagdish

    2015-01-01

    Gene therapy is an emerging therapeutic strategy for the cure or treatment of a spectrum of genetic disorders. Nevertheless, advances in gene therapy are immensely reliant upon design of an efficient gene carrier that can deliver genetic cargoes into the desired cell populations. Among various nonviral gene delivery systems, chitosan-based carriers have gained increasing attention because of their high cationic charge density, excellent biocompatibility, nearly nonexistent cytotoxicity, negligible immune response, and ideal ability to undergo chemical conjugation. However, a major shortcoming of chitosan-based carriers is their poor cellular uptake, leading to inadequate transfection efficiency. The intrinsic feature of cell penetrating peptides (CPPs) for transporting diverse cargoes into multiple cell and tissue types in a safe manner suggests that they can be conjugated to chitosan for improving its transfection efficiency. In this review, we briefly discuss CPPs and their classification, and also the major mechanisms contributing to the cellular uptake of CPPs and cargo conjugates. We also discuss immense improvements for the delivery of nucleic acids using CPP-conjugated chitosan-based carriers with special emphasis on plasmid DNA and small interfering RNA. PMID:26690119

  11. Gadolinium diethylenetriaminopentaacetic acid-loaded chitosan microspheres for gadolinium neutron-capture therapy.

    PubMed

    Saha, Tapan Kumar; Ichikawa, Hideki; Fukumori, Yoshinobu

    2006-12-11

    In order to provide a suitable device that would contain water-soluble drugs, highly water-soluble gadolinium diethylenetriaminopentaacetic acid-loaded chitosan microspheres (CMS-Gd-DTPA) were prepared by the emulsion method using glutaraldehyde as a cross-linker and Span 80 as a surfactant for gadolinium neutron-capture therapy of cancer. The gadolinium content and the mass median diameter of CMS-Gd-DTPA were estimated. The size and morphology of the CMS-Gd-DTPA were strongly influenced by the initial applied weight ratio of Gd-DTPA:chitosan. FTIR spectra showed that the electrostatic interaction between chitosan and Gd-DTPA accelerated the formation of gadolinium-enriched chitosan microspheres. Sufficient amounts of glutaraldehyde and Span 80 were necessary for producing discrete CMS-Gd-DTPA. The CMS-Gd-DTPA having a mass median diameter 11.7microm and 11.6% of gadolinium could be used in Gd-NCT following intratumoral injection. PMID:17045253

  12. Reducing protein adsorption with polymer-grafted hyaluronic acid coatings.

    PubMed

    Ramadan, Mohamed H; Prata, Joseph E; Karácsony, Orsolya; Dunér, Gunnar; Washburn, Newell R

    2014-07-01

    We report a thermoresponsive chemical modification strategy of hyaluronic acid (HA) for coating onto a broad range of biomaterials without relying on chemical functionalization of the surface. Poly(di(ethylene glycol) methyl ether methacrylate) (PMEO2MA), a polymer with a lower critical solution temperature of 26 °C in water, was grafted onto HA to allow facile formation of biopolymer coatings. While the mechanism for film formation appears to involve a complex combination of homogeneous nucleation followed by heterogeneous film growth, we demonstrate that it resulted in hydrophilic coatings that significantly reduce protein adsorption despite the high fraction of hydrophobic (PMEO2MA). Structural characterization was performed using atomic force microscopy (AFM), which showed the formation of a dense, continuous coating based on 200 nm domains that were stable in protein solutions for at least 15 days. The coatings had a water contact angle of 16°, suggesting the formation of hydrophilic but not fully wetting films. Quartz crystal microbalance with dissipation monitoring (QCM-D) as well as biolayer interferometry (BLI) techniques were used to measure adsorption of bovine serum albumin (BSA), fibrinogen (Fbg), and human immunoglobulin (IgG), with results indicating that HA-PMEO2MA-coated surfaces effectively inhibited adsorption of all three serum proteins. These results are consistent with previous studies demonstrating that this degree of hydrophilicity is sufficient to generate an effectively nonfouling surface and suggest that segregation during the solubility transition resulted in a surface that presented the hydrophilic HA component of the hybrid biopolymer. We conclude that PMEO2MA-grafted HA is a versatile platform for the passivation of hydrophobic biomaterial surfaces without need for substrate functionalization. PMID:24892924

  13. The chitosan-gelatin (bio)polyelectrolyte complexes formation in an acidic medium.

    PubMed

    Voron'ko, Nicolay G; Derkach, Svetlana R; Kuchina, Yuliya A; Sokolan, Nina I

    2016-03-15

    The interaction of cationic polysaccharide chitosan and gelatin accompanied by the stoichiometric (bio)polyelectrolyte complexes formation has been studied by the methods of capillary viscometry, UV and FTIR spectroscopy and dispersion of light scattering. Complexes were formed in the aqueous phase, with pH being less than the isoelectric point of gelatin (pIgel). The particle size of the disperse phase increases along with the growth of the relative viscosity in comparison with sols of the individual components-polysaccharide and gelatin. Possible models and mechanism of (bio)polyelectrolyte complexes formation have been discussed. It was shown that the complex formation takes place not only due to the hydrogen bonds, but also due to the electrostatic interactions between the positively charged amino-groups of chitosan and negatively charged amino acid residues (glutamic Glu and aspartic Asp acids) of gelatin. PMID:26794762

  14. Chitosan-poly(acrylic) acid polyionic complex: in vivo study to demonstrate prolonged gastric retention.

    PubMed

    Torrado, Susana; Prada, Pablo; de la Torre, Paloma M; Torrado, Santiago

    2004-02-01

    The aim of this study was to develop a chitosan-poly(acrylic) acid based controlled drug release system for gastric antibiotic delivery. Different mixtures of amoxicillin (A), chitosan (CS), and poly(acrylic) acid (PAA) were employed to obtain these polyionic complexes. A non-invasive method was employed for determining the gastric residence time of the formulations. It was studied the swelling behavior and drug release from these complexes. Gastric emptying rate study was performed by means of the [13C]octanoic acid breath test. The gastric emptying rates of two different formulations (conventional and gastric retentive system) were studied. Swelling studies indicated that the extent of swelling was greater in the polyionic complexes than in the single chitosan formulations. The amoxicillin diffusion from the hydrogels was controlled by the polymer/drug interaction. The property of these complexes to control the solute diffusion depends on the network mesh size, which is a significant factor in the overall behavior of the hydrogels. The gastric half-emptying time of the polyionic complex was significantly delayed compared to the reference formulation, showing mean values of 164.32+/-26.72 and 65.06+/-11.50min, respectively (P<0.01). The results of this study suggest that, these polyionic complexes are good systems for specific gastric drug delivery. PMID:14609680

  15. Alpha-lipoic acid loaded in chitosan conduit enhances sciatic nerve regeneration in rat

    PubMed Central

    Azizi, Saeed; Heshmatian, Behnam; Amini, Keyvan; Raisi, Abbas; Azimzadeh, Mohammad

    2015-01-01

    Objective(s): To investigate the effect of topical administration of alpha-lipoic acid into chitosan conduit on peripheral nerve regeneration using a rat sciatic nerve transection model. Materials and Methods: Forty five Wistar rats were divided into three experimental groups randomly. A 10-mm gap of sciatic nerve was bridged with a chitosan conduit following surgical preparation and anesthesia. In treatment group, the conduit was filled with 30 µl alpha-lipoic acid (10 mg/kg/bw).It was filled with 30 µl phosphate buffered saline solution in control group. In Sham group sciatic nerve was just exposed. Results: The recovery of nerve function was faster in treatment group than in control, at 4 and 8 weeks after surgery (P-value<0.05). Conduction velocity was better in treatment group than in control group at 4 and 12 weeks (P-value<0.05). Recovery index was higher in treatment group than the control group, 8 weeks after surgery (P-value <0.05). Greater nerve fiber diameter, axon diameter, and myelin sheath thickness were observed in treatment group compared to control group at 8 and 12 weeks after surgery (P-value<0.05). The immunoreactivity of regenerated axons and myelin sheath in treatment group were far more similar to sham group. Conclusion: Alpha-lipoic acid when loaded in a chitosan conduit could improve transected sciatic nerve regeneration in rat. PMID:25945234

  16. Preparation of pure chitosan film using ternary solvents and its super absorbency.

    PubMed

    Wang, Xuejun; Lou, Tao; Zhao, Wenhua; Song, Guojun

    2016-11-20

    Chemical modification and graft copolymerization were commonly adopted to prepare super absorbent materials. However, physical microstructure of pure chitosan film was optimized to improve the water uptake capacity in this study. Chitosan films with micro-nanostructure were prepared by a ternary solvent system. The optimal process parameters are 1% acetic acid water solution: dioxane: dimethyl sulfoxide=90: 2.5: 7.5 (v/v/v) with chitosan concentration at 1.25% (w/v). The water uptake capacity of the chitosan film prepared under the optimal process parameters was 896g/g. The prepared chitosan films also exhibited high water uptake capacity in response to external stimuli such as temperature, pH and salt. This finding may provide another way for improving the water absorbency. The pure chitosan film may find potential applications especially in the fields of hygienic products and biomedicine due to its super water absorbency and nontoxicity. PMID:27561494

  17. Electron-beam induced RAFT-graft polymerization of poly(acrylic acid) onto PVDF

    NASA Astrophysics Data System (ADS)

    Grasselli, M.; Betz, N.

    2005-07-01

    This paper explores for the first time the post-radiation-induced-graft polymerization on solid substrate using reversible addition-fragmentation transfer (RAFT) mechanism. Radiation-induced graft polymerization onto polymers is a potentially interesting technique to create easily new materials from highly resistant polymers, e.g. surface graft polymerization of acrylic acid (AA) onto poly(vinylidene difluoride) (PVDF) improves its surface properties without losing its excellent mechanical properties. As a consequence of the radical nature of the polymerization processes it is difficult to control molecular weight of grafted chains, and therefore design and standardize the properties of the final product. RAFT polymerization is a suitable method to obtain monodisperse polymers. The ability of the RAFT agents to control the polymer chain length could be an interesting approach to improve the grafted polymers obtained by post-radiation-induced-graft polymerization technique. In this way, graft polymerization of AA onto electron-beam irradiated α-PVDF was performed using trithiocarbonic acid bis(1-phenylethyl) ester as a RAFT agent to control the radical polymerization. We studied several grafting parameters such as solvent, monomer concentration and grafting time in order to achieve a poly(acrylic acid) (PAA) layer onto PVDF surface. Acetic acid was found to be the best solvent for many reasons, as to drive graft polymerization mainly to the polymer surface, complete solubility and stability of all reactants. Hydrolysis of PAA chains was also studied in order to remove the trithiocarbonate functionality from the grafted polymer. A mild chemical condition was achieved in order to have thiol groups that were detected onto the modified PVDF by specific enzymatic reaction.

  18. Hyaluronic acid reagent functional chitosan-PEI conjugate with AQP2-siRNA suppressed endometriotic lesion formation

    PubMed Central

    Zhao, Meng-Dan; Cheng, Jin-Lin; Yan, Jing-Jing; Chen, Feng-Ying; Sheng, Jian-Zhong; Sun, Dong-Li; Chen, Jian; Miao, Jing; Zhang, Run-Ju; Zheng, Cai-Hong; Huang, He-Feng

    2016-01-01

    To identify a new drug candidate for treating endometriosis which has fewer side effects, a new polymeric nanoparticle gene delivery system consisting of polyethylenimine-grafted chitosan oligosaccharide (CSO-PEI) with hyaluronic acid (HA) and small interfering RNA (siRNA) was designed. There was no obvious difference in sizes observed between (CSO-PEI/siRNA)HA and CSO-PEI/siRNA, but the fluorescence accumulation in the endometriotic lesion was more significant for (CSO-PEI/siRNA)HA compared with CSO-PEI/siRNA due to the specific binding of HA to CD44. In addition, the (CSO-PEI/siRNA)HA nanoparticle gene therapy significantly decreased the endometriotic lesion sizes with atrophy and degeneration of the ectopic endometrium. The epithelial cells of ectopic endometrium from rat models of endometriosis showed a significantly lower CD44 expression than control after treatment with (CSO-PEI/siRNA)HA. Furthermore, observation under an electron microscope showed no obvious toxic effect on the reproductive organs. Therefore, (CSO-PEI/siRNA)HA gene delivery system can be used as an effective method for the treatment of endometriosis. PMID:27099493

  19. Fabrication of a bioadhesive transdermal device from chitosan and hyaluronic acid for the controlled release of lidocaine.

    PubMed

    Anirudhan, T S; Nair, Syam S; Nair, Anoop S

    2016-11-01

    A novel efficient transdermal (TD) lidocaine (LD) delivery device based on chitosan (CS) and hyaluronic acid (HA) was successfully developed in the present investigation. CS was grafted with glycidyl methacrylate (GMA) and butyl methacrylate (BMA) to fabricate a versatile material with improved adhesion and mechanical properties. HA was hydrophobically modified by covalently conjugating 3-(dimethylamino)-1-propylamine (DMPA) to encapsulate poorly water soluble LD and was uniformly dispersed in modified CS matrix. The prepared materials were characterized through FTIR, NMR, XRD, SEM, TEM and tensile assay. The dispersion of amine functionalized HA (AHA) on modified CS matrix offered strong matrix - filler interaction, which improved the mechanical properties and drug retention behavior of the device. In vitro skin permeation study of LD was performed with modified Franz diffusion cell using rat skin and exhibited controlled release. The influence of storage time on release profile was investigated and demonstrated that after the initial burst, LD release profile of the device after 30 and 60days storage was identical to that of a device which was not stored. In vivo skin adhesion test and skin irritation assay in human subjects, water vapor permeability and environmental fitness test was performed to judge its application in biomedical field. All results displayed that the fabricated device is a potential candidate for TD LD administration to the systemic circulation. PMID:27516320

  20. Protein absorption and fouling on poly(acrylic acid)-graft-polypropylene microfiltration membrane

    NASA Astrophysics Data System (ADS)

    Liu, Yanjun; Ma, Huiying; Lv, Chunying; Yang, Jia; Fu, Xueqi

    2009-07-01

    A series of pH-sensitive poly (acrylic acid)-graft-polypropylene hollow fiber microfiltration membranes were prepared by UV-photo-irradiation. Bovine serum albumin (BSA) was chosen as the model protein to investigate its absorption and fouling behaviors on membranes. The results showed that the hydrophilicity of grafted membrane was improved by poly(acrylic acid) chains with parts of membrane pores blocked. The grafted membranes were markedly pH-dependent on the water permeability as pH was altered from 1 to 11. The zeta potential of grafted membranes calculated by streaming potential was negative in most pH range. Electrostatic interaction energy calculated by DLVO theory showed the electric interaction force between grafted membrane and BSA was attractive. With the rise of grafting degree, the electric attractive force between grafted membrane and BSA increased as pH=3 and decreased as pH=8, while it kept basically unchanged as pH=4.7. As a result, most serious fouling was observed as pH=4.7. Grafted membranes had a lower BSA absorption and better antifouling behavior as pH=8, while the opposite result was revealed as pH=3. In conclusion, the absorption and fouling behavior of BSA on membranes was pH-dependent due to the pH-dependence of membrane charge, and the conformation of BSA and grafting chains.

  1. Synthesis, structure and phase transition property of acrylic acid grafted paraffin

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaowen; Liu, Pengfei; Ye, Lin

    2014-05-01

    Polar monomer acrylic acid (AA) was used to modify paraffin in order to improve the latent heat of paraffin as phase change materials. The composition and sequence structure of the grafted products were characterized by FTIR, 13C NMR, 1H NMR and GPC analysis, and the thermal properties of paraffin-g-AA were investigated. It was found that AA was confirmed to be grafted onto the molecular chain of paraffin successfully. The mechanism of free radical grafting of AA may be only monomeric grafts. At low grafting ratio, the structure B can be mainly formed as a result of the radical coupling termination; while at the high grafting ratio, structure A was the primary structure as a result of the radical chain growth process. The number-average molecular weight of the grafted samples increased at first but leveled off with increasing grafting ratio, while the weight-average molecular weight increased gradually. The latent heat capacity of the grafted paraffin can be improved obviously at low grafting ratio due to the formation of structure B.

  2. Surface Modification of PET Fabric by Graft Copolymerization with Acrylic Acid and Its Antibacterial Properties

    PubMed Central

    Abdolahifard, M.; Bahrami, S. Hajir; Malek, R. M. A.

    2011-01-01

    Graft copolymerization of acrylic acid (AA) onto Poly(ethylene terephthalate) (PET) fabrics with the aid of benzoyl peroxide was carried out. The effect of polymerization parameters on the graft yield was studied. Percent grafting was enhanced significantly by increasing benzoyl peroxide (BP) concentrations up to 3.84 g/lit and then decreased upon further increase in initiator concentration. Preswelling of PET leads to changes in its sorption-diffusion properties and favors an increase in the degree of grafting. The antibiotics treated grafted fabrics showed antibacterial properties towards gram-positive and gram-negative microorganisms. FTIR and SEM were used to characterize AA-grafted polyester fabrics. PMID:24052819

  3. Effect of chitosan dissolved in different acids on its ability to control postharvest gray mold of table grape.

    PubMed

    Romanazzi, Gianfranco; Gabler, Franka Mlikota; Margosan, Dennis; Mackey, Bruce E; Smilanick, Joseph L

    2009-09-01

    Chitosan is a natural biopolymer that must be dissolved in an acid solution to activate its antimicrobial and eliciting properties. Among 15 acids tested, chitosan dissolved in 1% solutions of acetic, L-ascorbic, formic, L-glutamic, hydrochloric, lactic, maleic, malic, phosphorous, and succinic acid. To control gray mold, table grape berries were immersed for 10 s in these chitosan solutions that had been adjusted to pH 5.6. The reduction in decay among single berries of several cultivars (Thompson Seedless, Autumn Seedless, and grape selection B36-55) inoculated with Botrytis cinerea at 1 x 10(5) conidia/ml before or after immersion in chitosan acetate or formate, followed by storage at 15 degrees C for 10 days, was approximately 70%. The acids alone at pH 5.6 did not control gray mold. Decay among clusters of two cultivars (Thompson Seedless and Crimson Seedless) inoculated before treatment was reduced approximately 60% after immersion in chitosan lactate or chitosan acetate followed by storage for 60 days at 0.5 degrees C. The viscosity of solutions was 1.9 centipoises (cp) (ascorbate) to 306.4 cp (maleicate) and the thickness of chitosan coating on berries was 4.4 microm (acetate) to 15.4 microm (ascorbate), neither of which was correlated with solution effectiveness. Chitosan acetate was the most effective treatment which effectively reduced gray mold at cold and ambient storage temperatures, decreased CO2 and O2 exchange, and did not injure the grape berries. PMID:19671004

  4. Preparation of molecularly imprinted resin based on chitosan for chiral recognition of S-mandelic acid.

    PubMed

    Monier, M; El-Mekabaty, A

    2013-04-01

    An enantioselective S-mandelic acid (S-MA) imprinted chitosan (SMIC) was prepared by cross-linking of chitosan using formaldehyde cross-linker, in the presence of S-MA as an imprint template molecule and 0.5% acetic acid solution as a solvent. Non-imprinted cross-linked chitosan (NIC) as control was also prepared by the same procedure in absence of template molecules. The surface morphology of both SMIC and NIC were examined by scanning electron microscope (SEM). SMIC particles were applied to determine the optimum operational condition for S-MA separation from dilute aqueous solution. In adsorption step, optimum pH and retention time were 3.5 and 60 min, while corresponding values in extraction step were 1 and 40 min, respectively. Also, the adsorption isotherms indicated that the maximum adsorption capacities of S- and R-MA on SMIC were 100 ± 0.5 and 64 ± 0.8 mg/g, respectively, while in the case of NIC, both R- and S-MA present the same maximum adsorption. PMID:23357795

  5. Synthesis and characterization of amylose grafted poly(acrylic acid) and its application in ammonia adsorption.

    PubMed

    Chen, Qing; Yu, Haojie; Wang, Li; Abdin, Zain-Ul; Yang, Xinpeng; Wang, Junhua; Zhou, Weidong; Zhang, Hongtao; Chen, Xiao

    2016-11-20

    Amylose grafted poly(acrylic acid) (Am-g-PAA) was synthesized by graft copolymerization of amylose with acrylic acid. The structure of Am-g-PAA was confirmed by (1)H NMR and FT-IR spectra. The morphology, crystallinity and thermal properties of amylose and Am-g-PAA were investigated by SEM, XRD and TGA, respectively. The highest degree of substitution (DS) of carboxyl group was 1.96 which was obtained after reacted for 1h at 60°C. Acrylic acid to anhydroglucose mole ratio for DS was 19.81. It was found that a large number of carboxyl groups were grafted on the backbone of amylose. It was also found that ammonia adsorption capacity of amylose increased by grafting poly(acrylic acid) on the backbone of amylose. PMID:27561514

  6. Chitosan as a green inhibitor for copper corrosion in acidic medium.

    PubMed

    El-Haddad, Mahmoud N

    2013-04-01

    The behavior of copper in 0.5 M HCl acid containing different concentrations of chitosan has been studied by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) measurements. Potentiodynamic polarization measurements show that the chitosan acts essentially as a mixed-type inhibitor. EFM can be used as a rapid and non destructive technique for corrosion rate measurements without prior knowledge of Tafel constants. The results of EIS indicate that the value of CPEs tends to decrease and both charge transfer resistance and inhibition efficiency tend to increase by increasing the inhibitor concentration. The investigated inhibitor has shown good inhibition efficiency in 0.5 M HCl. The adsorption of inhibitor on the copper surface obeys Langmuir's isotherm. Metal surface characterization was performed using scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR). Also, the relationship between quantum chemical calculations and experimental inhibition efficiency of the inhibitor was discussed. PMID:23298849

  7. Development and In Vivo Evaluation of Small-Diameter Vascular Grafts Engineered by Outgrowth Endothelial Cells and Electrospun Chitosan/Poly(ɛ-Caprolactone) Nanofibrous Scaffolds

    PubMed Central

    Zhou, Min; Qiao, Wei; Liu, Zhao; Shang, Tao; Qiao, Tong

    2014-01-01

    Successful engineering of a small-diameter vascular graft is still a challenge despite numerous attempts for decades. The present study aimed at developing a tissue-engineered vascular graft (TEVG) using autologous outgrowth endothelial cells (OECs) and a hybrid biodegradable polymer scaffold. OECs were harvested from canine peripheral blood and proliferated in vitro, as well as identified by immunofluorescent staining. Electrospun hybrid chitosan/poly(ɛ-caprolactone) (CS/PCL) nanofibers were fabricated and served as vascular scaffolds. TEVGs were constructed in vitro by seeding OECs onto CS/PCL scaffolds, and then implanted into carotid arteries of cell-donor dogs (n=6). After 3 months of implantation, 5 out of 6 of TEVGs remained patent as compared with 1 out of 6 of unseeded grafts kept patent. Histological and immunohistochemical analyses of the TEVGs retrieved at 3 months revealed the regeneration of endothelium, and the presence of collagen and elastin. OECs labeled with fluorescent dye before implantation were detected in the retrieved TEVGs, indicating that the OECs participated in the vascular tissue regeneration. Biomechanical testing of TEVGs showed good mechanical properties that were closer to native carotid arteries. RT-PCR and western blot analysis demonstrated that TEVGs had favorable biological functional properties resembling native arteries. Overall, this study provided a new strategy to develop small-diameter TEVGs with excellent biocompatibility and regeneration ability. PMID:23902162

  8. Grafting of poly (lactic acid) with maleic anhydride using supercritical carbon dioxide

    NASA Astrophysics Data System (ADS)

    Khankrua, R.; Pivsa-Art, S.; Hiroyuki, H.; Suttiruengwong, S.

    2015-07-01

    The aim of this work was to modify poly lactic acid (PLA) via free radical grafting with maleic anhydride (MA) by using supercritical carbon dioxide (SCCO2). Benzoyl peroxide (BPO) was used as an initiator. The solubility of MA in SCCO2 was first determined to estimate the suitable grafting conditions and equilibrium. From the solubility study of MA in SCCO2, it was found that the solubility of MA in SCCO2 increased with the increasing pressure and dissolution time. PLA films were first prepared by compression molding. The ratio of MA to BPO was 2:1. The reaction temperature and pressure were 70°C and 100 bar respectively. The grafting reaction and the degree of grafting were characterized by nuclear magnetic resonance (NMR) spectroscopy and titration, respectively. Scanning electron microscope (SEM) technique and contact angle were used to confirm the changes in physical properties of PLA film grafted MA. NMR spectrum indicated that the grafting of MA onto PLA was successively achieved. Degree of grafting by using SCCO2 was as high as 0.98%. This provided rather high grafting degree compared with other processes. SEM pictures showed the rough surface structure on modified PLA film. In addition, contact angle results showed an improvement of the hydrophilicity by maleic anhydride grafting onto polymers.

  9. Chitosan-hyaluronic acid/nano silver composite sponges for drug resistant bacteria infected diabetic wounds.

    PubMed

    Anisha, B S; Biswas, Raja; Chennazhi, K P; Jayakumar, R

    2013-11-01

    The aim of this work was to develop an antimicrobial sponge composed of chitosan, hyaluronic acid (HA) and nano silver (nAg) as a wound dressing for diabetic foot ulcers (DFU) infected with drug resistant bacteria. nAg (5-20 nm) was prepared and characterized. The nanocomposite sponges were prepared by homogenous mixing of chitosan, HA and nAg followed by freeze drying to obtain a flexible and porous structure. The prepared sponges were characterized using SEM and FT-IR. The porosity, swelling, biodegradation and haemostatic potential of the sponges were also studied. Antibacterial activity of the prepared sponges was analysed using Escherichia coli, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa and Klebsiella pneumonia. Chitosan-HA/nAg composite sponges showed potent antimicrobial property against the tested organisms. Sponges containing higher nAg (0.005%, 0.01% and 0.02%) concentrations showed antibacterial activity against MRSA. Cytotoxicity and cell attachment studies were done using human dermal fibroblast cells. The nanocomposite sponges showed a nAg concentration dependent toxicity towards fibroblast cells. Our results suggest that this nanocomposite sponges could be used as a potential material for wound dressing for DFU infected with antibiotic resistant bacteria if the optimal concentration of nAg exhibiting antibacterial action with least toxicity towards mammalian cells is identified. PMID:24060281

  10. Nanofibrous poly(acrylonitrile-co-maleic acid) membranes functionalized with gelatin and chitosan for lipase immobilization.

    PubMed

    Ye, Peng; Xu, Zhi-Kang; Wu, Jian; Innocent, Christophe; Seta, Patrick

    2006-08-01

    Nanofibrous membranes with an average diameter of 100 and 180 nm were fabricated from poly(acrylonitrile-co-maleic acid) (PANCMA) by the electrospinning process. These nanofibrous membranes contain reactive groups which can be used to covalently immobilize biomacromolecules. Two natural macromolecules, chitosan and gelatin, were tethered on these nanofibrous membranes to fabricate dual-layer biomimetic supports for enzyme immobilization in the presence of 1-ethyl-3-(dimethyl-aminopropyl) carbodiimide hydrochloride (EDC)/N-hydroxyl succinimide (NHS). Lipase from Candida rugosa was then immobilized on these dual-layer biomimetic supports using glutaraldehyde (GA), and on the nascent PANCMA fibrous membrane using EDC/NHS as coupling agent, respectively. The properties of the immobilized lipases were assayed. It was found that there is an increase of the activity retention of the immobilized lipase on the chitosan-modified nanofibrous membrane (45.6+/-1.8%) and on the gelatin-modified one (49.7+/-1.8%), compared to that on the nascent one (37.6+/-1.8%). The kinetic parameters of the free and immobilized lipases, K(m) and V(max), were also assayed. In comparison with the immobilized lipase on the nascent nanofibrous membrane, there is an increase of the V(max) value for the immobilized lipases on the chitosan- and gelatin-modified nanofibrous membranes. Results also indicate that the pH and thermal stabilities of lipases increase upon immobilization. The residual activities of the immobilized lipases are 55% on the chitosan-modified nanofibrous membrane and 60% on the gelatin-modified one, after 10 uses. PMID:16584770

  11. Preparation of molecularly imprinted cross-linked chitosan/glutaraldehyde resin for enantioselective separation of L-glutamic acid.

    PubMed

    Monier, M; El-Sokkary, A M A

    2010-08-01

    In the present study, separation of L-glutamic acid from dilute aqueous solution by solid-phase extraction based on molecular imprinting technique using cross-linked chitosan/glutaraldehyde resin was investigated. L-Glutamic acid imprinted cross-linked chitosan (LGIC) was prepared by cross-linking of chitosan by glutaraldehyde cross-linker, in the presence of L-glutamic acid. Non-imprinted cross-linked chitosan (NIC) as control was also prepared by the same procedure in the absence of template molecules. The morphological structures of both LGIC and NIC were examined by scanning electron microscope (SEM). LGIC particles were applied to determine the optimum operational condition for l-glutamic acid separation from dilute aqueous solution. In adsorption step, optimum pH and retention time were 5.5 and 100 min, while corresponding values in extraction step were 2.5 and 60 min, respectively. The adsorption isotherms indicated that the maximum adsorption capacities of L- and D-glutamic acid on LGIC were 42+/-0.8 and 26+/-1.2mg/g, respectively, while in case of NIC, both L- and D-glutamic acid present the same maximum adsorption capacity 7+/-0.6 mg/g, which confirm that the molecular imprinting technique creates an enantioselectivity of LGIC toward L-glutamic acid. In addition, chiral resolution of l-, d-glutamic acid racemic mixture was carried out using column of LGIC. PMID:20441776

  12. Hydrophobization and antimicrobial activity of chitosan and paper-based packaging material.

    PubMed

    Bordenave, Nicolas; Grelier, Stephane; Coma, Veronique

    2010-01-11

    This study reports the elaboration of water-resistant, antimicrobial, chitosan and paper-based materials as environmentally friendly food packaging materials. Two types of papers were coated with chitosan-palmitic acid emulsions or with a blend of chitosan and O,O'-dipalmitoylchitosan (DPCT). Micromorphology studies showed that inclusion of hydrophobic compounds into the chitosan matrix was enhanced by grafting them onto chitosan and that this led to their penetration of the paper's core. Compared to chitosan-coated papers, the coating of chitosan-palmitic emulsion kept vapor-barrier properties unchanged (239 and 170 g.m(-2).d(-1) versus 241 and 161 g.m(-2).d(-1)), while the coating of chitosan-DPCT emulsion dramatically deteriorated them (441 and 442 g.m(-2).d(-1)). However, contact angle measurements (110-120 degrees after 1 min) and penetration dynamics analysis showed that both strategies improved liquid-water resistance of the materials. Kit-test showed that all hydrophobized chitosan-coated papers kept good grease barrier properties (degree of resistance 6-8/12). Finally, all chitosan-coated materials exhibited over 98% inhibition on Salmonella Typhimurium and Listeria monocytogenes . PMID:19994882

  13. Novel procedure to enhance PLA surface properties by chitosan irreversible immobilization

    NASA Astrophysics Data System (ADS)

    Stoleru, Elena; Dumitriu, Raluca Petronela; Munteanu, Bogdanel Silvestru; Zaharescu, Traian; Tănase, Elisabeta Elena; Mitelut, Amalia; Ailiesei, Gabriela-Liliana; Vasile, Cornelia

    2016-03-01

    A novel two step procedure was applied for poly(lactic acid) (PLA) functionalization consisting in the exposure to cold radiofrequency plasma in nitrogen atmosphere or to gamma irradiation followed by "grafting to" of a chitosan layer using carbodiimide chemistry. The adhesion and stability of the deposited surface layer was assured by plasma/gamma irradiation treatment while the chitosan layer offers antifungal/antibacterial/antioxidant activities. Chitosan with different viscosities/deacetylation degree was deposited by electrospinning or immersion methods. Correlations between rheological behavior of chitosan solutions and chitosan layer deposition conditions are made. The PLA surface properties were investigated by water contact angle measurements, ATR-FTIR spectroscopy, AFM, chemiluminiscence, etc. It has been established that the surface roughness increases direct proportional with cold plasma duration and gamma irradiation dose and further increases by chitosan coating which at its turn depends on chitosan characteristics (viscosity and deacetylation degree) and method of deposition. Nano-fibers with relatively homogeneous and reproducible features are obtained by electrospinning of highly viscous chitosan while with the other two types of chitosan both microparticles and nano-fibers are formed. The chitosan coating obtained by immersion is more homogenous and compact and has a better antibacterial activity than the electrospun layer as fiber meshes.

  14. Ascorbic acid improves embryonic cardiomyoblast cell survival and promotes vascularization in potential myocardial grafts in vivo.

    PubMed

    Martinez, Eliana C; Wang, Jing; Gan, Shu Uin; Singh, Rajeev; Lee, Chuen Neng; Kofidis, Theo

    2010-04-01

    Organ restoration via cell therapy and tissue transplantation is limited by impaired graft survival. We tested the hypothesis that ascorbic acid (AA) reduces cell death in myocardial grafts both in vitro and in vivo and introduced a new model of autologous graft vascularization for later transplantation. Luciferase (Fluc)- and green fluorescent protein (GFP)-expressing H9C2 cardiomyoblasts were seeded in gelatin scaffolds to form myocardial artificial grafts (MAGs). MAGs were supplemented with AA (5 or 50 mumol/L) or plain growth medium. Bioluminescence imaging showed increased cell photon emission from day 1 to 5 in grafts supplemented with 5 mumol/L (p < 0.001) and 50 mumol/L (p < 0.01) AA. The amount of apoptotic cells in plain MAGs was significantly higher than in AA-enriched grafts. In our in vitro model, AA also enhanced H9C2 cell myogenic differentiation. For in vivo studies, MAGs containing H9C2-GFP-Fluc cells and enriched with AA (n = 10) or phosphate-buffered saline (n = 10) were implanted in the renal pouch of Wistar rats. At day 6, postimplantation bioluminescence signals decreased by 74% of baseline in plain MAGs versus 36% in AA-enriched MAGs (p < 0.0001). AA grafts contained significantly higher amounts of blood vessels, GFP(+) donor cells, and endothelial cells. In this study, we identified AA as a potent supplement that improves cardiomyoblast survival and promotes neovascularization in bioartificial grafts. PMID:19908964

  15. Monosaccharide compositions of sulfated chitosans obtained by analysis of nitrous acid degraded and pyrazolone-labeled products.

    PubMed

    Han, Zhangrun; Zeng, Yangyang; Zhang, Meng; Zhang, Yiran; Zhang, Lijuan

    2016-01-20

    Chemically sulfated chitosans are important biomaterials. However, a reliable analytical method for quality control over such compounds is still lacking. In this study, we prepared four different kinds of selectively sulfated chitosans and developed a novel method to analyze their monosaccharide compositions by HPLC. In this method, nitrous acid was used to generate 2, 5-hydro mannose (M), 3-O-sulfated M (M3), 6-O-sulfated M (M6), and 3, 6-O-disulfated M (M9) from the sulfated chitosans. PMP, that is 1-phenyl-3-methyl-5-pyrazolone with a UV absorbance at 245 nm, was used to label all the Ms quantitatively. The monosaccharide compositions for each sulfated chitosan were obtained by C18 HPLC separation and online UV detection of all PMP-labeled Ms. The identities of all Ms were confirmed by MS analysis with the help of standard Ms generated from a heparin pentasaccharide and chitosan. The overall results indicated that the newly developed method had advantages over (13)C NMR in defining the monosaccharide compositions of sulfated chitosans and was useful for quality control purpose. PMID:26572367

  16. Structure-function properties of amylose-oleic acid inclusion complexes grafted with poly(methyl acrylate)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spherulites, produced by steam jet-cooking high-amylose starch and oleic acid, were grafted with methyl acrylate, both before and after removal of un-complexed amylopectin. For comparison, granular high-amylose corn starch was graft polymerized in a similar manner. The amount of grafted and ungrafte...

  17. Layer-by-layer hyaluronic acid-chitosan coating promoted new collagen ingrowth into a poly(ethylene terephthalate) artificial ligament in a rabbit medical collateral ligament (MCL) reconstruction model.

    PubMed

    Li, Hong; Jiang, Jia; Ge, Yunsheng; Xu, Jialing; Zhang, Pengyun; Zhong, Wei; Chen, Shiyi

    2013-01-01

    The ideal artificial ligament graft should have favorable biocompatibility to facilitate cell adhesion, proliferation, and collagen regeneration. In this present study, surface modification was performed on a poly(ethylene terephthalate) (PET) artificial ligament graft by layer-by-layer (LBL) self-assembly coating of hyaluronic acid (HA) and chitosan (CS). The surface characterization of the ligament was examined using scanning electron microscopy, atomic force microscopy, and energy-dispersive X-ray spectroscopy. The results of in vitro culturing of human foreskin fibroblast cells supported the hypothesis that the LBL coating of CS-HA could promote the cell proliferation and adhesion on the sheets. A rabbit medical collateral ligament reconstruction model was used to evaluate the effect of this LBL coating in vivo. The final results proved that this LBL coating could significantly promote and enhance new collagen formation among the graft fibers. On the basis of these results, we conclude that such CS-HA assembly coating could enhance PET graft biocompatibility in vitro and in vivo, and a CS-HA-coated PET graft has considerable potential as a desirable substitute for ligament reconstruction. PMID:23565685

  18. Hg(II) removal from water by chitosan and chitosan derivatives: a review.

    PubMed

    Miretzky, P; Cirelli, A Fernandez

    2009-08-15

    Mercury (Hg) is one of the most toxic heavy metals commonly found in the global environment. Its toxicity is related to the capacity of its compounds to bioconcentrate in organisms and to biomagnify through food chain. A wide range of adsorbents has been used for removing Hg(II) from contaminated water. Chitosan is obtained by alkaline deacetylation of chitin. The adsorption capacity of chitosan depends on the origin of the polysaccharide, and on the experimental conditions in the preparation, that determine the degree of deacetylation. A great number of chitosan derivatives have been obtained by crosslinking with glutaraldehyde or epichlorohydrin among others or by grafting new functional groups on the chitosan backbone with the aim of adsorbing Hg(II). The new functional groups are incorporated to change the pH range for Hg(II) sorption and/or to change the sorption sites in order to increase sorption selectivity. The chemical modification affords a wide range of derivatives with modified properties for specific applications. Hg(II) adsorption on chitosan or chitosan derivatives is now assumed to occur through several single or mixed interactions: chelation or coordination on amino groups in a pendant fashion or in combination with vicinal hydroxyl groups, electrostatic attraction in acidic media or ion exchange with protonated amino groups. This review reports the recent developments in the Hg(II) removal in waste water treatment, using chitosan and its derivatives in order to provide useful information about the different technologies. When possibly the adsorption capacity of chitosan and chitosan derivatives under different experimental conditions is reported to help to compare the efficacy of the Hg(II) removal process. A comparison with the adsorption capacity of other low-cost adsorbents is also tabled. PMID:19232467

  19. Polyphenol-chitosan conjugates: Synthesis, characterization, and applications.

    PubMed

    Hu, Qiaobin; Luo, Yangchao

    2016-10-20

    Chitosan, the only positively charged polysaccharide in the world, is very attractive for food, medicinal and pharmaceutical applications because of its promising properties, including non-toxicity, superb biodegradability, high biocompatibility, abundant availability and low cost. In order to overcome the poor water solubility and widen the applications of chitosan, various polyphenol-chitosan conjugates have been synthesized in recent years. The present review focuses on the chitosan-based conjugates formed using different polyphenols, including gallic acid, caffeic acid, ferulic acid, salicylic acid, catechin, and EGGE, etc. Three major synthesis techniques, namely, activated ester-mediated modification, enzyme-mediated strategy, and free radical induced grafting approach are introduced in detail. In addition, the new physicochemical and biological properties of polyphenol-chitosan conjugates are introduced, including water solubility, thermo stability, in vitro and in vivo antioxidant activity, antimicrobial and anticancer activity. Furthermore, the novel applications of each conjugate are discussed in detail. Lastly, the challenges and prospective areas of study related to polyphenol-chitosan are summarized. PMID:27474608

  20. Design, characterization and in vitro evaluation of 5-aminosalicylic acid loaded N-succinyl-chitosan microparticles for colon specific delivery.

    PubMed

    Mura, C; Nácher, A; Merino, V; Merino-Sanjuán, M; Manconi, M; Loy, G; Fadda, A M; Díez-Sales, O

    2012-06-01

    The objective of this study was to prepare NS-chitosan microparticles for the delivery of 5-aminosalicylic acid (5-ASA) to the colon. Microparticles can spread out over a large area of colon allowing a more effective local efficacy of 5-ASA. N-Succinyl-chitosan was chosen as carrier system because of its excellent pharmaceutical properties in colon drug targeting such as poor solubility in acid environment, biocompatibility, mucoadhesive properties, and low toxicity. It was prepared by introducing succinic group into chitosan N-terminals of the glucosamine units. 5-ASA loaded NS-chitosan microparticles were prepared using spray-drying. As a control, a matrix obtained by freeze-drying technique was also prepared and tested. Fourier transform infrared (FT-IR), differential scanning calorimetry (DSC) and X-ray diffraction studies show the 5-ASA/NS-chitosan electrostatic interactions in both the systems. Mean size of the microparticles was around 5 μm, zeta potential value of both systems was always negative. Scanning electron microscopy (SEM) images show an acceptable spherical non porous structure of microparticles. In vitro swelling and drug release studies were in accordance with the polymer properties, showing the highest swelling ratio and drug release at pH=7.4 (colonic pH) where microparticles were able to deliver more than 90% of 5-ASA during 24h experiments. Rheological studies are in accordance with the swelling and release studies. PMID:22341520

  1. Starch-based Antimicrobial Films Incorporated with Lauric Acid and Chitosan

    NASA Astrophysics Data System (ADS)

    Salleh, E.; Muhamad, I. I.

    2010-03-01

    Antimicrobial (AM) packaging is one of the most promising active packaging systems. Starch-based film is considered an economical material for antimicrobial packaging. This study aimed at the development of food packaging based on wheat starch incorporated with lauric acid and chitosan as antimicrobial agents. The purpose is to restrain or inhibit the growth of spoilage and/or pathogenic microorganisms that are contaminating foods. The antimicrobial effect was tested on B. substilis and E. coli. Inhibition of bacterial growth was examined using two methods, i.e. zone of inhibition test on solid media and liquid culture test (optical density measurements). The control and AM films (incorporated with chitosan and lauric acid) were produced by casting method. From the observations, AM films exhibited inhibitory zones. Interestingly, a wide clear zone on solid media was observed for B. substilis growth inhibition whereas inhibition for E. coli was not as effective as B. substilis. From the liquid culture test, the AM films clearly demonstrated a better inhibition against B. substilis than E. coli.

  2. Reduction of acidity and removal of metal ions from coal mining effluents using chitosan microspheres.

    PubMed

    Laus, Rogério; Geremias, Reginaldo; Vasconcelos, Helder L; Laranjeira, Mauro C M; Fávere, Valfredo T

    2007-10-22

    Effluents from coal mining operations are not only highly acid but also depict elevated concentrations of metals which may contaminate the environment. Due to the polybasic characteristic of chitosan, this biopolymer is capable of both neutralizing and removing iron, aluminum and copper ions from such effluents. The present study aimed at evaluating the use of chitosan microspheres for their importance in continuous systems. The microspheres were prepared by the phase inversion method. Their average diameter and morphology were determined. Water samples from decantation pool (DP) and acidic mine drainage (AMD) effluents were treated using different amounts of microspheres. The pH and concentration of Fe, Al and Cu ions were evaluated both before and after treatment of effluent samples. The results revealed that the microspheres were capable of increasing the pH of DP and AMD samples from 2.34 and 2.58, respectively, to 6.20, i.e., close to neutrality. The treatment also resulted in full removal of the metals investigated. PMID:17499431

  3. Hyaluronic acid enhancement of expanded polytetrafluoroethylene for small diameter vascular grafts

    NASA Astrophysics Data System (ADS)

    Lewis, Nicole R.

    Cardiovascular disease is the leading cause of mortality and morbidity in the United States and other developed countries. In the United States alone, 8 million people are diagnosed with peripheral arterial disease per year and over 250,000 patients have coronary bypass surgery each year. Autologous blood vessels are the standard graft used in small diameter (<6mm) arterial bypass procedures. Synthetic small diameter grafts have had limited success. While polyethylene (Dacron) and expanded polytetrafluoroethylene (ePTFE) are the most commonly used small diameter synthetic vascular graft materials, there are significant limitations that make these materials unfavorable for use in the low blood flow conditions of the small diameter arteries. Specifically, Dacron and ePTFE grafts display failure due to early thrombosis or late intimal hyperplasia. With the shortage of tissue donors and the limited supply of autologous blood vessels available, there is a need for a small diameter synthetic vascular graft alternative. The aim of this research is to create and characterize ePTFE grafts prepared with hyaluronic acid (HA), evaluate thrombogenic potential of ePTFE-HA grafts, and evaluate graft mechanical properties and coating durability. The results in this work indicate the successful production of ePTFE-HA materials using a solvent infiltration technique. Surface interactions with blood show increased platelet adhesion on HA-modified surfaces, though evidence may suggest less platelet activation and erythrocyte lysis. Significant changes in mechanical properties of HA-modified ePTFE materials were observed. Further investigation into solvent selection, uniformity of HA, endothelialization, and dynamic flow testing would be beneficial in the evaluation of these materials for use in small diameter vascular graft bypass procedures.

  4. Green synthesis of silver and copper nanoparticles using ascorbic acid and chitosan for antimicrobial applications.

    PubMed

    Zain, N Mat; Stapley, A G F; Shama, G

    2014-11-01

    Silver and copper nanoparticles were produced by chemical reduction of their respective nitrates by ascorbic acid in the presence of chitosan using microwave heating. Particle size was shown to increase by increasing the concentration of nitrate and reducing the chitosan concentration. Surface zeta potentials were positive for all nanoparticles produced and these varied from 27.8 to 33.8 mV. Antibacterial activities of Ag, Cu, mixtures of Ag and Cu, and Ag/Cu bimetallic nanoparticles were tested using Bacillus subtilis and Escherichia coli. Of the two, B. subtilis proved more susceptible under all conditions investigated. Silver nanoparticles displayed higher activity than copper nanoparticles and mixtures of nanoparticles of the same mean particle size. However when compared on an equal concentration basis Cu nanoparticles proved more lethal to the bacteria due to a higher surface area. The highest antibacterial activity was obtained with bimetallic Ag/Cu nanoparticles with minimum inhibitory concentrations (MIC) of 0.054 and 0.076 mg/L against B. subtilis and E. coli, respectively. PMID:25129735

  5. Polyelectrolyte complexes via desalting mixtures of hyaluronic acid and chitosan-Physicochemical study and structural analysis.

    PubMed

    Lalevée, G; Sudre, G; Montembault, A; Meadows, J; Malaise, S; Crépet, A; David, L; Delair, T

    2016-12-10

    Polyelectrolyte complexes (PECs) were prepared from Chitosan (CS) and Hyaluronic Acid (HYA) homogeneous mixtures of aqueous solutions. The method consisted of preparing a homogeneous mixture of the two polysaccharides via charge screening at high salt concentrations. Then, the mixture was dialyzed, leading to the controlled self-assembly of the two polyelectrolytes. Critical parameters like the chitosan degree of acetylation (DA) and molar mass (Mw), the residual salt concentration and the molar charge ratio r=nNH3(+) (CS)/nCOO(-) (HYA) accounted for the transition from homogeneous aqueous solutions to colloidal suspensions (r=0.1) or gel coacervates (r=0.5). The influence of the DA and Mw of CS was evaluated by visual observations, light scattering and rheological measurements. For low values of r, Small Angle X-ray Scattering (SAXS) experiments revealed that the HYA nanostructure was weakly affected by the presence of PECs. On the contrary, the structure was impacted when increasing r, revealing a heterogeneous aggregate morphology with ladder-like chain interactions. PMID:27577900

  6. Fabrication and biocompatibility of poly(l-lactic acid) and chitosan composite scaffolds with hierarchical microstructures.

    PubMed

    Lou, Tao; Wang, Xuejun; Yan, Xu; Miao, Yu; Long, Yun-Ze; Yin, Hai-Lei; Sun, Bin; Song, Guojun

    2016-07-01

    The scaffold microstructure is crucial to reconstruct tissue normal functions. In this article, poly(l-lactic acid) and chitosan fiber (PLLA/CTSF) composite scaffolds with hierarchical microstructures both in fiber and pore sizes were successfully fabricated by combining thermal induced phase separation and salt leaching techniques. The composite scaffolds consisted of a nanofibrous PLLA matrix with diameter of 50-500nm, and chitosan fibers with diameter of about 20μm were homogenously distributed in the PLLA matrix as a microsized reinforcer. The composite scaffolds also had high porosity (>94%) and hierarchical pore size, which were consisted of both micropores (50nm-10μm) and macropores (50-300μm). By tailoring the microstructure and chemical composition, the mechanical property, pH buffer and protein adsorption capacity of the composite scaffold were improved significantly compared with those of PLLA scaffold. Cell culture results also revealed that the PLLA/CTSF composite scaffolds supported MG-63 osteoblast proliferation and penetration. PMID:27127062

  7. Tissue-Engineered Small Diameter Arterial Vascular Grafts from Cell-Free Nanofiber PCL/Chitosan Scaffolds in a Sheep Model.

