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1

Structure and properties of gadolinium loaded calcium phosphate glasses  

NASA Astrophysics Data System (ADS)

The glass samples with composition xGd2O3-(50 - x)CaO-50P2O5 (0 ? x ? 9 mol%) were prepared by the conventional melt quench method. The structure and properties of gadolinium loaded in calcium phosphate glasses were investigated using XRD, SEM, DTA, IR and Raman spectroscopy. The XRD and SEM analysis for the samples show that the majority of samples are amorphous, and crystallization occurs when the content of Gd2O3 containing is up to 6 mol%. Two main crystalline phases, Ca2P2O7 and Gd3(P2O7)3, are embedded in an amorphous matrix. IR and Raman data indicate that glass structure consists of predominantly metaphosphate (Q2) units and the depolymerization of phosphate network with the addition of Gd2O3. Both the chemical durability and the glass transition temperature (Tg) are improved with the increase of Gd2O3, which suggests that the Gd acts a role of strengthening the cross-links between the phosphate chains of the glass.

Wang, Cuiling; Liang, Xiaofeng; Li, Haijian; Yu, Huijun; Li, Zhen; Yang, Shiyuan

2014-10-01

2

Production of a gadolinium-loaded liquid scintillator for the Daya Bay reactor neutrino experiment  

NASA Astrophysics Data System (ADS)

We report on the production and characterization of liquid scintillators for the detection of electron antineutrinos by the Daya Bay reactor neutrino experiment. A 185 tons of gadolinium-loaded (0.1% by mass) liquid scintillator (Gd-LS) and a 200 tons of unloaded liquid scintillator (LS) were successfully produced from a linear-alkylbenzene (LAB) solvent in 6 months. The scintillator properties, the production and purification systems, and the quality assurance and control (QA/QC) procedures are described.

Beriguete, Wanda; Cao, Jun; Ding, Yayun; Hans, Sunej; Heeger, Karsten M.; Hu, Liangming; Huang, Aizhong; Luk, Kam-Biu; Nemchenok, Igor; Qi, Ming; Rosero, Richard; Sun, Hansheng; Wang, Ruiguang; Wang, Yifang; Wen, Liangjian; Yang, Yi; Yeh, Minfang; Zhang, Zhiyong; Zhou, Li

2014-11-01

3

Targeting silymarin for improved hepatoprotective activity through chitosan nanoparticles  

PubMed Central

Introduction: Silymarin is one of the best known hepatoprotective drugs, which is obtained from the seeds of Silybum marianum L., Family: Asteraceae or Compositae. The plant has traditionally been used for centuries as a natural remedy for liver and biliary tract diseases. The aim of the present investigation was to enhance the hepatoprotective activity of silymarin by incorporating it in chitosan (Ch) nanoparticles (NPs) for passive targeted delivery, thereby prolonging its retention time. Materials and Methods: Silymarin loaded NPs were prepared by ionic gelation technique, which were then optimized using a central composite design in order to minimize the particle size and maximize the drug entrapment efficiency. The optimized formulation was evaluated for in vitro drug release study and in vitro study on Swiss Albino mice using carbon tetrachloride (CCL4) induced hepatotoxicity model. Results: In vitro dissolution studies illustrated sustained, zero order drug release from optimized formulation; also its therapeutic potential was amplified during in vitro studies on Swiss Albino mice using CCL4 induced hepatotoxicity model. Conclusion: The results suggested that NPs of silymarin could successfully enhance its hepatoprotective effect by passive targeting and sustained release.

Gupta, Swati; Singh, Shailendra Kumar; Girotra, Priti

2014-01-01

4

Production of Gadolinium-loaded Liquid Scintillator for the Daya Bay Reactor Neutrino Experiment  

E-print Network

We report on the production and characterization of liquid scintillators for the detection of electron antineutrinos by the Daya Bay Reactor Neutrino Experiment. One hundred eighty-five tons of gadolinium-loaded (0.1% by mass) liquid scintillator (Gd-LS) and two hundred tons of unloaded liquid scintillator (LS) were successfully produced from a linear-alkylbenzene (LAB) solvent in six months. The scintillator properties, the production and purification systems, and the quality assurance and control (QA/QC) procedures are described.

Wanda Beriguete; Jun Cao; Yayun Ding; Sunej Hans; Karsten M. Heeger; Liangming Hu; Aizhong Huang; Kam-Biu Luk; Igor Nemchenok; Ming Qi; Richard Rosero; Hansheng Sun; Ruiguang Wang; Yifang Wang; Liangjian Wen; Yi Yang; Minfang Yeh; Zhiyong Zhang; Li Zhou

2014-02-27

5

A new gadolinium-loaded liquid scintillator for reactor neutrino detection  

NASA Astrophysics Data System (ADS)

A high flash point, low toxicity gadolinium-loaded liquid scintillator (Gd-LS) has been developed for the detection of reactor neutrino. Carboxylic acid 3,5,5-trimethylhexanoic acid is used as complexing ligand to form organo-complex with gadolinium chloride, and 2,5-diphenyloxazole (PPO), and 1,4-bis[2-methylstyryl]benzene (bis-MSB) are used as primary fluor and wavelength shifter, respectively. The scintillator base is linear alkyl benzene (LAB). The Gd-LS prepared with such recipe has long attenuation length, high light yield and long-term stability. Eight hundred liters of Gd-LS (1 g/L Gd) was synthesized and tested in a prototype detector at Institute of High Energy Physics. Preliminary results of the obviously peaks corresponding to neutron captured by H and Gd give an additional evidence that such Gd-LS are very promising for anti-neutrino detection.

Ding, Yayun; Zhang, Zhiyong; Liu, Jinchang; Wang, Zhimin; Zhou, Pengju; Zhao, Yuliang

2008-01-01

6

Folate-targeted liposome encapsulating chitosan/oligonucleotide polyplexes for tumor targeting.  

PubMed

We previously reported that a liposome encapsulating polyethylenimine/oligonucleotides is suitable for in vivo delivery of nucleic acid therapeutics. However, toxicity of polyethylenimine is an obstacle in clinical application. To develop a liposome encapsulating polyplexes applicable to clinical use, we proposed to replace polyethylenimine with chitosan and thus constructed the liposome encapsulating low-molecular weight chitosan (LMWC)/oligonucleotide (ODN) polyplexes [LS(CO)]. ODN was completely complexed to LMWC at pH 5.5 and an N/P ratio 10 with a positive zeta potential of 19.81?±?1.11. The positively charged polyplexes were encapsulated into anionic liposome by membrane extrusion. Folate-targeted liposome encapsulating LMWC/ODN complex [FLS(CO)] was prepared by adding folate-conjugated phospholipid. The resulting LS(CO) and FLS(CO) were characterized with respect to size distribution, zeta potential, and colloidal stability. The LS(CO) and FLS(CO) were also evaluated for in vitro cellular uptake and cytotoxicity. The LS(CO) and FLS(CO) showed a narrow size distribution with a mean diameter of about 130 nm and neutral zeta potentials and remained stable for 7 days in 0.15-M NaCl at room temperature. FLS(CO) showed higher cellular uptake than LS(CO) in B16F10 murine melanoma cells. Furthermore, LS(CO) showed less toxicity as compared to liposome encapsulating polyethylenimine/oligonucleotides, representing a biocompatible nanocarrier of oligonucleotide therapeutics. PMID:24848761

Kang, Ji Hee; Battogtokh, Gantumur; Ko, Young Tag

2014-10-01

7

Novel norcantharidin-loaded liver targeting chitosan nanoparticles to enhance intestinal absorption.  

PubMed

In this paper, two novel liver-targeting nanoparticles, norcantharidin-loaded chitosan nanoparticles (NCTD-CS-NPs) and norcantharidin-associated galactosylated chitosan nanoparticles (NCTD-GC-NPs), were prepared using ionic cross-linkage. The physical properties, particle size, encapsulation efficiency, and drug release characteristics of the nanoparticles were investigated in vitro. To investigate the intestinal absorption mechanisms of the two preparations, a series of experiments was carried out, including in situ circulation method, in vitro everted gut sacs, and Ussing chamber perfusion technique. The absorption rate constants (Ka) of NCTD at different segments were found to be duodenum > jejunum > ileum > colon. The concentration had no distinctive effect on absorption kinetics, suggesting that drug absorption is not dose-dependent. The transport of NCTD was found to be inhibited by P-glycoprotein (P-gp) inhibitor, indicating that NCTD might be the substrate of P-gp. The order of the absorption enhancer effects were as follows: low molecular weight chitosan (CS-8kDa) > high molecular weight chitosan (CS-30kDa) > Poloxamer > sodium dodecyl sulfate (SDS) > sodium deoxycholate (SDCh). The results indicate that the chitosan nanoparticles can improve intestinal absorption of NCTD. PMID:22619530

Bei, Yong-yan; Chen, Xiao-yan; Liu, Yang; Xu, Jing-yu; Wang, Wen-juan; Gu, Zong-lin; Xing, Kong-lang; Zhu, Ai-jun; Chen, Wei-liang; Shi, Lin-seng; Wang, Qin; Zhang, Xue-nong; Zhang, Qiang

2012-01-01

8

Novel norcantharidin-loaded liver targeting chitosan nanoparticles to enhance intestinal absorption  

PubMed Central

In this paper, two novel liver-targeting nanoparticles, norcantharidin-loaded chitosan nanoparticles (NCTD-CS-NPs) and norcantharidin-associated galactosylated chitosan nanoparticles (NCTD-GC-NPs), were prepared using ionic cross-linkage. The physical properties, particle size, encapsulation efficiency, and drug release characteristics of the nanoparticles were investigated in vitro. To investigate the intestinal absorption mechanisms of the two preparations, a series of experiments was carried out, including in situ circulation method, in vitro everted gut sacs, and Ussing chamber perfusion technique. The absorption rate constants (Ka) of NCTD at different segments were found to be duodenum > jejunum > ileum > colon. The concentration had no distinctive effect on absorption kinetics, suggesting that drug absorption is not dose-dependent. The transport of NCTD was found to be inhibited by P-glycoprotein (P-gp) inhibitor, indicating that NCTD might be the substrate of P-gp. The order of the absorption enhancer effects were as follows: low molecular weight chitosan (CS-8kDa) > high molecular weight chitosan (CS-30kDa) > Poloxamer > sodium dodecyl sulfate (SDS) > sodium deoxycholate (SDCh). The results indicate that the chitosan nanoparticles can improve intestinal absorption of NCTD. PMID:22619530

Bei, Yong-yan; Chen, Xiao-yan; Liu, Yang; Xu, Jing-yu; Wang, Wen-juan; Gu, Zong-lin; Xing, Kong-lang; Zhu, Ai-jun; Chen, Wei-liang; Shi, Lin-seng; Wang, Qin; Zhang, Xue-nong; Zhang, Qiang

2012-01-01

9

Preparation and In vitro Investigation of Chitosan Compressed Tablets for Colon Targeting  

PubMed Central

Purpose: The aim of the present study was minimizing the drug release in upper gastro intestinal tract and targeting to colon by using the principles of compression coat. Methods: Compression coated tablets of Ibuprofen were prepared by direct compression method using chitosan (300, 250, 200 & 175 mg). Tablets were evaluated for their physicochemical properties and in vitro drug release studies. In vitro drug release studies were performed with and without rat caecal contents. Results: In the rat caecal contents tablets showed enhanced drug release due to degradation of chitosan coat by colonic colonic enzymes. The in vitro release studies in pH-6.8 phosphate buffer containing 2% w/v of rat caecal contents showed the cumulative percentage release of Ibuprofen after 26h as 31.94% ±0.59, 67.89% ± 0.45 and 55.87 % ± 0.45 and 82.52 % ± 0.92 respectively. Coat thickness and amount of chitosan controls the release rate. Formulations are best fitted with Korsmeyer-Peppas kinetics and mechanism of drug release was non-Fickian. FTIR studies reveals there is no drug-polysaccharide interaction. F1 formulation was a promising system for drug targeting to colon. Conclusion: Based on the obtained results chitosan as a press coat could target ibuprofen to the colon. PMID:24312762

Bashardoust, Negar; Jenita, Josephine Leno; Zakeri-Milani, Parvin

2011-01-01

10

Targeted MRI and optical molecular imaging using gadolinium loaded small unilamellar vesicles  

Microsoft Academic Search

Noninvasive investigation of cellular and molecular processes becomes possible through the novel techniques, one of which is molecular imaging, where enhanced sensitivity is a key component for clinic translation of the technique. In this presentation, spontaneously forming, small unilamellar vesicles (ULVs) (30 nm in diameter) were used as a platform to build a bi-modal [i.e., optical and Magnetic Resonance Imaging

U. a Iqbal; H. a Albaghdadi; M.-P. b Nieh; U. I. c Tuor; Z.d Mester; D. a Stanimirovic; J. e f Katsaras; A. a Abulrob

2011-01-01

11

Water-soluble derivatives of chitosan as a target delivery system of 99m Tc to some organs in vivo for nuclear imaging and biodistribution  

Microsoft Academic Search

Carboxymethyl chitosan, (CMC), and N-lauryl-carboxymethyl chitosan (LCMC), have been prepared as water soluble derivatives of chitosan. These biodegradable chitosan\\u000a derivatives were characterized and investigated for nuclear imaging and body distribution. They were labeled with 99mTc to use them as targeted delivery to some organs in vivo for nuclear imaging and to follow their biodistribution within\\u000a the body. The factors controlling

Dalia L. Hawary; Mohamed A. Motaleb; Hamed Farag; Osiris W. Guirguis; Maher Z. Elsabee

12

Chitosan-based macrophage-mediated drug targeting for the treatment of experimental visceral leishmaniasis.  

PubMed

The potential of chitosan microparticles as a carrier of doxorubicin for the treatment of visceral leishmaniasis was evaluated by macrophage-mediated drug targeting approach. Cationic charge of doxorubicin was masked by complexing it with dextran sulphate (a poly anion) in order to facilitate its incorporation into cationic chitosan microparticles. Prior to in vitro and in vivo studies, characterization studies were carried out systematically: particle size (?1.049?µm), surface morphology (fluorescence microscopy - spherical structured microparticles), Fourier transform infrared spectroscopy (to characterize effective cross-linking) and differential scanning calorimetry. In vitro studies were carried out in J774.1 in order to check the effective endocytotic uptake of microparticles by macrophages. In vivo studies were conducted in Syrian golden hamsters as per well-established protocols and the results drawn from in vivo studies displayed substantial reduction in leishmanial parasite load for doxorubicin-encapsulated chitosan microparticles: ?78.2?±?10.4%, when compared to the control (free doxorubicin): 33.3?±?2.4%. PMID:21545321

Kunjachan, Sijumon; Gupta, Swati; Dwivedi, Anil K; Dube, Anuradha; Chourasia, Manish K

2011-01-01

13

Formulation and evaluation of chitosan microspheres of aceclofenac for colon-targeted drug delivery.  

PubMed

The objective of this investigation was to develop novel colon specific drug delivery. Aceclofenac, a NSAID, was successfully encapsulated into chitosan microspheres. Various formulations were prepared by varying the ratio of chitosan, span-85 and stirring speed and the amount of glutaraldehyde. The SEM study showed that microspheres have smooth surfaces. Microspheres were characterised by Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) to confirm the absence of chemical interactions between drug and polymer and to know the formation of microspheres structure. The microspheres were evaluated for particle size, encapsulation efficiency, drug loading capacity, mucoadhesion studies, stability studies, in vitro and in vivo drug release studies. Particle sizes, as measured by the laser light scattering technique, were of an average size in the range 41-80?µm. The swelling index was in the range 0.37-0.82 and the entrapment efficiency range was 51-75% for all the formulations. The optimised batch ACM(13) released 83.6% at 8?h and 104% at 24?h in SCF containing rat caecal content. Eudragit coated chitosan microspheres prevented the release of the aceclofenac in the physiological environment of the stomach and small intestine and released 95.9±0.34% in the colon. With regard to release kinetics, the data were best fitted with the Higuchi model and showed zero order release with non-Fickian diffusion mechanism. The in vivo findings suggest that aceclofenac microspheres exhibit a prolonged effect of aceclofenac in rats and produce a significant anti-inflammatory effect. The findings of the present study conclusively state that chitosan microspheres are promising for colon targeting of aceclofenac to synchronise with chronobiological symptoms of rheumatoid arthritis. PMID:20848388

Umadevi, S K; Thiruganesh, R; Suresh, S; Reddy, K Bhaskar

2010-10-01

14

Synthesis and characterization of pH-sensitive hydrogel composed of carboxymethyl chitosan for colon targeted delivery of ornidazole.  

PubMed

In the present study, carboxymethyl chitosan was prepared from chitosan, crosslinked with glutaraldehyde and evaluated in vitro as a potential carrier for colon targeted drug delivery of ornidazole. Ornidazole was incorporated at the time of crosslinking of carboxymethyl chitosan. The chitosan was evaluated for its degree of deacetylation (DD) and average molecular weight; which were found to be 84.6% and 3.5×10(4) Da, respectively. The degree of substitution on prepared carboxymethyl chitosan was found to be 0.68. All hydrogel formulations showed more than 85% and 74% yield and drug loading, respectively. The swelling behaviour of prepared hydrogels checked in different pH values, 1.2, 6.8 and 7.4, indicated pH responsive swelling characteristic with very less swelling at pH 1.2 and quick swelling at pH 6.8 followed by linear swelling at pH 7.4 with slight increase. In vitro release profile was carried out at the same conditions as in swelling and drug release was found to be dependant on swelling of hydrogels and showed biphasic release pattern with non-fickian diffusion kinetics at higher pH. The carboxymethylation of chitosan, entrapment of drug and its interaction in prepared hydrogels were checked by FTIR, (1)H NMR, DSC and p-XRD studies, which confirmed formation of carboxymethyl chitosan from chitosan and absence of any significant chemical change in ornidazole after being entrapped in crosslinked hydrogel formulations. The surface morphology of formulation S6 checked before and after dissolution, revealed open channel like pores formation after dissolution. PMID:22099382

Vaghani, Subhash S; Patel, Madhabhai M; Satish, C S

2012-01-10

15

The liver-targeting study of the N-galactosylated chitosan in vivo and in vitro.  

PubMed

Abstract In order to study the liver targeting of the N-galactosylated chitosan (GC) polymer in liver, we first conjugated the lactobionic acid with chitosan (CS) to obtain the carrier of GC with different degree of substitution of lactosyl group. Western blot was performed to detect the expression levels of the asialoglycoprotein receptors (ASGPR) in the cell lines of HepG2, SMMC-7721, and HL-7702. The protein level of ASGPR was lower in HepG2 compared to HL-7702 and SMMC-7721. Although all treated by CS, viabilities of HL-7702 and HepG2 did not experience any significant drop, while viability of SMMC-7721 decreased 15% on average from control. It was the first data about the inhibitory effect of GC on the liver cells. Fluorescein isothiocyanate (FITC) labeled GC (GC-FITC) was injected intravenously into mice at a dose of 0.02 ?mol/mouse. GC-FITC showed maximum liver localization at 5 min and even detectable at 48 h after injection. Further, the accumulation of GC in liver was about 5.4-fold higher than that of CS. In conclusion, GC demonstrated its higher efficacy in drug liver targeting and thus could be a more promising drug or gene carrier in future therapies. PMID:24066968

Liang, Meihao; Zheng, Xiaoliang; Tu, Linglan; Ma, Zhen; Wang, Zunyuan; Yan, Dongmei; Shen, Zhengrong

2014-12-01

16

Antimicrobial and anti-inflammatory activity of chitosan-alginate nanoparticles: a targeted therapy for cutaneous pathogens.  

PubMed

Advances in nanotechnology have demonstrated potential application of nanoparticles (NPs) for effective and targeted drug delivery. Here we investigated the antimicrobial and immunological properties and the feasibility of using NPs to deliver antimicrobial agents to treat a cutaneous pathogen. NPs synthesized with chitosan and alginate demonstrated a direct antimicrobial activity in vitro against Propionibacterium acnes, the bacterium linked to the pathogenesis of acne. By electron microscopy (EM) imaging, chitosan-alginate NPs were found to induce the disruption of the P. acnes cell membrane, providing a mechanism for the bactericidal effect. The chitosan-alginate NPs also exhibited anti-inflammatory properties as they inhibited P. acnes-induced inflammatory cytokine production in human monocytes and keratinocytes. Furthermore, benzoyl peroxide (BP), a commonly used antiacne drug, was effectively encapsulated in the chitosan-alginate NPs and demonstrated superior antimicrobial activity against P. acnes compared with BP alone while demonstrating less toxicity to eukaryotic cells. Together, these data suggest the potential utility of topical delivery of chitosan-alginate NP-encapsulated drug therapy for the treatment of dermatologic conditions with infectious and inflammatory components. PMID:23190896

Friedman, Adam J; Phan, Jenny; Schairer, David O; Champer, Jackson; Qin, Min; Pirouz, Aslan; Blecher-Paz, Karin; Oren, Ami; Liu, Phil T; Modlin, Robert L; Kim, Jenny

2013-05-01

17

Reversion of multidrug resistance by tumor targeted delivery of antisense oligodeoxynucleotides in hydroxypropyl-chitosan nanoparticles.  

PubMed

Chitosan and its derivatives have shown great potential as non-viral vectors for gene delivery therapy. Folic acid receptor (FR) is an important anti-cancer therapy target that is applicable to many cancer types. In this study, we developed an efficient and targeted delivery of antisense oligodeoxynucleotides asODNs, using folic acid (FA) conjugated hydroxypropyl-chitosan (HPCS). These nanoparticles were designed to reduce production of P-gp, in order to overcome tumor drug resistance. Nanoparticles prepared were found to be 181 nm in diameter. Spectrofluorimetry was utilized to evaluate the effect of charge ratio of the nanoparticles on loading efficiency. In PBS buffer, 40% of asODNs were released from the nanoparticles at first 24 h. However, just another 15% was released between 24 and 48 h. The antitumor effect of the nanoparticles was evaluated in KB-A-1 cells implanted in Balb/c-nu/nu mice. They inhibited the growth of tumor by 35% compared to the bare asODNs. The FA-HPCS-asODNs nanoparticles demonstrated significantly inhibition of the multi drug resistance (MDR) 1 gene levels and P-gp levels in vitro and in vivo, respectively, related with bare asODNs and HPCS-asODNs ones. During in vivo studies, FA-HPCS-asODNs nanoparticles were also found to bind specifically and efficiently to FR high-expressing cancer cells. These results suggested that the use of targeted, antisense agent nanoparticles would be potential approach to overcome tumor drug resistance. PMID:20188412

Wang, Jiaqi; Tao, Xinyi; Zhang, Yufei; Wei, Dongzhi; Ren, Yuhong

2010-05-01

18

Chitosan cross-linked docetaxel loaded EGF receptor targeted nanoparticles for lung cancer cells.  

PubMed

Lung cancer, associated with the up-regulated epidermal growth factor receptor (EGFR) led to the development of EGFR targeted anticancer therapeutics. The biopolymeric nanoparticles form an outstanding system for the targeted delivery of therapeutic agents. The present work evaluated the in vitro effects of chitosan cross-linked ?-poly(glutamic acid) (?-PGA) nanoparticles (Nps) loaded with docetaxel (DTXL) and decorated with Cetuximab (CET), targeted to EGFR over-expressing non-small-cell-lung-cancer (NSCLC) cells (A549). CET-DTXL-?-PGA Nps was prepared by ionic gelation and CET conjugation via EDC/NHS chemistry. EGFR specificity of targeted Nps was confirmed by the higher uptake rates of EGFR +ve A549 cells compared to that of EGFR -ve cells (NIH3T3). The cytotoxicity of Nps quantified using cell based (MTT/LDH) and flowcytometry (Cell-cycle analysis, Annexin V/PI and JC-1) assays showed superior antiproliferative activity of CET-DTXL-?-PGA Nps over DTXL-?-PGA Nps. The A549 cells treated with CET-DTXL-?-PGA NPs underwent a G2/M phase cell cycle arrest followed by reduction in mitochondrial membrane potential of A549 cells, inducing apoptosis and necrosis resulting in enhanced cancer cell death. CET-DTXL-?-PGA Nps exhibited enhanced cellular internalization and therapeutic activity, by actively targeting EGFR on NSCLC cells and hence could be an effective alternative to non-specific, conventional chemotherapy by increasing its efficiency by many folds. PMID:24950310

Maya, S; Sarmento, Bruno; Lakshmanan, Vinoth-Kumar; Menon, Deepthy; Seabra, Vitor; Jayakumar, R

2014-08-01

19

MUC1 aptamer conjugated to chitosan nanoparticles, an efficient targeted carrier designed for anticancer SN38 delivery.  

PubMed

Molecularly targeted therapy is of great interest for diagnosis and treatment of cancerous cells due to its low toxicity for normal cells. In this study, chitosan was utilized as a promising carrier for delivery, and aptamer (Apt) was employed for active targeting of SN38 to colon cancer. SN38 cannot be used clinically due to its poor solubility and high toxicity. Developing nanoparticles (NPs) of drug-polymer conjugates can be a good candidate for overcoming such problems. N-Carboxyethyl chitosan ester (CS-EA) was synthesized as an intermediate for conjugation of SN38 to chitosan. MUC1 DNA aptamer with 5'-NH2 functional group was conjugated to the self-assembled conjugate as a targeting agent. Prepared NPs had smooth and spherical morphology with 200 nm particle size. Conjugation of aptamer was confirmed by gel electrophoresis. In vitro cytotoxicity of NPs was assessed by HT-29 as MUC1 positive cell line through MTT assay. Aptamer conjugated NPs (Apt NPs) were more toxic than non-targeted NPs, however they were as toxic as free drug. Cellular uptake and targeting ability of prepared NPs were also confirmed via confocal microscopy. As a conclusion, prepared CS-SN38-Apt NPs can increase efficacy of drug SN38 through increasing solubility and specific delivery to the target tissue. PMID:24905777

Sayari, E; Dinarvand, M; Amini, M; Azhdarzadeh, M; Mollarazi, E; Ghasemi, Z; Atyabi, F

2014-10-01

20

Pectin-coated chitosan-LDH bionanocomposite beads as potential systems for colon-targeted drug delivery.  

PubMed

This work introduces results on a new drug delivery system (DDS) based on the use of chitosan/layered double hydroxide (LDH) biohybrid beads coated with pectin for controlled release in the treatment of colon diseases. Thus, the 5-aminosalicylic acid (5ASA), the most used non-steroid-anti-inflammatory drug (NSAID) in the treatment of ulcerative colitis and Crohn's disease, was chosen as model drug aiming to a controlled and selective delivery in the colon. The pure 5ASA drug and the hybrid material prepared by intercalation in a layered double hydroxide of Mg2Al using the co-precipitation method, were incorporated in a chitosan matrix in order to profit from its mucoadhesiveness. These compounds processed as beads were further treated with the polysaccharide pectin to create a protective coating that ensures the stability of both chitosan and layered double hydroxide at the acid pH of the gastric fluid. The resulting composite beads presenting the pectin coating are stable to water swelling and procure a controlled release of the drug along their passage through the simulated gastrointestinal tract in in vitro experiments, due to their resistance to pH changes. Based on these results, the pectin@chitosan/LDH-5ASA bionanocomposite beads could be proposed as promising candidates for the colon-targeted delivery of 5ASA, with the aim of acting only in the focus of the disease and minimizing side effects. PMID:24374607

Ribeiro, Lígia N M; Alcântara, Ana C S; Darder, Margarita; Aranda, Pilar; Araújo-Moreira, Fernando M; Ruiz-Hitzky, Eduardo

2014-03-10

21

Both FA- and mPEG-conjugated chitosan nanoparticles for targeted cellular uptake and enhanced tumor tissue distribution  

NASA Astrophysics Data System (ADS)

Both folic acid (FA)- and methoxypoly(ethylene glycol) (mPEG)-conjugated chitosan nanoparticles (NPs) had been designed for targeted and prolong anticancer drug delivery system. The chitosan NPs were prepared with combination of ionic gelation and chemical cross-linking method, followed by conjugation with both FA and mPEG, respectively. FA-mPEG-NPs were compared with either NPs or mPEG-/FA-NPs in terms of their size, targeting cellular efficiency and tumor tissue distribution. The specificity of the mPEG-FA-NPs targeting cancerous cells was demonstrated by comparative intracellular uptake of NPs and mPEG-/FA-NPs by human adenocarcinoma HeLa cells. Mitomycin C (MMC), as a model drug, was loaded to the mPEG-FA-NPs. Results show that the chitosan NPs presented a narrow-size distribution with an average diameter about 200 nm regardless of the type of functional group. In addition, MMC was easily loaded to the mPEG-FA-NPs with drug-loading content of 9.1%, and the drug releases were biphasic with an initial burst release, followed by a subsequent slower release. Laser confocal scanning imaging proved that both mPEG-FA-NPs and FA-NPs could greatly enhance uptake by HeLa cells. In vivo animal experiments, using a nude mice xenograft model, demonstrated that an increased amount of mPEG-FA-NPs or FA-NPs were accumulated in the tumor tissue relative to the mPEG-NPs or NPs alone. These results suggest that both FA- and mPEG-conjugated chitosan NPs are potentially prolonged drug delivery system for tumor cell-selective targeting treatments.

Hou, Zhenqing; Zhan, Chuanming; Jiang, Qiwei; Hu, Quan; Li, Le; Chang, Di; Yang, Xiangrui; Wang, Yixiao; Li, Yang; Ye, Shefang; Xie, Liya; Yi, Yunfeng; Zhang, Qiqing

2011-10-01

22

An inhalable ??-adrenoceptor ligand-directed guanidinylated chitosan carrier for targeted delivery of siRNA to lung.  

PubMed

SiRNA-based strategies appear to be an exciting new approach for the treatment of respiratory diseases. To extrapolate siRNA-mediated interventions from bench to bedside in this area, several aspects have to be jointly considered, including a safe and efficient gene carrier with pulmonary deposition efficiency, as well as in vivo method for siRNA/nanoparticles delivery. Accordingly, in this work, (i) a non-viral DNA vector, guanidinylated chitosan (GCS) that has been developed in our previous study [X.Y. Zhai, P. Sun, Y.F. Luo, C.N. Ma, J. Xu, W.G. Liu, 2011], was tested for siRNA delivery. We demonstrated that GCS was able to completely condense siRNA at weight ratio 40:1, forming nanosize particles of diameter ~100 nm, 15 mV in surface potential. Guanidinylation of chitosan not only decreased the cytotoxicity but also facilitated cellular internalization of siRNA nanoparticles, leading to an enhanced gene-silencing efficiency compared to the pristine chitosan (CS). (ii) We chemically coupled salbutamol, a ?(2)-adrenoceptor agonist, to GCS (SGCS), which successfully improved targeting specificity of the green fluorescent protein (GFP)-siRNA carrier to lung cells harbored with ?(2)-adrenergic receptor, and remarkably enhanced the efficacy of gene silence in vitro and in the lung of enhanced green fluorescent protein (EGFP)-transgenic mice in vivo. (iii) It was proved that this chitosan-based polymer was able to provide both the pDNA and siRNA with the protection against destructive shear forces generated by the mesh-based nebulizers. Aerosol treatment improved the nanoparticle size distribution, which should be in favor of enhancing the transfection efficiency. We suggest a potential application of the chitosan-derived nanodelivery vehicle (SGCS) in RNA interference therapy for lung diseases via aerosol inhalation. PMID:22698944

Luo, Yongfeng; Zhai, Xinyun; Ma, Chaonan; Sun, Peng; Fu, Zhiping; Liu, Wenguang; Xu, Jun

2012-08-20

23

TNYL peptide functional chitosan-g-stearate conjugate micelles for tumor specific targeting.  

PubMed

Nowadays, a real challenge in cancer therapy is to design drug delivery systems that can achieve high concentrations of drugs at the target site for improved therapeutic effect with reduced side effects. In this research, we designed and synthesized a homing peptide-(TNYLFSPNGPIA, TNYL) modified chitosan-g-stearate (CS) polymer micelle (named T-CS) for targeting delivery. The peptide displayed specific binding affinity to EphB4 which is a member of the Eph family of receptor tyrosine protein kinases. The amphiphilic polymer T-CS can gather into micelles by themselves in an aqueous environment with a low critical micelle concentration value (91.2 ?g/L) and nano-scaled size (82.1±2.8 nm). The drug encapsulation efficiency reached 86.43% after loading the hydrophobic drug doxorubicin (DOX). The cytotoxicity of T-CS/DOX against SKOV3 cells was enhanced by approximately 2.3-fold when compared with CS/DOX. The quantitative and qualitative analysis for cellular uptake indicated that TNYL modification can markedly increase cellular internalization in the EphB4-overexpressing SKOV3 cell line, especially with a short incubation time. It is interesting that relatively higher uptake of the T-CS/DOX micelles by SKOV3 cells (positive-EphB4) than A549 cells (negative-EphB4) was observed when the two cells were co-incubated. Furthermore, in vivo distribution experiment using a bilateral-tumor model showed that there was more fluorescence accumulation in the SKOV3 tumor than in the A549 tumor over the whole experiment. These results suggest that TNYL-modified CS micelles may be promising drug carriers as targeting therapy for the EphB4-overexpressing tumor. PMID:25298734

Chen, Feng-Ying; Yan, Jing-Jing; Yi, Han-Xi; Hu, Fu-Qiang; Du, Yong-Zhong; Yuan, Hong; You, Jian; Zhao, Meng-Dan

2014-01-01

24

TNYL peptide functional chitosan-g-stearate conjugate micelles for tumor specific targeting  

PubMed Central

Nowadays, a real challenge in cancer therapy is to design drug delivery systems that can achieve high concentrations of drugs at the target site for improved therapeutic effect with reduced side effects. In this research, we designed and synthesized a homing peptide-(TNYLFSPNGPIA, TNYL) modified chitosan-g-stearate (CS) polymer micelle (named T-CS) for targeting delivery. The peptide displayed specific binding affinity to EphB4 which is a member of the Eph family of receptor tyrosine protein kinases. The amphiphilic polymer T-CS can gather into micelles by themselves in an aqueous environment with a low critical micelle concentration value (91.2 ?g/L) and nano-scaled size (82.1±2.8 nm). The drug encapsulation efficiency reached 86.43% after loading the hydrophobic drug doxorubicin (DOX). The cytotoxicity of T-CS/DOX against SKOV3 cells was enhanced by approximately 2.3-fold when compared with CS/DOX. The quantitative and qualitative analysis for cellular uptake indicated that TNYL modification can markedly increase cellular internalization in the EphB4-overexpressing SKOV3 cell line, especially with a short incubation time. It is interesting that relatively higher uptake of the T-CS/DOX micelles by SKOV3 cells (positive-EphB4) than A549 cells (negative-EphB4) was observed when the two cells were co-incubated. Furthermore, in vivo distribution experiment using a bilateral-tumor model showed that there was more fluorescence accumulation in the SKOV3 tumor than in the A549 tumor over the whole experiment. These results suggest that TNYL-modified CS micelles may be promising drug carriers as targeting therapy for the EphB4-overexpressing tumor.

Chen, Feng-Ying; Yan, Jing-Jing; Yi, Han-Xi; Hu, Fu-Qiang; Du, Yong-Zhong; Yuan, Hong; You, Jian; Zhao, Meng-Dan

2014-01-01

25

Galactosylated Chitosan Oligosaccharide Nanoparticles for Hepatocellular Carcinoma Cell-Targeted Delivery of Adenosine Triphosphate  

PubMed Central

Nanoparticles composed of galactosylated chitosan oligosaccharide (Gal-CSO) and adenosine triphosphate (ATP) were prepared for hepatocellular carcinoma cell-specific uptake, and the characteristics of Gal-CSO/ATP nanoparticles were evaluated. CSO/ATP nanoparticles were prepared as a control. The average diameter and zeta potential of Gal-CSO/ATP nanoparticles were 51.03 ± 3.26 nm and 30.50 ± 1.25 mV, respectively, suggesting suitable properties for a drug delivery system. Subsequently, the cytotoxicity of Gal-CSO/ATP nanoparticles were examined by the methyl tetrazolium (MTT) assay, and the half maximal inhibitory concentration (IC50) values were calculated with HepG2 (human hepatocellular carcinoma cell line) cells. The results showed that the cytotoxic effect of nanoparticles on HepG2 cells was low. In the meantime, it was also found that the Gal-CSO/ATP nanoparticles could be uptaken by HepG2 cells, due to expression of the asialoglycoprotein receptor (ASGP-R) on their surfaces. The presented results indicate that the Gal-CSO nanoparticles might be very attractive to be used as an intracellular drug delivery carrier for hepatocellular carcinoma cell targeting, thus warranting further in vivo or clinical investigations. PMID:23899789

Zhu, Xiu Liang; Du, Yong Zhong; Yu, Ri Sheng; Liu, Ping; Shi, Dan; Chen, Ying; Wang, Ying; Huang, Fang Fang

2013-01-01

26

Preparation and characterization of gadolinium-loaded PLGA particles surface modified with RGDS for the detection of thrombus  

PubMed Central

Thrombotic disease is a leading cause of death and disability worldwide. The development of magnetic resonance molecular imaging provides potential promise for early disease diagnosis. In this study, we explore the preparation and characterization of gadolinium (Gd)-loaded poly (lactic-co-glycolic acid) (PLGA) particles surface modified with the Arg-Gly-Asp-Ser (RGDS) peptide for the detection of thrombus. PLGA was employed as the carrier-delivery system, and a double emulsion solvent-evaporation method (water in oil in water) was used to prepare PLGA particles encapsulating the magnetic resonance contrast agent Gd diethylenetriaminepentaacetic acid (DTPA). To synthesize the Gd-PLGA/chitosan (CS)-RGDS particles, carbodiimide-mediated amide bond formation was used to graft the RGDS peptide to CS to form a CS-RGDS film that coated the surface of the PLGA particles. Blank PLGA, Gd-PLGA, and Gd-PLGA/CS particles were fabricated using the same water in oil in water method. Our results indicated that the RGDS peptide successfully coated the surface of the Gd-PLGA/CS-RGDS particles. The particles had a regular shape, smooth surface, relatively uniform size, and did not aggregate. The high electron density of the Gd-loaded particles and a translucent film around the particles coated with the CS and CS-RGDS films could be observed by transmission electron microscopy. In vitro experiments demonstrated that the Gd-PLGA/CS-RGDS particles could target thrombi and could be imaged using a clinical magnetic resonance scanner. Compared with the Gd-DTPA solution, the longitudinal relaxation time of the Gd-loaded particles was slightly longer, and as the Gd-load concentration increased, the longitudinal relaxation time values decreased. These results suggest the potential of the Gd-PLGA/CS-RGDS particles for the sensitive and specific detection of thrombus at the molecular level. PMID:24124363

Zhang, Yu; Zhou, Jun; Guo, Dajing; Ao, Meng; Zheng, Yuanyi; Wang, Zhigang

2013-01-01

27

Norcantharidin-associated galactosylated chitosan nanoparticles for hepatocyte-targeted delivery  

Microsoft Academic Search

In this study a new chitosan (CS) derivative, galactosylated chitosan (GC), was synthesized and used to prepare norcantharidin-associated GC nanoparticles (NCTD-GC NPs) by taking advantage of the ionic cross-linkage between the molecules of the anti-hepatocarcinoma medicine NCTD and of the GC as carrier. NCTD-GC NPs were obtained with average particle size of 118.68 ± 3.37 nm, entrapment efficiency of 57.92

Qin Wang; Liang Zhang; Wei Hu; Zhan-Hong Hu; Yong-Yan Bei; Jing-Yu Xu; Wen-Juan Wang; Xue-Nong Zhang; Qiang Zhang

2010-01-01

28

Venlafaxine loaded chitosan NPs for brain targeting: pharmacokinetic and pharmacodynamic evaluation.  

PubMed

The purpose of the present investigation was to prepare venlafaxine (VLF) loaded chitosan nanoparticles (NPs) to enhance the uptake of VLF to brain via intranasal (i.n.) delivery. VLF loaded chitosan NPs were prepared and characterized for particle size, size distribution, zeta potential, encapsulation efficiency and in vitro drug release. In order to investigate the localization of chitosan NPs in brain and other organs qualitatively confocal laser scanning microscopy technique was carried out using rhodamine-123 (ROD-123) as marker. The levels of VLF in plasma and brain tissues were also determined, the brain/blood ratios of VLF for VLF (i.v.), VLF (i.n.), VLF chitosan NPs (i.n.) were 0.0293, 0.0700 and 0.1612, respectively, at 0.5h, indicative of better brain uptake of VLF chitosan NPs. The higher drug transport efficiency (508.59) and direct transport percentage (80.34) of VLF chitosan NPs as compared to other formulations suggest its better efficacy in treatment of depression. PMID:24750606

Haque, Shadabul; Md, Shadab; Fazil, Mohammad; Kumar, Manish; Sahni, Jasjeet Kaur; Ali, Javed; Baboota, Sanjula

2012-06-01

29

Efficient Nonviral Gene Therapy Using Folate-Targeted Chitosan-DNA Nanoparticles In Vitro  

PubMed Central

Nonviral cationic polymers like chitosan can be combined with DNA to protect it from degradation. The chitosan is a biocompatible, biodegradable, nontoxic, and cheap polycationic polymer with low immunogenicity. The objective of this study was to synthesize and then assess different chitosan-DNA nanoparticles and to select the best ones for selective in vitro transfection in human epidermoid carcinoma (KB) cell lines. It revealed that different combinations of molecular weight, the presence or absence of folic acid ligand, and different plasmid DNA sizes can lead to nanoparticles with various diameters and diverse transfection efficiencies. The intracellular trafficking, nuclear uptake, and localization are also studied by confocal microscopy, which confirmed that DNA was delivered to cell nuclei to be expressed. PMID:22474605

Jreyssaty, Christian; Shi, Qin; Wang, Huijie; Qiu, Xingping; Winnik, Francoise M.; Zhang, Xiaoling; Dai, Kerong; Benderdour, Mohamed; Fernandes, Julio C.

2012-01-01

30

The targeted behavior of folate-decorated N-succinyl-N'-octyl chitosan evaluated by NIR system in mouse model  

NASA Astrophysics Data System (ADS)

The development of more selective delivery systems for cancer diagnosis and chemotherapy is one of the most important goals of current anticancer research. The purpose of this study is to construct and evaluate the folate-decorated, self-assembled nanoparticles as candidates to deliver near infrared fluorescent dyes into tumors and to investigate the mechanisms underlying the tumor targeting with folate-decorated, self-assembled nanoparticles. Folate-decorated N-succinyl-N'-octyl chitosan (folate-SOC) were synthesized. The chemical modification chitosan could self-assemble into stable micelles in aqueous medium. Micelle size determined by size analysis was around 140 nm in a phosphate-buffered saline (PBS, PH 7.4). Folate-SOC could maintain their structure for up to 15 days in PBS. Near infrared dye ICG-Der-01 as a mode drug was loaded in the micelles, and the entrapment efficiency (EE) and drug loading (DL) were investigated. The targeted behavior of folate-SOC was evaluated by near-infrared fluorescence imaging in vivo on different groups of denuded mice, with A549 or Bel-7402 tumors. The optical imaging results indicated that folated-decorated SOC showed an excellent tumor specificity in Bel-7402 tumor-bearing mice, and weak tumor specificity in A549 tumor bearing mice. We believe that this work can provide insight for the engineering of nanoparticles and be extended to cancer therapy and diagnosis so as to deliver multiple therapeutic agents and imaging probes at high local concentrations.

Zhu, Hongyan; Deng, Dawei; Chen, Haiyan; Qian, Zhiyu; Gu, Yueqing

2010-11-01

31

Disruption of Aedes aegypti Olfactory System Development through Chitosan/siRNA Nanoparticle Targeting of semaphorin-1a  

PubMed Central

Despite the devastating impact of mosquito-borne illnesses on human health, surprisingly little is known about mosquito developmental biology, including development of the olfactory system, a tissue of vector importance. Analysis of mosquito olfactory developmental genetics has been hindered by a lack of means to target specific genes during the development of this sensory system. In this investigation, chitosan/siRNA nanoparticles were used to target semaphorin-1a (sema1a) during olfactory system development in the dengue and yellow fever vector mosquito Aedes aegypti. Immunohistochemical analyses and anterograde tracing of antennal sensory neurons, which were used to track the progression of olfactory development in this species, revealed antennal lobe defects in sema1a knockdown fourth instar larvae. These findings, which correlated with a larval odorant tracking behavioral phenotype, identified previously unreported roles for Sema1a in the developing insect larval olfactory system. Analysis of sema1a knockdown pupae also revealed a number of olfactory phenotypes, including olfactory receptor neuron targeting and projection neuron defects coincident with a collapse in the structure and shape of the antennal lobe and individual glomeruli. This study, which is to our knowledge the first functional genetic analysis of insect olfactory development outside of D. melanogaster, identified critical roles for Sema1a during Ae. aegypti larval and pupal olfactory development and advocates the use of chitosan/siRNA nanoparticles as an effective means of targeting genes during post-embryonic Ae. aegypti development. Use of siRNA nanoparticle methodology to understand sensory developmental genetics in mosquitoes will provide insight into the evolutionary conservation and divergence of key developmental genes which could be exploited in the development of both common and species-specific means for intervention. PMID:23696908

Mysore, Keshava; Flannery, Ellen M.; Tomchaney, Michael; Severson, David W.; Duman-Scheel, Molly

2013-01-01

32

Mad2 checkpoint gene silencing using epidermal growth factor receptor-targeted chitosan nanoparticles in non-small cell lung cancer model.  

PubMed

RNA interference has emerged as a powerful strategy in cancer therapy because it allows silencing of specific genes associated with tumor progression and resistance. Mad2 is an essential mitotic checkpoint component required for accurate chromosome segregation during mitosis, and its complete abolition leads to cell death. We have developed an epidermal growth factor receptor (EGFR)-targeted chitosan system for silencing the Mad2 gene as a strategy to efficiently induce cell death in EGFR overexpressing human A549 non-small cell lung cancer cells. Control and EGFR-targeted chitosan nanoparticles loaded with small interfering RNAs (siRNAs) against Mad2 were formulated and characterized for size, charge, morphology, and encapsulation efficiency. Qualitative and quantitative intracellular uptake studies by confocal imaging and flow cytometry, respectively, showed time-dependent enhanced and selective intracellular internalization of EGFR-targeted nanoparticles compared to nontargeted system. Targeted nanoparticles showed nearly complete depletion of Mad2 expression in A549 cells contrasting with the partial depletion in the nontargeted system. Accordingly, Mad2-silencing-induced apoptotic cell death was confirmed by cytotoxicity assay and flow cytometry. Our results demonstrate that EGFR-targeted chitosan loaded with Mad2 siRNAs is a potent delivery system for selective killing of cancer cells. PMID:25256346

Nascimento, Ana Vanessa; Singh, Amit; Bousbaa, Hassan; Ferreira, Domingos; Sarmento, Bruno; Amiji, Mansoor M

2014-10-01

33

Docetaxel-Loaded Chitosan Microspheres as a Lung Targeted Drug Delivery System: In Vitro and in Vivo Evaluation  

PubMed Central

The aim of this study was to prepare docetaxel-loaded chitosan microspheres and to evaluate their in vitro and in vivo characteristics. Glutaraldehyde crosslinked microspheres were prepared using a water-in-oil emulsification method, and characterized in terms of the morphological examination, particle size distribution, encapsulation ratio, drug-loading coefficient and in vitro release. Pharmacokinetics and biodistribution studies were used to evaluate that microspheres have more advantage than the conventional formulations. The emulsion crosslinking method was simple to prepare microspheres and easy to scale up. The formed microspheres were spherical in shape, with a smooth surface and the size was uniform (9.6 ± 0.8 ?m); the encapsulation efficiency and drug loading of prepared microspheres were 88.1% ± 3.5% and 18.7% ± 1.2%, respectively. In vitro release indicated that the DTX microspheres had a well-sustained release efficacy and in vivo studies showed that the microspheres were found to release the drug to a maximum extent in the target tissue (lung). The prepared microspheres were found to possess suitable physico-chemical properties and the particle size range. The sustained release of DTX from microspheres revealed its applicability as drug delivery system to minimize the exposure of healthy tissues while increasing the accumulation of therapeutic drug in target sites. PMID:24577314

Wang, Hao; Xu, Yongdong; Zhou, Xiao

2014-01-01

34

Characterization of a Conjugate between Rose Bengal and Chitosan for Targeted Antibiofilm and Tissue Stabilization Effects as a Potential Treatment of Infected Dentin  

PubMed Central

Bacterial biofilms and dentin structural changes are some of the major challenges in the management of infected dentin tissue. This study characterized a photosensitizer-conjugated chitosan with enhanced photodynamic efficacy against dental biofilms, as well as the ability to reinforce the postinfected dentin matrix in order to improve its mechanical and chemical stability. Rose Bengal-conjugated chitosan (CSRB) was synthesized using a chemical cross-linking method and characterized for photophysical, photobiological, and cytotoxicity properties. Its potential as an antibacterial and matrix-reinforcing agent on dentin collagen was also evaluated. Enterococcus faecalis as planktonic and in vitro biofilms was treated with CSRB and photodynamically activated with 5 to 60 J/cm2 green light. Dentin collagen was used for the CSRB cross-linking experiments and evaluated for chemical changes, resistance to enzymatic degradation, and mechanical properties. CSRB was a photosensitizer with efficient singlet oxygen yield. In vitro photoactivation gave higher fibroblast cell survival than did RB alone. CSRB showed significant antibiofilm photoinactivation (P < 0.01). The CSRB-cross-linked dentin collagen showed higher resistance to collagenase degradation and superior mechanical properties (P < 0.05). In summary, the photoactivated CSRB particles synthesized in this study may be a synergistic multifunctional treatment approach with lower cytotoxicity and effective antibiofilm activity as well as the ability to reinforce the dentin collagen to enhance resistance to degradation and improve mechanical properties. This may be a targeted treatment strategy to deal with infected dentin hard tissues in a clinical scenario, where both disinfection and structural integrity need to be addressed concomitantly. PMID:22777042

Shrestha, Annie; Hamblin, Michael R.

2012-01-01

35

N-Succinyl-chitosan nanoparticles coupled with low-density lipoprotein for targeted osthole-loaded delivery to low-density lipoprotein receptor-rich tumors  

PubMed Central

N-Succinyl-chitosan (NSC) was synthesized and NSC nanoparticles (NPs) with loaded osthole (Ost) (Ost/NSC-NPs) were prepared by emulsion solvent diffusion. Subsequently, low-density lipoprotein (LDL)-mediated NSC-NPs with loaded Ost (Ost/LDL-NSC-NPs) were obtained by coupling LDL with Ost/NSC-NPs through amide linkage. The average particle size of Ost/NSC-NPs was approximately 145 nm, the entrapment efficiency was 78.28%±2.06%, and the drug-loading amount was 18.09%±0.17%. The release of Ost from Ost/NSC-NPs in vitro showed a more evident sustained effect than the native material. The half maximal inhibitory concentration of Ost/LDL-NSC-NPs was only 16.23% that of the free Ost at 24 hours in HepG2 cells. Ost inhibited HepG2 cell proliferation by arresting cells in the synthesis phase of the cell cycle and by triggering apoptosis. Cellular uptake and subcellular localization in vitro and near-infrared fluorescence real-time imaging in vivo showed that Ost/LDL-NSC-NPs had high targeting efficacy. Therefore, LDL-NSC-NPs are a promising system for targeted Ost delivery to liver tumor. PMID:24966673

Zhang, Chun-ge; Zhu, Qiao-ling; Zhou, Yi; Liu, Yang; Chen, Wei-liang; Yuan, Zhi-Qiang; Yang, Shu-di; Zhou, Xiao-feng; Zhu, Ai-jun; Zhang, Xue-nong; Jin, Yong

2014-01-01

36

Preliminary Study on Hepatocyte-Targeted Phosphorus-31 MRS Using ATP-Loaded Galactosylated Chitosan Oligosaccharide Nanoparticles  

PubMed Central

Background. The clinical applications of hepatic phosphorus-31 magnetic resonance spectroscopy (31P MRS) remain to be difficult because the changes of phosphates between normal hepatic tissues and pathological tissues are not so obvious, and furthermore, up to now there is few literature on hepatocyte-targeted 31P MRS. Materials and Methods. The ATP-loaded Gal-CSO (Gal-CSO/ATP) nanoparticles were prepared and the special cellular uptake of them as evaluated by using HepG-2 tumor cells and A549 tumor cells, respectively. Two kinds of cells were incubated with the nanoparticles suspension, respectively. Then were prepared the cell samples and the enhancement efficiency of ATP peaks detected by 31P MRS was evaluated. Results. The cellular uptake rate of Gal-CSO/ATP nanoparticles in HepG-2 cells was higher than that in A549 cells. Furthermore, the enlarged ATP peaks of Gal-CSO/ATP nanoparticles in HepG-2 cells were higher than those in A549 cells in vitro detected by 31P MRS. Conclusions. Gal-CSO/ATP nanoparticles have significant targeting efficiency in hepatic cells in vitro and enhancement efficiency of ATP peaks in HepG-2 cells. Furthermore, 31P MRS could be applied in the research of hepatic molecular imaging. PMID:24363667

Yu, Ri-Sheng; Zhu, Xiu-Liang; Sun, Jian-Zhong; Shi, Dan; Chen, Ying; Wang, Zhi-Kang; Tang, Ke-Zhong; Du, Yong-Zhong

2013-01-01

37

Effect of HPMC - E15 LV premium polymer on release profile and compression characteristics of chitosan/ pectin colon targeted mesalamine matrix tablets and in vitro study on effect of pH impact on the drug release profile.  

PubMed

The study was designed to investigate the in vitro dissolution profile and compression characteristics of colon targeted matrix tablets prepared with HPMC E15 LV in combination with pectin and Chitosan. The matrix tablets were subjected to two dissolution models in various simulated fluids such as pH 1.2, 6, 6.8, 7.2, 5.5. The fluctuations in colonic pH conditions during IBD (inflammatory bowel disease) and the nature of less fluid content in the colon may limit the expected drug release in the polysaccharide-based matrices when used alone. The Hydrophilic hydroxyl propyl methylcellulose ether premium polymer (HPMC E15 LV) of low viscosity grade was used in the formulation design, which made an excellent modification in physical and compression characteristics of the granules. The release studies indicated that the prepared matrices could control the drug release until the dosage form reaches the colon and the addition HPMC E15 LV showed the desirable changes in the dissolution profile by its hydrophilic nature since the colon is known for its less fluid content. The hydrophilic HPMC E15 LV allowed the colonic fluids to enter into the matrix and confirmed the drug release at the target site from a poorly water soluble polymer such as Chitosan and also from water soluble Pectin. The dramatic changes occurred in the drug release profile and physicochemical characteristics of the Pectin, Chitosan matrix tablets when a premium polymer HPMC E15 LV added in the formulation design in the optimized concentration. Various drug release mechanisms used for the examination of drug release characteristics. Drug release followed the combined mechanism of diffusion, erosion, swelling and polymer entanglement. In recent decade, IBD attracts many patents in novel treatment methods by using novel drug delivery systems. PMID:24597626

Newton, A M J; Lakshmanan, Prabakaran

2014-04-01

38

Chitosan microspheres in novel drug delivery systems.  

PubMed

The main aim in the drug therapy of any disease is to attain the desired therapeutic concentration of the drug in plasma or at the site of action and maintain it for the entire duration of treatment. A drug on being used in conventional dosage forms leads to unavoidable fluctuations in the drug concentration leading to under medication or overmedication and increased frequency of dose administration as well as poor patient compliance. To minimize drug degradation and loss, to prevent harmful side effects and to increase drug bioavailability various drug delivery and drug targeting systems are currently under development. Handling the treatment of severe disease conditions has necessitated the development of innovative ideas to modify drug delivery techniques. Drug targeting means delivery of the drug-loaded system to the site of interest. Drug carrier systems include polymers, micelles, microcapsules, liposomes and lipoproteins to name some. Different polymer carriers exert different effects on drug delivery. Synthetic polymers are usually non-biocompatible, non-biodegradable and expensive. Natural polymers such as chitin and chitosan are devoid of such problems. Chitosan comes from the deacetylation of chitin, a natural biopolymer originating from crustacean shells. Chitosan is a biocompatible, biodegradable, and nontoxic natural polymer with excellent film-forming ability. Being of cationic character, chitosan is able to react with polyanions giving rise to polyelectrolyte complexes. Hence chitosan has become a promising natural polymer for the preparation of microspheres/nanospheres and microcapsules. The techniques employed to microencapsulate with chitosan include ionotropic gelation, spray drying, emulsion phase separation, simple and complex coacervation. This review focuses on the preparation, characterization of chitosan microspheres and their role in novel drug delivery systems. PMID:22707817

Mitra, Analava; Dey, Baishakhi

2011-07-01

39

Chitosan Microspheres in Novel Drug Delivery Systems  

PubMed Central

The main aim in the drug therapy of any disease is to attain the desired therapeutic concentration of the drug in plasma or at the site of action and maintain it for the entire duration of treatment. A drug on being used in conventional dosage forms leads to unavoidable fluctuations in the drug concentration leading to under medication or overmedication and increased frequency of dose administration as well as poor patient compliance. To minimize drug degradation and loss, to prevent harmful side effects and to increase drug bioavailability various drug delivery and drug targeting systems are currently under development. Handling the treatment of severe disease conditions has necessitated the development of innovative ideas to modify drug delivery techniques. Drug targeting means delivery of the drug-loaded system to the site of interest. Drug carrier systems include polymers, micelles, microcapsules, liposomes and lipoproteins to name some. Different polymer carriers exert different effects on drug delivery. Synthetic polymers are usually non-biocompatible, non-biodegradable and expensive. Natural polymers such as chitin and chitosan are devoid of such problems. Chitosan comes from the deacetylation of chitin, a natural biopolymer originating from crustacean shells. Chitosan is a biocompatible, biodegradable, and nontoxic natural polymer with excellent film-forming ability. Being of cationic character, chitosan is able to react with polyanions giving rise to polyelectrolyte complexes. Hence chitosan has become a promising natural polymer for the preparation of microspheres/nanospheres and microcapsules. The techniques employed to microencapsulate with chitosan include ionotropic gelation, spray drying, emulsion phase separation, simple and complex coacervation. This review focuses on the preparation, characterization of chitosan microspheres and their role in novel drug delivery systems. PMID:22707817

Mitra, Analava; Dey, Baishakhi

2011-01-01

40

Tannin-chitosan composites  

US Patent & Trademark Office Database

The invention provides a composition comprising a matrix of chitosan and a tannin wherein the chitosan is electrostatically bonded to the tannin to form a chitosan-tannin composite material. The chitosan can be partially or fully deacetylated, and the tannin can be a monomeric or an oligomeric proanthocyanidin or a hydrolysable tannin. The chitosan-tannin composite material can be a nanoparticle, a hydrogel film, a bio-foam, or a biogel, or the chitosan-tannin composite material can coat a liposome. The composite materials can be used for drug delivery, for antibacterial and/or antifungal applications, for tissue engineering applications, for wound healing applications, or they can be used as adjuvants for vaccination, including oral vaccinations. The invention also provides methods of preparing the composite materials and their various forms.

