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1

Targeted gadolinium-loaded dendrimer nanoparticles for tumor-specific magnetic resonance contrast enhancement.  

PubMed

A target-specific MRI contrast agent for tumor cells expressing high affinity folate receptor was synthesized using generation five (G5) ofpolyamidoamine (PAMAM) dendrimer. Surface modified dendrimer was functionalized for targeting with folic acid (FA) and the remaining terminal primary amines of the dendrimer were conjugated with the bifunctional NCS-DOTA chelator that forms stable complexes with gadolinium (Gd III). Dendrimer-DOTA conjugates were then complexed with GdCl3 followed by ICP-OES as well as MRI measurement of their longitudinal relaxivity (T1 s(-1) mM(-1)) of water. In xenograft tumors established in immunodeficient (SCID) mice with KB human epithelial cancer cells expressing folate receptor (FAR), the 3D MRI results showed specific and statistically significant signal enhancement in tumors generated with targeted Gd(III)-DOTA-G5-FA compared with signal generated by non-targeted Gd(III)-DOTA-G5 contrast nanoparticle. The targeted dendrimer contrast nanoparticles infiltrated tumor and were retained in tumor cells up to 48 hours post-injection of targeted contrast nanoparticle. The presence of folic acid on the dendrimer resulted in specific delivery of the nanoparticle to tissues and xenograft tumor cells expressing folate receptor in vivo. We present the specificity of the dendrimer nanoparticles for targeted cancer imaging with the prolonged clearance time compared with the current clinically approved gadodiamide (Omniscan) contrast agent. Potential application of this approach may include determination of the folate receptor status of tumors and monitoring of drug therapy. PMID:18686779

Swanson, Scott D; Kukowska-Latallo, Jolanta F; Patri, Anil K; Chen, Chunyan; Ge, Song; Cao, Zhengyi; Kotlyar, Alina; East, Andrea T; Baker, James R

2008-01-01

2

Targeted gadolinium-loaded dendrimer nanoparticles for tumor-specific magnetic resonance contrast enhancement  

PubMed Central

A target-specific MRI contrast agent for tumor cells expressing high affinity folate receptor was synthesized using generation five (G5) of polyamidoamine (PAMAM) dendrimer. Surface modified dendrimer was functionalized for targeting with folic acid (FA) and the remaining terminal primary amines of the dendrimer were conjugated with the bifunctional NCS-DOTA chelator that forms stable complexes with gadolinium (Gd III). Dendrimer-DOTA conjugates were then complexed with GdCl3 followed by ICP-OES as well as MRI measurement of their longitudinal relaxivity (T1 s?1 mM?1) of water. In xenograft tumors established in immunodeficient (SCID) mice with KB human epithelial cancer cells expressing folate receptor (FAR), the 3D MRI results showed specific and statistically significant signal enhancement in tumors generated with targeted Gd(III)-DOTA-G5-FA compared with signal generated by non-targeted Gd(III)-DOTA-G5 contrast nanoparticle. The targeted dendrimer contrast nanoparticles infiltrated tumor and were retained in tumor cells up to 48 hours post-injection of targeted contrast nanoparticle. The presence of folic acid on the dendrimer resulted in specific delivery of the nanoparticle to tissues and xenograft tumor cells expressing folate receptor in vivo. We present the specificity of the dendrimer nanoparticles for targeted cancer imaging with the prolonged clearance time compared with the current clinically approved gadodiamide (Omniscan™) contrast agent. Potential application of this approach may include determination of the folate receptor status of tumors and monitoring of drug therapy.

Swanson, Scott D; Kukowska-Latallo, Jolanta F; Patri, Anil K; Chen, Chunyan; Ge, Song; Cao, Zhengyi; Kotlyar, Alina; East, Andrea T; Baker, James R

2008-01-01

3

Integrin ?v?3-targeted dynamic contrast-enhanced magnetic resonance imaging using a gadolinium-loaded polyethylene gycol-dendrimer-cyclic RGD conjugate to evaluate tumor angiogenesis and to assess early antiangiogenic treatment response in a mouse xenograft tumor model.  

PubMed

The purpose of this study was to validate an integrin ?v?3-targeted magnetic resonance contrast agent, PEG-G3-(Gd-DTPA)6-(cRGD-DTPA)2, for its ability to detect tumor angiogenesis and assess early response to antiangiogenic therapy using dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI). Integrin ?v?3-positive U87 cells and control groups were incubated with fluorescein-labeled cRGD-conjugated dendrimer, and the cellular attachment of the dendrimer was observed. DCE MRI was performed on mice bearing KB xenograft tumors using either PEG-G3-(Gd-DTPA)6-(cRGD-DTPA)2 or PEG-G3-(Gd-DTPA)6-(cRAD-DTPA)2. DCE MRI was also performed 2 hours after anti-integrin ?v?3 monoclonal antibody treatment and after bevacizumab treatment on days 3 and 6t. Using DCE MRI, the 30-minute contrast washout percentage was significantly lower in the cRGD-conjugate injection groups. The enhancement patterns were different between the two contrast injection groups. In the antiangiogenic therapy groups, a rapid increase in 30-minute contrast washout percentage was observed in both the LM609 and bevacizumab treatment groups, and this occurred before there was an observable decrease in tumor size. The integrin ?v?3 targeting ability of PEG-G3-(Gd-DTPA)6-(cRGD-DTPA)2 in vitro and in vivo was demonstrated. The 30-minute contrast washout percentage is a useful parameter for examining tumor angiogenesis and for the early assessment of antiangiogenic treatment response. PMID:22954145

Chen, Wei-Tsung; Shih, Tiffany Ting Fang; Chen, Ran-Chou; Tu, Shin-Yang; Hsieh, Wen-Yuen; Yang, Pang-Chyr

4

Development of a gadolinium-loaded LAB-based aqueous scintillator for neutrino detection  

NASA Astrophysics Data System (ADS)

A gadolinium (Gd) complex with carboxylic acid was synthesized by using a neutralization chemical reaction. Gd (0.5%) was doped into a liquid scintillator by using a solvent-solvent extraction under controlled pH. Linear alkyl benzene (LAB) was used as a scintillation solvent. We measured several important physical and optical properties. The preparation, the synthesis procedures and the characterization of the resulting gadolinium-loaded, LAB-based, liquid scintillator are described in this paper.

Yeo, In Sung; Joo, Kyung Kwang; Kim, Bong Keon; So, Sun Heang; Song, Sook Hyung

2013-01-01

5

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

Microsoft Academic Search

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

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

6

A dual-functionally modified chitosan derivative for efficient liver-targeted gene delivery.  

PubMed

Galactosylated chitosan-hydroxypropyltrimethylammonium (gal-HTCC) was synthesized by galactosylating and quaternizing chitosan to endue chitosan with targeting specificity for potential applications as gene vectors. The composition and physicochemical properties of gal-HTCC were characterized by FT-IR, (1) H NMR, elemental analysis, X-ray diffraction, and turbidity measurement. It was found that water-soluble gal-HTCC showed a more amorphous structure than chitosan, and it also had a much better plasmid condensation capability than galactosylated chitosan. Cytotoxicity measurements revealed that gal-HTCC showed significantly lower cytotoxicity in HepG2 and HeLa cell lines compared to branched polyethylenimine (bPEI, 25 kDa) which was used as a positive control. The nanoparticles (NPs) consisted of gal-HTCC and plasmid DNA had desirable particle size (around 250 nm) with a narrow size distribution. Confocal laser scanning microscopy confirmed that NPs could be internalized and transported to the nucleus efficiently within 6 h. In vitro gene transfection results indicated that gal-HTCC had significantly higher transfection efficiency (7- to 32-fold) compared to chitosan and gal-chitosan for targetable delivery of pGL3 luciferase plasmid to HepG2, and its transfection efficiency was highly inhibited in the presence of galactose (20 mM). All these results suggest that gal-HTCC can function as a promising nonviral gene vector for efficient liver-targeted gene delivery. PMID:23203540

Xiao, Bo; Wang, Xiaoyu; Qiu, Zhiye; Ma, Jun; Zhou, Lei; Wan, Ying; Zhang, Shengmin

2012-12-03

7

Targeting to carcinoma cells with chitosan- and starch-coated magnetic nanoparticles for magnetic hyperthermia.  

PubMed

The delivery of hyperthermic thermoseeds to a specific target site with minimal side effects is an important challenge in targeted hyperthermia, which employs magnetic method and functional polymers. An external magnetic field is used to control the site-specific targeting of the magnetic nanoparticles. Polymer-coated magnetic nanoparticles can confer a higher affinity to the biological cell membranes. In this study, uncoated, chitosan-coated, and starch-coated magnetic nanoparticles were synthesized for use as a hyperthermic thermoseed. Each sample was examined with respect to their applications to hyperthermia using XRD, VSM, and FTIR. In addition, the temperature changes under an alternating magnetic field were observed. As in vitro tests, the magnetic responsiveness of chitosan- and starch-coated magnetite was determined by a simple blood vessel model under various intensities of magnetic field. L929 normal cells and KB carcinoma cells were used to examine the cytotoxicity and affinity of each sample using the MTT method. The chitosan-coated magnetic nanoparticles generated a higher DeltaT of 23 degrees C under an AC magnetic field than the starch-coated magnetite, and the capturing rate of the particles was 96% under an external magnetic field of 0.4 T. The highest viability of L929 cells was 93.7%. Comparing the rate of KB cells capture with the rate of L929 cells capture, the rate of KB cells capture relatively increased with 10.8% in chitosan-coated magnetic nanoparticles. Hence, chitosan-coated magnetic nanoparticles are biocompatible and have a selective affinity to KB cells. The targeting of magnetic nanoparticles in hyperthermia was improved using a controlled magnetic field and a chitosan-coating. Therefore, chitosan-coated magnetic nanoparticles are expected to be promising materials for use in magnetic targeted hyperthermia. PMID:18257079

Kim, Dong-Hyun; Kim, Kyoung-Nam; Kim, Kwang-Mahn; Lee, Yong-Keun

2009-01-01

8

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

9

Targeted doxorubicin delivery by chitosan-galactosylated modified polymer microbubbles to hepatocarcinoma cells.  

PubMed

Targeted drug delivery is a main issue in cancer treatment. Taking advantage of recently developed polyvinyl alcohol (PVA)-based microbubbles, which are characterized by chemical versatility of the polymeric surface thereby allowing coating with different ligands, we set up a strategy for the targeted delivery of the anticancer agent doxorubicin to hepatocarcinoma cells. Such microbubbles are exceptionally efficient ultrasound scatterers and thus represent also an option as potential ultrasound contrast agents. Moreover, the oscillation of microbubbles induced by ultrasound could contribute to favor the release of drugs allocated on shell. Specifically, PVA-based microbubbles were reacted with a galactosylated chitosan complex and loaded with doxorubicin to enable the localization and drug delivery to HepG2 hepatocarcinoma cells overexpressing asialoglycoprotein receptors. We demonstrated selectivity and greater bioadhesive properties of the functionalized microbubbles for tumor cells than to normal fibroblasts, which were influenced by the degree of galactosylation. The presence of galactosylated chitosan did not modify the rate of doxorubicin release from microbubbles, whichwas almost complete within 48h. Cellular uptake of doxorubicin loaded on functionalized microbubbles was higher in HepG2 than in normal fibroblasts, which do not over express the asialoglycoprotein receptors. In addition, doxorubicin loaded onto functionalized microbubbles fully retained its cytotoxic activity. Cells were also irradiated with ultrasound, immediately after exposure to microbubbles. An early enhancement of doxorubicin release and cellular drug uptake associated to a concomitant increase in cytotoxicity was observed in HepG2 cells. Overall, results of the study indicate that galactosylated chitosan microbubbles represent promising devices for the targeted delivery of antitumor agents to liver cancer cells. PMID:23759384

Villa, Raffaella; Cerroni, Barbara; Viganò, Lucia; Margheritelli, Silvia; Abolafio, Gabriella; Oddo, Letizia; Paradossi, Gaio; Zaffaroni, Nadia

2013-05-13

10

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

2011-05-06

11

Glycol chitosan/heparin immobilized iron oxide nanoparticles with a tumor-targeting characteristic for magnetic resonance imaging.  

PubMed

We described the preparation of the glycol chitosan/heparin immobilized iron oxide nanoparticles (composite NPs) as a magnetic resonance imaging agent with a tumor-targeting characteristic. The iron oxide nanoseeds used clinically as a magnetic resonance imaging agent were immobilized into the glycol chitosan/heparin network to form the composite NPs. To induce the ionic interaction between the iron oxide nanoseeds and glycol chitosan, gold was deposited on the surface of iron oxide nanoseeds. After the immobilization of gold-deposited iron oxide NPs into the glycol chitosan network, the NPs were stabilized with heparin based on the ionic interaction between cationic glycol chitosan and anionic heparin. FE-SEM (field emission-scanning electron microscopy) and a particle size analyzer were used to observe the formation of the stabilized composite NPs, and a Jobin-Yvon Ultima-C inductively coupled plasma-atomic emission spectrometer (ICP-AES) was used to measure the contents (%) of formed iron oxide nanoseeds as a function of reaction temperature and formed gold deposited on the iron oxide nanoparticles. We also evaluated the time-dependent excretion profile, in vivo biodistribution, circulation time, and tumor-targeting ability of the composite NPs using a noninvasive NIR fluorescence imaging technology. To observe the MRI contrast characteristic, the composite NPs were injected into the tail veins of tumor-bearing mice to demonstrate their selective tumoral distribution. The MR images were collected with conventional T(2)-weighted spin echo acquisition parameters. PMID:21506550

Yuk, Soon Hong; Oh, Keun Sang; Cho, Sun Hang; Lee, Beom Suk; Kim, Sang Yoon; Kwak, Byung-Kook; Kim, Kwangmeyung; Kwon, Ick Chan

2011-05-03

12

Comparison of PLGA and lecithin/chitosan nanoparticles for dermal targeting of betamethasone valerate.  

PubMed

Poly(lactide-co-glycolide) (PLGA) and lecithin/chitosan (LC) nanoparticles were prepared to evaluate the difference in the behavior upon administration on skin, for steroidal treatment. For this purpose, betamethasone-17-valerate (BMV)-loaded nanoparticles with a narrow size distribution and high entrapment efficiency were prepared. Permeation studies showed that both polymeric nanoparticles enhanced the amount of BMV in epidermis, which is the target site of topical steroidal treatment, when compared with commercial formulation. 1.58-Fold increase was determined in the epidermis concentration of BMV by LC nanoparticles with respect to PLGA nanoparticles. Nanoparticles were diluted in chitosan gel (10%, w/w) to prepare suitable formulation for topical application. Accumulation from both gel formulations were found significantly higher than commercial formulation in skin layers (p < 0.05). In addition, pharmacodynamic responses were also investigated as anti-inflammatory and skin-blanching parameters. Both formulations significantly improved these parameters although they contained 10 times less amount of BMV than commercial cream. Moreover, TEWL measurement exhibited no barrier function changes upon the application of nanoparticles on skin. Overall, both nanoparticles improved the localization of BMV within skin layers; but when compared with PLGA nanoparticles, the LC nanoparticles could be classified as a better candidate for topical delivery vehicle in the treatment of various dermatological inflammatory diseases. PMID:23390922

Özcan, Ipek; Azizo?lu, Erkan; Senyi?it, Taner; Özyazici, Mine; Özer, Özgen

2013-02-08

13

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

PubMed Central

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

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

2012-01-01

14

A novel method to prepare magnetite chitosan microspheres conjugated with methotrexate (MTX) for the controlled release of MTX as a magnetic targeting drug delivery system.  

PubMed

The purpose of the present study is to develop a new method to prepare magnetite chitosan microspheres conjugated with methotrexate (MTX) for the controlled release of MTX as a magnetic targeting drug delivery system. MTX was first conjugated to the chitosan chain via a peptide bond and then a suspension cross-linking technique was used for the production of magnetic chitosan microspheres with glutaraldehyde as the cross-linker. The MTX-loading capacity of the magnetic chitosan microspheres was determined and drug release experiments were also carried out to discuss the MTX release behavior. All the data support that the magnetic chitosan-MTX microspheres prepared in this method would have great potential application in magnetic targeting drug delivery technology. PMID:19538010

Zhang, Xiaoyu; Chen, Fenghua; Ni, Jiazuan

2009-07-01

15

Investigation on novel chitosan nanoparticle-aptamer complexes targeting TGF-? receptor II.  

PubMed

In our previous study, a dominant sequence called aptamer S58 antagonized TGF-?-induced myofibroblast transdifferentiation in human Tenon's capsule fibroblasts (HTFs) through sealing the targeting site of TGF-? receptor II (T?R II). However, rapid degradation by ubiquitous nucleases limited the aptamer's efficacy. Chitosan-nanoparticles (CS-NP) are good drug carriers. Herein we synthesises novel chitosan nanoparticle-aptamer S58 complexes called CS(S58)-NP in order to preserve and prolong S58's efficacy. We synthesised CS(S58)-NP at various molar ratios of CS-NP to S58 using an ionic gelation method. Then, the properties of the CS(S58)-NP including particle size, zeta potential, protection capacity, slow-release effect and cytotoxicity were studied. The targeting effect of the CS(S58)-NP was also studied. CS(S58)-NP at molar ratios of 20 and 30 showed high aptamer encapsulation efficiency, powerful aptamer protection, stable sustained-release ability and low cytotoxicity. FITC-labelled CS(S58)-NP could successfully bind to T?R II. As a result, TGF-?-induced cell proliferation and ?-SMA expression were both inhibited. Furthermore, the CS(S58)-NP could inhibit TGF-?-induced ?-SMA expression for a longer time than naked S58, even in serum. This research applied CS-NP as the aptamer carrier. The research results demonstrate that CS-NP are potentially able to preserve and prolong aptamer S58's efficacy. This study reveals that the use of CS-NP is promising for aptamer delivery and CS(S58)-NP can be a potential anti-scarring therapeutic approach after glaucoma filtration surgery. PMID:23999222

Chen, Xia; Zhu, Xiaoyan; Li, Lei; Xian, Guangjun; Wang, Wei; Ma, Dawei; Xie, Lin

2013-08-30

16

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.