    PubMed

    Fukunishi, Takuma; Best, Cameron A; Sugiura, Tadahisa; Shoji, Toshihiro; Yi, Tai; Udelsman, Brooks; Ohst, Devan; Ong, Chin Siang; Zhang, Huaitao; Shinoka, Toshiharu; Breuer, Christopher K; Johnson, Jed; Hibino, Narutoshi

    2016-01-01

    Tissue engineered vascular grafts (TEVGs) have the potential to overcome the issues faced by existing small diameter prosthetic grafts by providing a biodegradable scaffold where the patient's own cells can engraft and form functional neotissue. However, applying classical approaches to create arterial TEVGs using slow degrading materials with supraphysiological mechanical properties, typically results in limited host cell infiltration, poor remodeling, stenosis, and calcification. The purpose of this study is to evaluate the feasibility of novel small diameter arterial TEVGs created using fast degrading material. A 1.0mm and 5.0mm diameter TEVGs were fabricated with electrospun polycaprolactone (PCL) and chitosan (CS) blend nanofibers. The 1.0mm TEVGs were implanted in mice (n = 3) as an unseeded infrarenal abdominal aorta interposition conduit., The 5.0mm TEVGs were implanted in sheep (n = 6) as an unseeded carotid artery (CA) interposition conduit. Mice were followed with ultrasound and sacrificed at 6 months. All 1.0mm TEVGs remained patent without evidence of thrombosis or aneurysm formation. Based on small animal outcomes, sheep were followed with ultrasound and sacrificed at 6 months for histological and mechanical analysis. There was no aneurysm formation or calcification in the TEVGs. 4 out of 6 grafts (67%) were patent. After 6 months in vivo, 9.1 ± 5.4% remained of the original scaffold. Histological analysis of patent grafts demonstrated deposition of extracellular matrix constituents including elastin and collagen production, as well as endothelialization and organized contractile smooth muscle cells, similar to that of native CA. The mechanical properties of TEVGs were comparable to native CA. There was a significant positive correlation between TEVG wall thickness and CD68+ macrophage infiltration into the scaffold (R2 = 0.95, p = 0.001). The fast degradation of CS in our novel TEVG promoted excellent cellular infiltration and neotissue formation

  8. Tissue-Engineered Small Diameter Arterial Vascular Grafts from Cell-Free Nanofiber PCL/Chitosan Scaffolds in a Sheep Model

    PubMed Central

    Fukunishi, Takuma; Best, Cameron A.; Sugiura, Tadahisa; Shoji, Toshihiro; Yi, Tai; Udelsman, Brooks; Ohst, Devan; Ong, Chin Siang; Zhang, Huaitao; Shinoka, Toshiharu; Breuer, Christopher K.; Johnson, Jed; Hibino, Narutoshi

    2016-01-01

    Tissue engineered vascular grafts (TEVGs) have the potential to overcome the issues faced by existing small diameter prosthetic grafts by providing a biodegradable scaffold where the patient’s own cells can engraft and form functional neotissue. However, applying classical approaches to create arterial TEVGs using slow degrading materials with supraphysiological mechanical properties, typically results in limited host cell infiltration, poor remodeling, stenosis, and calcification. The purpose of this study is to evaluate the feasibility of novel small diameter arterial TEVGs created using fast degrading material. A 1.0mm and 5.0mm diameter TEVGs were fabricated with electrospun polycaprolactone (PCL) and chitosan (CS) blend nanofibers. The 1.0mm TEVGs were implanted in mice (n = 3) as an unseeded infrarenal abdominal aorta interposition conduit., The 5.0mm TEVGs were implanted in sheep (n = 6) as an unseeded carotid artery (CA) interposition conduit. Mice were followed with ultrasound and sacrificed at 6 months. All 1.0mm TEVGs remained patent without evidence of thrombosis or aneurysm formation. Based on small animal outcomes, sheep were followed with ultrasound and sacrificed at 6 months for histological and mechanical analysis. There was no aneurysm formation or calcification in the TEVGs. 4 out of 6 grafts (67%) were patent. After 6 months in vivo, 9.1 ± 5.4% remained of the original scaffold. Histological analysis of patent grafts demonstrated deposition of extracellular matrix constituents including elastin and collagen production, as well as endothelialization and organized contractile smooth muscle cells, similar to that of native CA. The mechanical properties of TEVGs were comparable to native CA. There was a significant positive correlation between TEVG wall thickness and CD68+ macrophage infiltration into the scaffold (R2 = 0.95, p = 0.001). The fast degradation of CS in our novel TEVG promoted excellent cellular infiltration and neotissue formation

  9. Chitosan-hyaluronic acid polyelectrolyte complex scaffold crosslinked with genipin for immobilization and controlled release of BMP-2.

    PubMed

    Nath, Subrata Deb; Abueva, Celine; Kim, Boram; Lee, Byong Taek

    2015-01-22

    Polyelectrolyte complex (PEC) is formed when polymers with opposite charges are combined in solution. PECs are recently gaining attention as carriers for controlled release of drugs and proteins. Herein, bone morphogenetic protein-2 (BMP-2) was immobilized in a PEC of natural polymers, chitosan and hyaluronic acid. Charge-to-charge stoichiometry of the formed PEC was estimated based on turbidity of combined chitosan and hyaluronic acid solutions. Free amino groups in chitosan were crosslinked with different amounts of genipin. The degree of crosslinking, consequently its effects in vitro in terms of swelling, degradation and cytocompatibility were analyzed. Immobilization of three different amount of BMP-2 in chitosan-hyaluronic acid PEC scaffold resulted sustained release of the growth factor for more than 30 days. Immobilization efficacies varied from 61% to 76% depending on the amount of BMP-2. Finally effects in osteogenic differentiation of the PEC with BMP-2 to MC3T3-E1 cells were determined by reverse transcriptase PCR. PMID:25439881

  10. Physicochemical, antimicrobial, and cytotoxic characteristics of a chitosan film cross-linked by a naturally occurring cross-linking agent, aglycone geniposidic acid.

    PubMed

    Mi, Fwu-Long; Huang, Chin-Tsung; Liang, Hsiang-Fa; Chen, Mei-Chin; Chiu, Ya-Ling; Chen, Chun-Hung; Sung, Hsing-Wen

    2006-05-01

    The purpose of this study was to evaluate the characteristics of a chitosan film cross-linked by a naturally occurring compound, aglycone geniposidic acid (aGSA). This newly developed aGSA-cross-linked chitosan film may be used as an edible film. The chitosan film without cross-linking (fresh) and the glutaraldehyde-cross-linked chitosan film were used as controls. The characteristics of test chitosan films evaluated were their degree of cross-linking, swelling ratio, mechanical properties, water vapor permeability, antimicrobial capability, cytotoxicity, and enzymatic degradability. It was found that cross-linking of chitosan films by aGSA (at a concentration up to 0.8 mM) significantly increased its ultimate tensile strength but reduced its strain at fracture and swelling ratio. There was no significant difference in the antimicrobial capability between the cross-linked chitosan films and their fresh counterpart. However, the aGSA-cross-linked chitosan film had a lower cytotoxicity, a slower degradation rate, and a relatively lower water vapor permeability as compared to the glutaraldehyde-cross-linked film. These results suggested that the aGSA-cross-linked chitosan film may be a promising material as an edible film. PMID:16637687

  11. Mobility of Transgenic Nucleic Acids and Proteins within Grafted Rootstocks for Agricultural Improvement

    PubMed Central

    Haroldsen, Victor M.; Szczerba, Mark W.; Aktas, Hakan; Lopez-Baltazar, Javier; Odias, Mar Joseph; Chi-Ham, Cecilia L.; Labavitch, John M.; Bennett, Alan B.; Powell, Ann L. T.

    2012-01-01

    Grafting has been used in agriculture for over 2000 years. Disease resistance and environmental tolerance are highly beneficial traits that can be provided through use of grafting, although the mechanisms, in particular for resistance, have frequently been unknown. As information emerges that describes plant disease resistance mechanisms, the proteins, and nucleic acids that play a critical role in disease management can be expressed in genetically engineered (GE) plant lines. Utilizing transgrafting, the combination of a GE rootstock with a wild-type (WT) scion, or the reverse, has the potential to provide pest and pathogen resistance, impart biotic and abiotic stress tolerance, or increase plant vigor and productivity. Of central importance to these potential benefits is the question of to what extent nucleic acids and proteins are transmitted across a graft junction and whether the movement of these molecules will affect the efficacy of the transgrafting approach. Using a variety of specific examples, this review will report on the movement of organellar DNA, RNAs, and proteins across graft unions. Attention will be specifically drawn to the use of small RNAs and gene silencing within transgrafted plants, with a particular focus on pathogen resistance. The use of GE rootstocks or scions has the potential to extend the horticultural utility of grafting by combining this ancient technique with the molecular strategies of the modern era. PMID:22645583

  12. 76 FR 69659 - Methacrylic Acid-Methyl Methacrylate-Polyethylene Glycol Monomethyl Ether Methacrylate Graft...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-09

    ...This regulation establishes an exemption from the requirement of a tolerance for residues of methacrylic acid-methyl methacrylate- polyethylene glycol monomethyl ether methacrylate graft copolymer when used as an inert ingredient in a pesticide chemical formulation. Akzo Noel Surface Chemistry LLC submitted a petition to EPA under the Federal Food, Drug, and Cosmetic Act (FFDCA), requesting an......

  13. An amperometric uric acid biosensor based on chitosan-carbon nanotubes electrospun nanofiber on silver nanoparticles.

    PubMed

    Numnuam, Apon; Thavarungkul, Panote; Kanatharana, Proespichaya

    2014-06-01

    A novel amperometric uric acid biosensor was fabricated by immobilizing uricase on an electrospun nanocomposite of chitosan-carbon nanotubes nanofiber (Chi-CNTsNF) covering an electrodeposited layer of silver nanoparticles (AgNPs) on a gold electrode (uricase/Chi-CNTsNF/AgNPs/Au). The uric acid response was determined at an optimum applied potential of -0.35 V vs Ag/AgCl in a flow-injection system based on the change of the reduction current for dissolved oxygen during oxidation of uric acid by the immobilized uricase. The response was directly proportional to the uric acid concentration. Under the optimum conditions, the fabricated uric acid biosensor had a very wide linear range, 1.0-400 μmol L(-1), with a very low limit of detection of 1.0 μmol L(-1) (s/n = 3). The operational stability of the uricase/Chi-CNTsNF/AgNPs/Au biosensor (up to 205 injections) was excellent and the storage life was more than six weeks. A low Michaelis-Menten constant of 0.21 mmol L(-1) indicated that the immobilized uricase had high affinity for uric acid. The presence of potential common interfering substances, for example ascorbic acid, glucose, and lactic acid, had negligible effects on the performance of the biosensor. When used for analysis of uric acid in serum samples, the results agreed well with those obtained by use of the standard enzymatic colorimetric method (P > 0.05). PMID:24718436

  14. Polymeric micelles of amphiphilic graft copolymer of α-tocopherol succinate-g-carboxymethyl chitosan for tamoxifen delivery: Synthesis, characterization and in vivo pharmacokinetic study.

    PubMed

    Jena, Sunil K; Sangamwar, Abhay T

    2016-10-20

    Novel amphiphilic graft copolymers were prepared from low molecular weight carboxymethyl chitosan (LMW Cmc) and α-tocopherol succinate (TS) via an amidation reaction and confirmed by (1)H NMR and IR spectroscopy. These graft copolymers are self-assembled to nanosized core-shell-structural micelles in an aqueous milieu. The critical micelle concentration (CMC) decreased with an increasing substitution of TS on LMW Cmc, which ranged from 7.94×10(-8) to 1.58×10(-6)g/mL. Cmc-TS4.5 (Cmc-TS with a charged molar ratio of TS to glucosamine units of Cmc∼4.5) was shown maximum TMX loading up to 8.08±0.98%. Both blank and TMX-loaded PM's of Cmc-TS4.5 exhibit spherical shape with particle size below 200nm. An in vitro release study in simulated gastric and intestinal fluid demonstrated that TMX release from TMX-PM4.5 (TMX-PMs prepared with amphiphilic polymer Cmc-TS4.5, and the weight ratio of Cmc-TS4.5 to TMX was 8:1) was slow and pH dependent. In vivo oral absorption study revealed Cmc-TS4.5 based PM's permeated the epithelial barrier via the paracellular route without causing any intestinal damage. In vivo toxicity study demonstrated the safety of PM's after oral administration. Compared to tamoxifen control, TMX-PM4.5 dosed to fasted female Sprague Dawley rats showed a 1.9 fold increase in AUC0-72h. Thus, the results suggested that Cmc-TS micelles are a promising carrier for TMX delivery. PMID:27474667

  15. A density functional study on dielectric properties of acrylic acid grafted polypropylene

    NASA Astrophysics Data System (ADS)

    Ruuska, Henna; Arola, Eero; Kortelainen, Tommi; Rantala, Tapio T.; Kannus, Kari; Valkealahti, Seppo

    2011-04-01

    Influence of acrylic acid grafting of isotactic polypropylene on the dielectric properties of the polymer is investigated using density functional theory (DFT) calculations, both in the molecular modeling and three-dimensional (3D) bulk periodic system frameworks. In our molecular modeling calculations, polarizability volume, and polarizability volume per mass which reflects the permittivity of the polymer, as well as the HOMO-LUMO gap, one of the important measures indicating the electrical breakdown voltage strength, were examined for oligomers with various chain lengths and carboxyl mixture ratios. When a polypropylene oligomer is grafted with carboxyl groups (cf. acrylic acid), our calculations show that the increase of the polarizability volume α' of the oligomer is proportional to the increase of its mass m, while the ratio {{α^ ' } { α^ ' } m} decreases from the value of a pure polymer when increasing the mixture ratio. The decreasing ratio of {{α^ ' } {α^ ' } m} under carboxyl grafting indicates that the material permittivity might also decrease if the mass density of the material remains constant. Furthermore, our calculations show that the HOMO-LUMO gap energy decreases by only about 15% in grafting, but this decrease seems to be independent on the mixture ratio of carboxyl. This indicates that by doping polymers with additives better dielectric properties can be tailored. Finally, using the first-principles molecular DFT results for polarizability volume per mass in connection with the classical Clausius-Mossotti relation, we have estimated static permittivity for acrylic acid grafted polypropylene, assuming the structural density keeping constant under grafting. The computed permittivity values are in a qualitative agreement with the recent experiments, showing increasing tendency of the permittivity as a function of the grafting composition. In order to validate our molecular DFT based approach, we have also carried out extensive three

  16. A density functional study on dielectric properties of acrylic acid grafted polypropylene.

    PubMed

    Ruuska, Henna; Arola, Eero; Kortelainen, Tommi; Rantala, Tapio T; Kannus, Kari; Valkealahti, Seppo

    2011-04-01

    Influence of acrylic acid grafting of isotactic polypropylene on the dielectric properties of the polymer is investigated using density functional theory (DFT) calculations, both in the molecular modeling and three-dimensional (3D) bulk periodic system frameworks. In our molecular modeling calculations, polarizability volume, and polarizability volume per mass which reflects the permittivity of the polymer, as well as the HOMO-LUMO gap, one of the important measures indicating the electrical breakdown voltage strength, were examined for oligomers with various chain lengths and carboxyl mixture ratios. When a polypropylene oligomer is grafted with carboxyl groups (cf. acrylic acid), our calculations show that the increase of the polarizability volume α' of the oligomer is proportional to the increase of its mass m, while the ratio α'/m decreases from the value of a pure polymer when increasing the mixture ratio. The decreasing ratio of α'/m under carboxyl grafting indicates that the material permittivity might also decrease if the mass density of the material remains constant. Furthermore, our calculations show that the HOMO-LUMO gap energy decreases by only about 15% in grafting, but this decrease seems to be independent on the mixture ratio of carboxyl. This indicates that by doping polymers with additives better dielectric properties can be tailored. Finally, using the first-principles molecular DFT results for polarizability volume per mass in connection with the classical Clausius-Mossotti relation, we have estimated static permittivity for acrylic acid grafted polypropylene, assuming the structural density keeping constant under grafting. The computed permittivity values are in a qualitative agreement with the recent experiments, showing increasing tendency of the permittivity as a function of the grafting composition. In order to validate our molecular DFT based approach, we have also carried out extensive three-dimensional bulk periodic first

  17. Pharmacological performance of novel poly-(ionic liquid)-grafted chitosan-N-salicylidene Schiff bases and their complexes.

    PubMed

    Elshaarawy, Reda F M; Refaee, Ayaat A; El-Sawi, Emtithal A

    2016-08-01

    In our endeavor to develop a new class of pharmacological candidates with antimicrobial and anticancer efficacy, a series of biopolymeric chitosan Schiff bases bearing salicylidene ionic liquid (IL-Sal) brushes (ILCSB1-3, poly-(GlcNHAc-GlcNH2-(GlcN-Sal-IL)) was successfully synthesized by adopting efficient synthetic routes. Unfortunately, metalation trials of these biopolymeric Schiff bases afford the corresponding Ag(I)/M(II) complexes (where M=Co, Pd). These designed architectures were structurally characterized and pharmacologically evaluated for their in vitro antimicrobial, against common bacterial and fungal pathogens, and anticancer activities against human colon carcinoma (HCT-116) cell line. In conclusion functionalization of chitosan with IL-Sal brushes coupled with metalation of formed ILCSBs were synergistically enhanced its antimicrobial and antitumor properties to a great extent. Noteworthy, Ag-ILCSB2 (IC50=9.13μg/mL) was ca. 5-fold more cytotoxic against HCT-116 cell line than ILCSB2 (IC50=43.30μg/mL). PMID:27112887

  18. Enhancement of anti-inflammatory activity of glycyrrhizic acid by encapsulation in chitosan-katira gum nanoparticles.

    PubMed

    Bernela, Manju; Ahuja, Munish; Thakur, Rajesh

    2016-08-01

    Efforts were made to improve the bioavailability and efficacy of Glycyrrhizic acid, a triterpentine saponin obtained from Glycyrrhiza glabra, having several pharmacological properties, by its encapsulation in biocompatible biopolymeric nanoparticles. Polycationic chitosan and polyanionic gum katira were used to prepare nanoparticles by ionic complexation method. Glycyrrhizic acid was loaded into the nanoparticles and was then examined for change in its in vivo anti-inflammatory activity against carrageenan-induced rat hind paw inflammation. The effects of concentrations of glycyrrhizic acid, chitosan and katira gum, upon particle size and encapsulation efficiency of glycyrrhizic acid were studied with the help of response surface methodology employing 3-factor, 3-level central composite experimental design. Particle size and encapsulation efficiency of optimized nanoparticulate formulation were 175.8nm and 84.77%, respectively. Particles were observed in transmission electron microscopy to be spherical in shape and 80nm in size. FTIR analysis indicated electrostatic interactions between carboxyl groups of ammonium glycyrrhizinate and amino groups of chitosan. In vitro drug release studies indicated that glycyrrhizic acid was released from the nanoparticles following zero-order kinetics and that there was a sustained release of the drug with 90.71% of it being released over a 12h period, and that the mechanism of release of glycyrrhizic acid from the nanoparticles was a combination of diffusion and erosion of the polymer matrix. In-vivo anti inflammatory efficacy of glycyrrhizic acid clearly improved upon encapsulation in chitosan-katira gum nanoparticles, by overcoming the limited bioavailability of its other forms. PMID:27287555

  19. Optimized synthesis of glycyrrhetinic acid-modified chitosan 5-fluorouracil nanoparticles and their characteristics

    PubMed Central

    Cheng, Mingrong; Chen, Houxiang; Wang, Yong; Xu, Hongzhi; He, Bing; Han, Jiang; Zhang, Zhiping

    2014-01-01

    The nanoparticle drug delivery system, which uses natural or synthetic polymeric material as a carrier to deliver drugs to targeted tissues, has a broad prospect for clinical application for its targeting, slow-release, and biodegradable properties. Here, we used chitosan (CTS) and hepatoma cell-specific binding molecule glycyrrhetinic acid to synthesize glycyrrhetinic acid-modified chitosan (GA-CTS). The synthetic product was confirmed by infrared (IR) spectra and hydrogen-1 nuclear magnetic resonance. The GA-CTS/5-fluorouracil (5-FU) nanoparticles were synthesized by combining GA-CTS and 5-FU and conjugating 5-FU onto the GA-CTS nanomaterial. The central composite design was performed to optimize the preparation process as CTS:tripolyphosphate sodium (TPP) weight ratio =5:1, 5-FU:CTS weight ratio =1:1, TPP concentration =0.05% (w/v), and cross-link time =50 minutes. GA-CTS/5-FU nanoparticles had a mean particle size of 193.7 nm, a polydispersity index of 0.003, a zeta potential of +27.4 mV, and a drug loading of 1.56%. The GA-CTS/5-FU nanoparticle had a protective effect on the drug against plasma degrading enzyme, and provided a sustained release system comprising three distinct phases of quick, steady, and slow release. Our study showed that the peak time, half-life time, mean residence time and area under the curve of GA-CTS/5-FU were longer or more than those of the 5-FU group, but the maximum concentration (Cmax) was lower. We demonstrated that the nanoparticles accumulated in the liver and have significantly inhibited tumor growth in an orthotropic liver cancer mouse model. PMID:24493926

  20. Design and evaluation of inhalable chitosan-modified poly (DL-lactic-co-glycolic acid) nanocomposite particles.

    PubMed

    Yang, Mingshi; Yamamoto, Hiromitsu; Kurashima, Homare; Takeuchi, Hirofumi; Yokoyama, Toyokazu; Tsujimoto, Hiroyuki; Kawashima, Yoshiaki

    2012-08-30

    The aim of this study was to investigate two types of chitosan-modified poly (DL-lactic-co-glycolic acid) (PLGA) nanocomposite particles containing salmon calcitonin for pulmonary delivery, which were obtained using spray drying fluidized bed granulation (Agglomaster™) and dry powder coating techniques (Mechanofusion™), respectively. The physicochemical properties, pulmonary distribution, pulmonary clearance rate as well as in vivo hypocalcemia actions of the two types of nanocomposite particles were investigated. As indicated by scanning electron micrographs, soft matrix nanocomposite particles and soft ordered nanocomposite particles were produced by Agglomaster™ and Mechanofusion™, respectively. Both forms of chitosan-modified PLGA nanocomposite particles exhibited a high inhalation efficiency, i.e. more than 50% of the two types of nanocomposite particles could be deposited in the deep lung of male Wistar rats. However, the chitosan-modified PLGA nanocomposite particles designed by Agglomaster™ exhibited superior properties to those obtained by Mechanofusion™ with respect to the redispersibility of fine particles in aqueous liquid, the pulmonary retention time and pharmacological effects. In addition, compared with non-modified PLGA nanocomposite particles, the chitosan-modified PLGA nanocomposite particles obtained by Agglomaster™ exhibited enhanced pulmonary absorption of salmon calcitonin via the lung. The findings in this study suggest that the spray drying fluidized bed granulation technique is superior to the dry powder coating technique for producing chitosan-modified dry powder formulations containing salmon calcitonin for inhalation. This can be attributed to the avoidance of aggregation of chitosan-modified PLGA nanocomposite particles when using Agglomaster™ rather than Mechanofusion™. PMID:22683651

  1. Chitosan oligosaccharide induces resistance to Tobacco mosaic virus in Arabidopsis via the salicylic acid-mediated signalling pathway.

    PubMed

    Jia, Xiaochen; Meng, Qingshan; Zeng, Haihong; Wang, Wenxia; Yin, Heng

    2016-01-01

    Chitosan is one of the most abundant carbohydrate biopolymers in the world, and chitosan oligosaccharide (COS), which is prepared from chitosan, is a plant immunity regulator. The present study aimed to validate the effect of COS on inducing resistance to tobacco mosaic virus (TMV) in Arabidopsis and to investigate the potential defence-related signalling pathways involved. Optimal conditions for the induction of TMV resistance in Arabidopsis were COS pretreatment at 50 mg/L for 1 day prior to inoculation with TMV. Multilevel indices, including phenotype data, and TMV coat protein expression, revealed that COS induced TMV resistance in wild-type and jasmonic acid pathway- deficient (jar1) Arabidopsis plants, but not in salicylic acid pathway deficient (NahG) Arabidopsis plants. Quantitative-PCR and analysis of phytohormone levels confirmed that COS pretreatment enhanced the expression of the defence-related gene PR1, which is a marker of salicylic acid signalling pathway, and increased the amount of salicylic acid in WT and jar1, but not in NahG plants. Taken together, these results confirm that COS induces TMV resistance in Arabidopsis via activation of the salicylic acid signalling pathway. PMID:27189192

  2. Chitosan oligosaccharide induces resistance to Tobacco mosaic virus in Arabidopsis via the salicylic acid-mediated signalling pathway

    PubMed Central

    Jia, Xiaochen; Meng, Qingshan; Zeng, Haihong; Wang, Wenxia; Yin, Heng

    2016-01-01

    Chitosan is one of the most abundant carbohydrate biopolymers in the world, and chitosan oligosaccharide (COS), which is prepared from chitosan, is a plant immunity regulator. The present study aimed to validate the effect of COS on inducing resistance to tobacco mosaic virus (TMV) in Arabidopsis and to investigate the potential defence-related signalling pathways involved. Optimal conditions for the induction of TMV resistance in Arabidopsis were COS pretreatment at 50 mg/L for 1 day prior to inoculation with TMV. Multilevel indices, including phenotype data, and TMV coat protein expression, revealed that COS induced TMV resistance in wild-type and jasmonic acid pathway- deficient (jar1) Arabidopsis plants, but not in salicylic acid pathway deficient (NahG) Arabidopsis plants. Quantitative-PCR and analysis of phytohormone levels confirmed that COS pretreatment enhanced the expression of the defence-related gene PR1, which is a marker of salicylic acid signalling pathway, and increased the amount of salicylic acid in WT and jar1, but not in NahG plants. Taken together, these results confirm that COS induces TMV resistance in Arabidopsis via activation of the salicylic acid signalling pathway. PMID:27189192

  3. A new supporting material for fascia grafting during myringoplasty: polyglycolic acid sheets.

    PubMed

    Yamanaka, Toshiaki; Sawai, Yachiyo; Hosoi, Hiroshi

    2013-08-01

    We used polyglycolic acid (PGA) sheets, a reinforcing material, as supporting devices for securing the fascia instead of fibrin glue or Gelfoam in patients with tympanic membrane (TM) perforations. PGA sheets were placed lateral to the fascia graft attached using the underlay grafting technique in 6 patients. In each case, the PGA sheet had been macerated and had merged into the fascia within 1 week of the procedure. At 2 to 3 postoperative weeks, parts of the sheet had become dehydrated and detached from the fascia, revealing a new epithelialized TM underneath. Eventually, the sheet had disappeared, and complete epithelialization had been achieved at 4 to 5 postoperative weeks, resulting in the successful closure of the perforation. The repair of TM remained stable throughout the follow-up period of at least 6 months in all patients. These results suggest that PGA sheets have the potential to secure fascia grafts and to guide the epithelialization of new tissue. PMID:23744836

  4. Amylopectin grafted with poly (acrylic acid): development and application of a high performance flocculant.

    PubMed

    Sarkar, Amit Kumar; Mandre, N R; Panda, A B; Pal, Sagar

    2013-06-20

    In recent years, wastewater treatment, especially for wastewaters which are not suitably recycled by conventional or normal biological processes, is getting more importance. Of late, natural biopolymer based flocculants are extensively used for wastewater treatment because of low cost, environment-friendly and easily availablility from reproducible farm and forest resources. This article introduces the development of a natural polymer based flocculant [amylopectin grafted with poly (acrylic acid) - AP-g-PAA] for treatment of synthetic effluent as well as mining industry wastewater. The graft copolymer based flocculants have been developed under optimum conditions and characterized using viscometry, (13)C NMR, SEM, TGA, rheological characteristics, determination of hydrodynamic radius and CHN analysis. The flocculation characteristics of grafted and ungrafted polysaccharide have been evaluated in synthetic effluents (as Fe-ore, kaolin, Mn ore suspensions) as well as in mining industry wastewater. PMID:23648038

  5. Poly(acrylic acid)-grafted fluoropolymer films for highly sensitive fluorescent bioassays.

    PubMed

    Jung, Chan-Hee; Hwang, In-Tae; Kuk, In-Seol; Choi, Jae-Hak; Oh, Byung-Keun; Lee, Young-Moo

    2013-03-01

    In this study, a facile and effective method for the surface functionalization of inert fluoropolymer substrates using surface grafting was demonstrated for the preparation of a new platform for fluorescence-based bioassays. The surface of perfluorinated poly(ethylene-co-propylene) (FEP) films was functionalized using a 150 keV ion implantation, followed by the graft polymerization of acrylic acid, to generate a high density of carboxylic acid groups on the implanted surface. The resulting functionalized surface was investigated in terms of the surface density of carboxylic acid, wettability, chemical structure, surface morphology, and surface chemical composition. These results revealed that poly(acrylic acid) (PAA) was successfully grafted onto the implanted FEP surface and its relative amount depended on the fluence. To demonstrate the usefulness of this method for the fabrication of bioassays, the PAA-grafted FEP films were utilized for the immobilization of probe DNA for anthrax toxin, followed by hybridization with Cy3-labeled target DNA. Liver cancer-specific α-feto-protein (AFP) antigen was also immobilized on the PAA-grafted FEP films. Texas Red-labeled secondary antibody was reacted with AFP-specific primary antibody prebound to the AFP antigen using an immunoassay method. The results revealed that the fluorescence intensity clearly depended on the concentration of the target DNA hybridized to the probe DNA and the AFP antigen immobilized on the FEP films. The lowest detectable concentrations of the target DNA and the AFP antigen were 10 fg/mL and 10 pg/mL, respectively, with the FEP films prepared at a fluence of 3 × 10(14) ions/cm(2). PMID:23452270

  6. Preparation and Biophysical Characterization of Poly(amidoamine) Dendrimer-Poly(acrylic acid) Graft.

    PubMed

    Dung, Tran Huu; Do, Le Thanh; Loan, Ta Thi; Yoo, Hoon

    2015-01-01

    A series of PAMAM dendrimer generation 5-poly(acrylic acid) grafts were prepared to evaluate the potential use of dendritic grafts as a drug encapsulated nanocarrier. The structural features of the synthesized polymer graft were identified by FT-IR and 1H-NMR spectra and the biophysical properties were characterized by measuring its particle size and zeta potential. The prepared dendrimer G5-PAA grafts had particle size in the range of 600 to 900 nm and the size increased proportionally with the number of PAA on dendrimer surface. The electrostatic property of the dendrimer G5-PAA, carried out by HPLC reversed phase column analysis and the measurement of zeta potential, revealed that both migration time and zeta potential were dependent on the number of grafted PAA. The number of free amino groups on dendrimer G5-PAA, determined quantitatively by fluorescamine assay, was in a reverse order with the reaction mole ratio of dendrimer to PAA. In addition, dendrimer G5-PAA showed a pH-dependent solubility in aqueous solution with characteristic pH region of solubility, depending on the dendrimer generation. The observed biophysical properties indicate that PAMAM dendrimer G5-PAA is promising as a drug encapsulated nanocarrier. PMID:26328427

  7. Graft Polymerization of Acrylic Acid on a Polytetrafluoroethylene Panel by an Inductively Coupled Plasma

    NASA Astrophysics Data System (ADS)

    Lan, Yan; You, Qingliang; Cheng, Cheng; Zhang, Suzhen; Ni, Guohua; Nagatsu, M.; Meng, Yuedong

    2011-02-01

    Surface modification on a polytetrafluoroethylene (PTFE) panel was performed with sequential nitrogen plasma treatments and surface-initiated polymerization. By introducing COO- groups to the surface of the PTFE panel through grafting polymerization of acrylic acid (AA), a transparent poly (acrylic acid) (PAA) membrane was achieved from acrylic acid solution. Grafting polymerization initiating from the active groups was achieved on the PTFE panel surface after the nitrogen plasma treatment. Utilizing the acrylic acid as monomers, with COO- groups as cross link sites to form reticulation structure, a transparent poly (acrylic acid) membrane with arborescent macromolecular structure was formed on the PTFE panel surface. Analysis methods, such as fourier transform infrared spectroscopy (FTIR), microscopy and X-ray photoelectron spectroscopy (XPS), were utilized to characterize the structures of the macromolecule membrane on the PTFE panel surface. A contact angle measurement was performed to characterize the modified PTFE panels. The surface hydrophilicities of modified PTFE panels were significantly enhanced after the plasma treatment. It was shown that the grafting rate is related to the treating time and the power of plasma.

  8. Chitosan-tethered poly(acrylonitrile-co-maleic acid) hollow fiber membrane for lipase immobilization.

    PubMed

    Ye, Peng; Xu, Zhi-Kang; Che, Ai-Fu; Wu, Jian; Seta, Patrick

    2005-11-01

    A protocol was used to prepare a dual-layer biomimetic membrane as support for enzyme immobilization by tethering chitosan on the surface of poly(acrylonitrile-co-maleic acid) (PANCMA) ultrafiltration hollow fiber membrane in the presence of 1-ethyl-3-(dimethylaminopropyl) carbodiimide hydrochloride (EDC)/N-hydroxylsuccin-imide (NHS). The chemical change of the chitosan-modified PANCMA membrane surface was confirmed with Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Lipase from Candida rugosa was immobilized on this dual-layer biomimetic membrane using glutaraldehyde (GA), and on the nascent PANCMA membrane using EDC/NHS as coupling agent. The properties of the immobilized enzymes were assayed and compared with those of the free one. It was found that both the activity retention of the immobilized lipase and the amount of bound protein on the dual-layer biomimetic membrane (44.5% and 66.5 mg/m2) were higher than those on the nascent PANCMA membrane (33.9% and 53.7 mg/m2). The kinetic parameters of the free and immobilized lipases, Km and Vmax, were also assayed. The Km values were similar for the immobilized lipases, while the Vmax value of the immobilized lipase on the dual-layer biomimetic membrane was higher than that on the nascent PANCMA membrane. Results indicated that the pH and thermal stabilities of lipase increased upon immobilization. The residual activity of the immobilized lipase after 10 uses was 53% on the dual-layer biomimetic membrane and 62% on the nascent PANCMA membrane. PMID:15919112

  9. Development of chitosan nanoparticles coated with hyaluronic acid for topical ocular delivery of dexamethasone.

    PubMed

    Kalam, Mohd Abul

    2016-08-01

    The present study involved design of dexamethasone-sodium phosphate (DEX) loaded mucoadhesive chitosan nanoparticles for topical ocular delivery to improve its precorneal retention and corneal permeability. The chitosan-sodium tripolyphosphate nanoparticle (CS-NPs) was developed through ionotropic-gelation technique. The developed CS-NPs were coated with hyaluronic-acid (HA) to make discrete, free-flowing NPs and to improve their mucoadhesive characteristics. The particle-size, zeta-potential and polydispersity-index were determined by Malvern-Zetasizer. The average size of the CS-NPs ranged from 305.25±14.29nm (without HA-coating and before freeze-drying) to 400.57±15.23nm (HA-coated and after freeze-drying). Due to the polyanionic nature of HA, reversing of zeta-potentials from +32.55±4.15 to -33.74±3.45 was observed. Polydispersity-indices varied from 0.178±0.067 (before freeze-drying of HA-coated F2) to 0.427±0.028 (after freeze-drying of HA-coated F2). The encapsulation and loading capacity of around 72.95% and 14.51% respectively were found in optimized CS-NPs. In simulated tear fluid 75.84% cumulative amount of released drug was detected and the in-vitro release results suggested the mechanism of drug release was Fickian-diffusion type. The clarity, pH, refractive index, surface tension and viscosity of the suspensions of DEX-CS-NPs were found promising for ocular use. Stability study on nanoparticles revealed no significant changes were observed in particle-size, encapsulation, drug release and physicochemical characteristics at 25°C for 3-months storage. PMID:27126165

  10. Carboxymethyl chitosan-poly(amidoamine) dendrimer core-shell nanoparticles for intracellular lysozyme delivery.

    PubMed

    Zhang, Xiaoyang; Zhao, Jun; Wen, Yan; Zhu, Chuanshun; Yang, Jun; Yao, Fanglian

    2013-11-01

    Intracellular delivery of native, active proteins is challenging due to the fragility of most proteins. Herein, a novel polymer/protein polyion complex (PIC) nanoparticle with core-shell structure was prepared. Carboxymethyl chitosan-grafted-terminal carboxyl group-poly(amidoamine) (CM-chitosan-PAMAM) dendrimers were synthesized by amidation and saponification reactions. (1)H NMR was used to characterize CM-chitosan-PAMAM dendrimers. The TEM images and results of lysozyme loading efficiency indicated that CM-chitosan-PAMAM dendrimers could self-assemble into core-shell nanoparticles, and lysozyme was efficiently encapsulated inside the core of CM-chitosan-PAMAM dendrimer nanoparticles. Activity of lysozyme was completely inhibited by CM-chitosan-PAMAM Dendrimers at physiological pH, whereas it was released into the medium and exhibited a significant enzymatic activity in an acidic intracellular environment. Moreover, the CM-chitosan-PAMAM dendrimer nanoparticles did not exhibit significant cytotoxicity in the range of concentrations below 3.16 mg/ml. The results indicated that these CM-chitosan-PAMAM dendrimers have excellent properties as highly potent and non-toxic intracellular protein carriers, which would create opportunities for novel applications in protein delivery. PMID:24053810

  11. Functional chitosan-stabilized nanoscale zero-valent iron used to remove acid fuchsine with the assistance of ultrasound.

    PubMed

    Jin, Xiaoying; Zhuang, Zechao; Yu, Bing; Chen, Zhengxian; Chen, Zuliang

    2016-01-20

    Chitosan-stabilized nanoscale zero-valent iron (CS-nZVI) was prepared and used for the removal of acid fuchsine (AF) from aqueous solution with the assistance of ultrasound. More than 98.9% of AF was removed using CS-nZVI, aged CS-nZVI (exposed to air for 2 months), while only 14.6% removal efficiency was achieved after 15 min by chitosan alone with the assistance of ultrasound. Scanning electron microscopy (SEM) confirmed that chitosan polymers were arranged in a homocentric layered structure. Thus, the polymer can prevent the aggregation of nZVI and increase their anti-oxidation capacity. X-ray diffraction (XRD) also suggested that the chitosan used in synthesis may protect nZVI nanoparticles from air oxidation. Different factors impacting on the removal of AF using CS-nZVI showed that the reduction increased when dosage and temperature increased, but decreased when pH and initial concentration rose. Kinetic studies revealed that the removal of AF fitted well to the pseudo-first-order model. The apparent activation energy was 55.34 kJ/mol, indicating a chemically controlled reaction. Finally, the application of CS-nZVI in dyeing wastewater led to a removal efficiency of 99% of AF, while the reuse test confirmed that AF's removal efficiency declined from 99.6 to 39.3% after seven cycles. PMID:26572450

  12. Radiation-induced graft polymerization of maleic acid and maleic anhydride onto ultra-fine powdered styrene butadiene rubber (UFSBR)

    NASA Astrophysics Data System (ADS)

    Peng, Jing; Xia, Haibing; Zhai, Maolin; Li, Jiuqiang; Qiao, Jinliang; Wei, Genshuan

    2007-11-01

    The functionalization of ultra-fine powdered styrene-butadiene rubber (UFSBR) was carried out using gamma radiation-induced graft polymerization of maleic acid (MA) and maleic anhydride (MAH), respectively. It was found that the graft yield of MA onto UFSBR increased rapidly up to the peak and then decreased with increasing MA content. Moreover, the peak shifted to the direction of lower MA content with increasing absorbed dose. Similarly, there was the peak of graft yield with increasing MAH content for grafting of MAH onto UFSBR, whereas the peak of graft yield was achieved at 10 wt% MAH content at different absorbed doses. On the other hand, increasing absorbed dose and decreasing monomer contents are useful to improve the graft efficiency of MA and MAH. At high dose and low monomer content, the graft yield of MAH onto UFSBR is higher than that of MA. FTIR spectra confirmed that both MA and MAH can be grafted successfully onto the UFSBR under gamma irradiation, respectively. Comparing with maleation of rubber by melt grafting, the graft yield of MAH on UFSBR is higher, which can be attributed to the network structure and nanometer size of UFSBR as well as high energy provided by radiation.

  13. SYNTHESIS AND CHARACTERIZATION OF POLYSIALIC ACID/CARBOXYMETHYL CHITOSAN HYDROGEL WITH POTENTIAL FOR DRUG DELIVERY.

    PubMed

    Wu, J R; Zhan, X B; Zheng, Z Y; Zhang, H T

    2015-01-01

    A novel hydrogel was prepared from polysialic acid (PSA) and carboxymethyl chitosan (CMCS) using glutaraldehyde as the cross-linking agent. The resulting PSA-CMCS hydrogel exhibited pH sensitivity, in which the swelling ratio under acidic conditions was higher than those under neutral or alkaline conditions. The swelling ratio of PSA-CMCS hydrogel at equilibrium depended on the medium pH, the cross-linking agent concentration, and the ratio of PSA to CMCS (w/w). Bovine serum albumin (BSA) and 5-fluorouracil (5-FU) were used as model drugs to prepare hydrogel delivery systems. The loading efficiencies of the hydrogel for BSA and 5-FU were 26.25 and 36.74%, respectively. Release behaviors of BSA and 5-FU were influenced by the pH. MTT assays confirmed that PSA-CMCS hydrogel has no cytotoxicity toward the NIH-3T3 cell line; in fact, the 100% aqueous extract of the PSA-CMCS hydrogel enhanced cell growth. These results suggest that PSA-CMCS hydrogel may be a promising pH-sensitive delivery system, especially for hydrophobic chemicals. PMID:26762102

  14. Release behavior of tetracycline hydrochloride loaded chitosan/poly(lactic acid) antimicrobial nanofibrous membranes.

    PubMed

    Jiang, Suwei; Lv, Jian; Ding, Man; Li, Yanan; Wang, Hualin; Jiang, Shaotong

    2016-02-01

    The present work aimed to evaluate the release behavior of tetracycline hydrochloride loaded chitosan/poly(lactic acid) (Tet-CS/PLA) antimicrobial nanofibrous membranes fabricated via electrospinning technique. The electrospinning solution was a blend of Tet, CS formic acid solution and PLA chloroform/ethanol solution. The interaction between CS and PLA in CS/PLA nanofibers was confirmed to be hydrogen bond. The incorporation of Tet caused a slight decrease in the diameter of nanofibers with Tet content below 30%. Tet-CS/PLA nanofibrous membrane showed a slight initial burst within the first 4h before a gradual increase in cumulative release, and the release percentage increased with increasing Tet contents. Tet release (Mt/M∞<0.6) from the medicated nanofibers could be described by Fickian diffusion model and the release profiles showed two sequential stages. Tet-CS/PLA nanofibrous membranes exhibited an effective and sustainable inhabitance on the growth of Staphylococcus aureus, and the antimicrobial activity increased rapidly with increasing Tet contents below 20%. Furthermore, the incorporation of Tet promoted the degradation of nanofibrous membranes. PMID:26652352

  15. Nanoporous multilayer poly(L-glutamic acid)/chitosan microcapsules for drug delivery.

    PubMed

    Yan, Shifeng; Rao, Shuiqin; Zhu, Jie; Wang, Zhichun; Zhang, Ying; Duan, Yourong; Chen, Xuesi; Yin, Jingbo

    2012-05-10

    Nanoporous poly(L-glutamic acid)/chitosan (PLGA/CS) multilayer microcapsules were fabricated by layer-by-layer (LbL) assembly using the porous silica particles as sacrificial templates. The LbL assembled nanoporous PLGA/CS microcapsules were characterized by Zeta-potential analyzer, FTIR, TGA, SEM, TEM and CLSM. 5-Fluorouracil (5-FU) was chosen as model drug. The drug loading content of PLGA/CS microcapsules depends on loading time, loading temperature, pH value and NaCl concentration. High loading capacity of microcapsules can be achieved by simply adjusting pH value and salt concentration. Moreover, 5-Fu loaded microcapsules take on a sustained release behavior, especially in an acid solution, in contrast to burst release of bare 5-Fu. The kinetics of 5-Fu release from PLGA/CS microcapsules conforms to Korsmeyer-Peppas and Baker-Lonsdale models, the mechanism of which can be ascribed to priority of drug diffusion and subordination of polymer degradation. The MTT cytotoxicity assay in vitro reveals the satisfactory anticancer activity of the drug-loaded PLGA/CS microcapsules. Therefore, the novel nanoporous PLGA/CS microcapsules is expected to find application in drug delivery systems. PMID:22301425

  16. Nanoencapsulation of Red Ginseng Extracts Using Chitosan with Polyglutamic Acid or Fucoidan for Improving Antithrombotic Activities.

    PubMed

    Kim, Eun Suh; Lee, Ji-Soo; Lee, Hyeon Gyu

    2016-06-15

    The potential of nanoencapsulation using bioactive coating materials for improving antithrombotic activities of red ginseng extract (RG) was examined. RG-loaded chitosan (CS) nanoparticles were prepared using antithrombotic materials, polyglutamic acid (PGA) or fucoidan (Fu). Both CS-PGA (P-NPs, 360 ± 67 nm) and CS-Fu nanoparticles (F-NPs, 440 ± 44 nm) showed sustained ginsenoside release in an acidic environment and improved ginsenoside solubility by approximately 122.8%. Both in vitro rabbit and ex vivo rat platelet aggregation of RG (22.3 and 41.5%) were significantly (p < 0.05) decreased within P-NPs (14.4 and 30.0%) and F-NPs (12.3 and 30.3%), respectively. Although RG exhibited no effect on in vivo carrageenan-induced mouse tail thrombosis, P-NPs and F-NPs demonstrated significant effects, likely the anticoagulation activity of PGA and Fu. Moreover, in the in vivo rat arteriovenous shunt model, P-NPs (156 ± 6.8 mg) and F-NPs (160 ± 3.2 mg) groups showed significantly lower thrombus formation than that of RG (190 ± 5.5 mg). Therefore, nanoencapsulation using CS, PGA, and Fu is a potential for improving the antithrombotic activity of RG. PMID:27181678

  17. ABS polymer electroless plating through a one-step poly(acrylic acid) covalent grafting.

    PubMed

    Garcia, Alexandre; Berthelot, Thomas; Viel, Pascal; Mesnage, Alice; Jégou, Pascale; Nekelson, Fabien; Roussel, Sébastien; Palacin, Serge

    2010-04-01

    A new, efficient, palladium- and chromium-free process for the electroless plating of acrylonitrile-butadiene-styrene (ABS) polymers has been developed. The process is based on the ion-exchange properties of poly(acrylic acid) (PAA) chemically grafted onto ABS via a simple and one-step method that prevents using classical surface conditioning. Hence, ABS electroless plating can be obtained in three steps, namely: (i) the grafting of PAA onto ABS, (ii) the copper Cu(0) seeding of the ABS surface, and (iii) the nickel or copper metallization using commercial-like electroless plating bath. IR, XPS, and SEM were used to characterize each step of the process, and the Cu loading was quantified by atomic absorption spectroscopy. This process successfully compares with the commercial one based on chromic acid etching and palladium-based seed layer, because the final metallic layer showed excellent adhesion with the ABS substrate. PMID:20361751

  18. A spermine conjugated stearic acid-g-chitosan oligosaccharide polymer with different types of amino groups for efficient p53 gene therapy.

    PubMed

    Meng, Tingting; Wu, Jie; Yi, Hanxi; Liu, Jingwen; Lu, Binbin; Yuan, Ming; Huang, Xuan; Yuan, Hong; Hu, Fuqiang

    2016-09-01

    The effect of various amino groups on gene vector is different. In order to combine their effect in one vector and finally promote the transfection efficiency, a biogenic tetra-amine spermine was introduced to modify the stearic acid-grafted chitosan oligosaccharide (CSOSA) polymer to build a new gene delivery system. The spermine linked CSOSA (SP-CSOSA) polymer consists two types of amino groups with 73.3%, 19.3% of all nitrogen atoms for primary and secondary amine groups, respectively. The SP modified CSOSA showed strong DNA condensation capability and obviously enhanced proton binding ability especially at about pH 5.0, which significantly promoted the escape of SP-CSOSA/pDNA complexes from endo-lysosoms. Moreover, the transfection efficiency at the N/P ratio of 10 could compete with that of Lipofectamine 2000 and PEI 25K, but with lower cytotoxicities. The therapeutic wild type p53 gene transfected by the SP-CSOSA polymer restored the function of aberrant p53 gene and induced obvious cell apoptosis and G1 phase arrest. We concluded that the new vector SP-CSOSA polymer proved to be a potential delivery system for gene therapy. PMID:27289311

  19. Depolymerization of crystalline cellulose catalyzed by acidic ionic liquids grafted onto sponge-like nanoporous polymers.

    PubMed

    Liu, Fujian; Kamat, Ranjan K; Noshadi, Iman; Peck, Daniel; Parnas, Richard S; Zheng, Anmin; Qi, Chenze; Lin, Yao

    2013-10-01

    The acidic ionic liquid (IL) functionalized polymer (PDVB-SO3H-[C3vim][SO3CF3]) possesses abundant nanoporous structures, strong acid strength and unique capability for deconstruction of crystalline cellulose into sugars in ILs. The polymer shows much improved catalytic activities in comparison with mineral acids, homogeneous acidic ionic liquids and the acidic resins such as Amberlyst 15. The enhanced catalytic activity found in the polymer is attributed to synergistic effects between the strongly acidic group and the ILs grafted onto the polymer, which by itself is capable of breaking down the crystalline structures of cellulose. This study may help develop cost-effective and green routes for conversion of biomass to fuels. PMID:23958800

  20. Design and evaluation of an intravesical delivery system for superficial bladder cancer: preparation of gemcitabine HCl-loaded chitosan-thioglycolic acid nanoparticles and comparison of chitosan/poloxamer gels as carriers.