2014-02-04

41

Chitosan against cutaneous pathogens.  

PubMed

Propionibacterium acnes and Staphylococcus aureus are cutaneous pathogens that have become increasingly resistant to antibiotics. We sought to determine if chitosan, a polymer of deacetylated chitin, could be used as a potential treatment against these bacteria. We found that higher molecular weight chitosan had superior antimicrobial properties compared to lower molecular weights, and that this activity occurred in a pH dependent manner. Electron and fluorescence microscopy revealed that chitosan forms aggregates and binds to the surface of bacteria, causing shrinkage of the bacterial membrane from the cell wall. Of special relevance, clinical isolates of P. acnes were vulnerable to chitosan, which could be combined with benzoyl peroxide for additive antibacterial effect. Chitosan also demonstrated significantly less cytotoxicity to monocytes than benzoyl peroxide. Overall, chitosan demonstrates many promising qualities for treatment of cutaneous pathogens. PMID:23829873

Champer, Jackson; Patel, Julie; Fernando, Nathalie; Salehi, Elaheh; Wong, Victoria; Kim, Jenny

2013-01-01

42

Preparation of chitosan gel  

NASA Astrophysics Data System (ADS)

Aerogel conditioning of the chitosan makes it possible to prepare porous solids of significant specific surface. The increase in the chitosan concentration or the degree of acetylation decreases the specific surface of the synthesized chitosan gel. Whereas drying with supercritical CO2 more effectively makes it possible to preserve the volume of the spheres of gel and to have a more significant specific surface in comparison with evaporative drying.

Moussaoui, Y.; Mnasri, N.; Elaloui, E.; Ben Salem, R.; Lagerge, S.; de Menorval, L. C.

2012-06-01

43

Chitosan derivatives with antimicrobial, antitumour and antioxidant activities--a review.  

PubMed

Chitosan is a linear polysaccharide with a good biodegradability, biocompatibility, and no toxicity, which provide it with huge potential for future development. The chitosan molecule appears to be a suitable polymeric complex for many biomedical applications. This review gathers current findings on the antibacterial, antifungal, antitumour and antioxidant activities of chitosan derivatives and concurs with our previous review presenting data collected up to 2008. Antibacterial activity is based on molecular weight, the degree of deacetylation, the type of substitutents, which can be cationic or easily form cations, and the type of bacterium. In general, high molecular weight chitosan cannot pass through cell membranes and forms a film that protects cells against nutrient transport through the microbial cell membrane. Low molecular weight chitosan derivatives are water soluble and can better incorporate the active molecule into the cell. Gram-negative bacteria, often represented by Escherichia coli, have an anionic bacterial surface on which cationic chitosan derivatives interact electrostatically. Thus, many chitosan conjugates have cationic components such as ammonium, pyridinium or piperazinium substituents introduced into their molecules to increase their positive charge. Gram-positive bacteria like Staphylococcus aureus are inhibited by the binding of lower molecular weight chitosan derivatives to DNA or RNA. Chitosan nanoparticles exhibit an increase in loading capacity and efficacy. Antitumour active compounds such as doxorubicin, paclitaxel, docetaxel and norcantharidin are used as drug carriers. It is evident that chitosan, with its low molecular weight, is a useful carrier for molecular drugs requiring targeted delivery. The antioxidant scavenging activity of chitosan has been established by the strong hydrogen-donating ability of chitosan. The low molecular weight and greater degree of quarternization have a positive influence on the antioxidant activity of chitosan. Phenolic and polyphenolic compounds with antioxidant effects are condensed with chitosan to form mutual prodrugs. PMID:22074429

Jarmila, Vinsová; Vavríková, Eva

2011-01-01

44

Assessment of Chitosan-Affected Metabolic Response by Peroxisome Proliferator-Activated Receptor Bioluminescent Imaging-Guided Transcriptomic Analysis  

PubMed Central

Chitosan has been widely used in food industry as a weight-loss aid and a cholesterol-lowering agent. Previous studies have shown that chitosan affects metabolic responses and contributes to anti-diabetic, hypocholesteremic, and blood glucose-lowering effects; however, the in vivo targeting sites and mechanisms of chitosan remain to be clarified. In this study, we constructed transgenic mice, which carried the luciferase genes driven by peroxisome proliferator-activated receptor (PPAR), a key regulator of fatty acid and glucose metabolism. Bioluminescent imaging of PPAR transgenic mice was applied to report the organs that chitosan acted on, and gene expression profiles of chitosan-targeted organs were further analyzed to elucidate the mechanisms of chitosan. Bioluminescent imaging showed that constitutive PPAR activities were detected in brain and gastrointestinal tract. Administration of chitosan significantly activated the PPAR activities in brain and stomach. Microarray analysis of brain and stomach showed that several pathways involved in lipid and glucose metabolism were regulated by chitosan. Moreover, the expression levels of metabolism-associated genes like apolipoprotein B (apoB) and ghrelin genes were down-regulated by chitosan. In conclusion, these findings suggested the feasibility of PPAR bioluminescent imaging-guided transcriptomic analysis on the evaluation of chitosan-affected metabolic responses in vivo. Moreover, we newly identified that downregulated expression of apoB and ghrelin genes were novel mechanisms for chitosan-affected metabolic responses in vivo. PMID:22496881

Kao, Chia-Hung; Hsiang, Chien-Yun; Ho, Tin-Yun

2012-01-01

45

Synthesis and Ultraviolet Visible Spectroscopy Studies of Chitosan Capped Gold Nanoparticles and Their Reactions with Analytes  

PubMed Central

Gold nanoparticles (AuNPs) had been synthesized with various molarities and weights of reducing agent, monosodium glutamate (MSG), and stabilizer chitosan, respectively. The significance of chitosan as stabilizer was distinguished through transmission electron microscopy (TEM) images and UV-Vis absorption spectra in which the interparticles distance increases whilst retaining the surface plasmon resonance (SPR) characteristics peak. The most stable AuNPs occurred for composition with the lowest (1?g) weight of chitosan. AuNPs capped with chitosan size stayed small after 1 month aging compared to bare AuNPs. The ability of chitosan capped AuNPs to uptake analyte was studied by employing amorphous carbon nanotubes (?-CNT), copper oxide (Cu2O), and zinc sulphate (ZnSO4) as the target material. The absorption spectra showed dramatic intensity increased and red shifted once the analyte was added to the chitosan capped AuNPs. PMID:25215315

Mohd Sultan, Norfazila

2014-01-01

46

Chitosan-transition metal ions complexes for selective arsenic(V) preconcentration.  

PubMed

Chitosan is naturally occurring bio-polymer having strong affinity towards transition metal ions. Chitosan complexed with transition metal ions takes up inorganic arsenic anions from aqueous medium. In present work, As(V) sorption in the chitosan complexed with different metal ions like Cu(II), Fe(III), La(III), Mo(VI) and Zr(IV) were studied. Sorptions of As(V) in CuS embedded chitosan, (3-aminopropyl) triethoxysilane (APTS) embedded chitosan, epichlorohydrin (ECH) crosslinked chitosan and pristine chitosan were also studied. (74)As radiotracer was prepared specifically for As(V) sorption studies by irradiation of natural germanium target with 18 MeV proton beam. The sorption studies indicated that Fe(III) and La(III) complexed with chitosan sorbed 95 ± 2% As(V) from aqueous samples in the pH range of 3-9. However, Fe(III)-chitosan showed better sorption efficiency (91 ± 2%) for As(V) from seawater than La(III)-chitosan (80 ± 2%). Therefore, Fe(III)-chitosan was selected to prepare the self-supported membrane and poly(propylene) fibrous matrix supported sorbent. The experimental As(V) sorption capacities of the fibrous and self-supported Fe(III)-chitosan sorbents were found to be 51 and 109 mg g(-1), respectively. These materials were characterized by XRD, SEM and EDXRF, and used for preconcentration of As(V) in aqueous media like tap water, ground water and seawater. To quantify the As(V) preconcentrated in Fe(III)-chitosan, the samples were subjected to instrumental neutron activation analysis (INAA) using reactor neutrons. As(V) separations were carried out using a two compartments permeation cell for the self-supported membrane and flow cell using the fibrous sorbent. The total preconcentration of arsenic content was also explored by converting As(III) to As(V). PMID:23622983

Shinde, Rakesh N; Pandey, A K; Acharya, R; Guin, R; Das, S K; Rajurkar, N S; Pujari, P K

2013-06-15

47

A pH-sensitive gene delivery system based on folic acid-PEG-chitosan - PAMAM-plasmid DNA complexes for cancer cell targeting.  

PubMed

In this study, pH-sensitive biomaterials coated polymer/DNA nanocomplexes containing a high mobility group box 1 (HMGB1) were developed as an efficient non-viral gene delivery system. HMGB1 is a family of endogenous molecules that contains nuclear locating sequences (NSL). Polyethylene glycol tethered carboxylated chitosan modified with folic acid (FA-PEG-CCTS) was synthesized and its buffering capacity was determined by acid-base titration. A pH-sensitive core-shell system FA-PEG-CCTS/PAMAM/HMGB1/pDNA nanocomplexes (FPCPHDs), was prepared and characterized. Electrophoresis showed that FPCPHDs were resistant to heparin replacement and DNase I digestion. FPCPHDs exhibited only minor toxic effects on HepG2 and KB cells. The results of both luciferase activity assay and RFP fluorescence intensity analysis showed that FPCPHDs enhanced gene transfection and expression in KB cells. Moreover, gene transfection and expression in KB cells were inhibited by free folic acid. Intracellular trafficking of FPCPHDs in KB cells showed that FPCPHDs could rapidly escape from endo-lysosomes and become exclusively located in the nucleus at 3 h post transfection. In addition, FPCPHDs exhibited increased red fluorescence protein (RFP) expression at the tumor site of S180 xenograft nude mice. All results suggest that FPCPHDs is an efficient approach to improve the transfection and expression efficiency in most FR-positive cancer cells. PMID:24094823

Wang, Mingyue; Hu, Haiyang; Sun, Yuqi; Qiu, Lipeng; Zhang, Jie; Guan, Guannan; Zhao, Xiuli; Qiao, Mingxi; Cheng, Liang; Cheng, Lifang; Chen, Dawei

2013-12-01

48

Enzymatic degradation of thiolated chitosan.  

PubMed

The objective of this study was to evaluate the biodegradability of thiolated chitosans in comparison to unmodified chitosan. Mediated by carbodiimide, thioglycolic acid (TGA) and mercaptonicotinic acid (MNA) were covalently attached to chitosan via formation an amide bond. Applying two different concentrations of carbodiimide 50 and 100?mM, two chitosan TGA conjugates (TGA A and TGA B) were obtained. According to chitosan solution (3% m/v) thiomer solutions were prepared and chitosanolytic enzyme solutions were added. Lysozyme, pectinase and cellulase were examined in chitosan degrading activity. The enzymatic degradability of these thiomers was investigated by viscosity measurements with a plate-plate viscometer. The obtained chitosan TGA conjugate A displayed 267.7 µmol and conjugate B displayed 116.3 µmol of immobilized thiol groups. With 325.4 µmol immobilized thiol groups, chitosan MNA conjugate displayed the most content of thiol groups. In rheological studies subsequently the modification proved that chitosan TGA conjugates with a higher coupling rate of thiol groups were not only degraded to a lesser extent by 20.9-26.4% but also more slowly. Chitosan mercaptonicotinic acid was degraded by 31.4-50.1% depending the investigated enzyme and even faster than unmodified chitosan. According to these results the biodegradability can be influenced by various modifications of the polymer which showed in particular that the rate of biodegradation is increased when MNA is the ligand, whereas the degradation is hampered when TGA is used as ligand for chitosan. PMID:23057506

Laffleur, Flavia; Hintzen, Fabian; Rahmat, Deni; Shahnaz, Gul; Millotti, Gioconda; Bernkop-Schnürch, Andreas

2013-10-01

49

Chitosan hollow fiber membranes.  

PubMed

Chitosan hollow fibers were produced by wet spinning, taking advantage of the unique rheological properties of highly viscous chitosan solutions in acetic acid. The mechanical and separation properties of hollow fibers were tested. The mechanical properties were determined by measuring tensile force, tensile stress, elongation, and initial elasticity module. The separation properties were specified by determining retention coefficients of particular blood components and determining cut-off of the membrane by the analysis of dextran molecular weight distribution in the feed and permeate using a technique of gel chromatography (GPC)-Shimadzu gel chromatograph. PMID:14691939

Modrzejewska, Zofia; Eckstein, Wojciech

2004-01-01

50

Analgesis and wound healing effect of chitosan and carboxymethyl chitosan on scalded rats  

NASA Astrophysics Data System (ADS)

Analgesis and wound healing effect of chitosan and carboxymethyl chitosan on scalded rats were investigated. A II degree scald model was established in rats, which was subsequently treated with chitosan and carboxymethyl chitosan solution, respectively. The concentration of bradykinin and 5-hydroxytryptophan was detected by assaying enzyme-linked immunosorbent. Healing condition was observed and pathological sections were made to determine the healing effect of chitosan and carboxymethyl chitosan. Results showed that the concentration of bradykinin and 5-hydroxytryptophan peaked at the third hour post-wound in all groups, while the concentration of hydroxyproline peaked at the seventh day post-wound in both chitosan and carboxymethyl chitosan group. The concentration of bradykinin and 5-hydroxytryptophan of carboxymethyl chitosan group was significantly lower than that of control ( P < 0.05), while that of chitosan group was similar to that of control ( P > 0.05). These findings indicated that carboxymethyl chitosan reduced the concentration of algogenic substances, resulting in analgesia. During the whole recovery process, the hydroxyproline concentration in chitosan and carboxymethyl chitosan group on day 3 and 7 was significantly higher than that of control ( P < 0.01); however the significance of such a highness decreased on day 14 ( P < 0.05). These findings indicated that chitosan and carboxymethyl chitosan accelerated tissue repair. Meanwhile, chitosan performed better in healing than carboxymethyl chitosan in both decrustation and healing time. In conclusion, carboxymethyl chitosan showed significant analgesis and wound-healing promotion effect, but chitosan only showed wound-healing promotion effect.

Huang, Shuya; Han, Baoqin; Shao, Kai; Yu, Miao; Liu, Wanshun

2014-10-01

51

Acid hydrolysis of chitosans  

Microsoft Academic Search

The hydrolysis of the O-glycosidic linkages (depolymerization) and the N-acetyl linkage (de-N-acetylation) of partially N-acetylated chitosans were studied in dilute and concentrated HCl. The rate of hydrolysis of the glycosidic linkages was found to be equal to the rate of de-N-acetylation in dilute acid, while the glycosidic linkages was hydrolysed more than 10 times faster than the N-acetyl linkage in

K. M. Vårum; M. H. Ottøy; O. Smidsrød

2001-01-01

52

Enzyme encapsulation on chitosan microbeads  

Microsoft Academic Search

The influence of two variables (cross-linking and protein concentration) on the activity shown by ?-amylase and invertase immobilized on chitosan microbeads was studied by means of full factorial experimental designs. Microencapsulation on chitosan beads has shown to be an effective immobilization method for both enzymes and observed differences in their behaviour are explained mainly by the molecular weight of their

M. I. González Siso; E. Lang; B. Carrenõ-Gómez; M. Becerra; F. Otero Espinar; J. Blanco Méndez

1997-01-01

53

Analysis of a change in bacterial community in different environments with addition of chitin or chitosan  

Microsoft Academic Search

The temporal changes of a bacterial community in soil with chitin or chitosan added were analyzed by PCR-denaturing gradient gel electrophoresis (DGGE) targeting the 16S rRNA gene using total DNAs prepared from the community. Band patterns of PCR-DGGE confirmed that 31 species become predominant after the addition of chitin or chitosan. The determination of the nucleotide sequences of the bands

Kazuaki Sato; Yasuhito Azama; Masahiro Nogawa; Goro Taguchi; Makoto Shimosaka

2010-01-01

54

Comparison of VEGF gene silencing efficiencies of chitosan and protamine complexes containing shRNA.  

PubMed

VEGF is an angiogenic factor promoting the proliferation and migration of endothelial cells. Inhibition of VEGF by RNAi mechanism is one of the novel and the most important strategies in antiangiogenesis therapy. In this study, the tumor silencing efficiency of ternary complexes after addition of protamine to chitosan complexes containing VEGF targeting shRNA was investigated. Besides chitosan, protamine is an effective gene delivery material. Binary and ternary complexes consisting of chitosan, protamine, and shRNA were prepared to target VEGF, their morphology, size, and zeta potential of the complexes being measured. The average size of the complexes was between 173 and 284?nm and zeta potential was between +10 and 16?mV. In the ternary complexes, size decreased as the chitosan ratio increased; however, its molecular weight had no effect on the size of complexes. HeLa, HEK293, and MCF-7 cell lines were used for in vitro transfection. VEGF was assayed by ELISA. A higher silencing effect was obtained using ternary complexes. Transgene expression was increased by adding protamine to chitosan complexes. Gene inhibition values in cell lines followed the rank HEK293>HeLa>MCF-7. The addition of protamine to the chitosan/shRNA (VEGF) complexes increased the knockdown of VEGF genes in the cell lines, and no cytotoxicity was found after the complexes had been incorporated into the cells. PMID:24890139

Erdem-Çakmak, Fulden; Ozba?-Turan, Suna; Salva, Emine; Akbu?a, Jülide

2014-11-01

55

Immobilization of catalase on chitosan film  

Microsoft Academic Search

Catalase was immobilized on the chitosan film that is a natural polymer. Studies were done on free catalase and immobilized catalase on chitosan film concerning the determination of optimum temperature, optimum pH, thermal stability, storage stability, operational stability, and kinetic parameters. It was determined that optimum temperature for free catalase and immobilized catalase on chitosan film is 25°C, and optimum

?enay Akku? Çetinus; H. Nursevin Öztop

2000-01-01

56

Versatile carboxymethyl chitin and chitosan nanomaterials: a review.  

PubMed

Biocompatibility, biodegradability, and low cost of chitin and chitosan have drawn immense attention in many fields including medicine, bioinspired material science, pharmaceuticals, and agriculture. Their handling and processing are difficult owing to its insolubility in neutral aqueous solution or organic solvents. One of the methods used to improve the solubility characteristics of chitin and chitosan is chemical modification. Introducing a carboxymethyl group is the most advantageous method of increasing the solubility of chitosan at neutral and alkaline pH. Carboxymethyl chitin (CMC) and carboxymethyl chitosan (CMCS) are water soluble derivatives formed by introducing CH?COOH function into the polymer which endows it with better biological properties. The functional group makes CMC/CMCS nanoparticles (NPs) efficient vehicles for the delivery of DNA, proteins, and drugs. This review provides an overview of the characteristics of CMC/CMCS NPs as well as fulfills the task of describing and discussing its important roles primarily in cancer nanomedicine detailing the targeted drug delivery aspect. The application of these NPs in imaging, agriculture, and textiles has also been highlighted. The review also elaborates the advantages of using the CMC and CMCS NPs for drug and gene delivery. PMID:25266740

Narayanan, Deepa; Jayakumar, R; Chennazhi, K P

2014-01-01

57

[Chitosan-siRNA complex nanoparticles for gene silencing].  

PubMed

Small interference RNA (siRNA) induced RNA interference (RNAi) technology has shown high specificity and high efficiency of silencing target gene expression, and it is becoming a promising candidate drug for the therapy of cancer and viral infection diseases. At present, the lack of safe and effective carrier materials and delivery systems of siRNA through extracellular and intracellular barriers still hampers the clinical application. In order to overcome this difficulty, we proposed using chitosan, naturally occurring polycation, to form complex siRNA against green fluorescence protein (siRNA-eGFP). The spherical and stable chitosan-siRNA nanoparticles with 83%-94% siRNA complex efficiency can be formulated under mild electrostatic interaction. The size and Zeta potential of nanoparticles were within the range of 90-180 nm and 10-30 mV, respectively. 80% cell viability could be maintained inthe course of incubating with chitosan-siRNA nanoparticles. Moreover, nearly 80% gene silencing efficiency of chitosan-siRNA nanoparticles was realized. PMID:20337033

Liu, Xiudong

2010-02-01

58

Preparation of chitosan filament applying new coagulation system  

Microsoft Academic Search

A new coagulation system for chitosan, aqueous alcohol solution of calcium chloride or acetate, was found and successfully applied for spinning of chitosan filament. FT-IR and atomic absorption spectrophotometric experiments indicated that chitosan coagulation was induced through calcium chelation with amino group of chitosan molecule. The original spun filament was soluble in water because chitosan exists as an acetic acid

Hiroshi Tamura; Yukihiko Tsuruta; Kouki Itoyama; Wannasiri Worakitkanchanakul; Ratana Rujiravanit; Seiichi Tokura

2004-01-01

59

Chitosan–starch composite film: preparation and characterization  

Microsoft Academic Search

Chitosan film has potential applications in agriculture, food, and pharmacy. However, films made only from chitosan lack water resistance and have poor mechanical properties. Forming miscible, biodegradable composite film from chitosan with other hydrophilic biopolymers is an alternative. The objective of this study was to prepare chitosan\\/starch composite films by combining chitosan (deacetylated degree, 90%) solution and two thermally gelatinized

Y. X. Xu; K. M. Kim; M. A. Hanna; D. Nag

2005-01-01

60

Effects of Chitosan Concentration and Precipitation Bath Concentration on the Material Properties of Porous Crosslinked Chitosan Beads  

Microsoft Academic Search

Flaked chitosan obtained by deacetylating 80% of chitin extracted from crab shell was dissolved in acetic acid aqueous solution, and highly porous chitosan beads were formed by dropping the chitosan solution into aqueous NaOH solution, followed by crosslinking with ethylene glycol diglycidyl ether. Fifteen different crosslinked chitosan beads (CRCS) were fabricated by controlling the concentration Cchitosan of chitosan in the

Yoshihide Kawamura; Hiroyuki Yoshida; Satoru Asai; Ituo Kurahashi; Hiroaki Tanibe

1997-01-01

61

Antimicrobial activity of hydroxylbenzenesulfonailides derivatives of chitosan, chitosan sulfates and carboxymethyl chitosan.  

PubMed

Chitosan, carboxymethyl chitosan (CMCS) and chitosan sulfates (CSS) with different molecular weight were modified by reacting with 4-hydroxyl-5-chloride-1,3-benzene-disulfo-chloride or 2-hydroxyl-5-chloride-1,3-benzene-disulfo-chloride to give 12 kinds of new hydroxylbenzenesulfonailides derivatives of them. The preparation conditions of the derivatives were discussed in this paper, and their structures were characterized by FT-IR and 13C NMR spectroscopy. The solubility of the derivatives was measured in the experiment. In addition, their antimicrobial activities against four bacteria and five crop-threatening pathogenic fungi were tested in the experiment. Besides, the rule and mechanism of their antibacterial activities were discussed in this paper. PMID:19414029

Zhong, Zhimei; Li, Pengcheng; Xing, Ronge; Liu, Song

2009-08-01

62

Chitin, Chitosan, and Glycated Chitosan Regulate Immune Responses: The Novel Adjuvants for Cancer Vaccine  

PubMed Central

With the development of cancer immunotherapy, cancer vaccine has become a novel modality for cancer treatment, and the important role of adjuvant has been realized recently. Chitin, chitosan, and their derivatives have shown their advantages as adjuvants for cancer vaccine. In this paper, the adjuvant properties of chitin and chitosan were discussed, and some detailed information about glycated chitosan and chitosan nanoparticles was also presented to illustrate the trend for future development. PMID:23533454

Li, Xiaosong; Min, Min; Du, Nan; Gu, Ying; Hode, Tomas; Naylor, Mark; Chen, Dianjun; Nordquist, Robert E.; Chen, Wei R.

2013-01-01

63

Chitosan and depolymerized chitosan oligomers as condensing carriers for in vivo plasmid delivery  

Microsoft Academic Search

Chitosan is a polysaccharide that demonstrates much potential as a gene delivery system. The ability of a commercially available chitosan and depolymerized chitosan oligomers to condense plasmid was determined using TEM and microtitration calorimetry, while the diameter and stability of the resultant complexes were measured using laser light scattering. Selected complexes were physically stable to challenge with both serum and

Fiona C MacLaughlin; Russell J Mumper; Jijun Wang; Jenna M Tagliaferri; Inder Gill; Mike Hinchcliffe; Alain P Rolland

1998-01-01

64

Chitosan Modification and Pharmaceutical/Biomedical Applications  

PubMed Central

Chitosan has received much attention as a functional biopolymer for diverse applications, especially in pharmaceutics and medicine. Our recent efforts focused on the chemical and biological modification of chitosan in order to increase its solubility in aqueous solutions and absorbability in the in vivo system, thus for a better use of chitosan. This review summarizes chitosan modification and its pharmaceutical/biomedical applications based on our achievements as well as the domestic and overseas developments: (1) enzymatic preparation of low molecular weight chitosans/chitooligosaccharides with their hypocholesterolemic and immuno-modulating effects; (2) the effects of chitin, chitosan and their derivatives on blood hemostasis; and (3) synthesis of a non-toxic ion ligand—D-Glucosaminic acid from Oxidation of D-Glucosamine for cancer and diabetes therapy. PMID:20714418

Zhang, Jiali; Xia, Wenshui; Liu, Ping; Cheng, Qinyuan; Tahirou, Talba; Gu, Wenxiu; Li, Bo

2010-01-01

65

Flocculation of river silt using chitosan  

Microsoft Academic Search

Flocculation of silt in river water using chitosan was studied in the pH range 4–9, and suspended solid concentrations in the range 20–80mg\\/L. Chitosan effectively reduces turbidity due to silt by flocculation and settling. Flocculation efficiency is very sensitive to pH, and reaches a maximum at pH 7. The optimal chitosan concentration required to effect flocculation is 0.5mg\\/L and is

Ravi Divakaran; V. N. Sivasankara Pillai

2002-01-01

66

New chitosan nanobubbles for ultrasound-mediated gene delivery: preparation and in vitro characterization  

PubMed Central

Background The development of nonviral gene delivery systems is one of the most intriguing topics in nanomedicine. However, despite the advances made in recent years, several key issues remain unsettled. One of the main problems relates to the difficulty in designing nanodevices for targeted delivery of genes and other drugs to specific anatomic sites. In this study, we describe the development of a novel chitosan nanobubble-based gene delivery system for ultrasound-triggered release. Methods and results Chitosan was selected for the nanobubble shell because of its low toxicity, low immunogenicity, and excellent biocompatibility, while the core consisted of perfluoropentane. DNA-loaded chitosan nanobubbles were formed with a mean diameter of less than 300 nm and a positive surface charge. Transmission electron microscopic analysis confirmed composition of the core-shell structure. The ability of the chitosan nanobubbles to complex with and protect DNA was confirmed by agarose gel assay. Chitosan nanobubbles were found to be stable following insonation (2.5 MHz) for up to 3 minutes at 37°C. DNA release was evaluated in vitro in both the presence and absence of ultrasound. The release of chitosan nanobubble-bound plasmid DNA occurred after just one minute of insonation. In vitro transfection experiments were performed by exposing adherent COS7 cells to ultrasound in the presence of different concentrations of plasmid DNA-loaded nanobubbles. In the absence of ultrasound, nanobubbles failed to trigger transfection at all concentrations tested. In contrast, 30 seconds of ultrasound promoted a moderate degree of transfection. Cell viability experiments demonstrated that neither ultrasound nor the nanobubbles affected cell viability under these experimental conditions. Conclusion Based on these results, chitosan nanobubbles have the potential to be promising tools for ultrasound-mediated DNA delivery. PMID:22802689

Cavalli, Roberta; Bisazza, Agnese; Trotta, Michele; Argenziano, Monica; Civra, Andrea; Donalisio, Manuela; Lembo, David

2012-01-01

67

Fragmentation of Chitosan by Acids  

PubMed Central

Fragmentation of chitosan in aqueous solution by hydrochloric acid was investigated. The kinetics of fragmentation, the number of chain scissions, and polydispersity of the fragments were followed by viscometry and size exclusion chromatography. The chemical structure and the degree of N-acetylation (DA) of the original chitosan and its fragments were examined by 1H NMR spectroscopy and elemental analysis. The kinetic data indicates that the reaction was of first order. The results of polydispersity and the DA suggest that the selected experimental conditions (temperature and concentration of acid) were appropriate to obtain the fragments having the polydispersity and the DA similar to or slightly different from those of the original one. A procedure to estimate molecular weight of fragments as well as the number of chain scissions of the fragments under the experimental conditions was also proposed. PMID:24302858

Arul, Joseph; Charlet, Gerard

2013-01-01

68

Analysis of a change in bacterial community in different environments with addition of chitin or chitosan.  

PubMed

The temporal changes of a bacterial community in soil with chitin or chitosan added were analyzed by PCR-denaturing gradient gel electrophoresis (DGGE) targeting the 16S rRNA gene using total DNAs prepared from the community. Band patterns of PCR-DGGE confirmed that 31 species become predominant after the addition of chitin or chitosan. The determination of the nucleotide sequences of the bands of the 31 species indicated that 20 species belonged to the division Proteobacteria, and that the genus Cellvibrio was apparently predominant among them (7/20). The 16S rRNA sequences of the 16 deduced species (16/31) showed less than 98% similarities to those of previously identified bacteria, indicating that the species were derived from unidentified bacteria. The total community DNAs extracted from bacterial cells adsorbed on the surface of flakes of chitin and chitosan placed in a river, a moat, or soil were subjected to PCR-DGGE to examine the extent of diversity of chitinolytic bacteria among different environments. The predominant species significantly differed between the chitin and chitosan placed in the river and moat, but not so much between those placed in the soil. The large difference between the diversities of the three bacterial communities indicated that a wide variety of bacteria including unidentified ones are involved in the degradation of chitin and chitosan in the above-mentioned natural environments. PMID:20347770

Sato, Kazuaki; Azama, Yasuhito; Nogawa, Masahiro; Taguchi, Goro; Shimosaka, Makoto

2010-05-01

69

Fully embeddable chitosan microneedles as a sustained release depot for intradermal vaccination.  

PubMed

This study introduces a microneedle transdermal delivery system, composed of embeddable chitosan microneedles and a poly(L-lactide-co-D,L-lactide) (PLA) supporting array, for complete and sustained delivery of encapsulated antigens to the skin. Chitosan microneedles were mounted to the top of a strong PLA supporting array, providing mechanical strength to fully insert the microneedles into the skin. When inserted into rat skin in vivo, chitosan microneedles successfully separated from the supporting array and were left within the skin for sustained drug delivery without requiring a transdermal patch. The microneedle penetration depth was approximately 600 ?m (i.e. the total length of the microneedle), which is beneficial for targeted delivery of antigens to antigen-presenting cells in the epidermis and dermis. To evaluate the utility of chitosan microneedles for intradermal vaccination, ovalbumin (OVA; MW = 44.3 kDa) was used as a model antigen. When the OVA-loaded microneedles were embedded in rat skin in vivo, histological examination showed that the microneedles gradually degraded and prolonged OVA exposure at the insertion sites for up to 14 days. Compared to traditional intramuscular immunization, rats immunized by a single microneedle dose of OVA showed a significantly higher OVA-specific antibody response which lasted for at least 6 weeks. These results suggest that embeddable chitosan microneedles are a promising depot for extended delivery of encapsulated antigens to provide sustained immune stimulation and improve immunogenicity. PMID:23369214

Chen, Mei-Chin; Huang, Shih-Fang; Lai, Kuan-Ying; Ling, Ming-Hung

2013-04-01

70

Effect of chitosan multilayers encapsulation on controlled release performance of drug-loaded superparamagnetic alginate nanoparticles.  

PubMed

The near monodispersed ibuprofen-loaded superparamagnetic alginate (AL/IBU/Fe(3)O(4)) nanoparticles with particles size less than 200 nm were prepared via the facile heterogeneous coprecipitation of the superparamagnetic Fe(3)O(4) nanoparticles, sodium alginate (AL) and the model drug ibuprofen (IBU) from the aqueous dispersion. Then the chitosan multilayers were self-assembled onto the AL/IBU/Fe(3)O(4) nanoparticles to produce novel magnetic-targeted controlled release drug delivery system, with chitosan as the polycation (CS) and the carboxymethyl chitosan (CMCS) as the polyanion. The drug controlled releasing behaviors of the AL/IBU/Fe(3)O(4) nanoparticles and the CS multilayers encapsulated ibuprofen-loaded superparamagnetic alginate ((AL/IBU/Fe(3)O(4))@(CS-CMCS)(3)) nanoparticles were compared in the different pH media. In media with the same pH value, the encapsulated vessels exhibited the slower releasing rate. PMID:22052536

Lu, Chunyin; Liu, Peng

2012-02-01

71

Microencapsulated chitosan nanoparticles for lung protein delivery  

Microsoft Academic Search

It has already been demonstrated that spray drying is a very valuable technique for producing dry powders adequate for pulmonary delivery of drugs. We have developed chitosan\\/tripolyphosphate nanoparticles that promote peptide absorption across mucosal surfaces. The aim of this work was to microencapsulate protein-loaded chitosan nanoparticles using typical aerosol excipients, such as mannitol and lactose, producing microspheres as carriers of

Ana Grenha; Begoña Seijo; Carmen Remuñán-López

2005-01-01

72

Preparation of itraconazole-loaded liposomes coated by carboxymethyl chitosan and its pharmacokinetics and tissue distribution.  

PubMed

Liposomes are potential carriers for targeting and controlled drug delivery by the intravenous route. Carboxymethyl chitosan (CMC) is a ramification of chitosan with intrinsic water-solubility. The aim of this study is to prepare itraconazole-loaded liposomes coated by carboxymethyl chitosan (CMC-ITZ-Lips), to evaluate its physico-chemical characteristics and the tissue targeting after being injected intravenously (i.v.). This study uses a film dispersion method to prepare itraconazole-loaded liposomes (ITZ-Lips) prior to coating them with CMC. The concentrations of ITZ in selected organs were determined using reversed-phase high-performance liquid chromatography (HPLC) following i.v. administration of ITZ-Sol, ITZ-Lips, and CMC-ITZ-Lips. CMC-ITZ-Lips had an average diameter of 349.3?±?18?nm with a zeta potential of -35.71?±?0.62 mV and the in vitro antifungal activity was not inhibited by the entrapment. The CMC-ITZ-Lips exhibited a longer elimination half life (t(1/2?)) in vivo compared with ITZ-Sol and ITZ-Lips after i.v. injection to mice. The biodistribution in mice was also changed after ITZ was encapsulated in CMC coated liposomes. CMC-ITZ-Lips performed significant lung targeting efficiency with AUC, Te and Re of lung all showed obvious elevation. In this study itraconazole was successfully encapsulated into carboxymethyl chitosan-modified liposomes for application of injection. PMID:22111976

Wang, Jinping; Huang, Guihua

2011-11-01

73

The effect of chitosan concentration on the electrical property of chitosan-blended cellulose electroactive paper  

NASA Astrophysics Data System (ADS)

We studied the effect of chitosan blending on the electrical property of chitosan-blended cellulose electroactive paper (EAPap) under different humidity conditions. As the chitosan blending ratio increased, the real part of the dielectric constant of chitosan-blended cellulose EAPap increased while the dielectric loss factor decreased. From the curve fitting of the measured data using an electrode polarization model, it was found that increasing the chitosan ratio in the EAPap might promote a decrease in the relaxation time of the EAPap, resulting in an increase of the ion mobility and dc conductivity. Over 30% of the chitosan blending ratio, a gradual increment of the ion mobility of the EAPap was observed at 40% relative humidity, while a quadratic increment of the mobility was found at 60% relative humidity condition. This kind of ion-mobility-enhanced cellulose EAPap can be used not only for bending actuators but also for medical applications such as blood clotting patches.

Jang, Sang-Dong; Kim, Joo-Hyung; Zhijiang, Cai; Kim, Jaehwan

2009-01-01

74

Probing cellular behaviors through nanopatterned chitosan membranes  

NASA Astrophysics Data System (ADS)

This paper describes a high-throughput method for developing physically modified chitosan membranes to probe the cellular behavior of MDCK epithelial cells and HIG-82 fibroblasts adhered onto these modified membranes. To prepare chitosan membranes with micro/nanoscaled features, we have demonstrated an easy-to-handle, facile approach that could be easily integrated with IC-based manufacturing processes with mass production potential. These physically modified chitosan membranes were observed by scanning electron microscopy to gain a better understanding of chitosan membrane surface morphology. After MDCK cells and HIG-82 fibroblasts were cultured on these modified chitosan membranes for various culture durations (i.e. 1, 2, 4, 12 and 24 h), they were investigated to decipher cellular behavior. We found that both cells preferred to adhere onto a flat surface rather than on a nanopatterned surface. However, most (> 80%) of the MDCK cells showed rounded morphology and would suspend in the cultured medium instead of adhering onto the planar surface of negatively nanopatterned chitosan membranes. This means different cell types (e.g. fibroblasts versus epithelia) showed distinct capabilities/preferences of adherence for materials of varying surface roughness. We also showed that chitosan membranes could be re-used at least nine times without significant contamination and would provide us consistency for probing cell-material interactions by permitting reuse of the same substrate. We believe these results would provide us better insight into cellular behavior, specifically, microscopic properties and characteristics of cells grown under unique, nanopatterned cell-interface conditions.

Yang, Chung-Yao; Sung, Chun-Yen; Shuai, Hung-Hsun; Cheng, Chao-Min; Yeh, Andrew

2013-08-01

75

Herstellung von Chitosan und einige Anwendungen  

NASA Astrophysics Data System (ADS)

1. Die Deacetylierung von crabshell - Chitosan führte gleichzeitig zu einem drastischen Abfall der mittleren viscosimetrischen Molmasse ( Mv), insbesondere wenn die Temperatur und die Konzentration an NaOH erhöht werden. Diese Parameter beeinflussten jedoch nicht den Grad der Deacetylierung (DD). Wichtig ist jedoch die Quelle des Ausgangsmaterials: Chitin aus Pandalus borealis ist ein guter Rohstoff für die Herstellung von Chitosan mit niedrigem DD und gleichzeitig hoher mittlerer Mv, während Krill-Chitin (Euphausia superba) ein gutes Ausgangsmaterial zur Herstellung von Chitosan mit hohem DD und niedrigem Mv ist. Chitosan, das aus Insekten (Calliphora erythrocephala), unter milden Bedingungen (Temperatur: 100°C, NaOH-Konzentration: 40 %, Zeit: 1-2h ) hergestellt wurde, hatte die gleichen Eigenschaften hinsichtlich DD und Mv wie das aus Krill hergestellte Chitosan. Der Bedarf an Zeit, Energie und NaOH ist für die Herstellung von Insekten-Chitosan geringer als für crabshell-Chitosan vergleichbare Resultaten für DD und Mv. 2. Chitosan wurde durch den Schimmelpilz Aspergillus fumigatus zu Chitooligomeren fermentiert. Die Ausbeute beträgt 25%. Die Chitooligomere wurden mit Hilfe von HPLC und MALDI-TOF-Massenspektrmetrie identifiziert. Die Fermentationsmischung fördert die Immunität von Pflanzen gegen Bakterien und Virusinfektion. Die Zunahme der Immunität schwankt jedoch je nach System Pflanze-Pathogen. Die Fermentation von Chitosan durch Aspergillus fumigatus könnte eine schnelle und billige Methode zur Herstellung von Chitooligomeren mit guter Reinheit und Ausbeute sein. Eine partiell aufgereinigte Fermentationsmischung dieser Art könnte in der Landwirtschaft als Pathogeninhibitor genutzt werden. Durch kontrollierte Fermentation, die Chitooligomere in definierter Zusammensetzung (d.h. definierter Verteilung des Depolymerisationsgrades) liefert, könnte man zu Mischungen kommen, die für die jeweilige Anwendung eine optimale Bioaktivität besitzen. 3. Die aus Chitosan-Dispersionen hergestellten MCChB-Filme weisen bessere mechanische Eigenschaften (Bruchfestigkeit, Dehnung) und eine höhere Wasseraufnahmefähigkeit auf als Filme, die nach herkömmlichen Methoden aus sauerer Lösung hergestellt werden. Die Einführung von Proteinen ändert die mechanischen Eigenschaften der MCChB-Filme abhängig von der Art, der Proteine sowie des DD und der Mv des eingesetzte Chitosan. Die Zugabe von Protein beschleunigt den biologischen Abbau der MCChB-Filme. Aus den untersuchten MCChB-Filmen mit Proteinzusatz können leichte, reißfeste und dennoch elastische Materialen hergestellt werden. 4. Mit Hilfe von MCChB-Dispersion kann Papier modifiziert werden. Dadurch werden die mechanischen Eigenschaften verbessert und die Wasseraufnahme wird verringert. Die Zugabe von Proteinen verringert das Wasseraufnahmevermögen noch weiter. Ein geringes Wasseraufnahmevermögen ist der bedeutendste Faktor bei der Papierherstellung. Auch Papier, das mit einem MCChB-Protein-Komplexe modifiziert wurde, zeigt gute mechanische Eigenschaften. 5. Wird Chitosan durch unmittelbare Einführung von MCChB auf Cellulose-Fasern aufgebracht, so erhält man eine netzartige Struktur, während durch Ausfällung aufgebrachtes Chitosan eine dünne Schicht auf den Cellulose-Fasern bildet. Die netzartige Struktur erleichtert die Bioabbaubarkeit, während die Schichtstruktur diese erschwert. 6. Die guten mechanischen Eigenschaften, die geringe Wasseraufnahmefähigkeit und die mit Cellulose vergleichbare Bioabbaubarkeit von Papier, das mit MCChB modifiziert wurde, lassen MCChB für die Veredlung von Papier nützlich erscheinen. 1. Deacetylation of the crustacean chitosan causes drastically decrease in the Mv with increasing reaction temperature and time as well as the concentration of sodium hydroxide. However, the DD are relatively less affected. Pandalus borealis is a good source for production of chitosan having high Mv and low DD, whereas chitosan of medium to low Mv can ideally be prepared using krill chitin. Insect chitosan is prepared under milder condition a

Struszczyk, Marcin Henryk

2001-05-01

76

Water soluble folate-chitosan nanogels crosslinked by genipin.  

PubMed

Folate-chitosan conjugates were prepared by a concurrent functionalization and crosslinking reaction with the natural crosslinker genipin. Genipin molecule was employed simultaneously as crosslinker agent and spacer molecule in order to allow the functionalization with folic acid for active tumor targeting. The reaction was carried out in reverse microemulsion which provided colloidal size and monodisperse particle size distribution. The water solubility of the obtained folate-genipin-chitosan nanogels was studied as function of the pH of the medium and all nanoparticles were totally dispersible at physiological pH. The enzymatic degradability of the nanogels in a lysozyme solution was evaluated at acidic and physiological pH. QELS analyses of the swelling behavior of the nanogels with the pH did not show a clear pH-sensitivity. However, the study on the loading and release capacity of 5-fluorouracil revealed an interesting pH-responsive behavior of the nanogels that makes them promising as nanodevices for targeted anticancer drug delivery. PMID:24299756

Pujana, Maite Arteche; Pérez-Álvarez, Leyre; Iturbe, L Carlos Cesteros; Katime, Issa

2014-01-30

77

Engineering Tenofovir Loaded Chitosan Nanoparticles  

PubMed Central

The objective of this study was to engineer a model anti-HIV microbicide (Tenofovir) loaded chitosan based nanoparticles (NPs). Box-Behnken design allowed to assess the influence of formulation variables on the size of NPs and drug encapsulation efficiency (EE%) that were analyzed by dynamic light scattering and UV spectroscopy, respectively. The effect of the NPs on vaginal epithelial cells and Lactobacillus crispatus viability and their mucoadhesion to porcine vaginal tissue were assessed by cytotoxicity assays and fluorimetry, respectively. In the optimal aqueous conditions, the EE% and NPs size was 5.83% and 207.97nm, respectively. With 50% (v/v) ethanol/water as alternative solvent, these two responses increased to 20% and 602 nm, respectively. Drug release from medium (281 nm) and large size (602 nm)-sized NPs fitted the Higuchi (r2=0.991) and first-order release (r2=0.999) models, respectively. These NPs were not cytotoxic to both the vaginal epithelial cell line and Lactobacillus for 48 hours. When the diameter of the NPs decreased from 900 nm to 188 nm, the mucoadhesion increased from 6% to 12%. However, the combinatorial effect of EE% × mucoadhesion for larger size NPs was the highest. Overall, large-size, microbicide loaded chitosan NPs appeared to be promising nanomedicines for the prevention of HIV transmission. PMID:21704704

Meng, Jianing; Sturgis, Timothy F.; Youan, Bi-Botti C.

2011-01-01

78

Effects of carboxymethyl chitosan on the blood system of rats  

SciTech Connect

Highlights: {yields} We report, for the first time, the safety of carboxymethyl chitosan in blood system. {yields} CM-Chitosan has no significant effects on coagulation function of rats. {yields} CM-Chitosan has no significant effects on anticoagulation performance of rats. {yields} CM-Chitosan has no significant effects on fibrinolytic function of rats. {yields} CM-Chitosan has no significant effects on hemorheology of rats. -- Abstract: Carboxymethyl chitosan (CM-chitosan), a derivative of chitosan, was extensively studied in the biomedical materials field for its beneficial biological properties of hemostasis and stimulation of healing. However, studies examining the safety of CM-chitosan in the blood system are lacking. In this study CM-chitosan was implanted into the abdominal cavity of rats to determine blood indexes at different times and to evaluate the effects of CM-chitosan on the blood system of rats. Coagulation function was reflected by thrombin time (TT), prothrombin time (PT), activated partial thromboplatin time (APTT), fibrinogen (FIB) and platelet factor 4 (PF4) indexes; anti-coagulation performance was assessed by the index of antithrombinIII (ATIII); fibrinolytic function was reflected by plasminogen (PLG) and fibrin degradation product (FDP) indexes; and blood viscosity (BV) and plasma viscosity (PV) indexes reflected hemorheology. Results showed that CM-chitosan has no significant effects on the blood system of rats, and provides experimental basis for CM-chitosan to be applied in the field of biomedical materials.

Fu, Dawei [College of Marine Life Sciences, Ocean University of China, Qingdao 266003 (China)] [College of Marine Life Sciences, Ocean University of China, Qingdao 266003 (China); Han, Baoqin, E-mail: baoqinh@ouc.edu.cn [College of Marine Life Sciences, Ocean University of China, Qingdao 266003 (China)] [College of Marine Life Sciences, Ocean University of China, Qingdao 266003 (China); Dong, Wen; Yang, Zhao; Lv, You; Liu, Wanshun [College of Marine Life Sciences, Ocean University of China, Qingdao 266003 (China)] [College of Marine Life Sciences, Ocean University of China, Qingdao 266003 (China)

2011-04-29

79

Application of Chitosan in Remediation of Dyes  

Microsoft Academic Search

\\u000a Chitosan is derived from Chitin, which is the exoskeleton of a crab or shrimp shell and some other crustaceans. This project\\u000a explores this characteristic behavior of chitosan in the removal of dye from solution as a model for the potential application\\u000a in textile industry wastewater treatment. Azure dye was used as the model dye used in the textile industry wastewater

Gbekeloluwa B. Oguntimein; Olatunde Animashaun; Ivie Okpere

80

Facile synthesis of acyl chitosan isothiocyanates and their application to porphyrin-appended chitosan derivative.  

PubMed

Chitosan (1) was reacted with phenylisothiocyanate in 5% AcOH/H2O to give N-phenylthiocarbamoyl chitosan (2) with a degree of substitution (DS) of N-phenylthiocarbamoyl groups of 0.86 in 87.1% yield. The following acylation of compound 2 with hexanoyl chloride in the presence of pyridine afforded 3,6-di-O-2,3-hexanoyl chitosan isothiocyanate (4a) with a DS of the isothiocyanate groups of 0.70 in high yield, unexpectedly. Compound 4a exhibited high levels of reactivity toward various amines to give the corresponding N-thiocarbamoyl chitosan derivatives in high yields. Other acyl (decanoyl (4b), myristroyl (4c), stearoyl (4d), benzoyl (4e)) chitosan isothiocyanates were also prepared from chitosan (1) in high yields. To evaluate the potential applications of acyl chitosan isothiocyanates, N-(triphenylporphynyl)thiocarbamoyl chitosan derivative 6 with a DS of the triphenylporphynyl groups of 0.46 was prepared from compound 4b. The Langmuir-Blodgett monolayer film of compound 6 gave a good photon-to-electron conversion performance. PMID:25256486

Shibano, Masaya; Nishida, Shouko; Saito, Yasuko; Kamitakahara, Hiroshi; Takano, Toshiyuki

2014-11-26

81

Glass transition temperature of chitosan and miscibility of chitosan\\/poly( N-vinyl pyrrolidone) blends  

Microsoft Academic Search

There are a few communications concerning the relaxation temperature corresponding to the glass transition temperature of chitosan. We succeeded in observing the Tg of chitosan (to be ca. 203°C) by the direct and careful measurement of differential scanning calorimetry (DSC), which had been assumed not to be sensitive enough to detect it. In addition to this observation, the dynamic mechanical

K Sakurai; T Maegawa; T Takahashi

2000-01-01

82

Adsorption of Chromium(VI) on Chitosan?Coated Perlite  

Microsoft Academic Search

Chitosan?coated perlite beads were prepared by drop?wise addition of a liquid slurry containing chitosan and perlite to an alkaline bath. The beads were characterized by SEM and EDS x?ray microanalysis. The chitosan content of the beads was 23%, as determined by a pyrolysis method. Adsorption of hexavalent chromium from aqueous solutions on chitosan?coated perlite beads was studied under both equilibrium

Shameem Hasan; Abburi Krishnaiah; Tushar K. Ghosh; Dabir S. Viswanath; Veera M. Boddu; Edgar D. Smith

2003-01-01

83

Development and characterization of chitosan-PEG-TAT nanoparticles for the intracellular delivery of siRNA  

PubMed Central

Recently, cell-penetrating peptides have been proposed to translocate antibodies, proteins, and other molecules in targeted drug delivery. The proposed study presents the synthesis and characterization of a peptide-based chitosan nanoparticle for small interfering RNA (siRNA) delivery, in-vitro. Specifically, the synthesis included polyethylene glycol (PEG), a hydrophilic polymer, and trans-activated transcription (TAT) peptide, which were chemically conjugated on the chitosan polymer. The conjugation was achieved using N-Hydroxysuccinimide-PEG-maleimide (heterobifunctional PEG) as a cross-linker, with the bifunctional PEG facilitating the amidation reaction through its N-Hydroxysuccinimide group and reacting with the amines on chitosan. At the other end of PEG, the maleimide group was chemically conjugated with the cysteine-modified TAT peptide. The degree of substitution on chitosan with PEG and on PEG with TAT was confirmed using colorimetric assays. The resultant polymer was used to form nanoparticles complexing siRNA, which were then characterized for particle size, morphology, cellular uptake, and cytotoxicity. The nanoparticles were tested in-vitro on mouse neuroblastoma cells (Neuro2a). Particle size and surface charge were characterized and an optimal pH condition and PEG molecular weight were determined to form sterically stable nanoparticles. Results indicate 7.5% of the amines in chitosan polymer were conjugated to the PEG and complete conjugation of TAT peptide was observed on the synthesized PEGylated chitosan polymer. Compared with unmodified chitosan nanoparticles, the nanoparticles formed at pH 6 were monodispersed and of <100 nm in size, exhibiting maximum cell transfection ability and very low cytotoxicity. Thus, this research may be of significance in translocating biotherapeutic molecules for intracellular delivery applications. PMID:23723699

Malhotra, Meenakshi; Tomaro-Duchesneau, Catherine; Saha, Shyamali; Kahouli, Imen; Prakash, Satya

2013-01-01

84

Study on antimicrobial activity of chitosan with different molecular weights  

Microsoft Academic Search

E. coli and Staphylococcus aureus are used to study the antimicrobial activity of chitosan of different molecular weights (MW). The effect of the concentration and MW of chitosan were investigated, respectively, and the antimicrobial mechanism was discussed. For chitosan with MW below 300 kDa, the antimicrobial effect on S. aureus was strengthened as the MW increased. In contrast, the effect

Lian-Ying Zheng; Jiang-Feng Zhu

2003-01-01

85

Effect of chitosan on UASB treating POME during a transition from mesophilic to thermophilic conditions.  

PubMed

The effects of chitosan addition on treatment of palm oil mill effluent were investigated using two lab-scale upflow anaerobic sludge bed (UASB) reactors: (1) with chitosan addition at the dosage of 2 mg chitosan per g volatile suspended solids on the first day of the operation (R1), (2) without chitosan addition (the control, R2). The reactors were inoculated with mesophilic anaerobic sludge which was acclimatized to a thermophilic condition with a stepwise temperature increase of 5 °C from 37 to 57 °C. The OLR ranged from 2.23 to 9.47 kg COD m(-3) day(-1). The difference in biogas production rate increased from non-significant to 18% different. The effluent volatile suspended solids of R1 was 65 mg l(-1) lower than that of R2 on Day 123. 16S rRNA targeted denaturing gradient gel electrophoresis (DGGE) fingerprints of microbial community indicated that some methanogens in the genus Methanosaeta can be detected in R1 but not in R2. PMID:21316949

Khemkhao, Maneerat; Nuntakumjorn, Boonyarit; Techkarnjanaruk, Somkiet; Phalakornkule, Chantaraporn

2011-04-01

86

Inhibition of influenza virus infection with chitosan-sialyloligosaccharides ionic complex.  

PubMed

With the recent emergence of drug-resistant influenza viruses, effective means of preventing and treating these contagious pathogens have become imperative. The binding receptors of influenza virus are sialyloligosaccharides (SOS), which are present on the surfaces of host cells, and are therefore attractive targets for antiviral development. We report the preparation and identification of a novel influenza virus entry inhibitor, designated chitosan-SOS complex (CS complex). The CS complex was formed through noncovalent adsorption between cationic chitosan and anionic SOS, the latter derived from bovine colostrum. The preparation was accomplished in gram quantities from chitosan and bovine colostrum oligosaccharides by a one-step dialysis process. The inhibitory activity of the complex against influenza virus infection was determined by cytotoxicity inhibition assay (IC50=42 ?M). This simple preparation, combined with efficient anti-infective activity and the rich natural availability of chitosan and SOS, highlights the potential of the CS complex as a safe, practical agent for influenza prevention and control. PMID:24702928

Cheng, Shuihong; Zhao, Huiqin; Xu, Yaozu; Yang, Yawei; Lv, Xun; Wu, Peixing; Li, Xuebing

2014-07-17

87

Electrochemical monitoring of indicator-free DNA hybridization by carbon nanotubes-chitosan modified disposable graphite sensors.  

PubMed

Single walled carbon nanotubes (SWCNT)-chitosan (CHIT) modified pencil graphite electrodes (PGEs) were developed for monitoring of DNA hybridization. SWCNT-chitosan modified PGE (CNT-CHIT-PGE), Chitosan modified PGE (CHIT-PGE) and unmodified PGE (bare-PGE) were firstly characterized by using scanning electron microscopy (SEM), and their electrochemical behaviors were investigated using electrochemical impedance spectroscopy (EIS). The concentrations of CHIT, carbon nanotube (CNT) and also amino linked DNA probe etc. were respectively optimized in order to obtain the better working conditions of CNT-CHIT modified PGE in DNA analysis. The sequence selective DNA hybridization related to Hepatitis B virus (HBV) was then explored in the case of hybridization between amino linked HBV probe and its complementary (target), or noncomplementary (NC), or mismatch (MM) sequences, and also hybridization in mixture sample. PMID:22459926

Erdem, Arzum; Muti, Mihrican; Karadeniz, Hakan; Congur, Gulsah; Canavar, Ece

2012-06-15

88

In vitro and in vivo degradation behavior of acetylated chitosan porous beads  

Microsoft Academic Search

Chitosans with different degree of acetylation (DA, 10–50%) were synthesized by the acetylation reaction of deacetylated chitosan and acetic anhydride with different ratios. The porous beads (approx. 500 ?m) fabricated from the acetylated chitosans were used to investigate the degradation behaviors of chitosans with different DA in vitro and in vivo. The in vitro degradation behavior of the acetylated chitosan

Sung Mook Lim; Dae Kun Song; Se Heang Oh; Dong Sin Lee-Yoon; Eun Hee Bae; Jin Ho Lee

2008-01-01

89

Isolation and characterization of chitin and chitosan from marine origin.  