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

2013-01-01

17

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

PubMed

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

2013-10-01

18

Biodegradable Chitosan Magnetic Nanoparticle Carriers for Sub-Cellular Targeting Delivery of Artesunate for Efficient Treatment of Breast Cancer  

NASA Astrophysics Data System (ADS)

Artesunate is a semi-synthetic derivative of artemisinin, the active principle extracted from Artemisia annua. It possesses good anti-proliferative activity and anti-angiogenic activity with very low toxicity to normal healthy cells. The drawback of most cancer drugs is their inability to accumulate selectively in the cancerous cells. So, large quantities of doses have to be administered to get the required therapeutic concentration in the target site and it resulted in many serious side effects due to the exposure of healthy cells to higher concentrations of cytotoxic drugs. The problem may be solved by selectively and quantitatively accumulating the drug at target site using magnetic nanoparticles guided by an externally applied magnetic field. A modest attempt has been made in this present study, the artesunate magnetic nanoparticle was successfully formulated using two forms of chitosan and evaluated for its in-vitro characteristics like surface morphology, particle size and distribution, zeta potential, magnetic susceptibility, encapsulation efficiency, loading capacity and in-vitro drug release. The synthesized magnetite size was 73 nm and the size of developed magnetic nanoparticles of artesunate was in the range of 90 to 575 nm. Acetic acid soluble chitosan at low concentration exhibit highest encapsulation efficiency and drug loading whereas increase in water soluble chitosan concentration increases the encapsulation efficiency and drug loading in formulations. The developed chitosan magnetic nanoparticles of artesunate shows better release characteristics and may be screened for its in-vivo breast cancer activity.

Subramanian, Natesan; Abimanyu, Sugumaran; Vinoth, Jeevanesan; Sekar, Ponnusamy Chandra

2010-12-01

19

Hyaluronidase enzyme core-5-fluorouracil-loaded chitosan-PEG-gelatin polymer nanocomposites as targeted and controlled drug delivery vehicles.  

PubMed

This study examines the performance of novel hyaluronidase enzyme core-5-fluorouracil-loaded chitosan-polyethylene glycol-gelatin polymer nanocomposites, which were prepared using an ionic gelation technique, as targeted and controlled drug delivery vehicles. These hyaluronidase-loaded nanoparticles have recently been proposed as targeted and controlled drug delivery vehicle systems to tissues due to their ability to loosen the intercellular connective matrix of hyaluronic acid. The encapsulation efficiency and loading capacities of the nanoparticles demonstrated that these nanocomposites displayed sufficient binding ability, which depends on the pH and initial concentration of the drug. The cytotoxic effects of the chitosan-hyaluronidase-5-fluorouracil (CS-HYL-5-FU), chitosan-hyaluronidase-5-fluorouracil polyethylene glycol (CS-HYL-5-FU-PEG), and chitosan-hyaluronidase-5-fluorouracil polyethylene glycol-gelatin (CS-HYL-5-FU-PEG-G) nanoparticles were assessed using MTT assays, and the nanovectors were found to be less cytotoxic than the chemotherapeutic 5-FU after incubation for 3-12h. The particle sizes of the CS-HYL-5-FU, CS-HYL-5-FU-PEG and CS-HYL-5-FU-PEG-G polymer composites were between 300 and 580 nm, as determined by a Zetasizer. Scanning electron microscopy (SEM) analysis indicated that the nanocomposites exhibit a clear, smooth surface and fine morphology. Linkages of the polymers, enzyme, and drug were confirmed by FTIR spectroscopy. Atomic fluorescence microscopy (AFM) analysis confirmed the size of the polymer composite nanoparticles. Therefore, this work established that the drug can be successfully encapsulated in chitosan-polyethylene glycol-gelatin-accompanied hyaluronidase nanoparticles with a homogeneous distribution. These nanoparticles can be potential carriers for targeted and controlled drug delivery to cancer cells. PMID:23796828

Rajan, M; Raj, V; Al-Arfaj, Abdullah A; Murugan, A M

2013-06-21

20

SPION-loaded chitosan-linoleic acid nanoparticles to target hepatocytes.  

PubMed

The aim of this study was to develop a novel polymeric magnetic nanoprobe as an MRI contrast agent to target hepatocytes, as well as to evaluate the targeting ability of the nanoprobe with MRI in vivo. Superparamagnetic iron oxide nanocrystals (SPIONs) were synthesized by a thermal decomposition and seed growth method. An 1-ethyl-3-(3-(dimethylamino)-propyl) carbodiimide (EDC)-mediated reaction coupled water-soluble chitosan (WSC) to linoleic acid (LA). Twelve-nanometer-sized SPIONs were incorporated into the core of self-assembled WSC-LA nanoparticles. The morphology and size distribution of the SPION-loaded WSC-LA nanoparticles (SCLNs) were determined by transmittance electron microscopy (TEM) and dynamic light scattering (DLS), respectively. The encapsulation of SPIONs in the WSC-LA nanoparticles reduced the cytotoxicity of bare iron particles and enhanced their dispersion ability in water. The clustering of SPIONs into WSC-LA nanoparticles showed ultrasensitive magnetic behavior. After in vivo intravascular SCLN injection, MRI revealed relative signal enhancement in the liver. The localization of SCLN in hepatocytes was confirmed by Prussian blue staining and TEM analysis. We have successfully developed an ultrasensitive SCLN that effectively targets hepatocytes. The SCLN can be used as a contrast agent to aid in the diagnosis of hepatic diseases. PMID:19138733

Lee, Chang-Moon; Jeong, Hwan-Jeong; Kim, Se-Lim; Kim, Eun-Mi; Kim, Dong Wook; Lim, Seok Tae; Jang, Kyu Yoon; Jeong, Yong Yeon; Nah, Jae-Woon; Sohn, Myung-Hee

2008-12-24

21

Folate receptor targeted, carboxymethyl chitosan functionalized iron oxide nanoparticles: a novel ultradispersed nanoconjugates for bimodal imaging.  

PubMed

This article delineates the design and synthesis of a novel, bio-functionalized, magneto-fluorescent multifunctional nanoparticles suitable for cancer-specific targeting, detection and imaging. Biocompatible, hydrophilic, magneto-fluorescent nanoparticles with surface-pendant amine, carboxyl and aldehyde groups were designed using o-carboxymethyl chitosan (OCMC). The free amine groups of OCMC stabilized magnetite nanoparticles on the surface allow for the covalent attachment of a fluorescent dye such as rhodamine isothiocyanate (RITC) with the aim to develop a magneto-fluorescent nanoprobe for optical imaging. In order to impart specific cancer cell targeting properties, folic acid and its aminated derivative was conjugated onto these magneto-fluorescent nanoparticles using different pendant groups (-NH(2), -COOH, -CHO). These newly synthesized iron-oxide folate nanoconjugates (FA-RITC-OCMC-SPIONs) showed excellent dispersibility, biocompatibility and good hydrodynamic sizes under physiological conditions which were extensively studied by a variety of complementary techniques. The cellular internalization efficacy of these folate-targeted and its non-targeted counterparts were studied using a folate-overexpressed (HeLa) and a normal (L929 fibroblast) cells by fluorescence microscopy and magnetically activated cell sorting (MACS). Cell-uptake behaviors of nanoparticles clearly demonstrate that cancer cells over-expressing the human folate receptor internalized a higher level of these nanoparticle-folate conjugates than normal cells. These folate targeted nanoparticles possess specific magnetic properties in the presence of an external magnetic field and the potential of these nanoconjugates as T(2)-weighted negative contrast MR imaging agent were evaluated in folate-overexpressed HeLa and normal L929 fibroblast cells. PMID:21331392

Bhattacharya, Dipsikha; Das, Manasmita; Mishra, Debashis; Banerjee, Indranil; Sahu, Sumanta K; Maiti, Tapas K; Pramanik, Panchanan

2011-02-17

22

Chitosan enhances the stability and targeting of immuno-nanovehicles to cerebro-vascular deposits of Alzheimer's disease amyloid protein  

Microsoft Academic Search

Alzheimer's disease amyloid ? (A?) proteins accumulate in the cerebral vasculature and cause cerebral amyloid angiopathy (CAA). The objective of this study was to resolve critical formulation issues in developing nanoparticles (NPs) capable of permeating the blood brain barrier (BBB) and targeting cerebrovascular A? proteins. To achieve this objective we designed immuno-nanovehicles, which are chitosan-coated poly lactic-co-glycolic acid (PLGA) NPs

Kristen M. Jaruszewski; Subramanian Ramakrishnan; Joseph F. Poduslo; Karunya K. Kandimalla

23

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

24

Folate conjugated carboxymethyl chitosan–manganese doped zinc sulphide nanoparticles for targeted drug delivery and imaging of cancer cells  

Microsoft Academic Search

We developed a novel folic acid (FA) conjugated carboxymethyl chitosan coordinated to manganese doped zinc sulphide quantum dot (FA–CMC–ZnS:Mn) nanoparticles. The system can be used for targeting, controlled drug delivery and also imaging of cancer cells. The prepared nanoparticles were characterized using SEM, AFM, FT-IR, UV and DLS studies. The size range of 5-FU encapsulated FA–CMC–ZnS:Mn nanoparticles were from 130

Manjusha Elizabeth Mathew; Jithin C. Mohan; K. Manzoor; S. V. Nair; H. Tamura; R. Jayakumar

2010-01-01

25

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

PubMed Central

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.

2011-01-01

26

Enhancement of the targeting capabilities of the Paclitaxel-loaded pluronic nanoparticles with a glycol chitosan/heparin composite.  

PubMed

An enhancement of tumor-targeting capability was demonstrated with paclitaxel (PTX)-loaded Pluronic nanoparticles (NPs) with immobilized glycol chitosan and heparin. The PTX-loaded Pluronic NPs were prepared as described in our previous report by means of a temperature-induced phase transition in a mixture of Pluronic F-68 and liquid polyethylene glycol (PEG; molecular weight: 400) containing PTX. The liquid PEG is used as the solubilizer of PTX, and Pluronic F-68 is the polymer that encapsulates the PTX. The glycol chitosan and heparin were immobilized on the surface of the Pluronic NPs in an aqueous medium, and a powdery form of the glycol chitosan/heparin immobilized Pluronic NPs (composite NPs) was obtained by freeze-drying. Field emission scanning electron microscopy and a particle size analyzer were used to observe the morphology and size distribution of the prepared NPs. To apply the composite NPs as a delivery system for the model anticancer drug PTX, the release pattern and pharmacokinetic parameters were observed, and the tumor growth was monitored by injecting the composite NPs into the tail veins of tumor-bearing mice. An enhancement of tumor-targeting capability of NPs was verified by using noninvasive live animal imaging technology to observe the time-dependent excretion profile, the in vivo biodistribution, circulation time, and the tumor-targeting capability of composite NPs. PMID:22149139

Yuk, Soon Hong; Oh, Keun Sang; Cho, Sun Hang; Kim, Sang Yoon; Oh, Sangkwon; Lee, Jin Ho; Kim, Kwangmeyung; Kwon, Ick Chan

2011-12-23

27

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

2012-06-12

28

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

PubMed Central

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

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

2012-01-01

29

Targeted delivery of doxorubicin-utilizing chitosan nanoparticles surface-functionalized with anti-Her2 trastuzumab  

PubMed Central

Background Targeting drugs to their sites of action to overcome the systemic side effects associated with most antineoplastic agents is still a major challenge in pharmaceutical research. In this study, the monoclonal antibody, trastuzumab, was used as a targeting agent in nanoparticles carrying the antitumor drug, doxorubicin, specifically to its site of action. Methods Chitosan-doxorubicin conjugation was carried out using succinic anhydride as a crosslinker. Trastuzumab was conjugated to self-assembled chitosan-doxorubin conjugate (CS-DOX) nanoparticles (particle size, 200 nm) via thiolation of lysine residues and subsequent linking of the resulted thiols to chitosan. Conjugation was confirmed by gel permeation chromatography, differential scanning calorimetry, Fourier transform infrared spectroscopy, and 1H nuclear magnetic resonance spectroscopy studies. Dynamic light scattering, transmission electron microscopy, and zeta potential determination were used to characterize the nanoparticles. Results CS-DOX conjugated nanoparticles had a spherical shape and smooth surface with a narrow size distribution and core-shell structure. Increasing the ratio of doxorubicin to chitosan in the conjugation reaction gave rise to a higher doxorubicin content but lower conjugation efficiency. Trastuzumab-decorated nanoparticles (CS-DOX-mAb) contained 47 ?g/mg doxorubicin and 33.5 ?g/mg trastuzumab. Binding of trastuzumab to the nanoparticles was further probed thermodynamically by isothermal titration calorimetry. Fluorescence microscopy demonstrated enhanced and selective uptake of CS-DOX-mAb by Her2+ cancer cells compared with nontargeted CS-DOX nanoparticles and free drug. Conclusion Antibody-conjugated nanoparticles were shown to discriminate between Her2+ and Her2? cells, and thus have the potential to be used in active targeted drug delivery, with reduction of drug side effects in Her2+ breast and ovarian cancers.

Yousefpour, Parisa; Atyabi, Fatemeh; Vasheghani-Farahani, Ebrahim; Movahedi, Ali-Akbar Mousavi; Dinarvand, Rassoul

2011-01-01

30

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.

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

2013-01-01

31

Development and evaluation of rivastigmine loaded chitosan nanoparticles for brain targeting.  

PubMed

The rivastigmine (RHT) loaded chitosan nanoparticles (CS-RHT NPs) were prepared by ionic gelation method to improve the bioavailability and enhance the uptake of RHT to the brain via intranasal (i.n.) delivery. CS-RHT NPs were characterized for particles size, particle size distribution (PDI), encapsulation efficiency, zeta potential and in vitro release study. Nose-to-brain delivery of placebo nanoparticles (CS-NPs) was investigated by confocal laser scanning microscopy technique using rhodamine-123 as a marker. The brain/blood ratio of RHT for different formulations were 0.235, 0.790 and 1.712 of RHT (i.v.), RHT (i.n.), and CS-RHT NPs (i.n.) respectively at 30 min are indicative of direct nose to brain transport bypassing the BBB. The brain concentration achieved from i.n. administration of CS-NPs (966 ± 20.66 ng ml(-1); t(max) 60 min) was significantly higher than those achieved after i.v. administration of RHT sol (387 ± 29.51 ngml(-1); t(max) 30 min), and i.n. administration of RHT solution (508.66 ± 22.50 ng ml(-1); t(max) 60 min). The higher drug transport efficiency (355 ± 13.52%) and direct transport percentage (71.80 ± 6.71%) were found with CS-RHT NPs as compared to other formulation. These results suggest that CS-RHT NPs have better brain targeting efficiency and are a promising approach for i.n. delivery of RHT for the treatment and prevention of Alzheimer's disease (AD). PMID:22561106

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

2012-04-27

32

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

33

Chitosan Enhances the Stability and Targeting of Immuno-Nanovehicles to Cerebro-vascular Deposits of Alzheimer's Disease Amyloid Protein  

PubMed Central

Alzheimer's disease amyloid ? (A?) proteins accumulate in the cerebral vasculature and cause cerebral amyloid angiopathy (CAA). The objective of this study is to resolve critical formulation issues in developing nanoparticles capable of permeating the blood brain barrier (BBB) and targeting cerebrovascular A? proteins. To achieve this objective we designed immuno-nanovehicles, which are chitosan coated poly lactic-co-glycolic acid (PLGA) nanoparticles conjugated with a novel anti-A? antibody. Measurements made according to Derjaguin-Landau-Verwey-Overbeek (DLVO) theory indicated that the immuno-nanovehicles have a much lower propensity to aggregate than the control nanovehicles. Immuno-nanovehicles showed enhanced uptake at the BBB and better targeting of the A? proteins deposited in the CAA model in vitro compared to the control nanovehicles. In addition, chitosan enhanced aqueous dispersibility and increased the stability of immuno-nanovehicles during lyophilization thus transforming them into ideal vehicles for delivering therapeutic/diagnostic agents to the cerebral vasculature ridden with vascular amyloid.

Jaruszewski, Kristen M.; Ramakrishnan, Subramanian; Poduslo, Joseph F.; Kandimalla, Karunya K.

2013-01-01

34

Hollow chitosan-silica nanospheres as pH-sensitive targeted delivery carriers in breast cancer therapy.  

PubMed

Promising drug nanocarriers consisting of mono-dispersed and pH sensitive chitosan-silica hollow nanospheres (CS-SiO(2) HNPs) suitable for breast cancer therapy are produced and investigated. The SiO(2) HNPs are fabricated using a one-step, one-medium process which obviates the need for post-treatment to remove the templates, additional dissolution, or calcination. Taking advantage of the cross-linking reaction with (3-Glycidyloxypropyl) trimethoxysilane (GTPMS), cationic polysaccharide-chitosan decorates the surface and produces pH sensitive CS-SiO(2) HNPs. The materials enable controlled release of loaded drugs in pericellular and interstitial environments. In particular, the antibody molecule (to ErbB 2) can be conjugated onto the surface of the CS-SiO(2) HNPs thereby allowing the hollow nanospheres to serve as a targeted delivery agent to breast cancer cells. TNF-? are delivered to MCF-7 breast cancer cells under both in vitro and in vivo conditions to suppress the growth of cancerous cells and even kill them with high therapeutic efficacy. Owing to their hollow inner cavity and porous structures, the CS-SiO(2) HNPs are excellent pH-responsive targeted nanocarriers. PMID:21486679

Deng, Ziwei; Zhen, Zipeng; Hu, Xiaoxi; Wu, Shuilin; Xu, Zushun; Chu, Paul K

2011-04-12

35

Effect of the stability and deformability of self-assembled glycol chitosan nanoparticles on tumor-targeting efficiency.  