    PubMed

    Şenyiğit, Zeynep Ay; Karavana, Sinem Yaprak; İlem-Özdemir, Derya; Çalışkan, Çağrı; Waldner, Claudia; Şen, Sait; Bernkop-Schnürch, Andreas; Baloğlu, Esra

    2015-01-01

    This study aimed to develop an intravesical delivery system of gemcitabine HCl for superficial bladder cancer in order to provide a controlled release profile, to prolong the residence time, and to avoid drug elimination via urination. For this aim, bioadhesive nanoparticles were prepared with thiolated chitosan (chitosan-thioglycolic acid conjugate) and were dispersed in bioadhesive chitosan gel or in an in situ gelling poloxamer formulation in order to improve intravesical residence time. In addition, nanoparticle-loaded gels were diluted with artificial urine to mimic in vivo conditions in the bladder and were characterized regarding changes in gel structure. The obtained results showed that chitosanthioglycolic acid nanoparticles with a mean diameter of 174.5±3.762 nm and zeta potential of 32.100±0.575 mV were successfully developed via ionotropic gelation and that the encapsulation efficiency of gemcitabine HCl was nearly 20%. In vitro/ex vivo characterization studies demonstrated that both nanoparticles and nanoparticle-loaded chitosan and poloxamer gels might be alternative carriers for intravesical administration of gemcitabine HCl, prolonging its residence time in the bladder and hence improving treatment efficacy. However, when the gel formulations were diluted with artificial urine, poloxamer gels lost their in situ gelling properties at body temperature, which is in conflict with the aimed formulation property. Therefore, 2% chitosan gel formulation was found to be a more promising carrier system for intravesical administration of nanoparticles. PMID:26508855

  1. Chitosan grafted methoxy poly(ethylene glycol)-poly(ε-caprolactone) nanosuspension for ocular delivery of hydrophobic diclofenac

    PubMed Central

    Shi, Shuai; Zhang, Zhaoliang; Luo, Zichao; Yu, Jing; Liang, Renlong; Li, Xingyi; Chen, Hao

    2015-01-01

    This study aimed to develop a cationic nanosuspension of chitosan (CS) and methoxy poly(ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL) for ocular delivery of diclofenac (DIC). MPEG-PCL-CS block polymer was synthesized by covalent coupling of MPEG-PCL with CS. The critical micelle concentration of the MPEG-PCL-CS block polymer was 0.000692 g/L. DIC/MPEG-PCL-CS nanosuspension (mean particle size = 105 nm, zeta potential = 8 mV) was prepared and characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and differential scanning calorimetry. The nanosuspension was very stable without apparent physical property changes after storage at 4 °C or 25 °C for 20 days, but it was unstable in the aqueous humor solution after 24 h incubation. Sustained release of the encapsulated DIC from the nanosuspension occurred over 8 h. Neither a blank MPEG-PCL-CS nanosuspension nor a 0.1% (mass fraction) DIC/MPEG-PCL-CS nanosuspension caused ocular irritation after 24 h of instillation. Enhanced penetration and retention in corneal tissue was achieved with a Nile red/MPEG-PCL-CS nanosuspension compared with a Nile red aqueous solution. In vivo pharmacokinetics studies showed enhanced pre-corneal retention and penetration of the DIC/MPEG-PCL-CS nanosuspension, which resulted in a higher concentration of DIC (Cmax) in the aqueous humor and better bioavailability compared with commercial DIC eye drops (P < 0.01). PMID:26067670

  2. Potassium fulvate as co-interpenetrating agent during graft polymerization of acrylic acid from cellulose.

    PubMed

    Ghazy, Mohamed B M; El-Hai, Farag Abd; Mohamed, Magdy F; Essawy, Hisham A

    2016-10-01

    Grafting polymerization of acrylic acid onto cellulose in presence of potassium fulvate (KF) as a co-interpenetrating agent results enhanced water sorption compared to materials prepared similarly in its absence. The insertion of potassium fulvate (KF) did not affect the grafting process and is thought to proceed in parallel to the graft polymerization via intensive polycondensation reactions of its function groups (-COOH and OH) with COOH of the monomer and OH groups of cellulose. The combination of graft copolymerization and polycondensation reactions is assumed to produce interpenetrating network structure. Fourier transform infrared (FTIR) confirmed successful incorporation within the network structure which is an evidence for formation of interpenetrating network. The obtained structures showed homogeneous uniform surface as revealed by scanning electron microscopy (SEM). The obtained superabsorbent possessed high water absorbency 422 and 48.8g/g in distilled water and saline (0.9wt.% NaCl solution), respectively, and enhanced water retention even at elevated temperatures as revealed by thermogravimetric analysis (TGA). This could be explained by the high content of hydrophilic groups. The new superabsorbents proved to be efficient devices for controlled release of fertilizers which expands their use in agricultural applications. PMID:27370745

  3. Acidic ionic liquid catalyzed crosslinking of oxycellulose with chitosan for advanced biocomposites.

    PubMed

    Zhou, Yonghui; Fan, Mizi; Luo, Xiaolin; Huang, Liulian; Chen, Lihui

    2014-11-26

    This paper presents a novel environmentally friendly production of chitosan-crosslinked oxycellulose films by using ionic liquids (AmimCl and SmimHSO4). The effect of reaction parameters on chitosan contents and mechanical properties of chitosan-crosslinked oxycellulose films was also investigated. The results revealed that appropriate SmimHSO4 dosage and reaction time were 5% and 2h respectively. FTIR analysis of chitosan-crosslinked oxycellulose film suggested that the chitosan was crosslinked with oxycellulose through the reaction between the amino groups in chitosan and the aldehyde groups in oxycellulose, and the results of XPS analysis further confirmed the reaction between both polysaccharides. SEM images suggested that the developed chitosan-crosslinked oxycellulose films had a smooth and compact structure, and a highly inhibitory effect against the bacteria of Escherichia coli and Staphylococcus aureus. The developed materials and technologies could be further formulated for the production of various antimicrobial and biomedical products or water treatment membranes. PMID:25256465

  4. Differentiation Potential of Mesenchymal Stem Cells from Equine Bone Marrow Cultured on Hyaluronic Acid-Chitosan Polyelectrolyte Multilayer Biofilm.

    PubMed

    Listoni, Amanda J; Arruda, Isadora; Maia, Leandro; Barberini, Danielle J; Martins, Ian; Vasconcellos, Fernando C; Landim-Alvarenga, Fernanda C

    2015-01-01

    Nanotechnology techniques have a prominent role in the current technical and scientific scene. The layer-by-layer (LbL) deposition allows obtaining nanostructures with sophisticated multilayer, using a simple, but versatile technique. This procedure, which is used to coat and functionalize surfaces with nanometer- thick films, has applications in bioengineering, medicine, chemistry, materials and chemical engineering among other areas. Chitosan is a biomaterial, coming from the chitin, a very abundant polymer in nature, which has been recently tested as scaffolds. In this experiment we test the hypothesis that the hyaluronic acid-chitosan polyelectrolyte multilayer biofilm would be a good substrate to the adherence of equine mesenchymal stem cells derived from bone marrow. The results showed that these biofilms accelerate the process of cell adhesion on smooth surfaces, allowing a constant cell growth and creating a great option to cover surgical materials. PMID:27125135

  5. Controlled release of tyrosol and ferulic acid encapsulated in chitosan-gelatin films after electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Benbettaïeb, Nasreddine; Assifaoui, Ali; Karbowiak, Thomas; Debeaufort, Frédéric; Chambin, Odile

    2016-01-01

    This work deals with the study of the release kinetics of antioxidants (ferulic acid and tyrosol) incorporated into chitosan-gelatin edible films after irradiation processes. The aim was to determine the influence of electron beam irradiation (at 60 kGy) on the retention of antioxidants in the film, their release in water (pH=7) at 25 °C, in relation with the barrier and mechanical properties of biopolymer films. The film preparation process coupled to the irradiation induced a loss of about 20% of tyrosol but did not affect the ferulic acid content. However, 27% of the ferulic acid remained entrapped in the biopolymer network during the release experiments whereas all tyrosol was released. Irradiation induced a reduction of the release rate for both compounds, revealing that cross-linking occurred during irradiation. This was confirmed by the mechanical properties enhancement which tensile strength value significantly increased and by the reduction of permeabilities. Although molecular weights, molar volume and molecular radius of the two compounds are very similar, the effective diffusivity of tyrosol was 40 times greater than that of ferulic acid. The much lower effective diffusion coefficient of ferulic acid as determined from the release kinetics was explained by the interactions settled between ferulic acid molecules and the gelatin-chitosan matrix. As expected, the electron beam irradiation allowed modulating the retention and then the release of antioxidants encapsulated.

  6. Carboxymethyl chitosan-mediated synthesis of hyaluronic acid-targeted graphene oxide for cancer drug delivery.

    PubMed

    Yang, Huihui; Bremner, David H; Tao, Lei; Li, Heyu; Hu, Juan; Zhu, Limin

    2016-01-01

    In order to enhance the efficiency and specificity of anticancer drug delivery and realize intelligently controlled release, a new drug carrier was developed. Graphene oxide (GO) was first modified with carboxymethyl chitosan (CMC), followed by conjugation of hyaluronic acid (HA) and fluorescein isothiocyanate (FI). The resulting GO-CMC-FI-HA conjugate was characterized and used as a carrier to encapsulate the anticancer drug doxorubicin (DOX) to study in vitro release behavior. The drug loading capacity is as high as 95% and the drug release rate under tumor cell microenvironment of pH 5.8 is significantly higher than that under physiological conditions of pH 7.4. Cell uptake studies show that the GO-CMC-FI-HA/DOX complex can specifically target cancer cells, which are over-expressing CD44 receptors and effectively inhibit their growth. The above results suggest that the functionalized graphene-based material has potential applications for targeted delivery and controlled release of anticancer drugs. PMID:26453853

  7. Self-assembled nanoparticles based on amphiphilic chitosan derivative and hyaluronic acid for gene delivery.

    PubMed

    Liu, Ya; Kong, Ming; Cheng, Xiao Jie; Wang, Qian Qian; Jiang, Li Ming; Chen, Xi Guang

    2013-04-15

    The present work described nanoparticles (NPs) made of oleoyl-carboxymethy-chitosan (OCMCS)/hyaluronic acid (HA) using coacervation process as novel potential carriers for gene delivery. An N/P ratio of 5 and OCMCS/HA weight ratio of 4 were the optimal conditions leading to the smallest (164.94 nm), positive charged (+14.2 mV) and monodispersed NPs. OCMCS-HA/DNA (OHD) NPs showed higher in vitro DNA release rates and increased cellular uptake by Caco-2 cells due to the HA involved in NPs. The MTT survival assay indicated no significant cytotoxicity. The transfection efficiency of OHD NPs was 5-fold higher than OCMCS/DNA (OD) NPs; however, it decreased significantly in the presence of excess free HA. The results indicated that OHD NPs internalized in Caco-2 cells were mediated by the hyaluronan receptor CD44. The data obtained in the present research gave evidence of the potential of OHD NPs for the targeting and further transfer of genes to the epithelial cells. PMID:23544543

  8. Poly(lactic-co-glycolic) Acid-Chitosan Dual Loaded Nanoparticles for Antiretroviral Nanoformulations.

    PubMed

    Makita-Chingombe, Faithful; Kutscher, Hilliard L; DiTursi, Sara L; Morse, Gene D; Maponga, Charles C

    2016-01-01

    Poly(lactic-co-glycolic acid) (PLGA) chitosan (CS) coated nanoparticles (NPs) were loaded with two antiretrovirals (ARVs) either lamivudine (LMV) which is hydrophilic or nevirapine (NVP) which is hydrophobic or both LMV and NVP. These ARVs are of importance in resource-limited settings, where they are commonly used in human immunodeficiency virus (HIV-1) treatment due to affordability and accessibility. NPs prepared by a water-oil-water emulsion and reduced pressure solvent evaporation technique were determined to have a positive zeta potential, a capsule-like morphology, and an average hydrodynamic diameter of 240 nm. Entrapment of NVP as a single ARV had a notable increase in NP size compared to LMV alone or in combination with LMV. NPs stored at room temperature in distilled water maintained size, polydispersity (PDI), and zeta potential for one year. No changes in size, PDI, and zeta potential were observed for NPs in 10% sucrose in lyophilized or nonlyophilized states stored at 4°C and -20°C, respectively. Freezing NPs in the absence of sucrose increased NP size. Drug loading, encapsulation efficiency, and kinetic release profiles were quantified by high performance liquid chromatography (HPLC). Our novel nanoformulations have the potential to improve patient outcomes and expand drug access in resource-limited countries for the treatment of HIV-1. PMID:27190651

  9. Self-healing multilayer polyelectrolyte composite film with chitosan and poly(acrylic acid).

    PubMed

    Zhu, Yanxi; Xuan, Hongyun; Ren, Jiaoyu; Ge, Liqin

    2015-11-21

    If self-healing materials can be prepared via simple technology and methods using nontoxic materials, this would be a great step forward in the creation of environmentally friendly self-healing materials. In this paper, the specific structural parameters of the various hydrogen bonds between chitosan (CS) and polyacrylic acid (PAA) were calculated. Then, multilayer polyelectrolyte films were fabricated with CS and PAA based on layer-by-layer (LbL) self-assembly technology at different pH values. The possible influence of pH on the (CS/PAA) × 30 multilayer polyelectrolyte film was investigated. The results show that the interactions between CS and PAA, swelling capacity, microstructure, wettability, and self-healing ability are all governed by the pH of the CS solution. When the pH value of the CS solution is 3.0, the prepared multilayer polyelectrolyte film (CS3.0/PAA2.8) × 30 has fine-tuned interactions, a network-like structure, good swelling ability, good hydrophilicity, and excellent self-healing ability. This promises to greatly widen the future applications of environmentally friendly materials and bio-materials. PMID:26364567

  10. In vitro biocompatibility of chitosan/hyaluronic acid-containing calcium phosphate bone cements.

    PubMed

    Hesaraki, Saeed; Nezafati, Nader

    2014-08-01

    The need for bone repair has increased as the population ages. In this research, calcium phosphate cements, with and without chitosan (CS) and hyaluronic acid (HA), were synthesized. The composition and morphological properties of cements were evaluated by X-ray diffraction and scanning electron microscopy. The acellular in vitro bioactivity revealed that different apatite morphologies were formed on the surfaces of cements after soaking in simulated body fluid. The in vitro osteoblastic cell biocompatibility of in situ forming cements was evaluated and compared with those of conventional calcium phosphate cements (CPCs). The viability and growth rate of the cells were similar for all CPCs, but better alkaline phosphatase activity was observed for CPC with CS and HA. Calcium phosphate cements supported attachment of osteoblastic cells on their surfaces. Spindle-shaped osteoblasts with developed cytoplasmic membrane were found on the surfaces of cement samples after 7 days of culture. These results reveal the potential of the CPC-CS/HA composites to be used in bone tissue engineering. PMID:24399509

  11. Ursolic acid-loaded chitosan nanoparticles induce potent anti-angiogenesis in tumor.

    PubMed

    Jin, Hua; Pi, Jiang; Yang, Fen; Wu, Chaomin; Cheng, Xueli; Bai, Haihua; Huang, Dan; Jiang, Jinhuan; Cai, Jiye; Chen, Zheng W

    2016-08-01

    Angiogenesis provides necessary nutrients and oxygen for tumor growth and metastasis; thus, every stage of angiogenesis process is the potential target for cancer therapies. Ursolic acid (UA) is reported to decrease tumor burden through anti-angiogenesis pathway, but its poor water solubility greatly limits its efficiency and clinical application. Here, a simple method for preparing UA-loaded chitosan nanoparticles (CH-UA-NPs) with anti-angiogenesis and anti-tumor activity was demonstrated. In vitro, CH-UA-NPs could significantly inhibit the proliferation, migration, and tube formation of human umbilical vascular endothelial cells (HUVECs). After uptake by HUVECs, CH-UA-NPs were mainly localized in lysosomes and mitochondria, but not nuclei. CH-UA-NPs induced the destruction of lysosome membrane integrity, collapse of mitochondrial membrane potential, and reorganization of cell cytoskeleton. All these changes led to the apoptosis or necrosis in HUVECs. In vivo, CH-UA-NPs could inhibit the angiogenesis in chicken chorioallantoic membrane (CAM) model and H22 xenograft model. Notably, comparing with free UA, such synthesized CH-UA-NPs could save about tenfold of UA doses, implying that this could significantly decrease the side effects induced by high doses of UA in biological organism. Our data showed that CH-UA-NPs and this nanoparticle-based drug delivery system could be as a potential drug candidate for anti-angiogenesis treatment. PMID:26883344

  12. Lactobionic acid and carboxymethyl chitosan functionalized graphene oxide nanocomposites as targeted anticancer drug delivery systems.

    PubMed

    Pan, Qixia; Lv, Yao; Williams, Gareth R; Tao, Lei; Yang, Huihui; Li, Heyu; Zhu, Limin

    2016-10-20

    In this work, we report a targeted drug delivery system built by functionalizing graphene oxide (GO) with carboxymethyl chitosan (CMC), fluorescein isothiocyanate and lactobionic acid (LA). Analogous systems without LA were prepared as controls. Doxorubicin (DOX) was loaded onto the composites through adsorption. The release behavior from both the LA-functionalized and the LA-free material is markedly pH sensitive. The modified GOs have high biocompatibility with the liver cancer cell line SMMC-7721, but can induce cell death after 24h incubation if loaded with DOX. Tests with shorter (2h) incubation times were undertaken to investigate the selectivity of the GO composites: under these conditions, neither DOX-loaded system was found to be toxic to the non-cancerous L929 cell line, but the LA-containing composite showed the ability to selectively induce cell death in cancerous (SMMC-7721) cells while the LA-free analogue was inactive here also. These findings show that the modified GO materials are strong potential candidates for targeted anticancer drug delivery systems. PMID:27474628

  13. Poly(lactic-co-glycolic) Acid-Chitosan Dual Loaded Nanoparticles for Antiretroviral Nanoformulations

    PubMed Central

    Makita-Chingombe, Faithful; Kutscher, Hilliard L.; DiTursi, Sara L.; Morse, Gene D.; Maponga, Charles C.

    2016-01-01

    Poly(lactic-co-glycolic acid) (PLGA) chitosan (CS) coated nanoparticles (NPs) were loaded with two antiretrovirals (ARVs) either lamivudine (LMV) which is hydrophilic or nevirapine (NVP) which is hydrophobic or both LMV and NVP. These ARVs are of importance in resource-limited settings, where they are commonly used in human immunodeficiency virus (HIV-1) treatment due to affordability and accessibility. NPs prepared by a water-oil-water emulsion and reduced pressure solvent evaporation technique were determined to have a positive zeta potential, a capsule-like morphology, and an average hydrodynamic diameter of 240 nm. Entrapment of NVP as a single ARV had a notable increase in NP size compared to LMV alone or in combination with LMV. NPs stored at room temperature in distilled water maintained size, polydispersity (PDI), and zeta potential for one year. No changes in size, PDI, and zeta potential were observed for NPs in 10% sucrose in lyophilized or nonlyophilized states stored at 4°C and −20°C, respectively. Freezing NPs in the absence of sucrose increased NP size. Drug loading, encapsulation efficiency, and kinetic release profiles were quantified by high performance liquid chromatography (HPLC). Our novel nanoformulations have the potential to improve patient outcomes and expand drug access in resource-limited countries for the treatment of HIV-1. PMID:27190651

  14. Effects of chitosan, gallic acid, and algicide on the physiological and biochemical properties of Microcystis flos-aquae.

    PubMed

    Guo, Peiyong; Liu, Yang; Liu, Cong

    2015-09-01

    The effects of chitosan, gallic acid, and algicide chitosan-gallate on the activities of antioxidant enzymes, malonaldehyde (MDA) content, and photosynthetic activity of Microcystis flos-aquae were investigated to explore the physiological and biochemical mechanisms of algicides. Results demonstrated that chitosan did not significantly affect catalase (CAT) and superoxide dismutase (SOD) activities, MDA content, and photosynthetic activity in this alga. At 30 mg L(-1), gallic acid, CAT, and SOD activities and MDA of M. flos-aquae cells showed maximums of 2.872 × 10(-10) mg·cell(-1) min(-1), 0.787 × 10(-8) U·cell(-1), and 0.626 × 10(-8) nmol·cell(-1), respectively. Photosynthetic organs in algal cells were severely damaged under the stress of high gallic acid concentrations, inducing blockage of photosynthetic electron transport and resulting in the inability to restore normal photosynthetic activity. CAT and SOD activities and MDA content with lower algicide concentration were significantly higher than the control group (p < 0.05) and, in higher algicide groups, significantly lower than the control (p < 0.05). Algicide releasing gallic acid in groups treated with 60, 90, and 130 mg/L algicide was strong enough to cause severe damage to photosynthetic organs in these algal cells. The algicide suppression time was longer than that of directly added gallic acid. PMID:25943506

  15. Generation of Vascular Graft Biomaterials via the Modification of Polyurethane with Hyaluronic Acid

    NASA Astrophysics Data System (ADS)

    Ruiz, Amaliris

    Cardiovascular disease is the leading cause of mortality in the United States, necessitating surgical interventions such as small diameter (I.D. <6 mm) bypass grafting. Although the use of autologous veins as small diameter grafts produces favorable results, their limited availability provides a significant obstacle. Meanwhile, several synthetic materials have demonstrated success as large-diameter vascular grafts, but exhibit poor patency and high failure rates in small-diameter applications. Based on these limitations and the clinical issues associated with them, it is clear that there is a significant need to develop new materials for cardiovascular and blood-contacting applications that could be used to fabricate small-diameter vascular grafts. Thus, in this thesis we have designed and characterized a new polymer that is composed of both synthetic and natural elements with the goal of generating a material that is appropriate for use in cardiovascular applications. Specifically, we describe the modification of polyurethane (PU), a synthetic polymer with many favorable physical characteristics, with hyaluronic acid (HA), a native glycosaminoglycan that possesses anti-thrombotic properties as well as the ability to modulate endothelial cell proliferation in a molecular weight-dependent manner. The goal of the present work was to assess in detail the impact of 1) HA molecular weight, 2) HA quantity, and 3) the method of HA incorporation (bulk vs. surface-grafted) on the vascular-specific performance of polyurethane-HA (PU-HA) materials, under static conditions and upon exposure to physiological shear stresses. The initial findings presented in this thesis indicate that these PU-HA materials possess many of the physical and biological properties that are necessary for implementation in vascular applications. These materials were able to simultaneously address the three major design criteria in vascular graft fabrication: hemocompatibility, endothelialization, and

  16. Sorption of Pb(ll) by poly(hydroxamic acid) grafted oil palm empty fruit bunch.

    PubMed

    Haron, M J; Tiansin, M; Ibrahim, N A; Kassim, A; Wan Yunus, W M Z; Talebi, S M

    2011-01-01

    This paper describes the sorption of Pb(ll) from aqueous solution. Oil palm empty fruit bunch (OPEFB) fiber was first grafted with poly(methylacrylate) and then treated with hydroxylammonium chloride in alkaline medium to produce hydroxamic acid (PHA) grafted OPEFB. Sorption of Pb(ll) by PHA-OPEFB was maximum at pH 5. The sorption followed the Langmuir model with maximum capacityof 125.0 mg g-1 at 25 degrees C. The sorption process was exothermic, as shown by the negative value of enthalpy change, Delta H0. The free energy change (DeltaG0) for the sorption was negative, showing that the sorption process was spontaneous. A kinetic study showed that the Pb(ll) sorption followed a second order kinetic model. PMID:21866782

  17. Water dispersible polytetrafluoroethylene microparticles prepared by grafting of poly(acrylic acid)

    NASA Astrophysics Data System (ADS)

    Yang, Changqiao; Xu, Lu; Zeng, Hongyan; Tang, Zhongfeng; Zhong, Lei; Wu, Guozhong

    2014-10-01

    Due to the hydrophobic nature and high gravimetric density, it is very difficult to obtain water dispersible polytetrafluoroethylene (PTFE) powder. In this work, hydrophilic PTFE microparticles were successfully prepared by grafting of poly(acrylic acid) onto PTFE micropowder via a pre-irradiation method. The as-obtained hydrophilic PTFE microparticles were analyzed by FT-IR, 1H NMR, CA, SEM and TGA. After neutralization by sodium hydroxide, the water contact angle decreased from 145.69° for pristine PTFE to 63.38° for PTFE-g-NaAA. The obtained micropowder can be easily dispersed in water to form a dispersion with very high stability. Furthermore, the presence of grafted PAA shows no obvious influence on degradation temperature of PTFE backbones.

  18. Acrylic acid grafted guargum-nanosilica membranes for transdermal diclofenac delivery.

    PubMed

    Giri, Arindam; Bhunia, Tridib; Mishra, Samir Ranjan; Goswami, Luna; Panda, Asit Baran; Pal, Sagar; Bandyopadhyay, Abhijit

    2013-01-16

    Green, hydrophobic device for controlled transdermal release of diclofenac sodium was designed from in situ nanosilica/acrylic acid grafted guargum membranes. Best grafting condition was assigned and nanocomposites were formed in situ using varying proportions of aqueous nanosilica sol. Nanocomposite/drug conjugates were formed by bringing down the medium pH from 9.0 to 7.0. The conjugates were characterized through infrared and solid state NMR spectroscopy, electron microscopy, hydro-swelling, surface contact angle, viscometry and biocompatibility. Most balanced property was exhibited by the membrane containing 1wt% nanosilica. It also had shown the highest encapsulation efficacy vis-à-vis slowest release as compared to others during experimentation in a Franz diffusion cell. PMID:23121937

  19. Peptide-decorated chitosan derivatives enhance fibroblast adhesion and proliferation in wound healing.

    PubMed

    Patrulea, V; Hirt-Burri, N; Jeannerat, A; Applegate, L A; Ostafe, V; Jordan, O; Borchard, G

    2016-05-20

    RGD peptide sequences are known to regulate cellular activities by interacting with α5β1, αvβ5 and αvβ3 integrin, which contributes to the wound healing process. In this study, RGDC peptide was immobilized onto chitosan derivative 1,6-diaminohexane-O-carboxymethyl-N,N,N-trimethyl chitosan (DAH-CMTMC) to display RGDC-promoting adhesion for enhanced wound healing. The efficiency of N-methylation, O-carboxymethylation and spacer grafting was quantitatively and qualitatively analyzed by (1)H NMR and FTIR, yielding 0.38 degree of substitution for N-methylation and >0.85 for O-carboxymethylation. The glass transition temperatures for chitosan derivatives were also studied. Peptide immobilization was achieved through sulfhydryl groups using sulfosuccinimidyl (4-iodoacetyl)amino-benzoate (sulfo-SIAB method). RGDC immobilized peptide onto DAH-CMTMC was found to be about 15.3 μg/mg of chitosan derivative by amino acid analysis (AAA). The significant increase of human dermal fibroblast (HDF) viability in vitro over 7 days suggests that RGDC-functionalized chitosan may lead to enhanced wound healing (viability >140%). Moreover, bio-adhesion and proliferation assays confirmed that coatings of RGDC-functionalized chitosan derivatives exhibit in vitro wound healing properties by enhancing fibroblast proliferation and adhesion. These results showed that RGDC peptide-functionalized chitosan provides an optimal environment for fibroblast adhesion and proliferation. PMID:26917381

  20. The Use of chitosan in The Formation of Silver Nanoparticles, Chitosanic Nanoparticles and Fibrous Structures

    NASA Astrophysics Data System (ADS)

    Abdelgawad, Abdelrahman Mohamed

    Nanoscale materials have attracted much attention in the last two decades due to their unique properties. The size effect attains new chemical and physical properties to these materials. Nanoparticles and nanofiber are major component of nanomaterials and they have heavily investigated in the literature for different applications. Nanoparticles could be produced from both metals as well as polymers. Chitosan, which is a natural polymer, can be used as capping agent in the preparation of metallic nanoparticles and itself, can produce nanoparticles. The utilization of nanoparticles and nanofibers for wound dressing materials is a very popular approach. Acquiring antibacterial properties to the wound dressing materials could be obtained either by formulation of nanomaterials composites or direct chemical modification of the substance. To improve the antibacterial properties of chitosan two approaches were applied. First, is through the formulation of chitosan with silver nanoparticles and the formation of nanofiber mats. In this study, the concepts of green chemistry were applied and silver nanoparticles were prepared in high concentration using chitosan as a capping polymer and glucose as a reducing agent. Nanofiber mats of polyvinyl alcohol/chitosan/silvernanoparticles were produced via electrospinning. The antibacterial activity of these fibers shows bactericidal effect against E. coli at low concentrations of Ag-NPs. In the second approach, direct chemical modification of chitosan was performed by grafting of Iodoacetic acid to the amino group at carbon-2. The chemical structure of chitosan Iodoacetamide derivative (CIA) was confirmed by FTIR and H1-NMR. The derivative was amorphous and water soluble at neutral pH. The minimum inhibitory concentration of CIA, against E. coli, was 400ig/mL and the derivative was bacteriostatic after 4h of treatment. Nanofiber mats of polyvinyl alcohol/chitosan/chitosan Iodoacetamide were produced via electrospinning. The

  1. Highly sensitive colorimetric detection of glucose and uric acid in biological fluids using chitosan-modified paper microfluidic devices.

    PubMed

    Gabriel, Ellen F M; Garcia, Paulo T; Cardoso, Thiago M G; Lopes, Flavio M; Martins, Felipe T; Coltro, Wendell K T

    2016-08-01

    This paper describes the modification of microfluidic paper-based analytical devices (μPADs) with chitosan to improve the analytical performance of colorimetric measurements associated with enzymatic bioassays. Chitosan is a natural biopolymer extensively used to modify biosensing surfaces due to its capability of providing a suitable microenvironment for the direct electron transfer between an enzyme and a reactive surface. This hypothesis was investigated using glucose and uric acid (UA) colorimetric assays as model systems. The best colorimetric sensitivity for glucose and UA was achieved using a chromogenic solution composed of 4-aminoantipyrine and sodium 3,5-dichloro-2-hydroxy-benzenesulfonate (4-AAP/DHBS), which provided a linear response for a concentration range between 0.1 and 1.0 mM. Glucose and UA were successfully determined in artificial serum samples with accuracies between 87 and 114%. The limits of detection (LODs) found for glucose and UA assays were 23 and 37 μM, respectively. The enhanced analytical performance of chitosan-modified μPADs allowed the colorimetric detection of glucose in tear samples from four nondiabetic patients. The achieved concentration levels ranged from 130 to 380 μM. The modified μPADs offered analytical reliability and accuracy as well as no statistical difference from the values achieved through a reference method. Based on the presented results, the proposed μPAD can be a powerful alternative tool for non-invasive glucose analysis. PMID:27272206

  2. Induction of aromatic amino acids and phenylpropanoid compounds in Scrophularia striata Boiss. cell culture in response to chitosan-induced oxidative stress.

    PubMed

    Kamalipourazad, Maryam; Sharifi, Mohsen; Maivan, Hassan Zare; Behmanesh, Mehrdad; Chashmi, Najmeh Ahmadian

    2016-10-01

    Manipulation of cell culture media by elicitors is one of most important strategies to inducing secondary metabolism for the production of valuable metabolites. In this investigation, inducing effect of chitosan on physiological, biochemical, and molecular parameters were investigated in cell suspension cultures of Scrophularia striata Boiss. The results showed that chitosan concentration and time of elicitation are determinants of the effectiveness of the elicitor. Accumulation of aromatic amino acids (phenylalanine [Phe] and tyrosine [Tyr]), phenylpropanoid compounds (phenolic acids [PAs] and echinacoside [ECH]), hydrogen peroxide (H2O2) production, phenylalanine ammonia-lyase (PAL) activity and gene expression, and antioxidant enzymes (superoxide dismutase [SOD], peroxidase [POX], catalase [CAT]) activities were altered by changing the exposure time of elicitation. Results showed that, upon elicitation with chitosan, oxidative events were induced, antioxidant responses of S. striata cells were boosted through enhanced activity of an effective series of scavenging enzymes (SOD, CAT, and POX), and biosynthesis of non-enzymatic antioxidants (ECH and PAs [cinnamic, p-coumaric and, caffeic acids]). The increase in amino acid content and PAL activity at early days of exposure to chitosan was related with rises in phenolic compounds. These results provide evidence that chitosan by up-regulation of PAL gene differentially improves the production of phenylpropanoid compounds, which are of medical commercial value with good biotechnological prospects. PMID:27392152

  3. Highly hydrophilic ultra-high molecular weight polyethylene powder and film prepared by radiation grafting of acrylic acid

    NASA Astrophysics Data System (ADS)

    Wang, Honglong.; Xu, Lu.; Li, Rong.; Pang, Lijuan.; Hu, Jiangtao.; Wang, Mouhua.; Wu, Guozhong.

    2016-09-01

    The surface properties of ultra-high molecular weight polyethylene (UHMWPE) are very important for its use in engineering or composites. In this work, hydrophilic UHMWPE powder and film were prepared by γ-ray pre-irradiation grafting of acrylic acid (AA) and further neutralization with sodium hydroxide solution. Variations in the chemical structure, grafting yield and hydrophilicity were investigated and compared. FT-IR and XPS analysis results showed that AA was successfully grafted onto UHMWPE powder and film; the powder was more suitable for the grafting reaction in 1 wt% AA solution than the film. Given a dose of 300 kGy, the grafting yield of AA was ∼5.7% for the powder but ∼0.8% for the film under identical conditions. Radiation grafting of a small amount of AA significantly improved the hydrophilicity of UHMWPE. The water contact angle of the UHMWPE-g-PAA powder with a grafting yield of AA at ∼5.7% decreased from 110.2° to 68.2°. Moreover, the grafting powder (UHMWPE-g-PAA) exhibited good dispersion ability in water.

  4. The effect of butyric acid with autogenous omental graft on healing of experimental Achilles tendon injury in rabbits

    PubMed Central

    Jahani, S; Moslemi, H. R.; Dehghan, M. M.; Sedaghat, R; Mazaheri Nezhad, R; Rezaee Moghaddam, D

    2015-01-01

    In this study, the role of local injection of butyric acid (BA) with autogenous omental graft was evaluated in healing of experimental Achilles tendon injury in rabbits. Nine adult male New Zealand rabbits were anesthetized and a partial thickness tenotomy was created on both hindlimbs. In treated group, omental graft was secured in place using BA soaked polygalactin 910 suture. In control group, the graft was sutured without BA. Butyric acid and normal saline were injected daily to treatment and control groups for three days, respectively. Based on the findings, on day 15 after injury, the tendon sections showed that healing rate in BA treated group was higher than that in control group. Furthermore, at days 28 and 45, comparison between BA treated and control groups demonstrated that BA increased the healing rate but with no significance. In summary, results of this study show that application of BA with autogenous omental graft can improve healing process of damaged Achilles tendon. PMID:27175160

  5. Molecularly imprinted poly(N-vinyl imidazole) based polymers grafted onto nonwoven fabrics for recognition/removal of phloretic acid

    NASA Astrophysics Data System (ADS)

    Llorina Rañada, Ma.; Akbulut, Meshude; Abad, Lucille; Güven, Olgun

    2014-01-01

    A solution of N-vinyl imidazole (VIm), ethylene glycol dimethylacrylate (EGDMA), and phloretic acid (p-hydroxyphenylpropionic acid, HPPA) as functional monomer, crosslinker and template, respectively, were used to graft molecularly imprinted polymer (MIP) onto polyethylene/polypropylene (PE/PP) nonwoven fabric via gamma radiation at room temperature. Control grafted films were also synthesized using the same procedure in the absence of HPPA. Binding performance of the MIP grafts was investigated for different template molecule concentrations and contact time. An imprinting factor for the sample prepared at 5 kGy dose was determined as 2.41 for 50 ppm HPPA solution for 3-h incubation. MIP graft layers were investigated by positron annihilation lifetime spectroscopy (PALS) as well as SEM.

  6. Comparative Biomechanical and Microstructural Analysis of Native versus Peracetic Acid-Ethanol Treated Cancellous Bone Graft

    PubMed Central

    Rauh, Juliane; Despang, Florian; Baas, Jorgen; Liebers, Cornelia; Pruss, Axel; Günther, Klaus-Peter; Stiehler, Maik

    2014-01-01

    Bone transplantation is frequently used for the treatment of large osseous defects. The availability of autologous bone grafts as the current biological gold standard is limited and there is a risk of donor site morbidity. Allogenic bone grafts are an appealing alternative, but disinfection should be considered to reduce transmission of infection disorders. Peracetic acid-ethanol (PE) treatment has been proven reliable and effective for disinfection of human bone allografts. The purpose of this study was to evaluate the effects of PE treatment on the biomechanical properties and microstructure of cancellous bone grafts (CBG). Forty-eight human CBG cylinders were either treated by PE or frozen at −20°C and subjected to compression testing and histological and scanning electron microscopy (SEM) analysis. The levels of compressive strength, stiffness (Young's modulus), and fracture energy were significantly decreased upon PE treatment by 54%, 59%, and 36%, respectively. Furthermore, PE-treated CBG demonstrated a 42% increase in ultimate strain. SEM revealed a modified microstructure of CBG with an exposed collagen fiber network after PE treatment. We conclude that the observed reduced compressive strength and reduced stiffness may be beneficial during tissue remodeling thereby explaining the excellent clinical performance of PE-treated CBG. PMID:24678514

  7. Graft Loss Due to Percutaneous Sclerotherapy of a Lymphocele Using Acetic Acid After Renal Transplantation

    SciTech Connect

    Adani, Gian Luigi Baccarani, Umberto; Bresadola, Vittorio; Lorenzin, Dario; Montanaro, Domenico; Risaliti, Andrea; Terrosu, Giovanni; Sponza, Massimo; Bresadola, Fabrizio

    2005-12-15

    Development of lymphoceles after renal transplantation is a well-described complication that occurs in up to 40% of recipients. The gold standard approach for the treatment of symptomatic cases is not well defined yet. Management options include simple aspiration, marsupialization by a laparotomy or laparoscopy, and percutaneous sclerotherapy using different chemical agents. Those approaches can be associated, and they depend on type, dimension, and localization of the lymphocele. Percutaneous sclerotherapy is considered to be less invasive than the surgical approach; it can be used safely and effectively, with low morbidity, in huge, rapidly accumulating lymphoceles. Moreover, this approach is highly successful, and the complication rate is acceptable; the major drawback is a recurrence rate close to 20%. We herewith report a renal transplant case in which the patient developed a symptomatic lymphocele that was initially treated by ultrasound-guided percutaneous sclerotherapy with ethanol and thereafter using acetic acid for early recurrence. A few hours after injection of acetic acid in the lymphatic cavity, the patient started to complain of acute pain localized to the renal graft and fever. An ultrasound of the abdomen revealed thrombosis of the renal vein and artery. The patient was immediately taken to the operating room, where the diagnosis of vascular thrombosis was confirmed and the graft was urgently explanted. In conclusion, we strongly suggest avoiding the use of acetic acid as a slerosating agent for the percutaneous treatment of post-renal transplant lymphocele because, based on our experience, it could be complicated by vascular thrombosis of the kidney, ending in graft loss.

  8. Microwave plasma induced grafting of oleic acid on cotton fabric surfaces

    NASA Astrophysics Data System (ADS)

    Cabrales, Luis; Abidi, Noureddine

    2012-03-01

    Cotton fabric surface was successfully functionalized with microwave plasma (2.45 GHz, 500 W) to impart water repellency. The hydrophobic agent used was oleic acid (CH3(CH2)7CHdbnd CH(CH2)7COOH), a fatty acid derived from various plant seed oils. Non-polymerizing gas (Argon) was used to create the plasma. The exposure of the cellulose to Ar-plasma generated radicals, which were subsequently used to initiate co-polymerization reactions with oleic acid. The FTIR spectra showed the presence of additional vibrations located at 2918, 2849, and 1707 cm-1 in the functionalized samples. Dynamic contact angle measurements were performed to assess the hydrophobic properties of the functionalized cotton fabric. The grafted cotton fabric showed excellent water repellency. In addition, the use of plant-derived monomers and biopolymers provides a different approach to use renewable resources to create functionalized biopolymeric substrates.

  9. Investigating the Properties and Hydrolysis Ability of Poly-Lactic Acid/Chitosan Nanocomposites Using Polycaprolactone.

    PubMed

    Trang, Nguyen Thi Thu; Chinhl, Nguyen Thuy; Thanh, Dinh Thi Mai; Hang, To Thi Xuan; Giang, Nguyen Vu; Hoang, Thai; Quan, Pham Minh; Giang, Le Duc; Thai, Nguyen Viet; Lawrence, Geoffrey

    2015-12-01

    Poly-lactic acid (PLA) has been widely applied in the medical field (in biomedicines such as medical capsules, surgical sutures and suture wounds) owing to its high biodegradability, good biocompatibility and ability to be dissolved in common solvents. Chitosan (CS) is an abundant polysaccharide and a cationic polyelectrolyte present in nature. In this study, the combination of PLA and CS has been used to form PLA/CS nanocomposites having the advantages of both the original components. To enhance the dispersibility and compatibility between PLA and CS in the PLA/CS nanocomposites, polycaprolactone (PCL) is added as a compatibilizer. The Fourier Transform Infrared spectroscopies prove the existence of the interactions of PCL with PLA and CS. A more regular dispersion of CS of 200-400 nm particle size, is observed in the PLA matrix of the PLA/CS nanocomposites containing PCL, through the Field Emission Scanning Electron Microscopy images. The appearance of one glass transition temperature (T(g)) value of PLA/CS/PCL nanocomposites occuring between the T(g) values of PLA and CS in DSC diagrams confirms the improvement in the compatibility between PLA and CS, due to the presence of PCL. The TGA result shows that PCL plays an important role in enhancing the thermal stability of PLA/CS/PCL nanocomposites. The hydrolysis of PLA/CS/PCL nanocomposites in alkaline and phosphate buffer solutions was investigated. The obtained results show that the PLA/CS/PCL nanocomposites have slower hydrolysis ability than the PLA/CS composites. PMID:26682382

  10. Positronium Formation Of Glyeisdyl Methacrylic Acid (GMA)/Styrene Grafted On PVDF Membrane For Fuel Cells

    SciTech Connect

    Abdel-Hady, E. E.; Abdel-Hamed, M. O.; Eltonny, M. M.

    2011-06-01

    Simultaneous gamma irradiation was used effectively for grafting of glycidyl methacrylic acid and styrene onto Poly vinyldine fluoride (PVDF). Membranes were characterized by thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM). The properties of the obtained membranes were evaluated in terms of proton conductivity, methanol permeability and positron annihilation lifetime (PALS) parameters. The high probability of Positronium formation enables the application of PALS to the study of free volume. Good property values approved the applicability of the membrane from the cost benefit point of view.

  11. Synthesis of nanosilver loaded chitosan/poly(acrylamide-co-itaconic acid) based inter-polyelectrolyte complex films for antimicrobial applications.

    PubMed

    Bajpai, S K; Jyotishi, Pooja; Bajpai, M

    2016-12-10

    In the present work, AgNPs loaded chitosan/poly(acrylamide-co-itaconic acid) inter-polyelectrolyte complex (IPC) films have been prepared for antimicrobial applications. The AgNPs-loaded IPC films have been characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA) and Surface plasmon resonance (SPR). Particle size of synthesized AgNPs was found to be in the range 10-30nm. These films exhibited a remarkable antibacterial property against strong pathogen E.Coli, thus offering their candidature for antimicrobial applications. PMID:27577913

  12. Ferulic acid-coupled chitosan: thermal stability and utilization as an antioxidant for biodegradable active packaging film.

    PubMed

    Woranuch, Sarekha; Yoksan, Rangrong; Akashi, Mitsuru

    2015-01-22

    The aim of the present research was to study the thermal stability of ferulic acid after coupling onto chitosan, and the possibility of using ferulic acid-coupled chitosan (FA-CTS) as an antioxidant for biodegradable active packaging film. FA-CTS was incorporated into biodegradable film via a two-step process, i.e. compounding extrusion at temperatures up to 150°C followed by blown film extrusion at temperatures up to 175°C. Although incorporation of FA-CTS with a content of 0.02-0.16% (w/w) caused decreased water vapor barrier property and reduced extensibility, the biodegradable films possessed improved oxygen barrier property and antioxidant activity. Radical scavenging activity and reducing power of film containing FA-CTS were higher than those of film containing naked ferulic acid, by about 254% and 94%, respectively. Tensile strength and rigidity of the films were not significantly affected by the addition of FA-CTS with a content of 0.02-0.08% (w/w). The above results suggested that FA-CTS could potentially be used as an antioxidant for active packaging film. PMID:25439957

  13. Fluorescent Boronic Acid Polymer Grafted on Silica Particles for Affinity Separation of Saccharides

    PubMed Central

    2014-01-01

    Boronic acid affinity gels are important for effective separation of biological active cis-diols, and are finding applications both in biotech industry and in biomedical research areas. To increase the efficacy of boronate affinity separation, it is interesting to introduce repeating boronic acid units in flexible polymer chains attached on solid materials. In this work, we synthesize polymer brushes containing boronic acid repeating units on silica gels using surface-initiated atom transfer radical polymerization (ATRP). A fluorescent boronic acid monomer is first prepared from an azide-tagged fluorogenic boronic acid and an alkyne-containing acrylate by Cu(I)-catalyzed 1,3-dipolar cycloaddition reaction (the CuAAC click chemistry). The boronic acid monomer is then grafted to the surface of silica gel modified with an ATRP initiator. The obtained composite material contains boronic acid polymer brushes on surface and shows favorable saccharide binding capability under physiological pH conditions, and displays interesting fluorescence intensity change upon binding fructose and glucose. In addition to saccharide binding, the flexible polymer brushes on silica also enable fast separation of a model glycoprotein based on selective boronate affinity interaction. The synthetic approach and the composite functional material developed in this work should open new opportunities for high efficiency detection, separation, and analysis of not only simple saccharides, but also glycopeptides and large glycoproteins. PMID:24444898

  14. Fluorescent boronic acid polymer grafted on silica particles for affinity separation of saccharides.

    PubMed

    Xu, Zhifeng; Uddin, Khan Mohammad Ahsan; Kamra, Tripta; Schnadt, Joachim; Ye, Lei

    2014-02-12

    Boronic acid affinity gels are important for effective separation of biological active cis-diols, and are finding applications both in biotech industry and in biomedical research areas. To increase the efficacy of boronate affinity separation, it is interesting to introduce repeating boronic acid units in flexible polymer chains attached on solid materials. In this work, we synthesize polymer brushes containing boronic acid repeating units on silica gels using surface-initiated atom transfer radical polymerization (ATRP). A fluorescent boronic acid monomer is first prepared from an azide-tagged fluorogenic boronic acid and an alkyne-containing acrylate by Cu(I)-catalyzed 1,3-dipolar cycloaddition reaction (the CuAAC click chemistry). The boronic acid monomer is then grafted to the surface of silica gel modified with an ATRP initiator. The obtained composite material contains boronic acid polymer brushes on surface and shows favorable saccharide binding capability under physiological pH conditions, and displays interesting fluorescence intensity change upon binding fructose and glucose. In addition to saccharide binding, the flexible polymer brushes on silica also enable fast separation of a model glycoprotein based on selective boronate affinity interaction. The synthetic approach and the composite functional material developed in this work should open new opportunities for high efficiency detection, separation, and analysis of not only simple saccharides, but also glycopeptides and large glycoproteins. PMID:24444898

  15. Preconcentration and Determination of Mefenamic Acid in Pharmaceutical and Biological Fluid Samples by Polymer-grafted Silica Gel Solid-phase Extraction Following High Performance Liquid Chromatography

    PubMed Central

    Bagheri Sadeghi, Hayedeh; Panahi, Homayon Ahmad; Mahabadi, Mahsa; Moniri, Elham

    2015-01-01

    Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) that has analgesic, anti-infammatory and antipyretic actions. It is used to relieve mild to moderate pains. Solid-phase extraction of mefenamic acid by a polymer grafted to silica gel is reported. Poly allyl glycidyl ether/iminodiacetic acid-co-N, N-dimethylacrylamide was synthesized and grafted to silica gel and was used as an adsorbent for extraction of trace mefenamic acid in pharmaceutical and biological samples. Different factors affecting the extraction method were investigated and optimum conditions were obtained. The optimum pH value for sorption of mefenamic acid was 4.0. The sorption capacity of grafted adsorbent was 7.0 mg/g. The best eluent solvent was found to be trifluoroacetic acid-acetic acid in methanol with a recovery of 99.6%. The equilibrium adsorption data of mefenamic acid by grafted silica gel was analyzed by Langmuir model. The conformation of obtained data to Langmuir isotherm model reveals the homogeneous binding sites of grafted silica gel surface. Kinetic study of the mefenamic acid sorption by grafted silica gel indicates the good accessibility of the active sites in the grafted polymer. The sorption rate of the investigated mefenamic acid on the grafted silica gel was less than 5 min. This novel synthesized adsorbent can be successfully applied for the extraction of trace mefenamic acid in human plasma, urine and pharmaceutical samples. PMID:26330865

  16. Protein, cell and bacterial response to atmospheric pressure plasma grafted hyaluronic acid on poly(methylmethacrylate).

    PubMed

    D'Sa, Raechelle A; Raj, Jog; Dickinson, Peter J; McMahon, M Ann S; McDowell, David A; Meenan, Brian J

    2015-11-01

    Hyaluronic acid (HA) has been immobilised on poly(methyl methacrylate) (PMMA) surfaces using a novel dielectric barrier discharge (DBD) plasma process for the purposes of repelling protein, cellular and bacterial adhesion in the context of improving the performance of ophthalmic devices. Grafting was achieved by the following steps: (1) treatment of the PMMA with a DBD plasma operating at atmospheric pressure, (2) amine functionalisation of the activated polymer surface by exposure to a 3-aminopropyltrimethoxysilane (APTMS) linker molecule and (3) reaction of HA with the surface bound amine. The mechanism and effectiveness of the grafting process was verified by surface analysis. XPS data indicates that the APTMS linker molecule binds to PMMA via the Si-O chemistry and has the required pendant amine moiety. The carboxylic acid moiety on HA then binds with this -NH2 group via standard carbodiimide chemistry. ToF-SIMS confirms the presence of a coherent HA layer the microstructure of which is verified by AFM. The plasma grafted HA coating surfaces showed a pronounced decrease in protein and cellular adhesion when tested with bovine serum albumin and human corneal epithelial cells, respectively. The ability of these coatings to resist bacterial adhesion was established using Staphylococcus aureus NTC8325. Interestingly, the coatings did not repel bacterial adhesion, indicating that the mechanism of adhesion of bacterial cells is different to that for the surface interactions of mammalian cells. It is proposed that this difference is a consequence of the specific HA conformation that occurs under the conditions employed here. Hence, it is apparent that the microstructure/architecture of the HA coatings is an important factor in fabricating surfaces intended to repel proteins, mammalian and bacterial cells. PMID:26449450

  17. Single-layer MoS2 nanosheet grafted upconversion nanoparticles for near-infrared fluorescence imaging-guided deep tissue cancer phototherapy.

    PubMed

    Han, Jianyu; Xia, Hongping; Wu, Yafeng; Kong, Shik Nie; Deivasigamani, Amudha; Xu, Rong; Hui, Kam M; Kang, Yuejun

    2016-04-21

    A multifunctional nanostructure is prepared by covalently grafting upconversion nanoparticles (UCNPs) with chitosan functionalized MoS2 (MoS2-CS) and folic acid (FA) and then loading phthalocyanine (ZnPc) on the surface of MoS2, which integrates photodynamic therapy (PDT) with photothermal therapy (PTT) and upconversion luminescence imaging into one system for enhanced antitumor efficiency. PMID:27035265

  18. Preparation of starch-poly-glutamic acid graft copolymers by microwave irradiation and the characterization of their properties.

    PubMed

    Xu, Jingyuan; Krietemeyer, Elizabeth F; Finkenstadt, Victoria L; Solaiman, Daniel; Ashby, Richard D; Garcia, Rafael A

    2016-04-20

    Graft copolymers of waxy maize starch and poly-γ-glutamic acid (PGA) were produced in an aqueous solution using microwave irradiation. The microwave reaction conditions were optimized with regard to temperature and pH. The temperature of 180°C and pH7.0 were the best reaction conditions resulting in a PGA graft of 0.45% based on nitrogen analysis. The average graft content and graft efficiency for the starch-PGA graft copolymer prepared at 180°C and pH7.0 were 4.20% and 2.73%, respectively. The starch-PGA graft copolymer produced at 180°C and pH7.0 could absorb more than 20 times its own weight amount of water and form a gel. The preliminary rheology study revealed that the starch-PGA graft copolymer gel exhibited viscoelastic solid behavior while the control sample of waxy starch showed viscoelastic liquid behavior. PMID:26876849

  19. Acidic proteases from Monterey sardine (Sardinops sagax caerulea) immobilized on shrimp waste chitin and chitosan supports: searching for a by-product catalytic system.