PubMed

Nowadays, chitin and chitosan are produced from the shells of crabs and shrimps, and bone plate of squid in laboratory to industrial scale. Production of chitosan involved deproteinization, demineralization, and deacetylation. The characteristics of chitin and chitosan mainly depend on production processes and conditions. The characteristics of these biopolymers such as appearance of polymer, turbidity of polymer solution, degree of deacetylation, and molecular weight are of major importance on applications of these polymers. This chapter addresses the production processes and conditions to produce chitin, chitosan, and chito-oligosaccharide and methods for characterization of chitin, chitosan, and chito-oligosaccharide. PMID:25081074

Nwe, Nitar; Furuike, Tetsuya; Tamura, Hiroshi

2014-01-01

90

Chitosan-silica hybrid porous membranes.  

PubMed

Chitosan-silica porous hybrids were prepared by a novel strategy in order to improve the mechanical properties of chitosan (CHT) in the hydrogel state. The inorganic silica phase was introduced by sol-gel reactions in acidic medium inside the pores of already prepared porous scaffolds. In order to make the scaffolds insoluble in acidic media chitosan was cross-linked by genipin (GEN) with an optimum GEN concentration of 3.2 wt.%. Sol-gel reactions took place with Tetraethylorthosilicate (TEOS) and 3-glycidoxypropyltrimethoxysilane (GPTMS) acting as silica precursors. GPTMS served also as a coupling agent between the free amino groups of chitosan and the silica network. The morphology study of the composite revealed that the silica phase appears as a layer covering the chitosan membrane pore walls. The mechanical properties of the hybrids were characterized by means of compressive stress-strain measurements. By immersion in water the hybrids exhibit an increase in elastic modulus up to two orders of magnitude. PMID:25063153

Pandis, Christos; Madeira, Sara; Matos, Joana; Kyritsis, Apostolos; Mano, João F; Ribelles, José Luis Gómez

2014-09-01

91

Incorporation of osteogenic and angiogenic small interfering RNAs into chitosan sponge for bone tissue engineering  

PubMed Central

Engineered bone substitutes are being extensively explored in response to growing demand. However, the angiogenesis that occurs during bone formation is often overlooked in scaffold design. In this novel study, we incorporated two small interfering RNAs (siRNAs), ie, small interfering RNA targets casein kinase 2 interaction protein 1 (siCkip-1) and small interfering RNA targets soluble VEGF receptor 1 (siFlt-1), which can promote osteogenesis and angiogenesis, into a chitosan sponge. This scaffold could maintain siRNAs for over 2 weeks in neutral phosphate-buffered saline and degraded rapidly in the presence of lysozyme. The chitosan sponge with siCkip-1 and siFlt-1 in vitro bioactivity was investigated using mesenchymal stem cells. Target genes were significantly suppressed, and osteocalcin, alkaline phosphatase, and vascular endothelial growth factor were significantly upregulated. Alizarin Red staining revealed that mineralization of the extracellular matrix was markedly enhanced by dual transfection. Further analysis by immunofluorescence confirmed that the siRNA-modified scaffold simultaneously improved the expression of osteocalcin and von Willebrand factor. In vivo testing in a skull critical-size defect model showed marked bone regeneration in rats treated with siCkip-1 and siFlt-1. In conclusion, chitosan sponge containing osteogenic and angiogenic siRNAs may be used as a scaffold for bone regeneration. The dual siRNA concept may also be useful in the biofunctionalization of other materials.

Jia, Sen; Yang, Xinjie; Song, Wen; Wang, Lei; Fang, Kaixiu; Hu, Zhiqiang; Yang, Zihui; Shan, Chun; Lei, Delin; Lu, Bin

2014-01-01

92

Growth rate inhibition of phytopathogenic fungi by characterized chitosans.  

PubMed

The inhibitory effects of fifteen chitosans with different degrees of polymerization (DP) and different degrees of acetylation (FA) on the growth rates (GR) of four phytopathogenic fungi (Alternaria alternata, Botrytis cinerea, Penicillium expansum, and Rhizopus stolonifer) were examined using a 96-well microtiter plate and a microplate reader. The minimum inhibitory concentrations (MICs) of the chitosans ranged from 100 ?g ×mL(-1) to 1,000 ?g ×mL(-1) depending on the fungus tested and the DP and FA of the chitosan. The antifungal activity of the chitosans increased with decreasing FA. Chitosans with low FA and high DP showed the highest inhibitory activity against all four fungi. P. expansum and B. cinerea were relatively less susceptible while A. alternata and R. stolonifer were relatively more sensitive to the chitosan polymers. Scanning electron microscopy of fungi grown on culture media amended with chitosan revealed morphological changes. PMID:24031893

Oliveira Junior, Enio N; Gueddari, Nour E El; Moerschbacher, Bruno M; Franco, Telma T

2012-04-01

93

Chitosan Fibers Modified with HAp/?-TCP Nanoparticles  

PubMed Central

This paper describes a method for preparing chitosan fibers modified with hydroxyapatite (HAp), tricalcium phosphate (?-TCP), and HAp/?-TCP nanoparticles. Fiber-grade chitosan derived from the northern shrimp (Pandalus borealis) and nanoparticles of tricalcium phosphate (?-TCP) and hydroxyapatite (HAp) suspended in a diluted chitosan solution were used in the investigation. Diluted chitosan solution containing nanoparticles of Hap/?-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/?-TCP were characterized by a level of tenacity and calcium content one hundred times higher than that of regular chitosan fibers. PMID:22174598

Wawro, Dariusz; Pighinelli, Luciano

2011-01-01

94

Differential interactions and structural stability of chitosan oligomers with human serum albumin and ?-1-glycoprotein.  

PubMed

Chitosan is a naturally occurring deacetylated derivative of chitin with versatile biological activities. Here, we studied the interaction of chitosan oligomers with low degree of polymerization such as chitosan monomer (CM), chitosan dimer (CD), and chitosan trimer (CT) with human serum albumin (HSA) a major blood carrier protein and ?-1-glycoprotein (AGP). Since, HSA and AGP are the two important plasma proteins that determine the drug disposition and affect the fate of distribution of drugs. Fluorescence emission spectra indicated that CM, CD, and CT had binding constants of KCM = 6.2 ± .01 × 10(5) M(-1), KCD = 5.0 ± .01 × 10(4) M(-1), and KCT = 1.6 ± .01 × 10(6) M(-1), respectively, suggesting strong binding with HSA. However, binding of chitooligomers with AGP was insignificant. Thermodynamic and molecular docking analysis indicated that hydrogen bonds and also hydrophobic interaction played an important role in stabilizing the HSA-chitooligomer complexes with free energies of -7.87, -6.35, and -8.4?Kcal/mol for CM, CD, and CT, respectively. Further, circular dichroism studies indicated a minor unfolding of HSA secondary structure, upon interaction with chitooligomers, which are supported with fluctuations of root mean square deviation (RMSD) and radius of gyration (Rg) of HSA. Docking analysis revealed that all three chitooligomers were bound to HSA within subdomain IIA (Site I). In addition, RMSD and Rg analysis depicted that HSA-chitooligomer complexes stabilized at around 4.5 ns. These results suggest that HSA might serve as a carrier in delivering chitooligomers to target tissues than AGP which has pharmacological importance. PMID:24359035

Gokara, Mahesh; Kimavath, Geetha Bai; Podile, Appa Rao; Subramanyam, Rajagopal

2015-01-01

95

Nasal delivery of insulin using chitosan microspheres.  

PubMed

Nasal delivery of insulin is an alternative route for administration of this drug. The objective of this study was preparation of chitosan microspheres for insulin nasal delivery. After preparation of insulin chitosan microspheres by emulsification-cross linking process, the effect of chitosan quantity (200-400mg), cross-linker type (ascorbic acid or ascorbyl palmitate) and amount (70-140 mg) were studied on the morphology, particle size, loading efficiency, flow and release of insulin from the microspheres by a factorial design. Optimized formulation was administered nasally in four groups of diabetic rats and their serum insulin levels were analysed by the insulin enzyme immunoassay kit and the serum glucose by the glucose oxidase kits. Insulin loading in microspheres was between 4.7-6.4% w/w, preparation efficiency more than 65% and mean particle size was 20-45 microm. In most cases, drug released followed a Higuchi model. Ascorbic acid caused an increase in stability, particle size and T50%, while decreased the loading efficiency and production efficiency. Increasing the chitosan content, increased particle size, flow and insulin release rate form the microspheres. The increase of cross-linking percentage decreased the flow and size of the microspheres while increase of cross-linking percentage promoted the stability and decreased DE8% of insulin. Microspheres containing 400mg of chitosan and 70mg ascorbyl palmitate caused a 67% reduction of blood glucose compared to i.v. route and absolute bioavaliability of insulin was 44%. The results showed that chitosan microspheres of insulin are absorbable from nasal route. PMID:15799226

Varshosaz, J; Sadrai, H; Alinagari, R

2004-11-01

96

Solid polymer electrolyte from phosphorylated chitosan  

NASA Astrophysics Data System (ADS)

Recently, the need of secondary battery application continues to increase. The secondary battery which using a liquid electrolyte was indicated had some weakness. A solid polymer electrolyte is an alternative electrolytes membrane which developed in order to replace the liquid electrolyte type. In the present study, the effect of phosphorylation on to polymer electrolyte membrane which synthesized from chitosan and lithium perchlorate salts was investigated. The effect of the component's composition respectively on the properties of polymer electrolyte, was carried out by analyzed of it's characterization such as functional groups, ion conductivity, and thermal properties. The mechanical properties i.e tensile resistance and the morphology structure of membrane surface were determined. The phosphorylation processing of polymer electrolyte membrane of chitosan and lithium perchlorate was conducted by immersing with phosphoric acid for 2 hours, and then irradiated on a microwave for 60 seconds. The degree of deacetylation of chitosan derived from shrimp shells was obtained around 75.4%. Relative molecular mass of chitosan was obtained by viscometry method is 796,792 g/mol. The ionic conductivity of chitosan membrane was increase from 6.33 × 10-6 S/cm up to 6.01 × 10-4 S/cm after adding by 15 % solution of lithium perchlorate. After phosphorylation, the ionic conductivity of phosphorylated lithium chitosan membrane was observed 1.37 × 10-3 S/cm, while the tensile resistance of 40.2 MPa with a better thermal resistance. On the strength of electrolyte membrane properties, this polymer electrolyte membrane was suggested had one potential used for polymer electrolyte in field of lithium battery applications.

Fauzi, Iqbal; Arcana, I. Made

2014-03-01

97

Preparation of a novel chitosan derivative and use in water treatment  

Microsoft Academic Search

Chitosan-betaine derivative was prepared by chitosan and betaine hydrochloride through dry process in the presence of dicyandiamide. The product exhibited solubility, practical flocculating property and antibacterial efficacy. Keywords—Chitosan-betaine derivative; Water treatment

Min Zhang; ChengYu Tan; Liang Kong; LuChen Jin

2011-01-01

98

Heparin-functionalized chitosan scaffolds for bone tissue engineering.  

PubMed

The aim of this study is to investigate the effects of heparin-functionalized chitosan scaffolds on the activity of preosteoblasts. The chitosan scaffolds having the pore size of ?100 ?m were prepared by a freeze-drying method. Two different methods for immobilization of heparin to chitosan scaffolds were successfully performed. In the first method, functionalization of the scaffolds was achieved by means of electrostatic interactions between negatively charged heparin and positively charged chitosan. The covalent immobilization of heparin to chitosan scaffolds by 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDAC) and N-hydroxysuccinimide (NHS) was used as a second immobilization method. Morphology, proliferation, and differentiation of MC3T3-E1 preosteoblasts on heparin-functionalized chitosan scaffolds were investigated in vitro. The results indicate that covalently bound heparin containing chitosan scaffolds (CHC) stimulate osteoblast proliferation compared to other scaffolds, that is, unmodified chitosan scaffolds (CH), electrostatically bound heparin containing chitosan scaffolds (EHC), and CH+free heparin (CHF). SEM images also proved the stimulative effect of covalently bound heparin on the proliferation of preosteoblasts. Alkaline phosphatase (ALP) and osteocalcin (OCN) levels of cells proliferated on CHC and EHC were also higher than those for CH and CHF. In vitro studies have demonstrated that chitosan scaffolds increase viability and differentiation of MC3T3-E1 cells especially in the presence of immobilized heparin. PMID:21333274

Gümü?derelio?lu, Menem?e; Aday, Sezin

2011-04-01

99

Chitosan oligosaccharide-stabilized ferrimagnetic iron oxide nanocubes for magnetically modulated cancer hyperthermia.  

PubMed

Magnetic nanoparticles have gained significant attention as a therapeutic agent for cancer treatment. Herein, we developed chitosan oligosaccharide-stabilized ferrimagnetic iron oxide nanocubes (Chito-FIONs) as an effective heat nanomediator for cancer hyperthermia. Dynamic light scattering and transmission electron microscopic analyses revealed that Chito-FIONs were composed of multiple 30-nm-sized FIONs encapsulated by a chitosan polymer shell. Multiple FIONs in an interior increased the total magnetic moments, which leads to localized accumulation under an applied magnetic field. Chito-FIONs also exhibited superior magnetic heating ability with a high specific loss power value (2614 W/g) compared with commercial superparamagnetic Feridex nanoparticles (83 W/g). The magnetically guided Chito-FIONs successfully eradicated target cancer cells through caspase-mediated apoptosis. Furthermore, Chito-FIONs showed excellent antitumor efficacy on an animal tumor model without any severe toxicity. PMID:22588093

Bae, Ki Hyun; Park, Mihyun; Do, Min Jae; Lee, Nohyun; Ryu, Ji Hyun; Kim, Gun Woo; Kim, Cheolgi; Park, Tae Gwan; Hyeon, Taeghwan

2012-06-26

100

Chitosan-based nanocarriers for antimalarials  

NASA Astrophysics Data System (ADS)

The objective of this research was to synthesize and characterize chitosan-based liquid and solid materials with unique absorptive and mechanical properties as carriers for quinine - one of the most used antimalarial drug. The use of chitosan (CTS) as base in polyelectrolyte complex systems, to prepare solid release systems as sponges is presented. The preparation by double emulsification of CTS hydrogels carrying quinine as anti-malarial drug is reported. The concentration of quinine in the CTS hydrogel was 0.08 mmol. Chitosan - drug loaded hydrogel was used to generate solid sponges by freeze-drying at -610°C and 0.09 atm. Structural investigations of the solid formulations were done by Fourier-transformed infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-VIS), spectrofluorimetry, differential scanning calorimetry (DSC) and X-ray diffractometry. The results indicated that the drug molecule is forming temporary chelates in CTS hydrogels and sponges. Electron paramagnetic resonance (EPR) demonstrates the presence of free radicals in a wide range and the antioxidant activity for chitosan - drug supramolecular cross-linked assemblies.

Dreve, Simina; Kacso, Iren; Popa, Adriana; Raita, Oana; Bende, A.; Borodi, Gh.; Bratu, I.

2012-02-01

101

Photochemical tissue bonding with chitosan adhesive films  

PubMed Central

Background Photochemical tissue bonding (PTB) is a promising sutureless technique for tissue repair. PTB is often achieved by applying a solution of rose bengal (RB) between two tissue edges, which are irradiated by a green laser to crosslink collagen fibers with minimal heat production. In this study, RB has been incorporated in chitosan films to create a novel tissue adhesive that is laser-activated. Methods Adhesive films, based on chitosan and containing ~0.1 wt% RB were manufactured and bonded to calf intestine by a solid state laser (? = 532 nm, Fluence~110 J/cm2, spot size~0.5 cm). A single-column tensiometer, interfaced with a personal computer, tested the bonding strength. K-type thermocouples recorded the temperature (T) at the adhesive-tissue interface during laser irradiation. Human fibroblasts were also seeded on the adhesive and cultured for 48 hours to assess cell growth. Results The RB-chitosan adhesive bonded firmly to the intestine with adhesion strength of 15 ± 2 kPa, (n = 31). The adhesion strength dropped to 0.5 ± 0.1 (n = 8) kPa when the laser was not applied to the adhesive. The average temperature of the adhesive increased from 26°C to 32°C during laser exposure. Fibroblasts grew confluent on the adhesive without morphological changes. Conclusion A new biocompatible chitosan adhesive has been developed that bonds photochemically to tissue with minimal temperature increase. PMID:20825632

2010-01-01

102

Photochemical tissue bonding with chitosan adhesive films  

Microsoft Academic Search

BACKGROUND: Photochemical tissue bonding (PTB) is a promising sutureless technique for tissue repair. PTB is often achieved by applying a solution of rose bengal (RB) between two tissue edges, which are irradiated by a green laser to crosslink collagen fibers with minimal heat production. In this study, RB has been incorporated in chitosan films to create a novel tissue adhesive

Antonio Lauto; Damia Mawad; Matthew Barton; Abhishek Gupta; Sabine C Piller; James Hook

2010-01-01

103

Chitosan contribution on wool treatments with enzyme  

Microsoft Academic Search

In a previous research work, it was observed that the application of biopolymer chitosan (CHT) on wool fabrics before the enzymatic treatment promotes an increase of the weight loss. In order to deep on the role played by CHT, several experimental conditions have been selected according to a hybrid experimental design and different parameters, such as weight loss and shrink-resist

S. Vílchez; A. M. Manich; P. Jovancic; P. Erra

2008-01-01

104

Chitosan Adhesive Films for Photochemical Tissue Bonding  

NASA Astrophysics Data System (ADS)

Photochemical tissue bonding (PTB) is a promising sutureless technique for tissue repair. PTB is often achieved by applying a solution of rose bengal (RB) between two tissue edges, which are irradiated by a green laser to crosslink collagen fibers with minimal heat production. In this study, RB has been incorporated in chitosan films to create a novel tissue adhesive that is laser-activated. Materials and Methods. Adhesive films, based on chitosan and containing ˜0.1wt% RB were manufactured and bonded to calf intestine by a solid state laser (wavelength = 532 nm, Fluence ˜110 J/cm2, spot size ˜5 mm). A single-column tensiometer, interfaced with a personal computer, tested the bonding strength. K-type thermocouples recorded the temperature (T) at the adhesive-tissue interface during laser irradiation. Human fibroblasts were also seeded on the adhesive and cultured for 48 hours to assess cell growth. Results and Conclusion. The RB-chitosan adhesive bonded firmly to the intestine (15±2 kPa, n = 31). The adhesion strength dropped to 0.5±0.1 kPa (n = 8) when the laser was not applied to the adhesive. The average temperature of the adhesive increased from 26 °C to 32 °C during laser exposure. Fibroblasts grew confluent on the adhesive without morphological changes. A new biocompatible chitosan adhesive has been developed that bonds photochemically to tissue with minimal temperature increase.

Lauto, Antonio; Mawad, Damia; Barton, Matthew; Piller, Sabine C.; Longo, Leonardo

2011-08-01

105

Potential of quaternization-functionalized chitosan fiber for wound dressing.  

PubMed

Quaternization-functionalized chitosan fibers were successfully prepared by using 2,3-epoxypropyl trimethyl ammonium chloride as a quaternized reagent reacted with chitosan fiber. FTIR and (1)H NMR were used to characterize the structure of quaternized chitosan fibers (QCFs). The swelling behavior and mechanical property of QCFs were studied. The results showed that, QCFs had higher liquid absorption capacity than chitosan fiber, while the tensile strength and elongation at break of QCFs were lower than those of chitosan fiber. The antibacterial activity of the QCF had been evaluated by Gram-positive bacteria Staphylococcus aureus (S. aureus). The results indicated that, the antibacterial activity of QCF against S. aureus was stronger than that of chitosan fiber. Indirect cytotoxicity assessment of the fibers indicated that QCF was nontoxic to the L929 cell with relatively low extraction concentration. This novel fiber would be used as potential wound dressing for skin regeneration. PMID:23089086

Zhou, Yingshan; Yang, Hongjun; Liu, Xin; Mao, Jun; Gu, Shaojin; Xu, Weilin

2013-01-01

106

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

NASA Astrophysics Data System (ADS)

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 antibacterial testing of the nanofiber mats were performed according to AATCC-100 protocol. PVA/CS/CIA system was found to have superior antibacterial action over PVA/CS/thiolchitosan counterparts. In the last part of the thesis, chitosan nanoparticles were prepared; for the first time in the literature instead of Tripolyphosphate (TPP), via ionic crosslinking with hexametaphosphate (HMP). A systematic study was conducted to apply the chitosan/HMP nanoparticles as a hydrophilic drug carrier for protein drugs. Chitosan/HMP systems were found to be unstable in the acidic medium. The optimum complexation conditions were established as pH 5 and the nanoparticles showed better stability at 21 days. Chitosan concentration plays an important role in improving particles stability by increasing zeta potential; however, it adversely affects the particles size. BSA loading capacity of chitosan/HMP was higher, 96.3%, than that of TPP, 91.87%, equivalents due to larger average size.

Abdelgawad, Abdelrahman Mohamed

107

Synthesis, characterization and antibacterial activity of salicyloyl chitosan  

Microsoft Academic Search

Salicyloyl chitosan (SCS) with different degrees of substitution (DS) and molecular weight (MW) were synthesized from chitosan and salicylic acid. Their structures were characterized by UV, FTIR, 1H NMR and XRD, which showed that the acylate reaction took place at the N-position of chitosan. The DS value of SCS ranged from 0.10 to 0.71. The antibacterial activities were assessed according

Guanghua He; Xu Chen; Yihua Yin; Hua Zheng; Xiong Xiong; Yumin Du

2011-01-01

108

Antibacterial activity of chitosan-based matrices on oral pathogens  

Microsoft Academic Search

Chitosan is a well sought-after polysaccharide in biomedical applications due to its biocompatibility, biodegradability to\\u000a non-toxic substances, and ease of fabrication into various configurations. However, alterations in the anti-bacterial properties\\u000a of chitosan in various forms is not completely understood. The objective of this study was to evaluate the anti-bacterial\\u000a properties of chitosan matrices in different configurations against two pathogens—Gram-positive Streptococcus

Aparna R. Sarasam; Phoebe Brown; Sharukh S. Khajotia; John J. Dmytryk; Sundararajan V. Madihally

2008-01-01

109

Impact of salt form and molecular weight of chitosan on swelling and drug release from chitosan matrix tablets.  

PubMed

Magnetic resonance imaging (MRI) and gravimetric techniques were used to assess swelling and erosion behaviors of hydrophilic matrix tablets made of chitosan. The impact of salt form, molecular weight (MW) and dissolution medium on swelling behavior and drug (theophylline) release was studied. The matrix tablets made of chitosan glycolate (CGY) showed the greatest swelling in both acid and neutral media, compared to chitosan aspartate, chitosan glutamate and chitosan lactate. MRI illustrated that swelling region of CGY in both media was not different in the first 100 min but glassy region (dry core) in 0.1N HCl was less than in pH 6.8 buffer. The tablets prepared from chitosan with high MW swelled greater than those of low MW. Moreover, CGY can delay drug release in the acid condition due to thick swollen gel and low erosion rate. Therefore, CGY may be suitably applied as sustained drug release polymer or enteric coating material. PMID:23769512

Huanbutta, Kampanart; Cheewatanakornkool, Kamonrak; Terada, Katsuhide; Nunthanid, Jurairat; Sriamornsak, Pornsak

2013-08-14

110

Biochemical properties of Hemigraphis alternata incorporated chitosan hydrogel scaffold.  

PubMed

In this work, Hemigraphis alternata extract incorporated chitosan scaffold was synthesized and characterized for wound healing. The antibacterial activity of Hemigraphis incorporated chitosan scaffold (HIC) against Escherichia coli and Staphylococcus aureus was evaluated which showed a reduction in total colony forming units by 45-folds toward E. coli and 25-fold against S. aureus respectively. Cell viability studies using Human Dermal Fibroblast cells (HDF) showed 90% viability even at 48 h when compared to the chitosan control. The herbal scaffold made from chitosan was highly haemostatic and antibacterial. The obtained results were in support that the herbal scaffold can be effectively applied for infectious wounds. PMID:23399189

Annapoorna, M; Sudheesh Kumar, P T; Lakshman, Lakshmi R; Lakshmanan, Vinoth-Kumar; Nair, Shantikumar V; Jayakumar, R

2013-02-15

111

Characterization of interactions between chitosan and an anionic surfactant.  

PubMed

Chitosan is a cationic biopolymer that has many potential applications in the food industry because of its unique nutritional and physiochemical properties. Many of these properties depend on its ability to interact with anionic surface-active molecules, such as phospholipids, surfactants, and bile acids. The purpose of this study was to characterize the interaction between chitosan and a model anionic surfactant (sodium dodecyl sulfate, SDS) using isothermal titration calorimetry (ITC), surfactant-selective electrode (SSE), and turbidity measurements. ITC and SSE indicated that SDS bound strongly to chitosan via a highly exothermic interaction. The turbidity measurements indicated that chitosan formed insoluble complexes with SDS that strongly scattered light. The chitosan bound approximately 4 mM of SDS per 0.1 wt % chitosan before becoming saturated with surfactant. The SDS-chitosan interaction was weakened appreciably by the presence of 100 mM NaCl, which suggested that it was electrostatic in origin. This study provides information about the origin and characteristics of molecular interactions between chitosan and anionic surface-active lipids that may be useful for the rational design of chitosan-based food ingredients with specific nutritional and functional characteristics, e.g., cholesterol lowering or fat replacement. PMID:14969561

Thongngam, Masubon; McClements, D Julian

2004-02-25

112

Chitosan in nasal delivery systems for therapeutic drugs.  

PubMed

There is an obvious need for efficient and safe nasal absorption enhancers for the development of therapeutically efficacious nasal products for small hydrophilic drugs, peptides, proteins, nucleic acids and polysaccharides, which do not easily cross mucosal membranes, including the nasal. Recent years have seen the development of a range of nasal absorption enhancer systems such as CriticalSorb (based on Solutol HS15) (Critical Pharmaceuticals Ltd), Chisys based on chitosan (Archimedes Pharma Ltd) and Intravail based on alkylsaccharides (Aegis Therapeutics Inc.), that is presently being tested in clinical trials for a range of drugs. So far, none of these absorption enhancers have been used in a marketed nasal product. The present review discusses the evaluation of chitosan and chitosan derivatives as nasal absorption enhancers, for a range of drugs and in a range of formulations such as solutions, gels and nanoparticles and finds that chitosan and its derivatives are able to efficiently improve the nasal bioavailability. The revirtew also questions whether chitosan nanoparticles for systemic drug delivery provide any real improvement over simpler chitosan formulations. Furthermore, the review also evaluates the use of chitosan formulations for the improvement of transport of drugs directly from the nasal cavity to the brain, based on its mucoadhesive characteristics and its ability to open tight junctions in the olfactory and respiratory epithelia. It is found that the use of chitosan nanoparticles greatly increases the transport of drugs from nose to brain over and above the effect of simpler chitosan formulations. PMID:24818769

Casettari, Luca; Illum, Lisbeth

2014-09-28

113

In situ chitosan gelation initiated by atmospheric plasma treatment.  

PubMed

This work reports on the feasibility of atmospheric dielectric barrier discharge (DBD) plasma as a novel synthetic pathway for the liquid phase gelation of chitosan. The DBD plasma chitosan gelation process did not significantly alter the chemical structure of the biopolymer as confirmed by FTIR study. However, the oxidation processes and local heating effect associated with the solvent evaporation during the plasma treatment could provoke both reaction of chitosan degradation and the cleavage of ?-1-4-glycosidic linkages with the concomitant generation of aldehyde groups able to crosslink via Schiff-base with amino groups from other chitosan molecules. Shear viscosity measurements suggested the formation of chitosan fragments of lower molecular weight after the plasma treatment of 1% (w/v) chitosan and fragments of higher molecular weight after the plasma treatment of 2% (w/v) chitosan. The crosslinking density of hydrogels generated during the in situ DBD plasma chitosan gelation process increased as a function of the treatment time and concentration of chitosan. As of consequence of the increase of the cross-linking density, the equilibrium swelling ratio and water content decreased significantly. PMID:24528756

Molina, R; Jovancic, P; Vilchez, S; Tzanov, T; Solans, C

2014-03-15

114

Chitosan intercalated montmorillonite: Preparation, characterization and cationic dye adsorption  

Microsoft Academic Search

Chitosan intercalated montmorillonite (Chi-MMT) was prepared by dispersing sodium montmorillonite (Na+-MMT) into chitosan solution at 60 °C for 24 h. The Chi-MMT was characterized by XRD, XRF and FT-IR. The intercalation was accomplished via the ion-exchange of Na+ ions with –NH3+ of chitosan, resulting in the expansion of d001 from 1.42 nm of Na+-MMT to 2.21 nm of Chi-MMT. The chitosan content in the

Pathavuth Monvisade; Punnama Siriphannon

2009-01-01

115

Studies of chitosan/organic acid/Eudragit RS/RL-coated system for colonic delivery.  

PubMed

Prednisolone (PDS) beads were coated sequentially with (i) innermost hydrophobic layer of Eudragit RS/RL, (ii) middle drug release-triggering layer of chitosan, organic acid and Eudragit RS/RL, and (iii) outermost enteric coating layer. Continuous dissolution studies were carried out in artificial gastric fluid (pH 1.2), followed by intestinal fluid (pH 6.8), and finally in colonic fluid (pH 4 and 6) with and without beta-glucosidase. While drug release was prevented in the gastric and small-intestinal fluids, a continuous release was observed in the colonic fluid. Succinic acid provided the fastest rate of release in the colonic fluid compared to citric, tartaric or malic acid. A combined mechanism of drug release is proposed, which considers the swelling of chitosan and Eudragit RS/RL in the presence of succinic acid possibly via electrostatic interaction between the amine groups of chitosan/quaternary ammonium groups of Eudragit RS/RL and the carboxyl groups of succinic acid in aqueous medium. The results of plasma pharmacokinetic studies in Sprague-Dawley rats showed that the developed system provided a significant delay (T(max) 9.3 h) in the absorption profile of PDS compared with simple enteric-coated (T(max) 4 h) or powder (T(max) 1 h) formulation that was taken as proof for the colon-targeted delivery. PMID:18835342

Kaur, Karanjit; Kim, Kwonho

2009-01-21

116

Multimodal in vivo MRI and NIRF imaging of bladder tumor using peptide conjugated glycol chitosan nanoparticles  

NASA Astrophysics Data System (ADS)

Exact detection and complete removal of cancer is a key point to minimize cancer recurrence. However, it is currently very difficult to detect small tumors inside human body and continuously monitor tumors using a non-invasive imaging modality. Presently, positron emission tomography (PET) can provide the most sensitive cancer images in the human body. However, PET imaging has very limited imaging time because they typically use isotopes with short halflives. PET imaging cannot also visualize anatomical information. Magnetic resonance imaging (MRI) can provide highresolution images inside the body but it has a low sensitivity, so MRI contrast agents are necessary to enhance the contrast of tumor. Near infrared fluorescent (NIRF) imaging has a good sensitivity to visualize tumor using optical probes, but it has a very limited tissue penetration depth. Therefore, we developed multi-modality nanoparticles for MRI based diagnosis and NIRF imaging based surgery of cancer. We utilized glycol chitosan of 350 nm as a vehicle for MRI contrast agents and NIRF probes. The glycol chitosan nanoparticles were conjugated with NIRF dye, Cy5.5 and bladder cancer targeting peptides to increase the internalization of cancer. For MR contrast effects, iron oxide based 22 nm nanocubes were physically loaded into the glycol chitosan nanoparticles. The nanoparticles were characterized and evaluated in bladder tumor bearing mice. Our study suggests the potential of our nanoparticles by both MRI and NIRF imaging for tumor diagnosis and real-time NIRF image-guided tumor surgery.

Key, Jaehong; Dhawan, Deepika; Knapp, Deborah W.; Kim, Kwangmeyung; Kwon, Ick Chan; Choi, Kuiwon; Leary, James F.

2012-03-01

117

3D porous chitosan scaffolds suit survival and neural differentiation of dental pulp stem cells.  

PubMed

A key aspect of cell replacement therapy in brain injury treatment is construction of a suitable biomaterial scaffold that can effectively carry and transport the therapeutic cells to the target area. In the present study, we created small 3D porous chitosan scaffolds through freeze-drying, and showed that these can support and enhance the differentiation of dental pulp stem cells (DPSCs) to nerve cells in vitro. The DPSCs were collected from the dental pulp of adult human third molars. At a swelling rate of ~84.33 ± 10.92 %, the scaffold displayed high porosity and interconnectivity of pores, as revealed by SEM. Cell counting kit-8 assay established the biocompatibility of the chitosan scaffold, supporting the growth and survival of DPSCs. The successful neural differentiation of DPSCs was assayed by RT-PCR, western blotting, and immunofluorescence. We found that the scaffold-attached DPSCs showed high expression of Nestin that decreased sharply following induction of differentiation. Exposure to the differentiation media also increased the expression of neural molecular markers Microtubule-associated protein 2, glial fibrillary acidic protein, and 2',3'-cyclic nucleotide phosphodiesterase. This study demonstrates that the granular 3D chitosan scaffolds are non-cytotoxic, biocompatible, and provide a conducive and favorable micro-environment for attachment, survival, and neural differentiation of DPSCs. These scaffolds have enormous potential to facilitate future advances in treatment of brain injury. PMID:24789753

Feng, Xingmei; Lu, Xiaohui; Huang, Dan; Xing, Jing; Feng, Guijuan; Jin, Guohua; Yi, Xin; Li, Liren; Lu, Yuanzhou; Nie, Dekang; Chen, Xiang; Zhang, Lei; Gu, Zhifeng; Zhang, Xinhua

2014-08-01

118

Chitosan: antimicrobial activity, interactions with food components and applicability as a coating on fruit and vegetables  

Microsoft Academic Search

Chitosan has recently gained more interest due to its applications in food and pharmaceutics. Among others, the antimicrobial activity of chitosan has been pointed out as one of its most interesting properties of chitosan.The aim of this study was threefold: (1) the quantification of the antimicrobial effect of chitosan with a deacetylation degree of 94% and a molecular weight of

F Devlieghere; A Vermeulen; J Debevere

2004-01-01

119

Solid-state and mechanical properties of aqueous chitosan-amylose starch films plasticized with polyols  

Microsoft Academic Search

agent, gel and emulsion agent, and most recently as a film- coating agent. Higher molecular weight chitosans have been reported to have good film-forming properties as a result of intra- and intermolecular hydrogen bonding.2 The chitosan film characteristics, however, varied from one report to an- other. Differences in the sources of chitin used to produce chitosan, chitosan material properties, solvents

Mirna Fernández Cervera; Jyrki Heinämäki; Karin Krogars; Anna C. Jörgensen; Milja Karjalainen; Antonio Iraizoz Colarte; Jouko Yliruusi

2004-01-01

120

Development of Schwann cell-seeded conduit using chitosan-based biopolymers for nerve repair  

Microsoft Academic Search

The purpose of this study is to develop biodegradable nerve guidance conduits seeded with Schwann cells (SC) using chitosan-based biopolymers for improving nerve regeneration. Chitosan, prepared from alkaline hydrolysis of chitin, is a natural polysaccharide biopolymer, having biocompatibility and biodegradability. In this study, chitosan and chitosan-gelatin membranes were prepared, characterized, and evaluated. The SC isolated from rat sciatic nerve was

Atul Khataokar; Nolan Skop; Haesun Kim; Bryan Pfister; Cheul H. Cho

2010-01-01

121

Chemical coupling of thiolated chitosan to preformed liposomes improves mucoadhesive properties  

PubMed Central

Aim To develop mucoadhesive liposomes by anchoring the polymer chitosan-thioglycolic acid (chitosan-TGA) to the liposomal surface to target intestinal mucosal membranes. Methods Liposomes consisting of phosphatidylcholine (POPC) and a maleimide-functionalized lipid were incubated with chitosan-TGA, leading to the formation of a thioether bond between free SH-groups of the polymer and maleimide groups of the liposome. Uncoated and newly generated thiomer-coated liposomes were characterized according to their size, zeta potential, and morphology using photon correlation spectroscopy and transmission electron microscopy. The release behavior of calcitonin and the fluorophore/quencher-couple ANTS/DPX (8-aminonaphthalene-1,3,6-trisulfonic acid/p-xylene-bis- pyridinium bromide) from coated and uncoated liposomes, was investigated over 24 hours in simulated gastric and intestinal fluids. To test the mucoadhesive properties of thiomer-coated and uncoated liposomes in-vitro, we used freshly excised porcine small intestine. Results Liposomes showed a concentration-dependent increase in size – from approximately 167 nm for uncoated liposomes to 439 nm for the highest thiomer concentration used in this study. Likewise, their zeta potentials gradually increased from about ?38 mV to +20 mV, clearly indicating an effective coupling of chitosan-TGA to the surface of liposomes. As a result of mucoadhesion tests, we found an almost two-fold increase in the mucoadhesion of coupled liposomes relative to uncoupled ones. With fluorescence microscopy, we saw a tight adherence of coated particles to the intestinal mucus. Conclusion Taken together, our current results indicate that thiomer-coated liposomes possess a high potential to be used as an oral drug-delivery system. PMID:22679365

Gradauer, Kerstin; Vonach, Caroline; Leitinger, Gerd; Kolb, Dagmar; Frohlich, Eleonore; Roblegg, Eva; Bernkop-Schnurch, Andreas; Prassl, Ruth

2012-01-01

122

Stability testing of alginate-chitosan films.  

PubMed

Pellets containing rutin prepared by the extrusion/spheronization method were coated with sodium alginate-chitosan film. Important quality parameters in the pellets before coating were determined, and after coating the dissolution profiles of the drug were evaluated in dissolution media of the pH corresponding to the conditions in the gastrointestinal tract. Samples of coated pellets were located in the boxes for stability testing under different conditions, i.e. 25 degrees C and 60% of relative humidity (RH); 30 degrees C and 65% RH and 40 degrees C and 75% RH. After 1, 3, 6, 9 and 12 months (or 1, 3 and 6 months), the dissolution test was repeated and compared with the original profiles using similarity factors. All similarity factor values above 50 indicate excellent stability of alginate-chitosan films. PMID:22536650

Rabisková, Miloslava; Dvorácková, Katerina; Kofronvá, Lenka

2012-02-01

123

Preparation and characterization of nonaarginine-modified chitosan nanoparticles for siRNA delivery.  

PubMed

Chitosan-based nanoparticles have been widely used as a carrier for gene delivery due to their low toxicity and the positively charged amino groups in chitosan. In this study, we hypothesized that introduction of nonaarginine to chitosan could improve its ability to form a complex with siRNA, as well as enhance the cellular uptake and transfection efficiency of chitosan-based nanoparticles. To this end, a peptide with nine repeating arginine residues was chemically coupled to the chitosan backbone, and various characteristics of nonaarginine-chitosan/siRNA nanoparticles were investigated. The mean diameter and zeta potential of the nonaarginine-chitosan/siRNA nanoparticles were dependent on the amount of nonaarginine conjugated to chitosan. Nonaarginine-modified chitosan/siRNA nanoparticles demonstrated enhanced cellular association and transfection efficiency in vitro, while maintaining a low level of cytotoxicity. In conclusion, nonaarginine-modified chitosan should be considered a potential carrier for various gene delivery applications. PMID:23218265

Park, Soyeon; Jeong, Eun Ju; Lee, Jangwook; Rhim, Taiyoun; Lee, Sang Kyung; Lee, Kuen Yong

2013-01-30

124

Effects of concentration, degree of deacetylation and molecular weight on emulsifying properties of chitosan.  

PubMed

Chitosan has excellent emulsifying properties. Emulsifying activity and stability of chitosan were determined by integrated light scattering technique and turbidimetric method. The effects of concentration, degree of deacetylation and molecular weight on emulsifying properties of chitosan were systematically studied in the paper. Emulsifying activity of chitosan initially increased, arrived at the peak at 0.75% and then declined, while emulsifying stability continuously increased with a rise of chitosan concentration from 0.25% to 1.25%. Emulsifying activity and stability of chitosan initially decreased and reached the minimum, then increased with the rise of degree of deacetylation. Chitosan with DD 60.5% and 86.1% showed superior emulsifying activity and stability. Chitosan with low Mw exhibited better emulsifying activity than those with high Mw. Chitosan with Mw 410 kDa and 600 kDa showed superior emulsifying activity in the test range. Emulsifying stability of chitosan increased with a rise of Mw. PMID:21382402

Li, Xingke; Xia, Wenshui

2011-06-01

125

Design of protein-releasing chitosan channels.  

PubMed

After traumatic injury to the spinal cord, the neural tissue degenerates, resulting in lost function below the site of injury. Promoting axonal regeneration after injury remains a challenge; however, guidance channels have demonstrated some success when combined with cellular and protein therapies. One of the limitations of current guidance channels is the inability to deliver therapeutically relevant molecules in situ, within the guidance channel, to enhance regeneration. In an effort to provide a system for local and sustained drug release, poly(lactide-co-glycolide) (PLGA) microspheres were embedded into chitosan guidance channels by a novel spin-coating technique. The method was designed to create guidance channels with the appropriate dimensions for implantation into the spinal cord, with special attention paid to the wall thickness. The release and bioactivity of a model protein, alkaline phosphatase, was followed from the channels and compared to those from free-floating microspheres over a 90-day period. Since chitosan formulations often require the use of acidic solutions, careful attention was paid to redesign the process to minimize exposure of PLGA microspheres to acid. This was achieved as demonstrated by release and bioactivity data where alkaline phosphatase released from chitosan/microsphere channels followed a profile and bioactivity similar to those of free floating microspheres. PMID:18324828

Kim, Howard; Tator, Charles H; Shoichet, Molly S

2008-01-01

126

Hierarchical structure and physicochemical properties of plasticized chitosan.  

PubMed

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

Meng, Qingkai; Heuzey, Marie-Claude; Carreau, Pierre J

2014-04-14

127

Effects of chitosan particles in periodontal pathogens and gingival fibroblasts.  

PubMed

Chitosan is a naturally derived polymer with antimicrobial and anti-inflammatory properties. However, studies evaluating the role of chitosan in the control of periodontal pathogens and the responses of fibroblasts to inflammatory stimuli are lacking. In the present study, we analyzed whether chitosan particles may inhibit the growth of periodontal pathogens and modulate the inflammatory response in human gingival fibroblasts. Chitosan particles were generated through ionic gelation. They inhibited the growth of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans at 5 mg/mL. Conversely, IL-1? strongly stimulated PGE2 protein levels in gingival fibroblasts, and chitosan inhibited this response at 50 µg/mL. IL-1?-stimulated PGE2 production was dependent on the JNK pathway, and chitosan strongly inhibited this response. IL-1? stimulated NF-?B activation, another signaling pathway involved in PGE2 production. However, chitosan particles were unable to modify NF-?B signaling. The present study shows that chitosan exerts a predominantly anti-inflammatory activity by modulating PGE2 levels through the JNK pathway, which may be useful in the prevention or treatment of periodontal inflammation. PMID:23788611

Arancibia, R; Maturana, C; Silva, D; Tobar, N; Tapia, C; Salazar, J C; Martínez, J; Smith, P C

2013-08-01

128

Chitosan: A versatile biopolymer for orthopaedic tissue-engineering  

Microsoft Academic Search

Current tissue engineering strategies are focused on the restoration of pathologically altered tissue architecture by transplantation of cells in combination with supportive scaffolds and biomolecules. In recent years, considerable attention has been given to chitosan (CS)-based materials and their applications in the field of orthopedic tissue engineering. Interesting characteristics that render chitosan suitable for this purpose are a minimal foreign

Alberto Di Martino; Michael Sittinger; Makarand V. Risbud

2005-01-01

129

Chitosan as green kinetic inhibitors for gas hydrate formation  

Microsoft Academic Search

The kinetic inhibiting effect of a number of chitosans on hydrate formation was investigated using methane and methane\\/ethane gas mixtures. The results indicated that chitosan was a good kinetic inhibitor. The induction time of gas hydrate formation evidently increased with the degree of deacetylation (DD), however, when DD was higher than 80%, the effect of DD on the induction time

Yongjun Xu; Minlin Yang; Xiaoxi Yang

2010-01-01

130

Detection of chitosan in Scots pine by Energy Dispersive X-ray Spectroscopy  

Microsoft Academic Search

The aim of this study was to use Energy-Dispersive X-ray Spectroscopy (EDS) to localize chitosan in the cell wall of chitosan impregnated Scots pine. It is of both general and specific interest to investigate the concentration of chitosan in the wood matrix to gain further knowledge and understanding of chitosan as a wood protective system. After deacetylation, chitosan was re-acetylated

E. LARNØY; M. EIKENES; H. MILITZ

131

Dairy Wastewater Treatment Using Low Molecular Weight Crab Shell Chitosan  

NASA Astrophysics Data System (ADS)

The investigation of possible use of low molecular weight crab shell chitosan (MW 20 kDa) in the treatment of dairy waste water was studied. Various experiments have been carried out using batch adsorption technique to study the effects of the process variables, which include contact time, stirring speed, pH and adsorbent dosage. Treated effluent characteristics at optimum condition showed that chitosan can be effectively used as adsorbent in the treatment of dairy wastewater. The optimum conditions for this study were at 150 mg/l of chitosan, pH 5 and 50 min of mixing time with 50 rpm of mixing speed. Chitosan showed the highest performance under these conditions with 79 % COD, 93 % turbidity and 73 % TSS reduction. The result showed that chitosan is an effective coagulant, which can reduce the level of COD, TSS and turbidity in dairy industry wastewater.

Geetha Devi, M.; Dumaran, Joefel Jessica; Feroz, S.

2012-08-01

132

Antibacterial activity of polyacrylonitrile-chitosan electrospun nanofibers.  

PubMed

Polyacrylonitrile (PAN)-chitosan double-face films and nanofibers were manufactured. PAN and a chitosan salt were dissolved in dimethyl sulfoxide, and then thin-layered on a glass plate or electro-spun followed by coagulation in sodium hydroxide solution. The morphology of the PAN-chitosan double-face films and nanofibers was analyzed by scanning electron microscopy. The thermal behavior and the glass transition temperature of PAN-chitosan blends were assessed by differential scanning calorimetry and dynamic mechanical analysis, respectively. The antibacterial efficacy was measured by a swatch test with bacterial suspensions. The PAN-chitosan nanofibers produced a 5-log reduction against Escherichia coli, Staphylococcus aureus, and Micrococcus luteus. PMID:24507277

Kim, Sam Soo; Lee, Jaewoong

2014-02-15

133

Antimicrobial coating of modified chitosan onto cotton fabrics  

NASA Astrophysics Data System (ADS)

Chitosan has been applied as an antibacterial agent to provide biocidal function for textiles but has limitations of application condition and durability. In this study, a new N-halamine chitosan derivative was synthesized by introducing N-halamine hydantoin precursor. The synthesized chitosan derivative 1-Hydroxymethyl-5,5-dimethylhydantoin chitosan (chitosan-HDH) was coated onto cotton fabric with 1,2,3,4-butanetetracarboxylic acid (BTCA) as a crosslinking agent. The coatings were characterized and confirmed by FT-IR and SEM. The treated cotton fabrics can be rendered excellent antimicrobial activity upon exposure to dilute household bleach. The chlorinated coated swatches can inactivate 100% of the Staphylococcus aureus and E. coli O157:H7 with a contact time of 5 min. Almost all the lost chlorine after a month of storage could be recharged upon rechlorination. The crease recovery property of the treated swatches improved while the breaking strength decreased compared with uncoated cotton.

Cheng, Xiaoli; Ma, Kaikai; Li, Rong; Ren, Xuehong; Huang, T. S.

2014-08-01

134

Physiochemical and optical properties of chitosan based graphene oxide bionanocomposite.  

PubMed

In the present investigation an ecofriendly approach and a simple homogeneous solution casting method led to the development of biodegradable chitosan/graphene oxide bionanocomposites. The formation of bionanocomposite was confirmed by UV-vis, FT-IR, Raman spectroscopy, XRD, and further evaluated by thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The circular dichroism (CD) study of chitosan/graphene oxide revealed that the intensity of the negative transition band at wavelength of 200-222 nm decreased with the different pH of chitosan/graphene oxide solutions. It was also found that the pH conditions affect the interaction between chitosan and graphene oxide. Optical properties of chitosan/graphene oxide are evaluated by photoluminescence (PL) spectroscopy which showed blue shift at excitation wavelength of 255 nm compared to graphene oxide. These results strongly suggest that the bionanocomposite materials may open new vistas in biotechnological, biosensor and biomedical applications. PMID:25077836

Kumar, Santosh; Koh, Joonseok

2014-09-01

135

Characterization and bacterial adhesion of chitosan-perfluorinated acid films.  

PubMed

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

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

2014-02-01

136

A prototype of giant magnetoimpedance-based biosensing system for targeted detection of gastric cancer cells.  

PubMed

A targeted detection of gastric cancer cells is achieved by combining the giant magnetoimpedance (GMI)-based biosensing system and RGD-4C peptide coupled, chitosan covered superparamagnetic iron oxide particles (RGD-Fe(3)O(4)@chitosan). The micro-patterned GMI sensor for targeted detection is made of Co-based ribbon and fabricated by micro electromechanical system (MEMS) technology. Functionalized nanoparticles were designed by coating Fe(3)O(4) with chitosan and conjugating with RGD-4C peptides. The targeted cells were trickled down into the detection area of the system. The detection of each sample is carried out in ten-fold manner and average value is taken as the final result. This system can identify the differences between targeted cells and non-targeted cells. It is of considerable interest due to its potential application in the biomedical field of various specific detections. PMID:21239159

Chen, Lei; Bao, Chen-Chen; Yang, Hao; Li, Ding; Lei, Chong; Wang, Tao; Hu, Heng-Yao; He, Meng; Zhou, Yong; Cui, Da-Xiang

2011-03-15

137

Optimization of chitosan succinate and chitosan phthalate microspheres for oral delivery of insulin using response surface methodology.  

PubMed

In the present study, a Box-Behnken experimental design was employed to statistically optimize the formulation parameters of chitosan phthalate and chitosan succinate microspheres preparation. These microspheres can be useful for oral insulin delivery system. The effects of three parameters namely polymer concentration, stirring speed and cross linking agent were studied. The fitted mathematical model allowed us to plot response surfaces curves and to determine optimal preparation conditions. Results clearly indicated that the crosslinking agent was the main factor influencing the insulin loading and releasing. The in vitro results indicated that chitosan succinate microspheres need high amount of crosslinking agent to control initial burst release compared to chitosan phthalate microspheres. The reason may be attributed that chitosan succinate is more hydrophilic than chitosan phthalate. The relative pharmacological efficacy for chitosan phthalate and chitosan succinate microspheres (18.66 +/- 3.84%, 16.24 +/- 4%) was almost three-fold higher than the efficacy of the oral insulin administration (4.68 +/- 1.52%). These findings suggest that these microspheres are promising carrier for oral insulin delivery system. PMID:18821127

Ubaidulla, Udhumansha; Khar, R K; Ahmad, F J; Tripathi, Purnima

2009-01-01

138

Chitosan removes toxic heavy metal ions from cigarette mainstream smoke  

NASA Astrophysics Data System (ADS)

This study investigated the removal of heavy metal ions from cigarette mainstream smoke using chitosan. Chitosan of various deacetylation degrees and molecular weights were manually added to cigarette filters in different dosages. The mainstream smoke particulate matter was collected by a Cambridge filter pad, digested by a microwave digestor, and then analyzed for contents of heavy metal ions, including As(III/V), Pb(II), Cd(II), Cr(III/VI) and Ni(II), by graphite furnace atomic absorption spectrometry (GFAAS). The results showed that chitosan had a removal effect on Pb(II), Cd(II), Cr(III/VI) and Ni(II). Of these, the percent removal of Ni(II) was elevated with an increasing dosage of chitosan. Chitosan of a high deace tylation degree exhibited good binding performance toward Cd(II), Cr(III/VI) and Ni(II), though with poor efficiency for Pb(II). Except As(III/V), all the tested metal ions showed similar tendencies in the growing contents with an increasing chitosan molecular weight. Nonetheless, the percent removal of Cr(III/VI) peaked with a chitosan molecular weight of 200 kDa, followed by a dramatic decrease with an increasing chitosan molecular weight. Generally, chitosan had different removal effects on four out of five tested metal ions, and the percent removal of Cd(II), Pb(II), Cr(III/VI) and Ni(II) was approximately 55%, 45%, 50%, and 16%, respectively. In a word, chitosan used in cigarette filter can remove toxic heavy metal ions in the mainstream smoke, improve cigarette safety, and reduce the harm to smokers.

Zhou, Wen; Xu, Ying; Wang, Dongfeng; Zhou, Shilu

2013-09-01

139

Thiolated chitosan nanoparticles as a delivery system for antisense therapy: evaluation against EGFR in T47D breast cancer cells  

PubMed Central

Thiolated chitosan has high transfection and mucoadhesive properties. We investigated the potential of two recently synthesized polymers: NAC-C (N-acetyl cysteine-chitosan) and NAP-C (N-acetyl penicillamine-chitosan) in anticancer drug delivery targeting epidermal growth factor receptor (EGFR). Doxorubicin (DOX) and antisense oligonucleotide (ASOND)-loaded polymer nanoparticles were prepared in water by a gelation process. Particle characterization, drug loading, and drug release were evaluated. To verify drug delivery efficiency in vitro experiments on a breast cancer cell line (T47D) were performed. EGFR gene and protein expression was analyzed by real time quantitative polymerase chain reaction and Western blotting, respectively. A loading percentage of 63% ± 5% for ASOND and 70% ± 5% for DOX was achieved. Drug release data after 15 hours showed that ASOND and DOX were completely released from chitosan-based particles while a lower and more sustained release of only 22% ± 8% was measured for thiolated particles. In a cytosol simulated release medium/reducing environment, such as found intracellularly, polymer-based nanoparticles dissociated, liberating approximately 50% of both active substances within 7 hours. ASOND-loaded polymer nanoparticles had higher stability and high mucoadhesive properties. The ASOND-loaded thiolated particles significantly suppressed EGFR gene expression in T47D cells compared with ASOND-loaded chitosan particles and downregulated EGFR protein expression in cells. This study could facilitate future investigations into the functionality of NAP-C and NAC-C polymers as an efficient ASOND delivery system in vitro and in vivo. PMID:21976973

Talaei, Fatemeh; Azizi, Ebrahim; Dinarvand, Rassoul; Atyabi, Fatemeh

2011-01-01

140

Ionization and Solubility of Chitosan Solutions Related to Thermosensitive Chitosan/Glycerol-Phosphate Systems  

E-print Network

monomers) in chitosan. In the current study we performed temperature-controlled titration and dilution performed during titration to indicate precipitation. We found the apparent proton dissociation constant cationic polyelectrolyte derived by alkaline deacetylation of chitin in crustacean shells1 and is composed

Buschmann, Michael

141

Impact of the structural differences between ?- and ?-chitosan on their depolymerizing reaction and antibacterial activity.  

PubMed

The polymeric structure characteristics of ?-chitosan from jumbo squid (Dosidicus gigas) pens and ?-chitosan from shrimp shells during depolymerization by cellulase hydrolysis at different degrees of deacetylation (DDA) (60, 75, and 90%) were investigated by using Fourier transform infrared spectroscopy and X-ray diffraction. Antibacterial activity of ?-chitosan against Escherichia coli and Listeria innocua was compared with that of ?-chitosan at similar Mw and degrees of deacetylation (DDA) by studying inhibition ratio and minimal inhibition concentration (MIC) and was coordinated with the structural characteristics of the two forms of chitosan. ?-Chitosan was more reactive to cellulase hydrolysis than ?-chitosan due to its relatively lower crystallinity (CI) and loose crystal property, and the 75% DDA chitosan was more susceptible to cellulase than the 90% DDA ones with the 75% DDA of ?-chitosan mostly reactive. Both forms of chitosan showed more inhibition against E. coli than against L. innocua, and no difference against L. innocua between the two forms of chitosan was observed. However, the two forms of chitosan exhibited different levels of antibacterial activity against E. coli, in which 75% DDA/31 kDa ?-chitosan demonstrated significantly higher inhibition (lower MIC) than that of 75% DDA/31 kDa ?-chitosan, whereas 90% DDA/74-76 kDa ?-chitosan had a higher inhibition ratio than that of 90% DDA/74-76 kDa of ?-chitosan. This result may be explained by the impact of the different structural properties between ?- and ?-chitosan on chitosan conformations in the solution. This study provided new information about the biological activities of ?-chitosan, a bioactive compound with unique functionalities and great potential for food and other applications. PMID:23909640

Jung, Jooyeoun; Zhao, Yanyun

2013-09-18

142

Comparative studies on polyelectrolyte complexes and mixtures of chitosan–alginate and chitosan–carrageenan as prolonged diltiazem clorhydrate release systems  

Microsoft Academic Search

The aim of this work was to evaluate the possibility of using mixtures and\\/or polyelectrolyte complexes from both chitosan-alginate and chitosan–carrageenan as prolonged drug release systems. Different dissolution profiles were obtained by changing the polymer matrix system (chitosan–alginate or chitosan–carrageenan) and the method used to include these polymers into the formulation (physical mixture or polyelectrolyte complex). Drug dissolution profiles from

Cristián Tapia; Zunilda Escobar; Edda Costa; Jaime Sapag-Hagar; Fernando Valenzuela; Carlos Basualto; Mar??a Nella Gai; Mehrdad Yazdani-Pedram

2004-01-01

143

Synthesis and Evaluation of Chitosan-Vitamin C complex.  