PubMed

To evaluate the tumor targeting efficiency of self-assembled polymeric nanoparticles, four glycol chitosan nanoparticles (CNPs) with different degrees of hydrophobic substitution were prepared by coupling 7.5, 12, 23, and 35 wt.% of 5?-cholanic acid to hydrophilic glycol chitosan polymer (GC). The sizes and zeta-potentials of different CNPs in aqueous condition were not significantly different, but their stability and deformability were greatly dependent upon the degree of substitution (DS) of 5?-cholanic acid. With an increase in hydrophobicity, CNPs became more stable and rigid, as characterized by SDS-PAGE and filtration tests. To compare with CNPs, linear GC and polystyrene nanoparticles (PSNPs) were employed as controls. In vivo tumor accumulation of Cy5.5-labeled linear GC, polystyrene nanoparticles (PSNPs) and CNPs were monitored in flank tumors and liver tumor-bearing mice models using near-infrared fluorescence (NIRF) imaging systems. CNPs displayed higher tumor accumulation than GC and PSNPs via the enhanced permeability and retention (EPR) effect. Interestingly, CNPs containing 23 wt.% of 5?-cholanic acid (CNP-23%) showed the highest tumor-targeting efficiency compared to other CNPs. As exemplified in this study, the stability of CNP-23% is better than CNP-7.5% and CNP-12% containing 7.5 wt.% and 12 wt.% of 5?-cholanic acid, respectively, and the deformability of CNP-23% is better than that of CNP-35% containing 35 wt.% of 5?-cholanic acid. We proposed that the superior tumor-targeting efficiency of CNP-23% is mainly due to their balanced stability and deformability in vivo. This study demonstrates that the degree of hydrophobic substitution of self-assembled nanoparticles could determine their stability and deformability. Importantly, they were founded to be the key factors which affect their tumor-targeting efficiency in vivo, and so that these factors should be highly considered during developing nanoparticles for tumor-targeted imaging or drug delivery. PMID:22846988

Na, Jin Hee; Lee, Seung-Young; Lee, Sangmin; Koo, Heebeom; Min, Kyung Hyun; Jeong, Seo Young; Yuk, Soon Hong; Kim, Kwangmeyung; Kwon, Ick Chan

2012-07-27

36

Physicochemical, pharmaceutical and biological approaches toward designing optimized and efficient hydrophobically modified chitosan-based polymeric micelles as a nanocarrier system for targeted delivery of anticancer drugs.  

PubMed

Abstract Hydrophobically modified chitosan-based polymeric micelles (CBPMs) are formed through self-aggregation of chitosan amphiphilic derivatives. Their core-shell structure, diversity and the fact that all of their properties are adjustable through reconciling the interactions among their three main constituents: chitosan, hydrophilic segment and hydrophobic segment as well as with the outside medium through changing the ratio and chemical structure of each component's, chemical structure distinguish them from other chitosan-based drug delivery systems (DDSs) and give rise to these promising candidates for targeted delivery of lipophilic anticancer drugs. The majority of review articles conducted previously on chitosan-based DDSs have only made simple differential comparisons between such systems and the anticancer drugs that have been delivered through them. In this review article, all the basic properties of CBPMs including physicochemical, pharmaceutical and biological properties are technically detailed and discussed. The intention of this article is to outline and discuss salient features of CBPMs to contribute to the understanding of optimized strategies for the design of stable and efficient CBPMs. PMID:23915108

Mahmoudzadeh, Mohammad; Fassihi, Afshin; Emami, Jaber; Davies, Neal M; Dorkoosh, Farid

2013-08-05

37

Targeted delivery of insoluble cargo (paclitaxel) by PEGylated chitosan nanoparticles grafted with Arg-Gly-Asp (RGD).  

PubMed

Poor delivery of insoluble anticancer drugs has so far precluded their clinical application. In this study, we developed a tumor-targeting delivery system for insoluble drug (paclitaxel, PTX) by PEGylated O-carboxymethyl-chitosan (CMC) nanoparticles grafted with cyclic Arg-Gly-Asp (RGD) peptide. To improve the loading efficiency (LE), we combined O/W/O double emulsion method with temperature-programmed solidification technique and controlled PTX within the matrix network as in situ nanocrystallite form. Furthermore, these CMC nanoparticles were PEGylated, which could reduce recognition by the reticuloendothelial system (RES) and prolong the circulation time in blood. In addition, further graft of cyclic RGD peptide at the terminal of PEG chain endowed these nanoparticles with higher affinity to in vitro Lewis lung carcinoma (LLC) cells and in vivo tumor tissue. These outstanding properties enabled as-designed nanodevice to exhibit a greater tumor growth inhibition effect and much lower side effects over the commercial formulation Taxol. PMID:22559746

Lv, Pi-Ping; Ma, Yu-Feng; Yu, Rong; Yue, Hua; Ni, De-Zhi; Wei, Wei; Ma, Guang-Hui

2012-05-15

38

Preparation and characterization of biocompatible chitosan nanoparticles for targeted brain delivery of peptides.  

PubMed

Here, we describe a nanocarrier system that can transfer chitosan nanoparticles loaded with either small peptides such as the caspase inhibitor Z-DEVD-FMK or a large peptide like basic fibroblast growth factor across the blood-brain barrier. The nanoparticles are selectively directed to the brain and are not measurably taken up by liver and spleen. Intravital fluorescent microscopy provides an opportunity to study the penetration kinetics of nanoparticles loaded with fluorescent agents such as Nile red, and has demonstrated that this nanomedicine formulation is rapidly transported across the blood-brain barrier. PMID:22367822

Caban, Secil; Capan, Y?lmaz; Couvreur, Patrick; Dalkara, Turgay

2012-01-01

39

Superparamagnetic iron oxide nanoparticles-loaded chitosan-linoleic acid nanoparticles as an effective hepatocyte-targeted gene delivery system.  

PubMed

The goal of this study was to develop a gene delivery imaging system that targets hepatocytes to help diagnose and treat various liver diseases. To this end, we prepared superparamagnetic iron oxide nanoparticles (SPIO)-loaded with water-soluble chitosan (WSC)-linoleic acid (LA) nanoparticles (SCLNs) that formed gene complexes capable of localizing specifically to hepatocytes. We confirmed that (99m)Tc-labeled SCLNs delivered into mice via intravenous injection accumulated mainly in the liver using nuclear and magnetic resonance imaging. SCLN/enhanced green fluorescence protein (pEGFP) complexes were also successfully formed and were characterized with a gel retardation assay. SCLN/pEGFP complexes were transfected into primary hepatocytes, where GFP expression was observed in the cytoplasm. In addition, the injection of the gene complexes into mice resulted in significantly increased expression of GFP in hepatocytes in vivo. Furthermore, gene silencing was effectively achieved by administration of gene complexes loaded with specific siRNAs. In conclusion, our results indicate that the SCLNs have the potential to be useful for hepatocyte-targeted imaging and effective gene delivery into hepatocytes. PMID:19429277

Cheong, Su-Jin; Lee, Chang-Moon; Kim, Se-Lim; Jeong, Hwan-Jeong; Kim, Eun-Mi; Park, Eun-Hye; Kim, Dong Wook; Lim, Seok Tae; Sohn, Myung-Hee

2009-01-20

40

Low Molecular Weight Hydroxyethyl Chitosan-Prednisolone Conjugate for Renal Targeting Therapy: Synthesis, Characterization and In Vivo Studies  

PubMed Central

To further evaluate the potential renal targeting profile of low molecular weight hydroxyethyl chitosan (LMWHC) we developed before, prednisolone (Pre) was conjugated with LMWHC by EDC/NHS chemistry to improve the therapeutic effect of glucocorticoids in vivo. The conjugate was denoted as LMWHC-Pre. The prednisolone content of the conjugate was determined by reversed-phase high-performance liquid chromatography (HPLC) with Kromasil C18 column. The results showed that the average coupling degree of prednisolone to LMWHC was 76.7±3.2 ?g·mg-1. The stability and physicochemical characterization of LMWHC-Pre under various conditions were also investigated. To study the fate of LMWHC-Pre after intravenous (i.v.) administration, fluorescein isothiocyanate (FITC) was coupled to the conjugate to explore the renal targeting efficacy. The in vivo results showed that significant amount of the conjugate was accumulated into the kidneys while negligible signal could be detected when the mixture of FITC-LMWHC and prednisolone was co-administered. The preliminary pharmacodynamics study of LMWHC-Pre showed that the conjugate could effectively alleviate the nephrotic syndrome of rats induced by minimal change nephrosis (MCN) model. Toxicity study also revealed that there was little glucocorticoid-induced osteoporosis by LMWHC-Pre upon 20 days of treatment. From this study, LMWHC-Pre may be employed as an effective potential drug candidate for the treatment of chronic renal disease.

He, Xia-kai; Yuan, Zhi-xiang; Wu, Xiao-juan; Xu, Chao-qun; Li, Wan-yu

2012-01-01

41

Novel albendazole-chitosan nanoparticles for intestinal absorption enhancement and hepatic targeting improvement in rats.  

PubMed

To improve the treatment of helminthiasis, filariasis, and colorectal cancer, albendazole-associated chitosan nanoparticles (ABZ-CS-NPs) were prepared using the emulsion crosslinking volatile technique with contained sodium tripolyphosphate as the crosslinking agent and Poloxamer 188 as the auxiliary solvent. The structural characteristics of the NPs were determined using X-ray diffraction to analyze the interaction between CS and the drug. The NPs were then evaluated in terms of their physicochemical characteristics, drug release behavior, in vivo pharmacokinetic parameters, and biodistribution in animal studies. ABZ-loaded NPs with a uniformly spherical particle sizes (157.8 ± 2.82 nm) showed efficient drug loading, encapsulated efficiency, and high physical stability. The drug release from ABZ-CS-NPs was extended over several periods. Kinetic models were then fitted to determine the release mechanisms. ABZ and its metabolite albendazole sulfoxide (ABZSX) were analyzed in rats with mebendazole as the internal standard using reversed-phase high-performance liquid chromatography. Compared with the ABZ suspension groups, the relative bioavailability values of ABZ and ABZSX were 146.05 and 222.15%, respectively. In addition, the plasma concentration versus time curve is consistent with that of the two compartment models in the plasma concentration versus time curve. The results indicate that the ABZ-loaded NPs are promising novel ABZ candidates for passive diffusion in the treatment of hydatid cysts in the liver via oral administration. PMID:23529958

Liu, Yang; Wang, Xiao-qing; Ren, Wei-xin; Chen, Yuan-lan; Yu, Yang; Zhang, Jian-kang; Bawudong, Dilimulati; Gu, Jun-peng; Xu, Xiao-dong; Zhang, Xue-nong

2013-03-26

42

Development and evaluation of thymoquinone-encapsulated chitosan nanoparticles for nose-to-brain targeting: a pharmacoscintigraphic study  

PubMed Central

Chitosan (CS) nanoparticles of thymoquinone (TQ) were prepared by the ionic gelation method and are characterized on the basis of surface morphology, in vitro or ex vivo release, dynamic light scattering, and X-ray diffractometry (XRD) studies. Dynamic laser light scattering and transmission electron microscopy confirmed the particle diameter was between 150 to 200 nm. The results showed that the particle size of the formulation was significantly affected by the drug:CS ratio, whereas it was least significantly affected by the tripolyphosphate:CS ratio. The entrapment efficiency and loading capacity of TQ was found to be 63.3% ± 3.5% and 31.23% ± 3.14%, respectively. The drug-entrapment efficiency and drug-loading capacity of the nanoparticles appears to be inversely proportional to the drug:CS ratio. An XRD study proves that TQ dispersed in the nanoparticles changes its form from crystalline to amorphous. This was further confirmed by differential scanning calorimetry thermography. The flat thermogram of the nanoparticle data indicated that TQ formed a molecular dispersion within the nanoparticles. Optimized nanoparticles were evaluated further with the help of scintigraphy imaging, which ascertains the uptake of drug into the brain. Based on maximum concentration, time-to-maximum concentration, area-under-curve over 24 hours, and elimination rate constant, intranasal TQ-loaded nanoparticles (TQ-NP1) proved more effective in brain targeting compared to intravenous and intranasal TQ solution. The high drug-targeting potential and efficiency demonstrates the significant role of the mucoadhesive properties of TQ-NP1.

Alam, Sanjar; Khan, Zeenat I; Mustafa, Gulam; Kumar, Manish; Islam, Fakhrul; Bhatnagar, Aseem; Ahmad, Farhan J

2012-01-01

43

Enhanced Antitumor Activity of the Photosensitizer meso-Tetra(N-methyl-4-pyridyl) Porphine Tetra Tosylate through Encapsulation in Antibody-Targeted Chitosan/Alginate Nanoparticles  

PubMed Central

meso-Tetra(N-methyl-4-pyridyl) porphine tetra tosylate (TMP) is a photosensitizer that can be used in photodynamic therapy (PDT) to induce cell death through generation of reactive oxygen species in targeted tumor cells. However, TMP is highly hydrophilic, and therefore, its ability to accumulate intracellularly is limited. In this study, a strategy to improve TMP uptake into cells has been investigated by encapsulating the compound in a hydrogel-based chitosan/alginate nanoparticle formulation. Nanoparticles of 560 nm in diameter entrapping 9.1 ?g of TMP per mg of formulation were produced and examined in cell-based assays. These particles were endocytosed into human colorectal carcinoma HCT116 cells and elicited a more potent photocytotoxic effect than free drug. Antibodies targeting death receptor 5 (DR5), a cell surface apoptosis-inducing receptor up-regulated in various types of cancer and found on HCT116 cells, were then conjugated onto the particles. The conjugated antibodies further enhanced uptake and cytotoxic potency of the nanoparticle. Taken together, these results show that antibody-conjugated chitosan/alginate nanoparticles significantly enhanced the therapeutic effectiveness of entrapped TMP. This novel approach provides a strategy for providing targeted site-specific delivery of TMP and other photosensitizer drugs to treat colorectal tumors using PDT.

2013-01-01

44

Enhanced antitumor activity of the photosensitizer meso-Tetra(N-methyl-4-pyridyl) porphine tetra tosylate through encapsulation in antibody-targeted chitosan/alginate nanoparticles.  

PubMed

meso-Tetra(N-methyl-4-pyridyl) porphine tetra tosylate (TMP) is a photosensitizer that can be used in photodynamic therapy (PDT) to induce cell death through generation of reactive oxygen species in targeted tumor cells. However, TMP is highly hydrophilic, and therefore, its ability to accumulate intracellularly is limited. In this study, a strategy to improve TMP uptake into cells has been investigated by encapsulating the compound in a hydrogel-based chitosan/alginate nanoparticle formulation. Nanoparticles of 560 nm in diameter entrapping 9.1 ?g of TMP per mg of formulation were produced and examined in cell-based assays. These particles were endocytosed into human colorectal carcinoma HCT116 cells and elicited a more potent photocytotoxic effect than free drug. Antibodies targeting death receptor 5 (DR5), a cell surface apoptosis-inducing receptor up-regulated in various types of cancer and found on HCT116 cells, were then conjugated onto the particles. The conjugated antibodies further enhanced uptake and cytotoxic potency of the nanoparticle. Taken together, these results show that antibody-conjugated chitosan/alginate nanoparticles significantly enhanced the therapeutic effectiveness of entrapped TMP. This novel approach provides a strategy for providing targeted site-specific delivery of TMP and other photosensitizer drugs to treat colorectal tumors using PDT. PMID:23327610

Abdelghany, Sharif M; Schmid, Daniela; Deacon, Jill; Jaworski, Jakub; Fay, Francois; McLaughlin, Kirsty M; Gormley, Julie A; Burrows, James F; Longley, Daniel B; Donnelly, Ryan F; Scott, Christopher J

2013-01-31

45

Optimization of brain targeted chitosan nanoparticles of Rivastigmine for improved efficacy and safety.  

PubMed

The study aims at formulation and optimization brain targeted nanoparticles (NP) of Rivastigmine (RT) to improve its therapeutic potential and to verify its safety profile. The NP were optimized using a two factor three level (3(2)) central composite design aiming to minimize particle size; maximize zeta potential and drug entrapment efficiency of NP. The optimized formulation (cRTNP) was evaluated using in vitro drug release study; in vivo behavioral, and biochemical and maximum tolerated dose (MTD) study. The optimized formulation evidenced a significant reversal of scopolamine-induced amnesia by Tween 80(®) coated nanoparticles as compared to both pure RT as well as uncoated nanoparticles. The MTD of RT was increased by 10% by formulating them as cRTNP. Thus, formulation of RT as cRTNP improved the therapeutic and safety profile of RT. PMID:23597710

Nagpal, Kalpana; Singh, S K; Mishra, D N

2013-04-15

46

PEGylated chitosan-based polymer micelle as an intracellular delivery carrier for anti-tumor targeting therapy  

Microsoft Academic Search

Stearic acid-grafted chitosan oligosaccharide (CSO-SA) micelles presented a potential candidate for intracellular drug delivery carrier due to its special spatial structure. In this article, CSO-SA was further modified by polyethylene glycol (PEG). The physicochemical properties of PEGylated CSO-SA (PEG-CSO-SA) micelles were characterized. After PEGylation, the critical micelle concentration (CMC) of PEG-CSO-SA had no significant change; the micelle size increased; and

Fu-Qiang Hu; Pan Meng; You-Qin Dai; Yong-Zhong Du; Jian You; Xiao-Hong Wei; Hong Yuan

2008-01-01

47

Synthesis of TAT peptide-tagged PEGylated chitosan nanoparticles for siRNA delivery targeting neurodegenerative diseases.  