    PubMed

    Salazar-Leyva, Jesus Aaron; Lizardi-Mendoza, Jaime; Ramirez-Suarez, Juan Carlos; Valenzuela-Soto, Elisa Miriam; Ezquerra-Brauer, Josafat Marina; Castillo-Yañez, Francisco Javier; Pacheco-Aguilar, Ramon

    2013-10-01

    Solid wastes generated from the seafood industry represent an important environmental pollutant; therefore, utilization of those wastes for the development of processing biochemical tools could be an attractive and clean solution for the seafood industry. This study reports the immobilization of semi-purified acidic proteases from Monterey sardine stomachs onto chitin and chitosan materials extracted from shrimp head waste. Several supports (chitosan beads, chitosan flakes, and partially deacetylated flakes) were activated either with genipin or Na-tripolyphosphate and evaluated as a mean to immobilize acidic proteases. The protein load varied within the 67-91% range on different supports. The immobilization systems based on chitosan beads achieved the highest protein loads but showed the lowest retained catalytic activities. The best catalytic behavior was obtained using partially deacetylated chitin flakes activated either with genipin or Na-tripolyphosphate. According to results, the immobilization matrix structure, as well as acetylation degree of chitin-chitosan used, has considerable influence on the catalytic behavior of immobilized proteases. Partially deacetylated chitin flakes represent a suitable option as support for enzyme immobilization because its preparation requires fewer steps than other supports. Two abundant seafood by-products were used to obtain a catalytic system with enough proteolytic activity to be considered for biotechnological applications in diverse fields. PMID:23897542

  20. Preparation of polyelectrolyte complex nanoparticles of chitosan and poly(2-acry1amido-2-methylpropanesulfonic acid) for doxorubicin release.

    PubMed

    Zhang, Liping; Wang, Jie; Ni, Caihua; Zhang, Yanan; Shi, Gang

    2016-01-01

    A new kind of polyelectrolyte complex (PEC) based on cationic chitosan (CS) and anionic poly(2-acry1amido-2-methylpropanesulfonic acid) (PAMPS) was prepared using a polymer-monomer pair reaction system. Chitosan was mixed with 2-acry1amido-2-methylpropanesulfonic acid) (AMPS) in an aqueous solution, followed by polymerization of AMPS. The complex was formed by electrostatic interaction of NH3(+) groups of CS and SO3(-) groups of AMPS, leading to a formation of complex nanoparticles of CS-PAMPS. A series of nanoparticles were obtained by changing the weight ratio of CS to AMPS, the structure and properties of nanoparticles were investigated. It was observed that the nanoparticles possessed spherical morphologies with average diameters from 255 nm to 390 nm varied with compositions of the nanoparticles. The nanoparticles were used as drug vehicles for doxorubicin, displaying relative high drug loading rate and encapsulation rate. The vitro release profiles revealed that the drug release could be controlled by adjusting pH of the release media. The nanoparticles demonstrated apparent advantages such as simple preparation process, free of organic solvents, size controllable, good biodegradability and biocompatibility, and they could be potentially used in drug controlled release field. PMID:26478364

  1. Functional and surface-active membranes from poly(vinylidene fluoride)-graft-poly(acrylic acid) prepared via RAFT-mediated graft copolymerization.

    PubMed

    Ying, L; Yu, W H; Kang, E T; Neoh, K G

    2004-07-01

    Poly (vinylidene fluoride) (PVDF) with "living" poly (acrylic acid) (PAAc) side chains (PVDF-g-PAAc) was prepared by reversible addition-fragmentation chain transfer (RAFT)-mediated graft copolymerization of acrylic acid (AAc) with the ozone-pretreated PVDF. The chemical composition and structure of the copolymers were characterized by elemental analysis, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The copolymer could be readily cast into pH-sensitive microfiltration (MF) membranes with enriched living PAAc graft chains on the surface (including the pore surfaces) by phase inversion in an aqueous medium. The surface composition of the membranes was determined by X-ray photoelectron spectroscopy. The morphology of the membranes was characterized by scanning electron microscopy. The pore size distribution of the membranes was found to be much more uniform than that of the corresponding membranes cast from PVDF-g-PAAc prepared by the "conventional" free-radical graft copolymerization process. Most important of all, the MF membranes with surface-tethered PAAc macro chain transfer agents, or the living membrane surfaces, could be further functionalized via surface-initiated block copolymerization with N-isopropylacrylamide (NIPAAM) to obtain the PVDF-g-PAAc-b-PNIPAAM MF membranes, which exhibited both pH- and temperature-dependent permeability to aqueous media. PMID:16459627

  2. Effect of PEGylation on the toxicity and permeability enhancement of chitosan.

    PubMed

    Casettari, Luca; Vllasaliu, Driton; Mantovani, Giuseppe; Howdle, Steven M; Stolnik, Snow; Illum, Lisbeth

    2010-11-01

    The aim of the present work is to investigate if conditions can be devised where PEGylation of chitosan would reduce its toxicity toward the nasal mucosa while maintaining its ability to open the cellular tight junctions and, consequently, produce an enhancement of macromolecular permeability. A series of mPEG-g-chitosan copolymers with varying levels of mPEG substitution, mPEG molecular weight, and chitosan molecular weight were synthesized by grafting carboxylic acid-terminated mPEGs (Mw 1.9 and 5.0 × 10(3) g mol(-1)) to chitosans (Mw 28.9 and 82.0 × 10(3) g mol(-1)) using a NHS/EDC coupling system. The synthesized mPEG-g-chitosans were fully characterized using a number of techniques, including FT-IR, (1)H NMR, and SEC-MALLS and their physicochemical properties were analyzed by TGA and DSC. Thereafter, the conjugates were tested for their cytotoxicity and tight junction modulating property in a relevant cell model, a mucus producing Calu-3 monolayer. mPEG-g-chitosan conjugates exhibited reduced toxicity toward cells, as compared to unmodified chitosan counterparts. Furthermore, the conjugates demonstrated a dramatic effect on cell monolayer transepithelial electrical resistance (TEER) and enhancement of permeability of model macromolecules. TEER and permeability-enhancing effects, as measurable indicators of tight junction modulation, were found to be pH-dependent and were notably more pronounced than those exhibited by unmodified chitosans. This work therefore demonstrates that conditions can be contrived where PEGylation improves the toxicity profile of chitosan, while preserving its effect on epithelial tight junctions in the nose. PMID:20873757

  3. Relevant insight of surface characterization techniques to study covalent grafting of a biopolymer to titanium implant and its acidic resistance

    NASA Astrophysics Data System (ADS)

    D'Almeida, Mélanie; Amalric, Julien; Brunon, Céline; Grosgogeat, Brigitte; Toury, Bérangère

    2015-02-01

    Peri-implant bacterial infections are the main cause of complications in dentistry. Our group has previously proposed the attachment of chitosan on titanium implants via a covalent bond to improve its antibacterial properties while maintaining its biocompatibility. A better knowledge of the coating preparation process allows a better understanding of the bioactive coating in biological conditions. In this work, several relevant characterization techniques were used to assess an implant device during its production phase and its resistance in natural media at different pH. The titanium surface was functionalized with 3-aminopropyltriethoxysilane (APTES) followed by grafting of an organic coupling agent; succinic anhydride, able to form two covalent links, with the substrate through a Ti-O-Si bond and the biopolymer through a peptide bond. Each step of the coating synthesis as well as the presence confirmation of the biopolymer on titanium after saliva immersion was followed by FTIR-ATR, SEM, EDS, 3D profilometry, XPS and ToF-SIMS analyses. Results allowed to highlight the efficiency of each step of the process, and to propose a mechanism occurring during the chitosan coating degradation in saliva media at pH 5 and at pH 3.

  4. Hydroxyapatite surface modified by L-lactic acid and its subsequent grafting polymerization of L-lactide.

    PubMed

    Qiu, Xueyu; Hong, Zhongkui; Hu, Junli; Chen, Li; Chen, Xuesi; Jing, Xiabin

    2005-01-01

    A new method of surface modification of hydroxyapatite nanoparticles (n-HA) by surface grafting reaction of l-lactic acid and ring-opening polymerization of l-lactide (LLA) was developed. Two modified HA nanoparticles were obtained: HA modified by l-lactic acid (l-HA) and HA grafting with poly(l-lactide) (PLLA; p-HA). The modified surface of n-HA was attested by Fourier transformation infrared, (31)P MAS NMR, and thermal gravimetric analysis. The results showed that l-lactic acid could be easily grafted onto the n-HA surface by forming a Ca carboxylate bond and initiated by the hydroxyl group of the grafted l-lactic acid and LLA could be graft-polymerized onto the n-HA surface in the presence of stannous octanoate. The highest grafting amounts of l-lactic acid and PLLA were about 33 and 22 wt %, respectively. The modified HA/PLLA composites showed good mechanical properties and uniform microstructure. The tensile strength and modulus of the p-HA/PLLA composite containing 15 wt % of p-HA were 67 MPa and 2.1 GPa, respectively, while those of the n-HA/PLLA composites were 45 MPa and 1.7 GPa, respectively. The elongation at the break of the l-HA/PLLA composite containing 15 wt % l-HA could reach 44%, in comparison with 6.5% of the n-HA/PLLA composites containing 15 wt % n-HA. PMID:15877333

  5. Determination of the degree of acetylation and the distribution of acetyl groups in chitosan by HPLC analysis of nitrous acid degraded and PMP labeled products.

    PubMed

    Han, Zhangrun; Zeng, Yangyang; Lu, Hong; Zhang, Lijuan

    2015-09-01

    Chitin is one of the most abundant polysaccharides on earth. It consists of repeating β-1,4 linked N-acetylated glucosamine (A) units. Chitosan is an N-deacetylated product of chitin. Chitosan and its derivatives have broad medical applications as drugs, nutraceuticals, or drug delivery agents. However, a reliable analytical method for quality control of medically used chitosans is still lacking. In current study, nitrous acid was used to cleave all glucosamine residues in chitosan into 2,5-anhydromannose (M) or M at the reducing end of di-, tri-, and oligosaccharides. PMP, i.e. 1-phenyl-3-methyl-5-pyrazolone, was used to label all the Ms. Online UV detection allowed quantification of all M-containing UV peaks whereas online MS analysis directly identified 11 different kinds of mono-, di-, tri-, and oligosaccharides that correlated each oligosaccharide with specific UV peak after HPLC separation. The DA (degree of acetylation) for chitosans was calculated based on the A/(A+M) value derived from the UV data. This newly developed method had several advantages for quality control of chitosan: 1. the experimental procedures were extensively optimized; 2. the reliability of the method was confirmed by online LC-MS analysis; 3. the DA value was obtainable based on the UV data after HPLC analysis, which was comparableto that of (1)H NMR and conductometric titration analyses; 4. finally and most importantly, this method could be used to obtain the DA as well as chemical acetylation/deacetylation mechanisms for chitosan by any laboratory equipped with a HPLC and an online UV detector. PMID:26114886

  6. Monitoring of ppm level humic acid in surface water using ZnO-chitosan nano-composite as fluorescence probe

    NASA Astrophysics Data System (ADS)

    Basumallick, Srijita; Santra, Swadeshmukul

    2015-05-01

    Surface water contains natural pollutants humic acid (HA) and fulvic acid at ppm level which form carcinogenic chloro-compounds during chlorination in water treatment plants. We report here synthesis of ZnO-chitosan (CS) nano-composites by simple hydrothermal technique and examined their application potential as fluorescent probe for monitoring ppm level HA. These ZnO-CS composites have been characterized by HRTEM, EDX, FTIR, AFM and Fluorescence Spectra. HRTEM images show the formation of ZnO-CS nano-composites of average diameter of 50-250 nm. Aqueous dispersions of these nano-composites show fluorescence emission at 395 nm when excited at 300 nm which is strongly quenched by ppm level HA indicating their possible use in monitoring ppm level HA present in surface water.

  7. UV-induced graft polymerization of acrylic acid in the sub-micronchannels of oxidized PET track-etched membrane

    NASA Astrophysics Data System (ADS)

    Korolkov, Ilya V.; Mashentseva, Anastassiya A.; Güven, Olgun; Taltenov, Abzal A.

    2015-12-01

    In this article, we report on functionalization of track-etched membrane based on poly(ethylene terephthalate) (PET TeMs) oxidized by advanced oxidation systems and by grafting of acrylic acid using photochemical initiation technique for the purpose of increasing functionality thus expanding its practical application. Among advanced oxidation processes (H2O2/UV) system had been chosen to introduce maximum concentration of carboxylic acid groups. Benzophenone (BP) photo-initiator was first immobilized on the surfaces of cylindrical pores which were later filled with aq. acrylic acid solution. UV-irradiation from both sides of PET TeMs has led to the formation of grafted poly(acrylic acid) (PAA) chains inside the membrane sub-micronchannels. Effect of oxygen-rich surface of PET TeMs on BP adsorption and subsequent process of photo-induced graft polymerization of acrylic acid (AA) were studied by ESR. The surface of oxidized and AA grafted PET TeMs was characterized by UV-vis, ATR-FTIR, XPS spectroscopies and by SEM.

  8. Chondroitin Sulfate, Hyaluronic Acid and Chitin/Chitosan Production Using Marine Waste Sources: Characteristics, Applications and Eco-Friendly Processes: A Review

    PubMed Central

    Vázquez, José Antonio; Rodríguez-Amado, Isabel; Montemayor, María Ignacia; Fraguas, Javier; del Pilar González, María; Murado, Miguel Anxo

    2013-01-01

    In the last decade, an increasing number of glycosaminoglycans (GAGs), chitin and chitosan applications have been reported. Their commercial demands have been extended to different markets, such as cosmetics, medicine, biotechnology, food and textiles. Marine wastes from fisheries and aquaculture are susceptible sources for polymers but optimized processes for their recovery and production must be developed to satisfy such necessities. In the present work, we have reviewed different alternatives reported in the literature to produce and purify chondroitin sulfate (CS), hyaluronic acid (HA) and chitin/chitosan (CH/CHs) with the aim of proposing environmentally friendly processes by combination of various microbial, chemical, enzymatic and membranes strategies and technologies. PMID:23478485

  9. Valproic Acid Ameliorates Graft-versus-Host Disease by Downregulating Th1 and Th17 Cells.

    PubMed

    Long, Jun; Chang, Li; Shen, Yan; Gao, Wen-Hui; Wu, Yue-Nv; Dou, Han-Bo; Huang, Meng-Meng; Wang, Ying; Fang, Wei-Yue; Shan, Jie-Hui; Wang, Yue-Ying; Zhu, Jiang; Chen, Zhu; Hu, Jiong

    2015-08-15

    Graft-versus-host disease (GVHD) is the major complication after allogeneic bone marrow transplantation. Valproic acid (VPA) was described as a histone deacetylase inhibitor that had anti-inflammatory effects and reduced the production of proinflammatory cytokines in experimental autoimmune disease models. Using well-characterized mouse models of MHC-mismatched transplantation, we studied the effects of VPA on GVHD severity and graft-versus-leukemia (GVL) activity. Administration of VPA significantly attenuated the clinical severity of GVHD, the histopathology of GVHD-involved organs, and the overall mortality from GVHD. VPA downregulated Th1 and Th17 cell responses and cytokine production in vitro and in vivo, whereas its effect on GVHD was regulatory T cell independent. The effect of VPA was related to its ability to directly reduce the activity of Akt, an important regulator of T cell immune responses. Importantly, when mice received lethal doses of host-type acute leukemia cells, administration of VPA did not impair GVL activity and resulted in significantly improved leukemia-free survival. These findings reveal a unique role for VPA as a histone deacetylase inhibitor in reducing the donor CD4(+) T cells that contribute to GVHD, which may provide a strategy to reduce GVHD while preserving the GVL effect. PMID:26179902

  10. Weathering and Biodegradation Study on Graft Copolymer Compatibilized Hybrid Bionanocomposites of Poly(Lactic Acid)

    NASA Astrophysics Data System (ADS)

    Sajna, VP; Nayak, Sanjay K.; Mohanty, Smita

    2016-06-01

    This work reports on the influence of moisture absorption and accelerated weathering on the properties of graft copolymer compatibilized bionanocomposites of poly(lactic acid) (PLA). Moisture absorption tests were conducted for 30 days by immersing the samples in a distilled water bath at room temperature, and the amount of moisture absorbed in each time interval was measured. The rate of moisture uptake decreased by incorporation of C30B nanoclay and graft copolymer into fiber-reinforced PLA composites. Changes in the mechanical properties of composites in each time interval of moisture absorption were investigated using tensile and impact tests. Exposure to moisture caused significant drops in the mechanical properties. The morphological characterization of biocomposites during the aforementioned tests has been made using SEM, while bionanocomposites were analyzed by TEM. Further, this paper also reported the effect of accelerated weathering on the mechanical properties and the results are confirmed through SEM analysis. Biodegradation behaviors of PLA biocomposites and bionanocomposites have also been studied.

  11. Weathering and Biodegradation Study on Graft Copolymer Compatibilized Hybrid Bionanocomposites of Poly(Lactic Acid)

    NASA Astrophysics Data System (ADS)

    Sajna, VP; Nayak, Sanjay K.; Mohanty, Smita

    2016-07-01

    This work reports on the influence of moisture absorption and accelerated weathering on the properties of graft copolymer compatibilized bionanocomposites of poly(lactic acid) (PLA). Moisture absorption tests were conducted for 30 days by immersing the samples in a distilled water bath at room temperature, and the amount of moisture absorbed in each time interval was measured. The rate of moisture uptake decreased by incorporation of C30B nanoclay and graft copolymer into fiber-reinforced PLA composites. Changes in the mechanical properties of composites in each time interval of moisture absorption were investigated using tensile and impact tests. Exposure to moisture caused significant drops in the mechanical properties. The morphological characterization of biocomposites during the aforementioned tests has been made using SEM, while bionanocomposites were analyzed by TEM. Further, this paper also reported the effect of accelerated weathering on the mechanical properties and the results are confirmed through SEM analysis. Biodegradation behaviors of PLA biocomposites and bionanocomposites have also been studied.

  12. Born energy, acid-base equilibrium, structure and interactions of end-grafted weak polyelectrolyte layers.

    PubMed

    Nap, R J; Tagliazucchi, M; Szleifer, I

    2014-01-14

    This work addresses the effect of the Born self-energy contribution in the modeling of the structural and thermodynamical properties of weak polyelectrolytes confined to planar and curved surfaces. The theoretical framework is based on a theory that explicitly includes the conformations, size, shape, and charge distribution of all molecular species and considers the acid-base equilibrium of the weak polyelectrolyte. Namely, the degree of charge in the polymers is not imposed but it is a local varying property that results from the minimization of the total free energy. Inclusion of the dielectric properties of the polyelectrolyte is important as the environment of a polymer layer is very different from that in the adjacent aqueous solution. The main effect of the Born energy contribution on the molecular organization of an end-grafted weak polyacid layer is uncharging the weak acid (or basic) groups and consequently decreasing the concentration of mobile ions within the layer. The magnitude of the effect increases with polymer density and, in the case of the average degree of charge, it is qualitatively equivalent to a small shift in the equilibrium constant for the acid-base equilibrium of the weak polyelectrolyte monomers. The degree of charge is established by the competition between electrostatic interactions, the polymer conformational entropy, the excluded volume interactions, the translational entropy of the counterions and the acid-base chemical equilibrium. Consideration of the Born energy introduces an additional energetic penalty to the presence of charged groups in the polyelectrolyte layer, whose effect is mitigated by down-regulating the amount of charge, i.e., by shifting the local-acid base equilibrium towards its uncharged state. Shifting of the local acid-base equilibrium and its effect on the properties of the polyelectrolyte layer, without considering the Born energy, have been theoretically predicted previously. Account of the Born energy leads

  13. Born energy, acid-base equilibrium, structure and interactions of end-grafted weak polyelectrolyte layers

    SciTech Connect

    Nap, R. J.; Tagliazucchi, M.; Szleifer, I.

    2014-01-14

    This work addresses the effect of the Born self-energy contribution in the modeling of the structural and thermodynamical properties of weak polyelectrolytes confined to planar and curved surfaces. The theoretical framework is based on a theory that explicitly includes the conformations, size, shape, and charge distribution of all molecular species and considers the acid-base equilibrium of the weak polyelectrolyte. Namely, the degree of charge in the polymers is not imposed but it is a local varying property that results from the minimization of the total free energy. Inclusion of the dielectric properties of the polyelectrolyte is important as the environment of a polymer layer is very different from that in the adjacent aqueous solution. The main effect of the Born energy contribution on the molecular organization of an end-grafted weak polyacid layer is uncharging the weak acid (or basic) groups and consequently decreasing the concentration of mobile ions within the layer. The magnitude of the effect increases with polymer density and, in the case of the average degree of charge, it is qualitatively equivalent to a small shift in the equilibrium constant for the acid-base equilibrium of the weak polyelectrolyte monomers. The degree of charge is established by the competition between electrostatic interactions, the polymer conformational entropy, the excluded volume interactions, the translational entropy of the counterions and the acid-base chemical equilibrium. Consideration of the Born energy introduces an additional energetic penalty to the presence of charged groups in the polyelectrolyte layer, whose effect is mitigated by down-regulating the amount of charge, i.e., by shifting the local-acid base equilibrium towards its uncharged state. Shifting of the local acid-base equilibrium and its effect on the properties of the polyelectrolyte layer, without considering the Born energy, have been theoretically predicted previously. Account of the Born energy leads

  14. Born energy, acid-base equilibrium, structure and interactions of end-grafted weak polyelectrolyte layers

    NASA Astrophysics Data System (ADS)

    Nap, R. J.; Tagliazucchi, M.; Szleifer, I.

    2014-01-01

    This work addresses the effect of the Born self-energy contribution in the modeling of the structural and thermodynamical properties of weak polyelectrolytes confined to planar and curved surfaces. The theoretical framework is based on a theory that explicitly includes the conformations, size, shape, and charge distribution of all molecular species and considers the acid-base equilibrium of the weak polyelectrolyte. Namely, the degree of charge in the polymers is not imposed but it is a local varying property that results from the minimization of the total free energy. Inclusion of the dielectric properties of the polyelectrolyte is important as the environment of a polymer layer is very different from that in the adjacent aqueous solution. The main effect of the Born energy contribution on the molecular organization of an end-grafted weak polyacid layer is uncharging the weak acid (or basic) groups and consequently decreasing the concentration of mobile ions within the layer. The magnitude of the effect increases with polymer density and, in the case of the average degree of charge, it is qualitatively equivalent to a small shift in the equilibrium constant for the acid-base equilibrium of the weak polyelectrolyte monomers. The degree of charge is established by the competition between electrostatic interactions, the polymer conformational entropy, the excluded volume interactions, the translational entropy of the counterions and the acid-base chemical equilibrium. Consideration of the Born energy introduces an additional energetic penalty to the presence of charged groups in the polyelectrolyte layer, whose effect is mitigated by down-regulating the amount of charge, i.e., by shifting the local-acid base equilibrium towards its uncharged state. Shifting of the local acid-base equilibrium and its effect on the properties of the polyelectrolyte layer, without considering the Born energy, have been theoretically predicted previously. Account of the Born energy leads

  15. pACC1 peptide loaded chitosan nanoparticles induces apoptosis via reduced fatty acid synthesis in MDA-MB-231 cells

    NASA Astrophysics Data System (ADS)

    Kaliaperumal, Jagatheesh; Hari, Natarajan; Pavankumar, Padarthi; Elangovan, Namasivayam

    2015-06-01

    The development of formulations with therapeutic peptides has been restricted to poor cell penetration and in this attempt; we developed pACC1 peptide loaded chitosan nanoparticles. The prepared nanoparticles were characterized with FT-IR, XRD, SEM and TEM. In addition, the suitable formulation was evaluated for hemocompatibility, plasma stability and embryo toxicity using Danio rerio embryo model. The results showed that pACC1 peptide loaded chitosan nanoparticles were compatible with plasma. They possess sustained release pattern and also found to be safe up to 300 mg/L in embryo toxicity tests. Cytotoxicity assays with MDA-MB-231 cell lines suggested that, pACC1 peptide loaded chitosan nanoparticles were capable of enhanced cellular penetration and reduced palmitic acid content, which was confirmed by H1 NMR. Hence, these nanoparticles could be employed as excellent adjuvant therapeutics while treating solid tumors with multi-drug resistance.

  16. pACC1 peptide loaded chitosan nanoparticles induces apoptosis via reduced fatty acid synthesis in MDA-MB-231 cells

    NASA Astrophysics Data System (ADS)

    Kaliaperumal, Jagatheesh; Hari, Natarajan; Pavankumar, Padarthi; Elangovan, Namasivayam

    2016-06-01

    The development of formulations with therapeutic peptides has been restricted to poor cell penetration and in this attempt; we developed pACC1 peptide loaded chitosan nanoparticles. The prepared nanoparticles were characterized with FT-IR, XRD, SEM and TEM. In addition, the suitable formulation was evaluated for hemocompatibility, plasma stability and embryo toxicity using Danio rerio embryo model. The results showed that pACC1 peptide loaded chitosan nanoparticles were compatible with plasma. They possess sustained release pattern and also found to be safe up to 300 mg/L in embryo toxicity tests. Cytotoxicity assays with MDA-MB-231 cell lines suggested that, pACC1 peptide loaded chitosan nanoparticles were capable of enhanced cellular penetration and reduced palmitic acid content, which was confirmed by H1 NMR. Hence, these nanoparticles could be employed as excellent adjuvant therapeutics while treating solid tumors with multi-drug resistance.

  17. Removal of Acid Orange 7 from aqueous solution using magnetic graphene/chitosan: a promising nano-adsorbent.

    PubMed

    Sheshmani, Shabnam; Ashori, Alireza; Hasanzadeh, Saeed

    2014-07-01

    Magnetic graphene/chitosan (MGCh) nanocomposite was fabricated through a facile chemical route and its application as a new adsorbent for Acid Orange 7 (AO7) removal was also investigated. After synthesis, the full characterization with various techniques (FTIR, XRD, VSM, and SEM) was achieved revealing many possible interactions/forces of dye-composite system. The results showed that, benefiting from the surface property of graphene oxide, the abundant amino and hydroxyl functional groups of chitosan, and from the magnetic property of Fe3O4, the adsorbent possesses quite a good and versatile adsorption capacity to the dye under investigation, and can be easily and rapidly extracted from water by magnetic attraction. The maximum absorption capacity was reached at initial pH 3 and 120min contact time. The batch adsorption experiments showed that the adsorption of the AO7 is considerably dependent on pH of milieu, amount of adsorbent, and contact time. The adsorption kinetics and isotherms were investigated to indicate that the kinetic and equilibrium adsorption were well-described by pseudo-first order kinetic and Langmuir isotherm model, respectively. The adsorption behavior suggested that the adsorbent surface was homogeneous in nature. The study suggests that the MGCh is a promising nano adsorbent for removal of anionic azo dyes from aqueous solution. PMID:24813679

  18. Water-soluble N-[(2-hydroxy-3-trimethylammonium)propyl]chitosan chloride as a nucleic acids vector for cell transfection.

    PubMed

    Faizuloev, Evgeny; Marova, Anna; Nikonova, Alexandra; Volkova, Irina; Gorshkova, Marina; Izumrudov, Vladimir

    2012-08-01

    To endow the cationic polysaccharides with solubility in the whole pH-range without loss of functionality of the amino groups, different chitosan samples were treated with glycidyltrimethylammonium chloride. Each modified unit of the exhaustively alkylated quaternized chitosan (QCht) contained both quaternary and secondary amino groups. The intercalated dye displacement assay and ζ-potential measurements implied stability of QCht polyplexes at physiological conditions and protonation of the secondary amino groups in slightly acidic media which is favorable for transfection according to proton sponge mechanism. The cytotoxicity and transfection efficacy increased with the chain lengthening. Nevertheless, the longest chains of QCht, 250 kDa were less toxic than PEI for COS-1 cells and revealed comparable and even significantly higher transfection activity of siRNA and plasmid DNA, respectively. Thus, highly polymerized QCht (250 kDa) provided the highest level of the plasmid DNA transfection being 5 and 80 times more active than QCht (100 kDa) and QCht (50 kDa), respectively, and 4-fold more effective than PEI, 25 kDa. The established influence of QCht molecular weight on toxicity and transfection efficacy allows elaborating polysaccharide vectors that possess rational balance of these characteristics. PMID:24750918

  19. Surface functionalization of styrenic block copolymer elastomeric biomaterials with hyaluronic acid via a "grafting to" strategy.

    PubMed

    Li, Xiaomeng; Luan, Shifang; Yuan, Shuaishuai; Song, Lingjie; Zhao, Jie; Ma, Jiao; Shi, Hengchong; Yang, Huawei; Jin, Jing; Yin, Jinghua

    2013-12-01

    As a biostable elastomer, the hydrophobicity of styrenic block copolymer (SBC) intensely limits its biomedical applications. In order to overcome such shortcoming, the SBC films were grafted with hyaluronic acid (HA) using a coupling agent. The surface chemistry of the modified films was examined by ATR-FTIR and XPS techniques, and the surface morphology was visually described by AFM. The biological performances of the HA-modified films were evaluated by a series of experiments, such as protein adsorption, platelet adhesion, and in vitro cytocompatibility. It was found that the HA-modified samples showed a low adhesiveness to fibroblast at the initial stage; however, it stimulated the growth of fibroblast. The L929 fibroblast growth presented a strong dependence on the molecular weight (MW) of HA. The samples modified with 17kDa HA exhibited the worst wettability and platelet adhesion, while providing the best results of supporting fibroblast proliferation. PMID:23974002

  20. Hyaluronic acid grafting mitigates calcification of glutaraldehyde-fixed bovine pericardium.

    PubMed

    Ohri, Rachit; Hahn, Sei K; Hoffman, Allan S; Stayton, Patrick S; Giachelli, Cecilia M

    2004-08-01

    Pathologic calcification is the leading cause of the clinical failure of glutaraldehyde-fixed bovine pericardium used in bioprosthetic valves. A novel surface modification of glutaraldehyde fixed bovine pericardium was carried out with high molecular weight hyaluronic acid (HA). HA was chemically modified with adipic dihydrazide (ADH) to introduce hydrazide functional groups onto the HA backbone. Glutaraldehyde-fixed bovine pericardium (GFBP) was modified by grafting this HA to the free aldehyde groups on the tissue via the hydrazide groups. Following a 2-week subcutaneous implantation in osteopontin (OPN)-null mice, the calcification of HA-modified bovine pericardium was drastically reduced (by 84.5%) compared to positive controls (tissue without HA-modification) (p = 0.005). The calcification-mitigating effect of HA surface modification was also confirmed by microscopic analysis of explanted tissue stained with Alizarin Red S for calcium. PMID:15227678

  1. Hyaluronic acid grafted PLGA copolymer nanoparticles enhance the targeted delivery of Bromelain in Ehrlich's Ascites Carcinoma.

    PubMed

    Bhatnagar, Priyanka; Pant, Aditya Bhushan; Shukla, Yogeshwer; Panda, Amulya; Gupta, Kailash Chand

    2016-08-01

    Rapidly increasing malignant neoplastic disease demands immediate attention. Several dietary compounds have recently emerged as strong anti-cancerous agents. Among, Bromelain (BL), a protease from pineapple plant, was used to enhance its anti-cancerous efficacy using nanotechnology. In lieu of this, hyaluronic acid (HA) grafted PLGA copolymer, having tumor targeting ability, was developed. BL was encapsulated in copolymer to obtain BL-copolymer nanoparticles (NPs) that ranged between 140 to 281nm in size. NPs exhibited higher cellular uptake and cytotoxicity in cells with high CD44 expression as compared with non-targeted NPs. In vivo results on tumor bearing mice showed that NPs were efficient in suppressing the tumor growth. Hence, the formulation could be used as a self-targeting drug delivery cargo for the remission of cancer. PMID:27287553

  2. Properties of amylose-oleic acid inclusion complexes from corn starch grafted with poly(methyl acrylate)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn starch granules have been previously investigated as fillers in polymers. In this study, much smaller particles in the form of spherulites produced by steam jet-cooking high-amylose corn starch and oleic acid to form amylose inclusion complexes were graft polymerized with methyl acrylate, both ...

  3. Properties of Starch-Poly(acrylamide-co-2-acrylamido-2-methylpropanesulfonic acid) Graft Copolymers Prepared by Reactive Extrusion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Graft copolymers of starch with acrylamide and 2-acrylamido-2-methylpropanesulfonic acid (AMPS) were prepared by reactive extrusion in a twin-screw extruder. The weight ratio of total monomer to starch was fixed at 1:3, while the molar fraction of AMPS in the monomer feed ranged from 0 to 0.119. Mon...

  4. Preparation of starch-poly-glutamic acid graft copolymers by microwave irradiation and the characterization of their properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Graft copolymers of waxy maize starch and poly-y-glutamic acid (PGA) were produced in an aqueous solution using microwave irradiation. The microwave reaction conditions were optimized with regard to temperature and pH. The temperature of 180 deg C and pH 7.0 were the best reaction conditions resulti...

  5. Antibacterial poly(lactic acid) (PLA) films grafting electrospun PLA/Ally isothioscyanate (AITC) fibers for food packaging

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Poly(lactic acid) (PLA) fibers of submicron sizes encapsulating allyl isothiocyanate (AITC) (PfA) were made and electrospun onto the surfaces of PLA films (PfA-g-film). SEM examination confirmed that the fibers were grafted to the PLA film after the (PfA-g-film) underwent air blowing and water washi...

  6. Preparation and evaluation of SiO2-deposited stearic acid-g-chitosan nanoparticles for doxorubicin delivery

    PubMed Central

    Yuan, Hong; Bao, Xin; Du, Yong-Zhong; You, Jian; Hu, Fu-Qiang

    2012-01-01

    Purpose: Both polymer micelles and mesoporous silica nanoparticles have been widely researched as vectors for small molecular insoluble drugs. To combine the advantages of copolymers and silica, studies on the preparation of copolymer-silica composites and cellular evaluation were carried out. Methods: First, a stearic acid-g-chitosan (CS-SA) copolymer was synthesized through a coupling reaction, and then silicone oxide (SiO2)-deposited doxorubicin (DOX)-loaded stearic acid-g-chitosan (CS-SA/SiO2/DOX) nanoparticles were prepared through the sol-gel reaction. Physical and chemical properties such as particle size, zeta potential, and morphologies were examined, and small-angle X-ray scattering (SAXS) analysis was employed to identify the mesoporous structures of the generated nanoparticles. Cellular uptake and cytotoxicity studies were also conducted. Results: CS-SA/SiO2/DOX nanoparticles with different amounts of SiO2 deposited were obtained, and SAXS studies showed that mesoporous structures existed in the CS-SA/SiO2/DOX nanoparticles. The mesoporous size of middle-ratio and high-ratio deposited CS-SA/SiO2/DOX nanoparticles were 4–5 nm and 8–10 nm, respectively. Based on transmission electron microscopy images of CS-SA/SiO2/DOX nanoparticles, dark rings around the nanoparticles could be observed in contrast with CS-SA/DOX micelles. Furthermore, CS-SA/SiO2/DOX nanoparticles exhibited faster release behavior in vitro than CS-SA/DOX micelles; cellular uptake research in A549 indicated that the CS-SA/SiO2/DOX nanoparticles were taken up by A549 cells more rapidly, and that CS-SA/SiO2/DOX nanoparticles entered the cell more easily when the amount of SiO2 was higher. IC50 values of CS-SA/DOX micelles, CS-SA/SiO2/DOX-4, CS-SA/SiO2/DOX-8, and CS-SA/SiO2/DOX-16 nanoparticles against A549 cells measured using the MTT assay were 1.69, 0.93, 0.32, and 0.12 μg/mL, respectively. Conclusion: SiO2-deposited stearic acid-g-chitosan organic–inorganic composites show promise

  7. Electron paramagnetic resonance study of hydrogen peroxide/ascorbic acid ratio as initiator redox pair in the inulin-gallic acid molecular grafting reaction.

    PubMed

    Arizmendi-Cotero, Daniel; Gómez-Espinosa, Rosa María; Dublán García, Octavio; Gómez-Vidales, Virginia; Dominguez-Lopez, Aurelio

    2016-01-20

    Gallic acid (GA) was grafted onto inulin using the free radicals method, generated by the hydrogen peroxide/ascorbic acid (H2O2/AA) redox pair. Molar ratios of H2O2/AA at 9, 20, 39 and 49 were evaluated by Electron Paramagnetic Resonance in order to find the effect of the oxidation of the inulin and the efficiency in the inulin-gallic acid grafting (IGA). The highest concentration of the inulin macro-radical was obtained with H2O2/AA molar ratios of 20 and 49 with the removal of a hydrogen atom from a methyl group of the inulin fructose monomers. The highest grafting ratio (30.4 mg GA eq/g IGA) was obtained at 9 M of H2O2/AA. UV-Vis, FT-IR-ATR and XDR results confirmed a successful IGA grafting. The efficiency of the grafting reaction depends on the concentration of the macro-radical, it depends on the molar ratio of H2O2/AA, being affected by simultaneous reactions between components of the mixture (H2O2, AA, inulin, GA and eventually atmospheric oxygen) as well. PMID:26572365

  8. Building, characterising and catalytic activity testing of Co-C-protected amino acid complexes covalently grafted onto chloropropylated silica gel

    NASA Astrophysics Data System (ADS)

    Varga, G.; Timár, Z.; Csendes, Z.; Bajnóczi, É. G.; Carlson, S.; Canton, S. E.; Bagi, L.; Sipos, P.; Pálinkó, I.

    2015-06-01

    Co-C-protected amino acid (C-protected L-histidine, L-tyrosine, L-cysteine and L-cystine) complexes were covalently grafted onto chloropropylated silica gel, and the materials thus obtained were structurally characterised by mid/far IR and X-ray absorption spectroscopies. The superoxide dismutase-like activities of the substances were determined via the Beauchamp-Fridovich test reaction. It was found that covalent grafting and the preparation of the anchored complexes were successful in most cases. The coordinating groups varied upon changing the conditions of the syntheses. All materials displayed catalytic activity, although catalytic activities differed widely.

  9. Preparation and Acid Catalytic Activity of TiO2 Grafted Silica MCM-41 with Sulfate Treatment

    NASA Astrophysics Data System (ADS)

    Guo, Dai-shi; Ma, Zi-feng; Yin, Chun-sheng; Jiang, Qi-zhong

    2008-02-01

    TiO2 grafted silica MCM-41 catalyst with and without sulfate treatment were prepared. The structural and acid properties of these materials were investigated by XRD, N2 adsorption-desorption, element analysis, thermal analysis, Raman and FTIR measurements. Their acid-catalytic activities were evaluated using the cyclization reaction of pseudoionone. It was found that the obtained materials possess well-ordered mesostructure, and the grafted TiO2 components were in highly dispersed amorphous form. T/MCM41 without sulfation contained only Lewis acid sites, while Brønsted and Lewis acidities were remarkably improved for the sulfated materials ST/MCM41 and d-ST/MCM41. T/MCM-41 was not active for the cyclization reaction of pseudoionone, but ST/MCM-41 and d-ST/MCM-41 possessed favorable catalytic activities. The catalytic performance of ST/MCM-41 was comparable with that of the commercial solid acid catalyst of Amberlyst-15, and better than that of d-ST/MCM-41, although the latter underwent a second TiO2 grafting process and accordingly had higher Ti and S content. The specific surface structure of Si-O-Ti-O-S=O in ST/MCM-41 and the bilateral induction effect of Si and S=O on Si-O-Ti bonds were speculated to account for its higher acid catalytic activity.

  10. Construction of antibacterial poly(ethylene terephthalate) films via layer by layer assembly of chitosan and hyaluronic acid.

    PubMed

    Del Hoyo-Gallego, Sara; Pérez-Álvarez, Leyre; Gómez-Galván, Flor; Lizundia, Erlantz; Kuritka, Ivo; Sedlarik, Vladimir; Laza, Jose Manuel; Vila-Vilela, Jose Luis

    2016-06-01

    Polyelectrolytic multilayers (PEMs) with enhanced antibacterial properties were built up onto commercial poly(ethylene terephthalate) (PET) films based on the layer by layer assembling of bacterial contact killing chitosan and bacterial repelling highly hydrated hyaluronic acid. The optimization of the aminolysis modification reaction of PET was carried out by the study of the mechanical properties and the surface characterization of the modified polymers. The layer by layer assembly was successfully monitored by TEM microscopy, surface zeta-potential, contact angle measurements and, after labeling with fluorescein isothiocyanate (FTIC) by absorption spectroscopy and confocal fluorescent microscopy. Beside, the stability of the PEMs was studied at physiological conditions in absence and in the presence of lysozyme and hyaluronidase enzymes. Antibacterial properties of the obtained PEMs against Escherichia coli were compared with original commercial PET. PMID:27083341

  11. Kinetics of sorption of Cu(II)-ethylenediaminetetraacetic acid chelated anions on cross-linked, polyaminated chitosan beads

    SciTech Connect

    Juang, R.S.; Ju, C.Y.

    1998-08-01

    Rates of sorption of Cu(II)-ethylenediaminetetraacetic acid (EDTA) chelated anions from aqueous solutions on cross-linked, poly(ethylenimine) (PEI)-modified chitosan beads were measured in a batch stirred vessel. All experiments were carried out in an equimolar solution of Cu(II) and EDTA (0.47--3.15 mol/m{sup 3}). It was shown that the rates of sorption increased with an increase in the initial concentration of Cu(II), pH, and temperature but decreased with an increase in the molecular weight of PEI introduced in the beads. The widely used homogeneous diffusion model based on Fick`s law and the shrinking core model cannot describe the sorption process. On the contrary, the kinetic data were well fit by the Elovich equation. The apparent activation energies evaluated (3.5--8.4 kcal/mol at pH 3) indicated the combined film and particle diffusion mechanism.

  12. Characterization and anticancer potential of ferulic acid-loaded chitosan nanoparticles against ME-180 human cervical cancer cell lines

    NASA Astrophysics Data System (ADS)

    Panwar, Richa; Sharma, Asvene K.; Kaloti, Mandeep; Dutt, Dharm; Pruthi, Vikas

    2016-08-01

    Ferulic acid (FA) is a widely distributed hydroxycinnamic acid found in various cereals and fruits exhibiting potent antioxidant and anticancer activities. However, due to low solubility and permeability, its availability to biological systems is limited. Non-toxic chitosan-tripolyphosphate pentasodium (CS-TPP) nanoparticles (NPs) are used to load sparingly soluble molecules and drugs, increasing their bioavailability. In the present work, we have encapsulated FA into the CS-TPP NPs to increase its potential as a therapeutic agent. Different concentrations of FA were tested to obtain optimum sized FA-loaded CS-TPP nanoparticles (FA/CS-TPP NPs) by ionic gelation method. Nanoparticles were characterized by scanning electron microscopy, Fourier transformation infrared spectroscopy (FTIR), thermogravimetric analyses and evaluated for their anticancer activity against ME-180 human cervical cancer cell lines. The FTIR spectra confirmed the encapsulation of FA and thermal analysis depicted its degradation profile. A concentration-dependent relationship between FA encapsulation efficiency and FA/CS-TPP NPs diameter was observed. Smooth and spherical FA-loaded cytocompatible nanoparticles with an average diameter of 125 nm were obtained at 40 µM FA conc. The cytotoxicity of 40 µM FA/CS-TPP NPs against ME-180 cervical cancer cell lines was found to be higher as compared to 40 µM native FA. Apoptotic morphological changes as cytoplasmic remnants and damaged wrinkled cells in ME-180 cells were visualized using scanning electron microscopic and fluorescent microscopic techniques. Data concluded that chitosan enveloped FA nanoparticles could be exploited as an excellent therapeutic drug against cancer cells proliferation.

  13. Characterization and anticancer potential of ferulic acid-loaded chitosan nanoparticles against ME-180 human cervical cancer cell lines

    NASA Astrophysics Data System (ADS)

    Panwar, Richa; Sharma, Asvene K.; Kaloti, Mandeep; Dutt, Dharm; Pruthi, Vikas

    2015-10-01

    Ferulic acid (FA) is a widely distributed hydroxycinnamic acid found in various cereals and fruits exhibiting potent antioxidant and anticancer activities. However, due to low solubility and permeability, its availability to biological systems is limited. Non-toxic chitosan-tripolyphosphate pentasodium (CS-TPP) nanoparticles (NPs) are used to load sparingly soluble molecules and drugs, increasing their bioavailability. In the present work, we have encapsulated FA into the CS-TPP NPs to increase its potential as a therapeutic agent. Different concentrations of FA were tested to obtain optimum sized FA-loaded CS-TPP nanoparticles (FA/CS-TPP NPs) by ionic gelation method. Nanoparticles were characterized by scanning electron microscopy, Fourier transformation infrared spectroscopy (FTIR), thermogravimetric analyses and evaluated for their anticancer activity against ME-180 human cervical cancer cell lines. The FTIR spectra confirmed the encapsulation of FA and thermal analysis depicted its degradation profile. A concentration-dependent relationship between FA encapsulation efficiency and FA/CS-TPP NPs diameter was observed. Smooth and spherical FA-loaded cytocompatible nanoparticles with an average diameter of 125 nm were obtained at 40 µM FA conc. The cytotoxicity of 40 µM FA/CS-TPP NPs against ME-180 cervical cancer cell lines was found to be higher as compared to 40 µM native FA. Apoptotic morphological changes as cytoplasmic remnants and damaged wrinkled cells in ME-180 cells were visualized using scanning electron microscopic and fluorescent microscopic techniques. Data concluded that chitosan enveloped FA nanoparticles could be exploited as an excellent therapeutic drug against cancer cells proliferation.

  14. Synthesis of perm-selective membranes by grafting acrylic acid into air-irradiated Teflon-FEP films

    NASA Astrophysics Data System (ADS)

    Bozzi, Annick; Chapiro, Adolphe

    Grafting acrylic acid into air-irradiated Teflon-FEP films was investigated. Pre-irradiation doses ranged from 0.5 to 10 kGy. Grafting occurred at 45 or 60°C. Homopolymerization inhibitors, ferrous ions or methylene blue, were added to the system. It was found that after completion of the reaction, within 40-100 min, membranes were obtained with very low electric resistivities. The influence of added inhibitors, pre-irradiation dose and grafting temperature was studied. From the results it is concluded that the initiating centers in air-irradiated Teflon-FEP are, on the one hand, peroxides of structure POOP', in which P is a polymeric radical and Pprime; a small fragment, and on the other trapped PO .2 radicals. The latter only react after losing their oxygen. In the presence of polymerization inhibitors, initiation involves a redox process which reduces the overall activation energy.

  15. Preparation of thermosensitive membranes by radiation grafting of acrylic acid/ N-isopropyl acrylamide binary mixture on PET fabric

    NASA Astrophysics Data System (ADS)

    Gupta, Bhuvanesh; Mishra, Swaiti; Saxena, Shalini

    2008-05-01

    Thermosensitive membranes were prepared by radiation-induced graft copolymerization of monomers on PET fabrics. A binary mixture of N-isopropyl acrylamide (NIPAAm) and acrylic acid (AA) was grafted on polyester fabric as a base material to introduce thermosensitive poly( N-isopropyl acrylamide) pendant chains having LCST slightly higher than 37 °C in the membrane. The influence of ferrous sulfate, radiation dose and monomer composition on the degree of grafting was studied. The structure of the grafted fabric was characterized by thermogravimetric analysis, differential scanning calorimetry and scanning electron microscopy. The thermosensitive nature of the fabric was monitored by swelling at different temperatures. The graft copolymerization of AA with NIPAAm enhanced the LCST of the resultant membrane to ˜37 °C. The moisture vapor transmission rate (MVTR) and air permeability of the fabric decreased slightly, may be due to the slight blocking of the fabric pores. The immobilization of tetracycline hydrochloride as the model drug and its release characteristics at different temperatures were monitored.

  16. Enhancing antibiofouling performance of Polysulfone (PSf) membrane by photo-grafting of capsaicin derivative and acrylic acid

    NASA Astrophysics Data System (ADS)

    Wang, Jian; Sun, Haijing; Gao, Xueli; Gao, Congjie

    2014-10-01

    Biofouling is a critical issue in membrane water and wastewater treatment. Herein, antibiofouling PSf membrane was prepared by UV-assisted graft polymerization of acrylic acid (AA) and a capsaicin derivative, N-(5-methyl-3-tert-butyl-2-hydroxy benzyl) acrylamide (MBHBA), on PSf membrane. AA and MBHBA were used as hydrophilic monomer and antibacterial monomer separately. The membranes were characterized by FTIR-ATR, contact angle, SEM, AFM, cross-flow filtration unit, antifouling and antibacterial measurements. Verification of MBHBA and AA that photo-chemically grafted onto the PSf membrane surface is confirmed by carbonyl stretching vibration at ∼1655 cm-1 and ∼1730 cm-1, separately. The increasing AA concentration accelerates the graft-polymerization of MBHBA and resulted in a more hydrophilic surface. Consequently, antifouling property of the membranes was improved on a large level. The flux recovery rate can achieve 100% during the cyclic test, which may be attributed to the more hydrophilic and smooth surface, as well as the decreased membrane pore size. Most importantly, the presence of AA in graft co-polymer does not affect the antibacterial activity of MBHBA. That may be induced by the increasing chain length and flexibility of the grafted polymer chains.

  17. Oral delivery of shRNA based on amino acid modified chitosan for improved antitumor efficacy.

    PubMed

    Zheng, Hao; Tang, Cui; Yin, Chunhua

    2015-11-01

    In this investigation, chitosan-histidine-cysteine (CHC) was engineered for oral delivery of Survivin short hairpin RNA (shRNA)-expressing plasmid DNA (shSur-pDNA) to promote hepatoma regression through integrating the advantages of histidine and cysteine to conquer serial cellular and systemic barriers. CHC could effectively encapsulate shSur-pDNA to form compact nanocomplexes (NC) at adequate weight ratios. Sequential modification with histidine and cysteine conferred CHC NC with the beneficial attributes for shRNA delivery including improved stability, facilitated internalization, promoted endosomal escape, increased nuclear localization, and GSH-responsive release, which contributed to their superior performance in terms of apoptosis promotion, proliferation inhibition, and Survivin down-regulation of tumor cells. More importantly, in hepatoma-bearing mice, orally delivered CHC NC overweighed chitosan counterparts with respect to suppressed Survivin expression, retarded tumor growth, and prolonged surviving time, owing to their above-mentioned merits in combination with enhanced intestinal permeation. Especially, rapid intracellular release of CHC NC with lower molecular weight of 30 kDa (CHC30 NC) might be responsible for the most satisfactory antitumor efficacy with tumor inhibition ratio (TIR) of 92.5%, which rendered CHC30 NC a promising vehicle for oral delivery of shRNA. This investigation would shed light on the deliberate design of oral shRNA delivery vehicles to mediate effective antitumor efficacy. PMID:26310108

  18. Development and characterization of an LDPE/chitosan composite antimicrobial film for chilled fish storage.

    PubMed

    Reesha, K V; Panda, Satyen Kumar; Bindu, J; Varghese, T O

    2015-08-01

    An antimicrobial packaging material was developed by uniformly embedding 1, 3 and 5% chitosan (w/w) in low density polyethylene matrix using maleic anhydride grafted LDPE as a compatible agent. The materials were mixed by compounding and blown into monolayer films via blown film extrusion. The developed films showed good barrier properties against oxygen. Characterization of the composite films with Fourier transform infrared spectroscopy revealed that chitosan and LDPE interacted well with each other. Overall migration showed better release of chitosan adduct from the LDPE matrix which enhanced the antibacterial properties of the films. The interaction between the LDPE/CS and maleic anhydride grafted LDPE had a decreasing effect on the tensile strength and heat sealing properties. Investigation on antimicrobial properties of LDPE/CS films showed 85-100% inhibition of Escherichia coli. Efficacy of LDPE/CS films was evaluated by using them as packaging material for chilled storage of Tilapia (Oreochromis mossambicus). Analysis of storage quality indices (peroxide value, free fatty acid, total volatile base nitrogen and aerobic plate count) revealed good antibacterial property and extension of shelf life of Tilapia in the chitosan incorporated novel composite films compared to virgin LDPE film. PMID:26092060

  19. The role of glycyrrhetinic acid modification on preparation and evaluation of quercetin-loaded chitosan-based self-aggregates.