PubMed

Chitosan is a biocompatible, biodegradable and non-toxic polysaccharide polymer. It dissolves in water only if the pH is lower than 6.5. To extend its range of application, many water-soluble derivatives have therefore been prepared. In this research, chitosan-vitamin C complex was synthesized and characterized with Fourier transformed infrared spectroscopy, differential scanning calorimetry and (1)H-NMR. The solubility of chitosan-vitamin C complex in distilled water was greatly improved. The *O(2) (-) scavenging activity of chitosan-vitamin C complex was compared with chitosan and vitamin C by measuring the auto-oxidation rate of pyrogallic acid. Results showed that the scavenging activity on *O(2) (-) by chitosan-vitamin C complex was stronger than that by CS. At low concentrations (< 0.05 mg/ml), the scavenging activity of chitosan-vitamin C complex was stronger than that of vitamin C, but after certain concentrations (>0.1mg/ml), its scavenging activity was lower than that of vitamin C. PMID:20502541

Tian, X L; Tian, D F; Wang, Z Y; Mo, F K

2009-07-01

144

Mechanism of arsenic removal using chitosan and nanochitosan.  

PubMed

Chitosan, a natural polysaccharide copolymer of glucosamine and N-acetyl-glucosamine, possesses one free primary amine and two free hydroxyl groups on each glucosamine unit. It has a polycationic nature and an abundance of amine functional groups. The sorption equilibrium and kinetics of arsenate onto chitosan flakes have been studied. The effect of pH on the adsorption capacity and the uptake kinetics is an important parameter to investigate the adsorption mechanism of anionic species such as arsenate ions on the protonated amine groups of chitosan. The equilibrium sorption and batch kinetic studies of arsenate ions on chitosan were performed at initial As concentration of 250-11,000 ?g L(-1) and initial pH ranging from pH=3.50-5.50. The experimental results showed that initially for approximately the first 30 min there is a rapid and high adsorption of arsenate ions onto the chitosan leading to a maximum uptake capacity after this short time. However, this stage is followed by a slow desorption of arsenate from the chitosan with a steady increase in solution pH. A novel reversible pseudo-first order kinetic model was developed and applied to correlate this newly reported adsorption-desorption phenomenon. The physical and chemical properties of chitosan were studied and presented in terms of its surface and structural properties such as the degree of deacetylation, crystallinity, surface charge and its swelling properties. PMID:24370394

Kwok, Katrina C M; Koong, Len Foong; Chen, Guohua; McKay, Gordon

2014-02-15

145

Transglutaminase-catalyzed grafting collagen on chitosan and its characterization.  

PubMed

Collagen grafted chitosan was prepared with microbial transglutaminase (MTGase) as biocatalyst which showed high efficiency, selectivity, mild reaction condition and environmental friendliness. The reaction conditions that influenced the degree of substitution (DS) were optimized, which included the reaction time, the reaction temperature, the mass ratio of collagen to chitosan and the mass ratio of MTGase to chitosan. In this study, the water-solubility collagen-chitosan could serve not only to reduce the loss of moisture but also to absorb the moisture. And the moisture absorption and moisture retention abilities were closely related to the DS values. In addition, in vitro antioxidant activity was evaluated in terms of DS values and concentration. Furthermore, L929 mouse fibroblasts were cultured with collagen-chitosan, and methylthiazol tetrazolium (MTT) assay exhibited that collagen-chitosan with DS of 0.660 displayed pronounced cell viability at 2.5mg/ml. Therefore, the water-soluble collagen-chitosan showed the potentiality to repair skin in cosmetic, biomedical and pharmaceutical fields. PMID:24708978

Fan, Lihong; Wu, Huan; Zhou, Xiaoyu; Peng, Min; Tong, Jun; Xie, Weiguo; Liu, Shuhua

2014-05-25

146

Functional gene silencing mediated by chitosan/siRNA nanocomplexes  

NASA Astrophysics Data System (ADS)

Chitosan/siRNA nanoparticles to knock down FHL2 gene expression were reported in this work. The physicochemical properties such as particle size, surface charge, morphology and complex stability of chitosan nanoparticle-incorporated siRNA were evaluated. Nanoparticles which were formulated with chitosan/siRNA exhibited irregular, lamellar and dendritic structures with a hydrodynamic radius size of about 148 nm and net positive charges with zeta-potential value of 58.5 mV. The knockdown effect of the chitosan/siRNA nanoparticles on gene expression in FHL2 over-expressed human colorectal cancer Lovo cells was investigated. The result showed that FHL2 siRNA formulated within chitosan nanoparticles could knock down about 69.6% FHL2 gene expression, which is very similar to the 68.8% reduced gene expression when siRNA was transfected with liposome Lipofectamine. Western analysis further showed significant FHL-2 protein expression reduced by the chitosan/siRNA nanoparticles. The results also showed that blocking FHL2 expression by siRNA could also inhibit the growth and proliferation of human colorectal cancer Lovo cells. The current results demonstrated that chitosan-based siRNA nanoparticles were a very efficient delivery system for siRNA in vivo as previously reported.

Ji, A. M.; Su, D.; Che, O.; Li, W. S.; Sun, L.; Zhang, Z. Y.; Yang, B.; Xu, F.

2009-10-01

147

Electrolytic deposition of calcium phosphate\\/chitosan coating on titanium alloy: Growth kinetics and influence of current density, acetic acid, and chitosan  

Microsoft Academic Search

Electrolytically deposited calcium phosphate\\/chitosan coating demonstrated good bone marrow stromal cell attachment. The aim of this study was to understand the coating's growth kinetics as well as the effects of current density, acetic acid, and chitosan on the coating's formation. The scanning electron micrographs found that calcium phosphate crystals homogeneously distributed into chitosan aggregates as early as 30 min. X-ray

Jiawei Wang; Apeldoorn van Aart; Groot de Klaas

2006-01-01

148

Development of polycaprolactone/chitosan blend porous scaffolds.  

PubMed

Polycaprolactone (PCL) and chitosan were blended to fabricate porous scaffolds for tissue-engineering applications by employing a concentrated acetic acid solution as solvent and salt particles as porogen. These scaffolds showed well-controlled and interconnected porous structures. The pore size and porosity of the scaffolds could be effectively modulated by selecting appropriate amounts and sizes of porogen. The results obtained from compressive mechanical measurements indicated that PCL/chitosan could basically retain their strength in their dry state compared to individual components. In a hydrated state, their compressive stress and modulus could be still well maintained even though the weight ratio of chitosan reached around 50 wt%. PMID:18987952

Wan, Ying; Xiao, Bo; Dalai, Siqin; Cao, Xiaoying; Wu, Quan

2009-03-01

149

Production and isolation of chitosan from Mucor rouxii.  

PubMed Central

A method for the lab-scale production and isolation of chitosan (polyglucosamine) from hyphal walls of Mucor rouxii was developed. Hyphal wall yields were generally 16 to 22% on a dry cell weight basis, of which 35 to 40% was glucosamine. Chitosan was readily extracted from purified, mycelial walls with acetic, formic, and hydrochloric acids; the last named was the most efficient. The yield of chitosan isolated ranged from 4 to 8% of the dry weight of the cell wall material. Images PMID:518086

White, S A; Farina, P R; Fulton, I

1979-01-01

150

Development and in vitro evaluation of novel floating chitosan microcapsules for oral use: comparison with non-floating chitosan microspheres.  

PubMed

Floating (F) microcapsules containing melatonin (MT) were prepared by the ionic interaction of chitosan and a negatively charged surfactant, sodium dioctyl sulfosuccinate (DOS). The DOS/chitosan complex formation was confirmed employing infrared spectroscopy, differential scanning calorimetry (DSC), solubility and X-ray diffraction analysis. The characteristics of the F microcapsules generated compared with the conventional non-floating (NF) microspheres manufactured from chitosan and sodium tripolyphosphate (TPP) were also investigated. The effect of various factors (crosslinking time, DOS and chitosan concentrations, as well as drug/polymer ratio) on microcapsule properties were evaluated. The use of DOS solution in coagulation of chitosan produced well-formed microcapsules with round hollow core and 31.2-59.74% incorporation efficiencies. Chitosan concentration and drug/polymer ratio had a remarkable effect on drug entrapment in DOS/chitosan microcapsules. The dissolution profiles of most of microcapsules showed near zero order kinetics in simulated gastric fluid (S.G.F: pH 1.2). Moreover, release of the drug from these microcapsules was greatly retarded with release lasting for several hours (t(50%) (S.G.F.): 1.75-6.7 h, depending on processing factors), compared with NF microspheres where drug release was almost instant. Most of the hollow microcapsules developed tended to float over simulated biofluids for more than 12 h. Swelling studies conducted on various drug-free formulations, clearly indicated that DOS/chitosan microcapsules showed less swelling and no dissolution in S.G.F. for more than 3 days, whereas, TPP/chitosan microspheres were markedly swollen and lost their integrity in S.G.F. within 5 h. Therefore, data obtained suggest that the F hollow microcapsules produced would be an interesting gastroretentive controlled-release delivery system for drugs. PMID:12433430

El-Gibaly, Ibrahim

2002-12-01

151

Inactivation of heparin by cationically modified chitosan.  

PubMed

This study was performed to evaluate the ability of N-(2-hydroxypropyl)-3-tri methylammonium chitosan chloride (HTCC), the cationically modified chitosan, to form biologically inactive complexes with unfractionated heparin and thereby blocking its anticoagulant activity. Experiments were carried out in rats in vivo and in vitro using the activated partial thromboplastin time (APTT) and prothrombin time (PT) tests for evaluation of heparin anticoagulant activity. For the first time we have found that HTCC effectively neutralizes anticoagulant action of heparin in rat blood in vitro as well as in rats in vivo. The effect of HTCC on suppression of heparin activity is dose-dependent and its efficacy can be comparable to that of protamine-the only agent used in clinic for heparin neutralization. HTCC administered i.v. alone had no direct effect on any of the coagulation tests used. The potential adverse effects of HTCC were further explored using rat experimental model of acute toxicity. When administered i.p. at high doses (250 and 500 mg/kg body weight), HTCC induced some significant dose-dependent structural abnormalities in the liver. However, when HTCC was administered at low doses, comparable to those used for neutralization of anticoagulant effect of heparin, no histopathological abnormalities in liver were observed. PMID:24983639

Lorkowska-Zawicka, Barbara; Kami?ski, Kamil; Ciejka, Justyna; Szczubia?ka, Krzysztof; Bia?as, Magdalena; Oko?, Krzysztof; Adamek, Dariusz; Nowakowska, Maria; Jawie?, Jacek; Olszanecki, Rafa?; Korbut, Ryszard

2014-07-01

152

Fabrication of biocompatible and mechanically reinforced graphene oxide-chitosan nanocomposite films  

PubMed Central

Background Graphene oxide (GO)can be dispersed through functionalization, or chemically converted to make different graphene-based nanocomposites with excellent mechanical and thermal properties. Chitosan, a partially deacetylated derivative of chitin, is extensively used for food packaging, biosensors, water treatment, and drug delivery. GO can be evenly dispersed in chitosan matrix through the formation of amide linkages between them, which is different from previous reports focusing on preparing GO/chitosan nanocomposites through physical mixing. Results In this study, free-standing graphene oxide-chitosan (GO-chitosan) nanocomposite films have been prepared. The GO-chitosan films are biologically compatible and mechanically reinforced. Through the formation of amide linkages between GO’s carboxylic acid groups and chitosan's amine groups, GO could be evenly dispersed within the chitosan matrix. We also characterized the GO-chitosan composite films using element analysis, Fourier transform infrared spectroscopy, X-ray photo electron spectroscopy, differential scanning calorimetry, and thermo gravimetric analysis. Compared to pristine chitosan film, the tensile strength of GO-chitosan film is improved by 2.5 folds and Young’s modulus increases by nearly 4.6 folds. The glass transition temperature of GO-chitosan composite film shifts from 118°C to 158°C compared to the pristine chitosan, indicating its enhanced thermal stability. GO-chitosan composite film was also evaluated for its biocompatibility with C3H10T1/2 cells by in vitro fluorescent staining. The graphene oxide-reinforced chitosan composite films could have applications in functional biomaterials. Conclusion The present study describes a useful and simple method to chemically attach biocompatible chitosan onto graphene oxide. We envision that the GO-chitosan film will open avenues for next-generation graphene applications in the realm of functional biomaterial. PMID:23442350

2013-01-01

153

Free radical mediated grafting of chitosan with caffeic and ferulic acids: structures and antioxidant activity.  

PubMed

In this study, two water soluble chitosan derivatives were synthesized by grafting caffeic acid (CA) and ferulic acid (FA) onto chitosan via a free radical mediated method. The structural characterization, antioxidant activity in vitro and in vivo of chitosan derivatives were determined. Results showed that the UV-vis absorption peaks of chitosan derivatives shifted toward longer wavelengths. FT-IR spectroscopy exhibited the typical phenolic characteristics within 1450-1600 cm(-1). (1)H NMR spectroscopy showed new peaks of phenyl protons at 6.2-7.6 ppm. (13)C NMR spectroscopy showed additional peaks between 110 and 150 ppm assigned to the C=C of phenolic groups. These results all confirmed the successful grafting of CA and FA onto chitosan backbones. The chitosan derivatives had decreased thermal stability and crystallinity as compared to chitosan. In vitro assays showed that the antioxidant activity decreased in the order of CA-g-chitosan>FA-g-chitosan>chitosan. Moreover, administration of the chitosan derivatives could significantly increase antioxidant enzymes activities and decrease malondialdehyde levels in both serums and livers of d-galactose induced aging mice. Our results indicated the potential of CA-g-chitosan and FA-g-chitosan in the development of novel antioxidant agents. PMID:24444883

Liu, Jun; Wen, Xiao-yuan; Lu, Jian-feng; Kan, Juan; Jin, Chang-hai

2014-04-01

154

Hematotoxicological analysis of surface-modified and -unmodified chitosan nanoparticles.  

PubMed

The increasing interest in using chitosan nanoparticles for controlled drug delivery is hampered by its blood incompatibility, especially for intravenous applications. This study investigated the effects of processing solvents (acetic acid/lactic acid), dispersing media (acidic medium/saline), and surface modifiers (polyethylene glycol, polyvinyl alcohol, and ethylenediaminetetraacetatic acid) on the hemocompatibility of chitosan. Blood compatibility of chitosan nanoparticles prepared by ionotropic gelation with altered surface chemistry was evaluated by assessing their hemolytic activity, platelet aggregation, coagulation, and cytokine induction. It was observed that nanoparticles prepared in lactic acid and dispersed in saline did not show hemolysis, platelet aggregation, or coagulation, whereas nanoparticles prepared in acetic acid showed strong hemolysis. Surface modifiers were not observed to significantly affect blood compatibility, with the exception of EDTA, which delayed blood clotting times. Thus, chitosan nanoparticles prepared in lactic acid and dispersed in saline may be an ideal nanocarrier for parenteral applications. PMID:23613460

Nadesh, Ragima; Narayanan, Dhanya; P R, Sreerekha; Vadakumpully, Sajini; Mony, Ullas; Koyakkutty, Manzoor; Nair, Shantikumar V; Menon, Deepthy

2013-10-01

155

Microstructure and Properties of Polyhydroxybutyrate-Chitosan-Nanohydroxyapatite Composite Scaffolds  

PubMed Central

Polyhydroxybutyrate-chitosan-hydroxyapatite (PHB-CHT-HAP) composite scaffolds were prepared by the precipitation of biopolymer-nanohydroxyapatite suspensions and following lyophilisation. The propylene carbonate and acetic acid were used as the polyhydroxybutyrate and chitosan solvents, respectively. The high porous microstructure was observed in composites and the macroporosity of scaffolds (pore sizes up to 100??m) rose with the chitosan content. It was found the reduction in both the PHB melting (70°C) and thermal degradation temperatures of polyhydroxybutyrate and chitosan biopolymers in composites, which confirms the mutual ineraction between polymers and the decrease of PHB lamellar thickness. No preferential preconcentration of individual biopolymers was verified in composites, and the compressive strengths of macroporous PHB-CHT-HAP scaffolds were approximately 2.5?MPa. The high toxic fluorinated cosolvents were avoided from the preparation process. PMID:22547987

Medvecky, L.

2012-01-01

156

Development of chitosan-based antimicrobial leather coatings.  

PubMed

The development of antimicrobial coatings for footwear components is of great interest both from industry and consumer's point of view. In this work, antimicrobial leather materials were developed taking advantage of chitosan intrinsic antimicrobial activity and film forming capacity. Considering the specificities of the leather tanning industry, different coating technologies, namely drum, calender and spray, were tested, being the best results achieved with the drum. This last approach was further investigated to assess the effect of chitosan content, type of solubilizing acid, and impregnation time on the achieved antimicrobial capacity. Considering chitosan price (economic reasons) and the obtained results (antimicrobial activity and coating effectiveness, as inspected by SEM), the impregnation in the drum using a chitosan content of 1% (w/v) in a formic acid solution during 2h, is proposed as the best option for obtaining leather with antimicrobial capacity. PMID:23987468

Fernandes, Isabel P; Amaral, Joana S; Pinto, Vera; Ferreira, Maria José; Barreiro, Maria Filomena

2013-10-15

157

Chitosan Based Film Electrolytes Doped Oleic Acid: An Electrical Study  

NASA Astrophysics Data System (ADS)

1g chitosan was dissolved in l00 mL of 1% acetic acid solution to prepare a chitosan acetate solution. The solution was then mixed with oleic acid. This chitosan acetate-oleic acid was then made into thin film by the solution cast technique. The conductivity of the samples was measured from ambient to elevated temperature. The highest conductivity of the chitosan-salt with 10 wt % oleic acid (OA) at room temperature was 8.35×10-9 Scm-1. The addition of OA has increased the dielectric constant, which implies the increase of dissociation of the salt thereby producing more free ions for conducting and hence increases the ionic conductivity.

Idris, Nor Kartini; Aziz, N. A. Nik; Ramli, S.; Isa, M. Ikmar Nizam

2008-05-01

158

Advances in self-assembled chitosan nanomaterials for drug delivery.  

PubMed

Nanomaterials based on chitosan have emerged as promising carriers of therapeutic agents for drug delivery due to good biocompatibility, biodegradability, and low toxicity. Chitosan originated nanocarriers have been prepared by mini-emulsion, chemical or ionic gelation, coacervation/precipitation, and spray-drying methods. As alternatives to these traditional fabrication methods, self-assembled chitosan nanomaterials show significant advantages and have received growing scientific attention in recent years. Self-assembly is a spontaneous process by which organized structures with particular functions and properties could be obtained without additional complicated processing or modification steps. In this review, we focus on recent progress in the design, fabrication and physicochemical aspects of chitosan-based self-assembled nanomaterials. Their applications in drug delivery of different therapeutic agents are also discussed in details. PMID:25109677

Yang, Yu; Wang, Shengpeng; Wang, Yitao; Wang, Xiaohui; Wang, Qun; Chen, Meiwan

2014-11-15

159

Comprehensive characterization of chitosan/PEO/levan ternary blend films.  

PubMed

Ternary blend films of chitosan, PEO (300,000) and levan were prepared by solution casting method and their phase behavior, miscibility, thermal and mechanical properties as well as their surface energy and morphology were characterized by different techniques. FT-IR analyses of blend films indicated intermolecular hydrogen bonding between blend components. Thermal and XRD analysis showed that chitosan and levan suppressed the crystallinity of PEO up to nearly 25% of PEO content in the blend, which resulted in more amorphous film structures at higher PEO/(chitosan+levan) ratios. At more than 30% of PEO concentration, contact angle (CA) measurements showed a surface enrichment of PEO whereas at lower PEO concentrations, chitosan and levan were enriched on the surfaces leading to more amorphous and homogenous surfaces. This result was further confirmed by atomic force microscopy (AFM) images. Cell proliferation and viability assay established the high biocompatibility of the blend films. PMID:24507374

Bostan, Muge Sennaroglu; Mutlu, Esra Cansever; Kazak, Hande; Sinan Keskin, S; Oner, Ebru Toksoy; Eroglu, Mehmet S

2014-02-15

160

S-protected thiolated chitosan: synthesis and in vitro characterization.  

PubMed

Purpose of the present study was the generation and evaluation of novel thiolated chitosans, so-named S-protected thiolated chitosans as mucosal drug delivery systems. Stability of all conjugates concerning swelling and disintegration behavior as well as drug release was examined. Mucoadhesive properties were evaluated in vitro on intestinal mucosa. Different thiolated chitosans were generated displaying increasing amounts of attached free thiol groups on the polymer, whereby more than 50% of these thiol groups were linked with 6-mercaptonicotinamide. Based on the implementation of this hydrophobic residue, the swelling behavior was 2-fold decreased, whereas stability was essentially improved. Their mucoadhesive properties were 2- and 14-fold increased compared to corresponding thiolated and unmodified chitosans, respectively. Release studies out of matrix tablets comprising the novel conjugates revealed a controlled release of a model peptide. Accordingly, S-protected thiomers represent a promising type of mucoadhesive polymers for the development of various mucosal drug delivery systems. PMID:22839999

Dünnhaupt, Sarah; Barthelmes, Jan; Thurner, Clemens C; Waldner, Claudia; Sakloetsakun, Duangkamon; Bernkop-Schnürch, Andreas

2012-10-01

161

S-protected thiolated chitosan: Synthesis and in vitro characterization  

PubMed Central

Purpose of the present study was the generation and evaluation of novel thiolated chitosans, so-named S-protected thiolated chitosans as mucosal drug delivery systems. Stability of all conjugates concerning swelling and disintegration behavior as well as drug release was examined. Mucoadhesive properties were evaluated in vitro on intestinal mucosa. Different thiolated chitosans were generated displaying increasing amounts of attached free thiol groups on the polymer, whereby more than 50% of these thiol groups were linked with 6-mercaptonicotinamide. Based on the implementation of this hydrophobic residue, the swelling behavior was 2-fold decreased, whereas stability was essentially improved. Their mucoadhesive properties were 2- and 14-fold increased compared to corresponding thiolated and unmodified chitosans, respectively. Release studies out of matrix tablets comprising the novel conjugates revealed a controlled release of a model peptide. Accordingly, S-protected thiomers represent a promising type of mucoadhesive polymers for the development of various mucosal drug delivery systems. PMID:22839999

Dunnhaupt, Sarah; Barthelmes, Jan; Thurner, Clemens C.; Waldner, Claudia; Sakloetsakun, Duangkamon; Bernkop-Schnurch, Andreas

2012-01-01

162

Effect of chitosan on Salmonella Typhimurium in broiler chickens.  

PubMed

Public concern with the incidence of antibiotic-resistant bacteria, particularly among foodborne pathogens such as Salmonella, has been challenging the poultry industry to find alternative means of control. The purposes of the present study were to evaluate in vitro and in vivo effects of chitosan on Salmonella enterica serovar Typhimurium (ST) infection in broiler chicks. For in vitro crop assay experiments, tubes containing feed, water, and ST were treated with either saline as a control or 0.2% chitosan. The entire assay was repeated in three trials. In two independent in vivo trials, 40 broiler chicks were assigned to an untreated control diet or dietary treatment with 0.2% chitosan for 7 days (20 broiler chicks/treatment). At day 4, chicks were challenged with 2×10? colony-forming units (CFU) ST/bird. In a third in vivo trial, 100 broiler chicks were assigned to untreated control diet or dietary treatment with 0.2% chitosan for 10 days (50 broiler chicks/treatment) to evaluate ST horizontal transmission. At day 3, 10 birds were challenged with 10? CFU ST/bird, and the remaining nonchallenged birds (n=40) were kept in the same floor pen. In all three in vitro trials, 0.2% chitosan significantly reduced total CFU of ST at 0.5 and 6?h postinoculation compared with control (p<0.05). In two in vivo trials, at 7 days, dietary 0.2% chitosan significantly reduced total CFU of recovered ST in the ceca in both experiments. Dietary 0.2% chitosan significantly reduced total ST CFU recovered in the ceca of horizontally challenged birds in the third in vivo trial. Chitosan at 0.2% significantly reduced the CFU of recovered ST in vitro and in vivo, proving to be an alternative tool to reduce crop, ceca, and consequently carcass ST contamination as well as decreasing the amount of ST shed to the environment. PMID:24237042

Menconi, Anita; Pumford, Neil R; Morgan, Marion J; Bielke, Lisa R; Kallapura, Gopala; Latorre, Juan D; Wolfenden, Amanda D; Hernandez-Velasco, Xochitl; Hargis, Billy M; Tellez, Guillermo

2014-02-01

163

Immobilization of anaerobic sludge using chitosan crosslinked with lignosulfonate  

Microsoft Academic Search

  A new method for immobilization of anaerobic sludge in chitosan is described. It is based on the reaction of basic NH2 groups of chitosan with the acidic sulfonic-groups of lignosulfonate to form sulfonilamide linkages. The new procedure features\\u000a simplicity, low-cost and mild immobilization conditions. Batch tests of acetate consumption along with a continuous reactor\\u000a operation confirmed the effectiveness of the

B Tartakovsky; L Petti; J Hawari; S R Guiot

1998-01-01

164

Atomic force microscopy of gastric mucin and chitosan mucoadhesive systems  

Microsoft Academic Search

Atomic force microscopy has been utilized to probe, at a molecular level, the interaction between purified pig gastric mucin (PGM) and a mucoadhesive cationic polymer, chitosan (sea cure 210›), with a low degree (approx. 11%) of acetylation. Images were produced detailing the structures of both PGM and chitosan in 0.1 M acetate buer (pH 4.5), followed by the complex of

Matthew P. DEACON; Simon MCGURK; Clive J. ROBERTS; Phillip M. WILLIAMS; Saul J. B. TENDLER; Martyn C. DAVIES; Stephen E. HARDING

2000-01-01

165

Investigation of chitosan–phenolics systems as wood adhesives  

Microsoft Academic Search

Chitosan–phenolics systems were investigated as wood adhesives. Adhesion between two pieces of wood veneer developed only when all three components—chitosan, a phenolic compound, and laccase—were present. For the adhesive systems containing a phenolic compound with only one phenolic hydroxyl group, adhesive strengths were highly dependent upon the chemical structures of phenolic compounds used in the system and the relative oxidation

Svetlana Peshkova; Kaichang Li

2003-01-01

166

Flocculation of kaolinite suspensions in water by chitosan  

Microsoft Academic Search

Flocculation of kaolinite suspensions in water using chitosan was studied in the pH range 5–9 and the turbidity ranging from 10 to 160 NTU. Chitosan, in presence of trace quantities of a substance present in aqueous soil extracts, effectively reduces turbidity due to kaolinite by flocculation and settling. Flocculation efficiency is very sensitive to pH, and reaches a maximum at

Ravi Divakaran; V. N Sivasankara Pillai

2001-01-01

167

Kinetics of cadmium uptake by chitosan-based crab shells  

Microsoft Academic Search

Crushed crab shells were chemically treated to transform the chitin present into chitosan. Three particle sizes with average diameters of 0.65, 1.43 and 3.38mm, average pore diameters ranging from ?300 to 540Å, and a specific surface area of ?30m2\\/g were obtained. Batch experiments were performed to study the uptake equilibrium and kinetics of cadmium by chitosan. Adsorption equilibrium followed a

Johanna R Evans; William G Davids; Jean D MacRae; Aria Amirbahman

2002-01-01

168

Chitin and Chitosan: Functional Biopolymers from Marine Crustaceans  

Microsoft Academic Search

Chitin and chitosan, typical marine polysaccharides as well as abundant biomass resources, are attracting a great deal of\\u000a attention because of their distinctive biological and physicochemical characteristics. To fully explore the high potential\\u000a of these specialty biopolymers, basic and application researches are being made extensively. This review deals with the fundamental\\u000a aspects of chitin and chitosan such as the preparation

Keisuke Kurita

2006-01-01

169

Chitosan–chondroitin sulfate and chitosan–hyaluronate polyelectrolyte complexes: biological properties  

Microsoft Academic Search

In this work, we compare some biological properties of a highly deacetylated chitosan to those obtained with the materials made from its polyelectrolyte complexes with various GAG’s such as chondroitin-sulfates and hyaluronic acid. The hydrolysis of the complexes by means of the specific hydrolytic enzymes is studied. Cell-adhesion and cell-proliferation on these materials is compared to that obtained with a

Anne Denuziere; Danielle Ferrier; Odile Damour; Alain Domard

1998-01-01

170

Chitosan Composites for Bone Tissue Engineering--An Overview  

PubMed Central

Bone contains considerable amounts of minerals and proteins. Hydroxyapatite [Ca10(PO4)6(OH)2] is one of the most stable forms of calcium phosphate and it occurs in bones as major component (60 to 65%), along with other materials including collagen, chondroitin sulfate, keratin sulfate and lipids. In recent years, significant progress has been made in organ transplantation, surgical reconstruction and the use of artificial protheses to treat the loss or failure of an organ or bone tissue. Chitosan has played a major role in bone tissue engineering over the last two decades, being a natural polymer obtained from chitin, which forms a major component of crustacean exoskeleton. In recent years, considerable attention has been given to chitosan composite materials and their applications in the field of bone tissue engineering due to its minimal foreign body reactions, an intrinsic antibacterial nature, biocompatibility, biodegradability, and the ability to be molded into various geometries and forms such as porous structures, suitable for cell ingrowth and osteoconduction. The composite of chitosan including hydroxyapatite is very popular because of the biodegradability and biocompatibility in nature. Recently, grafted chitosan natural polymer with carbon nanotubes has been incorporated to increase the mechanical strength of these composites. Chitosan composites are thus emerging as potential materials for artificial bone and bone regeneration in tissue engineering. Herein, the preparation, mechanical properties, chemical interactions and in vitro activity of chitosan composites for bone tissue engineering will be discussed. PMID:20948907

Venkatesan, Jayachandran; Kim, Se-Kwon

2010-01-01

171

Comparison of thermal and chemical treatments of ultrathin chitosan films  

NASA Astrophysics Data System (ADS)

Chitosan is a biodegradable polysaccharide derived from seashell waste products. The high water absorbency and biocompatibility of chitosan have enabled its use as a hydrogel in specialty biomedical applications. Chitosan can be dissolved in weakly acidic solutions enabling its use in applications such as films and gels, which can be converted into chitin by a chemical process known as acetylation. We present the results of several experiments in which changes in the thickness, index of refraction and molecular environment in response to changes in relative humidity for ultrathin films of chitosan are examined as a function of exposure to temperatures above 150 degrees Celsius. Measurements made by ellipsometry and FTIR spectroscopy indicate that changes in the thickness and index of refraction of the films are accompanied by a change in the infrared absorption spectra similar to that associated with acetylation, which is typically accomplished by exposure of chitosan to acetic anhydride. We believe that these changes are responsible for reduced equilibrium water content in the films at all relative humidity values studied, and may offer a simple method for converting chitosan into a chitin-like material.

Murray, Chris; Dutcher, John

2006-03-01

172

Antibacterial Activity of Gamma-irradiated Chitosan Against Denitrifying Bacteria  

NASA Astrophysics Data System (ADS)

In order to find an environmentally benign substitute to hazardous inhibitory agents, the inhibitory effect of ?-irradiated chitosans against a mixed culture of denitrifying bacteria was experimentally evaluated. Unlike other studies using pure aerobic cultures, the observed effect was not a complete inhibition but a transient inhibition reflected by prolonged lag phases and reduced growth rates. Raw chitosan under acid conditions (pH 6.3) exerted the strongest inhibition followed by the 100 kGy and 500 kGy irradiated chitosans respectively. Therefore because the molecular weight of chitosan decreases with the degree of ?-irradiation, the inhibitory properties of chitosan due to its high molecular weight were more relevant than the inhibitory properties gained due to the modification of the surface charge and/or chemical structure by ?-irradiation. High dosage of ?-irradiated appeared to increase the growth of mixed denitrifying bacteria in acid pH media. However, in neutral pH media, high dosage of ?-irradiation appeared to enhance the inhibitory effect of chitosan.

Vilcáez, Javier; Watanabe, Tomohide

2010-11-01

173

Physicochemical and functional characteristics of radiation-processed shrimp chitosan  

NASA Astrophysics Data System (ADS)

The effects of gamma irradiation on chitosan samples were determined in terms of physicochemical and functional properties. Shrimp chitosan was extracted from shell using a chemical process involving demineralization, deproteinization, decolorization and deacetylation. Commercial snow chitosan was also used. Samples (in a solid state) were given irradiation dose of 25 kGy at a dose rate of 1.1013 kGy/h in air and 0 kGy samples were used as controls. Results showed that moisture contents were between 8.690% and 13.645%. There were no significant differences ( P>0.05) in the degree of deacetylation of the chitosan samples. Significant differences ( P<0.05) were observed in the viscosity and viscosity-average molecular weight of the chistosan samples. Viscosity and molecular weight decreased when the samples were given the irradiation dose of 25 kGy. Chitosan samples had low antioxidant activity compared with BHT. Water binding capacity ranged from 582.40% to 656.75% and fat binding capacity was between 431.00% and 560.55%. Irradiation had a major effect on the viscosity and the viscosity-average molecular weight of the chitosan samples.

Ocloo, F. C. K.; Quayson, E. T.; Adu-Gyamfi, A.; Quarcoo, E. A.; Asare, D.; Serfor-Armah, Y.; Woode, B. K.

2011-07-01

174

THE USE OF CHITOSAN TO DAMAGE CRYPTOCOCCUS NEOFORMANS BIOFILMS  

PubMed Central

The use of indwelling medical devices (e.g. pacemakers, prosthetic joints, catheters, etc) continues to increase, yet these devices are all too often complicated by infections with biofilm-forming microbes with increased resistance to antimicrobial agents and host defense mechanisms. We investigated the ability of chitosan, a polymer isolated from crustacean exoskeletons, to damage biofilms formed by the pathogenic fungus Cryptococcus neoformans. Using 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium-hydroxide (XTT) reduction assay and CFU determinations, we showed that chitosan significantly reduced both the metabolic activity of the biofilms and cell viability, respectively. We further demonstrated that chitosan penetrated biofilms and damaged fungal cells using confocal and scanning electron microscopy. Notably, melanization, an important virulence determinant of C. neoformans, did not protect cryptococcal biofilms against chitosan. The chitosan concentrations used in this study to evaluate fungal biofilm susceptibility were not toxic to human endothelial cells. Our results indicate that cryptococcal biofilms are susceptible to treatment with chitosan, suggesting an option for the prevention or treatment of fungal biofilms on indwelling medical devices. PMID:19819009

Martinez, Luis R.; Mihu, Mircea Radu; Han, George; Frases, Susana; Cordero, Radames J. B.; Casadevall, Arturo; Friedman, Adam J.; Friedman, Joel M.; Nosanchuk, Joshua D.

2009-01-01

175

Immobilization of naringin onto chitosan substrates by using ozone activation.  

PubMed

Ozone oxidation can easily produce peroxides containing active free radicals that can be used for the surface modification of biomaterials. This process is highly efficient and nontoxic. In this research, naringin, an HMG-CoA reductase inhibitor that can promote bone formation, was immobilized onto a chitosan film using ozone activation. First, a chitosan film was treated by ozone to produce peroxides; these peroxides were then quantified and their amount was optimized by an iodide assay. For the in vitro delivery of naringin, a chitosan-naringin substrate was immersed in phosphate-buffered saline to quantify the released amount of naringin. It was found that the immobilized naringin was slowly released over the course of two weeks, where its concentration in the medium was controlled by this delivery process. The results of cell culture showed that cell viability and early osteogenic differentiation, as measured by alkaline phosphatase expression, were promoted with the immobilized naringin on chitosan substrates. The expression of osteogenic proteins, including type-I collagen, bone siloprotein, and osteocalcin, were also enhanced. According to the results of Smad1 and Smad6 phosphorylation, immobilized naringin on ozonated chitosan substrates would be able to initiate bone morphogenetic protein-Smad signaling by activating receptor Smad and by suppressing inhibitory Smad. The results in this research demonstrated that the naringin-chitosan substrate produced by biocompatible ozone activation was highly osteoconductive without cytotoxicity. PMID:24317428

Li, Chung Hsing; Wang, Jing Wei; Ho, Ming Hua; Shih, Jia Lin; Hsiao, Sheng Wen; Thien, Doan Van Hong

2014-03-01

176

Useful Extend-release Chitosan Tablets with High Antioxidant Activity  

PubMed Central

The antioxidant properties of different low molecular weight (LMW) chitosans (CS1; 22 kDa, CS2; 38 kDa, CS3; 52 kDa, CS4; 81 kDa) were examined for possible use in extended-release tablets. The criteria used were the ability of the chitosans to reduce Cu2+, and hydroxyl and superoxide radicals and N-centered radicals derived from 1,1'-diphenyl-2-picrylhydrazyl, via the use of ESR spectrometry. CS2 showed the highest scavenging activity. CS1 and CS3, however, were much less effective and CS4 was not a viable antioxidant. The results suggest that CS2 could be useful in combating the development of oxidative stress. A series of chitosan tablets were prepared using a spray drying method and evaluated as an extended-release matrix tablet using theophylline (TPH) as a model drug. The release of TPH from the different MW chitosan tablets increased with increasing MW of the chitosan used. CS2, CS3 and CS4 showed a reasonable release activity, but CS1 showed the shortest release activity. Moreover, the CS2-TPH tablet showed the highest scavenging activity of the three chitosan tablets (CS2-CS4) using 2,2’-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) radicals. These results suggest that a CS2-TPH tablet could be potentially useful in an extended-release matrix tablet with a high antioxidant activity.

Yasufuku, Taira; Anraku, Makoto; Kondo, Yuko; Hata, Toshiyuki; Hirose, Junzo; Kobayashi, Nobuyuki; Tomida, Hisao

2010-01-01

177

Chitosan-Based Vector\\/DNA Complexes for Gene Delivery: Biophysical Characteristics and Transfection Ability  

Microsoft Academic Search

Purpose. Chitosan, a natural cationic polysaccharide, is a candidate non-viral vector for gene delivery. With the aim of developing this system, various biophysical characteristics of chitosan-condensed DNA complexes were measured, and transfections were performed.

Patrick Erbacher; Shaomin Zou; Thierry Bettinger; Anne-Marie Steffan; Jean-Serge Remy

1998-01-01

178

RESEARCH PAPER Chitosan Film Containing Poly(D,L-Lactic-Co-Glycolic  

E-print Network

RESEARCH PAPER Chitosan Film Containing Poly(D,L-Lactic-Co-Glycolic Acid) Nanoparticles: A Platform through chitosan films (1­4). Poly(D,L-lactic-co-glycolic acid) (PLGA) is another biodegradable polymer

Sridhar, Srinivas

179

Preparation and characterization of micelles of oligomeric chitosan linked to all-trans retinoic acid  

Microsoft Academic Search

New amphiphilic chitosan derivatives of all trans retinoic acid–chitosan (RA–chitosan) with different molar feeding ratios of all trans retinoic acid (ATRA) were synthesized. The degree of ATRA substitution ranged from 8.72% to 18.78%. The RA–chitosan formed micelles with an average size of 142.14–208.4nm, and zeta potential of +27.25 to 34.48mV. The critical association concentration (CAC) was found to range from

Ali Fattahi; Mohammad-Ali Golozar; Jaleh Varshosaz; Hamid Mirmohammad Sadeghi; Mohammadhossein Fathi

180

Electrochemical preparation of chitosan/hydroxyapatite composite coatings on titanium substrates.  

PubMed

Composite coatings containing brushite (CaHPO(4). 2H(2)O) and chitosan were prepared by electrochemical deposition. The brushite/chitosan composites were converted to hydroxyapatite/chitosan composites in aqueous solutions of sodium hydroxide. The coatings ranged from approximately 1 to 15% chitosan by weight. Qualitative assessment of the coatings showed adhesion significantly improved over that observed for electrodeposited coatings of pure HA. PMID:12889012

Redepenning, Jody; Venkataraman, Guhanand; Chen, Jun; Stafford, Nathan

2003-08-01

181

Dispersion of chitosan on perlite for enhancement of copper(II) adsorption capacity  

Microsoft Academic Search

Chitosan coated perlite beads were prepared by drop-wise addition of slurry, made of chitosan dissolved in oxalic acid and perlite, to an alkaline bath (0.7M NaOH). The beads that contained 32% chitosan enhanced the accessibility of OH and amine groups present in chitosan for adsorption of copper ions. The experiments using Cu(II) ions were carried out in the concentration range

Shameem Hasan; Tushar K. Ghosh; Dabir S. Viswanath; Veera M. Boddu

2008-01-01

182

Chitosan–EDTA New Combination is a Promising Candidate for Treatment of Bacterial and Fungal Infections  

Microsoft Academic Search

Chitosan is an attractive preparation widely used as a pharmaceutical excipient. This study aimed to evaluate the antimicrobial\\u000a activities of chitosan derivatives, EDTA, and the newly developed chitosan–EDTA combination against Gram-negative and Gram-positive\\u000a bacteria as well as Candida albicans. Antimicrobial activity was studied. Both minimal Inhibitory Concentrations (MIC) and minimal biocidal concentrations (MBC)\\u000a were determined. Chitosan acetic acid recorded lower

Amany A. El-SharifMohamed; Mohamed H. M. Hussain

2011-01-01

183

Chitosan-DNA nanoparticles as gene carriers: synthesis, characterization and transfection efficiency  

Microsoft Academic Search

Chitosan-DNA nanoparticles were prepared using a complex coacervation process. The important parameters for the nanoparticle synthesis were investigated, including the concentrations of DNA, chitosan and sodium sulfate, temperature of the solutions, pH of the buffer, and molecular weights of chitosan and DNA. At an amino group to phosphate group ratio (N\\/P ratio) between 3 and 8 and a chitosan concentration

Hai-Quan Mao; Krishnendu Roy; Vu L. Troung-Le; Kevin A. Janes; Kevin Y. Lin; Yan Wang; J. Thomas August; Kam W. Leong

2001-01-01

184

SOLVENT PURIFICATION AND FLUOR SELECTION FOR GADOLINIUM-LOADED LIQUID SCINTILLATORS  

SciTech Connect

The last decade has seen huge progress in the study of neutrinos, elementary sub-atomic particles. Continued growth in the fi eld of neutrino research depends strongly on the calculation of the neutrino mixing angle ?13, a fundamental neutrino parameter that is needed as an indicative guideline for proposed next-generation neutrino experiments. Experiments involving reactor antineutrinos are favored for the calculation of ?13 because their derivation equation for ?13 is relatively simple and unambiguous. A Gd-loaded liquid scintillator (Gd-LS) is the centerpiece of the detector and it consists of ~99% aromatic solvent, ~0.1% Gd, and < 1% fl uors. Key required characteristics of the Gd-LS are long-term chemical stability, high optical transparency, and high photon production by the scintillator. This summer’s research focused on two important aspects of the detector: (1) purifi cation of two selected scintillation solvents, 1, 2, 4-trimethylbenzene (PC) and linear alkyl benzene (LAB), to improve the optical transparency and long-term chemical stability of the Gd-LS, and (2) investigation of the added fl uors to optimize the photon production. Vacuum distillation and column separation were used to purify PC and LAB, respectively. Purifi cation was monitored using UV-visible absorption spectra and verifi ed in terms of decreased solvent absorption at 430nm. Absorption in PC at 430nm decreased by a factor slightly >10 while the absorption in LAB was lowered by a factor of ~5. Photon production for every possible combination of two solvents, four primary shifters, and two secondary shifters was determined by measuring the Compton-Scattering excitation induced by an external Cs-137 gamma source (E? ~ 662-keV). The ideal shifter concentration was identifi ed by measuring the photon production as a function of shifter quantity in a series of samples. Results indicate that 6g/L p-terphenyl with 150mg/L 1,4-Bis(2-methylstyryl)-benzene (bis-MSB) produces the maximum light yield for PC and 6g/L 2-(4-biphenylyl)-5-(4-tert-butyl-phenyl)-1,3,4-oxadiazole with 50mg/L bis-MSB optimizes the light yield for LAB. Future work should focus on obtaining the fl uorescence spectra for each of the shifters and studying the optical transparency of the LS as a function of shifter quantity.

Kesete, T.; Storm, A.; Hahn, R. L.; Yeh, M.; Seleem, S.

2007-01-01

185

Synthesis and Investigation of Chitosan Derivatives Formed by Reaction with Acyl Chlorides  

Microsoft Academic Search

Chitosan is a linear polysaccharide obtained from chitin deacetylation. Several applications of chitosan have been proposed in specialized literature: water treatment, cosmetic, food additives, development of biomaterials, and mainly drug delivery. In the present paper chitosan was hydrophobized by esterification reaction with acyl chlorides; its derivatives were swelling in water and characterized by C? and H?NMR and infrared spectroscopy. The

Máira R. Rodrigues

2005-01-01

186

Adsorption of Hexavalent Chromium on Chitosan Beads: Sorption Isotherms and Kinetics  

Microsoft Academic Search

Chitosan is a biopolymer that is usually obtained in a flaked form, nonporous and partially soluble in acidic media. The low porosity of the polymer introduces diffusion constraints which are rate limiting. Modifying the structure of the chitosan is a way to improve the accessibility of the adsorption sites. In this study, the modifications were carried out by dissolving chitosan

SANDRINE BOSINCO; ERIC GUIBAL; JEAN ROUSSY; PIERRE LECLOIREC

1998-01-01

187

Removal of Copper and Nickel from Aqueous Solutions Using Chitosan Coated on Perlite as Biosorbent  

Microsoft Academic Search

Chitosan has been increasingly studied as an adsorbent for removing heavy metal ions from aqueous solutions through adsorption due to the presence of free amino and hydroxyl groups. For most of the studies chitosan has been used in the form of flakes, powder, or hydrogel beads. Chitosan in its natural form has a tendency to agglomerate or to form gel

S. Kalyani; J. Ajitha Priya; P. Srinivasa Rao; A. Krishnaiah

2005-01-01

188

Effect of ion size of various salts of Chitosan on the electrical properties  

NASA Astrophysics Data System (ADS)

The present investigation reports, the influence of ion sizes of various salts of Chitosan on the electrical properties, by dissolving Chitosan in various acids like acetic, adipic, formic and succinic acids and for various concentration. An unusual behavior of ac impedance has been observed which may be due to the increase in amorphousity when the size of the salts of Chitosan ion increases.

Mohan, C. Raja; Murugan, S.; Nithiananthi, P.; Jayakumar, K.

2013-06-01

189

Cell Wall Chitosan Is Necessary for Virulence in the Opportunistic Pathogen Cryptococcus neoformans ?  

PubMed Central

Cryptococcus neoformans is an opportunistic fungal pathogen that causes meningoencephalitis. Its cell wall is composed of glucans, proteins, chitin, and chitosan. Multiple genetic approaches have defined a chitosan-deficient syndrome that includes slow growth and decreased cell integrity. Here we demonstrate chitosan is necessary for virulence and persistence in the mammalian host. PMID:21784998

Baker, Lorina G.; Specht, Charles A.; Lodge, Jennifer K.

2011-01-01

190

CHITOSAN AS A MEMBRANE MATERIAL FOR PERVAPORATION SEPARATION OF ISOPROPANOL-WATER MIXTURES  

Microsoft Academic Search

Chitosan based pervaporation membranes were prepared from locally available shrimp shells using various chemical treatments. The dried shrimp shells were first grinded and treated with sodium hydroxide aqueous solution and then followed by treating with hydrochloric acid solution to remove the calcium content before chitin is produced. The chitosan membranes were prepared by dissolving a pre-weighed quantity of chitosan into

HASHIM HASSAN; MOHD GHAZALI MOHD NAWAWI

191

Flocculation of Organic Matter and Aluminum in Water Using Chitosan-Inorganic Coagulant  

Microsoft Academic Search

Chitosan can be a potential substitute for aluminum salts and synthetic polyelectrolytes in water treatment because it can: (1) avoid the health effects from residual aluminum (III) and synthetic polymers; (2) produce biodegradable sludge; and (3) reuse the crab shell. In this study, the chitosan flocculation characteristics in water were studied firstly, and then the combined flocculation of chitosan and

Ming Jiang; Xuefei Zhou; Yalei Zhang; Jinsheng Lou

2009-01-01

192

Dyeing and antimicrobial characteristics of chitosan treated wool fabrics with henna dye  

Microsoft Academic Search

Chitosan, a naturally available biopolymer which is now increasingly being used as a functional finish on textile substrates to impart antimicrobial characteristics and increase dye uptake of fabrics was applied on wool fabrics. Henna a natural dye with proven bactericidal properties was applied on wool fabrics along with chitosan to impart antimicrobial characteristics. The effect of chitosan application on the

V. R. Giri Dev; J. Venugopal; S. Sudha; G. Deepika; S. Ramakrishna

2009-01-01

193

Enzymatic Grafting of Peptides from Casein Hydrolysate to Chitosan. Potential for Value-Added Byproducts from  

E-print Network

formed from reactions with glucosamine (the monomeric unit of chitosan) and the model dipeptide Tyr by reacting chitosan (0.32 w/v%) with acid-hydrolyzed casein (0.5 w/v %) using tyrosinase. After reaction). The characteristic of chitosan that is most important for our study is that this polymer has nucleophilic primary

Raghavan, Srinivasa

194

Emerging Biomedical Applications of Nano-Chitins and Nano-Chitosans Obtained via Advanced Eco-Friendly Technologies from Marine Resources  

PubMed Central

The present review article is intended to direct attention to the technological advances made in the 2010–2014 quinquennium for the isolation and manufacture of nanofibrillar chitin and chitosan. Otherwise called nanocrystals or whiskers, n-chitin and n-chitosan are obtained either by mechanical chitin disassembly and fibrillation optionally assisted by sonication, or by e-spinning of solutions of polysaccharides often accompanied by poly(ethylene oxide) or poly(caprolactone). The biomedical areas where n-chitin may find applications include hemostasis and wound healing, regeneration of tissues such as joints and bones, cell culture, antimicrobial agents, and dermal protection. The biomedical applications of n-chitosan include epithelial tissue regeneration, bone and dental tissue regeneration, as well as protection against bacteria, fungi and viruses. It has been found that the nano size enhances the performances of chitins and chitosans in all cases considered, with no exceptions. Biotechnological approaches will boost the applications of the said safe, eco-friendly and benign nanomaterials not only in these fields, but also for biosensors and in targeted drug delivery areas. PMID:25415349

Muzzarelli, Riccardo A. A.; El Mehtedi, Mohamad; Mattioli-Belmonte, Monica

2014-01-01

195

Therapeutic efficiency of folated poly(ethylene glycol)-chitosan-graft-polyethylenimine-Pdcd4 complexes in H-ras12V mice with liver cancer  

PubMed Central

Background Chitosan and chitosan derivatives have been proposed as alternative and biocompatible cationic polymers for nonviral gene delivery. However, the low transfection efficiency and low specificity of chitosan is an aspect of this approach that must be addressed prior to any clinical application. In the present study, folated poly(ethylene glycol)-chitosan-graft-polyethylenimine (FPCP) was investigated as a potential folate receptor-overexpressed cancer cell targeting gene carrier. Methods The FPCP copolymer was synthesized in two steps. In the first step, folate-PEG was synthesized by an amide formation reaction between the activated carboxyl groups of folic acid and the amine groups of bifunctional poly(ethylene glycol) (PEG). In the second step, FPCP was synthesized by an amide formation reaction between the activated carboxyl groups of folate-PEG and amine groups of CHI-g-polyethyleneimine (PEI). The composition of FPCP was characterized by 1H nuclear magnetic resonance. Results: FPCP showed low cytotoxicity in various cell lines, and FPCP-DNA complexes showed good cancer cell specificity as well as good transfection efficiency in the presence of serum. Further, FPCP-Pdcd4 complexes reduced tumor numbers and progression more effectively than PEI 25 kDa in H-ras12V liver cancer mice after intravenous administration. Conclusion Our data suggest that FPCP, which has improved transfection efficiency and cancer cell specificity, may be useful in gene therapy for liver cancer. PMID:23620665

Kim, You-Kyoung; Minai-Tehrani, Arash; Lee, Jae-Ho; Cho, Chong-Su; Cho, Myung-Haing; Jiang, Hu-Lin

2013-01-01

196

[The use of shells made of poly(ethylene glycol) and chitosan to ensure the biocompatibility of nanoparticles in biomedical applications].  

PubMed

Biomedical applications of nanoparticles require that these structures are characterized by broadly defined biocompatibility. The best way to achieve this goal is to use an appropriate polymer coating, which can modify the surface properties of the nanoparticles core. The shells are formed from biodegradable material, so that the products of their decomposition can be easily eliminated from the body. Coating of nanoparticles allows to increase their stability (both in aqueous solutions and in the bloodstream), prevents agglomeration, provides the hydrophilicity of the surface and allows to attach various molecules such as drugs and tumor targeting ligands in cancer therapy. The polymer coating significantly affects the reduction of toxicity of nanoparticles and their interactions with different cell types. Chitosan and poly(ethylene glycol) (PEG) are frequently used for coating of nanostructures due to the availability and favourable properties. A major advantage of PEG is its ability to prolong the circulation time of nanoparticles injected into the bloodstream by preventing their opsonization and reducing the uptake by macrophages. Chitosan, because of its positive charge, strongly interacts with cell membranes and mucosal surfaces, which can be useful in drug delivery systems. However, it should be remembered that the molar mass and the degree of deacetylation of the used chitosan significantly affect its characteristics. The use of combined shells made of poly(ethylene glycol) and chitosan or coatings formed from new PEG based copolymers aims at further optimization of the properties of nanoparticle carriers to increase their safety and reliability in biomedical applications. PMID:24967783

Kubiak, Tomasz

2014-01-01

197

Poly(vinyl alcohol)-coated chitosan microparticles act as an effective oral vaccine delivery system for hepatitis B vaccine in rat model.  

PubMed

The present study focused on the development of an effective oral vaccine delivery system of poly(vinyl alcohol)-coated chitosan microparticles-based recombinant hepatitis B vaccine. Chitosan microparticles were prepared by ionotropic gelation technique; they were loaded with recombinant hepatitis B vaccine and coated with poly(vinyl alcohol). The average sizes of the microparticles were measured in the range of 100-410 nm. The optimal loading capacity and loading efficiency were recorded around 3.4 and 74%, respectively. In vitro release study shows that the prepared microparticles release the antigen in a sustained manner. Moreover, the microparticles were resistant to simulated gastric environment and release the antigen in the targeted intestinal milieu. Furthermore, oral immunisation of rats with poly(vinyl alcohol)-coated chitosan hepatitis-B microparticles vaccine shows comparable seroprotective immune response to presently practiced intramuscular vaccination. The results demonstrated that poly(vinyl alcohol)-coated chitosan microparticles have the potential for being used as an oral vaccine delivery system for hepatitis B vaccine and may be a suitable alternative for needle-based vaccination. PMID:25429498

Shrestha, Bijaya; Rath, Jyoti Prakash

2014-12-01

198

Surface grafted chitosan gels. Part II. Gel formation and characterization.  

PubMed

Responsive biomaterial hydrogels attract significant attention due to their biocompatibility and degradability. In order to make chitosan based gels, we first graft one layer of chitosan to silica, and then build a chitosan/poly(acrylic acid) multilayer using the layer-by-layer approach. After cross-linking the chitosan present in the polyelectrolyte multilayer, poly(acrylic acid) is partly removed by exposing the multilayer structure to a concentrated carbonate buffer solution at a high pH, leaving a surface-grafted cross-linked gel. Chemical cross-linking enhances the gel stability against detachment and decomposition. The chemical reaction between gluteraldehyde, the cross-linking agent, and chitosan was followed in situ using total internal reflection Raman (TIRR) spectroscopy, which provided a molecular insight into the complex reaction mechanism, as well as the means to quantify the cross-linking density. The amount of poly(acrylic acid) trapped inside the surface grafted films was found to decrease with decreasing cross-linking density, as confirmed in situ using TIRR, and ex situ by Fourier transform infrared (FTIR) measurements on dried films. The responsiveness of the chitosan-based gels with respect to pH changes was probed by quartz crystal microbalance with dissipation (QCM-D) and TIRR. Highly cross-linked gels show a small and fully reversible behavior when the solution pH is switched between pH 2.7 and 5.7. In contrast, low cross-linked gels are more responsive to pH changes, but the response is fully reversible only after the first exposure to the acidic solution, once an internal restructuring of the gel has taken place. Two distinct pKa's for both chitosan and poly(acrylic acid), were determined for the cross-linked structure using TIRR. They are associated with populations of chargeable groups displaying either a bulk like dissociation behavior or forming ionic complexes inside the hydrogel film. PMID:25006685

Liu, Chao; Thormann, Esben; Claesson, Per M; Tyrode, Eric

2014-07-29

199

Chitosan for gene delivery and orthopedic tissue engineering applications.  