PubMed

Delivery of therapeutic molecules to the brain for the treatment of Neurodegenerative diseases (ND) is a challenging task. This manuscript introduces a novel scheme of synthesizing peptide-tagged polyethylene glycol (PEG)ylated chitosan polymer to develop nanoparticles for siRNA delivery for use in ND. Specifically, this manuscript proposes a facile chemoselective conjugation of monomethoxy PEG, at the C2 hydroxyl group of chitosan polymer, with conjugation of PEG to a cell-penetrating peptide, Trans-Activator of Transcription. The synthesized Chitosan-PEG-TAT polymer was used to form the nanoparticles of approximately 5 nm, complexing siRNA to be delivered in neuronal cells (Neuro 2a), with no/minimal toxicity. The various intermediates and the final product formed during the synthesis were characterized using (1)H Nuclear Magnetic Resonance and Fourier Transform Infrared Spectroscopy spectra. The morphological details of the nanoparticles were studied using Transmission Electron Microscopy. The nanoparticles were tested to deliver a functional siRNA against the Ataxin-1 gene in an in-vitro established model of a ND Spinocerebellar ataxia (SCA1) over-expressing ataxin protein. The results indicate successful suppression of the SCA1 protein following 48 h of transfection. Result of this study has potential in ND like SCA, Parkinson's, Alzheimer's and others. PMID:23140978

Malhotra, Meenakshi; Tomaro-Duchesneau, Catherine; Prakash, Satya

2012-11-08

48

Functional chitosan nanocarriers for potential applications in gene therapy  

Microsoft Academic Search

Functional chitosan nanocarriers for suicide gene therapy have been developed. Folic acid conjugated chitosan (FA-chitosan) was used to synthesize zinc sulphide quantum dots (ZnS QDs), which was further converted to chitosan nanocarriers, where the integrated FA acts as targeting, and the embedded QDs as imaging functionalities, respectively. The synthesized nanocarriers were almost spherical with sizes of ~75nm and were nontoxic

Amit Jaiswal; Arun Chattopadhyay; Siddhartha Sankar Ghosh

49

Galactosylated chitosan-g-PEI\\/DNA complexes-loaded poly(organophosphazene) hydrogel as a hepatocyte targeting gene delivery system  

Microsoft Academic Search

Hydrogels are widely used in drug delivery systems because they can control the release and thereby enhance the efficiency\\u000a of locally delivered bioactive molecules such as therapeutic drugs, proteins, or genes. For gene delivery, localized release\\u000a of plasmid DNA or polymer\\/DNA complexes can transfect cells and produce sustained protein production. We tested the galactosylated\\u000a chitosan-graft-polyethylenimine (GC-g-PEI)\\/DNA complexes-loaded poly(organophosphazene) thermosensitive biodegradable

Hu-Lin Jiang; You-Kyoung Kim; Sun-Mi Lee; Mi-Ran Park; Eun-Mi Kim; Yong-Mei Jin; Rohidas Arote; Hwan-Jeong Jeong; Soo-Chang Song; Myung-Haing Cho; Chong-Su Cho

2010-01-01

50

Synthesis and efficient hepatocyte targeting of galactosylated chitosan as a gene carrier in vitro and in vivo.  

PubMed

While chitosan (CS) has been researched widely as a non-viral vector, its usefulness has been limited by its low cell specificity and transfection efficiency. Therefore, we successfully synthesized galactosylated chitosan (GC) and complexed it with an enhanced green fluorescent protein plasmid (pIRES-EGFP) for transfection into cultured H22 cells (murine hepatic cancer cell line) using various GC/EGFP (N/P) charge ratios. Maximal gene transfection rates detected by flow cytometry occurred at an N/P ratio 5:1. Compared with those of lipofectin/EGFP and naked pIRES-EGFP, GC/EGFP complexes show a very efficient cell-selective transfection to hepatocytes. The MTT assay detected relatively low cytotoxicity in cells transfected with GC. A recombinant plasmid granulocyte-macrophage colony-stimulating factor (GM-SCF) and interleukin (IL) 21 (pIRES/GM-CSF-IL21) was successfully constructed and GC/GM-CSF-IL21 nanoparticles (average diameter, 82.1 nm) were administered via the tail vein of mice with liver metastasis of colon cancer model, for 5 consecutive days. The GC/GM-CSF-IL21 nanoparticles exhibited hepatocyte and passive tumor specificity, increased therapeutic efficacy compared to control groups, promoted leukocytes to aggregate in tumor tissues, and activated the cytotoxicity of natural killer (NK) cells and cytolytic T lymphocyte (CTL). Our results indicate that GC can be used in gene therapy to improve transfection efficiency and can be used as an immunological stimulant in vivo. PMID:21656667

Cheng, Mingrong; Li, Qing; Wan, Tao; Hong, Xiaowu; Chen, Houxiang; He, Bing; Cheng, Zhijian; Xu, Hongzhi; Ye, Tao; Zha, Bingbing; Wu, Jingbo; Zhou, Runjiao

2011-06-07

51

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.

Shrestha, Annie; Hamblin, Michael R.

2012-01-01

52

Galactosylated trimethyl chitosan-cysteine nanoparticles loaded with Map4k4 siRNA for targeting activated macrophages.  

PubMed

Galactosylated trimethyl chitosan-cysteine (GTC) nanoparticles (NPs) were developed for oral delivery of a mitogen-activated protein kinase kinase kinase kinase 4 (Map4k4) siRNA (siMap4k4) to the activated macrophages for treatment of dextran sulfate sodium (DSS)-induced ulcerative colitis (UC). siRNA loaded GTC NPs were prepared based on ionic gelation of GTC with anionic crosslinkers (tripolyphosphate (TPP) or hyaluronic acid (HA)). The types of crosslinkers involved in GTC NPs significantly affected their physicochemical characteristics. GTC/TPP NPs with smaller particle size and lower zeta potential possessed superior structural stability in gastrointestinal environment compared to GTC/HA NPs. Cellular uptake of GTC/TPP NPs in activated macrophages was significantly enhanced compared to trimethyl chitosan-cysteine (TC)/TPP NPs owing to galactose receptor-mediated endocytosis. The in vitro and in vivo gene knockdown measurement showed that siMap4k4 loaded GTC/TPP NPs effectively inhibited TNF-? production, which remarkably outperformed siMap4k4 loaded TC/TPP NPs. Compared to TC/TPP NPs, GTC/TPP NPs more efficiently promoted the distribution of siRNA in ulcerative colon following oral administration. Daily oral administration of GTC/TPP NPs containing siMap4k4 significantly improved DSS-induced body weight loss, colon length shortening, and increase of myeloperoxidase activity. This study would provide an effective approach for oral siRNA delivery in the treatment of inflammatory bowel diseases. PMID:23419643

Zhang, Jing; Tang, Cui; Yin, Chunhua

2013-02-15

53

Formulation Development and Evaluation of Drug Release Kinetics from Colon-Targeted Ibuprofen Tablets Based on Eudragit RL 100-Chitosan Interpolyelectrolyte Complexes  

PubMed Central

Colon-targeted drug delivery systems (CTDDSs) could be useful for local treatment of inflammatory bowel diseases (IBDs). In this study, various interpolyelectrolyte complexes (IPECs), formed between Eudragit RL100 (EL) and chitosan (CS), by nonstoichiometric method, and tablets based on the IPECs, prepared by wet granulation, were evaluated as potential oral CTDDSs for ibuprofen (IBF). Results obtained showed that the tablets conformed to compendial requirements for acceptance and that CS and EL formed IPECs that showed pH-dependent swelling properties and prolonged the in vitro release of IBF from the tablets in the following descending order: 3?:?2?>?2?:?3?>?1?:?1 ratios of CS and EL. An electrostatic interaction between the carbonyl (–CO–) group of EL and amino (–NH3+) group of CS of the tablets formulated with the IPECs was capable of preventing drug release in the stomach and small intestine and helped in delivering the drug to the colon. Kinetic analysis of drug release profiles showed that the systems predominantly released IBF in a zero-order manner. IPECs based on CS and EL could be exploited successfully for colon-targeted delivery of IBF in the treatment of IBDs.

Ofokansi, Kenneth Chibuzor; Kenechukwu, Franklin Chimaobi

2013-01-01

54

Formulation Development and Evaluation of Drug Release Kinetics from Colon-Targeted Ibuprofen Tablets Based on Eudragit RL 100-Chitosan Interpolyelectrolyte Complexes.  

PubMed

Colon-targeted drug delivery systems (CTDDSs) could be useful for local treatment of inflammatory bowel diseases (IBDs). In this study, various interpolyelectrolyte complexes (IPECs), formed between Eudragit RL100 (EL) and chitosan (CS), by nonstoichiometric method, and tablets based on the IPECs, prepared by wet granulation, were evaluated as potential oral CTDDSs for ibuprofen (IBF). Results obtained showed that the tablets conformed to compendial requirements for acceptance and that CS and EL formed IPECs that showed pH-dependent swelling properties and prolonged the in vitro release of IBF from the tablets in the following descending order: 3?:?2?>?2?:?3?>?1?:?1 ratios of CS and EL. An electrostatic interaction between the carbonyl (-CO-) group of EL and amino (-NH3 (+)) group of CS of the tablets formulated with the IPECs was capable of preventing drug release in the stomach and small intestine and helped in delivering the drug to the colon. Kinetic analysis of drug release profiles showed that the systems predominantly released IBF in a zero-order manner. IPECs based on CS and EL could be exploited successfully for colon-targeted delivery of IBF in the treatment of IBDs. PMID:23986877

Ofokansi, Kenneth Chibuzor; Kenechukwu, Franklin Chimaobi

2013-08-06

55

Process optimization for the preparation of oligomycin-loaded folate-conjugated chitosan nanoparticles as a tumor-targeted drug delivery system using a two-level factorial design method  

PubMed Central

Oligomycin-A (Oli-A), an anticancer drug, was loaded to the folate (FA)-conjugated chitosan as a tumor-targeted drug delivery system for the purpose of overcoming the nonspecific targeting characteristics and the hydrophobicity of the compound. The two-level factorial design (2-LFD) was applied to modeling the preparation process, which was composed of five independent variables, namely FA-conjugated chitosan (FA-CS) concentration, Oli-A concentration, sodium tripolyphosphate (TPP) concentration, the mass ratio of FA-CS to TPP, and crosslinking time. The mean particle size (MPS) and the drug loading rate (DLR) of the resulting Oli-loaded FA-CS nanoparticles (FA-Oli-CSNPs) were used as response variables. The interactive effects of the five independent variables on the response variables were studied. The characteristics of the nanoparticles, such as amount of FA conjugation, drug entrapment rate (DER), DLR, surface morphology, and release kinetics properties in vitro were investigated. The FA-Oli-CSNPs with MPS of 182.6 nm, DER of 17.3%, DLR of 58.5%, and zeta potential (ZP) of 24.6 mV were obtained under optimum conditions. The amount of FA conjugation was 45.9 mg/g chitosan. The FA-Oli-CSNPs showed sustained-release characteristics for 576 hours in vitro. The results indicated that FA-Oli-CSNPs obtained as a targeted drug delivery system could be effective in the therapy of leukemia in the future.

Zu, Yuangang; Zhao, Qi; Zhao, Xiuhua; Zu, Shuchong; Meng, Li

2011-01-01

56

Process optimization for the preparation of oligomycin-loaded folate-conjugated chitosan nanoparticles as a tumor-targeted drug delivery system using a two-level factorial design method.  

PubMed

Oligomycin-A (Oli-A), an anticancer drug, was loaded to the folate (FA)-conjugated chitosan as a tumor-targeted drug delivery system for the purpose of overcoming the nonspecific targeting characteristics and the hydrophobicity of the compound. The two-level factorial design (2-LFD) was applied to modeling the preparation process, which was composed of five independent variables, namely FA-conjugated chitosan (FA-CS) concentration, Oli-A concentration, sodium tripolyphosphate (TPP) concentration, the mass ratio of FA-CS to TPP, and crosslinking time. The mean particle size (MPS) and the drug loading rate (DLR) of the resulting Oli-loaded FA-CS nanoparticles (FA-Oli-CSNPs) were used as response variables. The interactive effects of the five independent variables on the response variables were studied. The characteristics of the nanoparticles, such as amount of FA conjugation, drug entrapment rate (DER), DLR, surface morphology, and release kinetics properties in vitro were investigated. The FA-Oli-CSNPs with MPS of 182.6 nm, DER of 17.3%, DLR of 58.5%, and zeta potential (ZP) of 24.6 mV were obtained under optimum conditions. The amount of FA conjugation was 45.9 mg/g chitosan. The FA-Oli-CSNPs showed sustained-release characteristics for 576 hours in vitro. The results indicated that FA-Oli-CSNPs obtained as a targeted drug delivery system could be effective in the therapy of leukemia in the future. PMID:22267927

Zu, Yuangang; Zhao, Qi; Zhao, Xiuhua; Zu, Shuchong; Meng, Li

2011-12-20

57

Preparation of gadopentetic acid-loaded chitosan microparticles for gadolinium neutron-capture therapy of cancer by a novel emulsion-droplet coalescence technique.  

PubMed

Biodegradable gadopentetic acid (Gd-DTPA)-loaded chitosan microparticles (Gd-microCPs) were prepared as a device for gadolinium neutron-capture therapy (Gd-NCT) by a novel emulsion-droplet coalescence technique: a water-in-oil (w/o) emulsion A containing chitosan and Gd-DTPA in droplets and a w/o emulsion B containing NaOH in droplets were mixed and stirred to solidify chitosan as a result of collision and coalescence between droplets of each emulsion. Gd-microCPs prepared by using 100% deacetylated chitosan in 25% Gd-DTPA solution were 4.1 microns (non-lyophilized) and 3.3 microns (lyophilized) in mass median diameter, and were 3.4% in gadolinium content, corresponding to 11.7% as Gd-DTPA. The particle size and gadolinium content of Gd-microCPs were not affected by Gd-DTPA concentration in the chitosan medium. However, the deacetylation degree of chitosan influenced the particle size; as the deacetylation degree of chitosan decreased, the particle size increased. The incorporated Gd-DTPA was not released entirely from Gd-microCPs in an isotonic phosphate buffered saline solution despite the high water-solubility of Gd-DTPA (less than 0.8% with every type of Gd-microCPs). These results indicated that ion-complex formation might be contributable to incorporation of Gd-DTPA. As a preliminary study, it was confirmed that the loss of gamma-ray emission by gadolinium-loading in microparticle was negligible in the thermal neutron irradiation test in vitro. These results suggested that Gd-microCPs could be a useful device for intratumoral injection into solid tumor on Gd-NCT. PMID:10399838

Tokumitsu, H; Ichikawa, H; Fukumori, Y; Block, L H

1999-06-01

58

Folate-mediated targeted and intracellular delivery of paclitaxel using a novel deoxycholic acid-O-carboxymethylated chitosan-folic acid micelles  

PubMed Central

Background A critical disadvantage for successful chemotherapy with paclitaxel (PTX) is its nontargeting nature to cancer cells. Folic acid has been employed as a targeting ligand of various anticancer agents to increase their cellular uptake within target cells since the folate receptor is overexpressed on the surface of such tumor cells. In this study, a novel biodegradable deoxycholic acid-O-carboxymethylated chitosan–folic acid conjugate (DOMC-FA) was used to form micelles for encapsulating the anticancer drug PTX. Methods and results The drug-loading efficiency, encapsulation efficiency, in vitro drug release and physicochemical properties of PTX-loaded micelles were investigated in detail. In vitro cell culture studies were carried out in MCF-7 cells, a human breast carcinoma cell line, with folate receptor overexpressed on its surface. An increased level of uptake of folate-conjugated micelles compared to plain micelles in MCF-7 cells was observed, and the enhanced uptake of folate-micelles mainly on account of the effective process of folate receptor-mediated endocytosis. The MTT assay, morphological changes, and apoptosis test implied that the folate-conjugated micelles enhanced the cell death by folate-mediated active internalization, and the cytotoxicity of the FA-micellar PTX (DOMC-FA/PTX) to cancer cells was much higher than micelles without folate (DOMC/PTX) or the commercially available injectable preparation of PTX (Taxol). Conclusion Results indicate that the PTX-loaded DOMC-FA micelle is a successful anticancertargeted drug-delivery system for effective cancer chemotherapy.

Wang, Feihu; Chen, Yuxuan; Zhang, Dianrui; Zhang, Qiang; Zheng, Dandan; Hao, Leilei; Liu, Yue; Duan, Cunxian; Jia, Lejiao; Liu, Guangpu

2012-01-01

59

Synthesis and characterization of lactobionic acid grafted pegylated chitosan and nanoparticle complex application  

Microsoft Academic Search

A series of chemical modifications of chitosan were conducted by grafting a hydrophilic methoxy poly(ethylene glycol) (MPEG) and a target sugar molecule lactobionic acid (LA). The MPEG was grafted onto C6–OH position of chitosan, and the grafting degree was reduced for chitosan with high degree of depolymerization. The lactobionic acid was proposed to graft onto C2–NH2 position of chitosan. The

Wen Jen Lin; Tze Dan Chen; Chia-Wen Liu

2009-01-01

60

Novel biotinylated chitosan-graft-polyethyleneimine copolymer as a targeted non-viral vector for anti-EGF receptor siRNA delivery in cancer cells.  

PubMed

The major impediments to develop an efficient non-viral siRNA-mediated gene silencing method, as a therapeutic approach, are the low cellular uptake and intracellular delivery and release of non-viral vectors. To overcome these problems, designing a proper vector with high transfection efficiency is obviously under scrutiny of various studies. The present study, evaluate a novel biotinylated chitosan-graft-polyethyleneimine (Bio-Chi-g-PEI) copolymer as an appropriate non-viral vector for targeted delivery of siRNA to cancer cells. The composition of the synthesized Bio-Chi-g-PEI copolymer was thoroughly characterized using (1)H NMR and FTIR spectroscopy, besides the hydroxyazobenzene-2-carboxylic acid (HABA) assay. In vitro cytotoxicity assay of the Bio-Chi-g-PEI copolymers was performed by MTT assay. Cytotoxicity evaluations indicated that the new copolymer was markedly less toxic than PEI 25KD. Physicochemical properties of the Bio-Chi-g-PEI/siRNA complexes such as complex stability, size, zeta potential, and their morphology at various weight ratios, investigated by appropriate methods, revealed the suitability of the complexes for the transfection. The efficient cellular internalization of the complexes for HeLa and OVCAR-3 cells in culture media was confirmed by intracellular tracking of the prepared complexes using confocal laser scanning microscopy and Cy3-labeled anti-epidermal growth factor receptor siRNA. Finally, evaluation of the transfection efficiency and gene silencing by flow cytometry and real-time polymerase chain reaction highlighted the significantly higher efficiency of transfection and silencing for biotinylated copolymer compared with the PEI 25KD and non-biotinylated copolymer. PMID:24012865

Darvishi, Mohammad H; Nomani, Alireza; Amini, Mohsen; Shokrgozar, Mohammad A; Dinarvand, Rassoul

2013-09-03

61

Antibacterial action of chitosan  

Microsoft Academic Search

The antibacterial action of chitosan hydroglutamate (CH), chitosan lactate (CL) and chitosan derived from fungal mycelia was examined against both gram?negative and gram?positive bacteria. Plate counts indicated inactivation rates of one? to five?log?cycles within one hour. Fungal chitosan had significantly less antibiotic effect than CH and CL. The antibacterial action of CH and CL was very similar and shown to

N. R. Sudarshan; D. G. Hoover; D. Knorr

1992-01-01

62

Chitosan and radiation chemistry  

NASA Astrophysics Data System (ADS)

Chitosan as a raw material with special properties has drawn attention of scientists working in the field of radiation processing and natural polymer products development, and also of specialists working in the field of radiation protection and oncologists. Especially the applications concern reduced molecular weight chitosan which still retain its chemical structure; such form of the compound is fostering biological, physical and chemical reactivity of the product. Chitosan degrades into fragments under ?-ray or electron beam irradiation. Antibacterial properties of the product are applied in manufacturing hydrogel for wound dressing and additional healing properties can be achieved by incorporating in the hydrogel matrix chitosan bonded silver clusters. Another possible application of chitosan is in reducing radiation damage to the radiation workers or radiation cured patients. In the case of radioisotopes oral or respiratory chitosan-based materials can be applied as chelators. Applications of chitosan in oncology are also reported.