    PubMed

    Du, Hongliang; Liu, Mengrui; Yang, Xiaoye; Zhai, Guangxi

    2015-12-15

    Quercetin (QC), a type of plant-based chemical, has been reported to own anticancer activity in vivo. However, the poor water solubility limits its pharmaceutical application. In this study, two kinds of QC-loaded self-aggregates based on O-carboxymethyl chitosan-cholic acid conjugates (CMCA) were developed to improve the drug bioavailability in which glycyrrhetinic acid (GA) modification was utilized in the nanocarrier fabrication (QC-GA-CMCA) or not (QC-CMCA). These self-aggregates were prepared by a modified ultrasound-dialysis method and the role of GA modification on the evaluation of QC-loaded self-aggregates was investigated. Transmission Electron Microscopy (TEM) images revealed the formation of spherical particles of both self-aggregates. Dynamic Light Scattering (DLS) analysis and UV-VIS spectroscopy showed that the QC-GA-CMCA had smaller size, narrower size distribution, higher drug loading and entrapment efficiency than corresponding QC-CMCA aggregates. QC-GA-CMCA showed more obvious sensitivity to acidic pH condition based on the zeta potential measurements at various pHs, and fastest drug release was observed at pH 5.7 for QC-CMCA while at pH 6.5 for QC-GA-CMCA. In addition, QC-GA-CMCA demonstrated enhanced cell cytotoxicity and higher cell apoptosis rate in vitro, and also higher AUC value and a prolonged residence time of drug in vivo. PMID:26319324

  20. Rheological Properties of Aqueous Acid Solutions of Chitosan: Experiment and Calculations of the Viscometric Functions on the Basis of a Mesoscopic Model

    NASA Astrophysics Data System (ADS)

    Shipovskaya, A. B.; Abramov, A. Yu.; Pyshnograi, G. V.; Aziz, Al Joda Hyder Nadom

    2016-05-01

    The rheological properties of chitosan solutions in acetic acid at 20°C in the range of polymer concentrations from 0.5 to 8 mass% and acid concentrations from 2 to 70% have been investigated. With the use of a modified Vinogradov-Pokrovskii model based on the microstructural approach to the description of polymer fluid dynamics, numerical solutions of gradient dependences of viscometric functions of aqueous acid solutions of chitosan have been obtained. It has been established that the numerical solution describes with good accuracy the experimental viscosity rheograms. The values of the highest Newton viscosity ηmax have been calculated. The concentration modes of semidiluted and concentrated solutions have been determined by the dependence of ηmax on the polymer concentration, and the range of concentrations in which the mass transfer mechanism changes and a fluctuation network is formed has been found. It has been shown that the concentration of acetic acid practically does not influence the structure and character of flow of chitosan solutions, the formation concentration of a network, and the efficiency of its labile nodes.

  1. Increased neuronal survival in the brainstem during liver injury: role of γ-aminobutyric acid and serotonin chitosan nanoparticles.

    PubMed

    Shilpa, J; Anitha, M; Paulose, C S

    2013-09-01

    γ-Aminobutyric acid (GABA)- and serotonin (5-HT)-mediated cell signaling, neuronal survival enhancement, and reduced neuronal death in brainstem during liver injury followed by active liver regeneration have a critical role in maintaining routine bodily functions. In the present study, GABAB and 5-HT2A receptor functional regulation, interrelated actions of neuronal survival factors, and expression of apoptotic factors in the brainstem during GABA and 5-HT chitosan nanoparticles-induced active liver regeneration in partially hepatectomized rats were evaluated. Partially hepatectomized rats were treated with the nanoparticles, and receptor assays and confocal microscopic studies of GABAB and 5-HT2A receptors, gene expression studies of GABAB and 5-HT2A receptors, nuclear factor-κB (NF-κB), tumor necrosis factor-α (TNF-α), Akt-1, phospholipase C, Bax, and caspase-8 were performed with the brainstems of experimental animals. A significant decrease in GABAB and 5-HT2A receptor numbers and gene expressions denoted a homeostatic adjustment by the brain to trigger the sympathetic innervations during elevated DNA synthesis in the liver. The neuronal apoptosis resulting from the loss of liver function after partial hepatectomy was minimized by nanoparticle treatment in rats compared with rats with no treatment during regeneration. This was confirmed from the gene expression patterns of NF-κB, TNF-α, Akt-1, phospholipase C, Bax, and caspase-8. The present study revealed the potential of GABA and 5-HT chitosan nanoparticles for increasing neuronal survival in the brainstem during liver injury following regeneration, which avoids many neuropsychiatric problems. PMID:23861071

  2. Boric acid-mediated B,N-codoped chitosan-derived porous carbons with a high surface area and greatly improved supercapacitor performance

    NASA Astrophysics Data System (ADS)

    Ling, Zheng; Wang, Gang; Zhang, Mengdi; Fan, Xiaoming; Yu, Chang; Yang, Juan; Xiao, Nan; Qiu, Jieshan

    2015-03-01

    This work reports an efficient strategy to synthesize B,N-codoped porous carbons with a high specific surface area using chitosan as the carbon precursor with the help of boric acid, featuring a high specific capacitance, large operation voltage and excellent cycle stability for supercapacitors.This work reports an efficient strategy to synthesize B,N-codoped porous carbons with a high specific surface area using chitosan as the carbon precursor with the help of boric acid, featuring a high specific capacitance, large operation voltage and excellent cycle stability for supercapacitors. Electronic supplementary information (ESI) available: Experimental details, additional figures and tables see DOI: 10.1039/c5nr00081e

  3. Carboxy terminated rubber based on natural rubber grafted with acid anhydrides and its adhesion properties

    NASA Astrophysics Data System (ADS)

    Klinpituksa, P.; Kongkalai, P.; Kaesaman, A.

    2014-08-01

    The chemical modification of natural rubber by grafting of various polar functional molecules is an essential method, improving the versatility of rubber in applications. This research investigated the preparation of natural rubber-graft-citraconic anhydride (NR-g-CCA), natural rubber-graft-itaconic anhydride (NR-g-ICA), and natural rubber-graft-maleic anhydride (NR-g-MA), with the anhydrides grafted to natural rubber in toluene using benzoyl peroxide as an initiator. Variations of monomer content, initiator content, temperature and reaction time of the grafting copolymerization were investigated. The maximum degrees of grafting were 1.06% for NR-g-CCA, 4.66% for NR-g-ICA, and 5.03% for NR-g-MA, reached using 10 phr citraconic anhydride, 10 phr of itaconic anhydride, or 8 phr of maleic anhydride, 3 phr benzoyl peroxide, at 85, 80 and 80°C for 2, 2 and 3 hrs, respectively. Solvent-based wood adhesives were formulated from these copolymers with various contents of wood resin in the range 10-40 phr. The maximal 289 N/in cleavage peel and 245.7 KPa shear strength for NR-g-MA (5.03% grafting) were obtained at 40 phr wood resin.

  4. Enhanced Photocatalytic Degradation of Salicylic Acid in Water-ethanol Mixtures from Titanium Dioxide Grafted with Hexadecyltrichlorosilane

    NASA Astrophysics Data System (ADS)

    Kassir, Mounir; Roques-Carmes, Thibault; Assaker, Karine; Hamieh, Tayssir; Razafitianamaharavo, Angelina; Toufaily, Joumana; Villiéras, Frédéric

    The aim of this paper is to study the effect of the chemical modification on the photocatalytic properties of TiO2. The TiO2 Degussa-P25 nanoparticles are chemically modified using the hydrophobic organosilane hexadecyltrichlorosilane (HTS). The samples are employed as catalysts for salicylic acid photocatalytic oxidation in water-ethanol mixtures. The kinetics of salicylic acid photodegradation is investigated as a function of ethanol content in water-ethanol mixtures and initial HTS concentrations. The results indicate that the HTS groups are not degraded during the photocatalytic process. The TiO2 grafted by HTS is more efficient than bare TiO2 for the photodegradation process in presence of ethanol. The photodegradation process follows first order kinetics and the apparent rate constant increases linearly with the initial HTS concentration (amount of HTS grafted).

  5. A chitosan coated monolith for nucleic acid capture in a thermoplastic microfluidic chip

    PubMed Central

    Kendall, Eric L.; Wienhold, Erik; DeVoe, Don L.

    2014-01-01

    A technique for microfluidic, pH modulated DNA capture and purification using chitosan functionalized glycidyl methacrylate monoliths is presented. Highly porous polymer monoliths are formed and subsequently functionalized off-chip in a batch process before insertion into thermoplastic microchannels prior to solvent bonding, simplifying the overall fabrication process by eliminating the need for on-chip surface modifications. The monolith anchoring method allows for the use of large cross-section monoliths enabling high flowrates and high DNA capture capacity with a minimum of added design complexity. Using monolith capture elements requiring less than 1 mm2 of chip surface area, loading levels above 100 ng are demonstrated, with DNA capture and elution efficiency of 54.2% ± 14.2% achieved. PMID:25379094

  6. Effect of aniline on cadmium adsorption by sulfanilic acid-grafted magnetic graphene oxide sheets.

    PubMed

    Hu, Xin-jiang; Liu, Yun-guo; Zeng, Guang-ming; Wang, Hui; Hu, Xi; Chen, An-wei; Wang, Ya-qin; Guo, Yi-Mming; Li, Ting-ting; Zhou, Lu; Liu, Shao-heng; Zeng, Xiao-xia

    2014-07-15

    Cd(II) has posed severe health risks worldwide. To remove this contaminant from aqueous solution, the sulfanilic acid-grafted magnetic graphene oxide sheets (MGOs/SA) were prepared and characterized. The mutual effects of Cd(II) and aniline adsorption on MGOs/SA were studied. The effects of operating parameters such as pH, ionic strength, contact time and temperature on the Cd(II) enrichment, as well as the adsorption kinetics and isotherm were also investigated. The results demonstrated that MGOs/SA could effectively remove Cd(II) and aniline from the aqueous solution and the two adsorption processes were strongly dependent on solution pH. The Cd(II) adsorption was reduced by the presence of aniline at pH<5.4 but was improved at pH>5.4. The presence of Cd(II) diminished the adsorption capacity for aniline at pH<7.8 but enhanced the aniline adsorption at pH>7.8. The decontamination of Cd(II) by MGOs/SA was influenced by ionic strength. Besides, the adsorption process could be well described by pseudo-second-order kinetic model. The intraparticle diffusion study revealed that the intraparticle diffusion was not the only rate-limiting step for the adsorption process. Moreover, the experimental data of isotherm followed the Freundlich isotherm model. PMID:24863786

  7. Linolenic acid grafted hyaluronan: Process development, structural characterization, biological assessing, and stability studies.

    PubMed

    Huerta-Angeles, Gloria; Brandejsová, Martina; Kulhánek, Jaromír; Pavlík, Vojtěch; Šmejkalová, Daniela; Vágnerová, Hana; Velebný, Vladimír

    2016-11-01

    In this study, hyaluronan (HA) was grafted with alpha-linolenic acid (αLNA) by benzoyl mixed anhydrides methodology, which allowed the derivatization of HA under mild reaction conditions. The reaction was optimized and transferred from laboratory to semi-scale production. The derivative revealed an unexpected cytotoxicity after oven drying and storage at 40°C. For this reason, the storage conditions of sodium linolenyl hyaluronate (αLNA-HA) were optimized in order to preserve the beneficial effect of the derivative. Oven, spray dried and lyophilized samples were prepared and stored at -20°C, 4°C and 25°C up to 6 months. A comprehensive material characterization including stability study of the derivative, as well as evaluation of possible changes on chemical structure and presence of peroxidation products were studied by Nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), gas chromatography-mass spectrometry (GC-MS), thermogravimetric analysis (TGA) and complemented with assessment of in vitro viability on mouse fibroblasts NIH-3T3. The most stable αLNA-HA derivative was obtained after spray drying and storage at ambient temperature under inert atmosphere. The choice of inert atmosphere is recommended to suppress oxidation of αLNA supporting the positive influence of the derivative on cell viability. The encapsulation of hydrophobic drugs of αLNA-HA were also demonstrated. PMID:27516333

  8. Chitosan-based mucoadhesive films containing 5-aminolevulinic acid for buccal cancer's treatment.

    PubMed

    Costa, Irina dos Santos Miranda; Abranches, Renata Pereira; Garcia, Maria Teresa Junqueira; Pierre, Maria Bernadete Riemma

    2014-11-01

    Photodynamic therapy (PDT) is a relatively new method to treat various kinds of tumors, including those of the oral cavity. The topical 5-ALA-PDT treatment for tumors of the oral mucosa is preferred, since when administered systemically, there is a general photosensitization drawback in the patient. However, 5-ALA is a hydrophilic molecule and its penetration and retention is limited by topical route, including oral mucosa. We propose a topical delivery system of chitosan-based mucoadhesive film, aiming to promote greater retention of 5-ALA in tissue. The chitosan (CHT) films (4% w/w) were prepared using the solvent evaporation/casting technique. They were tested without 5-ALA resulting in permeability to water vapor (W.V.P=2.15-8.54 g mm/(h cm(2)Pa) swelling ∼300.0% (±10.5) at 4 h or 24 h and in vitro residence time >24 h for all tests. CHT films containing 10.0% (w/w) 5-ALA have resulted in average weight of 0.22 g and thickness of 0.608 mm as suitable characteristics for oral application. In the presence of CHT films both in vitro permeation and retention of 5-ALA (1.0% or 10.0%) were increased. However, 10.0% 5-ALA presented highest values of permeation and retention (∼4 and 17 times respectively, compared to propylene glycol vehicle). On the other hand, in vitro mucoadhesion of CHT films was decreased (18.2-fold and 3.1-fold) by 5-ALA addition (1.0% or 10.0% respectively). However, CHT film containing 10.0% of 5-ALA can be a potential delivery system for topical use in the treatment of tumors of the oral cavity using PDT because it favored the retention of 5-ALA in this tissue and has shown convenient mucoadhesion. PMID:25190225

  9. Conferring high-temperature tolerance to nontransgenic tomato scions using graft transmission of RNA silencing of the fatty acid desaturase gene.

    PubMed

    Nakamura, Shinya; Hondo, Kana; Kawara, Tomoko; Okazaki, Yozo; Saito, Kazuki; Kobayashi, Kappei; Yaeno, Takashi; Yamaoka, Naoto; Nishiguchi, Masamichi

    2016-02-01

    We investigated graft transmission of high-temperature tolerance in tomato scions to nontransgenic scions from transgenic rootstocks, where the fatty acid desaturase gene (LeFAD7) was RNA-silenced. Tomato was transformed with a plasmid carrying an inverted repeat of LeFAD7 by Agrobacterium. Several transgenic lines showed the lower amounts of LeFAD7 RNA and unsaturated fatty acids, while nontransgenic control did not, and siRNA was detected in the transgenic lines, but not in control. These lines grew under conditions of high temperature, while nontransgenic control did not. Further, the nontransgenic plants were grafted onto the silenced transgenic plants. The scions showed less of the target gene RNA, and siRNA was detected. Under high-temperature conditions, these grafted plants grew, while control grafted plants did not. Thus, it was shown that high-temperature tolerance was conferred in the nontransgenic scions after grafting onto the silenced rootstocks. PMID:26132723

  10. Peripheral Nerve Regeneration Through Hydrogel-Enriched Chitosan Conduits Containing Engineered Schwann Cells for Drug Delivery.

    PubMed

    Meyer, Cora; Wrobel, Sandra; Raimondo, Stefania; Rochkind, Shimon; Heimann, Claudia; Shahar, Abraham; Ziv-Polat, Ofra; Geuna, Stefano; Grothe, Claudia; Haastert-Talini, Kirsten

    2016-01-01

    Critical length nerve defects in the rat sciatic nerve model were reconstructed with chitosan nerve guides filled with Schwann cells (SCs) containing hydrogel. The transplanted SCs were naive or had been genetically modified to overexpress neurotrophic factors, thus providing a cellular neurotrophic factor delivery system. Prior to the assessment in vivo, in vitro studies evaluating the properties of engineered SCs overexpressing glial cell line-derived neurotrophic factor (GDNF) or fibroblast growth factor 2 (FGF-2(18kDa)) demonstrated their neurite outgrowth inductive bioactivity for sympathetic PC-12 cells as well as for dissociated dorsal root ganglion cell drop cultures. SCs within NVR-hydrogel, which is mainly composed of hyaluronic acid and laminin, were delivered into the lumen of chitosan hollow conduits with a 5% degree of acetylation. The viability and neurotrophic factor production by engineered SCs within NVR-Gel inside the chitosan nerve guides was further demonstrated in vitro. In vivo we studied the outcome of peripheral nerve regeneration after reconstruction of 15-mm nerve gaps with either chitosan/NVR-Gel/SCs composite nerve guides or autologous nerve grafts (ANGs). While ANGs did guarantee for functional sensory and motor regeneration in 100% of the animals, delivery of NVR-Gel into the chitosan nerve guides obviously impaired sufficient axonal outgrowth. This obstacle was overcome to a remarkable extent when the NVR-Gel was enriched with FGF-2(18kDa) overexpressing SCs. PMID:25876520

  11. The Quality Changes of Postharvest Mulberry Fruit Treated by Chitosan-g-Caffeic Acid During Cold Storage.

    PubMed

    Yang, Caifeng; Han, Beibei; Zheng, Yu; Liu, Lili; Li, Changlong; Sheng, Sheng; Zhang, Jian; Wang, Jun; Wu, Fuan

    2016-04-01

    This study aimed to characterize the effects of chitosan-g-caffeic acid (CTS-g-CA) on improving the quality and extending the shelf life of postharvest mulberry fruit during storage at 4 °C for 18 d. CTS-g-CA was enzymatically synthesized using laccase from Pleurotus ostreatus as a catalyst. The synergistic effects of CTS-g-CA treatment on mulberry fruit were evaluated using a co-toxicity factor (cf). The results showed that the rotting rate of CTS-g-CA-treated fruit was 37.67% (compared with that of the control at 97.67%) on day 18. The weight loss and malondialdehyde (MDA) contents of the CTS-g-CA-treated mulberry fruit were significantly lower (P < 0.05) than those of the control, CA, CTS, and CA+CTS treatments. Moreover, the DPPH and ABTS radical scavenging activities of the CTS-g-CA treatment were both higher than those of the control. Furthermore, the CTS-g-CA treatment also maintained higher levels of main active substances, such as anthocyanins, ascorbic acid, polyphenols and flavones, in mulberry fruit than the other treatments. Therefore, CTS-g-CA could be used to improve the quality and extend the shelf life of postharvest mulberry fruit during cold storage. PMID:26992122

  12. Characterization of Chitosan Nanofiber Sheets for Antifungal Application

    PubMed Central

    Egusa, Mayumi; Iwamoto, Ryo; Izawa, Hironori; Morimoto, Minoru; Saimoto, Hiroyuki; Kaminaka, Hironori; Ifuku, Shinsuke

    2015-01-01

    Chitosan produced by the deacetylation of chitin is a cationic polymer with antimicrobial properties. In this study, we demonstrate the improvement of chitosan properties by nanofibrillation. Nanofiber sheets were prepared from nanofibrillated chitosan under neutral conditions. The Young’s modulus and tensile strength of the chitosan NF sheets were higher than those of the chitosan sheets prepared from dissolving chitosan in acetic acid. The chitosan NF sheets showed strong mycelial growth inhibition against dermatophytes Microsporum and Trichophyton. Moreover, the chitosan NF sheets exhibited resistance to degradation by the fungi, suggesting potentials long-lasting usage. In addition, surface-deacetylated chitin nanofiber (SDCNF) sheets were prepared. The SDCNF sheet had a high Young’s modulus and tensile strength and showed antifungal activity to dermatophytes. These data indicate that nanofibrillation improved the properties of chitosan. Thus, chitosan NF and SDCNF sheets are useful candidates for antimicrobial materials. PMID:26540046

  13. Biocompatibility and functional performance of a polyethylene glycol acid-grafted cellulosic membrane for hemodialysis.

    PubMed

    Sirolli, V; Di Stante, S; Stuard, S; Di Liberato, L; Amoroso, L; Cappelli, P; Bonomini, M

    2000-06-01

    In order to improve the biochemical reactivity of the cellulose polymer, which is mainly attributed to the presence of surface hydroxyl groups, derivatized cellulosic membranes have been engineered replacing or masking some or all of the hydroxyl groups in the manufacturing process of the membrane. The present study was set up to analyze both biocompatibility and functional performance of two different derivatized cellulosic membranes (cellulose diacetate; polyethylene glycol, PEG, acid-grafted cellulose) as compared to a synthetic membrane (polymethylmethacrylate, PMMA). Cellulose diacetate is prepared by substituting hydroxyl groups with acetyl groups; PEG cellulose is obtained by grafting PEG chains onto the cellulosic polymer with a smaller amount of substitution than cellulose diacetate. While the three dialyzers provided similar urea and creatinine removal, the dialyzer containing cellulose diacetate showed a reduced ability to remove 32-microglobulin compared to that containing PEG cellulose or PMMA. A transient reduction in leukocyte count was observed for both derivatized cellulosic membranes. The neutrophil and monocyte counts throughout the entire dialysis session showed a closer parallelism with the cellular expression of the adhesive receptor CD 15s (sialyl-Lewis x molecule) than with CD11b/CD18 expression. Platelet activation, as indicated by the percentage of cells expressing the activation markers CD62P (P-selectin) and CD63 (gp53), occurred with all membranes at 15 min of dialysis and also with PMMA at 30 min. An increased formation of platelet-neutrophil and platelet-monocyte coaggregates was found at 15 and 30 min during dialysis with cellulose diacetate and PMMA but not with PEG cellulose. Generally in concomitance with the increase in platelet-neutrophil coaggregates, an increased hydrogen peroxide production by neutrophils occurred. Our results indicate that derivatizing cellulose may represent a useful approach to improve the biocompatibility

  14. Chitosan composite films. Biomedical applications.

    PubMed

    Cárdenas, Galo; Anaya, Paola; von Plessing, Carlos; Rojas, Carlos; Sepúlveda, Jackeline

    2008-06-01

    Chitosan acetate films have been prepared using chitosans from shrimps (Pleuroncodes monodon) of low and high molecular weight (LMv = 68,000 g/mol and HMv = 232,000 g/mol) and deacetylation degree of 80 and 100%, respectively. The chitosan films were obtained by addition of several additives to acetic acid chitosan solutions, such as: glycerol, oleic acid and linoleic acid in different proportions. The pH of the solutions before casting ranged from 5.0 to 6.0. The composite film thickness are reported. The films have been analyzed by FTIR showing characteristic bands corresponding to the additives. The scanning electron microscopy (SEM) studies reveals the different morphology of the composite films. The films exhibit different physical properties depending upon the additives and/or mixture of them. The addition of glycerol to composite improves the elasticity of the films. The swelling in glucose and saline solutions for several films was evaluated, being higher in the glucose solution. The bactericide test against Staphylococcus aureus, Pseudomona aeruginosa and Acinetobacter baumanii in plates with either blood and or agar tripticase showed that the molecular weight influences on the bactericidal properties of the chitosan composite films and over its effect against gram positive and gram negative bacteria. Medical applications of the composite films were done in patients with burns, ulcers and injuries, the films containing glycerol showed good adhesion in comparison with those without it. The composite films tested were mainly three (1) chitosan acetate with glycerol, (2) chitosan acetate with oleic acid and (3) chitosan acetate with glycerol and oleic acid. Excellent results in the skin recovery were obtained after 7-10 days. Since the chitosan is biodegradable by the body enzymes it does not need to be removed and increases the gradual grows of the damage tissues. PMID:18165888

  15. Improvement of functional recovery of transected peripheral nerve by means of chitosan grafts filled with vitamin E, pyrroloquinoline quinone and their combination.

    PubMed

    Azizi, Asghar; Azizi, Saeed; Heshmatian, Behnam; Amini, Keyvan

    2014-01-01

    Effects of vitamin E and pyrroloquinoline quinone on peripheral nerve regeneration were studied using a rat sciatic nerve transection model. Ninety male healthy White Wistar rats were divided into three experimental groups (n = 15), randomly: Sham-operation (SHAM), transected control (TC), chitosan conduit (Chit) and three treatment groups (Vit E, PQQ and PQQ + Vit E). In SHAM group after anesthesia, left sciatic nerve was exposed through a gluteal muscle incision and after homeostasis muscle was sutured. In Chit group left sciatic nerve was exposed the same way and transected proximal to tibio-peroneal bifurcation leaving a 10-mm gap. Proximal and distal stumps were each inserted into a chitosan tube. In treatment groups the tube was implanted the same way and filled with Vit E, PQQ and PQQ + Vit E. Each group was subdivided into three subgroups of six animals each and were studied 4, 8, 12 weeks after surgery. Functional and electrophysiological studies, and gastrocnemius muscle mass measurement confirmed faster and better recovery of regenerated axons in Vit E + PQQ combination compared to Vit E or PQQ solely (P < 0.05). Morphometric indices of regenerated fibers showed number and diameter of the myelinated fibers in PQQ + Vit E was significantly higher than in other treatment groups. In immunohistochemistry, location of reactions to S-100 in PQQ + Vit E was clearly more positive than in other treatment groups. Response to PQQ + Vit E treatment demonstrates that it influences and improves functional recovery of peripheral nerve regeneration. PMID:24129003

  16. Electrodialysis of Sulfuric Acid with Cation-Exchange Membranes Prepared by Electron-Beam-Induced Graft Polymerization

    NASA Astrophysics Data System (ADS)

    Asari, Yuki; Shoji, Nobuyoshi; Miyoshi, Kazuyoshi; Umeno, Daisuke; Saito, Kyoichi

    Strongly acidic cation-exchange membranes were prepared by the electron-beam-induced graft polymerization of glycidyl methacrylate onto a high-density polyethylene film with a thickness of 35 μm and the subsequent conversion of the resulting epoxy group into a sulfonic acid group. The resulting cation-exchange membranes with various ion-exchange capacities or sulfonic acid group densities ranging from 1.9 to 2.7 mmol/g were applied to the enrichment of 0.50 mol/L sulfuric acid by electrodialysis. Concentrated sulfuric acids at concentrations of 1.4 to 2.9 mol/L were obtained in the concentrate chamber during the electrodialysis operated at 30 mA/cm2 and 298 K, using a pair of this cation-exchange membrane and a commercially available anion-exchange membrane.

  17. A Tat-grafted anti-nucleic acid antibody acquires nuclear-localization property and a preference for TAR RNA

    SciTech Connect

    Jeong, Jong-Geun; Kim, Dong-Sik; Kim, Yong-Sung; Kwon, Myung-Hee

    2011-03-18

    Highlights: {yields} We generate '{sub H3}Tat-3D8' by grafting Tat{sub 48-60} peptide to VH CDR of 3D8 scFv antibody. {yields} {sub H3}Tat-3D8 antibody retains nucleic acid binding and hydrolyzing activities. {yields} {sub H3}Tat-3D8 acquires a preference for TAR RNA structure. {yields} Properties of Tat{sub 48-60} is transferred to an antibody via Tat-grafting into a CDR. -- Abstract: The 3D8 single chain variable fragment (3D8 scFv) is an anti-nucleic acid antibody that can hydrolyze nucleic acids and enter the cytosol of cells without reaching the nucleus. The Tat peptide, derived from the basic region of the HIV-1 Tat protein, translocates to cell nuclei and has TAR RNA binding activity. In this study, we generated a Tat-grafted antibody ({sub H3}Tat-3D8) by replacing complementarity-determining region 3 (CDR3) within the VH domain of the 3D8 scFv with a Tat{sub 48-60} peptide (GRKKRRQRRRPPQ). {sub H3}Tat-3D8 retained the DNA-binding and DNA-hydrolyzing activity of the scFv, and translocated to the nuclei of HeLa cells and preferentially recognized TAR RNA. Thus, the properties associated with the Tat peptide were transferred to the antibody via Tat-grafting without loss of the intrinsic DNA-binding and hydrolyzing activities of the 3D8 scFv antibody.

  18. Glycyrrhetinic acid-modified chitosan nanoparticles enhanced the effect of 5-fluorouracil in murine liver cancer model via regulatory T-cells

    PubMed Central

    Cheng, Mingrong; Xu, Hongzhi; Wang, Yong; Chen, Houxiang; He, Bing; Gao, Xiaoyan; Li, Yingchun; Han, Jiang; Zhang, Zhiping

    2013-01-01

    Modified chitosan nanoparticles are a promising platform for drug, such as 5-fluorouracil (5-FU), gene, and vaccine delivery. Here, we used chitosan and hepatoma cell-specific binding molecule glycyrrhetinic acid (GA) to synthesize glycyrrhetinic acid-modified chitosan (GA-CTS). The synthetic product was confirmed by infrared spectroscopy and hydrogen nuclear magnetic resonance. By combining GA-CTS and 5-FU, we obtained a GA-CTS/5-FU nanoparticle, with a particle size of 193.7 nm, drug loading of 1.56%, and a polydispersity index of 0.003. The GA-CTS/5-FU nanoparticle provided a sustained-release system comprising three distinct phases of quick, steady, and slow release. In vitro data indicated that it had a dose- and time-dependent anticancer effect. The effective drug exposure time against hepatic cancer cells was increased in comparison with that observed with 5-FU. In vivo studies on an orthotropic liver cancer mouse model demonstrated that GA-CTS/5-FU significantly inhibited cancer cell proliferation, resulting in increased survival time. The antitumor mechanisms for GA-CTS/5-FU nanoparticle were possibly associated with an increased expression of regulatory T-cells, decreased expression of cytotoxic T-cell and natural killer cells, and reduced levels of interleukin-2 and interferon gamma. PMID:24187487

  19. Behavior of Surface-Anchored Poly(acrylic acid) Brushes with Grafting Density Gradients on Solid Substrates: 1. Experiment

    SciTech Connect

    Wu,T.; Gong, P.; Szleifer, I.; Vicek, P.; Subr, V.; Genzer, J.

    2007-01-01

    We describe experiments pertaining to the formation of surface-anchored poly(acrylic acid) (PAA) brushes with a gradual variation of the PAA grafting densities on flat surfaces and provide detailed analysis of their properties. The PAA brush gradients are generated by first covering the substrate with a molecular gradient of the polymerization initiator, followed by the 'grafting from' polymerization of tert-butyl acrylate (tBA) from these substrate-bound initiator centers, and finally converting the PtBA into PAA. We use spectroscopic ellipsometry to measure the wet thickness of the grafted PAA chains in aqueous solutions at three different pH values (4, 5.8, and 10) and a series of ionic strengths (IS). Our measurements reveal that at low grafting densities, s, the wet thickness of the PAA brush (H) remains relatively constant, the polymers are in the mushroom regime. Beyond a certain value of s, the macromolecules enter the brush regime, where H increases with increasing s. For a given s, H exhibits a nonmonotonic behavior as a function of the IS. At large IS, the H is small because the charges along PAA are completely screened by the excess of the external salt. As IS decreases, the PAA enters the so-called salt brush (SB) regime, where H increases. At a certain value of IS, H reaches a maximum and then decreases again. The latter is a typical brush behavior in so-called osmotic brush (OB) regime. We provide detailed discussion of the behavior of the grafted PAA chains in the SB and OB regimes.

  20. Hybrid polymeric hydrogels for ocular drug delivery: nanoparticulate systems from copolymers of acrylic acid-functionalized chitosan and N-isopropylacrylamide or 2-hydroxyethyl methacrylate

    NASA Astrophysics Data System (ADS)

    Barbu, Eugen; Verestiuc, Liliana; Iancu, Mihaela; Jatariu, Anca; Lungu, Adriana; Tsibouklis, John

    2009-06-01

    Nanoparticulate hybrid polymeric hydrogels (10-70 nm) have been obtained via the radical-induced co-polymerization of acrylic acid-functionalized chitosan with either N-isopropylacrylamide or 2-hydroxyethyl methacrylate, and the materials have been investigated for their ability to act as controlled release vehicles in ophthalmic drug delivery. Studies on the effects of network structure upon swelling properties, adhesiveness to substrates that mimic mucosal surfaces and biodegradability, coupled with in vitro drug release investigations employing ophthalmic drugs with differing aqueous solubilities, have identified nanoparticle compositions for each of the candidate drug molecules. The hybrid nanoparticles combine the temperature sensitivity of N-isopropylacrylamide or the good swelling characteristics of 2-hydroxyethyl methacrylate with the susceptibility of chitosan to lysozyme-induced biodegradation.

  1. Preparation and characterization of Fe(III)-loaded iminodiacetic acid modified GMA grafted nonwoven fabric adsorbent for anion adsorption

    NASA Astrophysics Data System (ADS)

    Kavaklı, Pınar Akkaş; Kavaklı, Cengiz; Güven, Olgun

    2014-01-01

    An Fe(III)-loaded chelating fabric with iminodiacetic acid (IDA) functional groups was prepared by radiation induced graft polymerization of an epoxy group containing monomer, glycidyl methacrylate, onto a nonwoven fabric made of polypropylene coated by polyethylene (PE/PP) and subsequent Fe(III) loading. Grafting conditions were optimized, and GMA grafted polymer was modified with iminodiacetic acid in isopropyl alcohol/water at 80 °C. In order to prepare the polymeric ligand exchanger (PLE) for the removal of phosphate, IDA fabrics were loaded with Fe(III) ions. Fe(III) loading capacity of IDA fabric was determined to be 2.83 mmol Fe(III)/g of polymer. For removal of phosphate anion, adsorption experiments were performed in batch mode at different pH (2-9) and phosphate concentrations. It was found that phosphate adsorption by the Fe(III)-loaded IDA fabric is maximum at pH 2.00. The effect of initial concentration of phosphate on the adsorption behaviour of Fe(III)-loaded IDA nonwoven fabric was determined at low phosphate concentrations (0.5-25 ppm) and at high phosphate concentrations (50-1000 ppm).

  2. Water absorption and moisture permeation properties of chitosan/poly(acrylamide-co-itaconic acid) IPC films.

    PubMed

    Bajpai, M; Bajpai, S K; Jyotishi, Pooja

    2016-03-01

    In this work, aqueous solutions of chitosan (Ch) and [poly(acrylamide(AAm)-co-itaconicacid(IA)] have been mixed to yield Ch/poly(AAm-co-IA) Inter-polyelectrolyte complex (IPC) films. The films were characterized by FTIR, X-ray diffraction (XRD) and thermo gravimetric analysis (TGA). There was remarkable increase in the crystalline nature of IPC films. The films were investigated for their water absorption capacity in the physiological fluid (PF) of pH 7.4 at 37 °C. The amount of IA present in the film forming solutions affected the water absorption behavior of the resulting films. The dynamic water uptake data were interpreted by various kinetic models. The effect of pH on the swelling ratio (SR) indicated that the films showed highest swelling in lower as well as higher pH media. The water vapor transmission rates (WVTR) were obtained in the range of 6000-6645 g/m(2)/day. PMID:26658228

  3. Enzymatic modification of chitosan with quercetin and its application as antioxidant edible films.

    PubMed

    Torres, E; Marín, V; Aburto, J; Beltrán, H I; Shirai, K; Villanueva, S; Sandoval, G

    2012-01-01

    Quercetin, rutin, naringin, hesperidin and chrysin were tested as substrates for chloroperoxidase to produce reactive quinones to graft onto chitosan. Quercetin and rutin quinones were successfully chemically attached to low molecular weight chitosan. The quercetin-modified chitosan showed an enhancement of plastic, antioxidant and antimicrobial properties as well as of thermal degradability. Finally, chitosan-quercetin films visibly decreased enzymatic oxidation when applied to Opuntia ficus indica cladodes. PMID:22586910

  4. Recent progress on synthesis, property and application of modified chitosan: An overview.

    PubMed

    Wang, Junhua; Wang, Li; Yu, Haojie; Zain-Ul-Abdin; Chen, Yongsheng; Chen, Qing; Zhou, Weidong; Zhang, Hongtao; Chen, Xiao

    2016-07-01

    Because of the unique chemical structure, chitosan and its derivatives have been paid close extensive attention as the potential bio-functional material. This review presents recent synthesis of modified chitosan via N-substitution, O-substitution, free radical graft copolymerization and other modification methods and properties of the modified chitosan. The applications of the modified chitosan in metal ions adsorption, dye removal and pharmaceutical fields are illustrated as well. The rapid development in the modification of chitosan describes broad perspectives of the modified chitosan. PMID:27044349

  5. Enhanced cell affinity of poly( L-lactide) film by immobilizing phosphonized chitosan

    NASA Astrophysics Data System (ADS)

    Tian, Ye; Zhou, Chang-ren; Zeng, Qing-hui; Yang, Ju-lin; Han, Feng-xian; Tian, Jin-huan

    2008-11-01

    Graft polymerization of acrylic acid (AA) onto poly( L-lactide) (PLLA) film by UV irradiation was carried out to develop surfaces for N-methylene phosphonic chitosan (NMPC) immobilization. The properties of modified films were discussed by colorimetric method, attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), contact angles, atomic force microscopy (AFM) and osteoblast incubation. The results showed that AA solution concentration and irradiation time had effect on the graft carboxyl densities. Comparing the ATR-FTIR images, two new peaks at 1561 cm -1 and 1632 cm -1 proved that NMPC was immobilized on the film surface successfully. The water contact-angles were decreased from 90 ± 5° to 37 ± 5° after modification. The AFM images indicated that the surface of the combined film was rougher than that of untreated film. The grafted film provided an excellent substrate for the growth of osteoblast.

  6. Influence of Chitosan Nanoparticles as the Absorption Enhancers on Salvianolic acid B In vitro and In vivo Evaluation

    PubMed Central

    Jin, Xin; Zhang, Shi-bing; Li, Shi-meng; Liang, Ke; Jia, Zeng-yong

    2016-01-01

    Background: Salvianolic acid B (SalB) represents the most abundant and bio-active phenolic constituent among the water-soluble compounds of Salvia miltiorrhiza. But the therapeutic potential of SalB has been significantly restricted by its poor absorption. Methods: In this study, chitosans (CS) and CS nanoparticles (NPs) with different molecular weights (MWs), which have influence on the absorption of SalB, was also investigated. Results: As a preliminary study, water-soluble CS with various MWs (3, 30, 50, and 100 kDa) was chosen. We investigated the MW-dependent Caco-2 cell layer transport phenomena in vitro of CS and NPs at concentrations (4 μg/ml, w/v). SalB, in presence CS or NPs has no significant toxic effect on Caco-2 cell. As the MW increases, the absorption enhancing effect of CS increases. However, as the MW decreases, the absorption enhancing effect of NPs increases. The AUC0–∞ of the SalB-100 kDa CS was 4.25 times greater than that of free SalB. And the AUC0–∞ of the SalB-3 kDa NPs was 16.03 times greater than that of free SalB. Conclusion: CS and NPs with different MWs as the absorption enhancers can promote the absorption of SalB. And the effect on NPs is better than CS. SUMMARY Formation mechanism for NPs PMID:27019562

  7. Relevance of charge balance and hyaluronic acid on alginate-chitosan sponge microstructure and its influence on fibroblast growth.

    PubMed

    Orellana, Sandra L; Giacaman, Annesi; Pavicic, Francisca; Vidal, Alejandra; Moreno-Villoslada, Ignacio; Concha, Miguel

    2016-10-01

    The study of biomaterials by electrical charge scaling to explore the role of net charge on biocompatibility and suitability for tissue regeneration has been limited as has the search for products that could improve this first-rate variable. In the present study, we prepared sponges composed of chitosan/alginate (CS/ALG) with or without hyaluronic acid (HA) by mixing polymer stock solutions of different net electric charge ratios (n(+/) n(-) ), and then lyophilizing them to obtain porous materials. The electric charge ratios n(+/) n(-) studied were 0.3, 0.8, 1.0, and 2.5 for CS/ALG and 0.3, 1.0, 1.9, and 3.7 for CS/ALG/HA sponges. Under these conditions a role for net electric charge balance over sponge microstructure rearrangement, protection to dissolution, cellular proliferation, and cell-cell interactions was apparent, effects that were enhanced by copolymer modification with HA. Mass balance, electric charge, and specific products that influence both such as HA, have a potential in biomaterials for wound healing. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2537-2543, 2016. PMID:27238940

  8. Nano-polyplex based on oleoyl-carboxymethy-chitosan (OCMCS) and hyaluronic acid for oral gene vaccine delivery.

    PubMed

    Liu, Ya; Wang, Fang-Qin; Shah, Zeana; Cheng, Xiao-Jie; Kong, Ming; Feng, Chao; Chen, Xi-Guang

    2016-09-01

    Here we described nano-polyplexes (NPs) made of oleoyl-carboxymethy-chitosan (OCMCS)/hyaluronic acid (HA) as novel potential carriers for oral gene vaccines delivery. Aerolysin gene (aerA) of Aeromonas hydrophila as microbial antigen was efficiently loaded to form OCMCS-HA/aerA (OHA) NPs. OHA NPs performed the optimal parameters, i.e. smallest (154.5±9.4nm), positive charged (+7.9±0.5mV) and monodispersed system with the N/P ratio of 5 and OCMCS/HA weight ratio of 4. Upon the introduction of HA, OHA NPs was beneficial for the DNA release in intestinal environments in comparison to OA NPs. The mean fluorescence intensity detected in Caco-2 cells incubated with OHA NPs was about 2.5-fold higher than that of OA NPs; however, it decreased significantly in the presence of excess free HA. The OHA NPs and OA NPs decreased the transepithelial electric resistance (TEER) of Caco-2 monolayers obviously and induced increasing the apparent permeability coefficient (Papp) of DNA by 5.45-6.09 folds compared with free DNA. Significantly higher (P<0.05) antigen-specific antibodies were detected in serum after orally immunized with OHA NPs than that immunized with OA NPs and DNA alone in carps. These results enable the OHA NPs might resolve challenges arising from gastrointestinal damage to gene antigens, and offer an approach applicable for oral vaccination. PMID:27236511

  9. Towards Acid-Tolerated Ethanol Dehydration: Chitosan-Based Mixed Matrix Membranes Containing Cyano-Bridged Coordination Polymer Nanoparticles.

    PubMed

    Wu, C-W; Kang, Chao-Hsiang; Lin, Yi-Feng; Tung, Kuo-Lun; Deng, Yu-Heng; Ahamad, Tansir; Alshehri, Saad M; Suzuki, Norihiro; Yamauchi, Yusuke

    2016-04-01

    Prussian blue (PB) nanoparticles, one of many cyano-bridged coordination polymers, are successfully incorporated into chitosan (CS) polymer to prepare PB/CS mixed matrix membranes (MMMs). The PB nanoparticles are uniformly distributed in the MMMs without the collapse of the original PB structure. As-prepared PB/CS MMMs are used for ethanol dehydration at 25 °C in the pervaporation process. The effect of loading PB in CS matrix on pervaporation performance is carefully investigated. The PB/CS membrane with 30 wt% PB loading shows the best performance with a permeate flux of 614 g. m-2 . h-1 and a separation factor of 1472. The pervaporation using our PB/CS membranes exhibits outstanding performance in comparison with the previously reported CS-based membranes and MMMs. Furthermore, the addition of PB allows PB/CS MMMs to be tolerant of acidic environment. The present work demonstrates good pervaporation performance of PB/CS MMMs for the separation of an ethanol/water (90:10 in wt%) solution. Our new system provides an opportunity for dehydration of bioethanol in the future. PMID:27451778

  10. Designing novel macroporous composite hydrogels based on methacrylic acid copolymers and chitosan and in vitro assessment of lysozyme controlled delivery.

    PubMed

    Dragan, Ecaterina Stela; Cocarta, Ana Irina; Gierszewska, Magdalena

    2016-03-01

    Designing structure and morphology of macroporous hydrogels is crucial for their applications in controlled release systems of macromolecular drugs. Macroporous hydrogels, consisting of methacrylic acid (MAA) and either acryl amide (AAm) or 2-hydroxyethyl methacrylate (HEMA) (1st network), were prepared for this purpose by cryogelation (single network cryogels, SNCs). Macroporous interpenetrating polymer network (IPN) hydrogel composites were then prepared by a sequential strategy, the 2nd network consisting of chitosan (CS) cross-linked with poly(ethyleneglycol) diglycidyl ether (PEGDGE) being generated by the sorption of a CS and PEGDGE mixture in the 1st network followed by cross-linking. A strong difference in the behavior of SNCs and IPN hydrogel composites was found during the loading and release of lysozyme (LYS) used as macromolecular drug model. Thus, while the amount of LYS loaded on SNCs was higher than that loaded on the IPNs, the release of LYS from SNCs occurred at pH 2, when the ratio between MAA and AAm was 50:50, and only at pH 1 when the ratio between MAA and AAm was 70:30. The 2nd network led to the decrease of the pore size of the IPNs, mainly when the initial concentration of monomers was 10wt/v%, but the presence of CS facilitates the LYS release from IPNs, mainly at a concentration of monomer of 5wt/v%, and when HEMA was used as nonionic comonomer. PMID:26700231

  11. Synergistic Antibacterial Effect and Antibacterial Action Mode of Chitosan-Ferulic Acid Conjugate against Methicillin-Resistant Staphylococcus aureus.

    PubMed

    Eom, Sung-Hwan; Kang, Shin-Kook; Lee, Dae-Sung; Myeong, Jeong-In; Lee, Jinhwan; Kim, Hyun-Woo; Kim, Kyoung-Ho; Je, Jae-Young; Jung, Won-Kyo; Kim, Young-Mog

    2016-04-28

    We evaluated the synergistic antibacterial effect in combination with the chitosan-ferulic acid conjugate (CFA) and β-lactam antibiotics, such as ampicillin, penicillin, and oxacillin, against methicillin-resistant Staphylococcus aureus (MRSA) using fractional inhibitory concentration (FIC) indices. CFA clearly reversed the antibacterial activity of ampicillin, penicillin, and oxacillin against MRSA in the combination mode. Among these antibiotics, the combination of oxacillin-CFA resulted in a ∑FICmin range of 0.250 and ∑FICmax of 0.563, suggesting that the oxacillin-CFA combination resulted in an antibacterial synergy effect against MRSA. In addition, we determined that CFA inhibited the mRNA expression of gene mecA and the production of PBP2a, which is a key determinant for β-lactam antibiotic resistance, in a dosedependent manner. Thus, the results obtained in this study supported the idea on the antibacterial action mechanism that oxacillin will restore the antibacterial activity against MRSA through the suppression of PBP2a production by CFA. PMID:26718468

  12. Hyaluronic acid/chitosan nanoparticles for delivery of curcuminoid and its in vitro evaluation in glioma cells.

    PubMed

    Yang, Liu; Gao, Shiya; Asghar, Sajid; Liu, Guihua; Song, Jue; Wang, Xuan; Ping, Qineng; Zhang, Can; Xiao, Yanyu

    2015-01-01

    The aim of this work was to evaluate the potential of polyelectrolyte complex nanoparticles (PENPs) based on hyaluronic acid/chitosan (HA/CS) as carriers for water-insoluble curcuminoid (CUR) and explore in vitro performance against brain glioma cells. PENPs were observed to be affected by the order of addition, mass ratios and initial concentrations of the HA/CS, pH and ionic strength. PENPs remained stable over a temperature range of 5–-55(C. CUR was successfully encapsulated into the PENPs. CUR-PENPs showed spherical shape with a mean diameter of 207 nm and positive charge of 25.37 mV. High encapsulation efficiency (89.9%) and drug loading (6.5%) was achieved. Drug release studies revealed initial burst release of drug from the PENPs up to 4h followed by sustained release pattern. DSC thermograms and XRD patterns showed that CUR was encapsulated inside the PENPs in a molecular or amorphous state. Compared with CUR-solution, CUR-PENPs showed stronger dose dependent cytotoxicity against C6 glioma cells and higher performance in uptake efficiency in C6 cells. Cellular uptake of CUR-PENPs was found to be governed by multi-mechanism in C6 cells, involving active endocytosis, macropinocytosis, clathrin-, caveolae-, and CD44-mediated endocytosis. In conclusion, CUR-PENPs might be a promising carrier for therapy of brain gliomas. PMID:25450553

  13. Folate-Chitosan Nanoparticles Loaded with Ursolic Acid Confer Anti-Breast Cancer Activities in vitro and in vivo.

    PubMed

    Jin, Hua; Pi, Jiang; Yang, Fen; Jiang, Jinhuan; Wang, Xiaoping; Bai, Haihua; Shao, Mingtao; Huang, Lei; Zhu, Haiyan; Yang, Peihui; Li, Lihua; Li, Ting; Cai, Jiye; Chen, Zheng W

    2016-01-01

    Ursolic acid (UA) has proved to have broad-spectrum anti-tumor effects, but its poor water solubility and incompetent targeting property largely limit its clinical application and efficiency. Here, we synthesized a nanoparticle-based drug carrier composed of chitosan, UA and folate (FA-CS-UA-NPs) and demonstrated that FA-CS-UA-NPs could effectively diminish off-target effects and increase local drug concentrations of UA. Using MCF-7 cells as in vitro model for anti-cancer mechanistic studies, we found that FA-CS-UA-NPs could be easily internalized by cancer cells through a folate receptor-mediated endocytic pathway. FA-CS-UA-NPs entered into lysosome, destructed the permeability of lysosomal membrane, and then got released from lysosomes. Subsequently, FA-CS-UA-NPs localized into mitochondria but not nuclei. The prolonged retention of FA-CS-UA-NPs in mitochondria induced overproduction of ROS and destruction of mitochondrial membrane potential, and resulted in the irreversible apoptosis in cancer cells. In vivo experiments showed that FA-CS-UA-NPs could significantly reduce breast cancer burden in MCF-7 xenograft mouse model. These results suggested that FA-CS-UA-NPs could further be explored as an anti-cancer drug candidate and that our approach might provide a platform to develop novel anti-cancer drug delivery system. PMID:27469490

  14. Oxidative and Molecular Responses in Capsicum annuum L. after Hydrogen Peroxide, Salicylic Acid and Chitosan Foliar Applications

    PubMed Central

    Mejía-Teniente, Laura; de Dalia Durán-Flores, Flor; Chapa-Oliver, Angela María; Torres-Pacheco, Irineo; Cruz-Hernández, Andrés; González-Chavira, Mario M.; Ocampo-Velázquez, Rosalía V.; Guevara-González, Ramón G.