PubMed

Gene therapy involves the introduction of foreign genetic material into cells in order exert a therapeutic effect. The application of gene therapy to the field of orthopaedic tissue engineering is extremely promising as the controlled release of therapeutic proteins such as bone morphogenetic proteins have been shown to stimulate bone repair. However, there are a number of drawbacks associated with viral and synthetic non-viral gene delivery approaches. One natural polymer which has generated interest as a gene delivery vector is chitosan. Chitosan is biodegradable, biocompatible and non-toxic. Much of the appeal of chitosan is due to the presence of primary amine groups in its repeating units which become protonated in acidic conditions. This property makes it a promising candidate for non-viral gene delivery. Chitosan-based vectors have been shown to transfect a number of cell types including human embryonic kidney cells (HEK293) and human cervical cancer cells (HeLa). Aside from its use in gene delivery, chitosan possesses a range of properties that show promise in tissue engineering applications; it is biodegradable, biocompatible, has anti-bacterial activity, and, its cationic nature allows for electrostatic interaction with glycosaminoglycans and other proteoglycans. It can be used to make nano- and microparticles, sponges, gels, membranes and porous scaffolds. Chitosan has also been shown to enhance mineral deposition during osteogenic differentiation of MSCs in vitro. The purpose of this review is to critically discuss the use of chitosan as a gene delivery vector with emphasis on its application in orthopedic tissue engineering. PMID:23676471

Raftery, Rosanne; O'Brien, Fergal J; Cryan, Sally-Ann

2013-01-01

200

Understanding the adsorption mechanism of chitosan onto poly(lactide-co-glycolide) particles  

PubMed Central

Polyelectrolyte-coated nanoparticles or microparticles interact with bioactive molecules (peptides, proteins or nucleic acids) and have been proposed as delivery systems for these molecules. However, the mechanism of adsorption of polyelectrolyte onto particles remains unsolved. In this study, cationic poly(lactide-co-glycolide) (PLGA) nanoparticles were fabricated by adsorption of various concentrations of a biodegradable polysaccharide, chitosan (0–2.4 g/L), using oil-in-water emulsion and solvent evaporation techniques. The particle diameter, zeta-potential, and chitosan adsorption of chitosan coated PLGA nanoparticles confirmed the increase of polyelectrolyte adsorption. Five adsorption isotherm models (Langmuir, Freundlich, Halsey, Henderson and Smith) were applied to the experimental data in order to better understand the mechanism of adsorption. Both particle diameter and chitosan adsorption increased with chitosan concentration during adsorption. A good correlation was obtained between PLGA-chitosan nanoparticle size and adsorbed chitosan on the surface, suggesting the increased particle size was primarily due to the increased chitosan adsorption. The zeta-potential of chitosan-coated PLGA nanoparticles was positive and increased with chitosan adsorbed until a maximum value (+55 mV) was reached at approximately 0.4–0.6 g/L; PLGA nanoparticles had a negative zeta-potential (?20 mV) prior to chitosan adsorption. Chitosan adsorption on PLGA nanoparticles followed a multilayer adsorption behavior, although the Langmuir monolayer equation held at low concentrations of chitosan. The underlying reasons for adsorption of chitosan on PLGA nanoparticles were thought to be the cationic nature of chitosan, high surface energy and microporous non-uniform surface of PLGA nanoparticles. PMID:18602994

Guo, Chunqiang; Gemeinhart, Richard A.

2008-01-01

201

Zwitterionic Chitosan-Polyamidoamine Dendrimer Complex Nanoparticles as a pH-Sensitive Drug Carrier  

PubMed Central

Polyamidoamine (PAMAM) dendrimers have been widely explored as carriers of therapeutics and imaging agents. However, amine-terminated PAMAM dendrimers is rarely utilized in systemic applications due to its cytotoxicity and risk of opsonization, caused by its cationic charges. Such undesirable effects may be mitigated by shielding the PAMAM dendrimer surface with polymers that reduce the charges. However, this shielding may also interfere with PAMAM dendrimers’ ability to interact with target cells, thus reducing cellular uptake and overall efficacy of the delivery system. Therefore, we propose to use zwitterionic chitosan (ZWC), a new chitosan derivative, which has a unique pH-sensitive charge profile, as an alternative biomaterial to modify the cationic surface of PAMAM dendrimers. Stable electrostatic complex of ZWC and PAMAM dendrimers was formed at pH 7.4, where the PAMAM dendrimer surface was covered with ZWC, as demonstrated by fluorescence spectroscopy and transmission electron microscopy. The presence of ZWC coating protected red blood cells and fibroblast cells from hemolytic and cytotoxic activities of PAMAM dendrimers, respectively. Confocal microscopy showed that the protective effect of ZWC disappeared at low pH as the complex dissociated due to the charge conversion of ZWC, allowing PAMAM dendrimers to enter cells. These results demonstrate that ZWC is able to provide a surface coverage of PAMAM dendrimers in a pH-dependent manner and, thus, enhance the utility of PAMAM dendrimers as a drug carrier to solid tumors with acidifying microenvironment. PMID:23510114

Liu, Karen C.; Yeo, Yoon

2013-01-01

202

MASKER MASKER TARGET TARGET TARGET  

E-print Network

from a large speech database (Ives et al,2005). The original speech is from one speaker Probabilitycorrect -6 dB 0 dB Listeners were presented with two phrases of concurrent speech syllables. The masker syllables coincided with the second and third target syllables. The speech syllables were taken

Ives, D. Timothy

203

Chitosan-based controlled porosity osmotic pump for colon-specific delivery system: Screening of formulation variables and in vitro investigation  

Microsoft Academic Search

A microbially triggered colon-targeted osmotic pump (MTCT-OP) has been studied. The gelable property at acid condition and colon-specific biodegradation of chitosan were used to: (1) produce the osmotic pressure, (2) form the drug suspension and (3) form the in situ delivery pores for colon-specific drug release, respectively. The scanning electron microscopy (SEM) study and the calculation of membrane permeability were

Hui Liu; Xing-Gang Yang; Shu-Fang Nie; Lan-Lan Wei; Li-Li Zhou; Hong Liu; Ren Tang; Wei-San Pan

2007-01-01

204

Synthesis and antimicrobial activity of a water-soluble chitosan derivative with a fiber-reactive group  

Microsoft Academic Search

A novel fiber-reactive chitosan derivative was synthesized in two steps from a chitosan of low molecular weight and low degree of acetylation. First, a water-soluble chitosan derivative, N-[(2-hydroxy-3-trimethylammonium)propyl]chitosan chloride (HTCC), was prepared by introducing quaternary ammonium salt groups on the amino groups of chitosan. This derivative was further modified by introducing functional (acrylamidomethyl) groups, which can form covalent bonds with

Sang-Hoon Lim; Samuel M. Hudson

2004-01-01

205

Preparation, structure and crystallinity of chitosan nano-fibers by a solid–liquid phase separation technique  

Microsoft Academic Search

Chitosan acetate nano-fibers were fabricated via a solid–liquid phase separation technique. The chitosan acetate structure was influenced by phase separation temperature, chitosan concentration and acetic acid concentration. Uniform nano-fibrous chitosan acetate of 50–500nm in diameter was engineered at 0.05% (w\\/v) chitosan and 0.025% (v\\/v) acetic acid in liquid nitrogen, as opposed to film-shape and micro-fibrous structure at ?18°C and ?80°C

Jianhao Zhao; Wanqing Han; Haodong Chen; Mei Tu; Rong Zeng; Yunfeng Shi; Zhengang Cha; Changren Zhou

2011-01-01

206

Detection of chlorine-labelled chitosan in Scots pine by energy-dispersive X-ray spectroscopy  

Microsoft Academic Search

The aim of this study was to use energy-dispersive X-ray spectroscopy (EDX) to localize chitosan in the cell wall of chitosan-impregnated\\u000a Scots pine. It was of interest to investigate the concentration of chitosan in wood to gain further knowledge and understanding\\u000a of the distribution of chitosan in the wooden matrix. After deacetylation, chitosan was re-acetylated with chloroacetic anhydride\\u000a to achieve

Erik Larnøy; Morten Eikenes; Holger Militz

2011-01-01

207

Biological effect of irradiated chitosan on plants in vitro.  

PubMed

For degradation of chitosan, chitosan with an 80% degree of deacetylation and a weight-average molecular mass (Mw) of approx. 48 kDa was irradiated with gamma-rays at doses up to 200 kGy in a 10% (w/v) solution. The Mw of chitosan was reduced from 48 to 9.1 kDa by irradiation. The characteristics of irradiated chitosan were analysed by using Fourier-transform IR spectroscopy and an elemental analyser. The amino group was found to be stable, whereas the C-O-C group decreased with increase in the dose. The product of chitosan irradiated at 100 kGy with an Mw of approx. 16 kDa showed the strongest growth promotion effect on plants in vitro. For shoot culture, supplementation with irradiated chitosan increased the fresh biomass of shoot clusters (7.2-17.0%) as well as the shoot multiplication rate (17.9-69.0%) for Chrysanthemum morifolium (florist's chrysanthemum), Limonium latifolium (limonium or sea-lavender), Eustoma grandiflorum (lisianthus, tulip gentian or Texas bluebell) and Fragaria ananassa (modern garden strawberry). The optimum concentrations of irradiated chitosan were found to be approx. 70-100 mg/l for chrysanthemum, 50-100 mg/l for lisianthus and 30-100 mg/l for limonium. For the plantlet culture, the optimum concentrations were found to be approx. 100 mg/l for chrysanthemum, 30 mg/l for lisianthus, 40 mg/l for limonium and 50 mg/l for strawberry. Supplementation with optimum concentrations of irradiated chitosan resulted in a significant increase in the fresh biomass (68.1% for chrysanthemum, 48.5% for lisianthus, 53.6% for limonium and 26.4% for strawberry), shoot height (19.4% for chrysanthemum, 16.5% for lisianthus, 33.9% for limonium and 25.9% for strawberry) and root length (40.6% for chrysanthemum, 66.9% for lisianthus, 23.4% for limonium and 22.6% for strawberry). In addition, treatment with irradiated chitosan enhanced the activity of chitosanase in treated plants and also improved the survival ratio and growth of the transferred plantlets acclimatized for 10-30 days under greenhouse conditions. PMID:15104541

Luan, Le Q; Ha, Vo T T; Nagasawa, Naotsugu; Kume, Tamikazu; Yoshii, Fumio; Nakanishi, Tomoko M

2005-02-01

208

Antimicrobial finish of textiles by chitosan UV-curing.  

PubMed

The purpose of this research work was to develop a textile finish based on the radical UV-curing of chitosan on textiles to confer antimicrobial properties. Chitosan is a biopolymer with unique properties such as biodegradability, non-toxicity, antimicrobial activity. In this work cotton or silk fabrics and synthetic filter fabrics were impregnated with an acid solution of chitosan added of the photoinitiator in the proper amount and cured at room temperature by exposure to UV lamp. Process conditions such as percentage add-on, dilution, chitosan-fabric contact time, irradiation time and power, were optimized. The antimicrobial activity of finished fabrics was tested according to ASTM E 2149-01 standard test performed with Escherichia Coli ATCC 8739. Moreover dyeing test with Turquoise Telon dye were carried out to evaluate the treatment homogeneity while the amino group content was determined by ninhydrin assay. Moreover on cotton and silk fabrics the treatment fastness to domestic laundering was tested, according to UNI EN ISO105-C01. Obtained results showed a strong antimicrobial activity conferred by the treatment, homogeneous on fabric surface. It is evident already at low add-on, without affecting the hand properties of natural fabrics and the filtration characteristics of the synthetic filter fabrics. Finally, washing fastness was better for samples prepared with a better penetration of chitosan inside the fibers. PMID:22905533

Ferrero, Franco; Periolatto, Monica

2012-06-01

209

Chitosan-hydroxycinnamic acid conjugates: preparation, antioxidant and antimicrobial activity.  

PubMed

In this study, the antioxidant and antimicrobial activities of chitosan-caffeic acid, chitosan-ferulic acid, and chitosan-sinapic acid conjugates with different grafting ratios were investigated. The synthesized chitosan-hydroxycinnamic acid conjugates were verified by performing (1)H NMR and differential scanning calorimetry analysis. The antioxidant activities of the conjugates were increased compared to the unmodified chitosan, by 1.79-fold to 5.05-fold (2,2-diphenyl-1-picrylhydrazyl scavenging assay), 2.44-fold to 4.12-fold (hydrogen peroxide scavenging assay), 1.34-fold to 3.35-fold (ABTS(+) radical scavenging assay), and also exhibited an increased reducing power. The conjugates also showed excellent lipid peroxidation inhibition abilities in a linoleic acid emulsion system. The conjugates exhibited antimicrobial activity against 15 clinical isolates, two standard methicillin-resistant Staphylococcus aureus (MRSA) and three standard methicillin-susceptible S. aureus strains, as well as eight foodborne pathogens. Additionally, the conjugates showed no cytotoxic activity towards human Chang liver and mouse macrophage RAW264.7 cells. PMID:24262532

Lee, Dae-Sung; Woo, Ji-Young; Ahn, Chang-Bum; Je, Jae-Young

2014-04-01

210

Therapeutic efficacies of chitosan against Pneumocystis pneumonia of immunosuppressed rat.  

PubMed

This study was designed to investigate the therapeutic efficacy of chitosan on Pneumocystis pneumonia (PCP) in immunosuppressed rats. The PCP rat model was established using intramuscular injections of dexamethasone sodium phosphate. To estimate treatment effects of chitosan on rat PCP, weight gain, lung weight, lung weight/body weight (LW/BW) ratio and per cent survival were measured and the HSP70 mRNA expression of Pneumocystis carinii was detected using real-time PCR analysis. Rat lung tissues were stained with HE, and their pathological changes, inflammatory cells and alveolar macrophages were observed by light microscopy. Rat lymphocyte numbers and the concentrations of IL-10, IFN-? and TNF-? were measured by flow cytometry and ELISA analysis. Additionally, the ultrastructure of P. carinii was examined by electron microscopy to evaluate the effects of chitosan on the protist. Our results demonstrated that chitosan has some apparent treatment effects on rat PCP by reducing HSP70 mRNA expression and lung inflammation, increasing the concentrations of IL-10 and IFN-? as well as CD4(+) T-lymphocyte numbers, reducing the CD8(+) T-lymphocyte numbers and the concentration of TNF-? and inducing significant ultrastructural damage to P. carinii. Although its precise therapeutic mechanism has yet to be determined, these results lay a theoretical foundation for PCP chitosan therapy. PMID:24702055

Liu, A-B; Pu, Y; Zheng, Y-Q; Cai, H; Ye, B

2014-07-01

211

Chitosan-nanosilica hybrid materials: Preparation and properties  

NASA Astrophysics Data System (ADS)

The research focuses on the synthesis of novel organic-inorganic hybrid materials based on polysaccharide chitosan and nanosilicas (SiO2, TiO2/SiO2 and Al2O3/SiO2). The chitosan modified nanooxides were obtained by the equilibrium adsorption method. The chitosan adsorption capacities of silica/titania and silica/alumina are higher than of the plain silica due to the additional active sites present on the surfaces of the mixed oxides. The hybrid materials were characterized by low-temperature nitrogen adsorption/desorption, photon correlation spectroscopy (PCS), scanning electron microscopy (SEM), thermogravimetry (TG/DTG) and temperature-programmed desorption with mass spectrometry control (TPD MS) methods. The chitosan treatment only modestly influences the surface area SBET of the nanooxides but the rearrangement of the secondary and tertiary structures (aggregates and agglomerates) results in an enhancement of the mesoporosity and affects the size of the aggregates. The more severe thermodestruction of the polysaccharide desorbing from the modified mixed silicas indicates a stronger interaction between the chitosan and the mixed oxides compared to the silanol groups of the plain silica surface.

Podust, T. V.; Kulik, T. V.; Palyanytsya, B. B.; Gun'ko, V. M.; Tóth, A.; Mikhalovska, L.; Menyhárd, A.; László, K.

2014-11-01

212

Immobilization of Glucose Oxidase in Alginate-Chitosan Microcapsules  

PubMed Central

In order to improve its stability and catalytic rate in flour, the immobilization of glucose oxidase (GOX) was investigated in this work. The enzyme was encapsulated in calcium alginate-chitosan microspheres (CACM) using an emulsification-internal gelation-GOX adsorption-chitosan coating method. The interaction between alginate and chitosan was confirmed by infrared spectroscopy (IR). The resultant CACM in wet state, whose morphology was investigated by scanning electron microscopy (SEM), was spherical with a mean diameter of about 26 ?m. The GOX load, encapsulation efficiency and activity of the CACM-GOX were influenced by concentration of chitosan, encapsulation time and encapsulation pH. The highest total enzymatic activity and encapsulation efficiency was achieved when the pH of the adsorption medium was near the isoelectric point (pI) of GOX, approximately pH 4.0. In addition, the molecular weight of chitosan also evidently influenced the encapsulation efficiency. Storage stabilities of GOX samples were investigated continuously over two months and the retained activity of CACM-GOX was 70.4%, markedly higher than the 7.5% of free enzyme. The results reveal the great potential of CACM-GOX as a flour improver. PMID:21686168

Wang, Xia; Zhu, Ke-Xue; Zhou, Hui-Ming

2011-01-01

213

Chitosan microneedle patches for sustained transdermal delivery of macromolecules.  

PubMed

This paper introduces a chitosan microneedle patch for efficient and sustained transdermal delivery of hydrophilic macromolecules. Chitosan microneedles have sufficient mechanical strength to be inserted in vitro into porcine skin at approximately 250 ?m in depth and in vivo into rat skin at approximately 200 ?m in depth. Bovine serum albumin (BSA, MW=66.5 kDa) was used as a model protein to explore the potential use of chitosan microneedles as a transdermal delivery device for protein drugs. In vitro drug release showed that chitosan microneedles can provide a sustained release of BSA for at least 8 days (approximately 95% of drugs released in 8 days). When the Alexa Fluor 488-labeled BSA (Alexa 488-BSA)-loaded microneedles were applied to the rat skin in vivo, confocal microscopic images showed that BSA can gradually diffuse from the puncture sites to the dermal layer and the fluorescence of Alexa 488-BSA can be observed at the depth of 300 ?m. In addition, encapsulation of BSA within the microneedle matrix did not alter the secondary structure of BSA, indicating that the gentle nature of the fabrication process allowed for encapsulation of fragile biomolecules. These results suggested that the developed chitosan microneedles may serve as a promising device for transdermal delivery of macromolecules in a sustained manner. PMID:23116140

Chen, Mei-Chin; Ling, Ming-Hung; Lai, Kuan-Ying; Pramudityo, Esar

2012-12-10

214

Adsorption characteristics of residual oil on amphiphilic chitosan derivative.  

PubMed

In this study, a novel chitosan-based polymeric surfactant, H-Oleoyl-Carboxymethyl chitosan was used as a coagulation agent for cleaning residual oil. The characteristics of H-Oleoyl-Carboxymethyl chitosan were investigated by FTIR and XRD. And the adsorption capacities of chitosan and H-O-CMCS for removing the residue oil from the wastewater of oil extraction have been investigated. H-O-CMCS exhibited a greater rate than chitosan in cleaning the residual oil from the wastewater of oil extraction at the optimum conditions. Equilibrium study, Langmuir/Freundlich adsorption models and the pseudo first- and second-order kinetic models were applied to describe the mechanism of adsorption experiments. The experimental data fitted well with the Langmuir model and the second-order kinetic model. Regeneration studies, using by the roasting and rinsing method, were undergone for three successive adsorption/desorption processes. H-O-CMCS still retained the residual oil removal capacity after regeneration. PMID:20418634

Sun, Gang Zheng; Chen, Xi Guang; Zhang, Jing; Feng, Chao; Cheng, Xiao Jie

2010-01-01

215

Electroactive chitosan nanoparticles for the detection of single-nucleotide polymorphisms using peptide nucleic acids.  

PubMed

Here we report an electrochemical biosensor that would allow for simple and rapid analysis of nucleic acids in combination with nuclease activity on nucleic acids and electroactive bionanoparticles. The detection of single-nucleotide polymorphisms (SNPs) using PNA probes takes advantage of the significant structural and physicochemical differences between the full hybrids and SNPs in PNA/DNA and DNA/DNA duplexes. Ferrocene-conjugated chitosan nanoparticles (Chi-Fc) were used as the electroactive indicator of hybridization. Chi-Fc had no affinity towards the neutral PNA probe immobilized on a gold electrode (AuE) surface. When the PNA probe on the electrode surface hybridized with a full-complementary target DNA, Chi-Fc electrostatically attached to the negatively-charged phosphate backbone of DNA on the surface and gave rise to a high electrochemical oxidation signal from ferrocene at approximately 0.30 V. Exposing the surface to a single-stranded DNA specific nuclease, Nuclease S1, was found to be very effective for removing the nonspecifically adsorbed SNP DNA. An SNP in the target DNA to PNA made it susceptible to the enzymatic digestion. After the enzymatic digestion and subsequent exposure to Chi-Fc, the presence of SNPs was determined by monitoring the changes in the electrical current response of Chi-Fc. The method provided a detection limit of 1 fM (S/N = 3) for the target DNA oligonucleotide. Additionally, asymmetric PCR was employed to detect the presence of genetically modified organism (GMO) in standard Roundup Ready soybean samples. PNA-mediated PCR amplification of real DNA samples was performed to detect SNPs related to alcohol dehydrogenase (ALDH). Chitosan nanoparticles are promising biomaterials for various analytical and pharmaceutical applications. PMID:18566805

Kerman, Kagan; Saito, Masato; Tamiya, Eiichi

2008-08-01

216

Improving effects of chitosan nanofiber scaffolds on osteoblast proliferation and maturation  

PubMed Central

Osteoblast maturation plays a key role in regulating osteogenesis. Electrospun nanofibrous products were reported to possess a high surface area and porosity. In this study, we developed chitosan nanofibers and examined the effects of nanofibrous scaffolds on osteoblast maturation and the possible mechanisms. Macro- and micro observations of the chitosan nanofibers revealed that these nanoproducts had a flat surface and well-distributed fibers with nanoscale diameters. Mouse osteoblasts were able to attach onto the chitosan nanofiber scaffolds, and the scaffolds degraded in a time-dependent manner. Analysis by scanning electron microscopy further showed mouse osteoblasts adhered onto the scaffolds along the nanofibers, and cell–cell communication was also detected. Mouse osteoblasts grew much better on chitosan nanofiber scaffolds than on chitosan films. In addition, human osteoblasts were able to adhere and grow on the chitosan nanofiber scaffolds. Interestingly, culturing human osteoblasts on chitosan nanofiber scaffolds time-dependently increased DNA replication and cell proliferation. In parallel, administration of human osteoblasts onto chitosan nanofibers significantly induced osteopontin, osteocalcin, and alkaline phosphatase (ALP) messenger (m)RNA expression. As to the mechanism, chitosan nanofibers triggered runt-related transcription factor 2 mRNA and protein syntheses. Consequently, results of ALP-, alizarin red-, and von Kossa-staining analyses showed that chitosan nanofibers improved osteoblast mineralization. Taken together, results of this study demonstrate that chitosan nanofibers can stimulate osteoblast proliferation and maturation via runt-related transcription factor 2-mediated regulation of osteoblast-associated osteopontin, osteocalcin, and ALP gene expression.

Ho, Ming-Hua; Liao, Mei-Hsiu; Lin, Yi-Ling; Lai, Chien-Hao; Lin, Pei-I; Chen, Ruei-Ming

2014-01-01

217

Chitosan-based biosorbents: modification and application for biosorption of heavy metals and radionuclides.  

PubMed

Heavy metal pollution is a serious environmental problem in the world, especially in developing countries. Among different treatment technologies, biosorption seems a promising alternative method. Chitosan-based biosorbents are potential and effective for heavy metal removal from aqueous solution. The preparation and characterization of the natural polymer chitosan, modified chitosan and chitosan composites, and their application for the removal or recovery of toxic heavy metals, precious metals and radionuclides from wastewater were introduced. Chitosan structures and their properties, chitosan modifications (physical conditioning and chemical modification), blends and composites as well as the metal sorption by chitosan-based biosorbents were briefly presented. The metal sorption capacities, influence of intrinsic nature of metal ions, pH and contact time, desorbing agents, isotherm and kinetics models, biosorption mechanisms were discussed. PMID:24461334

Wang, Jianlong; Chen, Can

2014-05-01

218

Carbon nanotube-chitosan modified disposable pencil graphite electrode for vitamin B12 analysis.  

PubMed

A single walled carbon nanotube-chitosan (SWCNT-chitosan) modified disposable pencil graphite electrode (PGE) was used in this study for the electrochemical detection of Vitamin B(12). Electrochemical behaviors of SWCNT-chitosan PGE and chitosan modified PGE were compared by using cyclic voltammetry (CV), square-wave voltammetry (SWV) and electrochemical impedance spectroscopy (EIS) techniques. SWCNT-chitosan modified electrode was also used for the quantification of Vitamin B(12) in pharmaceutical products. The results show that this electrode system is suitable for sensitive Vitamin B(12) analysis giving good recovery results. The surface morphologies of the SWCNT-chitosan PGE, chitosan modified PGE and unmodified PGE were characterized by using scanning electron microscopy (SEM). PMID:21616649

Kuralay, Filiz; Vural, Tayfun; Bayram, Cem; Denkbas, Emir Baki; Abaci, Serdar

2011-10-01

219

In vivo study of chitosan-natural nano hydroxyapatite scaffolds for bone tissue regeneration.  

PubMed

Significant development has been achieved with bioceramics and biopolymer scaffolds in the construction of artificial bone. In the present study, we have developed and compared chitosan-micro hydroxyapatite (chitosan-mHA) and chitosan-nano hydroxyapatite (chitosan-nHA) scaffolds as bone graft substitutes. The biocompatibility and cell proliferation of the prepared scaffolds were checked with preosteoblast (MC3T3-E1) cells. Total Volume (TV), bone volume (BV), bone surface (BS), trabecular thickness (Tb.Th), trabecular number (Tb.N) and trabecular separation (Tb.Sp) were found to be higher in chitosan-nHA than chitosan-mHA scaffold. Hence, we suggest that chitosan-nHA scaffold could be a promising biomaterial for bone tissue engineering. PMID:24705167

Lee, Jong Seo; Baek, Sang Dae; Venkatesan, Jayachandran; Bhatnagar, Ira; Chang, Hee Kyung; Kim, Hui Taek; Kim, Se-Kwon

2014-06-01

220

Chitosan surface enhances the mobility, cytoplasm spreading, and phagocytosis of macrophages.  

PubMed

A chitosan micropattern was prepared on glass by inkjet printing to visualize and compare in real-time macrophage developments on chitosan versus glass during microfluidic culture. The mobility of macrophages on chitosan was significantly higher, since the cells on glass were anchored by the development of podosomes whereas those on chitosan did not form podosomes. The phagocytosis of bacteria by macrophages was considerably more effective on chitosan because of: (1) the macrophages' higher mobility to scavenge nearby bacteria and (2) their cyotoplasm's ability to spread, re-distribute, and recover more freely to engulf the bacteria. Consequently, bacteria growth on chitosan surface was significantly reduced in the presence of macrophages in comparison to that on glass surface, as measured by surface bacteria density and effluent bacteria concentration. These findings suggest the synergistic effect of chitosan as a potential coating material on biomedical implants in promoting macrophage response upon the arrival of opportunistic bacteria. PMID:24632029

Gu, Yexin; Zhang, Wenting; Wang, Hongjun; Lee, Woo Y

2014-05-01

221

Effects of carbon nanotubes in a chitosan/collagen-based composite on mouse fibroblast cell proliferation.  

PubMed

This study investigated the in vitro cytocompatibility of carbon nanotubes (CNTs) in a chitosan/collagen-based composite. Mouse fibroblasts were cultured on the surface of a novel material consisting of CNTs in a chitosan/collagen-based composite (chitosan/collagen+CNTs group). Chitosan/collagen composites without CNTs served as the control material (chitosan/collagen group) and cells cultured normally in tissue culture plates served as blank controls (blank control group). Cell adhesion and proliferation were observed, and cell apoptosis was measured. The doubling time (DT1) of cells was significantly shorter in the chitosan/collagen+CNTs group than in the chitosan/collagen group, and that in the chitosan/collagen group was shorter than in the blank control group. The CNTs in the chitosan/collagen-based composites promoted mouse fibroblast adhesion, producing a distinct cytoskeletal structure. At 24 h after culture, the cytoskeleton of the cells in the chitosan/collagen+CNTs group displayed typical fibroblastic morphology, with clear microfilaments. Cells in the chitosan/collagen group were typically round, with an unclear cytoskeleton. The blank control group even had a few unattached cells. At 4 days after incubation, no early apoptosis of cells was detected in the blank control group, whereas early apoptosis of cells was observed in the chitosan/collagen+CNTs and chitosan/collagen groups. No significant difference in the proportion of living cells was detected among the three groups. After entering the plateau stage, the average cell number in the chitosan/collagen+CNTs group was similar to that in the chitosan/collagen group and significantly smaller than that in the blank control group. Early apoptosis of cells in the blank control group was not detectable. There were significant differences in early apoptosis among the three groups. These results suggest that CNTs in a chitosan/collagen-based composite did not cause significant cytotoxic effects on mouse fibroblasts. Compared with chitosan/collagen composites, early adhesion and proliferation of fibroblasts were increased on chitosan/collagen+CNTs. However, at relatively high cell densities, the CNTs in the chitosan/collagen-based composite might exert an inhibitory effect on mouse fibroblast proliferation by inducing apoptosis. PMID:24052168

Zhao, Wen; Yu, Wenwen; Zheng, Jiawei; Wang, Ying; Zhang, Zhiyuan; Zhang, Dongsheng

2014-01-01

222

The promise of chitosan microspheres in drug delivery systems.  

PubMed

Chitosan is a partially deacetylated polymer obtained from the alkaline deacetylation of chitin, which is a glucose-based, unbranched polysaccharide that occurs widely in nature as the principal component of exoskeletons of crustaceans and insects, as well as of the cell walls of some bacteria and fungi. Chitosan exhibits a variety of physicochemical and biological properties resulting in numerous applications in fields such as waste water treatment, agriculture, fabric and textiles, cosmetics, nutritional enhancement and food processing. In addition to its lack of toxicity and allergenicity, its biocompatibility, biodegradability and bioactivity make it a very attractive substance for diverse applications as a biomaterial in the pharmaceutical and medical fields. This review takes a closer look at the biomedical applications of chitosan microspheres. Based on recent research and existing products, some new and potential future approaches in this fascinating area are discussed. PMID:17489653

Varshosaz, Jaleh

2007-05-01

223

Swelling and surface modification of ultrathin chitosan films  

NASA Astrophysics Data System (ADS)

Chitosan is a biodegradable polysaccharide derived from seashell waste products. The high water absorbency and biocompatibility of chitosan have enabled its use as a hydrogel in specialty biomedical applications. We present the results of several experiments focused on characterizing properties of ultrathin films of chitosan critical to their use in techniques such as wound dressings, medical implants and drug delivery systems. Uniform thin films with thicknesses of 15 to 600 nm and rms roughness of the order of 1 nm were prepared using techniques previously developed in our research group. The swelling of these films in the presence of high humidity has been characterized using reflection ellipsometry, atomic force microscopy and quartz crystal microbalance techniques. The effects of exposure to elevated temperature and UV/ozone (a common surface modification technique) on the surface properties such as hydrophobicity are described.

Murray, Chris

2005-03-01

224

Electrospun nanofibrous chitosan membranes modified with polyethyleneimine for formaldehyde detection.  

PubMed

Here we describe a formaldehyde sensor fabricated by coating polyethyleneimine (PEI) functionalized chitosan nanofiber-net-binary structured layer on quartz crystal microbalance (QCM). The chitosan fibrous substrate comprising nanofibers and spider-web-like nano-nets constructed by a facile electro-spinning/netting process provided an ideal structure for the uniform PEI modification and sensing performance enhancement. Benefiting from the fascinating nanostructure, abundant primary amine groups of PEI, and strong adhesive force to the QCM electrode of PEI-chitosan membranes, the developed formaldehyde sensor presented rapid response and low detection limit (5 ppm) at room temperature. These findings have important implications in fabricating multi-dimensional nanostructures on QCM for gas sensing and chemical analysis. PMID:24751264

Wang, Na; Wang, Xianfeng; Jia, Yongtang; Li, Xiaoqi; Yu, Jianyong; Ding, Bin

2014-08-01

225

Solution blowing of chitosan/PVA hydrogel nanofiber mats.  

PubMed

Both nanofiber mats and hydrogel have their own advantages in wound healing. In this study, a novel hydrogel nanofiber mats were fabricated via solution blowing of chitosan and PVA solution, with various content of ethylene glycol diglycidyl ether (EGDE) as cross-linker. SEM observation showed that the fibers were several hundred nanometers in diameter with smooth surface and distributed randomly forming three-dimensional mats. The structure of the chitosan/PVA nanofibers was examined by FTIR and XPS, and the results showed that the cross-linking reaction occurred between EGDE and the hydroxyl groups. The mats could quickly hydrate in an aqueous environment to form hydrogel. Their value of equilibrate water absorption varied from 680 to 459% various content of EGDE. The nanofiber mats showed good bactericidal activity against Escherichia coli. The chitosan/PVA hydrogel nanofiber mats showed the combination advantages of nanofibrous mats and hydrogel dressing, and were suggested as potential application in wound healing. PMID:24299882

Liu, Ruifang; Xu, Xianlin; Zhuang, Xupin; Cheng, Bowen

2014-01-30

226

N-halamine-based chitosan: preparation, characterization, and antimicrobial function.  

PubMed

Upon chlorine bleach treatment, amino groups in chitosan were transformed into N-halamine structures. The transformation was confirmed by UV/VIS, XPS, DSC, and TGA evaluation and iodimetric titration. The N-halalmine-based chitosan provided total kill of 10(8)-10(9) colony forming units (CFU/mL) of E. coli (gram-negative bacteria) and S. aureus (gram-positive bacteria) in 10 and 60 min, respectively. SEM observations demonstrated that the chlorinated chitosan effectively prevented the formation of bacterial biofilms. The antimicrobial activity and bio film controlling function were stable for longer than 1 month; when the functions were lost due to extensive use and/or prolonged storage, they could be readily recharged by another bleach treatment. The antimicrobial mechanism was also discussed. PMID:17688258

Cao, Zhengbing; Sun, Yuyu

2008-04-01

227

Chitosan based edible films and coatings: a review.  

PubMed

Chitosan is a biodegradable biocompatible polymer derived from natural renewable resources with numerous applications in various fields, and one of which is the area of edible films and coatings. Chitosan has antibacterial and antifungal properties which qualify it for food protection, however, its weak mechanical properties, gas and water vapor permeability limit its uses. This review discusses the application of chitosan and its blends with other natural polymers such as starch and other ingredients for example essential oils, and clay in the field of edible films for food protection. The mechanical behavior and the gas and water vapor permeability of the films are also discussed. References dealing with the antimicrobial behavior of these films and their impact on food protection are explored. PMID:23498203

Elsabee, Maher Z; Abdou, Entsar S

2013-05-01

228

Colon-specific delivery of mesalazine chitosan microspheres.  

PubMed

Mesalazine (5-ASA) is a cyclo-oxygenase inhibitor and anti-inflammatory drug effective in Crohn's disease and ulcerative-colitis. As 5-ASA is rapidly absorbed from the small intestine and it is necessary to develop a colon-specific delivery system for it. Coated chitosan microspheres were used for this purpose by an emulsion-solvent evaporation technique based on a multiple w/o/w emulsion. Four hundred milligrams of chitosan solution (3%) in dilute acetic acid (0.5 M) containing 12% 5-ASA was dispersed into 2 ml solution of cellulose acetate butyrate (CAB) in methylene chloride. The primary induced w/o emulsion was dispersed into a 1% PVA aqueous solution to produce a w/o/w multiple emulsion and was stirred for approximately 2.5 h. The produced microspheres were separated, washed and dried. Release of 5-ASA from microspheres was studied in different pHs 1.2, 7.4, 6.8 and 6.8 in the presence of caecal contents of rat. The average size of microspheres was 200 microm. The highest yield efficiency (80%) was seen in medium molecular weight (MW) chitosan with a 1 : 2 core/coat ratio and the greatest loading efficiency (85%) related to the microspheres of the same type of chitosan but with a 1 : 1 core/coat ratio. Decreasing the coat content and increasing chitosan Mw increased the bioadhesion significantly (p < 0.05). Microspheres of chitosan with medium Mw and 1 : 1 core/coat that showed the greatest release of drug (near 80%) in the presence of caecal secretions with a zero-order mechanism, near zero per cent in pH 1.2 after 2 h, max 20% in pH 7.4 after 3 h and near 60% in pH 6.8 after 8 h seem suitable for site-specific delivery of 5-ASA in vitro. PMID:16801244

Varshosaz, J; Jaffarian Dehkordi, A; Golafshan, S

2006-05-01

229

Biocompatibility assessment of porous chitosan-Nafion and chitosan-PTFE composites in vivo.  

PubMed

Chitosan (CS) is widely used as a scaffold material in tissue engineering. The objective of this study was to test whether porous chitosan membrane (PCSM) coating for Nafion used in implantable sensor reduced fibrous capsule (FC) density and promoted superior vascularization compared with PCSM coating for polytetrafluoroethylene (PTFE). PCSM was fabricated with solvent casting/particulate leaching method using silica gel as porogen and characterized in vitro. Then, PCSM-Nafion and PCSM-PTFE composites were assembled with hydrated PCSM and implanted subcutaneously in rats. The histological analysis was performed in comparison with Nafion and PTFE. Implants were explanted 35, 65, and 100 days after the implantation. Histological assessments indicated that both composites achieved presumed effects of porous coatings on decreasing collagen deposition and promoting angiogenesis. PCSM-PTFE exerted higher collagen deposition by area ratio, both within and outside, compared with that of PCSM-Nafion. Angiogenesis within and outside the PCSM-Nafion both increased over time, but that of the PCSM-PTFE within decreased. PMID:23765695

Liu, Bo-Ji; Ma, Li-Nan; Su, Juan; Jing, Wei-Wei; Wei, Min-Jie; Sha, Xian-Zheng

2014-06-01

230

Immobilization of catalase onto chitosan and cibacron blue F3GA attached chitosan beads  

E-print Network

In this study, chitosan beads (Ch-bead) and cibacron blue F3GA attached chitosan beads (CB-Ch-bead) were prepared. Their characteristics were investigated with experiments of swelling, thermogravimetric analysis and Fourier transform infrared (FTIR) spectroscopic analysis. Catalase (CAT) was immobilized onto these beads. The adsorption isotherms have a Langmuirian shape for Ch-beads and CB-Ch-beads. The CAT adsorption capacity of Ch-beads is higher than that of CB-Ch-beads, but CB-Ch-CAT showed better activity according to the Ch-CAT. The values of apparent Km were found to be 18 and 41 mM for Ch-CAT and CB-Ch-CAT, respectively. However, Vmax values were calculated as 4800 and 14,250 ?mol (mg protein) ?1 min ?1 for Ch-CAT and CB-Ch-CAT, respectively. Furthermore, various characteristics of immobilized catalase, such as the temperature profile, thermal stability, optimum pH, operational stability and storage stability were evaluated. Optimum temperature and optimum pH values were found as 35 ? C and 7.0 for maximum activity of Ch-CAT and CB-Ch-CAT. It was observed that thermal, storage and operational stabilities of the enzyme were increased with immobilization.

S¸enay Akkus Çetinus A; H. Nursevin Öztop A; Dursun Sarayd?n B

2007-01-01

231

Structure and function of enzymes acting on chitin and chitosan.  

PubMed

Enzymatic conversions of chitin and its soluble, partially deacetylated derivative chitosan are of great interest. Firstly, chitin metabolism is an important process in fungi, insects and crustaceans. Secondly, such enzymatic conversions may be used to transform an abundant biomass to useful products such as bioactive chito-oligosaccharides. Enzymes acting on chitin and chitosan are abundant in nature. Here we review current knowledge on the structure and function of enzymes involved in the conversion of these polymeric substrates: chitinases (glycoside hydrolase families 18 & 19), chitosanases (glycoside hydrolase families 8, 46, 75 & 80) and chitin deacetylases (carbohydrate esterase family 4). PMID:21415904

Eijsink, Vincent; Hoell, Ingunn; Vaaje-Kolstada, Gustav

2010-01-01

232

Irradiated PVAl membrane swelled with chitosan solution as dermal equivalent  

NASA Astrophysics Data System (ADS)

Synthetic membranes as dermal equivalent can be applied at in vitro studies for developing new transdermal drugs or cosmetics. These membranes could be composed to mimic the dermis and seed cultivated keratinocytes as epidermal layer on it. The endothelial cells ingrowth to promote neovascularization and fibroblasts ingrowth to promote the substitution of this scaffold by natural components of the dermis. As, they can mimic the scaffold function of dermis; the membranes with biological interaction could be used for in vivo studies as dermal equivalent. For this application, poly(vinyl alcohol) (PVAl) membranes crosslinked by gamma radiation were swelled with chitosan solution. PVAl do not interact with the organism when implanted and is intended to mimic the mechanical characteristics of the dermal scaffold. The chitosan as a biocompatible biosynthetic polysaccharide were incorporated into PVAl membranes to improve the organism response. Degradation of chitosan by the organism occurs preferably by hydrolysis or enzymatic action, for example, by lysozyme. For this purpose the swelling kinetic of PVAl membranes with chitosan solution were performed and it was verified their degradation in vitro. The results showed that the swelling equilibrium of the PVAl membranes with chitosan membranes was reached in 120 h with average swelling of 1730%. After swelling, PVAl and chitosan/PVAl membranes were dried and immersed in phosphate buffer solution pH 5.7 and pH 7.4, with and without lysozyme, as those pH values are the specific physiologic pH for external skin and the general physiological pH for the organism, respectively. It was verified that the pure PVAl membrane did not showed change in their mass during 14 days. PVAl membranes swelled with chitosan solution showed mass decrease from 1 to 14 days inside these solutions. The highest mass decrease was verified at pH 5.7 in phosphate buffer solution without lysozyme. The smallest mass decrease was verified at pH 7.4 in phosphate buffer solution without lysozyme. In general, PVAl membranes swelled with chitosan solution showed a clear mass decrease at pH 5.7.

Rodas, A. C. D.; Ohnuki, T.; Mathor, M. B.; Lugao, A. B.

2005-07-01

233

Chitosan coated cotton gauze for antibacterial water filtration.  

PubMed

Communicable diseases can be transmitted by contaminated water. Water decontamination process is fundamental to eliminate microorganisms. In this work, cotton gauzes were coated with chitosan using an UV-curing process or cationized by introduction of quaternary ammonium groups and tested, in static and dynamic conditions, as water filter for biological disinfection against both Gram-negative and Gram-positive bacteria. Both materials showed good antibacterial activity, in static assessment, instead in dynamic conditions, chitosan treated gauze showed a high antimicrobial efficiency in few seconds of contact time. This composite could be a good candidate for application as biological filter. PMID:24528721

Ferrero, Franco; Periolatto, Monica; Vineis, Claudia; Varesano, Alessio

2014-03-15

234

A single mesoporous ZnO/Chitosan hybrid nanostructure for a novel free nanoprobe type biosensor.  

PubMed

A novel method of fabricating a free probe type nanoscale biosensor is first demonstrated. A free probe type biosensor based on a single one-dimensional (1D) mesoporous ZnO/Chitosan inorganic-organic hybrid nanostructure is constructed. The as-prepared biosensor exhibited excellent biosensing performance and was stable in solution due to its inorganic-organic hybrid structure. The special mesoporous nanostructure with protuberances favors enzymes loading and enhances electrical communication efficiency. The feasibility of employing a single 1D nanostructure as a separate free nanoprobe for biosensing is demonstrated. This kind of free probe type biosensor will not only provides a new tool for micro-targets detection in microcell and enzymatic studies, but also has the potential to be inserted into single cell or other microorganism for biological studies. PMID:23318545

Zhao, Minggang; Huang, Jingyun; Zhou, Yu; Chen, Qi; Pan, Xinhua; He, Haiping; Ye, Zhizhen

2013-05-15

235

Alginate and chitosan functionalization for micronutrient encapsulation.  

PubMed

A new method for encapsulation of micronutrients was successfully developed. The encapsulation matrix consisted of two polymers (alginate and chitosan), which were functionalized by acylation with palmitoyl chloride. The structural modifications of polymers were confirmed by Fourier transform infrared (FTIR) spectroscopy. Beads were formed by ionic gelation, and their mechanical and physical characteristics (puncture strength and deformation, viscoelasticity, water vapor permeability, and rate of gel swelling) were evaluated using beads or films made of bead-forming solutions. Functionalization increased elasticity and water impermeability of polymer films. Stability of selected encapsulated micronutrients (ferrous fumarate, ascorbic acid, and beta-carotene) was also evaluated under two levels of temperature (23 and 45 degrees C) and relative humidity (56 and 100%) for 6 months. Encapsulation strongly increased the stability of micronutrients. No difference was observed in the encapsulated micronutrients' stability between nonfunctionalized and functionalized beads. Finally, a release study in gastrointestinal media was conducted. Results showed that beads were not susceptible to enzymatic and acidic attacks during stomach transit. This research demonstrates the potential of a new encapsulation method to protect bioactive molecules from temperature, moisture, and acidic conditions. PMID:18324770

Han, Jaejoon; Guenier, Anne-Sophie; Salmieri, Stéphane; Lacroix, Monique

2008-04-01

236

Antitumor efficacy of cisplatin-loaded glycol chitosan nanoparticles in tumor-bearing mice.  

PubMed

To make a tumor targeting nano-sized drug delivery system, biocompatible and biodegradable glycol chitosan (M(w)=250 kDa) was modified with hydrophobic cholanic acid. The resulting hydrophobically modified glycol chitosans (HGCs) that formed nano-sized self-aggregates in an aqueous medium were investigated as an anticancer drug carrier in cancer treatment. Insoluble anticancer drug, cisplatin (CDDP), was easily encapsulated into the hydrophobic cores of HGC nanoparticles by a dialysis method, wherein the drug loading efficiency was about 80%. The CCDP-encapsulated HGC (CDDP-HGC) nanoparticles were well-dispersed in aqueous media and they formed a nanoparticles structure with a mean diameter about 300-500 nm. As a nano-sized drug carrier, the CDDP-HGC nanoparticles released the drug in a sustained manner for a week and they were also less cytotoxic than was free CDDP, probably because of sustained release of CDDP from the HGC nanoparticles. The tumor targeting ability of CDDP-HGC nanoparticles was confirmed by in vivo live animal imaging with near-infrared fluorescence Cy5.5-labeled CDDP-HGC nanoparticles. It was observed that CDDP-HGC nanoparticles were successfully accumulated by tumor tissues in tumor-bearing mice, because of the prolonged circulation and enhanced permeability and retention (EPR) effect of CDDP-HGC nanoparticles in tumor-bearing mice. As expected, the CDDP-HGC nanoparticles showed higher antitumor efficacy and lower toxicity compared to free CDDP, as shown by changes in tumor volumes, body weights, and survival rates, as well as by immunohistological TUNEL assay data. Collectively, the present results indicate that HGC nanoparticles are a promising carrier for the anticancer drug CDDP. PMID:18234388

Kim, Jong-Ho; Kim, Yoo-Shin; Park, Kyeongsoon; Lee, Seulki; Nam, Hae Yun; Min, Kyung Hyun; Jo, Hyung Gon; Park, Jae Hyung; Choi, Kuiwon; Jeong, Seo Young; Park, Rang-Woon; Kim, In-San; Kim, Kwangmeyung; Kwon, Ick Chan

2008-04-01

237

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

PubMed Central

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

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

2014-01-01

238

Direct writing of chitosan scaffolds using a robotic system  

Microsoft Academic Search

Purpose – This paper aims to present a novel rapid prototyping (RP) fabrication methods and preliminary characterization for chitosan scaffolds. Design – A desktop rapid prototyping robot dispensing (RPBOD) system has been developed to fabricate scaffolds for tissue engineering (TE) applications. The system is a computer-controlled four-axis machine with a multiple-dispenser head. Neutralization of the acetic acid by the sodium

Li Geng; Wei Feng; Dietmar W. Hutmacher; Yoke San Wong; Han Tong Loh; Jerry Y. H. Fuh

2005-01-01

239

Virus adsorption of water-stable quaternized chitosan nanofibers.  

PubMed

The burden of unsafe drinking water is responsible for millions of deaths each year. To relieve this burden, we are in search of an inexpensive material that can adsorb pathogens from drinking water. In this pursuit, we have studied the natural carbohydrate, chitosan. To impart virus removal features, chitosan has been functionalized with a quaternary amine to form quaternized chitosan N-[(2-hydroxyl-3-trimethylammonium) propyl] chitosan (HTCC). HTCC can be electrospun into nanofibers with the non-ionogenic polyvinyl alcohol (PVA), creating a high surface area mat. High surface area is a major requirement for effective adsorption processes. HTCC is antiviral and antimicrobial, making it a good material for water purification. However, HTCC dissolves in water. We have explored the parameters to crosslink the nanofibers with glutaraldehyde. We have imparted water stability so there is a maximum of 30% swelling of the fibers after 6h in water. The water stable fibers retain their ability to adsorb virus, as shown for an enveloped and nonenveloped virus. HTCC now has the potential to be incorporated into a microfiltration membrane that can remove viruses. This could create an inexpensive, low pressure filtration membrane for drinking water purification. PMID:24561959

Mi, Xue; Vijayaragavan, K Saagar; Heldt, Caryn L

2014-03-31

240

Preparation and properties of chitosan chondroitin sulfate complex microcapsules.  

PubMed

The chitosan (CHS) chondroitin sulfate (CS) complex microcapsules were prepared by emulsion-chemical crosslink method, with the chitosan and chondroitin sulfate as the wall materials and the low molecular weight heparin (LMWH) as the core materials. The microcapsules were characterized by Fourier transform infrared (IR) spectrometry, scanning electron microscope (SEM), size distribution and thermal analysis. The in vitro drug release behavior of the microcapsules was studied by spectrophotometry. The SEM and size distribution showed that the microcapsules were in the spherical form mostly in the size range of 20-80 microm. The IR spectrum indicated that there were electrostatic interactions between chitosan and chondroitin sulfate, with the sulfate group and free carboxyl group reacted with the amino groups of chitosan. The DSC result showed that the wall materials could protect the core materials of the microcapsules. The results of the release kinetics experiments of the microcapsules showed that the drug released slightly faster in acid media than in alkali ones. PMID:18440788

Sui, Weiping; Huang, Liangliang; Wang, Jun; Bo, Qibing

2008-08-01

241

Effects of Steam Sterilization on Thermogelling Chitosan-Based Gels  

E-print Network

sterilization bioindicator Bacillus stearothermophilus, the bacteria could rapidly grow after separation fromEffects of Steam Sterilization on Thermogelling Chitosan-Based Gels Claire Jarry,1 Cyril Chaput,2 of this work were to characterize the effect of steam sterilization on the in vitro and in vivo end perfor

Buschmann, Michael

242

Atomic force microscopy of gastric mucin and chitosan mucoadhesive systems.  

PubMed Central

Atomic force microscopy has been utilized to probe, at a molecular level, the interaction between purified pig gastric mucin (PGM) and a mucoadhesive cationic polymer, chitosan (sea cure 210+), with a low degree (approx. 11%) of acetylation. Images were produced detailing the structures of both PGM and chitosan in 0.1 M acetate buffer (pH 4.5), followed by the complex of the two structures in the same buffer. PGM in 0.1 M acetate buffer revealed long linear filamentous structures, consistent with earlier electron microscopy and scanning tunnelling micoscopy studies. The chitosan molecules also adopted a linear conformation in the same buffer, although with a smaller average length and diameter. They appeared to adopt a stiff-coil conformation consistent with earlier hydrodynamic measurements. The complexes formed after mixing PGM and chitosan together revealed large aggregates. In 0.1 M ionic strength buffer they were of the order of 0.7 microm in diameter, consistent with previous electron microscopy studies. The effect of ionic strength of the buffer on the structure of the complex was also studied and, together with molecular hydrodynamic data, demonstrates that the interaction is principally electrostatic in nature. PMID:10839986

Deacon, M P; McGurk, S; Roberts, C J; Williams, P M; Tendler, S J; Davies, M C; Davis, S S; Harding, S E

2000-01-01

243

Preparation and Evaluation of Carrageenan/Chitosan Multilayer Beads  

NASA Astrophysics Data System (ADS)

Polyelectrolyte complexes (PECs) of chitosan and carrageenan were used for preparation of multilayered microbeads. The optimal conditions of complex formation—pH and molar ratio between the polyelectrolyte partners, were preliminary investigated by viscometry. It was found that the yield of the complex is the highest at pH 5 where both of the partners were highly charged. Chitosan was used as a core of the beads and carrageenan/chitosan multilayers were deposited by layer-by-layer technique. Swelling and stability of the beads were investigated in dependence on the pH of the media. The multilayer deposition let to modification of the swelling behaviour—the equilibrium degree of swelling decreased at pH 3 and increased at basic pH. These changes were attributed to the polyelectrolyte properties of carrageenan/chitosan PECs—the impact of the effective charges in PECs network. Mehanical properties of the swelled beads were evaluated by Stable Micro Systems table penetrometer, with flat-plate compression test. The test was carried out with low deformation speed, until the full rupture. The diameter of measure cylinder was chosen to be bigger then the diameter of beads. The different swellings caused differences in elastic properties of the multilayered beads.

Marudova, M. G.; Zsivanovits, G.; Popchev, I. G.; Petrovska, I. P.

2010-01-01

244

Mechanical properties of paper sheets coated with chitosan nanoparticle  

NASA Astrophysics Data System (ADS)

Chitosan were selected as cellulose raw material to prepare coating solutions. The morphology, physical characteristics and chemical surface properties of the coatings are discussed in this paper. Different concentrations of chitosan (1-5% w/w) and deposited solution layer (0.5-1.00 ?m) were used to obtain coated papers with thicknesses varying between 0.062-0.068 ?m. The percentages of coating agent impregnated inside paper were also calculated from the apparent density of coated paper and the density of self-supported films prepared in the same conditions but deposited on an inert and smooth Plexiglass support. These percentages of impregnation ranged from 4.8 to 63.3% and increased as following: chitosan < chitosan nanoparticle. The resulting absorption rates indicated significant differences as a function of the nature of coating agent and confirmed results obtained for the percentage of impregnation. To explain differences in the behaviour of coating solutions, it was finally concluded that not only their viscosity must be taken into account but also their affinity toward paper.

Fithriyah, Nurul Hidayati; Erdawati

2014-03-01

245

Thermodynamic properties of chitosan dodecahydro- closo-dodecaborate  

NASA Astrophysics Data System (ADS)

Combustion enthalpies of chitosan dodecahydro- closo-dodecaborate corresponding to -13194 kJ/mol are measured via combustion in an AKS-3M automatic calorimeter. The standard enthalpy of formation corresponding to -5223 kJ/mol is calculated from the resulting experimental data.

Saldin, V. I.; Buznik, V. M.; Mikhailov, Yu. M.; Ganina, L. V.

2014-03-01

246

Chitosan and its antimicrobial potential - a critical literature survey  

PubMed Central

Summary Chitosan, an aminopolysaccharide biopolymer, has a unique chemical structure as a linear polycation with a high charge density, reactive hydroxyl and amino groups as well as extensive hydrogen bonding. It displays excellent biocompatibility, physical stability and processability. The term ‘chitosan’ describes a heterogenous group of polymers combining a group of physicochemical and biological characteristics, which allow for a wide scope of applications that are both fascinating and as yet uncharted. The increased awareness of the potentials and industrial value of this biopolymer lead to its utilization in many applications of technical interest, and increasingly in the biomedical arena. Although not primarily used as an antimicrobial agent, its utility as an ingredient in both food and pharmaceutical formulations lately gained more interest, when a scientific understanding of at least some of the pharmacological activities of this versatile carbohydrate began to evolve. However, understanding the various factors that affect its antimicrobial activity has become a key issue for a better usage and a more efficient optimization of chitosan formulations. Moreover, the use of chitosan in antimicrobial systems should be based on sufficient knowledge of the complex mechanisms of its antimicrobial mode of action, which in turn would help to arrive at an appreciation of its entire antimicrobial potential. PMID:21261913

Raafat, Dina; Sahl, Hans-Georg

2009-01-01

247

Chitosan/alkylethoxy carboxylates: a surprising variety of structures.  

PubMed

In this work, we present a comprehensive structural characterization of long-term stable complexes formed by biopolycation chitosan and oppositely charged nonaoxyethylene oleylether carboxylate. These two components are attractive for many potential applications, with chitosan being a bioderived polymer and the surfactant being ecologically benign and mild. Experiments were performed at different mixing ratios Z (ratio of the nominal charges of surfactant/polyelectrolyte) and different pH values such that the degree of ionization of the surfactant is largely changed whereas that of chitosan is only slightly affected. The structural characterization was performed by combining static and dynamic light scattering (SLS and DLS) and small-angle neutron scattering (SANS) to cover a large structural range. Highly complex behavior is observed, with three generic structures formed that depend on pH and the mixing ratio, namely, (i) a micelle-decorated network at low Z and pH, (ii) rodlike complexes with the presence of aligned micelles at medium Z and pH, and (iii) compacted micellar aggregates forming a supraaggregate surrounded by a chitosan shell at high Z and pH. Accordingly, the state of aggregation in these mixtures can be tuned structurally over quite a range only by rather small changes in pH. PMID:24490632

Chiappisi, Leonardo; Prévost, Sylvain; Grillo, Isabelle; Gradzielski, Michael

2014-02-25

248

Chitosan Biotinylation and Electrodeposition for Selective Protein Assembly  

E-print Network

materials for the spatially selective assembly of proteins is described. Specifically, the stimuli- streptavidin binding. Biotinylated chitosan retains its stimuli-responsive properties and is capable- technology Institute, 5115 Plant Sciences Building, College Park, MD 20742, USA Fax: þ1 301 314 9075; E

Rubloff, Gary W.