Chmielewski, Andrzej G.

2010-03-01

63

Design of deformable chitosan microspheres loaded with superparamagnetic iron oxide nanoparticles for embolotherapy detectable by magnetic resonance imaging.  

PubMed

The purpose of this study was to design chitosan microspheres (MS) loaded with superparamagnetic iron oxide nanoparticles (SPIO) suitable for anti-cancer embolotherapy detectable by MRI. Deformable chitosan MS loaded with varying SPIO concentrations (SPIO-chitosan MS) were prepared by ionotropic gelation and a porogenic technique using polyethylene glycol, followed by genipin crosslinking. Adding SPIO nanoparticles to chitosan MS did not significantly affect the chitosan MS morphology. An in vitro phantom study led to selecting SPIO-chitosan MS prepared with 1.0 mM SPIO for an in vivo MR traceability study. SPIO-chitosan MS could be identified following embolization in the renal artery by MRI at 18 weeks. Histological and pathological evidence also showed that SPIO-chitosan MS blocked and remained in the target vessels. Therefore, deformable SPIO-chitosan MS is MR-detectable embolic material with a possible application for anti-cancer embolotherapy. PMID:22944439

Chung, Eun-Young; Kim, Hyeong-Min; Lee, Ga-Hyeon; Kwak, Byung-Kook; Jung, Ji-Sung; Kuh, Hyo-Jeong; Lee, Jaehwi

2012-07-31

64

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.

Mitra, Analava; Dey, Baishakhi

2011-01-01

65

A self-organized 3-diethylaminopropyl-bearing glycol chitosan nanogel for tumor acidic pH targeting: In vitro evaluation  

Microsoft Academic Search

In this study, a novel pH-responsive nanogel composed of glycol chitosan (GCS) grafted with functional 3-diethylaminopropyl (DEAP) groups (denoted as GCS-g-DEAP hereafter) was fabricated. The GCS-g-DEAP was designed to have a self-assembled arrangement consisting of hydrophilic block (GCS) and hydrophobic block (DEAP) at physiological pH. As the pH decreased to tumor extracellular pH (pHe), the nanogel was destabilized due to

Nam Muk Oh; Kyung Taek Oh; Hye Jung Baik; Bo Reum Lee; A. Hyeong Lee; Yu Seok Youn; Eun Seong Lee

2010-01-01

66

Chitosan against cutaneous pathogens  

PubMed Central

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.

2013-01-01

67

Single crystals of chitosan.  

PubMed

Lamellar single crystals of chitosan were prepared at 125 degrees C by adding ammonia to a low DP fraction of chitosan dissolved in water. The crystals gave sharp electron diffraction diagrams which could be indexed in an orthorhombic P2(1)2(1)2(1) unit cell with a = 8.07 A, b = 8.44 A, c = 10.34 A. The unit cell contained two anti-parallel chitosan chains and no water molecules. It was found that cellulose microfibrils from Valonia ventricosa could act as nuclei for inducing the crystallization of chitosan on cellulose. This produced a shish-kebab morphology. PMID:2085494

Cartier, N; Domard, A; Chanzy, H

1990-10-01

68

Pharmaceutical applications of chitosan  

Microsoft Academic Search

Considerable research efforts have been directed towards the development of safe and efficient chitosan-based drug delivery systems. In this review, the authors outline the major new approaches to the pharmaceutical applications of chitosan and discuss its mechanisms of action in various in vitro and in vivo models.

Valérie Dodane; Vinod D Vilivalam

1998-01-01

69

Somatostatin receptor-mediated tumor-targeting drug delivery using octreotide-PEG-deoxycholic acid conjugate-modified N-deoxycholic acid-O, N-hydroxyethylation chitosan micelles.  

PubMed

In this study, a ligand-PEG-lipid conjugate, octreotide-polyethene glycol-deoxycholic acid (OCT(Phe)-PEG-DOCA, or OPD) was successfully synthesized and used as a targeting molecule for N-deoxycholic acid-O, N-hydroxyethylation chitosan (DAHC) micelles for efficient cancer therapy. DAHC micelles exhibited good loading capacities for doxorubicin (DOX), a model anti-cancer drug, and the modification of OPD showed no significant effect on drug load while slightly increasing the particle size and partly shielding the positive charges on the surface of micelles. Accelerated release rate of DOX from micelles were also observed after OPD modification and the release profile exhibited pH-sensitive properties. Compared with DAHC-DOX micelles, OPD-DAHC-DOX micelles exhibited significantly stronger cytotoxicity to MCF-7 cells (SSTRs overexpression) but with hardly any difference from WI-38 cells (no SSTRs expression). The results of flow cytometry and confocal laser scanning microscopy further revealed that OPD-DAHC-DOX micelles could be selectively taken into tumor cells by SSTRs-mediated endocytosis. In vivo investigation of micelles on nude mice bearing MCF-7 cancer xenografts confirmed that OPD-DAHC micelles possessed much higher tumor-targeting capacity than the DAHC control and exhibited enhanced anti-tumor efficacy and decreased systemic toxicity. These results suggest that OPD-DAHC micelles might be a promising anti-cancer drug delivery carrier for targeted cancer therapy. PMID:22704599

Huo, Meirong; Zou, Aifeng; Yao, Chengli; Zhang, Yong; Zhou, Jianping; Wang, Jing; Zhu, Qinnv; Li, Jing; Zhang, Qiang

2012-06-14

70

A self-organized 3-diethylaminopropyl-bearing glycol chitosan nanogel for tumor acidic pH targeting: in vitro evaluation.  

PubMed

In this study, a novel pH-responsive nanogel composed of glycol chitosan (GCS) grafted with functional 3-diethylaminopropyl (DEAP) groups (denoted as GCS-g-DEAP hereafter) was fabricated. The GCS-g-DEAP was designed to have a self-assembled arrangement consisting of hydrophilic block (GCS) and hydrophobic block (DEAP) at physiological pH. As the pH decreased to tumor extracellular pH (pH(e)), the nanogel was destabilized due to the protonation of DEAP. The pH-responsive property of the nanogel at tumor extracellular pH (pH(e)) was characterized in drug-release kinetic studies. The release of doxorubicin (DOX) from DOX-loaded nanogels was significantly accelerated at lower pH values, which allowed for increased DOX uptake by non-small lung carcinoma A546 cells under a slightly acidic pH condition, as in tumor pH(e). PMID:20299192

Oh, Nam Muk; Oh, Kyung Taek; Baik, Hye Jung; Lee, Bo Reum; Lee, A Hyeong; Youn, Yu Seok; Lee, Eun Seong

2010-02-26

71

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

2012-10-12

72

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

2013-10-02

73

Chitosan in Plant Protection  

PubMed Central

Chitin and chitosan are naturally-occurring compounds that have potential in agriculture with regard to controlling plant diseases. These molecules were shown to display toxicity and inhibit fungal growth and development. They were reported to be active against viruses, bacteria and other pests. Fragments from chitin and chitosan are known to have eliciting activities leading to a variety of defense responses in host plants in response to microbial infections, including the accumulation of phytoalexins, pathogen-related (PR) proteins and proteinase inhibitors, lignin synthesis, and callose formation. Based on these and other proprieties that help strengthen host plant defenses, interest has been growing in using them in agricultural systems to reduce the negative impact of diseases on yield and quality of crops. This review recapitulates the properties and uses of chitin, chitosan, and their derivatives, and will focus on their applications and mechanisms of action during plant-pathogen interactions.

El Hadrami, Abdelbasset; Adam, Lorne R.; El Hadrami, Ismail; Daayf, Fouad

2010-01-01

74

Chitosan in plant protection.  

PubMed

Chitin and chitosan are naturally-occurring compounds that have potential in agriculture with regard to controlling plant diseases. These molecules were shown to display toxicity and inhibit fungal growth and development. They were reported to be active against viruses, bacteria and other pests. Fragments from chitin and chitosan are known to have eliciting activities leading to a variety of defense responses in host plants in response to microbial infections, including the accumulation of phytoalexins, pathogen-related (PR) proteins and proteinase inhibitors, lignin synthesis, and callose formation. Based on these and other proprieties that help strengthen host plant defenses, interest has been growing in using them in agricultural systems to reduce the negative impact of diseases on yield and quality of crops. This review recapitulates the properties and uses of chitin, chitosan, and their derivatives, and will focus on their applications and mechanisms of action during plant-pathogen interactions. PMID:20479963

El Hadrami, Abdelbasset; Adam, Lorne R; El Hadrami, Ismail; Daayf, Fouad

2010-03-30

75

Influence of cross-linking agent type and chitosan content on the performance of pectinate-chitosan beads aimed for colon-specific drug delivery.  

PubMed

Pectinate-chitosan-beads aimed for colon theophylline delivery have been developed. The effect of zinc or calcium ions as cross-linking agent, and of chitosan concentration on the properties and colon-targeting performance of beads was investigated. Beads were characterized for morphology, entrapment efficiency and mucoadhesion properties. Zn-pectinate-chitosan beads formed a stronger gel network than the Ca-containing ones, enabling a greater entrapment efficiency, which further increased with chitosan content, probably due to polyelectrolyte complexes formation. Transport studies across Caco-2 cells evidenced a significant (p > 0.05) drug permeation increase from all beads with respect to drug alone, attributable to the enhancer and/or mucoadhesion properties of the polymers, and Ca-pectinate-chitosan beads were more effective than the Zn-containing ones. Beads formulated as enteric-coated tablets demonstrated good colon-targeting properties, and no differences were observed in drug-release profiles from Zn- or Ca-pectinate-chitosan beads. Therefore, Ca-pectinate-chitosan beads emerged as the choice formulation, joining colon-targeting specificity with better permeation enhancer power. PMID:22191551

Maestrelli, F; Cirri, M; Mennini, N; Bragagni, M; Zerrouk, N; Mura, P

2011-12-23

76

Investigation of Chitosan for Sorption of Radionuclides.  

National Technical Information Service (NTIS)

Chitosan is a biopolymer resulting from the deacetylation of chitin, the second most abundant biopolymer in nature. Chitosan has been successfully used in systems to remove metal ions and other pollutants from wastewater. Chitosan has shown promise as a s...

V. E. Holfeltz

2012-01-01

77

Antimicrobial action of exogenous chitosan.  

PubMed

The objective of this chapter is to present fundamental factors (e.g. intrinsic and extrinsic) influencing chitosan as antimicrobial agent, for effective practical application. The antimicrobial activity of chitosan is well observed on a wide variety of micro-organisms including fungi, algae and some bacteria. However, the antimicrobial action is influenced by intrinsic and extrinsic factors such as the type of chitosan (e.g. plain or derivative); degree of chitosan polymerization; host natural nutrient constituency; substrate chemical and/or nutrient composition; and environmental conditions (e.g. substrate water activity (Aw) and/or moisture). Although both plain and derivative chitosans are effective as antimicrobial agents, there is a differential effect between them. Their differential antimicrobial effect is mainly exhibited in live host plants; thus the antifungal effect of N-carboxymethyl chitosan (NCMC) is different in vegetable as compared with graminea host. At the same time, pentamer and heptamer chitosan units seem to have better antifungal action than larger units. Chitosan antimicrobial action is more immediate on fungi and algae, followed by bacteria; the chitosan site of action is at the microbial cell wall. PMID:10906970

Cuero, R G

1999-01-01

78

Chitin and chitosan from Basidiomycetes.  

PubMed

Chitinous material was isolated from the mycelium of seven species of Basidiomycetes to evaluate the possibility of using fungal biomass as a source of chitin and chitosan. Such material was characterised for its purity, degree of acetylation and crystallinity. Chitin yields ranged between 8.5 and 19.6% dry weight and the chitosan yield was approximately 1%. The characteristics of the fungal chitins were similar to those of commercial chitin. Chitosans, with a low degree of acetylation, comparable with that of commercial chitosan, were obtained by the chemical deacetylation of fungal chitins. PMID:18023863

Di Mario, F; Rapanà, P; Tomati, U; Galli, E

2007-10-09

79

Insights into the Mode of Action of Chitosan as an Antibacterial Compound? †  

PubMed Central

Chitosan is a polysaccharide biopolymer that combines a unique set of versatile physicochemical and biological characteristics which allow for a wide range of applications. Although its antimicrobial activity is well documented, its mode of action has hitherto remained only vaguely defined. In this work we investigated the antimicrobial mode of action of chitosan using a combination of approaches, including in vitro assays, killing kinetics, cellular leakage measurements, membrane potential estimations, and electron microscopy, in addition to transcriptional response analysis. Chitosan, whose antimicrobial activity was influenced by several factors, exhibited a dose-dependent growth-inhibitory effect. A simultaneous permeabilization of the cell membrane to small cellular components, coupled to a significant membrane depolarization, was detected. A concomitant interference with cell wall biosynthesis was not observed. Chitosan treatment of Staphylococcus simulans 22 cells did not give rise to cell wall lysis; the cell membrane also remained intact. Analysis of transcriptional response data revealed that chitosan treatment leads to multiple changes in the expression profiles of Staphylococcus aureus SG511 genes involved in the regulation of stress and autolysis, as well as genes associated with energy metabolism. Finally, a possible mechanism for chitosan's activity is postulated. Although we contend that there might not be a single classical target that would explain chitosan's antimicrobial action, we speculate that binding of chitosan to teichoic acids, coupled with a potential extraction of membrane lipids (predominantly lipoteichoic acid) results in a sequence of events, ultimately leading to bacterial death.

Raafat, Dina; von Bargen, Kristine; Haas, Albert; Sahl, Hans-Georg

2008-01-01

80

Preparation and antibacterial activity of chitosan nanoparticles  

Microsoft Academic Search

Chitosan nanoparticles, such as those prepared in this study, may exhibit potential antibacterial activity as their unique character. The purpose of this study was to evaluate the in vitro antibacterial activity of chitosan nanoparticles and copper-loaded nanoparticles against various microorganisms. Chitosan nanoparticles were prepared based on the ionic gelation of chitosan with tripolyphosphate anions. Copper ions were adsorbed onto the

Lifeng Qi; Zirong Xu; Xia Jiang; Caihong Hu; Xiangfei Zou

2004-01-01

81

Synthesis of Chitosan-Alginate Microcapsule Membranes  

Microsoft Academic Search

A polysaccharide, chitosan, was chemically modified to form a polyelectrolyte complex membrane with calcium alginate beads. A key factor in membrane for mation was found to be the viscosity average molecular weight (M v) of the chitosan. While unmodified chitosan (Mv = 12.1 x 105) formed thin and weak microcapsule membranes, when the Mv of the chitosan was reduced to

C. A. Mcknight; A. Ku; M. F. A. Goosen; D. Sun; C. Penney

1988-01-01

82

Development of lauroyl sulfated chitosan for enhancing hemocompatibility of chitosan  

Microsoft Academic Search

Chitosan (CS) has received much attention as a functional biopolymer especially in pharmaceutical applications, but has serious limitations owing to its poor hemo-compatibility property. Present paper focuses on the chemical modification of CS in order to enhance hemocompatibility. Amphiphilic derivative (lauroyl sulfated chitosan, LSCS) was prepared by the inclusion of sulfo group (hydrophilic) and lauroyl group (hydrophobic) to CS backbone

R. Shelma; Chandra P. Sharma

2011-01-01

83

Applications and Properties of Chitosan  

Microsoft Academic Search

Chitosan, a polycationic polymer and waste product from the sea food processing industry, is an abundant natural resource that has, as yet, not been fully utilized. Advantages of this polymer include availability, low cost, high biocompatibility, biodegradability and ease of chemical modification. In this paper, the physicochemical properties of chitosan, as well as its numerous applications, are reviewed with particular

Q. Li; E. T. Dunn; E. W. Grandmaison; M. F. A. Goosen

1992-01-01

84

Electrospun chitosan/PEDOT nanofibers.  

PubMed

Plasma-modified chitosan and poly(3,4-ethylenedioxythiophene) were blended to obtain conducting nanofibers with polyvinyl alcohol as a supporting polymer at various volumetric ratios by electrospinning method. Chemical compositions and molecular interactions among nanofiber blend components were determined using Fourier transform infrared spectroscopy (FTIR). The conducting blends containing plasma-modified chitosan resulted in a superior antibacterial activity and thinner fiber formation than those containing chitosan without plasma-modification. The obtained nanofiber diameters of plasma-modified chitosan were in the range of 170 to 200 nm and those obtained from unmodified chitosan were in the range of 190 to 246 nm. The electrical and electrochemical properties of nanofibers were also investigated by four-point probe conductivity and cyclic voltammetry measurements. PMID:23910286

Kiristi, Melek; Oksuz, Aysegul Uygun; Oksuz, Lutfi; Ulusoy, Seyhan

2013-05-16

85

Chitosan films are NOT antimicrobial.  