    2013-01-01

    Hydrogen peroxide (H2O2) is an important ROS molecule (Reactive oxygen species) that serves as a signal of oxidative stress and activation of signaling cascades as a result of the early response of the plant to biotic stress. This response can also be generated with the application of elicitors, stable molecules that induce the activation of transduction cascades and hormonal pathways, which trigger induced resistance to environmental stress. In this work, we evaluated the endogenous H2O2 production caused by salicylic acid (SA), chitosan (QN), and H2O2 elicitors in Capsicum annuum L. Hydrogen peroxide production after elicitation, catalase (CAT) and phenylalanine ammonia lyase (PAL) activities, as well as gene expression analysis of cat1, pal, and pathogenesis-related protein 1 (pr1) were determined. Our results displayed that 6.7 and 10 mM SA concentrations, and, 14 and 18 mM H2O2 concentrations, induced an endogenous H2O2 and gene expression. QN treatments induced the same responses in lesser proportion than the other two elicitors. Endogenous H2O2 production monitored during several days, showed results that could be an indicator for determining application opportunity uses in agriculture for maintaining plant alert systems against a stress. PMID:23676352

  15. Folate-Chitosan Nanoparticles Loaded with Ursolic Acid Confer Anti-Breast Cancer Activities in vitro and in vivo

    NASA Astrophysics Data System (ADS)

    Jin, Hua; Pi, Jiang; Yang, Fen; Jiang, Jinhuan; Wang, Xiaoping; Bai, Haihua; Shao, Mingtao; Huang, Lei; Zhu, Haiyan; Yang, Peihui; Li, Lihua; Li, Ting; Cai, Jiye; Chen, Zheng W.

    2016-07-01

    Ursolic acid (UA) has proved to have broad-spectrum anti-tumor effects, but its poor water solubility and incompetent targeting property largely limit its clinical application and efficiency. Here, we synthesized a nanoparticle-based drug carrier composed of chitosan, UA and folate (FA-CS-UA-NPs) and demonstrated that FA-CS-UA-NPs could effectively diminish off-target effects and increase local drug concentrations of UA. Using MCF-7 cells as in vitro model for anti-cancer mechanistic studies, we found that FA-CS-UA-NPs could be easily internalized by cancer cells through a folate receptor-mediated endocytic pathway. FA-CS-UA-NPs entered into lysosome, destructed the permeability of lysosomal membrane, and then got released from lysosomes. Subsequently, FA-CS-UA-NPs localized into mitochondria but not nuclei. The prolonged retention of FA-CS-UA-NPs in mitochondria induced overproduction of ROS and destruction of mitochondrial membrane potential, and resulted in the irreversible apoptosis in cancer cells. In vivo experiments showed that FA-CS-UA-NPs could significantly reduce breast cancer burden in MCF-7 xenograft mouse model. These results suggested that FA-CS-UA-NPs could further be explored as an anti-cancer drug candidate and that our approach might provide a platform to develop novel anti-cancer drug delivery system.

  16. Improved wettability and adhesion of polylactic acid/chitosan coating for bio-based multilayer film development

    NASA Astrophysics Data System (ADS)

    Gartner, Hunter; Li, Yana; Almenar, Eva

    2015-03-01

    The objective of this study was to investigate the effect of methyldiphenyl diisocyanate (MDI) concentration (0, 0.2, 1, 2, and 3%) on the wettability and adhesion of blend solutions of poly(lactic acid) (PLA) and chitosan (CS) when coated on PLA film for development of a bio-based multi-layer film suitable for food packaging and other applications. Characterization was carried out by attenuated total reflectance infrared spectrometry (ATR-FTIR), contact angle (θ), mechanical adhesion pull-off testing, and scanning electron microscopy (SEM). The θ of the PLA/CS blend shifted to a lower value (41-35°) with increasing MDI concentration showing that the surface tension was modified between the PLA/CS blend solution and PLA film and better wettability was achieved. The increase in MDI also resulted in an increased breaking strength (228-303 kPa) due to the increased H-bonding resulting from the more urethane groups formed within the PLA/CS blend as shown by ATR-FTIR. The improved adhesion was also shown by the increased number of physical entanglements observed by SEM. It can be concluded that MDI can be used to improve wettability and adhesion between PLA/CS coating and PLA film.

  17. Folate-Chitosan Nanoparticles Loaded with Ursolic Acid Confer Anti-Breast Cancer Activities in vitro and in vivo

    PubMed Central

    Jin, Hua; Pi, Jiang; Yang, Fen; Jiang, Jinhuan; Wang, Xiaoping; Bai, Haihua; Shao, Mingtao; Huang, Lei; Zhu, Haiyan; Yang, Peihui; Li, Lihua; Li, Ting; Cai, Jiye; Chen, Zheng W.

    2016-01-01

    Ursolic acid (UA) has proved to have broad-spectrum anti-tumor effects, but its poor water solubility and incompetent targeting property largely limit its clinical application and efficiency. Here, we synthesized a nanoparticle-based drug carrier composed of chitosan, UA and folate (FA-CS-UA-NPs) and demonstrated that FA-CS-UA-NPs could effectively diminish off-target effects and increase local drug concentrations of UA. Using MCF-7 cells as in vitro model for anti-cancer mechanistic studies, we found that FA-CS-UA-NPs could be easily internalized by cancer cells through a folate receptor-mediated endocytic pathway. FA-CS-UA-NPs entered into lysosome, destructed the permeability of lysosomal membrane, and then got released from lysosomes. Subsequently, FA-CS-UA-NPs localized into mitochondria but not nuclei. The prolonged retention of FA-CS-UA-NPs in mitochondria induced overproduction of ROS and destruction of mitochondrial membrane potential, and resulted in the irreversible apoptosis in cancer cells. In vivo experiments showed that FA-CS-UA-NPs could significantly reduce breast cancer burden in MCF-7 xenograft mouse model. These results suggested that FA-CS-UA-NPs could further be explored as an anti-cancer drug candidate and that our approach might provide a platform to develop novel anti-cancer drug delivery system. PMID:27469490

  18. Characterization of calcium carbonate/chitosan composites

    SciTech Connect

    Gonsalves, K.E.; Zhang, S.

    1995-12-31

    The crystal growth of calcium carbonate on a chitosan substrate was achieved using a supersaturated calcium carbonate solution, by using various additives, polyacrylic acid (PAA). Polyacrylic acid modified the chitosan-film surface and promoted the nucleation of calcium carbonate crystals.

  19. Covalent grafting of copper amino acid complexes onto chloropropylated silica gel—an FT-IR study

    NASA Astrophysics Data System (ADS)

    Jakab, N. I.; Hernadi, K.; Kiss, J. T.; Pálinkó, I.

    2005-06-01

    Cu(amino acid) complexes were immobilised on silica gel by covalent anchoring. The amino acids were L-histidine and L-tyrosine and their BOC—( tert-butoxycarbonyl) or methyl ester protected derivatives. To gain control over the synthesis the appropriately protected amino acid was reacted with chloropropylated silica gel first. This modified material as is, or after deprotecting the anchored amino acids, was used in further steps of building the immobilised Cu(II) complex. The covalently grafted complexes were studied by FT-IR spectroscopy and computer modelling. Materials containing protected histidine ligands showed catalase activity (decomposition of H 2O 2), those containing protected or unprotected tyrosine ligands displayed tyrosinase activity (the decomposed H 2O 2 oxidised the tyrosine skeleton to a quinoidal structure).

  20. Release of a chitosan-hydroxyapatite composite loaded with ibuprofen and acetyl-salicylic acid submitted to different sterilization treatments

    NASA Astrophysics Data System (ADS)

    Larena, A.; Cáceres, D. A.; Vicario, C.; Fuentes, A.

    2004-11-01

    It has been demonstrated that chitosan-hydroxyapatite composite induces osteoconductivity in osseous defects but also could act as drug vehicle. It is important be able to load these composites with short-time life and controlled action anti-inflammatories to reduce or eliminate undesirable inflammatory processes. The goal of the present study is to define the variation between surface properties that this composite experiments as consequence of several sterilization treatments, and application of several pharmaceutical products relating with physical properties. Morphological changes on surface, achieved by polarization and confocal microscopies, thermal and physical properties of chitosan composites and the NSAIDs release process kinetics so as the sterilization treatment effects observed by UV-vis spectroscopy were studied. In this article, it has been demonstrated that the kind of sterilization has no important influence in NSAIDs release in chitosan membranes or composites but differs a little with chitosan membranes no submitted to sterilization treatments.

  1. Well-organized neointima of large-pore poly(l-lactic acid) vascular graft coated with poly(l-lactic-co-ε-caprolactone) prevents calcific deposition compared to small-pore electrospun poly(l-lactic acid) graft in a mouse aortic implantation model

    PubMed Central

    Tara, Shuhei; Kurobe, Hirotsugu; Rocco, Kevin A.; Maxfield, Mark W.; Best, Cameron A.; Yi, Tai; Naito, Yuji; Breuer, Christopher K.; Shinoka, Toshiharu

    2014-01-01

    Objective Tissue engineering techniques have emerged that allow bioresorbable grafts to be implanted that restore function and transform into biologically active arteries. However, these implants are susceptible to calcification during the remodeling process. The objective of this study was to evaluate the role of pore size of bioabsorbable grafts in the development of calcification. Methods Two types of grafts were prepared: a large-pore graft constructed of poly(l-lactic acid) (PLA) fibers coated with poly(l-lactide-co-ε-caprolactone) (PLCL) (PLA-PLCL), and a small-pore graft made of electrospun PLA nanofibers (PLA-nano). Twenty-eight PLA-PLCL grafts and twenty-five PLA-nano grafts were implanted as infra-renal aortic interposition conduits in 8-week-old female SCID/Bg mice, and followed for 12 months after implantation. Results Large-pore PLA-PLCL grafts induced a well-organized neointima after 12 months, and Alizarin Red S staining showed neointimal calcification only in the thin neointima of small-pore PLA-nano grafts. At 12 months, macrophage infiltration, evaluated by F4/80 staining, was observed in the thin neointima of the PLA-nano graft, and there were few vascular smooth muscle cells (VSMCs) in this layer. On the other hand, the neointima of the PLA-PLCL graft was composed of abundant VSMCs, and a lower density of macrophages (F4/80 positive cells, PLA-PLCL; 68.1±41.4/mm2 vs PLA-nano; 188.3±41.9/mm2, p = 0.007). The VSMCs of PLA-PLCL graft expressed transcription factors of both osteoblasts and osteoclasts. Conclusion These findings demonstrate that in mouse arterial circulation, large-pore PLA-PLCL grafts created a well-organized neointima and prevented calcific deposition compared to small-pore, electrospun PLA-nano grafts. PMID:25463106

  2. Mucoadhesive Chitosan Derivatives as Novel Drug Carriers.

    PubMed

    Islam, Mohammad Ariful; Park, Tae-Eun; Reesor, Emma; Cherukula, Kondareddy; Hasan, Anwarul; Firdous, Jannatul; Singh, Bijay; Kang, Sang-Kee; Choi, Yun-Jaie; Park, In-Kyu; Cho, Chong-Su

    2015-01-01

    Chitosan on its own is a well-established natural polymer and is widely regarded as a biodegradable, biocompatible and nontoxic material for drug delivery applications. Although unmodified chitosan has some mucoadhesive properties on its own, its bioavailability is limited due to its short retention time in the body. Moreover, the high solubility of chitosan at acidic pH levels limits its use for mucosal drug delivery (especially through the oral route). Chemically-modified mucoadhesive chitosan, especially thiolated chitosan, has arisen as an alternative to create novel mucosal drug delivery systems. The mucoadhesive properties that are conferred to the thiolated chitosan certainly set this novel class of second or third-generation thiomers apart. To understand the significance of mucoadhesive chitosan, we first present the mechanism of mucoadhesion and provide comprehensive coverage of description of a variety of chemical modifications to prepare mucoadhesive thiolated chitosan derivatives. We then present the plethora of applications of these modified chitosan variants in a wide range of drug delivery fields, including the delivery of antigens, proteins and genes through a variety of routes, including oral, nasal, pulmonary, vaginal and others. By presenting the range of applications for mucoadhesive chitosan drug carriers we herein demonstrate that chemically-modified thiolated chitosan is a versatile and effective material for a new class of drug delivery vehicles. PMID:26323422

  3. High surface-area amidoxime-based polymer fibers co-grafted with various acid monomers yielding increased adsorption capacity for the extraction of uranium from seawater.

    PubMed

    Oyola, Yatsandra; Dai, Sheng

    2016-06-01

    Uranium is dissolved in the ocean at a uniform concentration of 3.34 ppb, which translates to approximately 4-5 billion tons of uranium. The development of adsorbents that can extract uranium from seawater has been a long term goal, but the extremely dilute uranium concentration along with the competition of other metal salts (which are at higher concentrations) has hindered the development of an economical adsorption process. Several acid monomers were co-grafted with acrylonitrile (AN) to help increase the hydrophilicity of the adsorbent to improve access to the metal adsorption sites. Grafting various acid monomers on PE fibers was found to significantly affect the uranium adsorption in simulated seawater in the following order: acrylic acid (AA) < vinyl sulfonic acid (VSA) < methacrylic acid (MAA) < itaconic acid (ITA) < vinyl phosphonic acid (VPA). Interestingly, the uranium adsorption capacity significantly increased when Mohr's salt was added with acrylic acid, most likely due to the reduction of co-polymerization of the monomers. When testing under more realistic conditions, the acid-grafted PE fiber adsorbents were exposed to natural seawater (more dilute uranium), the uranium adsorption capacity increased in the following order: MAA < AA (Mohr's salt) < VSA < ITA (Mohr's salt) < ITA < VPA, which agreed well with the simulated seawater results. Characterization of the adsorbents indicated that the increase in uranium adsorption capacity with each acid monomer was related to higher grafting of AN and therefore a higher conversion to amidoxime (AO). PMID:27145863

  4. The potential application of hyaluronic acid coated chitosan nanoparticles in ocular delivery of dexamethasone.

    PubMed

    Kalam, Mohd Abul

    2016-08-01

    This study investigates in-vitro transcorneal permeation on excised-rabbit cornea and its effect on corneal hydration-level, in-vivo ocular irritation, tear and aqueous humor dexamethasone-sodium-phosphate (DEX) concentration after topical administration of chitosan-nanoparticles (CS-NPs), hyaluronan-coated-CS-NPs (HA-CS-NPs) and DEX-aqueous-solution in rabbit eyes. The permeation parameters and irritation results indicated the ocular safety of NPs. The developed UPLC-method was successfully applied for DEX quantification in tears and aqueous-humors. Tear samples were collected and DEX-concentration was analyzed by UPLC. A statistically significantly (p<0.05) high DEX-concentration in the inferior conjunctival-sulcus from NPs treated eyes was found as compared to DEX-solution treated eyes. Similarly, DEX-concentration in aqueous-humor was estimated. The drug was detected sufficiently high in aqueous-humor till 24h following topical administration of NPs. The NPs have shown significantly (p<0.05) higher bioavailability of DEX compared to DEX-solution. About 1.83- and 2.14-fold higher AUC0-24h was observed with the CS-NPs and HA-CS-NPs, respectively compared to DEX-solution. The reason for higher tear concentration and higher bioavailability of DEX from uncoated and HA-coated CS-NPs was assumed due to their prolonged precorneal-retention because of highly mucoadhesive characteristics of CS and HA. Moreover, presence of HA on CS-NPs, speed-up cellular-uptake by receptor-mediated-endocytosis could be another reason for enhanced bioavailability. PMID:27164496

  5. Structural properties of films and rheology of film-forming solutions of chitosan gallate for food packaging.

    PubMed

    Wu, Chunhua; Tian, Jinhu; Li, Shan; Wu, Tiantian; Hu, Yaqin; Chen, Shiguo; Sugawara, Tatsuya; Ye, Xingqian

    2016-08-01

    The chitosan gallates (CG) were obtained by free-radical-initiated grafting of gallic acid (GA) onto chitosan (CS) in this work. The chemical structures of the CG were corroborated by UV-vis, GPC and (1)H NMR analysis. The grafting reaction was accompanied with a degradation of the CS molecule. The shear-thinning flow behavior of CG film-forming solutions (CG FFS) decreased with the grafting amount of GA into CS chain, while the CG FFS grafted at a lower GA value behaved like a networks containing entangled or cross-linked polymer chains with a more elastic behavior. The increasing of GA grafting onto the CS chain led to a reduction of tensile strength, elongation at break and water resistance in the corresponding films, but increases in the antioxidant and antimicrobial activities were observed. The microstructure of the film was investigated using scanning electron and atomic force microscope, and the results were closely related to the observed film properties. PMID:27112845

  6. Facile one-pot preparation and functionalization of luminescent chitosan-poly(methacrylic acid) microspheres based on polymer monomer pairs

    NASA Astrophysics Data System (ADS)

    Guo, Jia; Wang, Changchun; Mao, Weiyong; Yang, Wuli; Liu, Changjia; Chen, Jiyao

    2008-08-01

    In this paper, we present a facile and robust approach to synthesize multifunctional organic/inorganic composite microspheres with chitosan-poly(methacrylic acid) (CS-PMAA) shells and cadmium tellurium/iron oxide nanoparticle cores. Due to the strong electrostatic interaction between the negatively charged nanoparticles and the protonated CS polymers, the CS/nanoparticle complexes were utilized as templates for the subsequent polymerization of methacrylic acid. The resulting composite microspheres with luminescence and magnetic properties have regular morphologies and narrow size distributions. In contrast to previous reports, this route was based on a one-pot strategy without the aid of surfactants, organic solvent, or polymerizable ligands in aqueous solution. The encapsulated CdTe semiconductor nanocrystals inside the microspheres exhibited strong and stable photoluminescence properties in the pH range 5.0-11.0. When the pH was adjusted below 4, the photoluminescence decreased sharply and even quenched completely. However, the weakened fluorescence emission could be recovered to some degree upon an increase of pH above 5. Additionally, when both Fe3O4 and CdTe nanoparticles were encapsulated within CS-PMAA microspheres, the magnetic content of the microspheres could be efficiently controlled by tuning the feeding molar ratio of MAA monomers and glucosamine units of CS. From the preliminary attempts, it was found that the multifunctional microspheres as imaging agents could improve the rate and extent of cellular uptake under short-term exposure to an applied magnetic field, and so exhibit a great potential as bioactive molecule carriers.

  7. Hair dye-incorporated poly-γ-glutamic acid/glycol chitosan nanoparticles based on ion-complex formation

    PubMed Central

    Lee, Hye-Young; Jeong, Young-IL; Choi, Ki-Choon

    2011-01-01

    Background p-Phenylenediamine (PDA) or its related chemicals are used more extensively than oxidative hair dyes. However, permanent hair dyes such as PDA are known to have potent contact allergy reactions in humans, and severe allergic reactions are problematic. Methods PDA-incorporated nanoparticles were prepared based on ion-complex formation between the cationic groups of PDA and the anionic groups of poly(γ-glutamic acid) (PGA). To reinforce PDA/PGA ion complexes, glycol chitosan (GC) was added. PDA-incorporated nanoparticles were characterized using field-emission scanning electron microscopy, Fourier- transform infrared (FT-IR) spectroscopy, dynamic light scattering, and powder X-ray diffractometry (XRD). Results Nanoparticles were formed by ion-complex formation between the amine groups of PDA and the carboxyl groups of PGA. PDA-incorporated nanoparticles are small in size (<100 nm), and morphological observations showed spherical shapes. FT-IR spectra results showed that the carboxylic acid peak of PGA decreased with increasing PDA content, indicating that the ion complexes were formed between the carboxyl groups of PGA and the amine groups of PDA. Furthermore, the intrinsic peak of the carboxyl groups of PGA was also decreased by the addition of GC. Intrinsic crystalline peaks of PDA were observed by XRD. This crystalline peak of PDA was completely nonexistent when nanoparticles were formed by ion complex between PDA, PGA, and GC, indicating that PDA was complexed with PGA and no free drug existed in the formulation. During the drug-release experiment, an initial burst release of PDA was observed, and then PDA was continuously released over 1 week. Cytotoxicity testing against HaCaT human skin keratinocyte cells showed PDA-incorporated nanoparticles had lower toxicity than PDA itself. Furthermore, PDA-incorporated nanoparticles showed reduced apoptosis and necrosis reaction at HaCaT cells. Conclusion The authors suggest that these microparticles are ideal

  8. A new synthetic methodology for the preparation of biocompatible and organo-soluble barbituric- and thiobarbituric acid based chitosan derivatives for biomedical applications.

    PubMed

    Shahzad, Sohail; Shahzadi, Lubna; Mahmood, Nasir; Siddiqi, Saadat Anwar; Rauf, Abdul; Manzoor, Faisal; Chaudhry, Aqif Anwar; Rehman, Ihtesham Ur; Yar, Muhammad

    2016-09-01

    Chitosan's poor solubility especially in organic solvents limits its use with other organo-soluble polymers; however such combinations are highly required to tailor their properties for specific biomedical applications. This paper describes the development of a new synthetic methodology for the synthesis of organo-soluble chitosan derivatives. These derivatives were synthesized from chitosan (CS), triethyl orthoformate and barbituric or thiobarbituric acid in the presence of 2-butannol. The chemical interactions and new functional motifs in the synthesized CS derivatives were evaluated by FTIR, DSC/TGA, UV/VIS, XRD and (1)H NMR spectroscopy. A cytotoxicity investigation for these materials was performed by cell culture method using VERO cell line and all the synthesized derivatives were found to be non-toxic. The solubility analysis showed that these derivatives were readily soluble in organic solvents including DMSO and DMF. Their potential to use with organo-soluble commercially available polymers was exploited by electrospinning; the synthesized derivatives in combination with polycaprolactone delivered nanofibrous membranes. PMID:27207049

  9. Fabrication and characterization of novel starch-grafted poly l-lactic acid/montmorillonite organoclay nanocomposites.

    PubMed

    Eğri, Özlem; Salimi, Kouroush; Eğri, Sinan; Pişkin, Erhan; Rzayev, Zakir M O

    2016-02-10

    In this work, poly(L-lactic acid)-g-starch layered silicate nanocomposites (NCs) (PLLA-g-starch/MMT) were fabricated by intercalative bulk graft copolymerization of LA with starch, in the presence of either stannous octoate acting as a catalyst or LA-MMT organoclay acting as a cocatalyst-nanofiller. This procedure was performed inside a custom vacuum micro-reactor. To better understand the graft copolymerization mechanism, in situ processing types, interfacial interactions and nanostructure formation of PLLA-g-starch/MMT NCs, methods such as FT-IR, XRD, (1)H NMR, (13)C CP/MAS-NMR, DSC/TGA, TEM and SEM were utilized. The morphology and thermal behaviors of nanocomposites were found to be strongly dependent on the loading mass fraction of LA-MMT within the nanocomposite structure and the type of in situ processing such as interfacial, physical and chemical interactions. Preintercalated LA-MMT organoclay exhibited dual functions. It demonstrated the ability to act as a catalyst, essentially accelerating in situ graft copolymerization via esterification of LA carboxyl groups with hydroxyl groups of starch macromolecules, whilst also acting as a nananofiller-compatibilizer. PMID:26686111

  10. Skin graft

    MedlinePlus

    Skin transplant; Skin autografting; FTSG; STSG; Split thickness skin graft; Full thickness skin graft ... site. Most people who are having a skin graft have a split-thickness skin graft. This takes ...

  11. Swelling and Surface Interactions of End-Grafted Poly(2-vinylpyridine) Layers in Acidic Solution: Influence of Grafting Density and Salt Concentration.

    PubMed

    Elmahdy, Mahdy M; Drechsler, Astrid; Uhlmann, Petra; Stamm, Manfred

    2016-06-01

    In previous studies, the authors found that end-grafted layers of the weak polybase poly(2-vinylpyridine) (P2VP) in aqueous solutions do not only swell and collapse if the pH value and salt concentration are varied but also exhibit a pH- and salinity-dependent adhesion to microsized silica spheres. For a better understanding of these effects, in situ force measurements using the AFM colloidal probe technique were applied to end-grafted P2VP layers of different grafting densities in NaCl solutions at pH 2.5. Although a mushroom-to-brush transition could be seen in the dry state, the layers were in the brush regime in aqueous solutions at all NaCl concentrations and grafting densities. We observed an increase of the brush height with increasing grafting density and a salinity-dependent collapse and reswelling of the brushes. The adhesion between the P2VP layer and a silica sphere depended on both grafting density and salinity. At low salt concentrations, the adhesion reached its highest value at the intermediate grafting density and disappeared with denser brushes. Maximum adhesion was obtained for high NaCl concentrations and the lowest grafting density. From a detailed analysis of the experiments, we gained insight into chain stretching and density profiles under complex ionic conditions and into the mechanism of adhesion of polyelectrolytes to solid surfaces. PMID:27172173

  12. Development of chitosan graft pluronic®F127 copolymer nanoparticles containing DNA aptamer for paclitaxel delivery to treat breast cancer cells

    NASA Astrophysics Data System (ADS)

    Thach Nguyen, Kim; Le, Duc Vinh; Do, Dinh Ho; Huan Le, Quang

    2016-06-01

    HER-2/ErbB2/Neu(HER-2), a member of the epidermal growth factor receptor family, is specifically overexpressed on the surface of breast cancer cells and serves a therapeutic target for breast cancer. In this study, we aimed to isolate DNA aptamer (Ap) that specifically bind to a HER-2 overexpressing SK-BR-3 human breast cancer cell line, using SELEX strategy. We developed a novel multifunctional composite micelle with surface modification of Ap for targeted delivery of paclitaxel. This binary mixed system consisting of Ap modified pluronic®F127 and chitosan could enhance PTX loading capacity and increase micelle stability. Polymeric micelles had a spherical shape and were self-assemblies of block copolymers of approximately 86.22 ± 1.45 nm diameter. PTX could be loaded with high encapsulation efficiency (83.28 ± 0.13%) and loading capacity (9.12 ± 0.34%). The release profile were 29%–35% in the first 12 h and 85%–93% after 12 d at pH 7.5 of receiving media. The IC50 doses by MTT assay showed the greater activity of nanoparticles loaded paclitaxel over free paclitaxel and killed cells up to 95% after 6 h. These results demonstrated unique assembly with the capacity to function as an efficient detection and delivery vehicle in the biological living system.

  13. Characterization of glycol chitosan grafted with low molecular weight polyethylenimine as a gene carrier for human adipose-derived mesenchymal stem cells.

    PubMed

    Bae, Yoonhee; Lee, Young Hwa; Lee, Sunray; Han, Jin; Ko, Kyung Soo; Choi, Joon Sig

    2016-11-20

    Mesenchymal stem cells (MSCs) have a great capacity for self-renewal while still maintaining their multipotency, and can differentiate into a variety of cell types. The delivery of genes to a site of injury is a current and interesting field of gene therapy. In the present study, we describe a nonviral gene delivery carrier, glycol chitosan-methyl acrylate-polyethylenimine (GMP) polymer targeted towards human adipose-derived mesenchymal stem cells (AD-MSCs). Transfection efficiency, using luciferase (Luc) and a pDNA encoding enhanced green fluorescent protein (EGFP), along with cytotoxicity assays, were performed in human AD-MSCs. The results show that the transfection efficiency of the GMP polymer was similar to that of PEI25kD, and the cytotoxicity was lower. Moreover, human AD-MSCs were treated with the GMP polymer/pDNA polyplex and its cellular uptake and distribution were analyzed by flow cytometry and confocal microscopy. Furthermore, we performed endosomal escape analysis using LysoTracker Red, and found that the conjugated GMP polymer could escape from the endosome to the cytosol. Human AD-MSCs treated with the GMP polymer maintained their potential for osteogenic differentiation and phenotypic expression of human AD-MSCs based on flow cytometry analysis. The present study demonstrates that the GMP polymer can be used as a potential targeted-delivery carrier for effective gene delivery. PMID:27561509

  14. Single-layer MoS2 nanosheet grafted upconversion nanoparticles for near-infrared fluorescence imaging-guided deep tissue cancer phototherapy

    NASA Astrophysics Data System (ADS)

    Han, Jianyu; Xia, Hongping; Wu, Yafeng; Kong, Shik Nie; Deivasigamani, Amudha; Xu, Rong; Hui, Kam M.; Kang, Yuejun

    2016-04-01

    A multifunctional nanostructure is prepared by covalently grafting upconversion nanoparticles (UCNPs) with chitosan functionalized MoS2 (MoS2-CS) and folic acid (FA) and then loading phthalocyanine (ZnPc) on the surface of MoS2, which integrates photodynamic therapy (PDT) with photothermal therapy (PTT) and upconversion luminescence imaging into one system for enhanced antitumor efficiency.A multifunctional nanostructure is prepared by covalently grafting upconversion nanoparticles (UCNPs) with chitosan functionalized MoS2 (MoS2-CS) and folic acid (FA) and then loading phthalocyanine (ZnPc) on the surface of MoS2, which integrates photodynamic therapy (PDT) with photothermal therapy (PTT) and upconversion luminescence imaging into one system for enhanced antitumor efficiency. Electronic supplementary information (ESI) available: Experimental details and figures. See DOI: 10.1039/c6nr00150e

  15. Properties of extruded starch-poly(methyl acrylate) graft copolymers prepared from spherulites formed from amylose-oleic acid inclusion complexes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mixtures of high amylose corn starch and oleic acid were processed by steam jet-cooking, and the dispersions were rapidly cooled to yield amylose-oleic acid inclusion complexes as sub-micron spherulites and spherulite aggregates. Dispersions of these spherulite particles were then graft polymerized ...

  16. Specific interactions in modified chitosan systems.

    PubMed

    Rinaudo, M; Auzely, R; Vallin, C; Mullagaliev, I

    2005-01-01

    This paper concerns the bulk and interfacial properties of a series of alkylated chitosans having different alkyl chain lengths grafted randomly along the main chitosan chain. Chitosan has a low degree of acetylation (5%); on chitosan derivatives, the role of the degree of grafting and of length of the alkyl chains are examined. The optimum alkyl chain length is C12 and the degree of grafting 5% to get physical gelation based on the formation of hydrophobic domains. The cross-linking is essentially controlled by the salt concentration: it is shown that 0.025 M AcONa is needed to screen electrostatic interchain repulsions. Hydrophobic interactions produce highly non-Newtonian behavior with large thinning behavior; this behavior is suppressed in the presence of cyclodextrins able to cap the hydrophobic alkyl chains. The interfacial properties of the chitosan derivatives were tested for the air/aqueous solution interfaces. Specifically, the role of their structure on the kinetic of film formation was examined showing that excess of external salt favors the stabilization of the interfacial film. The derivatives with a higher degree of substitution and longer alkyl chains are more efficient and give a higher elastic modulus compared to the model surfactant as a result of the chain properties. PMID:16153074

  17. Immobilization of BSA, enzymes and cells of Bacillus stearothermophilus onto cellulose polygalacturonic acid and starch based graft copolymers containing maleic arhydride

    SciTech Connect

    Beddows, C.G.; Gil, M.H.; Guthrie, J.T.

    1986-01-01

    Poly(maleic anhydride styrene) graft copolymers of cellulose, pectin polygalacturonic acid salt, calcium polygalacturonate, and starch were prepared and used to immobilize proteins. The cellulose grafts coupled quite appreciable quantities of acid phosphatase, glucose oxidase, and trypsin. However, the general retention of activity was somewhat disappointing. Further investigation with acid phosphatase showed that the amount of enzyme immobilized increased as the amount of anhydride in the graft copolymer increased but no such relationship existed for the enzymic activity. The cellulose graft copolymers were hydrolyzed and it appeared that the carboxyl group aided adsorption of the enzyme. Attempts to couple acid phosphatase using CMC through the free carboxyl groups, created by hydrolysis, gave only a small increase in the extent of protein coupling. However, the unhydrolyzed system gave a useful degree of immobilization of cells of Bacillus stearothermophilus, as did a poly(maleic anhydride/styrene)-cocellulose system. Attempts to improve the activity by using grafts based on other polysaccharide supports met with mixed success. Pectin products were soluble. Polygalacturonic acid products were partially soluble and extremely high levels of enzymic activity were obtained. This was probably due in part to the hydrophilic nature of the system, which also encouraged absorption of the enzyme. Attempts were made to reduce the solubility by using the calcium pectinate salt. Immobilization of acid phosphatase and trypsin resulted in increased protein coupling but relatively poor activities were attained. Calcium polygalacturonate was used to prepare an insoluble graft copolymeric system containing acrylonitrile-comaleic anhydride. The resulting gels gave excellent coupling with acid phosphatase which had a very good retention of activity.

  18. Blood contact properties of ascorbyl chitosan.

    PubMed

    Yalinca, Z; Yilmaz, E; Taneri, B; Bullici, F; Tuzmen, S

    2013-01-01

    Ascorbyl chitosan was synthesized by heating chitosan with ascorbic acid in isopropanol. The products were characterized by FTIR and C-13 NMR spectroscopies, SEM, and elemental analysis. Blood contact properties of ascorbyl chitosans were evaluated. The ascorbyl chitosans demonstrated to have increased lipid-lowering activity in comparison to chitosan alone upon contact with human blood serum in in vitro conditions. Furthermore, the total cholesterol/HDL ratio was improved towards the desirable ideal values after three hours contact with ascorbyl chitosan samples. The lipid-lowering activity increased with ascorbyl substitution. The inherent nonspecific adsorption capability of chitosan due to its chelating power with several different functional groups was exhibited by ascorbyl chitosans as well. This behavior was exemplified in a simultaneous decrease in the total iron values of the volunteers together with lower lipid levels. Furthermore, ascorbyl chitosans were observed to have less hemocompatibility but increased anticoagulant activity when compared to chitosan alone. Additional in vivo studies are necessary to support these results and to investigate further the advantages and disadvantages of these materials to prove their safety prior to clinical applications. PMID:23862665

  19. Synthesis and Characterization of Surface Grafted Poly(N-isopropylacrylamide) and Poly(Carboxylic Acid)– Iron Particles via Atom Transfer Radical Polymerization for Biomedical Applications

    PubMed Central

    Sutrisno, Joko; Fuchs, Alan; Evrensel, Cahit

    2014-01-01

    This research relates to the preparation and characterization of surface grafted poly(N-isopropylacrylamide) and poly(carboxylic acid)–micron-size iron particles via atom transfer radical polymerization (ATRP). The surface grafted polymers–iron particles result in multifunctional materials which can be used in biomedical applications. The functionalities consist of cell targeting, imaging, drug delivery, and immunological response. The multifunctional materials are synthesized in two steps. First, surface grafting is used to place polymer molecules on the iron particles surface. The second step, is conjugation of the bio-molecules onto the polymer backbone. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy were used to confirm the presence of polymers on the iron particles. The thickness of the grafted polymers and glass transition temperature of the surface grafted polymers were determined by transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The covalent bond between grafted polymers and iron particles caused higher glass transition temperature as compared with non-grafted polymers. The ability to target the bio-molecule and provide fluorescent imaging was simulated by conjugation of rat immunoglobulin and fluorescein isothiocyanate (FITC) labeled anti-rat. The fluorescence intensity was determined using flow cytometry and conjugated IgG-FITC anti-rat on iron particles which was imaged using a fluorescence microscopy. PMID:25382869

  20. Radiation grafting of pH-sensitive acrylic acid and 4-vinyl pyridine onto nylon-6 using one- and two-step methods

    NASA Astrophysics Data System (ADS)

    Ortega, Alejandra; Alarcón, Darío; Muñoz-Muñoz, Franklin; Garzón-Fontecha, Angélica; Burillo, Guillermina

    2015-04-01

    Acrylic acid (AAc) and 4-vinyl pyridine (4VP) were γ-ray grafted onto nylon-6 (Ny6) films via pre-irradiation oxidative method. These monomers were grafted using a one-step method to render Ny6-g-(AAc/4VP). A two-step or sequential method was used to render (Ny6-g-AAc)-g-4VP. Random copolymer branches were obtained when the grafting was carried out via one-step method using the two monomers together. The two-step method was applied to graft chains of 4VP on both Ny6 substrate and previously grafted AAc chains (Ny6-g-AAc). The two types of binary copolymers synthesized were characterized to determine the amount of grafted polymers, the thermal behavior (DSC and TGA), the surface composition (XPS), and the pH responsiveness. In the two-step process, it is possible to achieve a higher graft yield, better control of the amount of each monomer, good reversibility in the swelling/deswelling process and shorter time to achieve equilibrium swelling.

  1. Controlled delivery of the popular nonsteroidal anti-inflammatory drug, paracetamol, from chitosan-g-polyacrylamide microspheres prepared by the emulsion crosslinking technique.

    PubMed

    Bulut, Emine

    2016-09-01

    In this paper, chitosan-graft-polyacrylamide (CS-g-PAAm) microspheres as drug delivery matrices of paracetamol were prepared by the emulsion crosslinking technique, using glutaraldehyde (GA) as a crosslinker. Graft copolymer of chitosan with acrylamide was synthesized using cerium (IV) ammonium nitrate (CAN). The microspheres formed had average particle sizes in the range of 78-252 μm. Paracetamol entrapment efficiency was found to vary between 31.89% and 72.61%, as determined by UV spectroscopy. Drug release in acidic and phosphate buffer solutions (pH 1.2 and 7.4) of the CS-g-PAAm microspheres was influenced by formulation factors such as the concentration of CS-g-PAAm, the paracetamol/polymer ratio (w/w), and the amount of crosslinker. PMID:25985724

  2. Poly (acrylic acid sodium) grafted carboxymethyl cellulose as a high performance polymer binder for silicon anode in lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Wei, Liangming; Chen, Changxin; Hou, Zhongyu; Wei, Hao

    2016-01-01

    The design of novel binder systems is required for the high capacity silicon (Si) anodes which usually undergo huge volume change during the charge/discharge cycling. Here, we introduce a poly (acrylic acid sodium)-grafted-carboxymethyl cellulose (NaPAA-g-CMC) copolymer as an excellent binder for Si anode in lithium ion batteries (LIBs). The NaPAA-g-CMC copolymer was prepared via a free radical graft polymerization method by using CMC and acrylic acid as precursors. Unlike the linear, one-dimensional binders, the NaPAA-g-CMC copolymer binder is expected to present multi-point interaction with Si surface, resulting in enhanced binding ability with Si particles as well as with the copper (Cu) current collectors, and building a stable solid electrolyte interface (SEI) layer on the Si surface. The NaPAA-g-CMC based Si anode shows much better cycle stability and higher coulombic efficiency than those made with the well-known linear polymeric binders such as CMC and NaPPA.

  3. Poly (acrylic acid sodium) grafted carboxymethyl cellulose as a high performance polymer binder for silicon anode in lithium ion batteries.

    PubMed

    Wei, Liangming; Chen, Changxin; Hou, Zhongyu; Wei, Hao

    2016-01-01

    The design of novel binder systems is required for the high capacity silicon (Si) anodes which usually undergo huge volume change during the charge/discharge cycling. Here, we introduce a poly (acrylic acid sodium)-grafted-carboxymethyl cellulose (NaPAA-g-CMC) copolymer as an excellent binder for Si anode in lithium ion batteries (LIBs). The NaPAA-g-CMC copolymer was prepared via a free radical graft polymerization method by using CMC and acrylic acid as precursors. Unlike the linear, one-dimensional binders, the NaPAA-g-CMC copolymer binder is expected to present multi-point interaction with Si surface, resulting in enhanced binding ability with Si particles as well as with the copper (Cu) current collectors, and building a stable solid electrolyte interface (SEI) layer on the Si surface. The NaPAA-g-CMC based Si anode shows much better cycle stability and higher coulombic efficiency than those made with the well-known linear polymeric binders such as CMC and NaPPA. PMID:26786315

  4. Poly (acrylic acid sodium) grafted carboxymethyl cellulose as a high performance polymer binder for silicon anode in lithium ion batteries

    PubMed Central

    Wei, Liangming; Chen, Changxin; Hou, Zhongyu; Wei, Hao

    2016-01-01

    The design of novel binder systems is required for the high capacity silicon (Si) anodes which usually undergo huge volume change during the charge/discharge cycling. Here, we introduce a poly (acrylic acid sodium)-grafted-carboxymethyl cellulose (NaPAA-g-CMC) copolymer as an excellent binder for Si anode in lithium ion batteries (LIBs). The NaPAA-g-CMC copolymer was prepared via a free radical graft polymerization method by using CMC and acrylic acid as precursors. Unlike the linear, one-dimensional binders, the NaPAA-g-CMC copolymer binder is expected to present multi-point interaction with Si surface, resulting in enhanced binding ability with Si particles as well as with the copper (Cu) current collectors, and building a stable solid electrolyte interface (SEI) layer on the Si surface. The NaPAA-g-CMC based Si anode shows much better cycle stability and higher coulombic efficiency than those made with the well-known linear polymeric binders such as CMC and NaPPA. PMID:26786315

  5. PEG-detachable and acid-labile cross-linked micelles based on orthoester linked graft copolymer for paclitaxel release

    NASA Astrophysics Data System (ADS)

    Yuan, Zhefan; Huang, Jingyi; Liu, Jing; Cheng, Sixue; Zhuo, Renxi; Li, Feng

    2011-08-01

    Polyethylene glycol detachable graft copolymer, mPEG-g-p(NAS-co-BMA), was synthesized by grafting 2-(ω-methoxy)PEGyl-1,3-dioxan-5-ylamine onto poly(N-(acryloyloxy)succinimide-co-butyl methacrylate). Pseudo in situ cross-linking of the mPEG-g-p(NAS-co-BMA) was performed in dimethylformamide phosphate buffer (v/v = 1/1) by an acid-labile diamine cross-linker bearing two symmetrical cyclic orthoesters. The cross-linked (CL) micelles with different contents of mPEG segments represented different morphologies. The CL micelles containing approximately one mPEG segment exhibited 'echini' morphology whereas the CL micelle with approximately three mPEG segments formed nanowires. The hydrolysis rate of the CL micelles is highly pH-dependent and much more rapid at mild acid than physiological conditions. Hydrolyzates of the CL micelles formed vesicles because new amphiphilic copolymers were formed. Paclitaxel (PTX) was successfully loaded into the CL micelles and a controlled and pH-dependent release behavior was observed. No obvious cytotoxicity was found for the CL micelles at concentration as high as 800 mg l - 1.

  6. Surfactant mediated synthesis of poly(acrylic acid) grafted xanthan gum and its efficient role in adsorption of soluble inorganic mercury from water.

    PubMed

    Pal, Abhijit; Majumder, Kunal; Bandyopadhyay, Abhijit

    2016-11-01

    Noble copolymers from xanthan gum (XG) and poly(acrylic acid) (PAA) were synthesised through surfactant mediated graft copolymerization. The copolymers were applied as a biosorbent for inorganic Hg(II) at higher concentration level (300ppm). The copolymers were characterized using different analytical techniques which showed, the grafting principally occurred across the amorphous region of XG. Measurement of zeta potential and hydrodynamic size indicated, the copolymers were strong polyanion and possessed greater hydrodynamic size (almost in all cases) than XG, despite a strong molecular degradation that took place simultaneously during grafting. In the dispersed form, all grades of the copolymer displayed higher adsorption capability than XG, however, the grade with maximum grafting produced the highest efficiency (68.03%). Manipulation produced further improvement in efficiency to 72.17% with the same copolymer after 75min at a pH of 5.0. The allowable biosorbent dose, however, was 1000ppm as determined from the experimental evidences. PMID:27516248

  7. Chitosan-based scaffolds for bone tissue engineering

    PubMed Central

    Levengood, Sheeny Lan; Zhang, Miqin

    2014-01-01

    Bone defects requiring grafts to promote healing are frequently occurring and costly problems in health care. Chitosan, a biodegradable, naturally occurring polymer, has drawn considerable attention in recent years as scaffolding material in tissue engineering and regenerative medicine. Chitosan is especially attractive as a bone scaffold material because it supports the attachment and proliferation of osteoblast cells as well as formation of mineralized bone matrix. In this review, we discuss the fundamentals of bone tissue engineering and the unique properties of chitosan as a scaffolding material to treat bone defects for hard tissue regeneration. We present the common methods for fabrication and characterization of chitosan scaffolds, and discuss the influence of material preparation and addition of polymeric or ceramic components or biomolecules on chitosan scaffold properties such as mechanical strength, structural integrity, and functional bone regeneration. Finally, we highlight recent advances in development of chitosan-based scaffolds with enhanced bone regeneration capability. PMID:24999429

  8. Guided bone regeneration by poly(lactic-co-glycolic acid) grafted hyaluronic acid bi-layer films for periodontal barrier applications.

    PubMed

    Park, Jung Kyu; Yeom, Junseok; Oh, Eun Ju; Reddy, Mallikarjuna; Kim, Jong Young; Cho, Dong-Woo; Lim, Hyun Pil; Kim, Nam Sook; Park, Sang Won; Shin, Hong-In; Yang, Dong Jun; Park, Kwang Bum; Hahn, Sei Kwang

    2009-11-01

    A novel protocol for the synthesis of biocompatible and degradation controlled poly(lactic-co-glycolic acid) grafted hyaluronic acid (HA-PLGA) was successfully developed for periodontal barrier applications. HA was chemically modified with adipic acid dihydrazide (ADH) in the mixed solvent of water and ethanol, which resulted in a high degree of HA modification up to 85 mol.%. The stability of HA-ADH to enzymatic degradation by hyaluronidase increased with ADH content in HA-ADH. When the ADH content in HA-ADH was higher than 80 mol.%, HA-ADH became soluble in dimethyl sulfoxide and could be grafted to the activated PLGA with N,N'-dicyclohexyl carbodiimide and N-hydroxysuccinimide. The resulting HA-PLGA was used for the preparation of biphasic periodontal barrier membranes in chloroform. According to in vitro hydrolytic degradation tests in phosphate buffered saline, HA-PLGA/PLGA blend film with a weight ratio of 1/2 degraded relatively slowly compared to PLGA film and HA coated PLGA film. Four different samples of a control, OSSIX(TM) membrane, PLGA film, and HA-PLGA/PLGA film were assessed as periodontal barrier membranes for the calvarial critical size bone defects in SD rats. Histological and histomorphometric analyses revealed that HA-PLGA/PLGA film resulted in the most effective bone regeneration compared to other samples with a regenerated bone area of 63.1% covering the bone defect area. PMID:19477304

  9. Nanoparticles of alkylglyceryl-dextran-graft-poly(lactic acid) for drug delivery to the brain: Preparation and in vitro investigation.

    PubMed

    Toman, Petr; Lien, Chun-Fu; Ahmad, Zeeshan; Dietrich, Susanne; Smith, James R; An, Qian; Molnár, Éva; Pilkington, Geoffrey J; Górecki, Darek C; Tsibouklis, John; Barbu, Eugen

    2015-09-01

    Poly(lactic acid), which has an inherent tendency to form colloidal systems of low polydispersity, and alkylglyceryl-modified dextran - a material designed to combine the non-immunogenic and stabilising properties of dextran with the demonstrated permeation enhancing ability of alkylglycerols - have been combined for the development of nanoparticulate, blood-brain barrier-permeating, non-viral vectors. To this end, dextran, that had been functionalised via treatment with epoxide precursors of alkylglycerol, was covalently linked to poly(lactic acid) using a carbodiimide cross-linker to form alkylglyceryl-modified dextran-graft-poly(lactic acid). Solvent displacement and electrospray methods allowed the formulation of these materials into nanoparticles having a unimodal size distribution profile of about 100-200nm and good stability at physiologically relevant pH (7.4). The nanoparticles were characterised in terms of hydrodynamic size (by Dynamic Light Scattering and Nanoparticle Tracking Analysis), morphology (by Scanning Electron Microscopy and Atomic Force Microscopy) and zeta potential, and their toxicity was evaluated using MTT and PrestoBlue assays. Cellular uptake was evidenced by confocal microscopy employing nanoparticles that had been loaded with the easy-to-detect Rhodamine B fluorescent marker. Transwell-model experiments employing mouse (bEnd3) and human (hCMEC/D3) brain endothelial cells revealed enhanced permeation (statistically significant for hCMEC/D3) of the fluorescent markers in the presence of the nanoparticles. Results of studies using Electric Cell Substrate Impedance Sensing suggested a transient decrease of the barrier function in an in vitro blood-brain barrier model following incubation with these nanoformulations. An in ovo study using 3-day chicken embryos indicated the absence of whole-organism acute toxicity effects. The collective in vitro data suggest that these alkylglyceryl-modified dextran-graft-poly(lactic acid) nanoparticles

  10. pH effect of coagulation bath on the characteristics of poly(acrylic acid)-grafted and poly(4-vinylpyridine)-grafted poly(vinylidene fluoride) microfiltration membranes.