249

Polymer enhanced ultrafiltration of mercury using chitosan impregnated ceramic membrane  

Microsoft Academic Search

This work reports the removal of mercury from synthetic wastewater by polymer enhanced ultrafiltration (PEUF). A ceramic membrane was prepared from locally available clay and the membrane surface was impregnated using chitosan to reduce the pore size to ultrafiltration range. The average pore size of the membrane was determined from air permeability data and found to be 12 nm. Polyvinyl

Somen Jana; M. K. Purkait; Kaustubha Mohanty

2012-01-01

250

Abatement of Azo Dye from Wastewater Using Bimetal-Chitosan  

PubMed Central

We introduce a new adsorbent, bimetallic chitosan particle (BCP) that is successfully synthesized and applied to remove the orange II dye from wastewater. The effects of pH, BCP quantity, and contact time are initially verified on the basis of the percentage of orange II removed from the wastewater. Experimental data reveal that the Cu/Mg bimetal and chitosan have a synergistic effect on the adsorption process of the adsorbate, where the dye adsorption by Cu/Mg bimetal, chitosan alone, and bimetal-chitosan is 10, 49, and 99.5%, respectively. The time required for the complete decolorization of orange II by 1?mg/L of BCP is 10?min. The Langmuir model is the best fit for the experimental data, which attains a maximum adsorption capacity of 384.6?mg/g. The consideration of the kinetic behavior indicates that the adsorption of orange II onto the BCP fits best with the pseudo-second-order and Elovich models. Further, the simulated azo dye wastewater can be effectively treated using a relatively low quantity of the adsorbent, 1?mg/L, within a short reaction time of 20?min. Overall, the use of BCP can be considered a promising method for eliminating the azo dye from wastewater effectively. PMID:24348163

Asgari, Ghorban; Farjadfard, Sima

2013-01-01

251

[Study on immune efficacy of Newcastle disease chitosan microsphere vaccine].  

PubMed

Newcastle disease is an acute and highly contagious disease caused by Newcastle disease virus (NDV), one of which does great harms to the poultry industry. The most basic measure of controlling New Castle disease is to alid vaccine, now we usually use La Sota live vaccine and inactivated NDV vaccine, but these two vaccines both have more or less limitation. It can produce higher mucosal immunity titers by taking vaccine orally, meanwhile it can induce humoral and cell-mediated immune response and mucosal immunity strongly. Therefore, it becomes the focus of the research, which prepare new pattern vaccines taking orally. NDV chitosan microsphere vaccine was prepared using chitosan as capsule wall material, NDV as core material, glutaraldehyde as cross-linking material, and its even particle diameter was 5.83um, and its surface was smooth and glossy, no obviously pore space, yellow brown pykno-ball, and its safety and potency were evaluated. The SPF chickens were immunized with NDV chitosan microsphere vaccine, La Sota live vaccine and inactivated NDV vaccine respectively. To evaluate vaccine's immune efficacy, using MTT to measure lymphocytes proliferation in vitro, using HI to measure serum special IgG and using ELISA tests to detect mucosal sIgA titers. The results show that NDV chitosan microsphere vaccine was safe, could induce humoral and cell-mediated immune response and mucosal immunity strongly. The results of the potency tests conformed that the vaccine could produce good protective effect. PMID:17944374

Zhai, Rong-ling; Xu, Huai-ying; Wang, You-ling; Qin, Zhuo-ming; Jiang, Shi-jin

2007-08-01

252

Enriched fluoride sorption using alumina/chitosan composite.  

PubMed

Alumina possesses an appreciable defluoridation capacity (DC) of 1566 mg F(-)/kg. In order to improve its DC, it is aimed to prepare alumina polymeric composites using the chitosan. Alumina/chitosan (AlCs) composite was prepared by incorporating alumina particles in the chitosan polymeric matrix, which can be made into any desired form viz., beads, candles and membranes. AlCs composite displayed a maximum DC of 3809 mg F(-)/kg than the alumina and chitosan (52 mg F(-)/kg). The fluoride removal studies were carried out in batch mode to optimize the equilibrium parameters viz., contact time, pH, co-anions and temperature. The equilibrium data was fitted with Freundlich and Langmuir isotherms to find the best fit for the sorption process. The calculated values of thermodynamic parameters indicate the nature of sorption. The surface characterisation of the sorbent was performed by FTIR, AFM and SEM with EDAX analysis. A possible mechanism of fluoride sorption by AlCs composite has been proposed. Suitability of AlCs composite at field conditions was tested with a field sample taken from a nearby fluoride-endemic village. This work provides a potential platform for the development of defluoridation technology. PMID:20144851

Viswanathan, Natrayasamy; Meenakshi, S

2010-06-15

253

Chitosan as template for the synthesis of ceria nanoparticles  

SciTech Connect

Graphical abstract: Cerium oxide nanoparticles with cubic fluorite structure were prepared using chitosan as template, cerium nitrate as a starting material and sodium hydroxide as a precipitating agent. Calcinated powders at 350 {sup o}C contain agglomerated particles with average particle size of {approx}4 nm, very high porosity and foam-like morphology formed by open and close pores. Highlights: {yields} Pure CeO{sub 2} nanoparticles can take place using chitosan as template. {yields} A porous material was obtained. {yields} Blueshifts in the ultraviolet absorption spectra have been observed in cerium oxide nanocrystallites. -- Abstract: Cerium oxide (CeO{sub 2}), nanoparticles were prepared using chitosan as template, cerium nitrate as a starting material and sodium hydroxide as a precipitating agent. The resultant ceria-chitosan spheres were calcined at 350 {sup o}C. The synthesized powders were characterized by, XRD, HRTEM, UV-vis, FTIR, and TG-DTA. The average size of the nanoparticles obtained was {approx}4 nm and BET specific surface area {approx}105 m{sup 2} g{sup -1}. Blueshifts in the ultraviolet absorption spectra have been observed in cerium oxide nanocrystallites. The band-gap was found to be 4.5 eV. The blueshifts are well explained for diameters down to less than a few nanometers by the change in the electronic band structure.

Sifontes, A.B., E-mail: asifonte@ivic.gob.ve [Centro de Quimica, Instituto Venezolano de Investigaciones Cientificas, Caracas 1020-A (Venezuela, Bolivarian Republic of); Gonzalez, G.; Ochoa, J.L. [Centro de Ingenieria, Instituto Venezolano de Investigaciones Cientificas, Caracas 1020-A (Venezuela, Bolivarian Republic of)] [Centro de Ingenieria, Instituto Venezolano de Investigaciones Cientificas, Caracas 1020-A (Venezuela, Bolivarian Republic of); Tovar, L.M.; Zoltan, T. [Centro de Quimica, Instituto Venezolano de Investigaciones Cientificas, Caracas 1020-A (Venezuela, Bolivarian Republic of)] [Centro de Quimica, Instituto Venezolano de Investigaciones Cientificas, Caracas 1020-A (Venezuela, Bolivarian Republic of); Canizales, E. [PDVSA, Intevep, Caracas 1020-A (Venezuela, Bolivarian Republic of)] [PDVSA, Intevep, Caracas 1020-A (Venezuela, Bolivarian Republic of)

2011-11-15

254

Influence of grape pomace extract incorporation on chitosan films properties.  

PubMed

Chitosan has been studied as a renewable polymer to form edible films allowing the incorporation of functional compounds. The aim of this work was to evaluate the effects in the chitosan films properties of the incorporation of grape pomace extracts: 0.15% of hot water extract (mainly polysaccharides), 0.15 and 0.3% of chloroform extract (wax), and 0.3 and 0.75% of n-hexane extract (oil). The evaluation of the surface morphology revealed that the films with the aqueous extract had the most homogeneous and smoother topography. The incorporation of higher proportion of wax and oil led to changes in mechanical properties of the films, namely lower resistance and stiffness. The chitosan-based films with 0.75% oil demonstrated a 75% decrease of solubility in water, due to their hydrophobicity, as confirmed by the contact angle and surface free energy measurements. The hydrophobic films showed higher antioxidant capacity in organic medium (ABTS and DPPH assays) whereas the most hydrophilic films showed an improvement in FRAP and reducing power assays. Therefore, all the chitosan-based films prepared by incorporation of these grape pomace extracts are promising for food shelf life extension. PMID:25256511

Ferreira, Andreia S; Nunes, Cláudia; Castro, Alichandra; Ferreira, Paula; Coimbra, Manuel A

2014-11-26

255

Production of chitosan pellets by extrusion\\/spheronization  

Microsoft Academic Search

Chitosan pellets were successfully prepared using the extrusion\\/spheronization technology. Microcrystalline cellulose was used as additive in concentrations from 70 to 0%. The powder mixtures were extruded using water and diluted acetic acid solution in different powder to liquid ratios. The effects on bead formation using water and different acetic acid concentrations and solution quantities were analysed. Also, the morphological and

H. Steckel; F. Mindermann-Nogly

2004-01-01

256

Electrolytic deposition of calcium phosphate/chitosan coating on titanium alloy: growth kinetics and influence of current density, acetic acid, and chitosan.  

PubMed

Electrolytically deposited calcium phosphate/chitosan coating demonstrated good bone marrow stromal cell attachment. The aim of this study was to understand the coating's growth kinetics as well as the effects of current density, acetic acid, and chitosan on the coating's formation. The scanning electron micrographs found that calcium phosphate crystals homogeneously distributed into chitosan aggregates as early as 30 min. X-ray diffraction patterns and Fourier transform infrared spectra demonstrated that the coating experienced a compositional conversion from octacalcium phosphate to carbonate apatite during the deposition process. Electric current influenced the deposition. Higher current density accelerated the process and induced faster and more chitosan deposition. Both acetic acid and chitosan were found to inhibit calcium phosphate deposition. Chitosan was thought to induce stronger effects than acetic acid did. Furthermore, the inhibitive effect related to their concentration in the electrolyte. When chitosan concentration increased to a certain degree, this inhibitive effect not only affected calcium phosphate deposition, but also affected its own deposition. The chitosan content within the hybrid coating was small, which could be verified through Raman spectrum. At the same time, no clear evidence of chemical reactions could be found between these two components. We considered that both components were just naturally wrapped to form as a whole. PMID:16278873

Wang, Jiawei; van Apeldoorn, Aart; de Groot, Klaas

2006-03-01

257

Effect of chitosan molecular weight on the functional properties of chitosan-maltose Maillard reaction products and their application to fresh-cut Typha latifolia L.  

PubMed

The objective was to evaluate antimicrobial, antioxidant and copper-chelating activities of Maillard reaction products (MRP) prepared from maltose and different molecular weight chitosan, and their effects on preservation of fresh-cut Typha latifolia L. (TLL). LMRP (maltose and low molecular weight chitosan MRP) showed the highest browning and UV absorbance as well as fluorescence intensity. The DPPH radical scavenging activity, reducing power and copper-chelating activity of chitosan-maltose MRP varied depending on the chitosan molecular weight. HMRP (maltose-high molecular weight chitosan MRP) exhibited better effects on inhibiting PPO activity and discoloration, alleviating declines of total soluble solids and ascorbic acid content of fresh-cut TLL. LMRP and MMRP (maltose-medium molecular weight chitosan MRP) effectively decreased weight loss and maintained firmness of TLL, respectively. These results indicated that molecular weight of chitosan had a great impact on the functional properties of chitosan-maltose MRP and their application to be used as a preservative. PMID:24507336

Li, Song-Lin; Lin, Jing; Chen, Xiao-Ming

2014-02-15

258

The synthesis, self-assembling, and biocompatibility of a novel O-carboxymethyl chitosan cholate decorated with glycyrrhetinic acid.  

PubMed

O-carboxymethyl chitosan (OCMC) was firstly decorated with cholic acid (CA) to acquire an amphiphilic polymer under alkaline condition. Then glycyrrhetinic acid (GA) was conjugated to the polymer via a succinate linker and finally treated with NaCO3 solution to obtain new conjugates for potential liver targeted delivery. These conjugates formed uniform aggregates with low critical aggregation concentrations (0.028-0.079 mg/mL) in PBS. The average diameter of cholic acid modified carboxymethyl chitosan (CMCA) aggregates (110-257 nm) decreased with the increase of CA substitution degree and became slightly larger after GA modification. Negative zeta potential (-15 mV) of GA decorated CMCA (GA-CMCA) revealed that the formation of negatively charged shells and spherical morphology was observed under transmission electron microscopy. Furthermore, hemolysis test, in vitro cytotoxicity assay and cellular uptake study all demonstrated the safety and feasibility of these conjugates as a promising carrier for liver targeted drug delivery. PMID:25037412

Du, Hongliang; Yang, Xiaoye; Pang, Xin; Zhai, Guangxi

2014-10-13

259

Chitosan-starch nanocomposite particles as a drug carrier for the delivery of bis-desmethoxy curcumin analog.  

PubMed

The conventional drug delivery system has serious limitations such as lack of target specificity, altered effects and diminished potency. These limitations can be overcome by using biocompatible polymer as an effective drug delivery system. In this study, bis-demethoxy curcumin analog loaded Chitosan-starch (BDMCA-CS) nanocomposite particles were developed using different ratios of Chitosan and starch (3:1, 1:1 & 1:3) by ionic gelation method. The entrapment efficiency and drug loading capacity were found to be high for the formulation with the ratio 3:1 of BDMCA:CS. Physical characterization of the nanocomposite particles was determined using DLS and FTIR. The morphology of the BDMCA-CS nanocomposite particles were found to be spherical and regular by SEM analysis. In-vitro drug release profile of the BDMCA-CS nanocomposite particles showed a very slow and sustained diffusion controlled release of the drug. The cancer cells targeting ability of the BDMCA-CS nanocomposite particles were confirmed by performing MTT assay on MCF-7 breast cancer cell lines and VERO cell lines. PMID:25263878

Subramanian, Sindhuja Bala; Francis, Arul Prakash; Devasena, Thiyagarajan

2014-12-19

260

Optimization of chitosan treatments for managing microflora in lettuce seeds without affecting germination.  

PubMed

Many studies have focused on seed decontamination but no one has been capable of eliminating all pathogenic bacteria. Two objectives were followed. First, to assess the in vitro antimicrobial activity of chitosan against: (a) Escherichia coli O157:H7, (b) native microflora of lettuce and (c) native microflora of lettuce seeds. Second, to evaluate the efficiency of chitosan on reducing microflora on lettuce seeds. The overall goal was to find a combination of contact time and chitosan concentration that reduces the microflora of lettuce seeds, without affecting germination. After treatment lettuce seeds presented no detectable microbial counts (<10(2)CFU/50 seeds) for all populations. Moreover, chitosan eliminated E. coli. Regardless of the reduction in the microbial load, a 90% reduction on germination makes imbibition with chitosan, uneconomical. Subsequent treatments identified the optimal treatment as 10 min contact with a 10 g/L chitosan solution, which maintained the highest germination percentage. PMID:23218371

Goñi, M G; Moreira, M R; Viacava, G E; Roura, S I

2013-01-30

261

Lipase entrapment in PVA/Chitosan biodegradable film for reactor coatings.  

PubMed

This study reports the development and characterization of novel biodegradable film, based on chitosan and polyvinyl alcohol containing lipase entrapped. The films showed a thickness of 70.4 and 79 ?m to PVA/Chitosan and PVA/Chitosan/Lipase, respectively. The entrapment of lipase in PVA/Chitosan film resulted in increasing of 69.4% tensile strength (TS), and 52.4% of elongation. SEM images showed the formation of a continuous film, without pores or cracks. The lipase entrapment efficiency was estimated in 92% and the films were repeatedly used for 25 hydrolytic cycles, maintaining 62% of initial activity. The PVA/Chitosan/Lipase film was used for olive oil hydrolysis of high performance. These results indicate that PVA/Chitosan/Lipase is a promising material for biotechnology applications such as triacylglycerol hydrolysis and biodiesel production. PMID:23827626

Batista, Karla A; Lopes, Flavio Marques; Yamashita, Fabio; Fernandes, Kátia Flávia

2013-04-01

262

Preparation of extruded polyethylene/chitosan blends compatibilized with polyethylene-graft-maleic anhydride.  

PubMed

Novel films of polyethylene and chitosan were obtained using extrusion. These polymers have interesting properties, and processing them with methods that are of high use in the industry, such as the extrusion method, can have a significant effect on the potential applications of these materials. The individual materials were thermally characterized; after this, extruded films of low density polyethylene and chitosan mixtures were prepared with the addition of polyethylene-graft-maleic anhydride as a compatibilizer for the blends, and glycerol, as a plasticizer for chitosan. The use of compatibilizer and plasticizer agents improved the processability and compatibility of the mixtures, as well as their mechanical properties, as revealed by mechanical property measurements and scanning electron microscopy. It was possible to prepare blends with a maximum chitosan content of 20 wt%. The material stiffness increased with the increase of chitosan in the sample. FTIR studies revealed the existence of an interaction between the compatibilizer and chitosan. PMID:24299879

Quiroz-Castillo, J M; Rodríguez-Félix, D E; Grijalva-Monteverde, H; Del Castillo-Castro, T; Plascencia-Jatomea, M; Rodríguez-Félix, F; Herrera-Franco, P J

2014-01-30

263

Synthesis and antifungal properties of (4-tolyloxy)-pyrimidyl-?-aminophosphonates chitosan derivatives.  

PubMed

A novel class of ?-aminophosphonate chitosan derivatives was investigated. These chitosan derivatives consist of (4-tolyloxy)-pyrimidyl-dimethyl-?-amino-phosphonate chitosan (?-ATPMCS) and (4-tolyloxy)-pyrimidyl-diethyl-?-aminophosphonate chitosan (?-ATPECS). Their structures were well defined. Antifungal activity of them against some crop-threatening pathogenic fungi was tested in vitro. The derivatives were found to have a broad-spectrum antifungal activity that was obviously enhanced compared with chitosan. At 250 mg/L, both ?-ATPMCS and ?-ATPECS even inhibited growth of Phomopsis asparagi (Sacc.) (P. asparagi) and Fusarium oxysporum (F. oxysporum) at 100%, which was even stronger than polyoxin whose antifungal index was 37.2% and 32.1%, respectively. Additionally, the initial mechanism of the chitosan derivatives in F. oxysporum model was studied. It was found that the derivatives may have an effect on membrane permeability of the fungi. The results demonstrated the derivatives may serve as attractive candidates in crop protection. PMID:24183805

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

2014-02-01

264

Synthesis of hybrid polymer networks of irradiated chitosan/poly(vinyl alcohol) for biomedical applications  

NASA Astrophysics Data System (ADS)

Hybrid polymer network (HPN) of chitosan (CS) with poly(vinyl alcohol) (PVA) was prepared by using radiation degraded chitosan. The chemical structure of chitosan promoted chain scission reactions upon irradiation which lowered its molecular weight and also changed its hydrophilic balance. The effect of molecular weight and hydrophilicity of irradiated chitosan on structural, thermal and surface properties of the HPN were studied. The increased hydrophilicity of irradiated chitosan lowered the crystallinity of the HPN. The endothermic peak was shifted towards higher temperatures in HPN having irradiated chitosan. The decreased value of contact angle with increasing dose, further confirmed the increased hydrophilicity of the HPN. The cytotoxicity results of HPN showed the viability of human fibroblast cells and their non-toxic nature making it suitable for tissue engineering and other biomedical applications.

Islam, Atif; Yasin, Tariq; Rehman, Ihtesham ur

2014-03-01

265

Fabrication and characterization of chitosan-collagen crosslinked membranes for corneal tissue engineering.  

PubMed

This article describes a chitosan-collagen composite membrane as corneal tissue-engineering biomaterials. The membrane was prepared by dissolving the chitosan into collagen with the weight ratio of 0, 15, 30, 45, 60, and 100%, followed by crosslinked with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide. Mechanical properties, contact angles, and optical transmittance were determined and compared between chitosan membrane and crosslinking composite membrane. As a result, the optical transparency and mechanical strength of the chitosan-collagen membranes were significantly better than that of the sample of chitosan. In addition, in vitro cell culture studies revealed that the collagen has no negative effect on the cell morphology, viability, and proliferation and possess good biocompatibility. Overall, the dendrimer crosslinked chitosan-collagen composite membranes showed promising properties that suggest that these might be suitable biomaterials for corneal tissue-engineering applications. PMID:25299624

Li, Weichang; Long, Yuyu; Liu, Yang; Long, Kai; Liu, Sa; Wang, Zhichong; Wang, Yingjun; Ren, Li

2014-12-01

266

Characterisation of gamma irradiated chitosan/pHEMA membranes for biomedical purposes  

NASA Astrophysics Data System (ADS)

As a polysaccharide of natural origin, chitosan has the inherent properties of being biocompatible, biodegradable, and non-toxic. These properties make chitosan an ideal candidate for based backbone in copolymeric matrices for use in biomedical applications. Poly(hydroxyethyl methacrylate) is a synthetic hydrogel which possesses a high mechanical strength. The conjunction of these two components results in a new matrix that combines the useful properties of the synthetic pHEMA and natural chitosan. In this work chitosan/pHEMA membranes were obtained and ?-irradiated under nitrogen atmosphere. The effect of various synthesis conditions on the chemical, physical and biological properties was evaluated. The chitosan/pHEMA membranes were characterised using FTIR spectroscopy, scanning electron microscopy and thermal analysis techniques. Its hydration capacity and its antimicrobial properties were also determined. The obtained results showed that the hydration capacity decreases in the irradiated membranes. It was also found that chitosan/pHEMA membranes present good barrier properties against microbes.

Casimiro, M. H.; Leal, J. P.; Gil, M. H.

2005-07-01

267

PAMAM conjugated chitosan through naphthalimide moiety for enhanced gene transfection efficiency.  

PubMed

Development of efficient and safe gene carrier is the main hurdle for successful gene therapy till date. Poor water solubility and low transfection efficiency of chitosan are the main drawbacks to be efficient gene carrier for successful gene therapy. In this work, PAMAM conjugated chitosan was prepared through naphthalimide moiety by simple substitution reaction. The synthesis of the chitosan conjugates was confirmed by FTIR, (1)H NMR and XRD analyses. The conjugates showed enhanced DNA binding capability compared to that of unmodified chitosan. Moreover, the conjugates showed minimal cytotoxicity compared to that of polyethyleneimine (PEI, 25 kDa) and also showed good blood compatibility with negligible haemolysis. The transfection efficiency of the conjugate was significantly increased compared to that of unmodified chitosan and it also surpassed the transfection efficiency by PEI. Therefore, PAMAM conjugated chitosan can be used safely as alternate efficient gene delivery vector in gene therapy. PMID:23987374

Sarkar, Kishor; Kundu, P P

2013-10-15

268

Nasal delivery of insulin using bioadhesive chitosan gels.  

PubMed

Recently nasal delivery of insulin has gained considerable attention. Some limitations of this route include rapid mucociliary clearance of the drug from the site of deposition resulting in short time span available for absorption and low permeability of the nasal membrane for peptides. The objective of the present study was development of a chitosan bioadhesive gel for nasal delivery of insulin. A nasal perfusion test was used to study the toxicity of 4 absorption enhancers: saponin, sodium deoxycholate, ethylendiamine tetra-Acetic Acid (EDTA) and lecithin. The gels contained 4,000 Iu/dl insulin, 2 or 4% of low and medium molecular weight of chitosan, and lecithin or EDTA. Drug release was studied by a membraneless diffusion method and bioadhesion by a modified tensiometry test. The optimized gel was administered nasally in diabetic rats. The serum insulin levels were analyzed by an insulin enzyme immunoassay kit and serum glucose by glucose oxidase method kits. Formulations containing 2% of low molecular weight of chitosan with EDTA had higher release percentage and dissolution efficiency (DE)(2.5%), lower T(50%) (Time required to release 50% of the drug), mean dissolution time, and bioadhesion than gels containing 4% of medium molecular weight of chitosan with lecithin. Insulin was released by a zero-order kinetic from the gels. The gel of 2% medium molecular weight of chitosan with EDTA caused increase in insulin absorption and reduction the glucose level by as much as 46% of the intravenous route. Considering our in vitro and in vivo studies, the proposed gel formulation could be a useful preparation for controlled delivery of insulin through the nasal route. PMID:16401591

Varshosaz, Jaleh; Sadrai, Hassan; Heidari, Alireza

2006-01-01

269

Cytotoxicity of monodispersed chitosan nanoparticles against the Caco-2 cells  

SciTech Connect

Published toxicology data on chitosan nanoparticles (NP) often lack direct correlation to the in situ size and surface characteristics of the nanoparticles, and the repeated NP assaults as experienced in chronic use. The aim of this paper was to breach these gaps. Chitosan nanoparticles synthesized by spinning disc processing were characterised for size and zeta potential in HBSS and EMEM at pHs 6.0 and 7.4. Cytotoxicity against the Caco-2 cells was evaluated by measuring the changes in intracellular mitochondrial dehydrogenase activity, TEER and sodium fluorescein transport data and cell morphology. Cellular uptake of NP was observed under the confocal microscope. Contrary to established norms, the collective data suggest that the in vitro cytotoxicity of NP against the Caco-2 cells was less influenced by positive surface charges than by the particle size. Particle size was in turn determined by the pH of the medium in which the NP was dispersed, with the mean size ranging from 25 to 333 nm. At exposure concentration of 0.1%, NP of 25 ± 7 nm (zeta potential 5.3 ± 2.8 mV) was internalised by the Caco-2 cells, and the particles were observed to inflict extensive damage to the intracellular organelles. Concurrently, the transport of materials along the paracellular pathway was significantly facilitated. The Caco-2 cells were, however, capable of recovering from such assaults 5 days following NP removal, although a repeat NP exposure was observed to produce similar effects to the 1st exposure, with the cells exhibiting comparable resiliency to the 2nd assault. -- Highlights: ? Chitosan nanoparticles reduced mitochondrial dehydrogenase activity. ? Cellular uptake of chitosan nanoparticles was observed. ? Chitosan nanoparticles inflicted extensive damage to the cell morphology. ? The transport of materials along the paracellular pathway was facilitated.

Loh, Jing Wen [Laboratory for Drug Delivery, Pharmacy, Characterisation and Analysis, University of Western Australia (Australia)] [Laboratory for Drug Delivery, Pharmacy, Characterisation and Analysis, University of Western Australia (Australia); Saunders, Martin [Centre for Microscopy, Characterisation and Analysis, University of Western Australia (Australia)] [Centre for Microscopy, Characterisation and Analysis, University of Western Australia (Australia); Lim, Lee-Yong, E-mail: lee.lim@uwa.edu.au [Laboratory for Drug Delivery, Pharmacy, Characterisation and Analysis, University of Western Australia (Australia) [Laboratory for Drug Delivery, Pharmacy, Characterisation and Analysis, University of Western Australia (Australia); School of Biomedical, Biomolecular and Chemical Sciences, 35 Stirling Hwy, Crawley 6009 (Australia)

2012-08-01

270

Preparation, Characterization and Drug Release in Vitro of Galactosylated Chitosan-Graft-PEG Nanoparticles  

Microsoft Academic Search

Abstract-Galactose group was coupled with chitosan for liver specificity, and Poly(ethylene glycol) was selected to modify galactosylated chitosan (GC) for stability in water and enhanced cell permeability. The chemical structure of galactosylated chitosan-graft-PEG (GCP) was characterized by FT-IR and 1H-NMR techniques. Norcantharidin was chosen as model drug and encapsulated within GCP nanoparticles through ionic gelification. Transmission electron microscope (TEM) and

Xueqiong Zhang; Hua Zheng; Bo Lu; Fuliang Xiong

2010-01-01

271

In Vitro Release of Dexamethasone or bFGF from Chitosan\\/Hydroxyapatite Scaffolds  

Microsoft Academic Search

Chitosan scaffolds containing dexamethasone (Dex) or basic fibroblast growth factor (bFGF) were developed to create alternative drug-delivery systems for possible tissue-engineering applications such as periodontal bone regeneration. Chitosan solutions (2% and 3% (w\\/v) in acetic acid) were prepared from chitosan flakes with high deacetylation degree (>85%), then these solutions were freeze-dried at –80°C to obtain scaffolds with interconnected pore structures.

R. Seda T??l?; Abdullah C. Akman; Menem?e Gümü?derel?o?lu; Rahime M. Nohutçu

2009-01-01

272

Antimicrobial activity of chitosan against vibrios from freshwater prawn Macrobrachium rosenbergii larval rearing systems.  

PubMed

Chitosan is a biocompatible and biodegradable natural polymer with established antimicrobial properties against specific microorganisms. The present study demonstrates its antibacterial activity against 48 isolates of Vibrio species from prawn larval rearing systems. The antibacterial activity had a positive correlation with the concentration of chitosan. This work opens up avenues for using chitosan as a prophylactic biopolymer for protecting prawn larvae from vibriosis. PMID:16385825

Anas, A; Paul, S; Jayaprakash, N S; Philip, R; Bright Singh, I S

2005-11-01

273

Mechanical properties of chitosan\\/bamboo charcoal composite films made with normal and surface oxidized charcoal  

Microsoft Academic Search

Chitosan\\/bamboo charcoal composite films were prepared by blending chitosan with either virgin bamboo charcoal or bamboo charcoal modified by nitric acid oxidation to provide more hydrophilic regions on the bamboo charcoal surface. Investigation of the physical properties of these composite films revealed that the tensile strength and Young’s modulus of the chitosan films were enhanced in a dose-dependent manner by

Walaikorn Nitayaphat; Nantana Jiratumnukul; Sireerat Charuchinda; Siriwan Kittinaovarat

2009-01-01

274

Effect of chitosan on growth and plasma membrane properties of Rhizopus stolonifer (Ehrenb.:Fr.) Vuill  

Microsoft Academic Search

The effect of chitosan (0.5, 1.0 and 2.0mgml?1) on mycelium growth, potassium efflux, pH of the incubation medium, and activity of plasma membrane H+-ATPase of Rhizopus stolonifer was evaluated. The mycelium growth of R. stolonifer was reduced on media amended with chitosan at 1.0 and 2.0mgml?1. The highest antifungal index (65%) was obtained on media containing chitosan at 2.0mgml?1. Potassium

J. García-Rincón; J. Vega-Pérez; M. G. Guerra-Sánchez; A. N. Hernández-Lauzardo; A. Peña-Díaz; M. G. Velázquez-Del Valle

2010-01-01

275

Amperometric hydrogen peroxide biosensor with sol–gel\\/chitosan network-like film as immobilization matrix  

Microsoft Academic Search

A new type of sol–gel\\/organic hybrid composite material based on the cross-linking of natural polymer chitosan with (3-aoryloxypropyl) dimethoxymethylsilane was developed for the fabrication of an amperometric H2O2 biosensor. The composite film was used to immobilize horseradish peroxidase (HRP) on a gold disk electrode. The properties of sol–gel\\/chitosan and sol–gel\\/chitosan-HRP films have been carefully characterized by atomic force microscopy and

Gang Wang; Jing-Juan Xu; Hong-Yuan Chen; Zu-Hong Lu

2003-01-01

276

Effects of Spray Drying on Physicochemical Properties of Chitosan Acid Salts  

Microsoft Academic Search

The effects of spray-drying process and acidic solvent system on physicochemical properties of chitosan salts were investigated.\\u000a Chitosan used in spray dryings was obtained by deacetylation of chitin from lobster (Panulirus argus) origin. The chitosan acid salts were prepared in a laboratory-scale spray drier, and organic acetic acid, lactic acid, and\\u000a citric acid were used as solvents in the process.

Mirna Fernández Cervera; Jyrki Heinämäki; Orestes López; Sirkka Liisa Maunu; Tommi Virtanen; Timo Hatanpää; Osmo Antikainen; Antonio Nogueira; Jorge Fundora; Jouko Yliruusi

2011-01-01

277

Platelet adhesion and activation on an amphoteric chitosan derivative bearing sulfonate groups  

Microsoft Academic Search

To improve blood compatibility of chitosan, a linear cationic polymer of d-glucosamine, we have synthesized an amphoteric derivative containing sulfonate functional groups. Unlike chitosan which is soluble only in acidic pH (<5.0), the sulfonated derivative was soluble over a wide pH range. Elemental analysis of N-sulfofurfuryl chitosan showed 5.20% sulfur content and the degree of substitution analysis confirmed 23.4% sulfofurfuryl

Mansoor M Amiji

1998-01-01

278

Recent advances on chitosan-based micro- and nanoparticles in drug delivery  

Microsoft Academic Search

Considerable research efforts have been directed towards developing safe and efficient chitosan-based particulate drug delivery systems. The present review outlines the major new findings on the pharmaceutical applications of chitosan-based micro\\/nanoparticulate drug delivery systems published over the past decade. Methods of their preparation, drug loading, release characteristics, and applications are covered. Chemically modified chitosan or its derivatives used in drug

Sunil A. Agnihotri; Nadagouda N. Mallikarjuna; Tejraj M. Aminabhavi

2004-01-01

279

Modification of chitosan by using samarium for potential use in drug delivery system.  

PubMed

In the presence of hydroxyl and amine groups, chitosan is highly reactive; therefore, it could be used as a carrier in drug delivery. For this study, chitosan-Sm complexes with different concentrations of samarium from 2.5 to 25 wt.% have been successfully synthesized by the impregnation method. Chitosan combined with Sm3+ ions produced a drug carrier material with fluorescence properties; thus, it could also be used as an indicator of drug release with ibuprofen (IBU) as a model drug. We evaluated the spectroscopic and interaction properties of chitosan and Sm3+ ions, the interaction of chitosan-Sm matrices with IBU as a model drug, and the effect of Sm3+ ions addition on the chitosan ability to adsorb the drug. The result showed that the hypersensitive fluorescence intensity of chitosan-Sm (2.5 wt.%) is higher than the others, even though the adsorption efficiency of chitosan-Sm 2.5wt.% is lower (29.75%) than that of chitosan-Sm 25 wt.% (33.04%). Chitosan-Sm 25 wt.% showed the highest efficiency of adsorption of ibuprofen (33.04%). In the release process of ibuprofen from the chitosan-Sm-IBU matrix, the intensity of orange fluorescent properties in the hypersensitive peak of 4G5/2?6H7/2 transition at 590 nm was observed. Fluorescent intensity increased with the cumulative amount of IBU released; therefore, the release of IBU from the Sm-modified chitosan complex can be monitored by the changes in fluorescent intensity. PMID:24177873

Kusrini, Eny; Arbianti, Rita; Sofyan, Nofrijon; Abdullah, Mohd Aidil A; Andriani, Fika

2014-01-01

280

Chitosan Nanofibrous Scaffold Fabricated via Electrospinning: The Effect of Processing Parameters on the Nanofiber Morphology  

Microsoft Academic Search

Chitosan nanofibers were electrospun by using chitosan and triflouroacetic acid (TFA) solution as a solvent. Morphological characteristics of chitosan nanofibers fabricated by the electrospinning technique in different applied voltages (15–25 kV) and tip-to-collector distances (TCD) (5–15 cm) were examined using scanning electron microscopy (SEM). SEM images of electrospun nanofibers showed that morphology and diameter of the nanofibers were mainly affected by applied

T. Mazoochi; V. Jabbari

2011-01-01

281

Synthesis of Conjugated Chitosan and its Effect on Drug Permeation from Transdermal Patches  

PubMed Central

The aim of this study was to synthesis the conjugated chitosan by covalent attachment of thiol moieties to the cationic polymer, mediated by a carbodiimide to improve permeation properties of chitosan. Thioglycolic acid was covalently attached to chitosan by the formation of amide bonds between the primary amino groups of the polymer and the carboxylic acid groups of thioglycolic acid. Hence, these polymers are called as thiomers or thiolated polymers. Conjugation of chitosan was confirmed by Fourier transform-infrared and differential scanning calorimetric analysis. Matrix type transdermal patches of carvedilol were prepared using the different proportions of chitosan and chitosan-thioglycolic acid conjugates (2:0, 1.7:0.3, 1.4:0.6, 1:1, 0.6:1.4 and 0.3:1.7) by solvent casting technique. Prepared matrix type patches were evaluated for their physicochemical characterization followed by in vitro evaluation. Selected formulations were subjected for their ex vivo studies on Wistar albino rat skin and human cadaver skin using the modified Franz diffusion cell. As the proportion of conjugated chitosan increased, the transdermal patches showed increased drug permeation. The mechanism of drug release was found to be nonFickian profiles. The present study concludes that the transdermal patches of carvedilol using conjugated chitosan with different proportions of chitosan were successfully developed to provide improved drug permeation. The transdermal patches can be a good approach to improve drug bioavailability by bypassing the extensive hepatic first-pass metabolism of the drug. PMID:24019564

Satheeshababu, B. K.; Shivakumar, K. L.

2013-01-01

282

Porous chitosan scaffolds with surface micropatterning and inner porosity and their effects on Schwann cells.  

PubMed

Chitosan is found to promote the regeneration of peripheral nerve system in our previous studies, whereas the regeneration speed is not satisfied with clinical request. Micropatterning could promote cell orientation and growth, however, the effect of porous chitosan micropatterning on nerve regeneration is rarely reported. In this study, the porous chitosan micropatterning with surface ridge/groove and inner porosity structure was fabricated using a combination of micromodeling and lyophilization method. The morphology and stability of the prepared chitosan micropatterning were evaluated, the regulation of Schwann cells behavior by chitosan micropatterning was evaluated. The results showed that the chitosan micropatterning displayed stripe-like structure with a clear and complete edge. The micropatterning with 30/30 ?m was more stable than 20/20 ?m sample. Schwann cells on chitosan micropatterning showed orientation adhesion and began to grow along a certain direction after culture for 2 h, and displayed the minimal orientation angle and the largest length/width ratio on 30/30 ?m micropatterning after further culture for 3 d and 5 d, indicating the most obvious cell orientation. Moreover, the secretion of nerve growth factor (NGF) demonstrated that the micropatterned chitosan had no negative influence on the physiological function of Schwann cells. Thus, the results indicate that the porous chitosan micropatterning can regulate Schwann cell growth well, which may have potential application in nerve regeneration. The study provides an important basis for constructing porous nerve conduit with micropatterning structure in the inner wall. PMID:25002265

Li, Guicai; Zhao, Xueying; Zhao, Weixin; Zhang, Luzhong; Wang, Caiping; Jiang, Maorong; Gu, Xiaosong; Yang, Yumin

2014-10-01

283

A sulfuric-lactic acid process for efficient purification of fungal chitosan with intact molecular weight.  

PubMed

The most recent method of fungal chitosan purification, i.e., two steps of dilute sulfuric acid treatment, pretreatment of cell wall at room temperature for phosphate removal and extraction of chitosan from the phosphate free cell wall at high temperature, significantly reduces the chitosan molecular weight. This study was aimed at improvement of this method. In the pretreatment step, to choose the best conditions, cell wall of Rhizopus oryzae, containing 9% phosphate, 10% glucosamine, and 21% N-acetyl glucosamine, was treated with sulfuric, lactic, acetic, nitric, or hydrochloric acid, at room temperature. Sulfuric acid showed the best performance in phosphate removal (90%) and cell wall recovery (89%). To avoid depolymerisation of chitosan, hot sulfuric acid extraction was replaced with lactic acid treatment at room temperature, and a pure fungal chitosan was obtained (0.12 g/g cell wall). Similar pretreatment and extraction processes were conducted on pure shrimp chitosan and resulted in a chitosan recovery of higher than 87% while the reduction of chitosan viscosity was less than 15%. Therefore, the sulfuric-lactic acid method purified the fungal chitosan without significant molecular weight manipulation. PMID:24211428

Naghdi, Mitra; Zamani, Akram; Karimi, Keikhosro

2014-02-01

284

Green conversion of agroindustrial wastes into chitin and chitosan by Rhizopus arrhizus and Cunninghamella elegans strains.  

PubMed

This article sets out a method for producing chitin and chitosan by Cunninghamella elegans and Rhizopus arrhizus strains using a green metabolic conversion of agroindustrial wastes (corn steep liquor and molasses). The physicochemical characteristics of the biopolymers and antimicrobial activity are described. Chitin and chitosan were extracted by alkali-acid treatment, and characterized by infrared spectroscopy, viscosity and X-ray diffraction. The effectiveness of chitosan from C. elegans and R. arrhizus in inhibiting the growth of Listeria monocytogenes, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella enterica, Escherichia coli and Yersinia enterocolitica were evaluated by determining the minimum inhibitory concentrations (MIC) and the minimum bactericidal concentrations (MBC). The highest production of biomass (24.60 g/L), chitin (83.20 mg/g) and chitosan (49.31 mg/g) was obtained by R. arrhizus. Chitin and chitosan from both fungi showed a similar degree of deacetylation, respectively of 25% and 82%, crystallinity indices of 33.80% and 32.80% for chitin, and 20.30% and 17.80% for chitosan. Both chitin and chitosan presented similar viscosimetry of 3.79-3.40 cP and low molecular weight of 5.08×10³ and 4.68×10³ g/mol. They both showed identical MIC and MBC for all bacteria assayed. These results suggest that: agricultural wastes can be produced in an environmentally friendly way; chitin and chitosan can be produced economically; and that chitosan has antimicrobial potential against pathogenic bacteria. PMID:24853288

Berger, Lúcia Raquel Ramos; Stamford, Thayza Christina Montenegro; Stamford-Arnaud, Thatiana Montenegro; de Alcântara, Sergio Roberto Cabral; da Silva, Antonio Cardoso; da Silva, Adamares Marques; do Nascimento, Aline Elesbão; de Campos-Takaki, Galba Maria

2014-01-01

285

Adsorption of allura red dye by cross-linked chitosan from shrimp waste.  

PubMed

The present study was designed to evaluate the chitosan, which has been obtained by deacetylation of chitin, as a biosorbent. The chitin was isolated from fermented shrimp waste by an important local industrial food biopolymer. The aim of this work was the characterization of chitosan and preparation of cross-linked chitosan- tripolyphosphate (chitosan-TPP) beads for the removal of allura red food dye from aqueous solutions. Conditions of batch adsorption such as pH, time and adsorbent dose were examined. The effectiveness of cross-linked chitosan beads for dye removal was found to be higher for pH 2 (98%, percentage of dye removal) and tends to decrease at pHs of 3 to 11 (up to 49%). The values of percentage removal show that the adsorption capacity increases with time of contact and dosage of chitosan-TPP, but red dye adsorption is mainly influenced by pH level. The cross-linked chitosan-TPP beads can significantly adsorb allura red monoazo dye from aqueous solutions even at acidic pHs unlike raw chitosan beads that tend to dissolve in acidic solutions. Consequently, this modified chitosan has characteristics that allow minimization of environmental pollution and widening the valorization of shrimp waste. PMID:22277220

Sánchez-Duarte, Reyna G; Sánchez-Machado, Dalia I; López-Cervantes, Jaime; Correa-Murrieta, Ma A

2012-01-01

286

Histologic evaluation of chitosan as an accelerator of bone regeneration in microdrilled rat tibias  

PubMed Central

Background: Chitosan compounds have been shown to be suitable bone replacement materials. To evaluate the accelerating effects of chitosan on the bone regeneration process and assessing its histopathological adverse effects, we conducted this study on rat tibias. Materials and Methods: In a laboratory experimental study, micro-drilled bone defects were created in the upper tibia of each leg in 15 adult male rats. The defect in the right leg, filled by the chitosan powder, was compared with the untreated defect in the left leg in each rat at 1, 2, and 4 weeks after surgery. Bone repair and inflammation in each specimen was blindly graded by a pathologist. Reaction to the foreign body and the amount of the remaining chitosan were studied in chitosan-treated specimens at the three stages of the study. Results: Bone repair was significantly faster in the chitosan group, 1 week (P = 0.01) and 4 weeks (P = 0.038) after surgery, while the difference was not significant at the 2-week stage (P = 0.197) between chitosan and control groups. Chitosan-induced inflammation was not significant in any stage of the study. Reaction to the foreign body was seen in one case at 2 weeks and one case at 4 weeks postoperation. Conclusion: Chitosan significantly accelerated the bone regeneration process in rat tibias. Regarding its biocompatibility and osteoinductivity, it can be studied as a biomaterial in human bone healing. PMID:23559943

Ezoddini-Ardakani, Fatemeh; Navabazam, Alireza; Fatehi, Farhad; Danesh-Ardekani, Mohamad; Khadem, Somayyeh; Rouhi, Gholamreza

2012-01-01

287

Tyrosinase-containing chitosan gels: A combined catalyst and sorbent for selective phenol removal  

SciTech Connect

There are a series of examples in which phenols appear as contaminants in process streams and their selective removal is required for waste minimization. For the selective removal of a phenol from a mixture, the authors are exploiting the substrate specificity of the enzyme tyrosinase to convert phenols into reactive o-quinones which are then adsorbed onto the amine-containing polymer chitosan. To effectively package the enzyme and sorbent, tyrosinase was immobilized between two chitosan gel films. The entrapment of tyrosinase between the films led to little loss of activity during immobilization, while tyrosinase leakage during incubation was limited. The chitosan gels rapidly adsorb the tyrosinase-generated product(s) of phenol oxidation while the capacity of the gels is substantially greater than the capacity of chitosan flakes. The performance of tyrosinase-containing chitosan gels significantly depends on the ratio of tyrosinase-to-chitosan. High tyrosinase-to-chitosan ratios result in less efficient use of tyrosinase, presumably due to suicide inactivation. However, the efficiency of chitosan use increases with increased tyrosinase-to-chitosan ratios.

Sun, W.Q.; Payne, G.F. [Univ. of Maryland, Baltimore, MD (United States)] [Univ. of Maryland, Baltimore, MD (United States)

1996-07-05

288

Chitosan and oligochitosan enhance the resistance of peach fruit to brown rot.  

PubMed

The effects of chitosan and oligachitosan on resistance induction of peach fruit against brown rot caused by Monilinia fructicola were investigated. Both chitosan and oligochitosan showed significant effect on controlling this disease. Moreover, chitosan and oligochitosan delayed fruit softening and senescence. The two antifungal substances enhanced antioxidant and defense-related enzymes, such as catalase (CAT), peroxidase (POD), ?-1,3-glucanase (GLU) and chitinase (CHI), and they also stimulated the transcript expression of POD and GLU. These findings suggest that the effects of chitosan and oligochitosan on disease control and quality maintenance of peach fruit may be associated with their antioxidant property and the elicitation of defense responses in fruit. PMID:23544538

Ma, Zengxin; Yang, Lingyu; Yan, Haixia; Kennedy, John F; Meng, Xianghong

2013-04-15

289

Serum-free culture of rat proximal tubule cells with enhanced function on chitosan.  

PubMed

The proximal tubule performs a variety of important renal functions and is the major site for nutrient reabsorption. The purpose of this study is to culture rat renal proximal tubule cells (PTCs) on chitosan without serum to maintain a transcellular pathway to transport water and ions effectively without loss of highly differentiated cell function. The effect of chitosan, which is structurally similar to glycosaminoglycans, in the absence of serum on the primary cultured PTCs was compared that of collagen with or without serum. Two days after seeding, more tubule fragments and higher PTC viability were observed on chitosan than on collagen with or without serum. Proliferation marker Ki-67 immunostaining and phosphorylated extracellular-regulated kinase (ERK) expression results displayed similar proliferation capability of PTCs established on chitosan without serum and collagen with 2% fetal bovine serum after 4 days of incubation. When grown to confluence, PTCs formed a monolayer with well-organized tight junctions and formation of domes on chitosan without serum. Moreover, evaluation of the transepithelial electrical resistance showed that both chitosan and serum were involved in the modification of water and ion transport in confluent cells. By showing the direct suppression of PTC growth and dome formation treated with heparinase, we demonstrated that the interaction between cell surface heparin sulfate proteoglycan and chitosan played an important role in PTC proliferation and differentiation. A successful primary culture of PTCs has now been produced on chitosan in serum-free culture condition, which offers potential applications for chitosan in renal tissue engineering. PMID:23816651

Chang, Shao-Hsuan; Chiang, I-Ni; Chen, Yi-Hsin; Young, Tai-Horng

2013-11-01

290

In vivo application of chitosan to facilitate intestinal acyclovir absorption in rats.  

PubMed

The effect of chitosan on the intestinal absorption of acyclovir (ACV) was evaluated in rats, and factors influencing its facilitative effect on the ACV absorption were examined. When ACV solution containing 1% chitosan with an average molecular weight of 150 kDa was administered into the upper jejunum, a significant increase in the plasma ACV concentration was observed, with the peak ACV concentration being eight times greater than that observed with the chitosan-free solution. The chitosan-free ACV solution, whose viscosity was adjusted to remain unchanged with polyethylene glycol, did not cause an increase in the plasma concentration, and neither did the chitosan-free solutions substitutionally containing low molecular cationic compounds, triethanolamine and kanamycin. When chitosan was digested with chitosanase to shorten its polycationic polysaccharide structure, chitosan subjected to 150-min digestion retained its facilitative effect on ACV absorption, but that subjected to 420-min digestion no longer caused facilitation, in which its average molecular weight was reduced to around 10 kDa. It is therefore indicated that intestinal ACV absorption can be facilitated with chitosan, and that it is necessary for chitosan to have a certain length of polycationic polysaccharide structure to exert such facilitation. PMID:22535511

Masuda, Ayumi; Goto, Yuko; Kurosaki, Yuji; Aiba, Tetsuya

2012-07-01

291

TNF-? gene silencing using polymerized siRNA/thiolated glycol chitosan nanoparticles for rheumatoid arthritis.  

PubMed

Among various proinflammatory cytokines involved in the pathogenesis of rheumatoid arthritis (RA), tumor necrosis factor (TNF)-? plays a pivotal role in the release of other cytokines and induction of chronic inflammation. Even though siRNA has the therapeutic potential, they have a challenge to be delivered into the target cells because of their poor stability in physiological fluids. Herein, we design a nanocomplex of polymerized siRNA (poly-siRNA) targeting TNF-? with thiolated glycol chitosan (tGC) polymers for the treatment of RA. Poly-siRNA is prepared through self-polymerization of thiol groups at the 5' end of sense and antisense strand of siRNA and encapsulated into tGC polymers, resulting in poly-siRNA-tGC nanoparticles (psi-tGC-NPs) with an average diameter of 370?nm. In the macrophage culture system, psi-tGC-NPs exhibit rapid cellular uptake and excellent in vitro TNF-? gene silencing efficacy. Importantly, psi-tGC-NPs show the high accumulation at the arthritic joint sites in collagen-induced arthritis (CIA) mice. Treatment monitoring data obtained by the matrix metalloproteinase 3-specific nanoprobe and microcomputed tomography show that intravenous injection of psi-tGC-NPs significantly inhibits inflammation and bone erosion in CIA mice, comparable to methotrexate (5?mg/kg). Therefore, the availability of psi-tGC-NP therapy that target specific cytokines may herald new era in the treatment of RA. PMID:24145554

Lee, So Jin; Lee, Aeju; Hwang, Seung Rim; Park, Jong-Sung; Jang, Jiyeon; Huh, Myung Sook; Jo, Dong-Gyu; Yoon, Soo-Young; Byun, Youngro; Kim, Sun Hwa; Kwon, Ick Chan; Youn, Inchan; Kim, Kwangmeyung

2014-02-01

292

Inhalable microspheres embedding chitosan-coated PLGA nanoparticles for 2-methoxyestradiol.  

PubMed

Developing a highly effective and lung-targeted local drug delivery carrier with low irritancy may be critical for improving treatment of lung cancer. Using soluble excipients as microspheres (MS) matrix, respirable MS embedding chitosan-coated poly(d,l-lactide-co-glycolide) nanoparticles (CNP-MS) for 2-methoxyestradiol (2-ME) were designed, which could avoid macrophage phagocytosis to achieve the targeted delivery of these drugs. 2-ME CNP-MS were prepared by spray-drying and characterized by morphology, redispersability, fine particle fraction (FPF) and drug release. Cytotoxicity, and lung deposition and histological examination were investigated. Results showed that 2-ME CNP-MS were spherical with a rough surfaces, exhibiting good redispersability, a high respirable fraction and sustained release characteristics. CNP-MS markedly enhanced the cytotoxicity of 2-ME by approximately 8.8-fold and 3.65-fold on SPC-A1 cells compared to solution and NP, respectively. After pulmonary administration, 2-ME CNP were distributed in rat lungs and for 10?mg of 2-ME CNP-MS, haematoxylin and eosin staining showed no obvious difference compared to the untreated control group. Therefore, CNP-MS revealed suitable features for local lung delivery and significantly enhanced cytotoxicity of 2-ME without obvious inflammation in lungs of rats, suggesting that 2-ME CNP-MS have great potential as an inhalation agent for targeted, highly effective and safe treatment of lung cancer. PMID:24417740

Guo, XinHong; Zhang, XinXin; Ye, Ling; Zhang, Ying; Ding, Rui; Hao, YongWei; Zhao, YaLin; Zhang, ZhenZhong; Zhang, Yun

2014-06-01

293

Biomimetic apatite-coated alginate/chitosan microparticles as osteogenic protein carriers  

PubMed Central

Bone morphogenetic proteins (BMPs) are currently approved for spinal fusion, tibial fracture repair, and maxillofacial bone regeneration. However, BMP pleiotropism, paradoxical activities on precursor cells, and unexpected side effects at local and ectopic sites may limit their usage. Thus, the need remains for alternative osteoinductive factors that provide more bone-specific activities with fewer adverse effects. Nell-1 [Nel-like molecule-1; Nel (a protein highly expressed in neural tissue encoding epidermal growth factor like domain)] is a novel osteogenic protein believed to specifically target cells committed to the osteogenic lineage. The objective of this project is to incorporate Nell-1 into a moldable putty carrier that can adapt to bony defects and deliver Nell-1 to the local microenvironment. We show here that moldability can be achieved by mixing hyaluronan hydrogel with two types of particles: demineralized bone powder for osteoconductivity, and biomimetic apatite-coated alginate/chitosan microparticles for controlled Nell-1 delivery. Besides enhancing overall osteoconductivity of the carrier, the biomimetic apatite coating also provides a more sustained release (? 15% cumulative release over 30 days) and greatly reduces the initial burst release that is observed with non-coated alginate/chitosan microparticles (? 40% release after 1 day). The efficacy of Nell-1 delivery from these carriers was evaluated in a rat spinal fusion model against Nell-free carriers as controls. 4 weeks post-implantation, Nell-1 enhanced spinal fusion rates as measured by manual palpation, radiographs, high resolution micro-computerized tomography (?CT), and histology. This moldable putty carrier system appears to be a suitable carrier for promoting osteogenesis, and will be further evaluated in larger animal models over longer periods to follow the remodeling of the regenerated bone. PMID:19674782

Lee, Min; Li, Weiming; Siu, Ronald K.; Whang, Julie; Zhang, Xinli; Soo, Chia; Ting, Kang; Wu, Benjamin M.

2009-01-01

294

A model for the hypolipidemic effect of chitosan : in vitro binding of bile acids and mixed micelles  

E-print Network

in triglycerides, a factor also associated with increased CHD risk (32). At present, one natural non-digestible polycationic fiber is known; it is called chitosan. Resulting from the alkaline 14 hydrolysis of chitin, chitosan is an indefinite polymer of gluco... in triglycerides, a factor also associated with increased CHD risk (32). At present, one natural non-digestible polycationic fiber is known; it is called chitosan. Resulting from the alkaline 14 hydrolysis of chitin, chitosan is an indefinite polymer of gluco...

Nauss, Jeffrey Lynn

2012-06-07

295

Non-isothermal kinetics of thermal degradation of chitosan  

PubMed Central

Background Chitosan is the second most abundant nitrogen containing biopolymer in nature, obtained from the shells of crustaceans, particularly crabs, shrimp and lobsters, which are waste products of seafood processing industries. It has great potential application in the areas of biotechnology, biomedicine, food industries, and cosmetics. Chitosan is also capable of adsorbing a number of metal ions as its amino groups can serve as chelation sites. Grafted functional groups such as hydroxyl, carboxyl, sulfate, phosphate, and amino groups on the chitosan have been reported to be responsible for metal binding and sorption of dyes and pigments. The knowledge of their thermal stability and pyrolysis may help to better understand and plan their industrial processing. Results Thermogravimetric studies of chitosan in air atmosphere were carried out at six rates of linear increasing of the temperature. The kinetics and mechanism of the thermal decomposition reaction were evaluated from the TG data using recommended from ICTAC kinetics committee iso-conversional calculation procedure of Kissinger-Akahira-Sunose, as well as 27 mechanism functions. The comparison of the obtained results showed that they strongly depend on the selection of proper mechanism function for the process. Therefore, it is very important to determine the most probable mechanism function. In this respect the iso-conversional calculation procedure turned out to be the most appropriate. Conclusion Chitosan have excellent properties such as hydrophilicity, biocompatibility, biodegradability, antibacterial, non-toxicity, adsorption application. The thermal degradation of chitosan occurs in two stages. The most probable mechanism function for both stages is determined and it was best described by kinetic equations of n-th order (Fn mechanism). For the first stage, it was established that n is equal to 3.0 and for the second stage – to 1.0 respectively. The values of the apparent activation energy E, pre-exponential factor A in Arrhenius equation, as well as the changes of entropy ?S?, enthalpy ?H? and free Gibbs energy ?G? for the formation of the activated complex from the reagent are calculated. PMID:22857524

2012-01-01

296

Antifungal effects of chitosan with different molecular weights on in vitro development of Rhizopus stolonifer (Ehrenb.:Fr.) Vuill  

Microsoft Academic Search

Determination of the molecular weight of three types of chitosan was carried out by HPSEC-RI. The effect of low, medium and high molecular weight chitosan was evaluated on development of three isolates of Rhizopus stolonifer. Image analysis and electronic microscopy observations were done in spores of this fungus. Germination of R. stolonifer in potato dextrose broth with chitosan was also

A. N. Hernández-Lauzardo; S. Bautista-Baños; M. G. Velázquez-del Valle; M. G. Méndez-Montealvo; M. M. Sánchez-Rivera; L. A. Bello-Pérez

2008-01-01

297

Development and in vitro evaluation of chitosan-based transdermal drug delivery systems for the controlled delivery of propranolol hydrochloride  

Microsoft Academic Search

Membrane permeation-controlled transdermal drug delivery systems were prepared using the natural polymer, chitosan. An adhesive sealing technique was used to construct the devices. Propranolol hydrochloride was selected as the model drug for the present study. Chitosan membranes with different permeability to propranolol hydrochloride obtained by controlled cross-linking with glutaraldehyde were used to regulate the drug release in the devices. Chitosan

D. Thacharodi; K. Panduranga Rao

1995-01-01

298

Development and characterization of novel organic coatings based on biopolymer chitosan  

NASA Astrophysics Data System (ADS)

Chitosan, a derivative of naturally abundant biopolymer chitin, was used as the basis for corrosion resistant coating. Chitosan suffers from two inherent weaknesses as a coating material, namely its high hydrophilicity and its poor adhesive strength with Al 2024 T3 alloy. In the present study, the chitosan structure was modified using epoxy functional silane and vanadate. Two epoxy functional silanes (3-Glycidoxypropyl)-trimethoxysilane (GPTS) and (2-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane (ECET) were tested. The performance of different coatings was tested using electrochemical impedance spectroscopy, adhesion testing and salt spray testing. Addition of GPTS resulted in improvement in corrosion resistance and adhesive strength. Chitosan-GPTS-vanadate coatings prepared using chitosan-GPTS solution at viscosity 0.96 pa-s and post treated in NaVO3 solution at pH 6-8 demonstrated the highest corrosion resistance. The best salt spray performance was observed in case of chitosan-GPTS-vanadate coatings, which lasted 450 hours in salt spray chamber. Detailed fundamental characterization was carried out related to the structure, chemistry and properties of chitosan-based coatings using optical spectroscopy. FTIR spectra of chitosan gel showed adsorption of vanadate at protonated amine sites of chitosan. Chitosan showed a maximum in the vanadate adsorption capacity when treated in NaVO3 solution at pH 3-5. GPTS reacted with amine functional group of chitosan and, at the same time, formed a hydrophobic siloxane network with the Al alloy substrate. Formation of a siloxane network with the Al substrate provided the observed increase in corrosion and adhesive strength of the coatings. UV/Visible spectroscopy measurements showed release of vanadate by chitosan increases with increasing solution pH, increasing chloride concentration and polarizing the sample cathodically. Structured experiments have been used to show that vanadate is reversibly bound to chitosan. Adsorption and release have been found to depend strongly on the pH of the aqueous solution contacting the chitosan coating. When the solution pH is readjusted to a lower value, chitosan can re-adsorb released vanadate. Further, a direct electrochemically triggered release of inhibitor was demonstrated by cathodically polarizing the coated sample. Release of vanadate under different conditions demonstrated the on demand inhibitor release capability of the coatings. This capability of coating is useful to provide a self-healing effect.