PubMed

Chitosan is a promising biomaterial for biomedical applications and is currently applied as wound dressings. While chitosan solutions demonstrate strong bactericidal activity against a range of medically important bacteria, the study here reports a loss of this beneficial property in thin films cast from the same solutions. Chitosan films (20 microm) showed no inhibitory effects against Escherichia coli, Staphylococcus aureus or S. epidermidis species. In contrast, solutions used to prepare the films showed almost complete inhibition (approximately 98 ± 2%) when tested on bacterial lawns and in liquid cultures. Increased acidity of the chitosan solutions (pH 5) was shown to promote the bactericidal effects of this biopolymer. The concept that devices fabricated from chitosan have an inherent antimicrobial activity is suggested as an important misconception. PMID:20953663

Foster, L John R; Butt, Julian

2010-10-16

86

Magnetic and fluorescent multifunctional chitosan nanoparticles as a smart drug delivery system  

Microsoft Academic Search

An innovative drug delivery system based on magnetic and fluorescent multifunctional chitosan nanoparticles was developed, which combined magnetic targeting, fluorescent imaging and stimulus-responsive drug release properties into one drug delivery system. Water-soluble superparamagnetic Fe3O4 nanoparticles, CdTe quantum dots (QDs) and pharmaceutical drugs were simultaneously incorporated into chitosan nanoparticles; cross-linking the composite particles with glutaraldehyde tailored their size, morphology, surface properties

Linlin Li; Dong Chen; Yanqi Zhang; Zhengtao Deng; Xiangling Ren; Xianwei Meng; Fangqiong Tang; Jun Ren; Lin Zhang

2007-01-01

87

Gadolinium loaded plastic scintillators for high efficiency neutron detection  

Microsoft Academic Search

Gadolinium has the highest thermal neutron absorption cross section of any naturally occurring element, and emits conversion electrons as well as atomic X-rays in over 50% of its neutron captures, which makes it a useful dopant in scintillators for detecting thermal neutrons. Gadolinium isopropoxide was studied as a possible dopant for styrene-based plastic scintillators as a convenient and inexpensive method

Lena Ovechkina; Kent Riley; Stuart Miller; Zane Bell; Vivek Nagarkar

2009-01-01

88

Antibacterial activity of chitosans and chitosan oligomers with different molecular weights  

Microsoft Academic Search

Antibacterial activities of six chitosans and six chitosan oligomers with different molecular weights (Mws) were examined against four gram-negative (Escherichia coli, Pseudomonas fluorescens, Salmonella typhimurium, and Vibrio parahaemolyticus) and seven gram-positive bacteria (Listeria monocytogenes, Bacillus megaterium, B. cereus, Staphylococcus aureus, Lactobacillus plantarum, L. brevis, and L. bulgaricus). Chitosans showed higher antibacterial activities than chitosan oligomers and markedly inhibited growth of

Hong Kyoon No; Na Young Park; Shin Ho Lee; Samuel P Meyers

2002-01-01

89

Positive charge of chitosan retards blood coagulation on chitosan films.  

PubMed

In this study, a series of chitosan films with different protonation degrees were prepared by deacidification with NaOH aqueous or ethanol solutions. The films were then used as a model to investigate the effects of the positive charge of chitosan on blood coagulation. The results showed that the positive charge of chitosan acted as a double-edged sword, in that it promoted erythrocyte adhesion, fibrinogen adsorption, and platelet adhesion and activation, but inhibited activation of the contact system. In contrast to prevailing views, we found that the positive charge of chitosan retarded thrombin generation and blood coagulation on these films. At least two reasons were responsible for this phenomenon. First, the positive charge inhibited the contact activation, and second, the positive charge could not significantly promote the activation of non-adherent platelets in the bulk phase during the early stage of coagulation. The present findings improve our understanding of the events leading to blood coagulation on chitosan films, which will be useful for the future development of novel chitosan-based hemostatic devices. PMID:22207609

He, Qing; Gong, Kai; Ao, Qiang; Ma, Tuo; Yan, Yufang; Gong, Yandao; Zhang, Xiufang

2011-12-29

90

Hemostatic Activity of Chitosan in Wound Management.  

National Technical Information Service (NTIS)

Research has continued on the preparation of a hemostatic agent in the form of a lyophilized sponge composed of chitosan glutamate and collagen. Characterization of the chitosan glutamate raw material has progressed; levels of metal and amino acid contami...

T. W. Lewis

1989-01-01

91

Hemostatic Activity of Chitosan in Wound Management.  

National Technical Information Service (NTIS)

The hemostatic activity of chitosan was first reported by Malette and Quigley. Olsen et al completed initial preclinical safety and efficacy studies on several physical terms of various chitosan salts and also elegant experiments which defined a possible ...

1996-01-01

92

Chitosan glucose complex – A novel food preservative  

Microsoft Academic Search

Chitosan glucose complex (CGC), a modified form of chitosan was prepared by heating chitosan with glucose. Fluorescence and the browning reaction of CGC indicated the presence of the Maillard reaction product (MRP). CGC showed excellent antioxidant activity while chitosan or glucose alone did not have any significant activity (p<0.05). The IC50 value of CGC for DPPH radical scavenging was 51.1?g\\/ml.

Sweetie R. Kanatt; Ramesh Chander; Arun Sharma

2008-01-01

93

Inactivation of coliphages by chitosan derivatives  

Microsoft Academic Search

The effect of chitosan fragments with different degrees of polymerization and the chemical derivatives of chitosan differing\\u000a in the number of amino groups and total molecule charge on phages T2, T4, and T7 was studied. The interaction of chitosan\\u000a with bacteriophage particles inactivated them to the extent dependent on the chemical properties of chitosan and its concentration.\\u000a Phage T2 was

Z. M. Kochkina; N. A. Surgucheva; S. N. Chirkov

2000-01-01

94

Chitosan-modified PLGA nanoparticles with versatile surface for improved drug delivery.  

PubMed

Shortage of functional groups on surface of poly(lactide-co-glycolide) (PLGA)-based drug delivery carriers always hampers its wide applications such as passive targeting and conjugation with targeting molecules. In this research, PLGA nanoparticles were modified with chitosan through physical adsorption and chemical binding methods. The surface charges were regulated by altering pH value in chitosan solutions. After the introduction of chitosan, zeta potential of the PLGA nanoparticle surface changed from negative charge to positive one, making the drug carriers more affinity to cancer cells. Functional groups were compared between PLGA nanoparticles and chitosan-modified PLGA nanoparticles. Amine groups were exhibited on PLGA nanoparticle surface after the chitosan modification as confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The modified nanoparticles showed an initial burst release followed by a moderate and sustained release profile. Higher percentage of drugs from cumulative release can be achieved in the same prolonged time range. Therefore, PLGA nanoparticles modified by chitosan showed versatility of surface and a possible improvement in the efficacy of current PLGA-based drug delivery system. PMID:23463262

Wang, Yichao; Li, Puwang; Kong, Lingxue

2013-03-06

95

Porous chitosan scaffolds for tissue engineering  

Microsoft Academic Search

The wide array of tissue engineering applications exacerbates the need for biodegradable materials with broad potential. Chitosan, the partially deacetylated derivative of chitin, may be one such material. In this study, we examined the use of chitosan for formation of porous scaffolds of controlled microstructure in several tissue-relevant geometries. Porous chitosan materials were prepared by controlled freezing and lyophilization of

Sundararajan V. Madihally; Howard W. T. Matthew

1999-01-01

96

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

97

ANTIBACTERIAL PROPERTIES OF CHITOSAN IN WATERBORNE PATHOGEN  

Microsoft Academic Search

The antimicrobial properties of chitosan, a derivative of chitin, were investigated in the solid and liquid culture against bacteria associated with waterborne disease in order to assess the potential for using chitosan as a natural disinfectant. Six strains which included three gram-negative and three gram-positive bacteria were studied. The effects of the deacetylation degree, concentration, and molecular weight of chitosan

Yen-Meng Chen; Ying-Chien Chung; Li Woan Wang; Kung-Tung Chen; Shyh-Yuan Li

2002-01-01

98

Palladium sorption on glutaraldehyde-crosslinked chitosan  

Microsoft Academic Search

The high nitrogen content of chitosan is the main reason for its ability to sorb metal ions through several mechanisms including ion-exchange or chelation, depending on the metal and the pH of the solution. Glutaraldehyde is used to crosslink chitosan through imine linkage between amine groups of chitosan and aldehyde groups of the crosslinking agent. This modified biosorbent was studied

Montserrat Ruiz; Ana Maria Sastre; Eric Guibal

2000-01-01

99

Chitosans for delivery of nucleic acids.  

PubMed

Alternatives to efficient viral vectors in gene therapy are desired because of their poor safety profiles. Chitosan is a promising non-viral nucleotide delivery vector because of its biocompatibility, biodegradability, low immunogenicity and ease of manufacturing. Since the transfection efficiency of chitosan polyplexes is relatively low compared to viral counterparts, there is an impetus to gain a better understanding of the structure-performance relationship. Recent progress in preparation and characterisation has enabled coupling analysis of chitosans structural parameters that has led to increased TE by tailoring of chitosan's structure. In this review, we summarize the recent advances that have lead to a more rational design of chitosan polyplexes. We present an integrated review of all major areas of chitosan-based transfection, including preparation, chitosan and polyplexes physicochemical characterisation, in vitro and in vivo assessment. In each, we present the obstacles to efficient transfection and the strategies adopted over time to surmount these impediments. PMID:23872012

Buschmann, Michael D; Merzouki, Abderrazzak; Lavertu, Marc; Thibault, Marc; Jean, Myriam; Darras, Vincent

2013-07-18

100

Spinning of hydroalcoholic chitosan solutions.  

PubMed

We investigated the spinning of hydroalcoholic chitosan solutions. The dope composition was optimized in order to obtain a continuous alcogel fiber by water evaporation on heating the extruded hydroalcoholic solution. This alcogel fiber was then neutralized in aqueous alkali baths and washed in water to eliminate the residual alcohol and salts before final drying. Depending on the alcohol content in the filament at the neutralization step, on specific alcohol-chitosan interactions and on the nature and concentration of the coagulation base, the process yielded semicrystalline chitosan fibers with different proportions of anhydrous and hydrated allomorphs. Contrarily to the classical annealing method, the formation of mainly anhydrous crystals was obtained without significant molecular weight decrease by neutralizing the polymer in hydrophobic conditions. The control of allomorph content was shown to be related to the hydrophobicity of the solvent (alcohol fraction) at the neutralization step. PMID:23987316

Desorme, Mylène; Montembault, Alexandra; Lucas, Jean-Michel; Rochas, Cyrille; Bouet, Thierry; David, Laurent

2013-05-04

101

Polyelectrolyte complexes of chitosan: formation, properties and applications  

NASA Astrophysics Data System (ADS)

The results of studies of polyelectrolyte complexes of chitosan are summarised and described systematically. Chitosan complexes with biopolyelectrolytes, with modified natural polyelectrolytes and with synthetic polyanions are considered. Medical and biotechnological applications of chitosan complexes are discussed.

Krayukhina, M. A.; Samoilova, N. A.; Yamskov, I. A.

2008-09-01

102

Blood contact properties of ascorbyl chitosan.  

PubMed

Ascorbyl chitosan was synthesized by heating chitosan with ascorbic acid in isopropanol. The products were characterized by FTIR and C-13 NMR spectroscopies, SEM, and elemental analysis. Blood contact properties of ascorbyl chitosans were evaluated. The ascorbyl chitosans demonstrated to have increased lipid-lowering activity in comparison to chitosan alone upon contact with human blood serum in in vitro conditions. Furthermore, the total cholesterol/HDL ratio was improved towards the desirable ideal values after three hours contact with ascorbyl chitosan samples. The lipid-lowering activity increased with ascorbyl substitution. The inherent nonspecific adsorption capability of chitosan due to its chelating power with several different functional groups was exhibited by ascorbyl chitosans as well. This behavior was exemplified in a simultaneous decrease in the total iron values of the volunteers together with lower lipid levels. Furthermore, ascorbyl chitosans were observed to have less hemocompatibility but increased anticoagulant activity when compared to chitosan alone. Additional in vivo studies are necessary to support these results and to investigate further the advantages and disadvantages of these materials to prove their safety prior to clinical applications. PMID:23862665

Yalinca, Z; Yilmaz, E; Taneri, B; Bullici, F; Tuzmen, S

2013-07-17

103

Alternate polyelectrolyte coating of chitosan beads for extending drug release.  

PubMed

In the present study, we addressed the factors modifying ciprofloxacin release from multiple coated beads. Beads were prepared by simple ionic cross-linking with sodium tripolyphoshate and coated with alginate and/or chitosan to prepare single, double, or multilayered beads. The water uptake capacity depended on the nature of beads (coated or uncoated) and pH of test medium. The number of coatings given to the beads influenced ciprofloxacin release rate. The coating significantly decreased the drug release from the beads in comparison to uncoated beads (p < 0.001). When the beads were given three coatings, viz., alginate, chitosan, and again alginate, the drug release appeared to follow the pattern exhibited by colon-targeted drug delivery systems with time dependent release behavior. The increase in coating formed a barrier for easy ingress of dissolution medium into the bead matrix, reducing the diffusion of drug. PMID:18379932

Srinatha, A; Pandit, Jayanta K

104

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.

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

2013-01-01

105

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

106

Chitosan-based gastrointestinal delivery systems  

Microsoft Academic Search

Chitosan, a natural polymer obtained by alkaline deacetylation of chitin, is non-toxic, biocompatible, and biodegradable. These properties make chitosan a good candidate for the development of conventional and novel gastrointestinal (GI) drug and gene delivery systems. The objective of this review is to summarize the recent applications of chitosan in oral and\\/or buccal delivery, stomach-specific drug delivery, intestinal delivery, and

Radi Hejazi; Mansoor Amiji

2003-01-01

107

Antibacterial hydrogel coating by electrophoretic co-deposition of chitosan/alkynyl chitosan.  

PubMed

Despite much effort has been paid to develop aseptic implant devices, the infection associated with medical implant still remains a significant problem. Here, we report a potential coating material derived from a natural biopolymer chitosan. Firstly, chitosan functionalized with alkynyl moiety (ACS) was prepared by reaction between chitosan and 3-bromopropyne. The structure of the alkynyl chitosan was characterized by FT-IR, (1)H NMR, XRD, TGA and element analysis. The minimum inhibitory concentration (MIC) of ACS with a degree of substitution (DS) of 0.40 was 0.03% against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Subsequently, the alkynyl chitosan was co-deposited with chitosan on stainless steel wire to fabricate a composite hydrogel. The composite hydrogel exhibited better antibacterial activities than pure chitosan hydrogel. PMID:24053838

Ding, Fuyuan; Nie, Zhen; Deng, Hongbing; Xiao, Ling; Du, Yumin; Shi, Xiaowen

2013-07-29

108

Air plasma treated chitosan fibers-stacked scaffolds  

Microsoft Academic Search

Chitosan is a nontoxic, biodegradable and biocompatible polymer. Rapid prototyped chitosan scaffolds were manufactured by liquid-frozen deposition of chitosan fibers in this study. To investigate if the air plasma (AP) treatment could be used to improve the surface properties of these scaffolds for cell attachment, chitosan films were first prepared and treated with AP under different conditions. Under the optimized

Shan-hui Hsu; Chen-Huan Lin; Ching-Shiow Tseng

2012-01-01

109

Biopolymer chitosan\\/montmorillonite nanocomposites: Preparation and characterization  

Microsoft Academic Search

Biopolymer chitosan\\/montmorillonite nanocomposites have been prepared in which montmorillonite (MMT) is used as nanofiller and diluted acetic acid is used as solvent for dissolving and dispersing chitosan and montmorillonite. Morphology and properties of chitosan nanocomposites with and without acetic acid residue have been studied compared with those of pure chitosan. The effect of acetic acid residue and MMT loading in

S. F. Wang; L. Shen; Y. J. Tong; L. Chen; I. Y. Phang; P. Q. Lim; T. X. Liu

2005-01-01

110

Physicochemical characterization and antibacterial property of chitosan acetates  

Microsoft Academic Search

In a new approach to the preparation of solid chitosan acetate, the dependence of solubility of chitsoan acetate on the mole ratio of acetic acid to GlcN residues of chitosan was evaluated from turbidity. The structure of the product chitosan acetate was characterized by titration and FT-IR. It was demonstrated that the chitosan acetate with high solubility retained the structure

Yan Li; Xi Guang Chen; Nan Liu; Cheng Sheng Liu; Chen Guang Liu; Xiang Hong Meng; Le Jun Yu; John F. Kenendy

2007-01-01

111

Effect of chitosan content on gel content of epoxized natural rubber grafted with chitosan in latex form.  

PubMed

The epoxidized natural rubber (ENR) latex-g-chitosan (ENR-g-chitosan) was prepared in latex form using potassium persulphate as an initiator. Firstly, the reduction in molecular weight of chitosan was subjected to the addition of K2S2O8 at 70 °C for 15 min. The structure of the modified chitosan was characterized by ATR-FTIR. Secondarily, the influence of chitosan contents, reaction time, and temperature and K2S2O8 concentrations on the gel content of the modified ENR was investigated. The chemical structure of the ENR-g-chitosan was confirmed by (1)H-NMR and ATR-FTIR. The ether linkage of the ENR-g-chitosan was conformed at 1154 an 1089 cm(-1) by ATR-FTIR and 3.60 ppm by (1)H-NMR. The gel content of ENR-g-chitosan at 5% chitosan showed the highest value compared with other samples. But when chitosan increased from 5% to 10% or 20%, the gel content of ENR-g-chitosan dramatically decreased. The ENR-g-chitosan showed good thermal resistance due to incorporation of chitosan. The morphology of ENR-g-chitosan particle showed the core-shell structure observed by TEM. The optimum condition of grafting ENR with chitosan was found at 65°C for 3h of reaction time, ratio of ENR/chitosan at 9:1. PMID:23827540

Riyajan, Sa-Ad; Sukhlaaied, Wattana

2012-11-20

112

Study of glycol chitosan-carboxymethyl ?-cyclodextrins as anticancer drugs carrier.  