    PubMed

    Ying, Lei; Zhai, Guangqun; Winata, A Y; Kang, E T; Neoh, K G

    2003-09-15

    The poly(acrylic acid)-graft-poly(vinylidene fluoride) (PAAc-g-PVDF) and poly(4-vinylpyridine)-graft-poly(vinylidene fluoride) (P4VP-g-PVDF) copolymers were obtained by thermally induced molecular graft copolymerization of acrylic acid (AAc) and 4-vinylpyridine (4VP), respectively, with the ozone-pretreated poly(vinylidene fluoride) (PVDF) in N-methyl-2-pyrrolidone (NMP) solution. Microfiltration (MF) membranes were prepared from the respective copolymers by phase inversion in aqueous media. The effects of pH of the coagulation bath on the physicochemical and morphological characteristics of the membranes were investigated. The surface compositions of the membranes were determined by X-ray photoelectron spectroscopy (XPS). The surface graft concentration of the AAc polymer for the PAAc-g-PVDF MF membrane increased with decreasing pH value of the coagulation bath. Completely opposite pH-dependent behavior was observed for the surface graft concentration of the 4VP polymer in the P4VP-g-PVDF MF membranes. A substantial increase in mean pore size was observed for the PAAc-g-PVDF MF membranes cast in basic coagulation baths of increasing pH. In the case of the P4VP-g-PVDF MF membranes, a substantial increase in mean pore size was observed for membranes cast in low pH (acidic) baths. The permeation rate of aqueous solutions through the PAAc-g-PVDF and P4VP-g-PVDF MF membranes exhibited a reversible dependence on the pH of the solution, with the membranes cast near the neutral pH exhibiting the highest sensitivity to changes in permeate pH. PMID:12962674

  11. Dorsal root ganglion-derived Schwann cells combined with poly(lactic-co-glycolic acid)/chitosan conduits for the repair of sciatic nerve defects in rats

    PubMed Central

    Zhao, Li; Qu, Wei; Wu, Yuxuan; Ma, Hao; Jiang, Huajun

    2014-01-01

    Schwann cells, nerve regeneration promoters in peripheral nerve tissue engineering, can be used to repair both the peripheral and central nervous systems. However, isolation and purification of Schwann cells are complicated by contamination with fibroblasts. Current reported measures are mainly limited by either high cost or complicated procedures with low cell yields or purity. In this study, we collected dorsal root ganglia from neonatal rats from which we obtained highly purified Schwann cells using serum-free melanocyte culture medium. The purity of Schwann cells (> 95%) using our method was higher than that using standard medium containing fetal bovine serum. The obtained Schwann cells were implanted into poly(lactic-co-glycolic acid)/chitosan conduits to repair 10-mm sciatic nerve defects in rats. Results showed that axonal diameter and area were significantly increased and motor functions were obviously improved in the rat sciatic nerve tissue. Experimental findings suggest that serum-free melanocyte culture medium is conducive to purify Schwann cells and poly(lactic-co-glycolic acid)/chitosan nerve conduits combined with Schwann cells contribute to restore sciatic nerve defects. PMID:25598778

  12. Effects of Local Administration of Boric Acid on Posterolateral Spinal Fusion with Autogenous Bone Grafting in a Rodent Model.

    PubMed

    Kömürcü, Erkam; Özyalvaçlı, Gülzade; Kaymaz, Burak; Gölge, Umut Hatay; Göksel, Ferdi; Cevizci, Sibel; Adam, Gürhan; Ozden, Raif

    2015-09-01

    Spinal fusion is among the most frequently applied spinal surgical procedures. The goal of the present study was to evaluate whether the local administration of boric acid (BA) improves spinal fusion in an experimental spinal fusion model in rats. Currently, there is no published data that evaluates the possible positive effects if the local administration of BA on posterolateral spinal fusion. Thirty-two rats were randomly divided into four independent groups: no material was added at the fusion area for group 1; an autogenous morselized corticocancellous bone graft was used for group 2; an autogenous morselized corticocancellous bone graft with boric acid (8.7 mg/kg) for group 3; and only boric acid was placed into the fusion area for group 4. The L4-L6 spinal segments were collected at week 6, and the assessments included radiography, manual palpation, and histomorphometry. A statistically significant difference was determined between the groups with regard to the mean histopathological scores (p = 0.002), and a paired comparison was made with the Mann-Whitney U test to detect the group/groups from which the difference originated. It was determined that only the graft + BA practice increased the histopathological score significantly with regard to the control group (p = 0.002). Whereas, there was no statistically significant difference between the groups in terms of the manual assessment of fusion and radiographic analysis (respectively p = 0.328 and p = 0.196). This preliminary study suggests that BA may clearly be useful as a therapeutic agent in spinal fusion. However, further research is required to show the most effective dosage of BA on spinal fusion, and should indicate whether BA effects spinal fusion in the human body. PMID:25728510

  13. Effect of zoledronate acid treatment on osseointegration and fixation of implants in autologous iliac bone grafts in ovariectomized rabbits.

    PubMed

    Qi, Mengchun; Hu, Jing; Li, Jianping; Li, Jinyuan; Dong, Wei; Feng, Xiaojie; Yu, Jing

    2012-01-01

    One main problem associated with alveolar bone augmentation in implant dentistry is resorption of grafted bone, which may be further compromised by systemic skeletal disorders such as osteoporosis. Zoledronate acid (ZOL) is the most potent bisphosphonate to treat osteoporosis and therefore it is hypothesized to be able to invert the negative effect of osteoporosis on osseointegration and fixation of dental implants in autologous bone grafts. In this study, 56 rabbits received bilateral ovariectomy (OVX) (40 rabbits) or sham operation (16 rabbits). Three months later, 8 animals from each group were sacrificed for bone mineral density (BMD) examination. Then the remaining animals underwent bilateral autologous iliac bone grafting with simultaneous implantation of titanium implants in tibiae and were divided into 5 groups (n=8): Sham, OVX, Loc-ZOL (local treatment), Sys-ZOL (systemic treatment) and Loc+Sys-ZOL (local plus systemic) group. At 3 months after implantation, all animals were sacrificed and specimens were harvested for examinations. Both BMD and histological examinations of femurs showed osteoporotic changes after ovariectomy, while systemic treatment with ZOL restored mineralized bone. Micro-CT examination demonstrated that OVX group showed significant decrease of mineralized bone and implant-bone contact when compared with sham control, whereas both systemic and local treatments of ZOL significantly increased mineralized bone and implant-bone contact in ovariectomized animals. However, the best effects were observed in Loc+Sys-ZOL group (combined use of ZOL) and most of bone indices were similar to (IBCR, p>0.05) or higher than (BV/TV, Conn.D and Tb.N) (p<0.01) those of the sham group, except Tb.Th, which was still significantly lower (p<0.01), and Tb.Sp, which was further decreased (p<0.01). The aforementioned effects were also confirmed by histomorphometric analysis of bone indices on implant-bone contact and mineralized bone. In addition, biomechanical

  14. Repair of rat cranial bone defect by using bone morphogenetic protein-2-related peptide combined with microspheres composed of polylactic acid/polyglycolic acid copolymer and chitosan.

    PubMed

    Li, Jingfeng; Jin, Lin; Wang, Mingbo; Zhu, Shaobo; Xu, Shuyun

    2015-08-01

    The effects of the transplanted bone morphogenetic protein-2 (BMP2) -related peptide P24 and rhBMP2 combined with poly(lactic-co-glycolic acid) (PLGA)/chitosan (CS) microspheres were investigated in promoting the repair of rat cranial bone defect. Forty white rats were selected and equally divided into four groups (group A: 1 μg of rhBMP2/PLGA/CS composite; group B: 3 mg of P24/PLGA/CS composite; group C: 0.5 μg of rhBMP2 + 1.5 mg of P24/PLGA/CS composite; group D: blank PLGA/CS material), and rat cranial bone defect models with a diameter of 5 mm were established. The materials were transplanted to the cranial bone defects. The animals were sacrificed on weeks 6 and 12 post-operation. Radiographic examinations (x-ray imaging and 3D CT scanning) and histological evaluations were performed. The repaired areas of cranial bone defects were measured, and the osteogenetic abilities of various materials were compared. Cranial histology, imaging, and repaired area measurements showed that the osteogenetic effects at two time points (weeks 6 and 12) in group C were better than those in groups A and B. The effects in groups A and B were similar. Group D achieved the worst repair effect of cranial bone defects, where a large number of fibrous connective tissues were observed. The PLGA/CS composite microspheres loaded with rhBMP2 and P24 had optimal concrescence and could mutually increase their osteogenesis capability. rhBMP2 + P24/PLGA/CS composite is a novel material for bone defect repair with stable activity to induce bone formation. PMID:26154695

  15. Chitosan-film enhanced chitosan nerve guides for long-distance regeneration of peripheral nerves.

    PubMed

    Meyer, Cora; Stenberg, Lena; Gonzalez-Perez, Francisco; Wrobel, Sandra; Ronchi, Giulia; Udina, Esther; Suganuma, Seigo; Geuna, Stefano; Navarro, Xavier; Dahlin, Lars B; Grothe, Claudia; Haastert-Talini, Kirsten

    2016-01-01

    Biosynthetic nerve grafts are developed in order to complement or replace autologous nerve grafts for peripheral nerve reconstruction. Artificial nerve guides currently approved for clinical use are not widely applied in reconstructive surgery as they still have limitations especially when it comes to critical distance repair. Here we report a comprehensive analysis of fine-tuned chitosan nerve guides (CNGs) enhanced by introduction of a longitudinal chitosan film to reconstruct critical length 15 mm sciatic nerve defects in adult healthy Wistar or diabetic Goto-Kakizaki rats. Short and long term investigations demonstrated that the CNGs enhanced by the guiding structure of the introduced chitosan film significantly improved functional and morphological results of nerve regeneration in comparison to simple hollow CNGs. Importantly, this was detectable both in healthy and in diabetic rats (short term) and the regeneration outcome almost reached the outcome after autologous nerve grafting (long term). Hollow CNGs provide properties likely leading to a wider clinical acceptance than other artificial nerve guides and their performance can be increased by simple introduction of a chitosan film with the same advantageous properties. Therefore, the chitosan film enhanced CNGs represent a new generation medical device for peripheral nerve reconstruction. PMID:26517563

  16. Bone Grafts

    MedlinePlus

    A bone graft transplants bone tissue. Surgeons use bone grafts to repair and rebuild diseased bones in your hips, knees, spine, and sometimes other bones and joints. Grafts can also repair bone loss caused by some ...

  17. Properties of starch-polyglutamic acid (PGA) graft copolymer prepared by microwave irradiation - the Fourier transform infrared spectroscopy (FTIR) and rheology studies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The rheological properties of waxy starch-'-polygutamic acid (PGA) graft copolymers were investigated. The starch-PGA copolymers absorbed water and formed gels, which exhibited concentration-dependent viscoelastic solid properties. Higher starch-PGA concentrations resulted in stronger viscoelastic p...

  18. Chitosan Dermal Substitute and Chitosan Skin Substitute Contribute to Accelerated Full-Thickness Wound Healing in Irradiated Rats

    PubMed Central

    Mohd Hilmi, Abu Bakar; Halim, Ahmad Sukari; Jaafar, Hasnan; Asiah, Abu Bakar; Hassan, Asma

    2013-01-01

    Wounds with full-thickness skin loss are commonly managed by skin grafting. In the absence of a graft, reepithelialization is imperfect and leads to increased scar formation. Biomaterials can alter wound healing so that it produces more regenerative tissue and fewer scars. This current study use the new chitosan based biomaterial in full-thickness wound with impaired healing on rat model. Wounds were evaluated after being treated with a chitosan dermal substitute, a chitosan skin substitute, or duoderm CGF. Wounds treated with the chitosan skin substitute showed the most re-epithelialization (33.2 ± 2.8%), longest epithelial tongue (1.62 ± 0.13 mm), and shortest migratory tongue distance (7.11 ± 0.25 mm). The scar size of wounds treated with the chitosan dermal substitute (0.13 ± 0.02 cm) and chitosan skin substitute (0.16 ± 0.05 cm) were significantly decreased (P < 0.05) compared with duoderm (0.45 ± 0.11 cm). Human leukocyte antigen (HLA) expression on days 7, 14, and 21 revealed the presence of human hair follicle stem cells and fibroblasts that were incorporated into and surviving in the irradiated wound. We have proven that a chitosan dermal substitute and chitosan skin substitute are suitable for wound healing in full-thickness wounds that are impaired due to radiation. PMID:24324974

  19. Chitosan dermal substitute and chitosan skin substitute contribute to accelerated full-thickness wound healing in irradiated rats.

    PubMed

    Mohd Hilmi, Abu Bakar; Halim, Ahmad Sukari; Jaafar, Hasnan; Asiah, Abu Bakar; Hassan, Asma

    2013-01-01

    Wounds with full-thickness skin loss are commonly managed by skin grafting. In the absence of a graft, reepithelialization is imperfect and leads to increased scar formation. Biomaterials can alter wound healing so that it produces more regenerative tissue and fewer scars. This current study use the new chitosan based biomaterial in full-thickness wound with impaired healing on rat model. Wounds were evaluated after being treated with a chitosan dermal substitute, a chitosan skin substitute, or duoderm CGF. Wounds treated with the chitosan skin substitute showed the most re-epithelialization (33.2 ± 2.8%), longest epithelial tongue (1.62 ± 0.13 mm), and shortest migratory tongue distance (7.11 ± 0.25 mm). The scar size of wounds treated with the chitosan dermal substitute (0.13 ± 0.02 cm) and chitosan skin substitute (0.16 ± 0.05 cm) were significantly decreased (P < 0.05) compared with duoderm (0.45 ± 0.11 cm). Human leukocyte antigen (HLA) expression on days 7, 14, and 21 revealed the presence of human hair follicle stem cells and fibroblasts that were incorporated into and surviving in the irradiated wound. We have proven that a chitosan dermal substitute and chitosan skin substitute are suitable for wound healing in full-thickness wounds that are impaired due to radiation. PMID:24324974

  20. Interactions at the mild steel acid solution interface in the presence of O-fumaryl-chitosan: Electrochemical and surface studies.

    PubMed

    Sangeetha, Y; Meenakshi, S; Sundaram, C Sairam

    2016-01-20

    The performance of synthesised O-fumaryl-chitosan (OFC) as corrosion inhibitor for mild steel in 1M HCl has been evaluated through various studies. The initial screening by weight loss method revealed the good inhibition efficiency by the inhibitor. Thermodynamic and kinetic parameters have been calculated and discussed. The mode of adsorption is physical in nature and it follows Langmuir adsorption isotherm. Electrochemical measurements supported the inhibition of mild steel by the fumaryl derivative of chitosan. Polarisation studies provided the information that the inhibition is of mixed type. The formation of inhibitor film is assured by surface morphological studies with Scanning electron microscopy (SEM) and Atomic force microscopy (AFM). The mechanism of inhibition is derived from the Fourier-transform infrared (FTIR) spectroscopy and zero charge potential measurement. The adsorbed film is characterised using FTIR and X-ray diffraction studies (XRD). PMID:26572326

  1. Effect of l-lysine-assisted surface grafting for nano-hydroxyapatite on mechanical properties and in vitro bioactivity of poly(lactic acid-co-glycolic acid).

    PubMed

    Liuyun, Jiang; Lixin, Jiang; Chengdong, Xiong; Lijuan, Xu; Ye, Li

    2016-01-01

    It is promising and challenging to study surface modification for nano-hydroxyapatite to improve the dispersion and enhance the mechanical properties and bioactivity of poly(lactic acid-co-glycolic acid). In this paper, we designed an effective new surface grafting with the assist of l-lysine for nano-hydroxyapatite, and the nano-hydroxyapatite surface grafted with the assist of l-lysine (g-nano-hydroxyapatite) was incorporated into poly(lactic acid-co-glycolic acid) to develop a series of g-nano-hydroxyapatite/poly(lactic acid-co-glycolic acid) nano-composites. The surface modification reaction for nano-hydroxyapatite, the mechanical properties, and in vitro human osteoblast-like cell (MG-63) response were characterized and investigated by Fourier transformation infrared, thermal gravimetric analysis, dispersion test, electromechanical universal tester, differential scanning calorimeter measurements, and in vitro cells culture experiment. The results showed that the grafting amount on the surface of nano-hydroxyapatite was enhanced with the increase of l-lysine, and the dispersion of nano-hydroxyapatite was improved more, so that it brought about better promotion crystallization and more excellent mechanical enhancement effect for poly(lactic acid-co-glycolic acid), comparing with the unmodified nano-hydroxyapatite. Moreover, the cells' attachment and proliferation results confirmed that the incorporation of the g-nano-hydroxyapatite into poly(lactic acid-co-glycolic acid) exhibited better biocompatibility than poly(lactic acid-co-glycolic acid). The above results indicated that the new surface grafting with the assist of l-lysine for nano-hydroxyapatite was an ideal novel surface modification method, which brought about better mechanical enhancement effect and in vitro bioactivity for poly(lactic acid-co-glycolic acid) with adding higher g-nano-hydroxyapatite content, suggesting it had a great potential to be used as bone fracture internal fixation materials

  2. 2-Acrylamido-2-methyl-1-propanesulfonic Acid Grafted Poly(vinylidene fluoride-co-hexafluoropropylene)-Based Acid-/Oxidative-Resistant Cation Exchange for Membrane Electrolysis.

    PubMed

    Pandey, Ravi P; Das, Arindam K; Shahi, Vinod K

    2015-12-30

    For developing acid-/oxidative-resistant aliphatic-polymer-based cation-exchange membrane (CEM), macromolecular modification of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP) was carried out by controlled chemical grafting of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS). To introduce the unsaturation suitable for chemical grafting, dehydrofluorination of commercially available PVDF-co-HFP was achieved under alkaline medium. Sulfonated copolymer (SCP) was prepared by the free radical copolymerization of dehydofluorinated PVDF-co-HFP (DHPVDF-co-HFP) and AMPS in the presence of free radical initiator. Prepared SCP-based CEMs were analyzed for their morphological characteristics, ion-exchange capacity (IEC), water uptake, conductivity, and stabilities (mechanical, chemical, and thermal) in comparison with state-of-art Nafion117 membrane. High bound water content avoids the membrane dehydration, and most optimal (SCP-1.33) membrane exhibited about ∼2.5-fold high bound water content in comparison with that of Nafion117 membrane. Bunsen reaction of iodine-sulfur (I-S) was successfully performed by direct-contact-mode membrane electrolysis in a two-compartment electrolytic cell using different SCP membranes. High current efficiency (83-99%) confirmed absence of any side reaction and 328.05 kJ mol-H2(-1) energy was required for to produce 1 mol of H2 by electrolytic cell with SCP-1.33 membrane. In spite of low conductivity for reported SCP membrane in comparison with that of Nafion117 membrane, SCP-1.33 membrane was assessed as suitable candidate for electrolysis because of its low-cost nature and excellent stabilities in highly acidic environment may be due to partial fluorinated segments in the membrane structure. PMID:26642107

  3. Coloration of cotton fibers using nano chitosan.

    PubMed

    Wijesena, Ruchira N; Tissera, Nadeeka D; de Silva, K M Nalin

    2015-12-10

    A method of coloration of cotton fabrics with nano chitosan is proposed. Nano chitosan were prepared using crab shell chitin nanofibers through alkaline deacetylation process. Average nano fiber diameters of nano chitosan were 18 nm to 35 nm and the lengths were in the range of 0.2-1.3 μm according to the atomic force microscope study. The degree of deacetylation of the material was found to be 97.3%. The prepared nano chitosan dyed using acid blue 25 (2-anthraquinonesulfonic acid) and used as the coloration agent for cotton fibers. Simple wet immersion method was used to color the cotton fabrics by nano chitosan dispersion followed by acid vapor treatment. Scanning electron microscope and atomic force microscope study of the treated cotton fiber revealed that the nano chitosan were consistently deposited on the cotton fiber surface and transformed in to a thin polymer layer upon the acid vapor treatment. The color strength of the dyed fabrics could be changed by changing the concentration of dyed nano chitosan dispersion. PMID:26428115

  4. Targeted delivery of small interfering RNA to colon cancer cells using chitosan and PEGylated chitosan nanoparticles.

    PubMed

    Rudzinski, Walter E; Palacios, Adriana; Ahmed, Abuzar; Lane, Michelle A; Aminabhavi, Tejraj M

    2016-08-20

    Small interfering RNA (siRNA) molecules specifically target messenger RNA species, decreasing intracellular protein levels. β-Catenin protein concentrations are increased in 70-80% of colon tumors, promoting tumor progression. Chitosan exhibits low levels of toxicity and can be transported across mucosal membranes; therefore, our objective was to develop chitosan and poly(ethylene glycol)-grafted (PEGylated) chitosan nanoparticles, 100-150nm in diameter, encapsulating anti-β-catenin siRNA for transfection into colon cancer cells. Encapsulation efficiencies up to 97% were observed. Confocal microscopy visualized the entry of fluorescently-tagged siRNA into cells. Western blot analysis showed that both chitosan and PEGylated chitosan nanoparticles containing anti-β-catenin siRNA decreased β-catenin protein levels in cultured colon cancer cells. These results indicate that nanoparticles made with chitosan and PEGylated chitosan can successfully enter colon cancer cells and decrease the level of a protein that promotes tumor progression. These or similar nanoparticles may prove beneficial for the treatment of colon cancer in humans. PMID:27178938

  5. Bioresorbable bone graft substitutes of different osteoconductivities: a histologic evaluation of osteointegration of poly(propylene glycol-co-fumaric acid)-based cement implants in rats.

    PubMed

    Lewandrowski, K U; Gresser, J D; Wise, D L; Trantol, D J

    2000-04-01

    Bioresorbable bone graft substitutes may significantly reduce the disadvantages associated with autografts, allografts and other synthetic materials currently used in bone graft procedures. We investigated the biocompatibility and osteointegration of a bioresorbable bone graft substitute made from the unsaturated polyester poly(propylene-glycol-co-fumaric acid), or simply poly(propylene fumarate), PPF, which is crosslinked in the presence of soluble and insoluble calcium filler salts. Four sets of animals each having three groups of 8 were evaluated by grouting bone graft substitutes of varying compositions into 3-mm holes that were made into the anteromedial tibial metaphysis of rats. Four different formulations varying as to the type of soluble salt filler employed were used: set 1--calcium acetate, set 2--calcium gluconate, set 3--calcium propionate, and set 4--control with hydroxapatite, HA, only. Animals of each of the three sets were sacrificed in groups of 8 at postoperative week 1, 3, and 7. Histologic analysis revealed that in vivo biocompatibility and osteointegration of bone graft substitutes was optimal when calcium acetate was employed as a soluble salt filler. Other formulations demonstrated implant surface erosion and disintegration which was ultimately accompanied by an inflammatory response. This study suggested that PPF-based bone graft substitutes can be designed to provide an osteoconductive pathway by which bone will grow in faster because of its capacity to develop controlled porosities in vivo. Immediate applicability of this bone graft substitute, the porosity of which can be tailored for the reconstruction of defects of varying size and quality of the recipient bed, is to defects caused by surgical debridement of infections, previous surgery, tumor removal, trauma, implant revisions and joint fusion. Clinical implications of the relation between developing porosity, resulting osteoconduction, and bone repair in vivo are discussed. PMID

  6. Enhanced in Vitro Mineralization and in Vivo Osteogenesis of Composite Scaffolds through Controlled Surface Grafting of L-Lactic Acid Oligomer on Nanohydroxyapatite.

    PubMed

    Wang, Zongliang; Xu, Yang; Wang, Yu; Ito, Yoshihiro; Zhang, Peibiao; Chen, Xuesi

    2016-03-14

    Nanocomposite of hydroxyapatite (HA) surface grafted with L-lactic acid oligomer (LAc oligomer) (op-HA) showed improved interface compatibility, mechanical property, and biocompatibility in our previous study. In this paper, composite scaffolds of op-HA with controlled grafting different amounts of LAc oligomer (1.1, 5.2, and 9.1 wt %) were fabricated and implanted to repair rabbit radius defects. The dispersion of op-HA nanoparticles was more uniform than n-HA in chloroform and nanocomposites scaffold. Calcium and phosphorus exposure, in vitro biomineralization ability, and cell proliferation were much higher in the op-HA1.1 wt %/PLGA scaffolds than the other groups. The osteodifferentiation and bone fusion in animal tests were significantly enhanced for op-HA5.2 wt %/PLGA scaffolds. The results indicated that the grafted LAc oligomer of 5.2 or 9.1 wt %, which formed a barrier layer on the HA surface, prevented the exposure of nucleation sites. The shielded nucleation sites of op-HA particles (5.2 wt %) might be easily exposed as the grafted LAc oligomer was decomposed easily by enzyme systems in vivo. Findings from this study have revealed that grafting 1.1 wt % amount of LAc oligomer on hydroxyapatite could improve in vitro mineralization, and 5.2 wt % could promote in vivo osteogenesis capacity of composite scaffolds. PMID:26821731

  7. Synthesis and Characterization of Poly(lactic-co-glycolic) Acid Nanoparticles-Loaded Chitosan/Bioactive Glass Scaffolds as a Localized Delivery System in the Bone Defects

    PubMed Central

    Nazemi, K.; Moztarzadeh, F.; Jalali, N.; Asgari, S.; Mozafari, M.

    2014-01-01

    The functionality of tissue engineering scaffolds can be enhanced by localized delivery of appropriate biological macromolecules incorporated within biodegradable nanoparticles. In this research, chitosan/58S-bioactive glass (58S-BG) containing poly(lactic-co-glycolic) acid (PLGA) nanoparticles has been prepared and then characterized. The effects of further addition of 58S-BG on the structure of scaffolds have been investigated to optimize the characteristics of the scaffolds for bone tissue engineering applications. The results showed that the scaffolds had high porosity with open pores. It was also shown that the porosity decreased with increasing 58S-BG content. Furthermore, the PLGA nanoparticles were homogenously distributed within the scaffolds. According to the obtained results, the nanocomposites could be considered as highly bioactive bone tissue engineering scaffolds with the potential of localized delivery of biological macromolecules. PMID:24949477

  8. Synthesis, characterization, and antifungal activity of novel quaternary chitosan derivatives.

    PubMed

    Li, Rongchun; Guo, Zhanyong; Jiang, Pingan

    2010-09-01

    Three novel quaternary chitosan derivatives were successfully synthesized by reaction of chloracetyl chitosan (CACS) with pyridine (PACS), 4-(5-chloro-2-hydroxybenzylideneamino)-pyridine (CHPACS), and 4-(5-bromo-2-hydroxybenzylideneamino)-pyridine (BHPACS). The chemical structure of the prepared chitosan derivatives was confirmed by Fourier transform infrared (FT-IR) and (13)C nuclear magnetic resonance ((13)C NMR) and their antifungal activity against Cladosporium cucumerinum, Monilinia fructicola, Colletotrichum lagenarium, and Fusarium oxysporum was assessed. Comparing with the antifungal activity of chitosan, CACS, and PACS, CHPACS and BHPACS exhibited obviously better inhibitory effects, which should be related to the synergistic reaction of chitosan itself with the grafted 2-[4-(5-chloro-2-hydroxybenzylideneamino)-pyridyl]acetyl and 2-[4-(5-bromo-2-hydroxybenzylideneamino)-pyridyl]acetyl. PMID:20615498

  9. Design and evaluation of an intravesical delivery system for superficial bladder cancer: preparation of gemcitabine HCl-loaded chitosan–thioglycolic acid nanoparticles and comparison of chitosan/poloxamer gels as carriers

    PubMed Central

    Ay Şenyiğit, Zeynep; Karavana, Sinem Yaprak; İlem-Özdemir, Derya; Çalışkan, Çağrı; Waldner, Claudia; Şen, Sait; Bernkop-Schnürch, Andreas; Baloğlu, Esra

    2015-01-01

    This study aimed to develop an intravesical delivery system of gemcitabine HCl for superficial bladder cancer in order to provide a controlled release profile, to prolong the residence time, and to avoid drug elimination via urination. For this aim, bioadhesive nanoparticles were prepared with thiolated chitosan (chitosan–thioglycolic acid conjugate) and were dispersed in bioadhesive chitosan gel or in an in situ gelling poloxamer formulation in order to improve intravesical residence time. In addition, nanoparticle-loaded gels were diluted with artificial urine to mimic in vivo conditions in the bladder and were characterized regarding changes in gel structure. The obtained results showed that chitosanthioglycolic acid nanoparticles with a mean diameter of 174.5±3.762 nm and zeta potential of 32.100±0.575 mV were successfully developed via ionotropic gelation and that the encapsulation efficiency of gemcitabine HCl was nearly 20%. In vitro/ex vivo characterization studies demonstrated that both nanoparticles and nanoparticle-loaded chitosan and poloxamer gels might be alternative carriers for intravesical administration of gemcitabine HCl, prolonging its residence time in the bladder and hence improving treatment efficacy. However, when the gel formulations were diluted with artificial urine, poloxamer gels lost their in situ gelling properties at body temperature, which is in conflict with the aimed formulation property. Therefore, 2% chitosan gel formulation was found to be a more promising carrier system for intravesical administration of nanoparticles. PMID:26508855

  10. Microspheres prepared with different co-polymers of poly(lactic-glycolic acid) (PLGA) or with chitosan cause distinct effects on macrophages.

    PubMed

    Bitencourt, Claudia da Silva; Silva, Letícia Bueno da; Pereira, Priscilla Aparecida Tartari; Gelfuso, Guilherme Martins; Faccioli, Lúcia Helena

    2015-12-01

    Microencapsulation of bioactive molecules for modulating the immune response during infectious or inflammatory events is a promising approach, since microspheres (MS) protect these labile biomolecules against fast degradation, prolong the delivery over longer periods of time and, in many situations, target their delivery to site of action, avoiding toxic side effects. Little is known, however, about the influence of different polymers used to prepare MS on macrophages. This paper aims to address this issue by evaluating in vitro cytotoxicity, phagocytosis profile and cytokines release from alveolar macrophages (J-774.1) treated with MS prepared with chitosan, and four different co-polymers of PLGA [poly (lactic-co-glycolic acid)]. The five MS prepared presented similar diameter and zeta potential each other. Chitosan-MS showed to be cytotoxic to J-774.1 cells, in contrast to PLGA-MS, which were all innocuous to this cell linage. PLGA 5000-MS was more efficiently phagocytized by macrophages compared to the other MS tested. PLGA 5000-MS and 5002-MS induced significant production of TNF-α, while 5000-MS, 5004-MS and 7502-MS decreased spontaneous IL-6 release. Nevertheless, only PLGA 5002-MS induced significant NFkB/SEAP activation. These findings together show that MS prepared with distinct PLGA co-polymers are differently recognized by macrophages, depending on proportion of lactic and glycolic acid in polymeric chain, and on molecular weight of the co-polymer used. Selection of the most adequate polymer to prepare a microparticulate drug delivery system to modulate immunologic system may take into account, therefore, which kind of immunomodulatory response is more adequate for the required treatment. PMID:26497115

  11. Insights into and relative effect of chitosan-H, chitosan-H-propolis, chitosan-H-propolis-nystatin and chitosan-H-nystatin on dentine bond strength

    PubMed Central

    Perchyonok, Victoria Tamara; Zhang, Shengmiao; Grobler, Sias R.; Oberholzer, Theunis G.

    2013-01-01

    Objective: The purpose of the study was to design and evaluate novel functional chitosan hydrogels (chitosan-H-propolis, chitosan-H-propolis-nystatin and chitosan-H-nystatin) by using the chitosan-H polymer as “dual function restorative materials”. Materials and Methods: The nystatin/antioxidant carrier gel was prepared by dispersion of the corresponding component in glycerol and 3% acetic acid with 5% chitosan gelling agent was then added to the dispersion with continuous mixing. The natural bio-adhesive functionalized chitosan hydrogels were combined with built in drug delivery system and bio-actives such as propolis in order to increase the dentin bond strength capacity and maintain therapeutic properties of the alternative drug delivery system. The surface morphology, release behaviors (physiological pH and also in acidic conditions), stability of nystatin:antioxidant:chitosan and the effect of the hydrogels on the shear bond strength of dentin were also evaluated. Statistical Analysis Used: Non-parametric ANOVA test was used to asses significance of higher shear bond values than dentine treated or not treated with phosphoric acid. Results: The release of both nystatin and propolis confer the added benefit of dual action of a functional therapeutic delivery when comparing the newly designed chitosan-based hydrogel restorative materials to commercially available nystatin alone. Neither the release of nystatin nor the antioxidant stability was affected by storage. Chitosan-H, chitosan-propolis, chitosan-nystatin and chitosan-nystatin-propolis treated dentine gives significantly (P < 0.05) higher shear bond values (P < 0.05) than dentine treated or not treated with phosphoric acid. Conclusion: The added benefits of their unique functionality involve increased dentin adhesive bond strengths (after 24 h and after 6 months) and positive influence on the nystatin release. Nystatin was a model therapeutic agent, evaluating the concept of using functional materials

  12. Chitosan Fibers Modified with HAp/β–TCP Nanoparticles

    PubMed Central

    Wawro, Dariusz; Pighinelli, Luciano

    2011-01-01

    This paper describes a method for preparing chitosan fibers modified with hydroxyapatite (HAp), tricalcium phosphate (β-TCP), and HAp/β-TCP nanoparticles. Fiber-grade chitosan derived from the northern shrimp (Pandalus borealis) and nanoparticles of tricalcium phosphate (β-TCP) and hydroxyapatite (HAp) suspended in a diluted chitosan solution were used in the investigation. Diluted chitosan solution containing nanoparticles of Hap/β-TCP was introduced to a 5.16 wt% solution of chitosan in 3.0 wt% acetic acid. The properties of the spinning solutions were examined. Chitosan fibers modified with nanoparticles of HAp/β-TCP were characterized by a level of tenacity and calcium content one hundred times higher than that of regular chitosan fibers. PMID:22174598

  13. A Chitosan Derivative Containing Both Carboxylic Acid and Quaternary Ammonium Moieties for the Synthesis of Cyclic Carbonates.

    PubMed

    Besse, Vincent; Illy, Nicolas; David, Ghislain; Caillol, Sylvain; Boutevin, Bernard

    2016-08-23

    Chitosan, a renewable feedstock, is modified and used as a catalytic support in the presence of potassium iodide. The system is highly efficient towards the incorporation of carbon dioxide (CO2 ) into epoxides. It demonstrates very good thermal stability and is recyclable more than five times without loss of activity. The optimal reaction conditions were determined using allylglycidyl ether as a model and extended to a wide range of other epoxides. Cyclic carbonates were obtained with very high yield in a few hours under mild conditions (2-7 bar≈0.2-0.7 MPa, 80 °C) and no solvent. PMID:27440310

  14. Synthesis and characterization of copolymer materials from chitosan and polyethylene glycol: Evaluation of potential for use in man-made blood vessels; and modeling of cell-material dynamic interactions

    NASA Astrophysics Data System (ADS)

    Zhong, Jingfang

    2005-11-01

    Blood vessel may have multi-layer structure with one layer offering the necessary mechanical properties, and the most inner layer offering blood compatibility. One goal of the research was to get some basic information about the in-vivo blood interaction and degradation properties of 3 types of modified chitosan materials: chitosan-g-PEG with 54.2% PEG, chitosan ionically bound with heparin, and chitosan crosslinked by sebacic acid and ionically bound with heparin. For studying the in-vivo blood interaction properties, the materials were processed in the way of mimicking blood vessels as two-layer structure, with outer layer as porous structure, and inner layer as smooth dense structure that were made from one of the 3 types of materials. They were implanted into rats to replace part of blood vessels, and the results of blood vessel replacement were observed. In recent studies, chitosan has been found to be a promising base material for a number of tissue engineering applications. The goal of this investigation was to modify the elastic modulus of chitosan material without loss of strength to make chitosan material have different suitable elastic modulus for different biomedical applications. PEG side chains were grafted onto chitosan to make copolymer material. Copolymer's mechanical, micro-structural, cell interaction properties were investigated. It was found that with increasing PEG content, the elastic modulus decreased because the crystal structure in chitosan was destroyed by the grafted PEG chains. Copolymer showed effect on inhibiting smooth muscle cell growth comparing with unmodified chitosan. When PEG content changed only in the small range of 0--10%, the changes of both mechanical properties and cell interaction properties were already very significant. 3 dynamic models addressing both receptor and ligand mobility, and various reaction geometries were developed. Model was validated with published data on interaction between lymphocytes and membrane

  15. Improving the degradation behavior and in vitro biological property of nano-hydroxyapatite surface- grafted with the assist of citric acid.

    PubMed

    Jiang, Liuyun; Jiang, Lixin; Xiong, Chengdong; Su, Shengpei

    2016-10-01

    To obtain ideal nano-hydroxyapatite(n-HA) filler for poly(lactide-co-glycolide) (PLGA), a new surface-grafting with the assist of citric acid for nano-hydroxyapatite (n-HA) was designed, and the effect of n-HA surface-grafted with or without citric acid on in vitro degradation behavior and cells viability was studied by the experiments of soaking in simulated body fluid (SBF) and incubating with human osteoblast-like cells (MG-63). The change of pH value, tensile strength reduction, the surface deposits, cells attachment and proliferation of samples during the soaking and incubation were investigated by means of pH meter, electromechanical universal tester, scanning electron microscope (SEM) coupled with energy-dispersive spectro-scopy (EDS), fluorescence microscope and MTT method. The results showed that the introduction of citric acid not only delayed the strength reduction during the degradation by inhibiting the detachment of n-HA from PLGA, but also endowed it better cell attachment and proliferation, suggesting that the n-HA surface-grafted with the assist of citric acid was an important bioactive ceramic fillers for PLGA used as bone materials. PMID:27343845

  16. Morphology characterization and biocompatibility study of PLLA (Poly-L-Llactid-Acid) coating chitosan as stent for coronary heart disease

    NASA Astrophysics Data System (ADS)

    Widiyanti, Prihartini; Paramadini, Adanti W.; Jabbar, Hajria; Fatimah, Inas; Nisak, Fadila N. K.; Puspitasari, Rahma A.

    2016-03-01

    Cardiovascular disease is a global disease with high urgency. In the severe case of coronary heart disease while a blockage in the coronary arteries reach 75% or more, the patient required stent implantation. Stents are made of metal which has many limitations that can lead to blood clots and stent incompatibility toward the size of the blood vessels. There is a metal stent replacement solution that made from polymer material which is biocompatible. PLLA also has biocompatibility and good mechanical strength. PLLA stent will be coated with chitosan as a candidate for drug-coated stents which is able to work as a drug carrier. The aim of this study is to know the morphology information and biocompability status of PLLA coating chitosan as candidate of heart stent. Morphological results using SEM showed a smooth surface structure which reinforced clinical standard of stent material. Results of cytotoxicity test by MTT Assay method showed that the result of four samples in this experiment living cells is reached 90% which is non toxic and safe to use in the human body. %). The conclusion of this study is PLLA is polymer has potency to be used as stent material.

  17. Radiation-grafting of thermo- and pH-responsive poly(N-vinylcaprolactam-co-acrylic acid) onto silicone rubber and polypropylene films for biomedical purposes

    NASA Astrophysics Data System (ADS)

    Ferraz, Caroline C.; Varca, Gustavo H. C.; Ruiz, Juan-Carlos; Lopes, Patricia S.; Mathor, Monica B.; Lugão, Ademar B.; Bucio, Emilio

    2014-04-01

    This work focuses on the effects of gamma-ray irradiation conditions on the stimuli-responsiveness of polypropylene (PP) films and silicone (SR) rubber substrates grafted with N-vinylcaprolactam (NVCL) and acrylic acid (AAc). PP films and SR rubber were modified by simultaneous polymerization and grafting of NVCL and AAc, using pre-irradiation oxidative method at a dose rate of 12.23 kGy h-1 and doses ranging from 5 to 70 kGy. NVCL and AAc solutions (1/1, v/v) at 50% monomer concentration (v/v) in toluene were added to the sample substrates, degassed, sealed and heated at 60 and 70 °C for 12 h. After grafting, the samples were soaked in ethanol and distilled water for 24 h successively, followed by drying under vacuum. Samples were characterized by FTIR-ATR, DSC and swelling measurements. Critical points (pH critical or LCST) of grafts were obtained in a pH-environment (pH ranges from 2.2 to 9) and in a thermo-environment (temperature ranges from 22 to 50 °C). Cytotoxicity evaluation was performed using fibroblast BALB/c 3T3 cells. The relationship between NVCL-co-AAc grafting and radiation dose was different for each substrate, PP and SR. At 50% NVCL/AAc concentration in toluene, grafting values were higher for SR than for PP. Despite the fact that PP-g-(NVCL-co-AAc) membrane presented a cytotoxic profile at the highest experimental concentration assayed, cytotoxicity evaluation revealed noncytotoxic profiles for the membranes synthesized highlighting their applications for biomedical purposes.

  18. Functional modification of chitosan for biomedical application

    NASA Astrophysics Data System (ADS)

    Tang, Ruogu

    Chitosan is a linear polysaccharide. Normally commercial chitosan consists of randomly distributed beta-(1-4)-linked D-glucosamine (deacetylated proportion) and N-acetyl-D-glucosamine (acetylated proportion) together. Chitosan has been proved to be a multifunctional biopolymer that presents several unique properties due to free amino groups in the repeating unit therefore chitosan has been widely applied in various areas. To be specific, provided by the excellent biocompatibility, chitosan is expected to be used in biological and medical applications including wound dressing, implants, drug carrier/delivery, etc. In this thesis, we worked on chitosan functionalization for biomedical application. The thesis are composed of three parts: In the first part, we focused on modifying the chitosan thin film, chemically introducing the nitric oxide functional groups on chitosan film. We covalently bonded small molecule diazeniumdiolates onto the chitosan films and examined the antimicrobial function and biocompatibility. Commercial chitosan was cast into films from acidic aqueous solutions. Glutaraldehyde reacted with the chitosan film to introduce aldehyde groups onto the chitosan film (GA-CS film). GA-CS reacted with a small molecule NO donor, NOC-18, to covalently immobilize NONO groups onto the polymer (NO-CS film). The-CHO and [NONO] group were verified by FT IR, UV and Griess reagent. The NO releasing rate in aqueous solution and and thermal stability were studied quantitatively to prove its effectiveness. A series of antimicrobial tests indicated that NO-CS films have multiple functions: 1. It could inhibit the bacteria growth in nutrient rich environment; 2. It could directly inactivate bacteria and biofilm; 3. It could reduce the bacteria adherence on the film surface as well as inhibit biofilm formation. In addition, the NO-CS film was proved to be biocompatible with cell and it was also compatible with other antibiotics like Amoxicillin. In the second part, we

  19. Controlled-release of tetracycline and lovastatin by poly(d,l-lactide-co-glycolide acid)-chitosan nanoparticles enhances periodontal regeneration in dogs

    PubMed Central

    Lee, Bor-Shiunn; Lee, Chien-Chen; Wang, Yi-Ping; Chen, Hsiao-Jan; Lai, Chern-Hsiung; Hsieh, Wan-Ling; Chen, Yi-Wen

    2016-01-01

    Chronic periodontitis is characterized by inflammation of periodontal tissues, leading to bone resorption and tooth loss. The goal of treatment is to regenerate periodontal tissues including bone and cementum lost as a consequence of disease. The local delivery of tetracycline was proven to be effective in controlling localized periodontal infection without apparent side effects. Previous studies suggested that lovastatin has a significant role in new bone formation; however, the local delivery of lovastatin might enhance its therapeutic effects. A number of local delivery devices have been developed recently, including poly(d,l-lactide-co-glycolide acid) (PLGA) nanoparticles. The aim of this study was to develop a local delivery device, PLGA-lovastatin-chitosan-tetracycline nanoparticles, which allows the sequential release of tetracycline and lovastatin to effectively control local infection and promote bone regeneration in periodontitis. The size and microstructure of nanoparticles were examined by transmission electron microscopy, Nanoparticle Size Analyzer, and Fourier transform infrared spectroscopy. The release of tetracycline and lovastatin was quantified using a UV-Vis spectrophotometer. Furthermore, the cytotoxic effect and alkaline phosphatase activity of the nanoparticles in osteoblast cell cultures as well as antibacterial activity against periodontal pathogens were investigated. Finally, the bone regeneration potential of PLGA nanoparticles in three-walled defects in beagle dogs was investigated. The results indicated that PLGA-lovastatin-chitosan-tetracycline nanoparticles showed good biocompatibility, antibacterial activity, and increased alkaline phosphatase activity. The volumetric analysis from micro-CT revealed significantly increased new bone formation in defects filled with nanoparticles in dogs. This novel local delivery device might be useful as an adjunctive treatment in periodontal regenerative therapy. PMID:26848264

  20. Controlled-release of tetracycline and lovastatin by poly(D,L-lactide-co-glycolide acid)-chitosan nanoparticles enhances periodontal regeneration in dogs.

    PubMed

    Lee, Bor-Shiunn; Lee, Chien-Chen; Wang, Yi-Ping; Chen, Hsiao-Jan; Lai, Chern-Hsiung; Hsieh, Wan-Ling; Chen, Yi-Wen

    2016-01-01

    Chronic periodontitis is characterized by inflammation of periodontal tissues, leading to bone resorption and tooth loss. The goal of treatment is to regenerate periodontal tissues including bone and cementum lost as a consequence of disease. The local delivery of tetracycline was proven to be effective in controlling localized periodontal infection without apparent side effects. Previous studies suggested that lovastatin has a significant role in new bone formation; however, the local delivery of lovastatin might enhance its therapeutic effects. A number of local delivery devices have been developed recently, including poly(D,L-lactide-co-glycolide acid) (PLGA) nanoparticles. The aim of this study was to develop a local delivery device, PLGA-lovastatin-chitosan-tetracycline nanoparticles, which allows the sequential release of tetracycline and lovastatin to effectively control local infection and promote bone regeneration in periodontitis. The size and microstructure of nanoparticles were examined by transmission electron microscopy, Nanoparticle Size Analyzer, and Fourier transform infrared spectroscopy. The release of tetracycline and lovastatin was quantified using a UV-Vis spectrophotometer. Furthermore, the cytotoxic effect and alkaline phosphatase activity of the nanoparticles in osteoblast cell cultures as well as antibacterial activity against periodontal pathogens were investigated. Finally, the bone regeneration potential of PLGA nanoparticles in three-walled defects in beagle dogs was investigated. The results indicated that PLGA-lovastatin-chitosan-tetracycline nanoparticles showed good biocompatibility, antibacterial activity, and increased alkaline phosphatase activity. The volumetric analysis from micro-CT revealed significantly increased new bone formation in defects filled with nanoparticles in dogs. This novel local delivery device might be useful as an adjunctive treatment in periodontal regenerative therapy. PMID:26848264

  1. Grafting of 4-aminomethylbenzensulfonamide-lipoic acid conjugate on gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Stiti, M.; Bouzit, H.; Abdaoui, M.; Winum, J. Y.

    2012-02-01

    In this paper, we describe the synthesis of goldnanoparticles bearing aminomethylbenzensulfonamide via a lipoyl moiety. The resulting stable nanoparticles with an average size of 4.0 nm have been achieved by a facile and high-yielding one phase method, by the action of 4-aminomethylbenzensulfonamide-lipoic acid bioconjugate on chloroauric acide, using dimethylsulfoxide (DMSO) as the solvent and sodium tetrahydridoborate (NaBH4) as the reducing agent. UV-vis absorption, transmission electron microscopy (TEM) and X-ray diffraction were used to analyse the morphology and the structure of the obtained nanoparticles. Preliminary study shows that these new nanoparticles are endowed with highly and specific inhibitory activity for the isoform (IX) of carbonic anhydrase over expressed in many cancers, and are therefore attractive candidate to be used both in diagnosis and in treatment of tumours.

  2. Effect of stearic acid-grafted starch compatibilizer on properties of linear low density polyethylene/thermoplastic starch blown film.

    PubMed

    Khanoonkon, Nattaporn; Yoksan, Rangrong; Ogale, Amod A

    2016-02-10

    The present work aims to investigate the effect of stearic acid-grafted starch (ST-SA) on the rheological, thermal, optical, dynamic mechanical thermal, and tensile properties of linear low density polyethylene/thermoplastic starch (LLDPE/TPS) blends, as well as on their water vapor and oxygen barrier properties. Blends consisting of LLDPE and TPS in a weight ratio of 60:40 and ST-SA at different concentrations, i.e. 1, 3 and 5%, were prepared using a twin-screw extruder. The obtained resins were subsequently converted into films via blown film extrusion. Incorporation of ST-SA resulted in a decreased degree of shear thinning, reduced ambient temperature elasticity, and improved tensile strength, secant modulus, extensibility, and UV absorption, as well as diminished water vapor and oxygen permeabilities of the LLDPE/TPS blend. These effects are attributed to the enhanced interfacial adhesion between LLDPE and TPS phases through the compatibilizing effect induced by ST-SA, and the good dispersion of the TPS phase in the LLDPE matrix. The results confirmed that ST-SA could potentially be used as a compatibilizer for the LLDPE/TPS blend system. PMID:26686117

  3. Poly(2-vinylnaphthalene-alt-maleic acid)-graft polystyrene as a photoactive polymer micelle and stabilizer for polystyrene latexes

    SciTech Connect

    Cao, T.; Yin, W.; Webber, S.E. )

    1994-12-05

    Polymerization of maleic anhydride and 2-vinylnaphthalene produces alternating polymers. Imidization of the polymer with amino-terminated polystyrene yields different loadings of an alternating polymer with polystyrene combs''. Upton rigorous hydrolysis one obtains poly(2-vinylnaphthalene-alt-maleic acid)-graft-polystyrene (P2VNMA-PS), which is a fluorescent polymer with unusual solution properties and with significant surface activity. P2VNMA-PS forms a small micelle structure in solution or can be used as a surfactant for an emulsion polymerization of polystyrene (no cosurfactant is required), producing monodisperse latex particles which are stable for pH > 3.9. Centrifugation shows that >90% of the P2VNMA-PS is associated with the latex particles. Fluorescence quenching studies of the naphthalene excimer with Tl[sup +] indicate that approximately 84% and 77% of the naphthalene groups remain exposed to the aqueous phase when this polymer is micellized or incorporated onto a latex particle, respectively. These data imply that the P2VNMA-PS polymer is permanently associated with the exterior of the latex particle, as one would expect given the amphiphilic nature of this polymer.

  4. Multinuclear nuclear magnetic resonance spectroscopic and high-performance liquid chromatographic characterization of silica, grafted with specifically deuterated 4-((propylamino)methyl)benzoic acid.

    PubMed

    Gangoda, Mahinda E; Wijekoon, Asanka; Gregory, Roger B; Khitrin, Anatoly K

    2016-08-01

    Specifically deuterated 4-((propylamino)methyl)benzoic acid-grafted silica (PAMBA-silica) was prepared by benzylation of propylamino-grafted silica (PA-silica) by either in situ reduction by sodium cyanoborodeuteride (NaCNBD3) of the Schiff base, formed by the reaction between PA-silica and 4-formylbenzoic acid, or by NaCNBD3 reduction of the isolated Schiff base. The PAMBA-silicas, which contain amine and carboxylic acid functionalities, were characterized by elemental analysis, (13)C, (29)Si, and (2)H solid state NMR, and HPLC. Solid state (13)C NMR revealed that PAMBA-silica prepared by the in situ method consists of di-benzylated, mono-benzylated, and unreacted amino-groups while PAMBA-silica prepared by the two-step synthesis consists of only mono-benzylated and unreacted amino-groups. (29)Si solid-state NMR spectra indicated that no significant loss of propylamine groups had occurred during benzylation. Nearly ideal uniaxial rigid-limit (2)H NMR spectra of grafted 4-PAMBA ligands indicates that they form a rigid structure, which provides effective electrostatic screening of inner positive charges when the ligands are in zwitterionic form. HPLC columns packed with PAMBA-silica and PA-silica were evaluated for ionic solutes at different pH of the mobile phase. Retention times increased for cations and decreased for anions at increasing pH. These trends show that PAMBA-silicas act as cation and anion exchangers at high and low pH, respectively. The pKa values of grafted carboxylic acid, determined from HPLC of weakly retaining solutes, are close to pKa of the solution PAMBA. PMID:27372413

  5. Development of (153) Sm-folate-polyethyleneimine-conjugated chitosan nanoparticles for targeted therapy.

    PubMed

    Mollarazi, Esmail; Jalilian, Amir R; Johari-Daha, Fariba; Atyabi, Fatemeh

    2015-06-30

    The aim of this study was to develop biocompatible, water-soluble (153) Sm-labeled chitosan nanoparticles (NPs) containing folate and polyethyleneimine functionalities i.e. chitosan-graft-PEI-folate (CHI-DTPA-g-PEI-FA), suitable for targeted therapy. The physicochemical properties of the obtained NPs were characterized by dynamic light-scattering analysis for their mean size, size distribution, and zeta potential; scanning electron microscopy for surface morphology; and (1) H-NMR, FT-IR analyses for molecular dispersity of folate in the NPs. NPs were spherical with mean diameter below 250 nm, polydispersity of below 0.15, and positive zeta potential values. The NP complex ((153) Sm-CHI-DTPA-g-PEI-FA) was stable at 25 °C (6-8 h, >90% radiochemical purity, instant thin layer chromatography (ITLC)). Binding studies using fluorescent NPs for internalization also demonstrated significant uptake in MCF-7 cells. MCF-7 cell internalization was significantly greater for 4T1. In blocking studies, both MCF-7 and 4T1 cell lines demonstrated specific folate receptor (FR) binding (decreasing 45%). In vivo biodistribution studies indicated major excretion of NPs metabolites and/or free (153) Sm through the kidneys. The preliminary imaging studies in 4T1 tumor-bearing mice showed minor uptake up to 96 h. The present folic acid that functionalized chitosan NP is a candidate material for folate receptor therapy. PMID:26036233

  6. Development of acid-resistant alginate/trimethyl chitosan nanoparticles containing cationic β-cyclodextrin polymers for insulin oral delivery.