Kumar, Girdhari

299

Chitosan as a potential osteogenic factor compared with dexamethasone in cultured macaque dental pulp stromal cells.  

PubMed

Chitosan, a natural biopolymer derived from chitin, is considered a promising scaffold material for bone tissue engineering. The ability of chitosan to promote the osteogenic differentiation of dental pulp stromal/stem cells (DPSCs) is unknown. We have evaluated the potential of chitosan to induce the osteogenic differentiation of macaque DPSCs in comparison with that of dexamethasone. DPSCs were cultured in mineralizing medium supplemented with 5 or 10 ?g/ml chitosan or with 1 or 10 nM dexamethasone. The metabolic activity of DPSCs was measured by MTT assay. Their osteogenic differentiation was determined by the number of transcripts of RUNX2, alkaline phosphatase (ALP), and COL1A1 by using real-time polymerase chain reaction, by alizarin red staining for mineral deposition, and by the ALP activity released into the medium for their ability to support biomineralizaton. Addition of chitosan to the mineralizing medium significantly increased DPSCs metabolism after 7 and 14 days of culture (P???0.0001). Chitosan at 5 ?g/ml also significantly enhanced RUNX2 and ALP mRNA but not COL1A1 mRNA; chitosan tended to increase the release of ALP hydrolytic enzyme activity into the medium during the first week. Dexamethasone upregulated the osteogenic markers tested. Mineral deposition was similar in the chitosan and dexamethasone groups and was not statistically different from that of the mineralizing control group. Thus, the potential of chitosan to stimulate DPSCs proliferation and early osteogenic differentiation is comparable with that of dexamethasone, but mineralization remains unaffected by chitosan treatment. In addition to its role as a three-dimensional scaffold for osteogenic cells in vivo, chitosan might also stimulate DPSCs proliferation and early osteogenic differentiation in vitro. PMID:24992928

Amir, Lisa R; Suniarti, Dewi F; Utami, Sri; Abbas, Basril

2014-11-01

300

A long acting biodegradable controlled delivery of chitosan microspheres loaded with tetanus toxoide as model antigen.  

PubMed

The chitosan microspheres formulated by emulsion cross-linking method were found to be smooth and spherical without aggregation. The particle size range was between 1 and 90?m. The particle sizes were found to be influenced by the concentration of the chitosan gel. Tetanus toxoide (TT) vaccine was loaded by passive adsorption from an aqueous solution into the preformed chitosan microspheres cross-linked with glutaraldehyde. The loaded TT on to microspheres was estimated by ELISA method. The loading capacity was found to be 40% with microspheres prepared with 1% chitosan gel, 43% for 2% and 46% for the mixed batch of microspheres prepared from 1% and 2% chitosan gel. The loading efficiency was found to decrease with increase in the concentration of chitosan gel. The in vitro release of the antigenic TT into the phosphate buffer at 37°C from different batch of microspheres was studied and release had a remarkable dependence on the size of micropsheres. The percentage release of TT from chitosan microspheres prepared from 1% chitosan gel was 2.7% in 120days and that from 2% chitosan gel was only 2%. The mixed batch of microspheres could release 2.3% in 120days. The antigen integrity was investigated by SDS-PAGE with brilliant blue staining. The SDS-PAGE analysis confirmed that the antigen integrity was not affected by passive adsorption of protein antigen to preformed chitosan microspheres. The study revealed that the cross-linked chitosan microspheres would be an interesting system for long-term delivery of macromolecules drugs. PMID:24051124

Varma, Sujith; Sadasivan, C

2014-03-01

301

Benzaldehyde dehydrogenase from chitosan-treated Sorbus aucuparia cell cultures.  

PubMed

Cell cultures of Sorbus aucuparia respond to the addition of chitosan with the accumulation of the biphenyl phytoalexin aucuparin. The carbon skeleton of this inducible defense compound is formed by biphenyl synthase (BIS) from benzoyl-CoA and three molecules of malonyl-CoA. The formation of benzoyl-CoA proceeds via benzaldehyde as an intermediate. Benzaldehyde dehydrogenase (BD), which converts benzaldehyde into benzoic acid, was detected in cell-free extracts from S. aucuparia cell cultures. BD and BIS were induced by chitosan treatment. The preferred substrate for BD was benzaldehyde (K(m)=49 microM). Cinnamaldehyde and various hydroxybenzaldehydes were relatively poor substrates. BD activity was strictly dependent on the presence of NAD(+) as a cofactor (K(m)=67 microM). PMID:19409654

Gaid, Mariam M; Sircar, Debabrata; Beuerle, Till; Mitra, Adinpunya; Beerhues, Ludger

2009-09-01

302

Nanosilica-Chitosan Composite Coating on Cotton Fabrics  

NASA Astrophysics Data System (ADS)

Nanosilica-chitosan composite coating on cotton fabrics has been prepared by sol-gel method. The sol-gel procedure allows coating of material on nanometer scale, which several commonly used coating procedure cannot achieve. In addition, sol-gel coating technique can be applied to system without disruption of their structure functionaly. The coating were produced via hidrolysis and condensation of TEOS and GPTMS and then mixed with chitosan. The composite coating on cotton fabrics were characterized with X-Ray Diffraction and Scanning Electron microscopy (SEM) method. The result showed that the coating not changed or disrupted the cotton stucture. The coating result in a clear transparent thin layer on cotton surface. The nanocomposite coating has new applications in daily used materials, especially those with low heat resistance, such as textiles and plastics, and as an environmentally friendly water-repellent substitute for fluorine compounds.

Maharani, Dina Kartika; Kartini, Indriana; Aprilita, Nurul Hidayat

2010-10-01

303

Preparation and characterization of nano-hydroxyapatite within chitosan matrix.  

PubMed

Nano-composites that show some features of natural bone both in composition and in microstructure have been prepared by in situ precipitation method. Apatite phase has been prepared from cost-effective precursors (calcite and urea phosphate) within chitosan (CS) matrix dissolved in aqueous acetic acid solution. The compositional and morphological properties of composites were studied by means of Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). Depending on the reaction conditions (temperature, reaction time, glucose addition and pH control) in addition to hydroxyapatite (HA) as a major phase, octacalcium hydrogen phosphate pentahydrate (OCP) and dicalcium phosphate anhydrate (DCPD) were formed as shown by XRD and FTIR. Crystallite lengths of precipitated HA estimated by Scherrer's equation were between 20 and 30 nm. A fibrous morphology (~400 nm) of HA observed by TEM indicates that HA nucleates on chitosan chains. PMID:24094157

Rogina, A; Ivankovi?, M; Ivankovi?, H

2013-12-01

304

Enhanced arsenic removal using mixed metal oxide impregnated chitosan beads.  

PubMed

Mixed metal oxide impregnated chitosan beads (MICB) containing nanocrystalline Al?O? and nanocrystalline TiO? were successfully developed. This adsorbent exploits the high capacity of Al?O? for arsenate and the photocatalytic activity of TiO? to oxidize arsenite to arsenate, resulting in a removal capacity higher than that of either metal oxide alone. The composition of the beads was optimized for maximum arsenite removal in the presence of UV light. The mechanism of removal was investigated and a mode of action was proposed wherein TiO? oxidizes arsenite to arsenate which is then removed from solution by Al?O?. Pseudo-second order kinetics were used to validate the proposed mechanism. MICB is a more efficient and effective adsorbent for arsenic than TiO?-impregnated chitosan beads (TICB), previously reported on, yet maintains a desirable life cycle, free of complex synthesis processes, toxic materials, and energy inputs. PMID:22743162

Yamani, Jamila S; Miller, Sarah M; Spaulding, Matthew L; Zimmerman, Julie B

2012-09-15

305

Chitosan coupling makes microbial biofilms susceptible to antibiotics.  

PubMed

Microbial biofilms, prevalent in nature and inherently resistant to both antimicrobial agents and host defenses, can cause serious problems in the chemical, medical and pharmaceutical industries. Herein we demonstrated that conjugation of an aminoglycoside antibiotic (streptomycin) to chitosan could efficiently damage established biofilms and inhibit biofilm formation. This method was suitable to eradiate biofilms formed by Gram-positive organisms, and it appeared that antibiotic contents, molecular size and positive charges of the conjugate were the key to retain this anti-biofilm activity. Mechanistic insight demonstrated chitosan conjugation rendered streptomycin more accessible into biofilms, thereby available to interact with biofilm bacteria. Thus, this work represent an innovative strategy that antibiotic covalently linked to carbohydrate carriers can overcome antibiotic resistance of microbial biofilms, and might provide a comprehensive solution to combat biofilms in industrial and medical settings. PMID:24284335

Zhang, Amin; Mu, Haibo; Zhang, Wuxia; Cui, Guoting; Zhu, Jie; Duan, Jinyou

2013-01-01

306

Chitosan/alginate complexes for vaginal delivery of chlorhexidine digluconate.  

PubMed

Chitosan/alginate complexes were prepared at different polycation/polyanion molar ratios and freeze-dried vaginal inserts were obtained for chlorhexidine digluconate local delivery in genital infections. Complex yield, FT-IR spectra, and TGA thermograms were studied to confirm the interaction between the two polyions. The influence of different complexes on physical handling, morphology, and drug distribution in the samples were evaluated by friability test, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS), respectively. In vitro water-uptake, mucoadhesion and release tests were performed as well as microbiological tests toward pathogenic vaginal microorganisms. The results showed that the selection of suitable chitosan/alginate molar ratio and drug loading allowed modulate insert ability to hydrate, adhere to the mucosa, and release chlorhexidine digluconate. The insert containing an excess of alginate was found to be the best performing formulation and showed good antimicrobial activity toward the pathogens Candida albicans and Escherichia coli. PMID:23121960

Abruzzo, A; Bigucci, F; Cerchiara, T; Saladini, B; Gallucci, M C; Cruciani, F; Vitali, B; Luppi, B

2013-01-16

307

In vitro antibakteriální aktivita obvazu Chitoskin®, obsahujícího chitosan  

Microsoft Academic Search

Summary: Using three bacterial strains the antibacterial activity of Chitoskin®, a chitosan-containing wound-dressing, was investigated by determining the viable bacterial cell count in liquid cultures in the absence and presence of Chitoskin®. Results were compared to those obtained for cellulose and silver-laminated cellulose. While the pure cellulose wound-dressing had no impact on the bacterial growth, Chitoskin® and, to an even

Tatjana Claussenová

308

Electrochemistry and electrocatalysis with heme proteins in chitosan biopolymer films  

Microsoft Academic Search

Protein–chitosan (CS) films were made by casting a solution of proteins and CS on pyrolytic graphite electrodes. Myoglobin (Mb), hemoglobin (Hb), and horseradish peroxidase (HRP) incorporated in CS films gave a pair of stable, well-defined, and quasi-reversible cyclic voltammetric peaks at about ?0.33V vs saturated calomel electrode in pH 7 buffers, respectively, while catalase (Ct) in CS films showed a

He Huang; Naifei Hu; Yonghuai Zeng; Gu Zhou

2002-01-01

309

Modified-Chitosan/siRNA Nanoparticles Downregulate Cellular CDX2 Expression and Cross the Gastric Mucus Barrier  

PubMed Central

Development of effective non-viral vectors is of crucial importance in the implementation of RNA interference in clinical routine. The localized delivery of siRNAs to the gastrointestinal mucosa is highly desired but faces specific problems such as the stability in gastric acidity conditions and the presence of the mucus barrier. CDX2 is a transcription factor critical for intestinal differentiation being involved in the initiation and maintenance of gastrointestinal diseases. Specifically, it is the trigger of gastric intestinal metaplasia which is a precursor lesion of gastric cancer. Its expression is also altered in colorectal cancer, where it may constitute a lineage-survival oncogene. Our main objective was to develop a nanoparticle-delivery system of siRNA targeting CDX2 using modified chitosan as a vector. CDX2 expression was assessed in gastric carcinoma cell lines and nanoparticles behaviour in gastrointestinal mucus was tested in mouse explants. We show that imidazole-modified chitosan and trimethylchitosan/siRNA nanoparticles are able to downregulate CDX2 expression and overpass the gastric mucus layer but not colonic mucus. This system might constitute a potential therapeutic approach to treat CDX2-dependent gastric lesions. PMID:24925340

Sadio, Ana; Gustafsson, Jenny K.; Pereira, Bruno; Gomes, Carla Pereira; Hansson, Gunnar C.; David, Leonor; Pego, Ana Paula; Almeida, Raquel

2014-01-01

310

Biocompatibility of Chitosan Carriers with Application in Drug Delivery  

PubMed Central

Chitosan is one of the most used polysaccharides in the design of drug delivery strategies for administration of either biomacromolecules or low molecular weight drugs. For these purposes, it is frequently used as matrix forming material in both nano and micron-sized particles. In addition to its interesting physicochemical and biopharmaceutical properties, which include high mucoadhesion and a great capacity to produce drug delivery systems, ensuring the biocompatibility of the drug delivery vehicles is a highly relevant issue. Nevertheless, this subject is not addressed as frequently as desired and even though the application of chitosan carriers has been widely explored, the demonstration of systems biocompatibility is still in its infancy. In this review, addressing the biocompatibility of chitosan carriers with application in drug delivery is discussed and the methods used in vitro and in vivo, exploring the effect of different variables, are described. We further provide a discussion on the pros and cons of used methodologies, as well as on the difficulties arising from the absence of standardization of procedures. PMID:24955636

Rodrigues, Susana; Dionisio, Marita; Remunan Lopez, Carmen; Grenha, Ana

2012-01-01

311

Multilayers of cellulose derivatives and chitosan on nanofibrillated cellulose.  

PubMed

The aim of this work was to study the effect of solution conditions and polysaccharide structure on their Layer-by-Layer (LbL) deposition on nanofibrillated cellulose (NFC). Multilayer build-up of cellulose derivatives and chitosan on NFC model surfaces was studied using Quartz Crystal Microbalance with Dissipation (QCM-D) and Colloidal Probe Microscopy (CPM). The type of cationic polysaccharide was found to significantly affect the multilayer build-up and surface interactions. Cationic cellulose derivative quaternized hydroxyethyl cellulose ethoxylate (HECE) formed highly water-swollen layers with carboxymethyl cellulose (CMC), and the build-up was markedly influenced by both the ionic strength and pH. The ionic strength did not significantly influence the multilayer build-up of chitosan-CMC system, and adsorbed chitosan layers decreased the viscoelasticity of the system. Based on the results, it was also confirmed that electrostatic interaction is not the only driving force in case of the build-up of polysaccharide multilayers on nanofibrillated cellulose. PMID:24751244

Junka, Karoliina; Sundman, Ola; Salmi, Jani; Osterberg, Monika; Laine, Janne

2014-08-01

312

Preparation of Chitosan Nanoparticles: A Study of Influencing Factors  

NASA Astrophysics Data System (ADS)

Chitosan (CS), a cationic polysaccharide, offers great advantages for ionic interactions with negatively charged species such as sodium tripolyphosphate (STPP) leading to the formation of biocompatible crosslinked chitosan nanoparticles In the present work, an attempt has been made to systematically study the following factors influencing the ionotropic gelation of chitosan with STPP to produce CS nanoparticles: effect of pH of solution, CS concentration, STPP concentration and CS/STPP ratio. The results show that with the increase in CS concentration, the yield of the nanoparticle decreases whereas size increases. The mean size of the prepared nanoparticles varied between 120 to 720 nm and zeta potential between +14 mV to +53 mV. Nanoparticle size and yield was found to be strongly dependent on solution pH. Nanoparticle size decreased with increase in solution pH from 4 to 5 and yield was found to be maximum at pH = 5. With increase in STPP concentration, the size and yield of the nanoparticle increased. The potential of CS nanoparticles to trap amoxicillin trihydrate, taken as the model drug, was also studied. The maximum drug loading capacity was found to be 35% at a solution pH = 5 for 0.2% CS and 0.086% STPP.

Thakur, Anupama; Taranjit

2011-12-01

313

Bioavailability enhancement of verapamil HCl via intranasal chitosan microspheres.  

PubMed

Chitosan microspheres are potential drug carriers for maximizing nasal residence time, circumventing rapid mucociliary clearance and enhancing nasal absorption. The aim of the present study was to develop and characterize chitosan mucoadhesive microspheres of verapamil hydrochloride (VRP) for intranasal delivery as an alternative to oral VRP which suffers low bioavailability (20%) due to extensive first pass effect. The microspheres were produced using a spray-drying and precipitation techniques and characterized for morphology (scanning electron microscopy), particle size (laser diffraction method), drug entrapment efficiency, thermal behavior (differential scanning calorimetry) and crystallinity (X-ray diffractometric studies) as well as in vitro drug release. Bioavailability of nasal VRP microspheres was studied in rabbits and the results were compared to those obtained after nasal, oral and intravenous administration of VRP solution. Results demonstrated that the microspheres were spherical with size 21-53 ?m suitable for nasal deposition. The spray-drying technique was superior over precipitation technique in providing higher VRP entrapment efficiency and smaller burst release followed by a more sustained one over 6h. The bioavailability study demonstrated that the nasal microspheres exhibited a significantly higher bioavailability (58.6%) than nasal solution of VRP (47.8%) and oral VRP solution (13%). In conclusion, the chitosan-based nasal VRP microspheres are promising for enhancing VRP bioavailability by increasing the nasal residence time and avoiding the first-pass metabolism of the drug substance. PMID:23999035

Abdel Mouez, Mamdouh; Zaki, Noha M; Mansour, Samar; Geneidi, Ahmed S

2014-01-23

314

Thermosensitive macroporous cryogels functionalized with bioactive chitosan/bemiparin nanoparticles.  

PubMed

Thermosensitive macroporous scaffolds of poly(N-isopropylacrylamide) (polyNIPA) loaded with chitosan/bemiparin nanoparticles are prepared by the free radical polymerization in cryogenic conditions. Chitosan/bemiparin nanoparticles of 102?±?6.5?nm diameter are prepared by complex coacervation and loaded into polyNIPA cryogels. SEM image reveal the highly porous structure of cryogels and the integration of nanoparticles into the macroporous system. Volume phase transition temperature (VPT) and total freezing water content of cryogels are established by differential scanning calorimetry, and their porosity is determined by image-NMR. Swelling of cryogels (above and below the VPT) is highly dependent on nanoparticles concentration. In vitro release profile of bemiparin from cryogel is highly modulated by the presence of chitosan. Bemiparin released from nanoparticles preserves its biological activity, as shown by the BaF32 cell proliferation assay. Cryogels are not cytotoxic for the human fibroblast cells and present excellent properties for application on tissue engineering and controlled release of heparin. PMID:23956200

Peniche, Hazel; Reyes-Ortega, Felisa; Aguilar, María R; Rodríguez, Gema; Abradelo, Cristina; García-Fernández, Luis; Peniche, Carlos; San Román, Julio

2013-11-01

315

Preparation and evaluation of chitosan microspheres containing nicorandil  

PubMed Central

Objectives: The objective of present study was to develop chitosan-based sustained release nicorandil microspheres to reduce the dosing frequency. Materials and Methods: The nicorandil-loaded chitosan microspheres were formulated by emulsion crosslinking method. A 32 factorial design was employed to study the influence of drug: Polymer ratio and volume of glutaraldehyde (GA) on percentage entrapment efficiency, particle size, and % drug release at 8 h. Results: The entrapment efficiency was found to be 41.67 ± 1.43-77.33 ± 1.97% and particle size range 65.67 ± 2.08-146.67 ± 2.18 ?m. The batch CH5 showed 79.11 ± 2.23 and 96.21 ± 2.41% drug release at 8 and 12 h, respectively. Conclusions: Drug: Polymer ratio and volume of GA had significant effect on % entrapment efficiency, particle size, and % drug release. From the scanning electron microscopy (SEM) study observed that microspheres were spherical and fairly smooth surface. Fickian diffusion was the mode of drug release from nicorandil-loaded chitosan microspheres formulations. PMID:24678460

Patel, Keyur S; Patel, Mandev B

2014-01-01

316

Chitosan modified ordered mesoporous silica as micro-column packing materials for on-line flow injection-inductively coupled plasma optical emission spectrometry determination of trace heavy metals in environmental water samples  

Microsoft Academic Search

A novel adsorbent of chitosan chemically modified ordered mesoporous silica was synthesized and employed as a solid phase extraction (SPE) material for flow injection (FI) micro-column preconcentration on-line coupled with inductively coupled plasma optical emission spectrometry (ICP-OES) determination of trace heavy metals V, Cu, Pb, Cd and Hg in environmental water samples. The factors affecting separation and preconcentration of target

Dahui Chen; Bin Hu; Chaozhang Huang

2009-01-01

317

Antifungal Activity of Chitosan Nanoparticles and Correlation with Their Physical Properties  

PubMed Central

The need of natural antimicrobials is paramount to avoid harmful synthetic chemicals. The study aimed to determine the antifungal activity of natural compound chitosan and its nanoparticles forms against Candida albicans, Fusarium solani and Aspergillus niger. Chitosan nanoparticles were prepared from low (LMW), high molecular weight (HMW) chitosan and its derivative, trimethyl chitosan (TMC). Particle size was increased when chitosan/TMC concentration was increased from 1 to 3 mg/mL. Their zeta potential ranged from +22 to +55?mV. Chitosan nanoparticles prepared from different concentrations of LMW and HMW were also found to serve a better inhibitory activity against C. albicans (MICLMW = 0.25–0.86?mg/mL and MICHMW = 0.6–1.0?mg/mL) and F. solani (MICLMW = 0.86–1.2?mg/mL and MICHMW = 0.5–1.2?mg/mL) compared to the solution form (MIC = 3?mg/mL for both MWs and species). This inhibitory effect was also influenced by particle size and zeta potential of chitosan nanoparticles. Besides, Aspergillus niger was found to be resistant to chitosan nanoparticles except for nanoparticles prepared from higher concentrations of HMW. Antifungal activity of nanoparticles prepared from TMC was negligible. The parent compound therefore could be formulated and applied as a natural antifungal agent into nanoparticles form to enhance its antifungal activity. PMID:22829829

Ing, Ling Yien; Zin, Noraziah Mohamad; Sarwar, Atif; Katas, Haliza

2012-01-01

318

Biomaterials 27 (2006) 48154824 High efficiency gene transfer using chitosan/DNA nanoparticles with  

E-print Network

produced 64 formulations of chitosan/pDNA complexes (16 chitosans, 2 amine-to- phosphate (N:P) ratios of 5 efficiency. To improve transfection efficiency, recent studies have examined the use of low molecular weight be achieved between extracellular DNA protection (better with high MW) versus efficient intracellular

Buschmann, Michael

319

Chitosan nanoparticles and microspheres for the encapsulation of natural antioxidants extracted from Ilex paraguariensis  

Microsoft Academic Search

The use of chitosan for the encapsulation of active components has gained interest in the last years due to its mucous adhesiveness, non-toxicity, biocompatibility and biodegradability. The benefits of encapsulating active agents in a polymer matrix include their protection from the surrounding medium or processing conditions and their controlled release.In this study chitosan nanoparticles and microspheres were obtained for the

R. Harris; E. Lecumberri; I. Mateos-Aparicio; M. Mengíbar; A. Heras

2011-01-01

320

Chitosan based delivery systems on a length scale: nano to macro  

Microsoft Academic Search

In recent years, chitosan, a biocompatible natural polymer, having a cellulosic backbone has gained much importance in various biomedical applications like wound healing, tissue engineering, surface modifications of the implantable devices and drug delivery. This may be attributed to the versatile chemistry of the polymer. Various chitosan-mediated delivery systems have been developed to improve the bioavailability of drug(s) and be

Kunal Pal; Beauty Behera; Saroj Roy; Sirsendu Sekhar Ray; Goutam Thakur

2011-01-01

321

Agricultural and Forest Meteorology 107 (2001) 167175 Reduction of transpiration through foliar application of chitosan  

E-print Network

Agricultural and Forest Meteorology 107 (2001) 167­175 Reduction of transpiration through foliar of chitosan, a natural beta-1-4-linked glucosamine polymer, to reduce plant transpiration. Chitosan-chambers, where transpiration was measured by weighing pots. In an accompanying field study, water use

Flury, Markus

322

Cell Adsorption and Selective Desorption for Separation of Microbial Cells by Using Chitosan-Immobilized Silica  

Microsoft Academic Search

Cell adsorption and selective desorption for separation of microbial cells were conducted by using chitosan- immobilized silica (CIS). When chitosan was immobilized onto silica surfaces with glutaraldehyde, bacterial cells adsorbed well and retained viability. Testing of the adsorption and desorption ability of CIS using various microbes such as Escherichia coli, Aeromonas hydrophila, Pseudomonas aeruginosa, Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus,

Munehiro Kubota; Masayoshi Matsui; Hiroyuki Chiku; Nobuyuki Kasashima; Manabu Shimojoh; Kengo Sakaguchi

2005-01-01

323

Amperometric phenol biosensor based on laponite clay–chitosan nanocomposite matrix  

Microsoft Academic Search

A novel strategy to fabricate an amperometric biosensor for phenol determination based on chitosan\\/laponite nanocomposite matrix was described. The composite film was used to immobilize PPO on the surface of a glassy carbon electrode. Chitosan was utilized to improve the analytical performance of the pure clay-modified bioelectrode. The biosensor exhibited a series of properties: good affinity to its substrate (the

Quan Fan; Dan Shan; Huaiguo Xue; Yuanyuan He; Serge Cosnier

2007-01-01

324

Crosslinked chitosan nanoparticle formulations for delivery from pressurized metered dose inhalers.  

PubMed

Crosslinked chitosan nanoparticles, prepared using ionic gelation, have been successfully formulated into pressurized metered dose inhalers (pMDIs) with potential for deep lung delivery of therapeutic agents. Nanoparticles were prepared from crosslinked chitosan alone and incorporating PEG 600, PEG 1000 and PEG 5000 for dispersion in aerosol propellant, hydrofuoroalkane (HFA) 227. Spherical, smooth-surfaced, cationic particles of mean size less than 230 nm were produced. Nanoparticles were positively charged and non-aggregated at the pH of the airways. Crosslinked chitosan-PEG 1000 nanoparticles demonstrated greatest dispersibility and physical stability in HFA-227, whereas other formulations readily either creamed or sedimented. Following actuation from pMDIs, the fine particle fraction (FPF) for crosslinked chitosan-PEG 1000 nanoparticles, determined using a next generation impactor, was 34.0±1.4% with a mass median aerodynamic diameter of 4.92±0.3 ?m. The FPFs of crosslinked chitosan, crosslinked chitosan-PEG 600 and crosslinked chitosan-PEG 5000 nanoparticles were 5.7±0.9%, 11.8±2.7% and 17.0±2.1%, respectively. These results indicate that crosslinked chitosan-PEG 1000-based nanoparticles are promising candidates for delivering therapeutic agents, particularly biopharmaceuticals, using pMDIs. PMID:22245573

Sharma, Ketan; Somavarapu, Satyanarayana; Colombani, Agnes; Govind, Nayna; Taylor, Kevin M G

2012-05-01

325

A novel kind of amphoteric composite nanofiltration membrane prepared from sulfated chitosan (SCS)  

Microsoft Academic Search

Sulfated chitosan (SCS), a typical amphoteric polyelectrolyte, was prepared by a homogeneous method. A novel kind of amphoteric composite nanofiltration (NF) membrane was prepared by coating the aqueous solution of sulfated chitosan onto a PAN UF membrane, subsequently crosslinked with glutaraldehyde. The effects of the membrane preparation techniques and operating conditions on the rejection performance of the composite membranes were

Jing Miao; Guo-hua Chen; Cong-jie Gao

2005-01-01

326

Copper on Chitosan: A Recyclable Heterogeneous Catalyst for Azide-alkyne Cycloaddition Reactions in Water  

EPA Science Inventory

Copper sulfate is immobilized over chitosan by simply stirring an aqueous suspension of chitosan in water with copper sulfate; the ensuing catalyst has been utilized for the azide-alkyne cycloaddition in aqueous media and it can be recycled and reused many time without loosing it...

327

Ruthenium on chitosan: A recyclable heterogeneous catalyst for aqueous hydration of nitriles to amides  

EPA Science Inventory

Ruthenium has been immobilized over chitosan by simply stirring an aqueous suspension of chitosan in water with ruthenium chloride and has been utilized for the oxidation of nitriles to amides; the hydration of nitriles occurs in high yield and excellent selectivity, which procee...

328

Biodegradation performance of a chitosan coated magnesium-zinc-tricalcium phosphate composite as an implant.  

PubMed

A Mg-Zn-tricalcium phosphate composite with a chitosan coating was prepared in this investigation to study its biodegradation performance both in vitro and in vivo conditions. The in vitro test results show that the immersion corrosion rate, the pH values of the simulated body fluids and the released metal ion concentration of the chitosan coated composite are all lower than those of the uncoated composite. The in vitro cytotoxicity test shows that the chitosan coated specimens is safe for cellular applications. When the chitosan coated composite is tested in vivo, the concentration of metal ions from the composite observed in the venous blood of Zelanian rabbits is less than the uncoated composite specimens. The chitosan coating slows down the in vivo degradation of the composite after surgery. In vivo testing also indicates that the chitosan coated composite is harmless to important visceral organs, including the heart, kidneys, and liver of the rabbits. The new bone formation surrounding the chitosan coated composite implant shows that the composite improves the concrescence of the bone tissues. The chitosan coating is an effective corrosion resistant layer that reduces the hydrogen release of the implant composite, thereby decreasing the subcutaneous gas bubbles formed. PMID:25280845

Zhao, Jun; Chen, Liangjian; Yu, Kun; Chen, Chang; Dai, Yilong; Qiao, Xueyan; Yan, Yang

2014-09-01

329

Solution casting of chitosan membranes for in vitro evaluation of bioactivity  

PubMed Central

Background Considerable research is focusing on the surface modification of titanium implants for the treatment of orthopaedic tissue injuries to increase the success of orthopaedic fixations. Chitosan is one of the natural materials under investigation based on several favourable properties. Numerous techniques have been described for the preparation of chitosan membranes, including solution casting methods for the investigation of bioactivity before applying coatings onto potential titanium implants. Solution casting enables the easy in-house evaluation of chitosan membranes and allows for the selection of promising chitosan materials. Results We present a method for the standardized and easily applied preparation of chitosan membranes by solution casting. This protocol is suitable for chitosan materials spanning a wide degree of deacetylation, being derived from different chitin sources and chitosan derivatives with novel properties. We detail the preparation and quality control methods in order to prepare membranes with favourable bioactivity, sustaining cell attachment and proliferation for extended culture periods. Conclusions The possibilities associated with the use of chitosan in tissue engineering applications are far from being exhausted and numerous challenges remain prior to successful translation into the clinics. Based on our experience, we have developed simple in-house methods for quality control of homogeneous membrane casting and early prediction of successful experimental outcome. PMID:24192423

2013-01-01

330

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

PubMed

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 ?l/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

Jin, T; Gurtler, J B

2012-08-01

331

Design of optimum response surface experiments for adsorption of direct dye on chitosan  

Microsoft Academic Search

The adsorption of direct dye on chitosan was investigated to assess its efficiency in the treatment of waste water streams from dye works. Adsorption isotherms, which will be of use in the design of Box-Behnken design methods, were also experimentally determined. Analysis of variance has been applied to the experimental isotherms. Chitosan, a chelating polymer, is economically attractive because it

G. Annadurai

2000-01-01

332

Chitosan for coagulation\\/flocculation processes – An eco-friendly approach  

Microsoft Academic Search

Chitosan is a partially deacetylated polymer obtained from the alkaline deacetylation of chitin, a biopolymer extracted from shellfish sources. Chitosan exhibits a variety of physico-chemical and biological properties resulting in numerous applications in fields such as cosmetics, biomedical engineering, pharmaceuticals, ophthalmology, biotechnology, agriculture, textiles, oenology, food processing and nutrition. This amino-biopolymer has also received a great deal of attention in

F. Renault; B. Sancey; P.-M. Badot; G. Crini

2009-01-01

333

Controlled release niosome embedded chitosan system: effect of crosslink mesh dimensions on drug release.  

PubMed

We report on a model chemotherapy drug delivery system comprising nonionic surfactant vesicles (niosomes) packaged within a temperature-sensitive chitosan network. This smart packaging, or package-within-a package system, provides two distinct advantages. First, the gel prevents circulation of the niosomes and maintains delivery in the vicinity of a tumor. Second, the chitosan network protects the niosomes against fluctuations in tonicity, which affects delivery rates. Tonicity is the sum of the concentrations of the solutes which have the capacity to exert an osmotic force across the membrane. All release rate experiments were conducted with 5,6-carboxyfluorescein, a fluorescent dye. Release rates were monitored from both bare niosomes alone and niosome-embedded, chitosan networks. It was observed that chitosan networks prolonged delivery from 100 h to 55 days in low ionic strength environment and pH conditions similar to a tumor site. The primary effect of chitosan is to add control on release time and dosage, and stabilize the niosomes through a high ionic strength surrounding that prevents uncontrolled bursting of the niosomes. Secondary factors include crosslink density of the chitosan network, molecular weight of the individual chitosan polymers, dye concentration within the niosomes, and the number density of niosomes packaged within the chitosan network. Each of these factors can be altered to fine-tune release rates. PMID:22733611

Williams, Eva Christabel; Toomey, Ryan; Alcantar, Norma

2012-12-01

334

Fabric Dyeing with Lichen Parmotrema austrosinence and Improvement of Dyeability by Chitosan Treatment  

Microsoft Academic Search

Three fabrics, 100% silk, nylon and cotton each, were dyed with a lichen dye solution prepared by a fermentation method under conditions of varying dyebath pH and temperature. To verify the effect of chitosan on fabric dyeing, the 100% cotton fabric was treated with a chitosan solution before dyeing. The K\\/S, CIE L*, a*, b*, ?E and Munsell values of

Hye Ja Yoo; Hye Ja Lee; Jeon Sook Rhie

335

Evaluation of the chitosan\\/glycerol-beta-phosphate disodium salt hydrogel application in peripheral nerve regeneration  

Microsoft Academic Search

Research efforts have been devoted to evaluating the application of the chitosan (CS)\\/glycerol-beta-phosphate (GP) disodium salt hydrogel in peripheral nerve regeneration. The gelation time was determined to be 770 s using ultraviolet spectrophotometry. A standard 10 mm long rat sciatic nerve defect model was employed, followed by bridging the proximal and distal stumps with chitosan conduits injected with the Schwann

Lu Zheng; Qiang Ao; Hongyan Han; Xiufang Zhang; Yandao Gong

2010-01-01

336

Evaluation of the chitosan\\/glycerol-?-phosphate disodium salt hydrogel application in peripheral nerve regeneration  

Microsoft Academic Search

Research efforts have been devoted to evaluating the application of the chitosan (CS)\\/glycerol-?-phosphate (GP) disodium salt hydrogel in peripheral nerve regeneration. The gelation time was determined to be 770 s using ultraviolet spectrophotometry. A standard 10 mm long rat sciatic nerve defect model was employed, followed by bridging the proximal and distal stumps with chitosan conduits injected with the Schwann

Lu Zheng; Qiang Ao; Hongyan Han; Xiufang Zhang; Yandao Gong

2010-01-01

337

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

NASA Astrophysics Data System (ADS)

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.

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

2009-01-01

338

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

PubMed

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

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

2013-11-01

339

Production of fungal chitosan from date wastes and its application as a biopreservative for minced meat.  

PubMed

Raw and processed meat contaminated with pathogenic microorganisms is a continuing worldwide problem facing health and industry overseers. Fungal chitosan was extracted, purified and characterized from Aspergillus brasiliensis (niger) ATCC 16404 grown in date syrup (dips) and applied as a potential meat biopreservative. The main features of produced chitosan were a deacetylation degree of 81.3%, a molecular weight of 31,000Da, 96% solubility in 1% acetic acid solution and a harmonized IR-spectrum to standard commercial chitosan. The application of fungal chitosan, as a natural and safe biopreservative for minced meat, was conducted in comparison with potassium sorbate, as a commercial meat preservative. Treated meat samples with 0.02% chitosan was the least trials in microbial contents, i.e. total count, coliforms, ?-glucuronidase-positive Escherichia coli, Enterobacteriaceae, yeasts and molds, Staphylococcus aureus and coagulase positive staphylococci. The antimicrobial activity of fungal chitosan was considerably greater than that of potassium sorbate or their combination at 0.01% from each. Sensory characteristics, e.g. color, odor and texture, of treated meat with chitosan, were higher than those of control and potassium sorbate treated samples. Fungal chitosan, however, could be recommended as a powerful, natural and eco-friendly alternative for meat preservation and overall quality maintenance. PMID:24942991

Tayel, Ahmed A; Ibrahim, Sami I A; Al-Saman, Mahmoud A; Moussa, Shaaban H

2014-08-01

340

A new injectable in situ forming hydroxyapatite and thermosensitive chitosan gel promoted by Na?CO?.  

PubMed

A new injectable in situ forming hydroxyapatite and thermosensitive chitosan gel (chitosan/HA/Na2CO3 gel) promoted by Na2CO3 was preliminarily synthesized. This study was the first to use Na2CO3 as coagulant to construct the chitosan thermosensitive gel. The sol–gel phase transition, degradation, and morphology of the gel were examined. We found that chitosan/HA/Na2CO3 sol with 1.4% Na2CO3 has a suitable gelation time (9 min) and degradation rate. SEM images of the dried gel show a porous netlike framework. TEM, EDS, and XRD were combined to confirm the presence of hydroxyapatite. In vitro cell culture was performed by using rat bone mesenchymal stem cells (rBMSCs). rBMSCs survived well on the chitosan gel scaffold that formed in vitro and in vivo, indicating that the chitosan gel was a suitable substrate for the attachment and proliferation of rBMSCs. Subcutaneous implantation of the chitosan gel formed in situ into a nude mouse revealed that the chitosan gel loaded with rBMSCs could lead to angiogenesis. PMID:24795961

Li, Fangfang; Liu, Yang; Ding, Yun; Xie, Qiufei

2014-04-01

341

Effects of chitosan on oxidative stress and metallothioneins in aquatic worm Tubifex tubifex (Oligochaeta, Tubificidae).  

PubMed

Chitosan is a natural polymer which has the property to elicit the natural defenses mechanism in plant and which can be an interesting biopesticides. It is then necessary to investigate the potential toxicity of chitosan for aquatic animal health. Metallothioneins (MTs) are low molecular weight proteins, mainly implicated in metal ion detoxification. Increase in MTs contents had been considered as a specific biomarker of metal exposure. However recently it has been demonstrated that MTs participate in several cellular functions such as regulation of growth and anti-oxidative defenses. Therefore, the induction of MTs has been investigated in the aquatic worms Tubifex tubifex exposed to chitosan. MTs levels in exposed worm increased significantly (p > 0.05) after 2, 4, and 7 days of exposure to different concentrations of chitosan (maximum + 158.19 +/- 10.2% after 2 days of exposure to 125 mgl(-1) of chitosan). Several antioxidant parameters including glutathione (GSH), glutathione-S-transferase (GST), glutathione reductase (GR), and catalase (CAT) were quantified in T. tubifex after 2, 4, and 7 days of exposure to chitosan. Exposure to chitosan had a negative effect on T. tubifex growth (maximum effect -6.11 +/- 1.6% after 7 days with 125 mgl(-1)) demonstrating the toxic effect of the pesticide. This growth rate decrease was accompanied by a reduction in protein contents. The activity of catalase (CAT), glutathione-S-transferase (GST), and glutathione reductase (GR) increased in response to the chitosan demonstrating an oxidative stress in the worms. PMID:17187843

Mosleh, Yahia Y; Paris-Palacios, Séverine; Ahmed, Mohamed T; Mahmoud, F M; Osman, M A; Biagianti-Risbourg, Sylvie

2007-02-01

342

Functionalization of Titanium with Chitosan via Silanation: Evaluation of Biological and Mechanical Performances  

PubMed Central

Complications in dentistry and orthopaedic surgery are mainly induced by peri-implant bacterial infections and current implant devices do not prevent such infections. The coating of antibacterial molecules such as chitosan on its surface would give the implant bioactive properties. The major challenge of this type of coating is the attachment of chitosan to a metal substrate. In this study, we propose to investigate the functionalization of titanium with chitosan via a silanation. Firstly, the surface chemistry and mechanical properties of such coating were evaluated. We also verified if the coated chitosan retained its biocompatibility with the peri-implant cells, as well as its antibacterial properties. FTIR and Tof-SIMS analyses confirmed the presence of chitosan on the titanium surface. This coating showed great scratch resistance and was strongly adhesive to the substrate. These mechanical properties were consistent with an implantology application. The Chitosan-coated surfaces showed strong inhibition of Actinomyces naeslundii growth; they nonetheless showed a non significant inhibition against Porphyromonas gingivalis after 32 hours in liquid media. The chitosan-coating also demonstrated good biocompatibility to NIH3T3 fibroblasts. Thus this method of covalent coating provides a biocompatible material with improved bioactive properties. These results proved that covalent coating of chitosan has significant potential in biomedical device implantation. PMID:22859940

Renoud, Pauline; Toury, Berangere; Benayoun, Stephane; Attik, Ghania; Grosgogeat, Brigitte

2012-01-01

343

Removal of copper, chromium, and arsenic from CCA-treated wood onto chitin and chitosan  

Microsoft Academic Search

Chitin and chitosan are naturally abundant biopolymers which are of interest to research concerning the sorption of metal ions since the amine and hydroxyl groups on their chemical structures act as chelation sites for metal ions. This study evaluates the removal of copper, chromium, and arsenic elements from chromated copper arsenate (CCA)-treated wood via biosorption by chitin and chitosan. Exposing

S. Nami Kartal; Yuji Imamura

2005-01-01

344

New Insights into Chitosan-DNA Interactions Using Isothermal Titration Microcalorimetry  

E-print Network

New Insights into Chitosan-DNA Interactions Using Isothermal Titration Microcalorimetry Pei Lian Ma of deacetylation (DDA), and molecular weight (Mn) of chitosan, using isothermal titration microcalorimetry (ITC prepared by alkaline deacetylation of chitin found in the shells of crustaceans. It is a linear cationic

Buschmann, Michael

345

Preparation of ion-exchange beads based on poly(methacrylic acid) brush grafted chitosan beads: Isolation of lysozyme from egg white in batch system  

Microsoft Academic Search

Poly(methacrylic acid) brush grafted crosslinked-chitosan (chitosan-g-poly(MAA)) beads were prepared in two sequential steps: in the first step, chitosan beads were prepared by phase-inversion technique and then were crosslinked with epichlorohydrin under alkaline condition; in the second step, the graft copolymerization of methacrylic acid onto the chitosan beads was initiated by ammonium persulfate (APS) under nitrogen atmosphere. The chitosan-g-poly(MAA) beads were

Gülay Bayramo?lu; Gülsüm Ekici; Necati Be?irli; M. Yakup Arica

2007-01-01

346

Chitosan and sodium sulfate as excipients in the preparation of prolonged release theophylline tablets.  

PubMed

The major objectives of this study were to monitor the effect of cross-linking of cationic chitosan in acidic media with sulfate anion during granules preparation by wet granulation method prior to tableting using theophylline (TPH) as a model drug. The prepared granules and the compressed tablets were subjected to in vitro evaluation. The properties of the prepared matrix granules and the compressed tablets were dependent on chitosan:sodium sulfate weight ratios, chitosan content, and molecular weight of chitosan. The prepared granules of all batches showed excellent to passable flowability and were suitable for compression into tablets. Most of the granules were hard and expected to withstand handling during the subsequent compression into tablets. Granules with high friabilities were only those prepared with a high amount of sodium sulfate or low amount of chitosan. Compression of granule batches yield nondisintegrating tablets that showed a decrease in tensile strength with the increase of sodium sulfate content at high chitosan:sodium sulfate weight ratio or with decrease of chitosan content. On the other hand, friability of tablets was increased in the presence of an excessive amount of sodium sulfate and low chitosan content as observed with granules. Slow TPH release from the formulated tablets was achieved at 1:0.5 and 1:1 chitosan:sodium sulfate weight ratios where all or most of the cationic chitosan and sulfate anions were used in a cross-linking reaction during wet granulation. Ratios of 1:2 and 1:3 showed fast drug release, which support the hypothesis that excessive unreacted water-soluble sodium sulfate might increase the porosity of the nondesintegrating tablets during dissolution. Slow drug release was also obtained with high molecular weight chitosan, whereas changing the hardness of the tablets did not significantly change the release profile of the drug as long as the tablets are intact during dissolution. Furthermore, slow drug release was observed as the total amount of chitosan was increased in the formulated tablets. A comparative in vivo study between the chosen formulated tablets (1:1 chitosan:sodium sulfate ratio that contains 10% high molecular weight chitosan) and the commercial Quibron tablets indicated prolonged appearance of the drug in dogs' plasma for both formulations with no significant differences (p > 0.05) in rate and extent of drug absorption. The formulated tablets showed 103.16% bioavailability relative to that of the commercial tablets. PMID:16093204

Alsarra, Ibrahim A; El-Bagory, Ibrahim; Bayomi, Mohsen A

2005-05-01

347

Investigation of Chitosan for Decorporation of 60Co in the Rat  

SciTech Connect

Purpose: The reported investigation is a part of our on-going research aimed at identifying effective in vivo non-toxic decorporation agents and developing new therapies to treat internal contamination with radionuclides. The non-toxic nature of chitosan makes it an especially attractive candidate for unsupervised treatment of the general population in case of radiological/nuclear emergency. In this study, chemically unmodified water-soluble chitosan oligosaccharide of low molecular weight was tested for decorporation of cobalt-60 (Co-60) using a rodent model. Methods: Affinity of chitosan oligosaccharide for Co(II) was tested in vitro under conditions of physiological pH range and ionic strength using combined spectrophotometric and potentiometric titration techniques. Fisher F344 rat model was used for in vivo studies. To evaluate effect of chitosan on ingested Co-60, animals received single oral dose of Co-60 chloride (7 – 13.2 kBq per animal) followed by oral administration of chitosan material (288 – 366 mg per kg body weight); chitosan dosing was repeated in 24 hours. Chitosan was also tested for removal of internalized Co-60. In this study, Co-60 single intravenous injection (7 – 8 kBq per animal) was followed by repetitive oral (300 mg per kg body weight) or intravenous (195 mg per kg body weight) administration of the chitosan material once daily for 5 days. Control animal groups received a single dose of Co-60 without chelator treatment. Excreta was collected daily. Tissues were collected postmortem and analyzed for radioactivity by gamma counting technique. Results: In vitro experiments confirmed binding of Co(II) by chitosan oligosaccharide, formation of mixed cobalt-chitosan-hydroxide complex species was proposed, and stability constants was calculated. Control in vivo studies indicated that about 71% of ingested Co-60 was excreted in two days predominantly through the gastrointestinal tract. For intravenously administered Co-60, urinal excretion was dominant and was found to decrease linearly with time. The oral administration of chitosan appeared to reduce absorption of ingested Co-60; radioactivity in liver and kidney was reduced by over 50%. Intravenously administered chitosan reduced Co-60 levels (after intravenous dosing) in multiple tissues by 15 – 30 %. Decorporation efficacy of oral chitosan was weak. Conclusion: Commercial chemically-unmodified chitosan oligosaccharide exhibited strong potential for the treatment of oral or systemic cobalt exposure. Further studies are warranted to evaluate the dosing regiment.

Levitskaia, Tatiana G.; Creim, Jeffrey A.; Curry, Terry L.; Luders, Teresa; Morris, James E.; Sinkov, Sergey I.; Woodstock, Angela D.; Thrall, Karla D.

2009-08-01

348

Facile Synthesis of Silver Nanoparticles Under {gamma}-Irradiation: Effect of Chitosan Concentration  

SciTech Connect

In the present study, a biopolymer, low molecular weight chitosan had been utilized as a 'green' stabilizing agent for the synthesis of silver nanoparticles under {gamma}-irradiation. The as-synthesized silver nanoparticles have particle diameters in the range of 5 nm-30 nm depending on the percentage of chitosan used (0.1 wt%, 0.5 wt%, 1.0 wt% and 2.0 wt%). It was found that the yield of the silver nanoparticles was in accordance with the concentration of chitosan presence in the solution due to the reduction by the chitosan radical during irradiation. The highly stable chitosan encapsulated silver nanoparticles were characterized using transmission electron microscopy (TEM), UV-Visible spectrophotometer (UV-VIS) and X-ray diffraction spectroscopy (XRD)

Huang, N. M.; Radiman, S.; Ahmad, A.; Idris, H. [Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi (Malaysia); Lim, H. N. [Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Khiew, P. S.; Chiu, W. S.; Tan, T. K. [Faculty of Engineering and Computer Science, Nottingham University, 43500 Semenyih (Malaysia)

2009-06-01

349

Antibacterial effectiveness of chitosan-propolis coated polypropylene films against foodborne pathogens.  

PubMed

Antibacterial properties of chitosan are well documented in the literature. However its antibacterial effectiveness in the film form is controversial due to the methodological differences in test methods used. In this study, antibacterial effectiveness of chitosan-coated polypropylene films alone and incorporating ethanolic extract of propolis (EEP) were evaluated against six foodborne pathogens (Bacillus cereus, Cronobacter sakazakii, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella typhimurium and Staphylococcus aureus) using the ISO 22196 method designed for the antibacterial treated plastic products. The results demonstrated that chitosan coated film exhibited the broad-spectrum antibacterial activity. Incorporation of EPP to coating at 10% (propolis resin/chitosan) enhanced antibacterial activity against all pathogens tested. Results of this study revealed that chitosan has antibacterial activity in the film form and that propolis is a promising antimicrobial for the food packaging applications. PMID:23707735

Torlak, Emrah; Sert, Durmu?

2013-09-01

350

Radiation synthesis and characterization of nanosilver/gelatin/carboxymethyl chitosan hydrogel  

NASA Astrophysics Data System (ADS)

A series of antibacterial hydrogels were fabricated from an aqueous solution of AgNO3, gelatin and carboxymethyl chitosan (CM-chitosan) by radiation-induced reduction and crosslinking at ambient temperature. The nanosilver particles were in situ synthesized accompanying with the formation of gelatin/CM-chitosan hydrogel. Transmission Electron Microscope and UV-vis analysis have verified the formation and homogeneous distribution of nanosilver particles in the hydrogel matrix. The nanosilver/gelatin/CM-chitosan hydrogels possessed interconnected porous structure, had a compressive modulus of 44 to 56 kPa, and could absorb 62 to 108 times of deionized water to its dry weight. Furthermore, the hydrogels were found to have sound antibacterial effect on Escherichia coli (E. coli), and their antibacterial ability could be significantly enhanced by the increasing of AgNO3 content. The comprehensive results of this study suggest that nanosilver/gelatin/CM-chitosan hydrogels have potential as an antibacterial wound dressing.

Zhou, Ying; Zhao, Yinghui; Wang, Lu; Xu, Ling; Zhai, Maolin; Wei, Shicheng

2012-05-01

351

Design and fabrication of a chitosan based integrated optical device for humidity sensing  

NASA Astrophysics Data System (ADS)

Here we report on preparation of planar optical waveguides based on chitosan (DD=80.5%, MW=500kDa) in different salt forms, chitosan/gold nanoparticles, chitosan/gold nanoparticles/silica hybrids with layered structure and modification of Na/K ion-exchange waveguides with thin chitosan/carrageenan multilayers. Chitosan-based optical waveguides with thickness of 0.5- 1.5 ?m were obtained on quartz, glass and MgF2 substrates by spin-coating and dip-coating. For investigation of optical properties, light (wavelength 632 or 532 nm) was coupled into the planar waveguide via the flint glass prism using goniometer. A number of modes, effective refractive index, waveguide propagation losses were determined for all samples in the range of relative humidity 10-99%.

Mironenko, Alexander; Sergeev, Alexander A.; Bratskaya, Svetlana; Nepomnyashiy, Alexander; Avramenko, Valentin; Voznesenskiy, Sergey

2011-09-01

352

Improved mechanical properties of chitosan fibers with applications to degradable radar countermeasure chaff  

NASA Astrophysics Data System (ADS)

The objective of this work has been to improve the mechanical properties of wet spun chitosan fibers for applications to a degradable form of radar countermeasure chaff. The first part of the study characterizes the chitosan used for spinning. Three methods for determining the degree of deacetylation (% DDA) were used and they include titration, elemental analysis, and first derivative ultraviolet (UV) spectrometry. The molecular weight of the chitosan was determined in a solvent system of 0.25 M CH3COOH/0.25 M CH3COONa, using viscometry and gel permeation chromatography (GPC). Several samples of chitosan were used with the % DDA varying from 64.3 to 96.0%. The Mark-Houwink-Sakurada constants used for the determination of viscosity average molecular weight and the universal calibration of the HPLC system were K = 1.40 x 10 -4 dL/g and a = 0.83, respectively. A literature review of molecular weight analysis of chitosan is included. Preliminary wet spinning experiments involved a coagulation rate study which demonstrated that 1 M KOH was an effective coagulant for wet spinning and that the rate of coagulation increases with decreasing solvent ratio in the spin dope. A drying study confirmed the effectiveness of a methanol drying bath followed by a heated roller at 50°C. Following these studies, a wet spinning system was constructed and used. A lack of published data exists concerning the subjects of chitosan fiber spinning and mechanical improvements to both wet and dry chitosan fibers. Several post-spinning modification experiments focused on the reaction of the dried as-spun chitosan fibers with aqueous agents including potassium dihydrogen phosphate (KH2PO4), potassium hydrogen phthalate (KHP), glutaraldehyde (GA), and glyoxal (GLY). For the aqueous buffering agents of KH2PO4, and KHP, the highest mechanical properties resulted from solutions containing phthalate ions at pH 5.00, and from solutions containing phosphate ions at pH 5.39. The best time and temperature for these reactions was 25.8°C and 1 hour reaction time. Substantial gains in mechanical properties were witnessed with an aqueous 0.024 mol/dL solution of GA and an aqueous 0.100 mol/dL solution of GLY after 1 hour at 25.8°C. Reaction time shortened with increasing temperature. Chitosan films were subjected to similar treatments in phosphate and phthalate ion solutions, and also aqueous solutions of GA and GLY. Fourier Transform Infrared (FTIR) spectra of the films suggest that some interaction is occurring between the phosphate ions and the amine group on the chitosan backbone. IR film spectra indicate the presence of a 'C = N' bond in the cases of GA and GLY reacting with chitosan. Extensive published material is available suggesting that the reaction mechanism between chitosan and GA or GLY is either a Schiff's base or an acetyl type reaction. Evidence presented herein proposes a new reaction mechanism for both GA/chitosan and GLY/chitosan systems. A six week environmental experiment involved all of the chemically reacted fibers, along with unreacted chitosan fibers, and chaff fibers, in soil burial, water immersion, and open air environments. Fibers of chitosan, chitosan reacted with KHP(aq.), and chitosan fibers reacted with KH2PO 4 (aq.) degraded completely from sight after 6 weeks in wet soil kept in light conditions. The chaff, GLY/chitosan, and GA/chitosan fibers did not degrade in any of the environments after 6 weeks.

Knaul, Jonathan Zvi

353

Carboxymethyl chitosan: A new water soluble binder for Si anode of Li-ion batteries  

NASA Astrophysics Data System (ADS)

Carboxymethyl chitosan (C-chitosan) is investigated as a new water soluble binder for Si anode of Li-ion batteries. The Fourier transformation infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) measurements reveal that the strong hydrogen bonding is formed between the hydroxylated Si surface and the polar groups (-OH, -COOH and -NH2) of C-chitosan. The Si/C-chitosan anode (Si:carbon black:C-chitosan = 62:30:8 in weight ratio) exhibits a high first discharge capacity (4270 mAh g-1) with a first coulombic efficiency of 89%, and maintains a capacity of 950 mAh g-1 at the current density of 500 mA g-1 over 50 cycles.