PubMed

Efficient target delivery system for insoluble anticancer drugs to increase the intracellular drug concentration has become a focus in cancer therapy. Herein, glycol chitosan-carboxymethyl ?-cyclodextrins (G-chitosan-CM-dextrins) was synthesized for delivering different hydrophobic anticancer drugs. Surface plasmon resonance and UV-vis spectroscopy results showed that all the three anticancer drugs (5-fluorouracil, doxorubicin, and vinblastine) could be successfully loaded into the cavities of the covalently linked CM-dextrins. Moreover, the free carboxymethyl groups could enhance the binding interactions between the covalently linked CM-dextrins and anticancer drugs. Release behaviors with pH changes of the three drugs were also explored, result showed different drugs would be released by different ways, as for doxorubicin, pH sensitive release has been realized. The obtained G-chitosan-CM-dextrins carrier has both mucoadhesive property of G-chitosan and hydrophobic cavities of ?-cyclodextrins. Therefore, the new synthesized G-chitosan-CM-dextrins carrier exhibits a promising potential capability for anticancer drug delivery in tumor therapy. PMID:23499111

Tan, Haina; Qin, Fei; Chen, Dongfeng; Han, Songbai; Lu, Wu; Yao, Xin

2012-12-25

113

Efficient mucosal delivery of optical contrast agents using imidazole-modified chitosan  

NASA Astrophysics Data System (ADS)

The clinical applicability of antibodies and plasmonic nanosensors as topically applied, molecule-specific optical diagnostic agents for noninvasive early detection of cancer and precancer is severely limited by our inability to efficiently deliver macromolecules and nanoparticles through mucosal tissues. We have developed an imidazole-functionalized conjugate of the polysaccharide chitosan (chitosan-IAA) to enhance topical delivery of contrast agents, ranging from small molecules and antibodies to gold nanoparticles up to 44 nm in average diameter. Contrast agent uptake and localization in freshly resected mucosal tissues was monitored using confocal microscopy. Chitosan-IAA was found to reversibly enhance mucosal permeability in a rapid, reproducible manner, facilitating transepithelial delivery of optical contrast agents. Permeation enhancement occurred through an active process, resulting in the delivery of contrast agents via a paracellular or a combined paracellular/transcellular route depending on size. Coadministration of epidermal growth factor receptor-targeted antibodies with chitosan-IAA facilitated specific labeling and discrimination between paired normal and malignant human oral biopsies. Together, these data suggest that chitosan-IAA is a promising topical permeation enhancer for mucosal delivery of optical contrast agents.

Ghosn, Bilal; van de Ven, Anne L.; Tam, Justina; Gillenwater, Ann; Sokolov, Konstantin V.; Richards-Kortum, Rebecca; Roy, Krishnendu

2010-01-01

114

Biocompatibility of chitosan-coated iron oxide nanoparticles with osteoblast cells  

PubMed Central

Background: Bone disorders (including osteoporosis, loosening of a prosthesis, and bone infections) are of great concern to the medical community and are difficult to cure. Therapies are available to treat such diseases, but all have drawbacks and are not specifically targeted to the site of disease. Chitosan is widely used in the biomedical community, including for orthopedic applications. The aim of the present study was to coat chitosan onto iron oxide nanoparticles and to determine its effect on the proliferation and differentiation of osteoblasts. Methods: Nanoparticles were characterized using transmission electron microscopy, dynamic light scattering, x-ray diffraction, zeta potential, and vibrating sample magnetometry. Uptake of nanoparticles by osteoblasts was studied by transmission electron microscopy and Prussian blue staining. Viability and proliferation of osteoblasts were measured in the presence of uncoated iron oxide magnetic nanoparticles or those coated with chitosan. Lactate dehydrogenase, alkaline phosphatase, total protein synthesis, and extracellular calcium deposition was studied in the presence of the nanoparticles. Results: Chitosan-coated iron oxide nanoparticles enhanced osteoblast proliferation, decreased cell membrane damage, and promoted cell differentiation, as indicated by an increase in alkaline phosphatase and extracellular calcium deposition. Chitosan-coated iron oxide nanoparticles showed good compatibility with osteoblasts. Conclusion: Further research is necessary to optimize magnetic nanoparticles for the treatment of bone disease.

Shi, Si-Feng; Jia, Jing-Fu; Guo, Xiao-Kui; Zhao, Ya-Ping; Chen, De-Sheng; Guo, Yong-Yuan; Cheng, Tao; Zhang, Xian-Long

2012-01-01

115

Efficient mucosal delivery of optical contrast agents using imidazole-modified chitosan  

PubMed Central

The clinical applicability of antibodies and plasmonic nanosensors as topically applied, molecule-specific optical diagnostic agents for noninvasive early detection of cancer and precancer is severely limited by our inability to efficiently deliver macromolecules and nanoparticles through mucosal tissues. We have developed an imidazole-functionalized conjugate of the polysaccharide chitosan (chitosan-IAA) to enhance topical delivery of contrast agents, ranging from small molecules and antibodies to gold nanoparticles up to 44 nm in average diameter. Contrast agent uptake and localization in freshly resected mucosal tissues was monitored using confocal microscopy. Chitosan-IAA was found to reversibly enhance mucosal permeability in a rapid, reproducible manner, facilitating transepithelial delivery of optical contrast agents. Permeation enhancement occurred through an active process, resulting in the delivery of contrast agents via a paracellular or a combined paracellular?transcellular route depending on size. Coadministration of epidermal growth factor receptor–targeted antibodies with chitosan-IAA facilitated specific labeling and discrimination between paired normal and malignant human oral biopsies. Together, these data suggest that chitosan-IAA is a promising topical permeation enhancer for mucosal delivery of optical contrast agents.

Ghosn, Bilal; van de Ven, Anne L.; Tam, Justina; Gillenwater, Ann; Sokolov, Konstantin V.; Richards-Kortum, Rebecca; Roy, Krishnendu

2010-01-01

116

Improvement of the yield of physiologically active oligosaccharides in continuous hydrolysis of chitosan using immobilized chitosanases.  

PubMed

The continuous production of chitosan oligosaccharides using a packed-bed enzyme reactor was investigated as to the effects of the operation conditions on the yield of pentamers and hexamers of chitosan oligosaccharides. A column reactor packed with immobilized chitosanases prepared by the multipoint attachment method was used for continuous hydrolysis of chitosan. In this reactor, the decrease of the yield of the target intermediate oligosaccharides due to axial mixing was negligible. The surface enzyme density of the support and flow rate of the substrate solution significantly affected the maximum yield of pentamers and hexamers. These effects were summarized as a correlation with the Damköhler number (Da), defined as the ratio of the maximum reaction rate to the maximum mass transfer rate. The optimum condition was determined based on Da. Under the optimized condition (Da = 0.12), pentamers and hexamers could be produced continuously for a month with a yield of over 35% (7 kg/m(3) in concentration). PMID:12910551

Kuroiwa, Takashi; Ichikawa, Sosaku; Sato, Seigo; Mukataka, Sukekuni

2003-10-01

117

Magnetic and fluorescent multifunctional chitosan nanoparticles as a smart drug delivery system  

NASA Astrophysics Data System (ADS)

An innovative drug delivery system based on magnetic and fluorescent multifunctional chitosan nanoparticles was developed, which combined magnetic targeting, fluorescent imaging and stimulus-responsive drug release properties into one drug delivery system. Water-soluble superparamagnetic Fe3O4 nanoparticles, CdTe quantum dots (QDs) and pharmaceutical drugs were simultaneously incorporated into chitosan nanoparticles; cross-linking the composite particles with glutaraldehyde tailored their size, morphology, surface properties and drug release behaviors. The system showed superparamagnetic and strong fluorescent properties, and was used as a controlled drug release vehicle, which showed pH-sensitive drug release over a long time. The composite magnetic and fluorescent chitosan nanoparticles are potential candidates as a smart drug delivery system.

Li, Linlin; Chen, Dong; Zhang, Yanqi; Deng, Zhengtao; Ren, Xiangling; Meng, Xianwei; Tang, Fangqiong; Ren, Jun; Zhang, Lin

2007-10-01

118

Template synthesized chitosan nano test tubes for drug delivery applications  

NASA Astrophysics Data System (ADS)

There is tremendous current interest in developing nanoscale drug delivery vehicles. Though intensive efforts have focused on developing spherical drug delivery vehicles, cylindrically shaped vehicles such as nanotubes offer many advantages. Typically, nanotubes can carry a larger inner payload than nanoparticles of the same diameter. Also, we can prepare nanotubes in templates whose geometries can be controlled, in turn allowing precise control over the length and diameter of the tubes. In addition, template synthesized nanotubes can be differentially functionalized on the inner and outer surfaces. Furthermore, templates that are closed on one end can be used to fabricate nano test tubes (closed on one end). The geometry of these nano test tubes allows them to be easily filled with a payload, the open end sealed with a nanoparticle to protect the payload from leaking out, and then the exterior of the tube can be functionalized with a targeting moiety. In an effort to develop such a system, we explored the fabrication of chitosan nano test tubes. Defect-free, chitosan nano test tubes of uniform size were synthesized within the pores of a nanoporous alumina template membrane. While the nano test tubes remained within the template membrane, their inner cavities were filled with a model payload. The payload was then trapped inside the nano test tubes by sealing the open ends of the tubes with latex nanoparticle caps. For proof-of-principle studies, imine linkages were used to attach the caps to the nano test tubes. To create a self-disassembling system, disulfide chemistry was used to covalently cap the nano test tubes. Once removed from the template, the exterior of the nano test tubes were modified with a targeting moiety, allowing them to be targeted to pathological sites. We have also shown that the chitosan nano test tubes are biodegradable by two systems: enzymatic cleavage by lysozymes and disulfide cleavage of the crosslinker by reducing environments (glutathione) found within cells. Therefore, once the nano test tubes reach their target site and are taken into a cell, the tubes can be degraded and release their payload. This chitosan nano test tube delivery stystem shows great potential for applications in targeted drug delivery. (Full text of this dissertation may be available via the University of Florida Libraries web site. Please check http://www.uflib.ufl.edu/etd.html)

Perry, Jillian L. Moulton

119

Chitin-chitosan: Properties, benefits and risks  

Microsoft Academic Search

A beneficial effect of chitin-chitosan as a food supplement is the reduction of plasma cholesterol and triglycerides due to its ability to bind dietary lipids, thereby reducing intestinal lipid absorption. The hypolipidemic influence of chitosan may also be due to interruption of the enterohepatic bile acid circulation. Plasma cholesterol in animals on cholesterol-free diet, however, is not affected, indicating that

S. S. Koide

1998-01-01

120

Chitosan nanoparticles as delivery systems for doxorubicin  

Microsoft Academic Search

The aim of this paper was to evaluate the potential of chitosan nanoparticles as carriers for the anthracycline drug, doxorubicin (DOX). The challenge was to entrap a cationic, hydrophilic molecule into nanoparticles formed by ionic gelation of the positively charged polysaccharide chitosan. To achieve this objective, we attempted to mask the positive charge of DOX by complexing it with the

Kevin A. Janes; Marie P. Fresneau; Ana Marazuela; Angels Fabra; Mar??a José Alonso

2001-01-01

121

Hemostatic Agents Derived from Chitin and Chitosan  

Microsoft Academic Search

A recent review detailing the role of new hemostatic agents for battlefield hemorrhage control describes the interest in and necessary specifications for such materials. As a consequence, the Defense Department authorized the development and use of three deployable and FDA approved hemostatic agents: Zeolite “Quikclot” and chitosanic “Hemcon” and the American Red Cross Fibrin Dressing. Although chitosan has a number

Hyun Suk Whang; Wolff Kirsch; Yong H. Zhu; Cheng Z. Yang; Samuel M. Hudson

2005-01-01

122

Conductivity study of chitosan based nanocomposites  

NASA Astrophysics Data System (ADS)

Bio polymer like chitosan is dissolved in acids like formic and acetic acid and CdS nano particle prepared by chemical methods has been embedded in the salts of chitosan matrix. The viscous solution is cast into film on the glass substrate using spin coating method and their ionic conductivity has been studied for various frequencies and temperatures.

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

2012-06-01

123

Functional properties of chitosan-based films.  

PubMed

Chitosan-based films plasticized with glycerol were prepared by casting with the aim to obtain environmentally friendly materials for packaging applications. Different contents of glycerol were incorporated into chitosan solutions to improve mechanical properties and all films obtained were flexible and transparent. It was observed that the transparency and good behaviour of the films against UV radiation were not affected by chitosan molecular weight or glycerol content. Moreover, chitosan-based films exhibited excellent barrier properties against water vapour and oxygen, even with the addition of glycerol. The effect of the plasticizer on the properties has been explained using Fourier transform infrared (FTIR) spectroscopic analysis. The changes observed in the intensity of the bands showed that glycerol interacts with chitosan, which could be confirmed by total soluble matter (TSM). PMID:23465939

Leceta, I; Guerrero, P; de la Caba, K

2012-04-20

124

Transfection efficiency of chitosan and thiolated chitosan in retinal pigment epithelium cells: A comparative study  

PubMed Central

OBJECTIVE: Gene therapy relies on efficient vector for a therapeutic effect. Efficient non-viral vectors are sought as an alternative to viral vectors. Chitosan, a cationic polymer, has been studied for its gene delivery potential. In this work, disulfide bond containing groups were covalently added to chitosan to improve the transfection efficiency. These bonds can be cleaved by cytoplasmic glutathione, thus, releasing the DNA load more efficiently. MATERIALS AND METHODS: Chitosan and thiolated chitosan nanoparticles (NPs) were prepared in order to obtain a NH3+:PO4? ratio of 5:1 and characterized for plasmid DNA complexation and release efficiency. Cytotoxicity and gene delivery studies were carried out on retinal pigment epithelial cells. RESULTS: In this work, we show that chitosan was effectively modified to incorporate a disulfide bond. The transfection efficiency of chitosan and thiolated chitosan varied according to the cell line used, however, thiolation did not seem to significantly improve transfection efficiency. CONCLUSION: The apparent lack of improvement in transfection efficiency of the thiolated chitosan NPs is most likely due to its size increase and charge inversion relatively to chitosan. Therefore, for retinal cells, thiolated chitosan does not seem to constitute an efficient strategy for gene delivery.

Oliveira, Ana V.; Silva, Andreia P.; Bitoque, Diogo B.; Silva, Gabriela A.; Rosa da Costa, Ana M.

2013-01-01

125

Antioxidant activity of high molecular weight chitosan and N,O-quaternized chitosans.  

PubMed

The objective of this study was to evaluate the in vitro antioxidant activity of high molecular weight chitosan based films. Three kinds of water-soluble quaternized chitosans with high molecular weight, namely N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (400-HTCC and 1240-HTCC), N-(2-hydroxyl) propyl-3-triethyl ammonium chitosan chloride (400-HTEC and 1240-HTEC), and O-(2-hydroxyl) propyl-3- trimethyl ammonium chitosan chloride (400-O-HTCC) were prepared from high molecular weight chitosans (400 and 1240 kDa). The in vitro antioxidant activity of a high molecular weight chitosan (1240-CS) and five quaternized chitosans was evaluated and compared as radical scavengers against 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH•), hydroxyl radical (•OH), and superoxide radical (•O2(-)) using established methods, and the effect of the molecular weight, the concentration, the newly generated hydroxyl group, the extra introduced positive charge of quaternary ammonium salt group, etc., on the antioxidant activity of these high molecular weight chitosans is discussed. The data obtained in vitro models exhibited good antioxidant potency and suggested the possibility that high molecular weight chitosan based films could be effectively employed as natural antioxidant materials for application in the field of food and medicine. PMID:23706102

Wan, Ajun; Xu, Qing; Sun, Yan; Li, Huili

2013-07-08

126

Effect of collagen II coating on mesenchymal stem cell adhesion on chitosan and on reacetylated chitosan fibrous scaffolds  

Microsoft Academic Search

The biocompatibility and biomimetic properties of chitosan make it attractive for tissue engineering but its use is limited\\u000a by its cell adhesion properties. Our objectives were to produce and characterize chitosan and reacetylated-chitosan fibrous\\u000a scaffolds coated with type II collagen and to evaluate the effect of these chemical modifications on mesenchymal stem cell\\u000a (MSC) adhesion. Chitosan and reacetylated-chitosan scaffolds obtained

Guillaume R. RagetlyDominique; Dominique J. Griffon; Hae-Beom Lee; Yong Sik Chung

2010-01-01

127

Preparation and characterization of ampicillin loaded methylpyrrolidinone chitosan and chitosan microspheres  

Microsoft Academic Search

Ampicillin was embedded in microparticles made of a new derivative of chitosan: methylpyrrolidinone chitosan. They were prepared using different drug-to-polymer weight ratios and by a spray-drying technique. Spray-dried drug-loaded chitosan microspheres were prepared for comparison. The microparticles were characterized by scanning electron microscopy (SEM), particle size analysis, differential scanning calorimetry (DSC) and in vitro drug release. Microbiological assay was performed

P. Giunchedi; I. Genta; B. Conti; R. A. A. Muzzarelli; U. Conte

1998-01-01

128

Characterization and comparison of chitosan\\/PVP and chitosan\\/PEO blend films  

Microsoft Academic Search

The objective of this study was to investigate and compare the physical and functional properties of chitosan films prepared with poly (N-vinyl-2-pyrrolidone) (PVP) and polyethylene oxide (PEO). Addition of PVP or PEO reduced yellowish coloration of chitosan-based films and made the films easier to puncture and tear. Contrary to chitosan\\/PEO films, where addition of PEO had tendency to reduce water

J. Li; S. Zivanovic; P. M. Davidson; K. Kit

2010-01-01

129

Green synthesis approach: extraction of chitosan from fungus mycelia.  