    PubMed

    Mansourpour, Maryam; Mahjub, Reza; Amini, Mohsen; Ostad, Seyed Naser; Shamsa, Elnaz Sadat; Rafiee-Tehrani, Morteza; Dorkoosh, Farid Abedin

    2015-08-01

    In this study, the use of trimethylchitosan (TMC), by higher solubility in comparison with chitosan, in alginate/chitosan nanoparticles containing cationic β-cyclodextrin polymers (CPβCDs) has been studied, with the aim of increasing insulin uptake by nanoparticles. Firstly, TMCs were synthesized by iodomethane, and CPβCDs were synthesized within a one-step polycondensation reaction using choline chloride (CC) and epichlorohydrine (EP). Insulin-CβCDPs complex was prepared by mixing 1:1 portion of insulin and CPβCDs solutions. Then, nanoparticles prepared in a three-step procedure based on the iono-tropic pregelation method. Nanoparticles screened using experimental design and Placket Burman methodology to obtain minimum size and polydispercity index (pdI) and the highest entrapment efficiency (EE). CPβCDs and TMC solution concentration and pH and alginate and calcium chloride solution concentrations are found as the significant parameters on size, PdI, and EE. The nanoparticles with proper physicochemical properties were obtained; the size, PdI, and EE% of optimized nanoparticles were reported as 150.82 ± 21 nm, 0.362 ± 0.036, and 93.2% ± 4.1, respectively. The cumulative insulin release in intestinal condition achieved was 50.2% during 6 h. By SEM imaging, separate, spherical, and nonaggregated nanoparticles were found. In the cytotoxicity studies on Caco-2 cell culture, no significant cytotoxicity was observed in 5 h of incubation, but after 24 h of incubation, viability was decreased to 50% in 0.5 mμ of TMC concentration. Permeability studies across Caco-2 cells had been carried out, and permeability achieved in 240 min was 8.41 ± 0.39%, which shows noticeable increase in comparison with chitosan nanoparticles. Thus, according to the results, the optimized nanoparticles can be used as a new insulin oral delivery system. PMID:25604700

  7. Nitric Oxide-Releasing Chitosan Oligosaccharides as Antibacterial Agents

    PubMed Central

    Lu, Yuan; Slomberg, Danielle L.; Schoenfisch, Mark H.

    2014-01-01

    Secondary amine-functionalized chitosan oligosaccharides of different molecular weights (i.e., ~2500, 5000, 10000) were synthesized by grafting 2-methyl aziridine from the primary amines on chitosan oligosaccharides, followed by reaction with nitric oxide (NO) gas under basic conditions to yield N-diazeniumdiolate NO donors. The total NO storage, maximum NO flux, and half-life of the resulting NO-releasing chitosan oligosaccharides were controlled by the molar ratio of 2-methyl aziridine to primary amines (e.g., 1:1, 2:1) and the functional group surrounding the N-diazeniumdiolates (e.g., polyethylene glycol (PEG) chains), respectively. The secondary amine-modified chitosan oligosaccharides greatly increased the NO payload over existing biodegradable macromolecular NO donors. In addition, the water-solubility of the chitosan oligosaccharides enabled their penetration across the extracellular polysaccharides matrix of Pseudomonas aeruginosa biofilms and association with embedded bacteria. The effectiveness of these chitosan oligosaccharides at biofilm eradication was shown to depend on both the molecular weight and ionic characteristics. Low molecular weight and cationic chitosan oligosaccharides exhibited rapid association with bacteria throughout the entire biofilm, leading to enhanced biofilm killing. At concentrations resulting in 5-log killing of bacteria in Pseudomonas aeruginosa biofilms, the NO-releasing and control chitosan oligosaccharides elicited no significant cytotoxicity to mouse fibroblast L929 cells in vitro. PMID:24268196

  8. Hybrid chitosan-ß-glycerol phosphate-gelatin nano-/micro fibrous scaffolds with suitable mechanical and biological properties for tissue engineering.

    PubMed

    Lotfi, Marzieh; Bagherzadeh, Roohollah; Naderi-Meshkin, Hojjat; Mahdipour, Elahe; Mafinezhad, Asghar; Sadeghnia, Hamid Reza; Esmaily, Habibollah; Maleki, Masoud; Hasssanzadeh, Halimeh; Ghayaour-Mobarhan, Majid; Bidkhori, Hamid Reza; Bahrami, Ahmad Reza

    2016-03-01

    Scaffold-based tissue engineering is considered as a promising approach in the regenerative medicine. Graft instability of collagen, by causing poor mechanical properties and rapid degradation, and their hard handling remains major challenges to be addressed. In this research, a composite structured nano-/microfibrous scaffold, made from a mixture of chitosan-ß-glycerol phosphate-gelatin (chitosan-GP-gelatin) using a standard electrospinning set-up was developed. Gelatin-acid acetic and chitosan ß-glycerol phosphate-HCL solutions were prepared at ratios of 30/70, 50/50, 70/30 (w/w) and their mechanical and biological properties were engineered. Furthermore, the pore structure of the fabricated nanofibrous scaffolds was investigated and predicted using a theoretical model. Higher gelatin concentrations in the polymer blend resulted in significant increase in mean pore size and its distribution. Interaction between the scaffold and the contained cells was also monitored and compared in the test and control groups. Scaffolds with higher chitosan concentrations showed higher rate of cell attachment with better proliferation property, compared with gelatin-only scaffolds. The fabricated scaffolds, unlike many other natural polymers, also exhibit non-toxic and biodegradable properties in the grafted tissues. In conclusion, the data clearly showed that the fabricated biomaterial is a biologically compatible scaffold with potential to serve as a proper platform for retaining the cultured cells for further application in cell-based tissue engineering, especially in wound healing practices. These results suggested the potential of using mesoporous composite chitosan-GP-gelatin fibrous scaffolds for engineering three-dimensional tissues with different inherent cell characteristics. PMID:26566174

  9. Effect of CaCO₃/HCl pretreatment on the surface modification of chitin gel beads via graft copolymerization of 2-hydroxy ethyl methacrylate and 4-vinylpyridine.

    PubMed

    Yalinca, Zulal; Mohammed, Dana Ali Kader; Hadi, Jihad M; Yilmaz, Elvan

    2016-01-01

    Although chitin, poly(N-acetylglucosamine), possesses considerable potential as a biomaterial, it has not been as thoroughly studied as its derivative chitosan. In this study, the potential of chitin gel beads has been evaluated for surface modification via vinyl polymer grafting. Grafting behavior of two well-established vinyl monomers, namely 2-hydroxyethylmethacrylate (HEMA) and 4-vinylpyridine (4-VP) were investigated using cerium (IV) ammonium nitrate as the redox initiator with the aim of obtaining chemically functionalized more hydrophilic chitin surfaces. The intractable nature of chitin, which is one of its primary drawbacks as a grafting substrate was overcome by applying a CaCO3 treatment during bead preparation. The maximum grafting percentage of poly(HEMA) onto chitin bead without CaCO3 treatment was found to be 65%, while the value for CaCO3 treated chitin beads was 515%. The maximum grafting yield of poly(4-VP) on to CaCO3 treated chitin powder was 380% at optimum conditions. The grafting system was extensively characterized before and after grafting by FT-IR, SEM, C-13 NMR and XRD analyses. Significant improvement on the swelling capacities of chitin based gel beads in aqueous acidic, basic and neutral media was obtained. An account of the pros and cons of the system has been presented. PMID:26500177

  10. Composite vascular repair grafts via micro-imprinting and electrospinning

    NASA Astrophysics Data System (ADS)

    Liu, Yuanyuan; Xiang, Ke; Chen, Haiping; Li, Yu; Hu, Qingxi

    2015-04-01

    Composite vascular grafts formed by micro-imprinting and electrospinning exhibited improved mechanical properties relative to those formed by electrospinning alone. The three-layered composite grafts mimic the three-layered structure of natural blood vessels. The middle layer is made by micro-imprinting poly-p-dioxanone (PPDO), while the inner and outer layers are electrospun mixtures of chitosan and polyvinyl alcohol. The graft morphology is characterized with scanning electron microscopy. For constant graft thicknesses, the PPDO increases the mechanical strength. Cells cultivated on the vascular grafts adhere and proliferate better because of the natural, biological chitosan in the inner and outer layers. Overall, the composite scaffolds could be good candidates for blood vessel repair.

  11. Composite vascular repair grafts via micro-imprinting and electrospinning

    SciTech Connect

    Liu, Yuanyuan Hu, Qingxi; Xiang, Ke Chen, Haiping Li, Yu

    2015-04-15

    Composite vascular grafts formed by micro-imprinting and electrospinning exhibited improved mechanical properties relative to those formed by electrospinning alone. The three-layered composite grafts mimic the three-layered structure of natural blood vessels. The middle layer is made by micro-imprinting poly-p-dioxanone (PPDO), while the inner and outer layers are electrospun mixtures of chitosan and polyvinyl alcohol. The graft morphology is characterized with scanning electron microscopy. For constant graft thicknesses, the PPDO increases the mechanical strength. Cells cultivated on the vascular grafts adhere and proliferate better because of the natural, biological chitosan in the inner and outer layers. Overall, the composite scaffolds could be good candidates for blood vessel repair.

  12. Graft copolymerization of acrylic acid to cassava starch--evaluation of the influences of process parameters by an experimental design method.

    PubMed

    Witono, J R; Noordergraaf, I W; Heeres, H J; Janssen, L P B M

    2012-11-01

    The graft copolymerization of cassava starch with acrylic acid was investigated using a free radical initiator system (Fe(2+)/H(2)O(2) redox system) in water. A comprehensive understanding of the important variables and their interaction has been obtained by applying an experimental design method. In this approach, two ('high' and 'low') values of selected variables are considered. Important result parameters are add-on and the grafting efficiency. Out of eight reaction variables, it was found that only temperature, starch concentration and the starch to monomer ratio have a pronounced influence on these response parameters. Moderate reaction temperature (40 °C) and high starch concentration (10%) give relatively good results of add-on and grafting efficiency. A low starch to monomer ratio favors add-on but decreases grafting efficiency. These findings can be used to optimize the production of cassava starch-acrylate copolymers and to gain insight in the process-product property interactions, for various applications. PMID:22944411

  13. Extraction of chitosan from shrimp shells waste and application in antibacterial finishing of bamboo rayon.

    PubMed

    Teli, M D; Sheikh, Javed

    2012-06-01

    Chitosan can be best utilized as safe antibacterial agent for textiles but there is always a limitation of its durability. The chitin containing shellfish waste is available in huge quantities, but very low quantities are utilized for extraction of high value products like chitosan. In the current work chitosan was extracted from shrimp shells and then used as antibacterial exhaust finishing agent for grafted bamboo rayon. Chitosan bound bamboo rayon was then evaluated for antibacterial activity against both gram positive and gram negative bacteria. The product showed antibacterial activity against both types of bacterias which was durable till 30 washes. PMID:22522048

  14. Chitosan-g-lactide copolymers for fabrication of 3D scaffolds for tissue engineering

    NASA Astrophysics Data System (ADS)

    Demina, T. S.; Zaytseva-Zotova, D. S.; Timashev, P. S.; Bagratashvili, V. N.; Bardakova, K. N.; Sevrin, Ch; Svidchenko, E. A.; Surin, N. M.; Markvicheva, E. A.; Grandfils, Ch; Akopova, T. A.

    2015-07-01

    Chitosan-g-oligo (L, D-lactide) copolymers were synthesized and assessed to fabricate a number of 3D scaffolds using a variety of technologies such as oil/water emulsion evaporation technique, freeze-drying and two-photon photopolymerization. Solid-state copolymerization method allowed us to graft up to 160 wt-% of oligolactide onto chitosan backbone via chitosan amino group acetylation with substitution degree reaching up to 0.41. Grafting of hydrophobic oligolactide side chains with polymerization degree up to 10 results in chitosan amphiphilic properties. The synthesized chitosan-g-lactide copolymers were used to design 3D scaffolds for tissue engineering such as spherical microparticles and macroporous hydrogels.

  15. Effectiveness of silane monomer and gamma radiation on chitosan films and PCL-based composites

    NASA Astrophysics Data System (ADS)

    Sharmin, Nusrat; Khan, Ruhul A.; Dussault, Dominic; Salmieri, Stephane; Akter, Nousin; Lacroix, Monique

    2012-08-01

    Chitosan films were prepared by casting from its 1% (w/w) solution. Tensile strength (TS) and tensile modulus (TM) of chitosan films were found to be 30 MPa and 450 MPa, respectively. Silane monomer (3-aminopropyl tri-methoxysilane) (0.25%, w/w) was added into the chitosan solution (1%, w/w) and films were casted. Then films were exposed to gamma radiation (5-25 kGy) and mechanical properties were investigated. It was found that at 10 kGy, the values of TS and TM were improved significantly. Silane grafted chitosan film reinforced poly(caprolactone) (PCL)-based tri-layer composites were prepared by compression molding. Silane improved interfacial adhesion between chitosan and PCL in composites. Surface of the films was investigated by scanning electron microscope (SEM) and found better morphology for silane grafted films.

  16. Development of boronic acid grafted random copolymer sensing fluid for continuous glucose monitoring

    PubMed Central

    Li, Siqi; Davis, Erin N; Anderson, Jordan; Lin, Qiao; Wang, Qian

    2009-01-01

    We have previously presented a MEMS viscometric sensor for continuous glucose monitoring using protein Concanavalin A (Con A). To address its drawbacks including immunotoxicity and instability issues, we have synthesized stable, biocompatible copolymers poly(acrylamide-ran-3- acrylamidophenylboronic acid) (PAA-ran-PAAPBA) for viscosity based glucose sensing. We found that PAA-ran-PAAPBA showed very high binding specificity to glucose. Several key factors such as polymer compositions, polymer molecular weights and polymer concentrations have been investigated to optimize viscometric responses. This polymer is able to detect glucose under physiological conditions in a reversible manner. Therefore, it has the potential to enable the highly reliable, continuous monitoring of glucose in subcutaneous tissue using the MEMS device. PMID:19067585

  17. An environmentally benign dual action antimicrobial: quaternized chitosan/sodium alga acid multilayer films and silver nanoparticles decorated on magnetic nanoparticles.

    PubMed

    Jin, Feng; Xiang, Qian; Chen, Xiaoqin; Peng, Xuefeng; Xing, Xiaodong

    2016-10-01

    There is an urgent need to develop a puissant and environmentally benign antibacterial composite that act via multiple mechanisms to make response to the potentially daunting complexity of the microbial population and microbial antibiotic resistance. In this work, a facile and green approach, layer-by-layer self-assembly technology was applied to assemble polycation quaternized chitosan (QAC) and polyanion sodium alga acid onto magnetic nanoparticles (MNPs). Then silver nanoparticles (AgNPs) with stable and narrow-sized distribution in the range of 25-35 nm were immobilized on the surface of MNPs with L-ascorbic acid as reducing agent and organic multilayers as stabilizer. Through above modification on MNPs, we expected to achieve a green dual antibacterial and recyclable composite via the combined antibacterial action of QAC and AgNPs. Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, transmission electron microscopy, zeta potentials, and dynamic light scattering were employed to confirm the success of the surface functionalization. Silver ion release process was detected by inductively coupled plasma mass spectrometry. Furthermore, the antibacterial properties of the biomaterials against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus were studied. The modified MNPs exhibited rapid, efficient, and long-lasting biocidal abilities against E. coli and S. aureus. The magnetic antibacterial composite still showed excellent antibacterial efficiency during five exposure/collection/recycle procedures. PMID:27405094

  18. Carboxymethyl chitosan-folic acid-conjugated Fe3O4@SiO2 as a safe and targeting antitumor nanovehicle in vitro

    PubMed Central

    2014-01-01

    A synthetic method to prepare a core-shell-structured Fe3O4@SiO2 as a safe nanovehicle for tumor cell targeting has been developed. Superparamagnetic iron oxide is encapsulated inside nonporous silica as the core to provide magnetic targeting. Carboxymethyl chitosan-folic acid (OCMCS-FA) synthesized through coupling folic acid (FA) with OCMCS is then covalently linked to the silica shell and renders new and improved functions because of the original biocompatible properties of OCMCS and the targeting efficacy of FA. Cellular uptake of the nanovehicle was assayed by confocal laser scanning microscope using rhodamine B (RB) as a fluorescent marker in HeLa cells. The results show that the surface modification of the core-shell silica nanovehicle with OCMCS-FA enhances the internalization of nanovehicle to HeLa cells which over-express the folate receptor. The cell viability assay demonstrated that Fe3O4@SiO2-OCMCS-FA nanovehicle has low toxicity and can be used as an eligible candidate for drug delivery system. These unique advantages make the prepared core-shell nanovehicle promising for cancer-specific targeting and therapy. PMID:24667013

  19. Removal of antibiotics from water in the coexistence of suspended particles and natural organic matters using amino-acid-modified-chitosan flocculants: A combined experimental and theoretical study.

    PubMed

    Jia, Shuying; Yang, Zhen; Ren, Kexin; Tian, Ziqi; Dong, Chang; Ma, Ruixue; Yu, Ge; Yang, Weiben

    2016-11-01

    Contamination of trace antibiotics is widely found in surface water sources. This work delineates removal of trace antibiotics (norfloxacin (NOR), sulfadiazine (SDZ) or tylosin (TYL)) from synthetic surface water by flocculation, in the coexistence of inorganic suspended particles (kaolin) and natural organic matter (humic acid, HA). To avoid extra pollution caused by petrochemical products-based modification reagents, environmental-friendly amino-acid-modified-chitosan flocculants, Ctrp and Ctyr, with different functional aromatic-rings structures were employed. Jar tests at various pHs exhibited that, Ctyr, owning phenol groups as electron donors, was favored for elimination of cationic NOR (∼50% removal; optimal pH: 6; optimal dosage: 4mg/L) and TYL (∼60% removal; optimal pH: 7; optimal dosage: 7.5mg/L), due to π-π electron donator-acceptor (EDA) effect and unconventional H-bonds. Differently, Ctrp with indole groups as electron acceptor had better removal rate (∼50%) of SDZ anions (electron donator). According to correlation analysis, the coexisted kaolin and HA played positive roles in antibiotics' removal. Detailed pairwise interactions in molecular level among different components were clarified by spectral analysis and theoretical calculations (density functional theory), which are important for both the structural design of new flocculants aiming at targeted contaminants and understanding the environmental behaviors of antibiotics in water. PMID:27348257

  20. Complex coacervation of hyaluronic acid and chitosan: effects of pH, ionic strength, charge density, chain length and the charge ratio.

    PubMed

    Kayitmazer, A B; Koksal, A F; Kilic Iyilik, E

    2015-11-28

    Hyaluronic acid (HA) and chitosan (CH) can form nanoparticles, hydrogels, microspheres, sponges, and films, all with a wide range of biomedical applications. This variety of phases reflects the multiple pathways available to HA/CH complexes. Here, we use turbidimetry, dynamic light scattering, light microscopy and zeta potential measurements to show that the state of the dense phase depends on the molar ratio of HA carboxyl to CH amines, and is strongly dependent on their respective degrees of ionization, α and β. Due to the strong charge complementarity between HA and CH, electrostatic self-assembly takes place at very acidic pH, but is almost unobservable at ionic strength (I) ≥ 1.5 M NaCl. All systems display discontinuity in the I-dependence of the turbidity, corresponding to a transition from coacervates to flocculates. An increase in either polymer chain length or charge density enhances phase separation. Remarkably, non-stoichiometric coacervate suspensions form at zeta potentials far away from zero. This result is attributed to the entropic effects of chain semi-flexibility as well as to the charge mismatch between the two biopolymers. PMID:26406548

  1. Improved homopolymer separation to enable the application of 1H NMR and HPLC for the determination of the reaction parameters of the graft copolymerization of acrylic acid onto starch.

    PubMed

    Witono, Judy R; Marsman, Jan Henk; Noordergraaf, Inge-Willem; Heeres, Hero J; Janssen, Leon P B M

    2013-04-01

    Graft copolymers of starch with acrylic acid are a promising green, bio based material with many potential applications. The grafting of acrylic acid onto cassava starch in an aqueous medium initiated by Fenton's reagent has been studied. Common grafting result parameters are add-on (yield) and graft efficiency (selectivity). However, the analysis of the reaction products and an accurate determination of these parameters stand or fall with a complete separation of the entangled but ungrafted homopolymer from the grafted product. Therefore, this separation is the core of the newly developed analytical procedure. An appropriate solvent has been selected with dedicated testing from the range methanol, ethanol, acetone, dioxane, 2-propanol, and 1-propanol. Acetone showed the best performance in many respects. It has a high dissolving power for the homopolymer, as well as the highest yield of precipitation for the starch derivatives and it is the most economical in use. After the successful separation, the precipitated graft copolymers could be analyzed quantitatively by nuclear magnetic resonance. The liquid with homopolymer and unreacted monomer was analyzed by high pressure liquid chromatography. Proof of grafting has been found by FTIR and TGA analyses. The mass balance calculation shows a systematic error which appears fairly consistent: 18.0±2.5 wt%. This was used as a correction factor in the calculation of the grafting parameters but more importantly, it means that the method we developed has a high level of repeatability, in the order of 97%. PMID:23435285

  2. Preparation and characterization of hybrid pH-sensitive hydrogels of chitosan-co-acrylic acid for controlled release of verapamil.

    PubMed

    Ranjha, Nazar M; Ayub, Gohar; Naseem, Shahzad; Ansari, Muhammad Tayyab

    2010-10-01

    In the present work crosslinked hydrogels based on chitosan (CS) and acrylic acid (AA) were prepared by free radical polymerization with various feed compositions using N,N methylenebisacrylamide (MBA) as crosslinking agent. Benzoyl peroxide was used as catalyst. Fourier transform infrared spectra (FTIR) confirmed the formation of the crosslinked hydrogels. This hydrogel is formed due to electrostatic interaction between cationic groups in CS and anionic groups in AA. Prepared hydrogels were used for dynamic and equilibrium swelling studies. For swelling behavior, effect of pH, polymeric and monomeric compositions and degree of crosslinking were investigated. Swelling studies were performed in USP phosphate buffer solutions of varying pH 1.2, 5.5, 6.5 and 7.5. Results showed that swelling increased by increasing AA contents in structure of hydrogels in solutions of higher pH values. This is due to the presence of more carboxylic groups available for ionization. On the other hand by increasing the chitosan content swelling increased in a solution of acidic pH, but this swelling was not significant and it is due to ionization of amine groups present in the structure of hydrogel. Swelling decreased with increase in crosslinking ratio owing to tighter hydrogel structure. Porosity and sol-gel fraction were also measured. With increase in CS and AA contents porosity and gel fraction increased, whereas by increasing MBA content porosity decreased and gel fraction increased. Furthermore, diffusion coefficient (D) and the network parameters i.e., the average molecular weight between crosslinks (M(c)), polymer volume fraction in swollen state (V(2s)), number of repeating units between crosslinks (M(r)) and crosslinking density (q) were calculated using Flory-Rehner theory. Selected samples were loaded with a model drug verapamil. Release of verapamil depends on the ratios of CS/AA, degree of crosslinking and pH of the medium. The release mechanisms were studied by fitting

  3. Bone morphogenetic protein-2-encapsulated grafted-poly-lactic acid-polycaprolactone nanoparticles promote bone repair.

    PubMed

    Xu, Xiaojun; Yang, Jun; Ding, Lifeng; Li, Jianjun

    2015-01-01

    The aim of this study is to test the efficacy of a novel tissue-engineered bone in repairing bone defects, using poly-lactic-acid-polycaprolactone (PLA-PCL) scaffolding seeded with PEG-bone morphogenetic protein-2 (BMP-2)-transfected rBMSCs (rabbit bone marrow stromal cells). The rBMSCs were transfected with PEG/BMP-2 or liposome/BMP-2, and then implanted into a PLA-PCL tissue-engineered bone. The protein level of BMP-2 was assessed by Western blot analysis and immunohistochemistry. ELISA was used to measure the amount of BMP-2 secreted in the culture media. The mRNA level of BMP-2 and osteocalcin was assayed quantitatively by real-time PCR. The middle portion of the bilateral radius in New Zealand rabbits was excised and implanted with tissue-engineered bone, and the modified areas were monitored by X-ray, hematoxylin-eosin staining, and immunohistochemistry staining of BMP-2. PEG-BMP-2 nanoparticles (NPs) and BMP-2-loaded PEG-PLA-PCL tissue-engineered bones were successfully constructed. The novel PEG-PLA-PCL NPs/DNA complex was a superior option for transfecting BMP-2 in rBMSCs compared to normal liposomes Moreover, the mRNA level of osteocalcin and alkaline phosphatase activity was also elevated upon transfection of BMP-2-encapsulated NPs. In vivo implants with BMP-2-carried tissue-engineered bone exhibited dramatic augmentation of BMP-2 and effective bone formation in the rabbit ectopic model. The PEG-PLA-PCL NPs/BMP-2 complex had an advantageous effect on bone repair, which provided an important theoretic basis for potential clinical treatments. PMID:25158862

  4. Novel chitosan-spotted alginate fibers from wet-spinning of alginate solutions containing emulsified chitosan-citrate complex and their characterization.

    PubMed

    Watthanaphanit, Anyarat; Supaphol, Pitt; Furuike, Tetsuya; Tokura, Seiichi; Tamura, Hiroshi; Rujiravanit, Ratana

    2009-02-01

    The major problem associated with the production of alginate/chitosan hybridized fibers by wet spinning is the formation of gels due to ionic interactions of the oppositely charged molecules of alginate and chitosan when these two polymers are directly mixed. Here, we proposed a novel method of using chitosan in the form of an emulsion. The emulsion was prepared by adding a primary emulsion of olive oil in a sodium dodecyl sulfate (SDS) aqueous solution into a chitosan-citrate complex. The complexation of chitosan with citric acid is the key of this method. The citrate ions neutralize the positive charges of chitosan, rendering the chitosan-citrate complex to readily penetrate into the core of the SDS/olive oil micelles. The obtained emulsified chitosan-citrate complex (hereafter, the chitosan-citrate emulsion) of varying amount was then added into an alginate aqueous solution to prepare the alginate/chitosan spinning dope suspensions. The alginate/chitosan hybridized fibers showed spotty features of the emulsified chitosan-citrate complex particles locating close to the surface and the inside of the hybridized fibers. At the lowest content of incorporated chitosan (i.e., 0.5% w/w chitosan), both the tenacity and the elongation at break of the obtained chitosan-spotted alginate fibers were the greatest. Further increase in the chitosan content resulted in a monotonous decrease in the property values. Lastly, preliminary studies demonstrated that the obtained chitosan-spotted alginate fibers showed great promises as carriers for drug delivery. PMID:19072144

  5. Chemical modification of graphite surfaces using chitosan as a mediator

    SciTech Connect

    Hatley, M.E.; Albahadily, F.N.

    1995-12-01

    Several techniques for modifying graphite surfaces have been utilized the last two decades. Some of these techniques have a few limitations which include monolayer coverage and nonspecific binding to the graphite surfaces. In this report, we describe a novel approach to modify graphite surfaces using chitosan. The graphite is coated with an acidic chitosan solution. After drying, a chitosan film is formed on the graphite surfaces. Glutaraldehyde is attached to the chitosan through an amide linkage. The desired modifiers which contain amine groups are then attached to the free end of the glutaraldehyde. Utilization of the modified graphite surfaces in paste electrodes will be discussed.

  6. Design and development of multilayer vascular graft

    NASA Astrophysics Data System (ADS)

    Madhavan, Krishna

    2011-07-01

    Vascular graft is a widely-used medical device for the treatment of vascular diseases such as atherosclerosis and aneurysm as well as for the use of vascular access and pediatric shunt, which are major causes of mortality and morbidity in this world. Dysfunction of vascular grafts often occurs, particularly for grafts with diameter less than 6mm, and is associated with the design of graft materials. Mechanical strength, compliance, permeability, endothelialization and availability are issues of most concern for vascular graft materials. To address these issues, we have designed a biodegradable, compliant graft made of hybrid multilayer by combining an intimal equivalent, electrospun heparin-impregnated poly-epsilon-caprolactone nanofibers, with a medial equivalent, a crosslinked collagen-chitosan-based gel scaffold. The intimal equivalent is designed to build mechanical strength and stability suitable for in vivo grafting and to prevent thrombosis. The medial equivalent is designed to serve as a scaffold for the activity of the smooth muscle cells important for vascular healing and regeneration. Our results have shown that genipin is a biocompatible crosslinker to enhance the mechanical properties of collagen-chitosan based scaffolds, and the degradation time and the activity of smooth muscle cells in the scaffold can be modulated by the crosslinking degree. For vascular grafting and regeneration in vivo, an important design parameter of the hybrid multilayer is the interface adhesion between the intimal and medial equivalents. With diametrically opposite affinities to water, delamination of the two layers occurs. Physical or chemical modification techniques were thus used to enhance the adhesion. Microscopic examination and graft-relevant functional characterizations have been performed to evaluate these techniques. Results from characterization of microstructure and functional properties, including burst strength, compliance, water permeability and suture

  7. Synthesis and characterization of chitosan-g-N-methyl piperazinium chloride: A hybrid flocculant.

    PubMed

    Dharani, Muthumanickam; Balasubramanian, Sengottuvelan

    2015-11-01

    Flocculation is one of the most widely applied techniques for water treatment. Flocculants based on natural polymer has received more attention due to their eco-friendliness in recent years. New water soluble N-methyl piperazinium chloride grafted chitosan flocculant (chitosan-g-N-MPC) was successfully synthesized and thoroughly characterized using FTIR, NMR and powder X-ray diffraction analytical techniques. Incorporation of N-MPC enhanced the ionic character of the chitosan backbone and improved its water solubility. The flocculation performance of chitosan-g-N-MPC was tested against bentonite suspension. The flocculation performance of chitosan-g-N-MPC was investigated under various pH conditions. Turbidity and zeta potential measurements were employed to investigate the flocculation behavior of the chitosan-g-N-MPC. The characteristics of the industrial wastewater before and after flocculation were analyzed. The morphology of the polymer and flocs were studied by TEM analysis. PMID:26366532

  8. Antimicrobial and physicochemical properties of chitosan-HPMC-based films.

    PubMed

    Möller, Heike; Grelier, Stéphane; Pardon, Patrick; Coma, Véronique

    2004-10-20

    To prepare composite films from biopolymers with anti-listerial activity and moisture barrier properties, the antimicrobial efficiency of chitosan-hydroxy propyl methyl cellulose (HPMC) films, chitosan-HPMC films associated with lipid, and chitosan-HPMC films chemically modified by cross-linking were evaluated. In addition, the physicochemical properties of composite films were evaluated to determine their potential for food applications. The incorporation of stearic acid into the composite chitosan-HPMC film formulation decreased water sensitivity such as initial solubility in water and water drop angle. Thus, cross-linking of composite chitosan-HPMC, using citric acid as the cross-linking agent, led to a 40% reduction in solubility in water. The water vapor transfer rate of HPMC film, approximately 270 g x m(-2) x day(-1) x atm(-1), was improved by incorporating chitosan and was further reduced 40% by the addition of stearic acid and/or cross-linking. Anti-listerial activity of films was determined on solid medium by a numeration technique. Chitosan-HPMC-based films, with and without stearic acid, inhibited the growth of Listeria monocytogenes completely. On the other hand, a loss of antimicrobial activity after chemical cross-linking modification was observed. FTIR and 13C NMR analyses were then conducted in order to study a potential chemical modification of biopolymers such as a chemical reaction with the amino group of chitosan. To complete the study, the mechanical properties of composite films were determined from tensile strength assays. PMID:15479027

  9. Hierarchical structure and physicochemical properties of plasticized chitosan.

    PubMed

    Meng, Qingkai; Heuzey, Marie-Claude; Carreau, Pierre J

    2014-04-14

    Plasticized chitosan with hierarchical structure, including multiple length scale structural units, was prepared by a "melt"-based method, that is, thermomechanical mixing, as opposed to the usual casting-evaporation procedure. Chitosan was successfully plasticized by thermomechanical mixing in the presence of concentrated lactic acid and glycerol using a batch mixer. Different plasticization formulations were compared in this study, in which concentrated lactic acid was used as protonation agent as well as plasticizer. The microstructure of thermomechanically plasticized chitosan was investigated by X-ray diffraction, scanning electron microscopy, and optical microscopy. With increasing amount of additional plasticizers (glycerol or water), the crystallinity of the plasticized chitosan decreased from 63.7% for the original chitosan powder to almost zero for the sample plasticized with additional water. Salt linkage between lactic acid molecules and amino side chains of chitosan was confirmed by FTIR spectroscopy: the lactic acid molecules expanded the space between the chitosan molecules of the crystalline phase. In the presence of other plasticizers (glycerol and water), various levels of structural units including an amorphous phase, nanofibrils, nanofibril clusters, and microfibers were produced under mechanical shear and thermal energy and identified for the first time. The thermal and thermomechanical properties of the plasticized chitosan were measured by thermogravimetric analysis, differential scanning calorimetric, and DMA. These properties were correlated with the different levels of microstructure, including multiple structural units. PMID:24564751

  10. Sulfonic Acid- and Lithium Sulfonate-Grafted Poly(Vinylidene Fluoride) Electrospun Mats As Ionic Liquid Host for Electrochromic Device and Lithium-Ion Battery.

    PubMed

    Zhou, Rui; Liu, Wanshuang; Leong, Yew Wei; Xu, Jianwei; Lu, Xuehong

    2015-08-01

    Electrospun polymer nanofibrous mats loaded with ionic liquids (ILs) are promising nonvolatile electrolytes with high ionic conductivity. The large cations of ILs are, however, difficult to diffuse into solid electrodes, making them unappealing for application in some electrochemical devices. To address this issue, a new strategy is used to introduce proton conduction into an IL-based electrolyte. Poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) copolymer is functionalized with sulfonic acid through covalent attachment of taurine. The sulfonic acid-grafted P(VDF-HFP) electrospun mats consist of interconnected nanofibers, leading to remarkable improvement in dimensional stability of the mats. IL-based polymer electrolytes are prepared by immersing the modified mats in 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM(+)BF4(-)). It is found that the SO3(-) groups can have Lewis acid-base interactions with the cations (BMIM(+)) of IL to promote the dissociation of ILs, and provide additional proton conduction, resulting in significantly improved ionic conductivity. Using this novel electrolyte, polyaniline-based electrochromic devices show higher transmittance contrast and faster switching behavior. Furthermore, the sulfonic acid-grafted P(VDF-HFP) electrospun mats can also be lithiated, giving additional lithium ion conduction for the IL-based electrolyte, with which Li/LiCoO2 batteries display enhanced C-rate performance. PMID:26167794

  11. Immunoadjuvant properties of chitosan.

    PubMed

    Marcinkiewicz, J; Polewska, A; Knapczyk, J

    1991-01-01

    Adjuvant activity of water insoluble chitosan suspension was examined in CBA mice. Among different types of immune reaction only T-dependent humoral response against SRBC was enhanced by injection of chitosan. The optimal conditions of administration of both agents (antigen-SRBC, adjuvant-chitosan) was established. PMID:1804042

  12. Application of chitin and chitosan derivatives in the pharmaceutical field.

    PubMed

    Kato, Yoshinori; Onishi, Hiraku; Machida, Yoshiharu

    2003-10-01

    Chitin and chitosan derivatives are used as excipients and drug carriers in the pharmaceutical field. Their derivatization contributed to expansion of application and decrease toxicity. Chitosan is used as an excipient in oral dosage form. Chitosan tablet can exhibit a sustained drug release compared to commercial products. Films prepared using chitin or chitosan have been developed as wound dressings, oral mucoadhesive and water-resisting adhesive by virtue of their release characteristics and adhesion. Intratumoral administration of gadopentetic acid-chitosan complex nanoparticles (approximately 430 nm in diameter) has been more effective for gadolinium neutron-capture therapy compared with a group treated with the solution. Compared to intragastrical feeding with diphtheria toxoid (DT) in PBS, a strong enhancement of the systemic (IgG) and local (IgA) immune responses against DT has been observed in mice fed with DT loaded chitosan microparticles (approximately 4.7 microm in size). When DNA-loaded chitosan microspheres (1.15 - 1.28 microm) were intramuscularly administrated into mice, high beta-galactosidase and luciferase productions were obtained even after a long post-transfection period (12 weeks). N-Succinyl-chitosan (Suc-Chi) has been studied for cancer chemotherapy as a drug carrier and the conjugates of mitomycin C with Suc-Chi exhibited good antitumor activities against various tumors. Furthermore, trimethyl-chitosan and monocarboxymethyl-chitosan has been shown to be effective as intestinal absorption enhancers due to their physiological properties. Chitosan-thioglycolic acid conjugates has been found to be a promising candidate as scaffold material in tissue engineering due to their physicochemical properties. This review summarizes the application of chitin and chitosan derivatives for hospital preparations and drug carriers. PMID:14529420

  13. Enhanced Neuroprotection of Acetyl-11-Keto-β-Boswellic Acid (AKBA)-Loaded O-Carboxymethyl Chitosan Nanoparticles Through Antioxidant and Anti-Inflammatory Pathways.

    PubMed

    Ding, Yi; Qiao, Youbei; Wang, Min; Zhang, Huinan; Li, Liang; Zhang, Yikai; Ge, Jie; Song, Ying; Li, Yuwen; Wen, Aidong

    2016-08-01

    Acetyl-11-keto-β-boswellic acid (AKBA), a main active constituent from Boswellia serrata resin, is a novel candidate for therapy of cerebral ischemia-reperfusion (I/R) injury. Nevertheless, its poor solubility in aqueous solvent, bioavailability, and rapid clearance limit its curative efficacy. To enhance its potency, in our study, AKBA-loaded o-carboxymethyl chitosan nanoparticle (AKBA-NP) delivery system was synthesized. The transmission electron microscopy and transmission electron microscope images of AKBA-NPs suggested that particle size was 132 ± 18 nm, and particles were spherical in shape with smooth morphology. In pharmacokinetics study, AKBA-NPs apparently increases the area under the curve of plasma concentration-time and prolonged half-life compared with AKBA. The tissue distribution study confirmed that AKBA-NPs had a better brain delivery efficacy in comparison with AKBA. The results from our pharmacodynamic studies showed that AKBA-NPs possess better neuroprotection compared with AKBA in primary neurons with oxygen-glucose deprivation (OGD) model and in animals with middle cerebral artery occlusion (MCAO) model. Additionally, AKBA-NPs modulate antioxidant and anti-inflammatory pathways more effectively than AKBA by increasing nuclear erythroid 2-related factor 2 and heme oxygenase-1 expression, and by decreasing nuclear factor-kappa B and 5-lipoxygenase expression. Collectively, our results suggest that AKBA-NPs serve as a potent delivery vehicle for AKBA in cerebral ischemic therapy. PMID:26162321

  14. The role of hyaluronic acid inclusion on the energetics of encapsulation and release of a protein molecule from chitosan-based nanoparticles.

    PubMed

    Al-Qadi, Sonia; Alatorre-Meda, Manuel; Martin-Pastor, Manuel; Taboada, Pablo; Remuñán-López, Carmen

    2016-05-01

    The synergistic effects of the polysaccharides chitosan (CS) and hyaluronic acid (HA) formulated into hybrid nanoparticles are promising for drug delivery. In the present work, we performed a detailed analysis of the molecular interactions involved in the TPP-assisted ionotropic gelation of CS hybrid nanoparticles with the objective of investigating the impact of HA inclusion on the particle formulation and on the in vitro release of insulin (INS) as a protein cargo. To do that, an in-depth thermodynamic study was carried out by isothermal titration calorimetry (ITC), nuclear magnetic resonance (NMR) and differential scanning calorimetry (DSC) techniques. Such analysis allowed us to elucidate the type and extent of interactions established by INS within the hybrid nanoparticles and to get further knowledge on the nature of its release mechanism in vitro. Overall, INS release from the CS nanoparticles was thermodynamically driven, and when including HA a weaker INS binding to the nanoparticles, hence, a faster release rate in vitro were observed. As a negative polyelectrolyte, HA might have sterically blocked the activated sites of CS, such as the amino groups, through chain entanglement, thereby, attenuating the competitive binding interactions of INS. As a consequence, INS might have experienced a spatial exclusion onto the surface of the hybrid nanoparticles to a greater extent which, in turn, would explain its initial abrupt release. PMID:26854581

  15. Novel biomimetic tripolymer scaffolds consisting of chitosan, collagen type 1, and hyaluronic acid for bone marrow-derived human mesenchymal stem cells-based bone tissue engineering.

    PubMed

    Mathews, Smitha; Bhonde, Ramesh; Gupta, Pawan Kumar; Totey, Satish

    2014-11-01

    Human bone marrow-derived mesenchymal stem cells (hMSCs) are an ideal osteogenic cell source for bone tissue engineering (BTE). A scaffold, in the context of BTE, is the extracellular matrix (ECM) that provides the unique microenvironment and play significant role in regulating cell behavior, differentiation, and development in an in vitro culture system. In this study, we have developed novel biomimetic tripolymer scaffolds for BTE using an ECM protein, collagen type 1; an ECM glycosaminoglycan, hyaluronic acid; and a natural osteoconductive polymer, chitosan. The scaffolds were characterized by scanning electron microscopy (SEM) and swelling ratio. The scaffolds were seeded with hMSCs and tested for cytocompatibility and osteogenic potential. The scaffolds supported cell adhesion, enhanced cell proliferation, promoted cell migration, showed good cell viability, and osteogenic potential. The cells were able to migrate out from the scaffolds in favorable conditions. SEM, alkaline phosphatase assay, and immunofluorescent staining confirmed the differentiation of hMSCs to osteogenic lineage in the scaffolds. In conclusion, we have successfully developed biomimetic scaffolds that supported the proliferation and differentiation of hMSCs. These scaffolds hold great promise as a cell-delivery vehicle for regenerative therapies and as a support system for enhancing bone regeneration. PMID:24723571

  16. Poly(lactic-co-glycolic) Acid/Nanohydroxyapatite Scaffold Containing Chitosan Microspheres with Adrenomedullin Delivery for Modulation Activity of Osteoblasts and Vascular Endothelial Cells

    PubMed Central

    Li, Chunyan; Chen, Yingxin; Dong, Shujun; Chen, Xuesi; Zhou, Yanmin

    2013-01-01

    Adrenomedullin (ADM) is a bioactive regulatory peptide that affects migration and proliferation of diverse cell types, including endothelial cells, smooth muscle cells, and osteoblast-like cells. This study investigated the effects of sustained release of ADM on the modulation activity of osteoblasts and vascular endothelial cells in vitro. Chitosan microspheres (CMs) were developed for ADM delivery. Poly(lactic-co-glycolic) acid and nano-hydroxyapatite were used to prepare scaffolds containing microspheres with ADM. The CMs showed rough surface morphology and high porosity, and they were well-distributed. The scaffolds exhibited relatively uniform pore sizes with interconnected pores. The addition of CMs improved the mechanical properties of the scaffolds without affecting their high porosity. In vitro degradation tests indicated that the addition of CMs increased the water absorption of the scaffolds and inhibited pH decline of phosphate-buffered saline medium. The expression levels of osteogenic-related and angiogenic-related genes were determined in MG63 cells and in human umbilical vein endothelial cells cultured on the scaffolds, respectively. The expression levels of osteogenic-related and angiogenic-related proteins were also detected by western blot analysis. Their expression levels in cells were improved on the ADM delivery scaffolds at a certain time point. The in vitro evaluation suggests that the microsphere-scaffold system is suitable as a model for bone tissue engineering. PMID:23841075

  17. Urocanic acid-modified chitosan nanoparticles can confer anti-inflammatory effect by delivering CD98 siRNA to macrophages.

    PubMed

    Xiao, Bo; Ma, Panpan; Viennois, Emilie; Merlin, Didier

    2016-07-01

    CD98 plays an important role in the development and progression of inflammation. Here, CD98 siRNA (siCD98) was complexed with urocanic acid-modified chitosan (UAC) to form nanoparticles (NPs), which were transfected into Raw 264.7 macrophages in an effort to convey anti-inflammatory effects. Characterization showed that the generated NPs had a desirable particle size (156.0-247.1nm), a slightly positive zeta potential (15.8-17.5mV), and no apparent cytotoxicity against Raw 264.7 macrophages and colon-26 cells compared to control NPs fabricated by Oligofectamine (OF) and siRNA. Cellular uptake experiments demonstrated that macrophages exhibited a time-dependent accumulation profile of UAC/siRNA NPs. Further in vitro gene silencing experiments revealed that UAC/siCD98 NPs with a weight ratio of 60:1 yielded the most efficient knockdowns of CD98 and the pro-inflammatory cytokine, TNF-α. Indeed, the RNAi efficiency obtained with our NPs was even higher than that of the positive control OF/siCD98 NPs. These results suggest that UAC/siCD98 NPs might be a safe, efficient and promising candidate for the treatment of inflammatory disease. PMID:27011348

  18. Hematopoietic stem cell capture and directional differentiation into vascular endothelial cells for metal stent-coated chitosan/hyaluronic acid loading CD133 antibody.

    PubMed

    Zhang, Shixuan; Zhang, Fan; Feng, Bo; Fan, Qingyu; Yang, Feng; Shang, Debin; Sui, Jinghan; Zhao, Hong

    2015-03-01

    A series of metal stents coated with chitosan/hyaluronic acid (CS/HA) loading antibodies by electrostatic self-assembled method were prepared, and the types of cells captured by antibodies and their differentiation in vascular endothelial cells (ECs) evaluated by molecular biology and scanning electron microscope. The results showed that CD133 stent can selectively capture hematopoietic stem cells (HSC),which directionally differentiate into vascular ECs in peripheral blood by (CS/HA) induction, and simultaneously inhibit migration and proliferation of immune cells and vascular smooth muscle cells (MCs). CD34 stent can capture HSC, hematopoietic progenitor cells that differentiate into vascular ECs and immune cells, promoting smooth MCs growth, leading to thrombosis, inflammation, and rejection. CD133 stent can be implanted into miniature pig heart coronary and can repair vascular damage by capturing own HSC, thus contributing to the rapid natural vascular repair, avoiding inflammation and rejection, thrombosis and restenosis. These studies demonstrated that CD133 stent of HSC capture will be an ideal coated metal stent providing a new therapeutic approach for cardiovascular and cerebrovascular disease. PMID:25404533

  19. Encapsulation of paclitaxel into lauric acid-O-carboxymethyl chitosan-transferrin micelles for hydrophobic drug delivery and site-specific targeted delivery.

    PubMed

    Nam, Joung-Pyo; Park, Seong-Cheol; Kim, Tae-Hun; Jang, Jae-Yeang; Choi, Changyong; Jang, Mi-Kyeong; Nah, Jae-Woon

    2013-11-30

    Transferrin/PEG/O-carboxymethyl chitosan/fatty acid/paclitaxel (TPOCFP) micelles were tested for suitability as a drug carrier characterized by low cytotoxicity, sustained release, high cellular uptake, and site-specific targeted delivery of hydrophobic drugs. Characterization, drug content, encapsulation efficiency, and in vitro drug release were investigated. When the feeding amount of paclitaxel (PTX) was increased, the drug content increased, but loading efficiency decreased. TPOCFP micelles had a spherical shape, with a particle size of approximately 140-649 nm. In vitro cell cytotoxicity and hemolysis assays were conducted to confirm the safety of the micelles. Anticancer activity and confocal laser scanning microscopy (CLSM) were used to confirm the targeting efficiency of target ligand-modified TPOCFP micelles. Anticancer activity and CLSM results clearly demonstrated that transferrin-modified TPOCFP micelles were quickly taken up by the cell. The endocytic pathway of TPOCFP micelles was analyzed by flow cytometry, revealing transfection via receptor-mediated endocytosis. These results suggest that PTX-encapsulated TPOCFP micelles may be used as an effective cancer-targeting drug delivery system for chemotherapy. PMID:24076228

  20. Metal ions doped chitosan-poly(acrylic acid) nanospheres: Synthesis and their application in simultaneously electrochemical detection of four markers of pancreatic cancer.

    PubMed

    Rong, Qinfeng; Feng, Feng; Ma, Zhanfang

    2016-01-15

    In this work, a one-pot method was designed to synthesize copper ions, cadmium ions, lead ions and zinc ions doped chitosan-poly(acrylic acid) nanospheres. Those nanospheres can not only produce independent electrochemical signals, but also react with glutaraldehyde (GA) to immobilize different labeled antibodies. Using the modified nanospheres as immunoprobes, a sandwich-type immunosensor was fabricated to simultaneous detection of four tumor markers (CEA, CA199, CA125 and CA242) of pancreatic cancer. This designed immunosensor exhibited good linear relationships in range from 0.1 to 100ng mL(-1) for CEA, 1 to 150UmL(-1) for CA199, CA125 and CA242, corresponding detection limits 0.02ng mL(-1), 0.4UmL(-1), 0.3UmL(-1) and 0.4UmL(-1), respectively. Meanwhile, the immunosensor was applied in analysis of clinical serum samples, whose results were well agreed with the enzyme-linked immunosorbent assay (ELISA), indicating that the proposed immunosensor gave a hope for the identification and validation of specific early cancer. PMID:26318783