Yue, Lu; Zhang, Lingzhi; Zhong, Haoxiang

2014-02-01

354

Sulfated Chitosan Oligosaccharides Suppress LPS-Induced NO Production via JNK and NF-?B Inactivation.  

PubMed

Various biological effects have been reported for sulfated chitosan oligosaccharides, but the molecular mechanisms of action of their anti-inflammatory effects are still unknown. This study aimed to evaluate the anti-inflammatory effects of sulfated chitosan oligosaccharides and to elucidate the possible mechanisms of action. The results showed that pretreated low molecular weight sulfated chitosan oligosaccharides inhibited the production of nitric oxide (NO) and inflammatory cytokines such as IL-6 and TNF-? in lipopolysaccharide (LPS)-activated RAW264.7 cells. The sulfated chitosan oligosaccharides also suppressed inducible nitric oxide synthase (iNOS), phosphorylation of JNK and translocation of p65, a subunit of NF-?B, into the nucleus by inhibiting degradation of I?B-?. Our investigation suggests sulfated chitosan oligosaccharides inhibit IL-6/TNF-? in LPS-induced macrophages, regulated by mitogen-activated protein kinases (MAPKs) pathways dependent on NF-?B activation. PMID:25387351

Kim, Jung-Hyun; Kim, Yon-Suk; Hwang, Jin-Woo; Han, Young-Ki; Lee, Jung-Suck; Kim, Se-Kwon; Jeon, You-Jin; Moon, Sang-Ho; Jeon, Byong-Tae; Bahk, Young Yil; Park, Pyo-Jam

2014-01-01

355

Efficacy of chitosan in inhibiting the oxidation of (+)-catechin in white wine model solutions.  

PubMed

The efficacy of chitosan and sulfites in inhibiting the oxidation of (+)-catechin in aerated model white wines has been compared by monitoring the browning development and the generation of oxidized phenolic compounds. In addition, the protecting effects of these two additives toward the oxidative decay of varietal thiols were investigated. Chitosan effectively contrasted the browning onset in model solutions all along the entire duration of the experimentation. Color development was limited and comparable in both the sulfite and chitosan added samples. Thanks to its polyelectrolyte behavior, chitosan adsorbed up to 80% of the more hydrophilic oxidized phenolic species and chelated 70 and 30% of Fe and Cu added to the solutions, respectively. Thiol oxidation was significantly lowered by chitosan, suggesting that this additive could contribute to maintain the varietal character of wines coming from aromatic grapes and vinified with reduced sulfite amounts. PMID:25234009

Chinnici, Fabio; Natali, Nadia; Riponi, Claudio

2014-10-01

356

Role of pH in metal adsorption from aqueous solutions containing chelating agents on chitosan  

SciTech Connect

The role of pH in adsorption of Cu(II) from aqueous solutions containing chelating agents on chitosan was emphasized. Four chelating agents including ethylenediaminetetraacetic acid (EDTA), citric acid, tartaric acid, and sodium gluconate were used. It was shown that the adsorption ability of Cu(II) on chitosan from its chelated solutions varied significantly with pH variations. The competition between coordination of Cu(II) with unprotonated chitosan and electrostatic interaction of the Cu(II) chelates with protonated chitosan took place because of the change in solution pH during adsorption. The maximum adsorption capacity was obtained within each optimal pH range determined from titration curves of the chelated solutions. Coordination of Cu(II) with the unprotonated chitosan was found to dominate at pH below such an optimal pH value.

Wu, F.C.; Tseng, R.L. [Lien Ho Junior Coll. of Technology, Maio-Li (Taiwan, Province of China). Dept. of Chemical Engineering and Environmental Engineering] [Lien Ho Junior Coll. of Technology, Maio-Li (Taiwan, Province of China). Dept. of Chemical Engineering and Environmental Engineering; Juang, R.S. [Yuan Ze Univ., Chung-li (Taiwan, Province of China)] [Yuan Ze Univ., Chung-li (Taiwan, Province of China)

1999-01-01

357

Chitosan-kaolin coprecipitate as disintegrant in microcrystalline cellulose-based pellets elaborated by extrusion-spheronization.  

PubMed

The usefulness of a coprecipitate of chitosan and kaolin as disintegrant in the pellets of microcrystalline cellulose (MCC) and hydrochlorothiazide (HCT) (as a model of poorly water-soluble drug) produced by extrusion-spheronization was evaluated in this study. The effectiveness of chitosan-kaolin coprecipitate to increase the dissolution rate was compared with that of kaolin and chitosan. A possible synergy effect was also evaluated between the coprecipitate, kaolin or chitosan and sorbitol, added to the pellets as a very water-soluble diluent. The chitosan-kaolin coprecipitate, the kaolin or the chitosan allowed pellets to be obtained of adequate size, roundness, mechanical strength and flow properties. Furthermore, the incorporation of chitosan-kaolin coprecipitate or chitosan significantly increased the dissolution rate of HCT independently of the sorbitol content. The effects on the dissolution of HCT derived from the incorporation of coprecipitate to the pellets can be attributed to its content of chitosan. However, the addition of kaolin into the pellets did not significantly affect the HCT dissolution process. The pellets incorporating coprecipitated chitosan-kaolin or chitosan and the maximum proportion of sorbitol (50%) led to the highest HCT dissolution rate and experienced a rapid and complete disintegration in the dissolution medium. PMID:22309024

Goyanes, Alvaro; Souto, Consuelo; Martínez-Pacheco, Ramón

2013-02-01

358

Synthesis and structure-activity relationship of N-(cinnamyl) chitosan analogs as antimicrobial agents.  

PubMed

The current study focuses on the preparation of new N-(cinnamyl) chitosan derivatives as antimicrobial agents against nine types of crop-threatening pathogens. Chitosan was reacted with a set of aromatic cinnamaldehyde analogs by reductive amination involving formation of the corresponding imines, followed by reduction with sodium borohydride to produce N-(cinnamyl) chitosan derivatives. The structural characterization was confirmed by (1)H and (13)C NMR spectroscopy and the degrees of substitution ranged from 0.08 to 0.28. The antibacterial activity was evaluated in vitro by minimum inhibitory concentration (MIC) against Agrobacterium tumefaciens and Erwinia carotovora. A higher inhibition activity was obtained by N-(?-methylcinnamyl) chitosan with MIC 1275 and 1025 mg/L against A. tumefaciens and E. carotovora, respectively followed by N-(o-methoxycinnamyl) chitosan (MIC=1925 and 1550 mg/L, respectively). The antifungal assessment was evaluated in vitro by mycelial radial growth technique against Alternaria alternata, Botrytis cinerea, Botryodiplodia theobromae, Fusarium oxysporum, Fusarium solani, Pythium debaryanum and Phytophthora infestans. N-(o-methoxycinnamyl) chitosan showed the highest antifungal activity among the tested compounds against the airborne fungi A. alternata, B. cinerea, Bd. theobromae and Ph. infestans with EC?? of 672, 796, 980 and 636 mg/L, respectively. However, N-(p-N-dimethylaminocinnamyl) chitosan was the most active against the soil born fungi F. oxysporum, F. solani and P. debaryanum (EC50=411, 566 and 404 mg/L, respectively). On the other hand, the chitosan derivatives caused significant reduction in spore germination of A. alternata, B. cinerea, F. oxysporum and F. solani compared to chitosan and the reduction in spore germination was higher than that of the mycelia inhibition. The synthesis and characterization of new chitosan derivatives are ongoing in our laboratory aiming to obtain derivatives with higher antimicrobial activities and used as safe alternatives to harmful microbicides. PMID:23511055

Badawy, Mohamed E I; Rabea, Entsar I

2013-06-01

359

The effect of radiation on the thermal properties of chitosan/mimosa tenuiflora and chitosan/mimosa tenuiflora/multiwalled carbon nanotubes (MWCNT) composites for bone tissue engineering  

NASA Astrophysics Data System (ADS)

The purpose of this study is to examine the effect of gamma radiation and UV radiation on the microstructure, chemical structure and thermal stability of Chitosan/Mimosa Tenuiflora and Chitosan/Mimosa Tenuiflora/MWCNT composites scaffolds produced by thermally induced phase separation. The composites were irradiated and observed to undergo radiation-induced degradation through chain scission. Morphology, thermal properties and effects on chemical and semi-crystalline structures were obtained by scanning electronic microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), FT-IR analysis and X-ray Diffraction. A relationship between radiation type and the thermal stability of the composites, were also established. This relationship allows a more accurate and precise control of the life span of Chitosan/Mimosa Tenuiflora and Chitosan/Mimosa Tenuiflora/MWCNT composites through the use of radiation in materials for use in tissue engineering.

Martel-Estrada, S. A.; Santos-Rodríguez, E.; Olivas-Armendáriz, I.; Cruz-Zaragoza, E.; Martínez-Pérez, C. A.

2014-07-01

360

Fusion of a Novel Genetically Engineered Chitosan Affinity Protein and Green Fluorescent Protein for Specific Detection of Chitosan In Vitro and In Situ  

PubMed Central

Chitin is the second most abundant polysaccharide, present, e.g., in insect and arthropod exoskeletons and fungal cell walls. In some species or under specific conditions, chitin appears to be enzymatically de-N-acetylated to chitosan—e.g., when pathogenic fungi invade their host tissues. Here, the deacetylation of chitin is assumed to represent a pathogenicity mechanism protecting the fungus from the host's chitin-driven immune response. While highly specific chitin binding lectins are well known and easily available, this is not the case for chitosan-specific probes. This is partly due to the poor antigenicity of chitosan so that producing high-affinity, specific antibodies is difficult. Also, lectins with specificity to chitosan have been described but are not commercially available, and our attempts to reproduce the findings were not successful. We have, therefore, generated a fusion protein between a chitosanase inactivated by site-directed mutagenesis, the green fluorescent protein (GFP), and StrepII, as well as His6 tags for purification and detection. The recombinant chitosan affinity protein (CAP) expressed in Escherichia coli was shown to specifically bind to chitosan, but not to chitin, and the affinity increased with decreasing degree of acetylation. In vitro, CAP detection was possible either based on GFP fluorescence or using Strep-Tactin conjugates or anti-His5 antibodies. CAP fluorescence microscopy revealed binding to the chitosan exposing endophytic infection structures of the wheat stem rust fungus, but not the chitin exposing ectophytic infection structures, verifying its suitability for in situ chitosan staining. PMID:22367086

Nampally, Malathi; Moerschbacher, Bruno Maria

2012-01-01

361

Swelling kinetics of spray-dried chitosan acetate assessed by magnetic resonance imaging and their relation to drug release kinetics of chitosan matrix tablets  

Microsoft Academic Search

Magnetic resonance imaging (MRI) was used to assess in situ swelling behaviors of spray-dried chitosan acetate (CSA) in 0.1N HCl, pH 6.8 and pH 5.0 Tris–HCl buffers. The in vitro drug releases from CSA matrix tablets containing the model drugs, diclofenac sodium and theophylline were investigated in all media using USP-4 apparatus. The effect of chitosan molecular weight, especially in

Kampanart Huanbutta; Pornsak Sriamornsak; Sontaya Limmatvapirat; Manee Luangtana-anan; Yasuo Yoshihashi; Etsuo Yonemochi; Katsuhide Terada; Jurairat Nunthanid

2011-01-01

362

Chitosan-Based Nanoparticles in Cancer Therapy  

Microsoft Academic Search

\\u000a In recent years, many nanotechnology platforms in the area of medical biology, including cancer therapy, have attracted remarkable\\u000a attention. In particular, research in targeted, polymeric nanoparticles for cancer therapy has increased dramatically in the\\u000a past 5–10 years. However, the potential success of nanoparticles in the clinic relies on consideration of important parameters\\u000a such as nanoparticle fabrication strategies, their physical properties, drug

Vinoth-Kumar Lakshmanan; K. Snima; Joel Bumgardner; Shantikumar Nair; Rangasamy Jayakumar

363

Absorbent alginate fibres modified with hydrolysed chitosan for wound care dressings--II. Pilot scale development.  

PubMed

Fibres have been used extensively in wound dressing applications as they provide a high surface area for absorption, ease of fabrication and softness. It is common practice for commercial wound dressings to be produced from natural materials, such a marine polysaccharides, as they are predominantly biocompatible, non-toxic, and often display bioactive properties, such as inherent antimicrobial activity. In this study hydrolysed chitosans were utilised as a sole coagulant for the production of alginate-chitosan fibres via a one-step, direct wet-spinning extrusion process. The levels of chitosan incorporated into the fibres were analysed quantitatively via elemental analysis and qualitatively by staining using Amido Black 10B. It was estimated that the fibres contained between 4.50 and 5.10% (wt.%) chitosan. The presence of chitosan improved tensile properties such as elongation and tenacity of the base alginate fibres. The increased incorporation of chitosan into the fibres also improved the absorption of the fibres in both saline and distilled water; reaching maximum of >30 g/g and >50 g/g, respectively. This work suggests that the observed hydrolysed chitosan content within the fibre may be optimal for the preparation of a novel fibre for wound care application. PMID:24507364

Sweeney, I R; Miraftab, M; Collyer, G

2014-02-15

364

Effects of chitosan and oligochitosan on development and mitochondrial function of Rhizopus stolonifer.  

PubMed

The antifungal activities of chitosan and oligochitosan have been used to control postharvest decay of the fruits. The effect of chitosan and oligochitosan on mycelium growth, spore germination, and mitochondrial function of Rhizopus stolonifer was evaluated in order to establish a connection between fungus development and the main organelle in charge to provide energy to the cell. The mycelium growth of R. stolonifer was significantly reduced on minimum media amended with chitosan or oligochitosan. The highest antifungal indexes were obtained on media containing chitosan or oligochitosan at 2.0?mg?ml(-1). Microscopic observation showed that chitosan and oligochitosan affected the spore germination and hyphae morphology. Both polymers increased oxygen consumption of R. stolonifer. Respiratory activity was restored with NADH in permeabilized treated and untreated cells, and was inhibited with rotenone and flavones. Complex III and IV were inhibited by antimycin A and cyanide, respectively, in treated and untreated cells. Chitosan and oligochitosan increased NADH dehydrogenase activity in isolated mitochondria. However, there were not changes in the cytochrome c oxidase and ATPase activities by effect of these polymers. These results suggest that both chitosan and oligochitosan affect the development of R. stolonifer and might be implicated in the mitochondrial dysfunction. PMID:24771597

Robles-Martínez, Leobarda; Guerra-Sánchez, María Guadalupe; Hernández-Lauzardo, Ana Niurka; Pardo, Juan Pablo; Velázquez-del Valle, Miguel Gerardo

2014-07-01

365

Photochemical and antimicrobial properties of silver nanoparticle-encapsulated chitosan functionalized with photoactive groups.  

PubMed

Chitosan was functionalized with 4-((E)-2-(3-hydroxynaphthalen-2-yl)diazen-1-yl)benzoic acid by the coupling of the hydroxyl functional groups of chitosan with carboxylic acid group of the dye by DCC coupling method. The silver nanoparticles were prepared by sol-gel method of nanoparticle synthesis. Silver nanoparticle-encapsulated functionalized chitosan was prepared by the phase transfer method. The products were characterized by FTIR, UV-Vis, fluorescence and NMR spectroscopic methods and by SEM and TEM analysis. The photochemical properties of silver nanoparticle-encapsulated chitosan functionalized with 4-((E)-2-(3-hydroxynaphthalen-2-yl)diazen-1-yl)benzoic acid was studied in detail. The light-fastening properties of the chromophoric system was enhanced when attached to chitosan, and it can be further improved by the encapsulation of silver nanoparticles. The antibacterial analysis of silver nanoparticle-encapsulated functionalized chitosan was carried out against Staphylococcus aureus and Escherichia coli and against fungal species such as Aspergillus flavus and Aspergillus terreus. This study showed that silver nanoparticles-encapsulated functionalized chitosan can be used for antibacterial and antifungal applications. PMID:23910360

Mathew, Thomas V; Kuriakose, Sunny

2013-10-01

366

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

PubMed

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

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

2014-11-26

367

Chitosan beads as barriers to the transport of azo dye in soil column.  

PubMed

The development of chitosan-based materials as useful adsorbent polymeric matrices is an expanding field in the area of adsorption science. Although chitosan has been successfully used for the removal of dyes from aqueous solutions, no consideration is given to the removal of dyes from contaminated soils. Therefore this study focuses on the potential use of chitosan as an in situ remediation technology. The chitosan beads were used as barriers to the transport of a reactive dye (Reactive Black 5, RB5) in soil column experiments. Batch sorption experiments, kinetic and equilibrium, were performed to estimate the sorption behavior of both chitosan and soil. The chitosan beads were prepared in accordance with published literature and a synthetic soil was prepared by mixing quantities of sand, silt and clay. The synthetic soil was classified according to British Standards. Calcium chloride was used as tracer to define transport rates and other physical experimental parameters. Dye transport reaction parameters were determined by fitting dye breakthrough curves (BTCs) to the HYDRUS-1D version 4.xx software. Fourier Transform-Infra Red (FT-IR) spectroscopy was used to reveal the sorption mechanism. The study showed that chitosan exhibited a high sorption capacity (S(max)=238 mg/g) and pseudo-first sorption rate (k(1)=1.02 h(-1)) coupled with low swelling and increased retardation for the azo dye tested. Thus it has potential as a Permeable Reactive Barrier (PRB) for containment and remediation of contaminated sites. PMID:19740603

Lazaridis, Nikolaos K; Keenan, Helen

2010-01-15

368

Novel chitosan-based pH-sensitive and disintegrable polyelectrolyte nanogels.  

PubMed

A novel approach to design pH-sensitive and disintegrable polyelectrolyte nanogels composed of citraconic-based N-(carboxyacyl) chitosan (polyanion) and quaternary chitosan (polycation) was reported. Firstly, the hydrolysis of citraconic-modified chitosan was monitored using fluorescamine assay and it could selectively dissociate in acidic media (e.g., pH ?5.0) due to the isomerization during the addition of citraconic anhydride to chitosan. Secondly, the self-assembly behaviors of different polyelectrolyte pairs between citraconic-based chitosan and quaternary chitosan were investigated via colloidal titration assay. It was indicated that the difference in molecular weight (MW) of opposite charged polyelectrolytes played an important role on the formation of polyelectrolyte nanogels. Results showed that polyelectrolyte nanogels (ca. 300nm in size) only formed when polyanion and polycation had a very large difference in MW. The pH-sensitive behavior of polyelectrolyte nanogels was comprehensively investigated by dynamic light scattering (DLS) and transmission electron microscope (TEM). The incorporation of charge-conversional citraconic-based chitosan into polyelectrolyte complexes has provided an effective approach to prepare polyelectrolyte nanogels which were very stable at neutral pH but disintegrated quickly in acidic media. PMID:25042598

Yuan, Fang; Wang, Shasha; Chen, Gaojian; Tu, Kehua; Jiang, Hongliang; Wang, Li-Qun

2014-10-01

369

Improved postharvest quality in patagonian squash ( Cucurbita moschata) coated with radiation depolymerized chitosan  

NASA Astrophysics Data System (ADS)

Different molecular weight chitosans were evaluated on the decay of coated Anquito squashes ( Cucurbita moschata) as well as the maintenance of the fruit quality along five storage months. The original chitosan (Mw=391 kDa, 83% DD), was depolymerized by gamma radiation. Apart from chain scission, other chemical changes were not detected by FTIR or UV-vis analyses. The molecular weight characterization of chitosans was done by size exclusion chromatography with dual light scattering and concentration detection (SEC-MALLS-RI). The coating effectiveness was evaluated on the following parameters: fungal decay incidence, weight loss, firmness, total reducing sugar, soluble solid, flesh color, carotene content, pH and titratable acidity. No sign of fungal decay was observed in squashes coated with 122 and 56 kDa chitosans, which were also the most effective treatments in reducing the weight loss. The chitosan with Mw=122 kDa was also the best treatment considering firmness, internal aspect, sugar and carotene content. Then, radiation degraded chitosan was better in C. moschata preservation than the original chitosan.

Pugliese, Maria Alicia; Goitia, Maria Teresa; Yossen, Mariana; Cifone, Norma; Agulló, Enrique; Andreucetti, Noemi

2011-12-01

370

Synthesis, Characterization, and Antibacterial Activity of Cross-Linked Chitosan-Glutaraldehyde  

PubMed Central

This present study deals with synthesis, characterization and antibacterial activity of cross-linked chitosan-glutaraldehyde. Results from this study indicated that cross-linked chitosan-glutaraldehyde markedly inhibited the growth of antibiotic-resistant Burkholderia cepacia complex regardless of bacterial species and incubation time while bacterial growth was unaffected by solid chitosan. Furthermore, high temperature treated cross-linked chitosan-glutaraldehyde showed strong antibacterial activity against the selected strain 0901 although the inhibitory effects varied with different temperatures. In addition, physical-chemical and structural characterization revealed that the cross-linking of chitosan with glutaraldehyde resulted in a rougher surface morphology, a characteristic Fourier transform infrared (FTIR) band at 1559 cm?1, a specific X-ray diffraction peak centered at 2? = 15°, a lower contents of carbon, hydrogen and nitrogen, and a higher stability of glucose units compared to chitosan based on scanning electron microscopic observation, FTIR spectra, X-ray diffraction pattern, as well as elemental and thermo gravimetric analysis. Overall, this study indicated that cross-linked chitosan-glutaraldehyde is promising to be developed as a new antibacterial drug. PMID:23670533

Li, Bin; Shan, Chang-Lin; Zhou, Qing; Fang, Yuan; Wang, Yang-Li; Xu, Fei; Han, Li-Rong; Ibrahim, Muhammad; Guo, Long-Biao; Xie, Guan-Lin; Sun, Guo-Chang

2013-01-01

371

In vivo efficacy of a chitosan/IL-12 adjuvant system for protein-based vaccines  

PubMed Central

Vaccines based on recombinant proteins require adjuvant systems in order to generate Th1-type immune responses. We have developed a vaccine adjuvant system using a viscous chitosan solution and interleukin (IL)-12, a Th1-inducing cytokine. The chitosan solution is designed to create a depot of antigen and IL-12 at a subcutaneous injection site. We measured the in vivo immune response of a vaccine containing 0.25, 1, or 4 ?g murine IL-12 and 75 ?g ovalbumin (OVA), formulated in a 1.5% chitosan glutamate solution. The chitosan/IL-12/OVA vaccine, in comparison to chitosan/OVA, IL-12/OVA, or OVA alone, elicited greater antigen-specific CD4+ and CD8+ T-cell responses, as determined by CD4+ splenocyte proliferation, Th1 cytokine release, CD8+ T cell interferon-? release, and MHC class I peptide pentamer staining. The combination of chitosan and IL-12 also enhanced IgG2a and IgG2b antibody responses to OVA. Co-formulation of chitosan and IL-12 thus promoted the generation of a Th1 immune response to a model protein vaccine. PMID:20965561

Heffernan, Michael J.; Zaharoff, David A.; Fallon, Jonathan K.; Schlom, Jeffrey; Greiner, John W.

2010-01-01

372

A mediator-free glucose biosensor based on glucose oxidase/chitosan/?-zirconium phosphate ternary biocomposite.  

PubMed

A novel glucose oxidase/chitosan/?-zirconium phosphate (GOD/chitosan/?-ZrP) ternary biocomposite was prepared by co-intercalating glucose oxidase (GOD) and chitosan into the interlayers of ?-zirconium phosphate (?-ZrP) via a delamination-reassembly procedure. The results of X-ray diffraction, infrared spectroscopy, circular dichroism, and ultraviolet spectrum characterizations indicated not only the layered and hybrid structure of the GOD/chitosan/?-ZrP ternary biocomposite but also the recovered activity of the intercalated GOD improved by the co-intercalated chitosan. By depositing the GOD/chitosan/?-ZrP biocomposite film onto a glassy carbon electrode, the direct electrochemistry of the intercalated GOD was achieved with a fast electron transfer rate constant, k(s), of 7.48±3.52 s(-1). Moreover, this GOD/chitosan/?-ZrP biocomposite modified electrode exhibited a sensitive response to glucose in the linear range of 0.25-8.0 mM (R=0.9994, n=14), with a determination limit of 0.076 mM. PMID:24135657

Liu, Li-Min; Wen, Jiwu; Liu, Lijun; He, Deyong; Kuang, Ren-yun; Shi, Taqing

2014-01-15

373

Functional enhancement of chitosan and nanoparticles in cell culture, tissue engineering, and pharmaceutical applications  

PubMed Central

As a biomaterial, chitosan has been widely used in tissue engineering, wound healing, drug delivery, and other biomedical applications. It can be formulated in a variety of forms, such as powder, film, sphere, gel, and fiber. These features make chitosan an almost ideal biomaterial in cell culture applications, and cell cultures arguably constitute the most practical way to evaluate biocompatibility and biotoxicity. The advantages of cell cultures are that they can be performed under totally controlled environments, allow high throughput functional screening, and are less costly, as compared to other assessment methods. Chitosan can also be modified into multilayer composite by combining with other polymers and moieties to alter the properties of chitosan for particular biomedical applications. This review briefly depicts and discusses applications of chitosan and nanoparticles in cell culture, in particular, the effects of chitosan and nanoparticles on cell adhesion, cell survival, and the underlying molecular mechanisms: both stimulatory and inhibitory influences are discussed. Our aim is to update the current status of how nanoparticles can be utilized to modify the properties of chitosan to advance the art of tissue engineering by using cell cultures. PMID:22934070

Gao, Wenjuan; Lai, James C. K.; Leung, Solomon W.

2012-01-01

374

The biocompatible polysaccharide chitosan enhances the oral tolerance to type II collagen  

PubMed Central

Chitosan is a mucoadhesive polysaccharide that promotes the transmucosal absorption of peptides and proteins. At mucosal sites chitosan exhibits immunomodulatory activities and stimulates the release of regulatory cytokines. Herein we evaluated the effect of the co-administration of chitosan in the tolerance to type II collagen (CII) using an experimental model of arthritis. Rats were fed diluent (acetic acid), 1 mg CII, 1 mg chitosan or 1 mg CII + 1 mg chitosan during 5 days before immunization with CII in Freund's complete adjuvant. Systemic effects were evaluated in draining lymph nodes after antigenic challenge or during the clinical evolution of arthritis. Specific antibodies, proliferation against CII and the production of interferon (IFN)-? and interleukin-10 were assessed. Clinical signs were observed 13–15 days after primary immunization. The CII : chitosan group presented the lowest incidence and developed moderate arthritis, with reduced levels of immunoglobulin (Ig)G2a anti-CII, a limited proliferation in draining lymph nodes and a lower release of IFN-? after restimulation with CII. Our results demonstrate that chitosan enhances the tolerance to an articular antigen with a decrease in the inflammatory responses and, as a consequence, an improvement in clinical signs. PMID:19076832

Porporatto, C; Canali, M M; Bianco, I D; Correa, S G

2009-01-01

375

Thiolated chitosan: development and in vivo evaluation of an oral delivery system for leuprolide.  

PubMed

The aim of the present study was to develop an oral delivery system for the peptide drug leuprolide. Gel formulations based on unmodified chitosan/reduced glutathione (GSH) and chitosan-thioglycolic acid (chitosan-TGA)/GSH were prepared, and their effect on the absorption of leuprolide was evaluated in vitro and in vivo in male Sprague Dawley rats. Transport studies were performed with freshly excised rat intestinal mucosa mounted in Ussing-type chambers. Due to the addition of gel formulations comprising 0.5% (m/v) unmodified chitosan/0.5% (m/v) GSH and 0.5% (m/v) chitosan-TGA/0.5% (m/v) GSH, the transport of leuprolide across excised mucosa was improved up to 2.06-fold and 3.79-fold, respectively, in comparison with leuprolide applied in buffer (P(app)=2.87 ± 0.77 × 10?? cm/s). In vivo, the addition of oral gel formulation comprising 8 mg of unmodified chitosan, 1mg of GSH and 1mg of leuprolide increased the area under the plasma concentration-time curve (AUC???) of leuprolide 1.39-fold in comparison with leuprolide having been administered just in saline. Moreover, the administration of oral gel formulation comprising 8 mg of chitosan-TGA, 1mg of GSH and 1mg of leuprolide resulted in a further enhanced leuprolide plasma concentration, and the area under the plasma concentration-time curve (AUC???) of leuprolide was increased 3.72-fold in comparison with the control. With the oral gel formulation comprising 8 mg of chitosan-TGA, a relative bioavailability (versus s.c. injection) of 4.5% was achieved in contrast to the control displaying a relative bioavailability of 1.2%. Thus, according to the achieved results, it is suggested that chitosan-TGA in combination with GSH is a valuable tool for improving the oral bioavailability of the peptide drug leuprolide. PMID:21964316

Iqbal, Javed; Shahnaz, Gul; Perera, Glen; Hintzen, Fabian; Sarti, Federica; Bernkop-Schnürch, Andreas

2012-01-01

376

A comparison of physicochemical properties of sterilized chitosan hydrogel and its applicability in a canine model of periodontal regeneration.  

PubMed

Chitosan has previously been exploited as a scaffold in tissue engineering processes. To avoid infection, chitosan must be sterilized prior to contact with bodily fluids or blood. Previous research has shown that autoclaved chitosan solution lead to decreased molecular weight, dynamic viscosity, and rate of gelling. We prepared a thermosensitive chitosan hydrogel using autoclaved chitosan powder (121°C, 10min) and ?-glycerophosphate (chitosan-PA/GP) and compared the physicochemical properties and biocompatibility in vitro with autoclaved chitosan solution/GP hydrogel. The chitosan-PA/GP hydrogel had a shortened gelation time, higher viscosity, increased water absorption, appropriate degradation time, porous structure, and no obvious cytotoxicity on human periodontal ligament cells. Scanning electron microscopy demonstrated that the cells exhibited a normal morphology. The chitosan-PA/GP hydrogel promoted periodontal tissue regeneration in dog class III furcation defects. The chitosan-PA/GP thermosensitive hydrogel displayed suitable physicochemical properties and biocompatibilities and represents a promising candidate as an injectable tissue engineering scaffold. PMID:25256481

Zang, Shengqi; Dong, Guangying; Peng, Bo; Xu, Jie; Ma, Zhiwei; Wang, Xinwen; Liu, Lingxia; Wang, Qintao

2014-11-26

377

Development and characterization of chitosan/silica nanocomposite membranes  

NASA Astrophysics Data System (ADS)

Quaternized Chitosan/silica based composite membranes were prepared for pervaporation dehydration of water-ethanol mixture. Silica content in membrane matrix has been systematically optimized to control the nanostructure of the developed polymer matrix for studying the effects of molecular structure on the swelling, and PV performance. Among prepared membranes, 40% silica composite membrane shows the remarkable results for the water removal from water/ethanol mixture (80% ethanol + 20% water (w/w)). Contact angle measurement support the PV data as nature of CH-3 membrane is more hydrophilic comparative to others. SEM micrographs show the surface uniformity of the membranes.

Kumar, Amit; Gahlot, Swati; Kulshrestha, Vaibhav; Shahi, V. K.

2014-04-01

378

Synthesis and characterization of some acyl thiourea derivatives of chitosan and their biocidal activities.  

PubMed

Three acyl derivatives of chitosan (CS) with different side chains were synthesized and their structures were characterized. Their swelling behavior was investigated. The antifungal behavior of these chitosan derivatives was investigated in vitro on the mycelial growth, sporulation and germination of conidia or sclerotia of the sugar-beet pathogens, Rhizoctonia solani K"uhn (AG2-2) and Sclerotium rolfsii Sacc. All the prepared derivatives had a significant inhibiting effect on the different stages of development on the germination of conidia or sclerotia of all the investigated fungi. In the absence of chitosan and its derivative, R. solani exhibited the fastest growth of the fungi studied. PMID:25002014

Elkholy, Said S; Salem, Hend A; Eweis, Mohamed; Elsabee, Maher Z

2014-09-01

379

Chitosan as matrix for bio-polymer dispersed liquid crystal systems.  

PubMed

The obtaining of bio-polymer dispersed liquid crystal (bio-PDLC) systems based on a chitosan polymer matrix is reported here for the first time. The new PDLC composites have been obtained by encapsulation of 4-cyano-4'-pentylbiphenyl (5CB) as low molecular weight liquid crystal into chitosan, and they have been characterized by polarized optical microscopy, differential scanning calorimetry, electron and transmission scanning microscopy, Raman and fluorescence spectroscopy. Submicrometric liquid crystalline droplets with uniform size distribution and density have been obtained for low liquid crystal content into the PDLCs. The droplets have a radial configuration being anchored into chitosan matrix by an interface ordering coupling phenomenon. PMID:23618234

Marin, Luminita; Popescu, Maria-Cristina; Zabulica, Andrei; Uji-I, Hiroshi; Fron, Eduard

2013-06-01

380

Ascorbyl palmitate-loaded chitosan nanoparticles: characteristic and polyphenol oxidase inhibitory activity.  

PubMed

The aim of this study was to produce ascorbyl palmitate (AP)-loaded nanoparticles in order to inhibit polyphenol oxidase (PPO) in bananas. AP-loaded chitosan nanoparticles were prepared using acetic acid and citric acid (denoted as CS/AA and CS/CA nanoparticles, respectively). As the initial AP concentration increases, the particle size significantly decreases, and the zeta potential, entrapment and loading efficiency significantly increases. The PPO inhibitory activity of AP was effectively improved when AP was nano-encapsulated by chitosan compared to no encapsulation. These results suggest that chitosan nano-encapsulation can be used to enhance the PPO inhibitory activity of AP. PMID:23247266

Kim, Mi Kyung; Lee, Ji-Soo; Kim, Kwang Yup; Lee, Hyeon Gyu

2013-03-01

381

Mechanical response and multilevel structure of biomimetic hydroxyapatite\\/polygalacturonic\\/chitosan nanocomposites  

Microsoft Academic Search

Using an in situ mineralization process that is biomimetic we have synthesized new nanocomposites of chitosan\\/hydroxyapatite in 50–50 ratio(ChiHAP50), polygalacturonic acid\\/hydroxyapatite in 50–50 ratio (PgAHAP50) and Chitosan\\/hydroxyapatite\\/Polygalacturonic acid (ChiPgAHAP50). Polygalacturonic acid (PgA) is electrostatically complementary to chitosan, and thus is expected to provide stronger interfacial interactions and improve mechanical response. Atomic force imaging of fractured and polished surfaces suggests a

Devendra Verma; Kalpana S. Katti; Dinesh R. Katti; Bedabibhas Mohanty

2008-01-01

382

Thiol modified chitosan self-assembled monolayer platform for nucleic acid biosensor.  

PubMed

A self-assembled monolayer (SAM) of thiol modified chitosan (SH-CHIT), with thioglycolic acid (TGA) as a modifier to bestow thiol groups, has been prepared onto gold (Au)-coated glass plates for fabrication of the nucleic acid biosensor. The chemical modification of CHIT via TGA has been evidenced by Fourier transform infrared spectroscopy (FT-IR) studies, and the biocompatibility studies reveal that CHIT retains its biocompatible nature after chemical modification. The electrochemical studies conducted onto SH-CHIT/Au electrode reveal that thiol modification in CHIT amino end enhances the electrochemical behavior indicating that it may be attributed to delocalization of electrons in CHIT skeleton that participates in the resonance process. The carboxyl group modified end of DNA probe has been immobilized onto SH-CHIT/Au electrode using N-ethyl-N'-(3-dimethylaminopropyl)carbodimide (EDC) and N-hydroxysuccinimide (NHS) chemistry for detection of complementary, one-base mismatch and non-complementary sequence using electrochemical and optical studies for Mycobacterium tuberculosis detection. It has been found that DNA-SH-CHIT/Au bioelectrode can specifically detect 0.01 ?M of target DNA concentration with sensitivity of 1.69?×?10(-6) A ?M(-1). PMID:25205172

Mukherjee, Maumita Das; Solanki, Pratima R; Sumana, Gajjala; Manaka, Takaaki; Iwamoto, Mitsumasa; Malhotra, Bansi D

2014-10-01

383

Eudragit S-100 entrapped chitosan microspheres of valdecoxib for colon cancer.  

PubMed

COX-2 inhibitors have demonstrated beneficial effects in colorectal cancer. The purpose of this study was to prepare and evaluate the colon specific microspheres of COX-2 inhibitors using valdecoxib as a model drug. Mucoadhesive core microspheres were prepared using chitosan as polymer and entrapped within Eudragit S 100 for colon targeting. FTIR spectrum of selected, coated microspheres showed peaks of valdecoxib at 3377, 3250, 1334 and 1155 cm(-1). XRD showed amorphous character and DSC showed depressed broad endotherm of valdecoxib at 169.07 degrees C, which may be attributed to dilution effect by the amorphous polymer. The coated microspheres were spherical with an average size of 90 mum. Storage of the microspheres at 40 degrees C/75% relative humidity for 6 months indicated no significant drug degradation. The coated microspheres did neither release the drug in acidic pH of stomach (pH 1.2) nor in small intestinal pH between 5 to 6.8, and the release started at pH 7.4, indicting perfect colonic delivery. The coated microspheres pretreated with phosphate buffer pH 7.4 for 30 min, when applied to mucosal surface of freshly excised goat colon, showed good mucoadhesion. The drug release at pH 7.4 and good mucoadhesive property of the microspheres make the system ideal for colonic delivery. PMID:20535630

Thakral, Naveen K; Ray, Alok R; Majumdar, Dipak K

2010-09-01

384

A Proteomic View to Characterize the Effect of Chitosan Nanoparticle to Hepatic Cells: Is Chitosan Nanoparticle an Enhancer of PI3K/AKT1/mTOR Pathway?  

PubMed Central

Chitosan nanoparticle, a biocompatible material, was used as a potential drug delivery system widely. Our current investigation studies were the bioeffects of the chitosan nanoparticle uptake by liver cells. In this experiment, the characterizations of chitosan nanoparticles were measured by transmission electron microscopy and particle size analyzer. The average size of the chitosan nanoparticle was 224.6 ± 11.2?nm, and the average zeta potential was +14.08 ± 0.7?mV. Moreover, using proteomic approaches to analyze the differential protein expression patterns resulted from the chitosan nanoparticle uptaken by HepG2 and CCL-13 cells identified several proteins involved in the PI3K/AKT1/mTOR pathway. Our experimental results have demonstrated that the chitosan nanoparticle may involve in the liver cancer cell metastasis and proliferation. PMID:24757677

Yuan, Shyng-Shiou; Huang, Ying-Fong; Lin, Po-Chiao; Lu, Chi-Yu

2014-01-01

385

Sputter target  

DOEpatents

The disclosure relates to an improved sputter target for use in the deposition of hard coatings. An exemplary target is given wherein titanium diboride is brazed to a tantalum backing plate using a gold-palladium-nickel braze alloy.

Gates, Willard G. (Kansas City, MO); Hale, Gerald J. (Overland Park, KS)

1980-01-01

386

Controlled release behaviors of chitosan/?, ?-glycerophosphate thermo-sensitive hydrogels  

NASA Astrophysics Data System (ADS)

Chitosan/?, ?-glycerophosphate (CS/?, ?-GP) thermo-sensitive hydrogels presented flowable solution state at low temperature and semisolid hydrogel when the ambient temperature increased. In this research, different concentrations of metronidazole encapsulated, CS and ?, ?-GP, as well as different acid solvents, were chosen to evaluate their influences on the drug release behaviors from CS/?, ?-GP hydrogels. It was found that there was a sustaining release during the first 3 h followed by a plateau. SEM images showed that drugs were located both on the surface and in the interior of hydrogels. The optimal preparation conditions of this hydrogel for drug release were as follows: 1.8% (w/v) CS in HAc solvent, 5.6% (w/v) ?, ?-GP and 5 g/L metronidazole encapsulation. Cytotoxicity evaluation found no toxic effect. In order to control the release rate, 2.5 g/L chitosan microspheres with spherical shape and smooth surface were incorporated, and it was found that the initial release process was alleviated, while drug concentration had no obvious effect on the release rate. It could be concluded that the metronidzole release behaviors could be optimized according to practical applications.

Liu, Wei-Fang; Kang, Chuan-Zhen; Kong, Ming; Li, Yang; Su, Jing; Yi, An; Cheng, Xiao-Jie; Chen, Xi-Guang

2012-09-01

387

Surface studies of microcrystalline chitosan/poly(vinyl alcohol) mixtures  

NASA Astrophysics Data System (ADS)

In the present study, the surface properties of microcrystalline chitosan (MCCh), poly(vinyl alcohol) (PVA) and MCCh/PVA blends (made from acetic acid solutions with the MCCh concentration ranging from 20% to 80%) have been studied by the tapping-mode atomic force microscopy (AFM), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The changes of topography images are considered by determining the root mean square (RMS, Rq) deviation in the image data. For PVA samples, the transition between adjacent lamellae occurs through holes, islands, and bicontinuous structures. The AFM images showed also the lamellar structure of PVA in the blend. The crystalline topography of MCCh/PVA film surface suggests the presence of PVA on the top surface. The FTIR spectra of film blends, in the amide I and II region of MCCh and the hydroxyl stretching bands of PVA have been analyzed. FTIR analysis showed the existence of a weak interaction of the hydroxyl or amino groups of microcrystalline chitosan with hydroxyl groups of PVA.

Lewandowska, Katarzyna

2012-12-01

388

Substrate specificity and enzyme recycling using chitosan immobilized laccase.  

PubMed

The immobilization of laccase (Aspergillus sp.) on chitosan by cross-linking and its application in bioconversion of phenolic compounds in batch reactors were studied. Investigation was performed using laccase immobilized via chemical cross-linking due to the higher enzymatic operational stability of this method as compared to immobilization via physical adsorption. To assess the influence of different substrate functional groups on the enzyme's catalytic efficiency, substrate specificity was investigated using chitosan-immobilized laccase and eighteen different phenol derivatives. It was observed that 4-nitrophenol was not oxidized, while 2,5-xylenol, 2,6-xylenol, 2,3,5-trimethylphenol, syringaldazine, 2,6-dimetoxyphenol and ethylphenol showed reaction yields up 90% at 40 °C. The kinetic of process, enzyme recyclability and operational stability were studied. In batch reactors, it was not possible to reuse the enzyme when it was applied to syringaldazne bioconversion. However, when the enzyme was applied to bioconversion of 2,6-DMP, the activity was stable for eight reaction batches. PMID:25329872

Skoronski, Everton; Fernandes, Mylena; Magalhães, Maria de Lourdes Borba; da Silva, Gustavo Felippe; João, Jair Juarez; Soares, Carlos Henrique Lemos; Júnior, Agenor Fúrigo

2014-01-01

389

Mucoadhesive nanoparticles made of thiolated quaternary chitosan crosslinked with hyaluronan.  

PubMed

Mucoadhesive polymeric nanoparticles intended for drug transport across the gastrointestinal mucosa were prepared from quaternary ammonium-chitosan conjugates synthesised from reduced-MW chitosan (32 kDa). Conjugates contained pendant moieties of 2-4 adjacent diethyl-dimethylene-ammonium groups substituted on repeating units (26-55%). Conjugates were thiolated via amide bonds with thioglycolic acid to yield products with thiol content in the 35-87 ?mol/g range. Nanoparticles with mean size in the 270-370 nm range and positive zeta-potential (+3.7 to +12.5 mV) resulted from ionotropic gelation of the thiolated conjugates with de-polymerised hyaluronic acid (470 kDa). The nanoparticles were fairly stable in size and thiol content and showed a significant mucoadhesivity, matching and even exceeding that of the constituent polymers. Nanoparticles were internalised by endothelial progenitor cells in direct relation to their surface charge intensity. Nanoparticle uptake significantly improved cell viability and resistance to oxidation. The lyophilised nanoparticles were re-dispersible and could make a manageable formulation for oral use. PMID:23218262

Zambito, Ylenia; Felice, Francesca; Fabiano, Angela; Di Stefano, Rossella; Di Colo, Giacomo

2013-01-30

390

Chitosan microbeads for encapsulation of thyme (Thymus serpyllum L.) polyphenols.  

PubMed

In this work chitosan microbeads were prepared by emulsion technique and loaded with thyme polyphenols by diffusion from an external aqueous solution of Thymus serpyllum L. The effects of concentrations of chitosan (1.5-3% (w/v)) and GA (glutaraldehyde) (0.1-0.4% (v/v)), as a crosslinking agent on the main properties of microbeads were assessed. The obtained microgel beads from ? 220 to ? 790 ?m in diameter were exposed to controlled drying process at air (at 37 °C) after which they contracted to irregular shapes (? 70-230 ?m). The loading of dried microbeads with polyphenols was achieved by swelling in the acidic medium. The swelling rate of microbeads decreased with the increase in GA concentration. Upon this rehydration, thyme polyphenols were effectively encapsulated (active load of 66-114 mg GAE g(beads)(-1)) and the microbeads recovered a spherical shape. Both, the increase in the amount of the crosslinking agent and the presence of polyphenols, contributed to a more pronounced surface roughness of microbeads. The release of encapsulated polyphenols in simulated gastrointestinal fluids was prolonged to 3h. PMID:25037430

Trifkovi?, Kata T; Milašinovi?, Nikola Z; Djordjevi?, Verica B; Kruši?, Melina T Kalagasidis; Kneževi?-Jugovi?, Zorica D; Nedovi?, Viktor A; Bugarski, Branko M

2014-10-13

391

Chitosan-Alginate Biocomposite Containing Fucoidan for Bone Tissue Engineering  

PubMed Central

Over the last few years, significant research has been conducted in the construction of artificial bone scaffolds. In the present study, different types of polymer scaffolds, such as chitosan-alginate (Chi-Alg) and chitosan-alginate with fucoidan (Chi-Alg-fucoidan), were developed by a freeze-drying method, and each was characterized as a bone graft substitute. The porosity, water uptake and retention ability of the prepared scaffolds showed similar efficacy. The pore size of the Chi-Alg and Chi-Alg-fucoidan scaffolds were measured from scanning electron microscopy and found to be 62–490 and 56–437 µm, respectively. In vitro studies using the MG-63 cell line revealed profound cytocompatibility, increased cell proliferation and enhanced alkaline phosphatase secretion in the Chi-Alg-fucoidan scaffold compared to the Chi-Alg scaffold. Further, protein adsorption and mineralization were about two times greater in the Chi-Alg-fucoidan scaffold than the Chi-Alg scaffold. Hence, we suggest that Chi-Alg-fucoidan will be a promising biomaterial for bone tissue regeneration. PMID:24441614

Venkatesan, Jayachandran; Bhatnagar, Ira; Kim, Se-Kwon

2014-01-01

392

Chitosan-alginate biocomposite containing fucoidan for bone tissue engineering.  

PubMed

Over the last few years, significant research has been conducted in the construction of artificial bone scaffolds. In the present study, different types of polymer scaffolds, such as chitosan-alginate (Chi-Alg) and chitosan-alginate with fucoidan (Chi-Alg-fucoidan), were developed by a freeze-drying method, and each was characterized as a bone graft substitute. The porosity, water uptake and retention ability of the prepared scaffolds showed similar efficacy. The pore size of the Chi-Alg and Chi-Alg-fucoidan scaffolds were measured from scanning electron microscopy and found to be 62-490 and 56-437 µm, respectively. In vitro studies using the MG-63 cell line revealed profound cytocompatibility, increased cell proliferation and enhanced alkaline phosphatase secretion in the Chi-Alg-fucoidan scaffold compared to the Chi-Alg scaffold. Further, protein adsorption and mineralization were about two times greater in the Chi-Alg-fucoidan scaffold than the Chi-Alg scaffold. Hence, we suggest that Chi-Alg-fucoidan will be a promising biomaterial for bone tissue regeneration. PMID:24441614

Venkatesan, Jayachandran; Bhatnagar, Ira; Kim, Se-Kwon

2014-01-01

393

Free-standing polyelectrolyte membranes made of chitosan and alginate  

PubMed Central

Free-standing films have increasing applications in the biomedical field as drug delivery systems, for wound healing and tissue engineering. Here, we prepared free-standing membranes by the layer-by-layer assembly of chitosan and alginate, two widely used biomaterials. Our aim was to produce thick membrane, to study the permeation of model drugs and the adhesion of muscle cells. We first defined the optimal growth conditions in terms of pH and alginate concentration. The membranes could be easily detached from polystyrene or polypropylene substrate without any post-processing step. They dry thickness was varied over a large range from 4 to 35 ?m. A two-fold swelling was observed by confocal microscopy when they were immersed in PBS. In addition, we quantified the permeation of model drugs (fluorescent dextrans) through the free standing membrane, which depended on the dextran molecular weight. Finally, we showed that myoblast cells exhibited a preferential adhesion on the alginate-ending membrane as compared to the chitosan-ending membrane or to the substrate side. PMID:23590116

Caridade, Sofia G.; Monge, Claire; Gilde, Flora; Boudou, Thomas; Mano, Joao F.; Picart, Catherine

2014-01-01

394

Bacterial growth on chitosan-coated polypropylene textile.  

PubMed

Biofouling is a problem common in all systems where microorganisms and aqueous environment meet. Prevention of biofouling is therefore important in many industrial processes. The aim of this study was to develop a method to evaluate the ability of material coating to inhibit biofilm formation. Chitosan-coated polypropylene nonwoven textile was prepared using dielectric barrier discharge plasma activation. Resistance of the textile to biofouling was then tested. First, the textile was submerged into a growth medium inoculated with green fluorescein protein labelled Pseudomonas aeruginosa. After overnight incubation at 33°C, the textile was observed using confocal laser scanning microscopy for bacterial enumeration and biofilm structure characterisation. In the second stage, the textile was used as a filter medium for prefiltered river water, and the pressure development on the in-flow side was measured to quantify the overall level of biofouling. In both cases, nontreated textile samples were used as a control. The results indicate that the chitosan coating exhibits antibacterial properties. The developed method is applicable for the evaluation of the ability to inhibit biofilm formation. PMID:23724330

Erben, D; Hola, V; Jaros, J; Rahel, J

2012-01-01

395

Bacterial Growth on Chitosan-Coated Polypropylene Textile  

PubMed Central

Biofouling is a problem common in all systems where microorganisms and aqueous environment meet. Prevention of biofouling is therefore important in many industrial processes. The aim of this study was to develop a method to evaluate the ability of material coating to inhibit biofilm formation. Chitosan-coated polypropylene nonwoven textile was prepared using dielectric barrier discharge plasma activation. Resistance of the textile to biofouling was then tested. First, the textile was submerged into a growth medium inoculated with green fluorescein protein labelled Pseudomonas aeruginosa. After overnight incubation at 33°C, the textile was observed using confocal laser scanning microscopy for bacterial enumeration and biofilm structure characterisation. In the second stage, the textile was used as a filter medium for prefiltered river water, and the pressure development on the in-flow side was measured to quantify the overall level of biofouling. In both cases, nontreated textile samples were used as a control. The results indicate that the chitosan coating exhibits antibacterial properties. The developed method is applicable for the evaluation of the ability to inhibit biofilm formation. PMID:23724330

Erben, D.; Hola, V.; Jaros, J.; Rahel, J.

2012-01-01

396

Development and characterization of an edible composite film based on chitosan and virgin coconut oil with improved moisture sorption properties.  

PubMed

An edible composite film was prepared from an emulsion system based on chitosan and virgin coconut oil (VCO). The effect of incorporation of VCO was evaluated at various concentrations and the optimum concentration was chosen based on resultant changes in the properties of the film. Addition of VCO in film forming solution resulted in increase in film thickness and marginal reduction in film transparency. Compatibility of VCO with chitosan was better at lower concentration of VCO as indicated by the microstructure of composite film in scanning electron micrographs. Phase separation was evident at higher level of oil incorporation and the optimal oil/chitosan ratio was determined to be at 0.5 to 1 mL/g chitosan. Furthermore, chemical interaction took place between VCO and chitosan as revealed by Fourier transform infrared spectroscopy data. Even though control chitosan films exhibited superior gas barrier properties, composite film with optimum VCO concentration revealed better mechanical and moisture sorption properties. PMID:23464980

Binsi, P K; Ravishankar, C N; Srinivasa Gopal, T K

2013-04-01

397

In-vivo tumor targeting of pluronic-based nano-carriers.  

PubMed

Pluronic-based nano-carriers including bare forms that were composed of Pluronic F 68(NC(PF 68)) or Pluronic F 127(NC(PF 127)), and chitosan-conjugated forms (Chito-NC(PF 68) or Chito-NC(PF 127)) were prepared by photo-polymerizing two kinds of diacrylated Pluronic (F 68 and F 127) and acrylated chitosan to investigate the effect of chitosan conjugation and their physicochemical characteristics (size and hydrophilicity) of Pluronic-based nano-carriers on the tumor targeting efficiency. All of the nano-carriers were stable in serum-containing media without forming any aggregation and did not show any acute cytotoxicity to both normal (NIH3T3 fibroblast) and tumor (SCC7) cells. Chitosan conjugation did not change their sizes or thermo-sensitive properties of the nano-carriers, but significantly increased their in-vitro cellular uptake compared to the corresponding bare forms. The in-vivo tumor accumulation of these nano-carriers was optically monitored by using Cy5.5-attached nano-carriers in SCC7 tumor-bearing mice. For all cases, local accumulation of the injected nano-carriers in liver was not dominant compared to the tumor site, demonstrating good tumor targeting efficacy of the Pluronic-based nano-carriers. Among different samples, chitosan-conjugated nano-carriers showed much better tumor accumulation than bare forms, and mostly remained up to 72h, implying prolonged blood circulation and more efficient tumor accumulation. Between Chito-NC(PF 68) and Chito-NC(PF 127), Chito-NC(PF 68) showed a little better tumor accumulation and retention, suggesting the difference in Pluronic, thus difference in hydrophilicity and the size of the nano-carriers also might affect the tumor targeting. In contrast, bare nano-carriers were initially accumulated well in tumor, but they were excreted from the tumor site relatively rapidly. Therefore, chitosan-functionalization was very effective for improving the tumor targeting efficacy of Pluronic-based nano-carriers. PMID:20600404

Kim, Ja-Young; Choi, Won Il; Kim, Young Ha; Tae, Giyoong; Lee, Seung-Young; Kim, Kwangmeyung; Kwon, Ick Chan

2010-10-01

398

Curcumin-containing liposomes stabilized by thin layers of chitosan derivatives.  

PubMed

Stable vesicles for efficient curcumin encapsulation, delivery and controlled release have been obtained by coating of liposomes with thin layer of newly synthesized chitosan derivatives. Three different derivatives of chitosan were obtained and studied: the cationic (by introduction of the stable, quaternary ammonium groups), the hydrophobic (by attachment of N-dodecyl groups) and cationic-hydrophobic one (containing both quaternary ammonium and N-dodecyl groups). Zeta potential measurements confirmed effective coating of liposomes with all these chitosan derivatives. The liposomes coated with cationic-hydrophobic chitosan derivative are the most promising curcumin carriers; they can easily penetrate cell membrane and release curcumin in a controlled manner. Biological studies indicated that such systems are non-toxic for murine fibroblasts (NIH3T3) while toxic toward murine melanoma (B16F10) cell line. PMID:23668985

Karewicz, Anna; Bielska, Dorota; Loboda, Agnieszka; Gzyl-Malcher, Barbara; Bednar, Jan; Jozkowicz, Alicja; Dulak, Jozef; Nowakowska, Maria

2013-09-01

399

Mechanical and dye adsorption properties of graphene oxide/chitosan composite fibers prepared by wet spinning.  

PubMed

Graphene oxide/chitosan composite fibers were prepared by a wet spinning method, and their mechanical properties were investigated. Experimental results showed that the introduction of graphene oxide at 4 wt% loading can improve the tensile strengths of chitosan fibers. Batch adsorption experiments were carried out to study the effect of various parameters, such as the initial pH value, adsorbent dosage, contact time and temperature on adsorption of fuchsin acid dye. The Langmuir model was used to fit the experimental data of adsorption isotherm, and kinetic studies showed that the adsorption data followed the pseudo-second order model. Thermodynamic studies indicated that the adsorption of fuchsin acid dye on graphene oxide/chitosan fibers was a spontaneous and exothermic process. Our results indicate that the graphene oxide/chitosan fibers have excellent mechanical properties and can serve as a promising adsorbent for the removal of dyes from aqueous solutions. PMID:24507344

Li, Yanhui; Sun, Jiankun; Du, Qiuju; Zhang, Luhui; Yang, Xiaoxia; Wu, Shaoling; Xia, Yanzhi; Wang, Zonghua; Xia, Linhua; Cao, Anyuan

2014-02-15

400

Xyloglucan-block-poly(?-caprolactone) copolymer nanoparticles coated with chitosan as biocompatible mucoadhesive drug delivery system.  

PubMed

The development of novel xyloglucan-block-poly(?-caprolactone) (XGO-b-PCL) nanoparticles coated with the mucoadhesive polysaccharide chitosan is described. XGO-b-PCL nanoparticles show monodisperse size distribution (Rh ?=?50 nm). Curcumin is successfully encapsulated within the PCL core within drug to polymer ratio of 1:5 (w/w). The coating of nanoparticles with chitosan results in an increased particle size and positive surface charge due to the polycation nature of the chitosan. Mucoadhesive properties of chitosan-coated nanoparticles are demonstrated by its exceptional ability to interact with mucin through electrostatic forces. Finally, in vitro studies show that curcumin-loaded nanoparticles exhibit higher cytotoxic effects against B16F10 melanoma cells than L929 fibroblast cells. PMID:24469965

Mazzarino, Letícia; Otsuka, Issei; Halila, Sami; Bubniak, Lorena dos Santos; Mazzucco, Suelen; Santos-Silva, Maria C; Lemos-Senna, Elenara; Borsali, Redouane

2014-05-01