PubMed

Chitosan, copolymer of glucosamine and N-acetyl glucosamine is mainly derived from chitin, which is present in cell walls of crustaceans and some other microorganisms, such as fungi. Chitosan is emerging as an important biopolymer having a broad range of applications in different fields. On a commercial scale, chitosan is mainly obtained from crustacean shells rather than from the fungal sources. The methods used for extraction of chitosan are laden with many disadvantages. Alternative options of producing chitosan from fungal biomass exist, in fact with superior physico-chemical properties. Researchers around the globe are attempting to commercialize chitosan production and extraction from fungal sources. Chitosan extracted from fungal sources has the potential to completely replace crustacean-derived chitosan. In this context, the present review discusses the potential of fungal biomass resulting from various biotechnological industries or grown on negative/low cost agricultural and industrial wastes and their by-products as an inexpensive source of chitosan. Biologically derived fungal chitosan offers promising advantages over the chitosan obtained from crustacean shells with respect to different physico-chemical attributes. The different aspects of fungal chitosan extraction methods and various parameters having an effect on the yield of chitosan are discussed in detail. This review also deals with essential attributes of chitosan for high value-added applications in different fields. PMID:23078670

Dhillon, Gurpreet Singh; Kaur, Surinder; Brar, Satinder Kaur; Verma, Mausam

2012-10-18

130

Bioavailability enhancement of glucosamine hydrochloride by chitosan.  

PubMed

Glucosamine, as a dietary supplement for management of osteoarthritis, has a low and erratic oral bioavailability due to its transport-mediated absorption and presystemic loss in liver and GI tract. The present study described an effective approach to improve glucosamine intestinal absorption and hence its bioavailability using chitosan. Effects of chitosan on intestinal permeability and pharmacokinetics of glucosamine were evaluated in Caco-2 cell monolayer and rats, respectively. In addition, randomized crossover pharmacokinetic studies in beagle dogs were performed to evaluate the oral bioavailabilities of the developed glucosamine oral formulations containing chitosan (QD-Glu solution and QD-Glu tablet) in comparison to its commercial products. Caco-2 permeability studies demonstrated that chitosan could enhance the absorptive transport of glucosamine by 1.9-4.0-fold via the reversible opening of the cell tight junction. After oral administration of glucosamine solutions containing chitosan in rats, it was found that 0.5% (w/v) chitosan exhibited the highest enhancement in Cmax (2.8-fold) and AUC0-? (2.5-fold) of glucosamine. Further pharmacokinetic studies in beagle dogs demonstrated that QD-Glu solution and QD-Glu tablet showed much higher relative bioavailabilities of 313% and 186%, when comparing with Wellesse™ solution and Voltaflex™ tablet, respectively. In conclusion, chitosan could serve as a promising oral absorption enhancer for glucosamine. PMID:23830943

Qian, Shuai; Zhang, Qizhi; Wang, Yanfeng; Lee, Benjamin; Betageri, Guru V; Chow, Moses S S; Huang, Min; Zuo, Zhong

2013-07-03

131

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

132

Synthesis of aligned hematite nanoparticles on chitosan-alginate films.  

PubMed

Iron oxide nanoparticles are being viewed with interest owing to the great potential they have in the biomedical applications like MRI contrast enhancement, targeted drug delivery, hyperthermia and recently in magnetic separation of cancer cells from the body. Templated synthesis has been considered ideal for synthesis of iron oxide nanoparticles as particles are attracted magnetically, in addition to usual flocculation through van der Waals attraction. Biological templates are attractive owing to their biocompatibility and the attractive porosity and surface chemistry that nature provides. Polysaccharides like chitosan and alginate have been employed in the synthesis of a polyion complex, which provided the active-binding sites for iron(II) ions in solution to bind. The natural organization of chitosan and alginate into a porous film has been exploited to synthesize spherical iron oxide nanoparticles through careful calcination of the iron(II) conjugate film. Our experiments indicate that the formed nanoparticles are highly crystalline, confirm to the hematite structure and have a superparamagnetic response with a low coercivity of 116Oe. Particles thus synthesized were highly monodisperse with hydrodynamic diameter of 1.8 nm. The symmetric porosity of the film translates into the synthesis of well-aligned nanoparticles of iron oxide. Compared to synthesis in solution, the film-assisted synthesis offered a greater degree of control over the particle size distribution pattern, with the chitosan-alginate template providing the needed spatial separation to prevent the aggregation due to magnetostatic coupling. Such hematite nanoparticles can either be used directly or converted to paramagnetic magnetite by reduction. Zeta potential measurements indicate highly stable nanoparticles, which can therefore be conjugated to cationic liposomes carrying drugs and magnetically guided to target sites. PMID:19303261

Sreeram, Kalarical Janardhanan; Nidhin, Marimuthu; Nair, Balachandran Unni

2009-03-03

133

Chitosan and lactic acid-grafted chitosan nanoparticles as carriers for prolonged drug delivery  

PubMed Central

Nanoparticles of ~10 nm in diameter made with chitosan or lactic acid-grafted chitosan were developed for high drug loading and prolonged drug release. A drug encapsulation efficiency of 92% and a release rate of 28% from chitosan nanoparticles over a 4-week period were demonstrated with bovine serum protein. To further increase drug encapsulation, prolong drug release, and increase chitosan solubility in solution of neutral pH, chitosan was modified with lactic acid by grafting D,L-lactic acid onto amino groups in chitosan without using a catalyst. The lactic acid-grafted chitosan nanoparticles demonstrated a drug encapsulation efficiency of 96% and a protein release rate of 15% over 4 weeks. With increased protein concentration, the drug encapsulation efficiency decreased and drug release rate increased. Unlike chitosan, which is generally soluble only in acid solution, the chitosan modified with lactic acid can be prepared from solutions of neutral pH, offering an additional advantage of allowing proteins or drugs to be uniformly incorporated in the matrix structure with minimal or no denaturization.

Bhattarai, Narayan; Ramay, Hassna R; Chou, Shinn-Huey; Zhang, Miqin

2006-01-01

134

Magnetic retrieval of chitosan: extraction of bioactive constituents from green tea beverage samples.  

PubMed

A new solid-phase extraction mode for magnetic retrieval of chitosan combined with high-performance liquid chromatography-diode array detection was proposed for the pre-concentration and determination of flavonoids in green tea beverage samples. In the experiment, chitosan was used as sorbents for the extraction of target analytes; after completion of the extraction process, Fe(3)O(4) nanoparticles acted as carrier to retrieve chitosan from the sample solution. Some important parameters influenced extraction efficiency of flavonoids, including the extraction mode, amounts of chitosan, pH of sample solution, extraction time, salt addition, amounts of Fe(3)O(4) nanoparticles, desorption solvent and desroption time, were optimized. Under the optimum conditions, the recoveries of analytes done on samples spiked with the target analytes were between 96.4% and 108.6%; relative standard deviations ranged from 0.6% to 8.7%. The correlation coefficients varied from 0.9917 to 0.9988. The limits of detection ranged from 5.4 to 16.8 ng mL(-1) at a signal-to-noise ratio of 3. All four different brands of green tea beverage samples were successfully analyzed by the proposed method. PMID:22167525

Zhang, Hong-Fei; Shi, Yan-Ping

2011-12-13

135

Simulation of skin permeability in chitosan membranes.  

PubMed

To provide an alternative means of evaluating transdermal drug delivery systems, membranes of chitosan were developed. The membranes were prepared by cast-drying method. The effects of chitosan concentration, sodium tripolyphosphate (NaTPP) concentration and crosslinking (CL) time on flux and lag time were studied using central composite design. It was observed that chitosan membrane at a particular composition simulated the permeation of diclofenac sodium through rat skin The mathematical model developed in the present study can be used to simulate the permeation of drugs through different species of animal skins. PMID:11165107

Dureja, H; Tiwary, A K; Gupta, S

2001-02-01

136

Electrospun antibacterial chitosan-based fibers.  

PubMed

Chitosan is non-toxic, biocompatible, and biodegradable polysaccharide from renewable resources, known to have inherent antibacterial activity, which is mainly due to its polycationic nature. The combining of all assets of chitosan and its derivatives with the unique properties of electrospun nanofibrous materials is a powerful strategy to prepare new materials that can find variety of biomedical applications. In this article the most recent studies on different approaches for preparation of antibacterial fibrous materials from chitosan and its derivatives such as electrospinning, coating, and electrospinning-electrospraying, loading of drugs or bioactive nanoparticles are summarized. PMID:23754600

Ignatova, Milena; Manolova, Nevena; Rashkov, Iliya

2013-06-10

137

The antimicrobial action of chitosan, low molar mass chitosan, and chitooligosaccharides on human colonic bacteria.  

PubMed

Antibacterial effect of chitooligosaccharides (COS) and low molar mass chitosans (LMWC) is considered as one of the most important characteristics of chitosan (CS) hydrolysates. Here, we show the in vitro effect of different COS, LMWC, and CS on representative anaerobic bacteria isolated from human colon as a possibility of targeting modification of colonic microflora composition by supplementation of dietary CS products by humans. Specific growth rate of seven selected nonpathogenic anaerobic bacterial strains (Clostridium paraputrificum, Clostridium beijerinckii, Roseburia intestinalis, Bacteroides vulgatus, Bacteriodes thetaiotaomicron, Faecalibacterium prausnitzii and Blautia coccoides) was determined in the presence of 0.25 and 0.5% COS (2, 3, and 6 kDa), 0.025 and 0.05% of LMWC (10 and 16 kDa), and 0.025 and 0.1% of CS in vitro. The growth rate decreased in all strains in the presence of COS and LMWC in higher concentrations in comparison to control incubations. A relatively higher resistance to CS hydrolyzates was detected in R. intestinalis and F. prausnitzii, and more susceptible were bacteria belonging to Bacteoides sp. and Clostridium sp. The antimicrobial activity, minimum inhibitory concentrations (MIC), and minimal bactericidal concentrations (MBC) were determined. The antimicrobial activity increased with the degree of polymerization (DP). MIC ranged from 0.25 to 4.5% in dependence on bacterial strain and DP of CS/LMWC. MBC also decreased with DP. The most effective antimicrobial action was detected in LMWC with 16 kDa and CS. Weak antimicrobial activity was found in COS with small molecules (2 and 3 kDa). PMID:22528310

Sim?nek, Ji?í; Brandysová, V?ra; Koppová, Ingrid; Sim?nek, Ji?í

2012-04-13

138

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

139

Antimicrobial N-halamine modified chitosan films.  

PubMed

The inherent antimicrobial properties and biodegradability of chitosan make it an ideal candidate for antimicrobial materials. In this study, N-halamine precursor 3-glycidyl-5,5-dimethylhydantoin (GH) was synthesized and bonded onto chitosan by a ring opening reaction between chitosan and GH. The chitosan film modified with the N-halamine precursor could be rendered biocidal after exposure to a dilute household bleach solution. Syntheses routes, characterization data, and antimicrobial test results are presented. The chlorinated films with 2.60 × 10(18) atoms/cm(2) of active chlorine were challenged with Staphylococcus aureus (ATCC 6538) and Escherichia coli O157:H7 (ATCC 43895) and showed good efficacy against these two bacterial species with log reductions of 7.4 and 7.5 within 10 and 5 min of contact time, respectively. These films may serve as potential materials for food packaging and biomedical applications. PMID:23218332

Li, Rong; Hu, Pei; Ren, Xuehong; Worley, S D; Huang, T S

2012-09-07

140

Novel water-soluble photosensitizers from chitosan.  

PubMed

Novel water-soluble polymeric photosensitizers based on the natural polymer chitosan were synthesized and studied. The modified chitosans contain covalently attached Rose Bengal. The polymers absorb light from the visible spectral region and generate singlet oxygen. They can serve as environmentally friendly, biodegradable polymeric photosensitizers, which can use light from a visible spectral region to initiate photooxidation of organic compounds in water. PMID:17291066

Moczek, ?ukasz; Nowakowska, Maria

2007-02-01

141

Chitosan/Prussian blue-based biosensors  

NASA Astrophysics Data System (ADS)

Chitosan/Prussian blue (PB) based biosensors, including a glucose sensor, a glutamate sensor and a galactose sensor have been developed. The biosensors exhibit excellent performance; in particular, the interference of ascorbic and uric acids can be avoided due to selective permeability of chitosan film and electro-catalysis of the PB layer to H2O2. The biosensors have been applied to detect glucose, galactose and glutamate in human blood serum and fermented solution.

Wang, Yiting; Zhu, Jianzhong; Zhu, Rongjin; Zhu, Ziqiang; Lai, Zongsheng; Chen, Zongyou

2003-06-01

142

Biophysical studies on chitosan-coated liposomes  

Microsoft Academic Search

Liposomes have been used as delivery vehicles for stabilizing drugs, overcoming barriers to cellular and tissue uptake, and\\u000a for directing their contents toward specific sites in vivo. Chitosan is a biological macromolecule derived from crustacean\\u000a shells and has several emerging applications in drug development, obesity control, and tissue engineering. In the present\\u000a work, the interaction between chitosan and dipalmitoyl phosphatidylcholine

Mohsen M. Mady; Mirhane M. Darwish; Safaa Khalil; Wafaa M. Khalil

2009-01-01

143

Multiparticulate System for Colon Targeted Delivery of Ondansetron  

PubMed Central

Targeted delivery of drugs to colon has the potential for local treatment of a variety of colonic diseases. The main objective of the study was to develop a multiparticulate system containing chitosan microspheres for the colon targeted delivery of ondansetron for the treatment of irritable bowel syndrome. This work combines pH-dependent solubility of eudragit S-100 polymers and microbial degradability of chitosan polymers. Chitosan microspheres containing ondansetron were prepared by emulsion cross linking method. The effect of process variables like chitosan concentration, drug-polymer ratio, emulsifier concentration and stirring speed were studied on particle size and entrapment efficiency of chitosan microspheres. In vitro drug release studies in simulated gastro intestinal fluids showed a burst drug release pattern in the initial hour necessitating microencapsulation around the chitosan microspheres. The optimized formulation was then subjected to microencapsulation with eudragit S-100 by solvent evaporation technique. The effect of different coat/core ratio on particle size, drug entrapment efficiency and in vitro drug release were studied. Formulation which contain 1:10 core/coat ratio released lesser amount of drug in the upper gastro intestinal conditions and so selected as best formulation and then subjected to in vitro drug release studies in presence of rat ceacal contents to assess biodegradability of chitosan microspheres in colon. In order to study the drug release mechanism in vitro drug release data was fitted into various kinetic models. Analysis of regression values suggested that the possible drug release mechanism was Peppas model.

Jose, S.; Dhanya, K.; Cinu, T. A.; Aleykutty, N. A.

2010-01-01

144

Multiparticulate system for colon targeted delivery of ondansetron.  

PubMed

Targeted delivery of drugs to colon has the potential for local treatment of a variety of colonic diseases. The main objective of the study was to develop a multiparticulate system containing chitosan microspheres for the colon targeted delivery of ondansetron for the treatment of irritable bowel syndrome. This work combines pH-dependent solubility of eudragit S-100 polymers and microbial degradability of chitosan polymers. Chitosan microspheres containing ondansetron were prepared by emulsion cross linking method. The effect of process variables like chitosan concentration, drug-polymer ratio, emulsifier concentration and stirring speed were studied on particle size and entrapment efficiency of chitosan microspheres. In vitro drug release studies in simulated gastro intestinal fluids showed a burst drug release pattern in the initial hour necessitating microencapsulation around the chitosan microspheres. The optimized formulation was then subjected to microencapsulation with eudragit S-100 by solvent evaporation technique. The effect of different coat/core ratio on particle size, drug entrapment efficiency and in vitro drug release were studied. Formulation which contain 1:10 core/coat ratio released lesser amount of drug in the upper gastro intestinal conditions and so selected as best formulation and then subjected to in vitro drug release studies in presence of rat ceacal contents to assess biodegradability of chitosan microspheres in colon. In order to study the drug release mechanism in vitro drug release data was fitted into various kinetic models. Analysis of regression values suggested that the possible drug release mechanism was Peppas model. PMID:20582191

Jose, S; Dhanya, K; Cinu, T A; Aleykutty, N A

2010-01-01

145

Enhanced bone formation by controlled growth factor delivery from chitosan-based biomaterials  

Microsoft Academic Search

For the purpose of obtaining high bone forming efficacy, development of chitosan was attempted as a tool useful as a scaffolding device. Porous chitosan matrices, chitosan–poly(l-lactide) (PLLA) composite matrices and chitosan coated on PLLA matrices were dealt with in this research. Porous chitosan matrix was fabricated by freeze-drying and cross-linking aqueous chitosan solution. Porous chitosan matrix combined with ceramics and

Jue-Yeon Lee; Sung-Heon Nam; Su-Yeon Im; Yoon-Jeong Park; Yong-Moo Lee; Yang-Jo Seol; Chong-Pyoung Chung; Seung-Jin Lee

2002-01-01

146

Physicochemical characterisation of ?-chitosan from Sepioteuthis lessoniana gladius.  

PubMed

?-Chitin and its chitosan from the gladius of Sepioteuthis lessoniana have been isolated, purified, characterised and compared with the commercial chitosan. Ash, moisture, mineral, metal and elemental content were analyzed using standard techniques. The optical activity of chitin was found to be levorotatory. The degree of deacetylation was calculated by potentiometric titration and (1)H NMR. Viscosity average molecular weight of ?-chitosan was calculated by viscometry and size average molecular weight by GPC. The structure of ?-chitosan was elucidated with FT-IR and NMR. Thermal nature, crystalline structure and morphology of ?-chitosan were characterised through DSC, XRD and SEM, respectively. The water and fat binding capacity of ?-chitosan presently studied was significantly higher than that of the commercial chitosan. The result of the present study adds that S. lessoniana gladius is also an additional source of ?-chitin and chitosan of higher yield, lower molecular weight and higher degree of deacetylation. PMID:23790866

Subhapradha, Namasivayam; Ramasamy, Pasiyappazham; Shanmugam, Vairamani; Madeswaran, Perumal; Srinivasan, Alagiri; Shanmugam, Annaian

2013-04-15

147

Maillard reaction products from chitosan-xylan ionic liquid solution.  

PubMed

A facile method is reported to prepare Maillard reaction products (MRPs) from chitosan and xylan in co-solvent ionic liquid. UV absorbance and fluorescence changes were regarded as indicators of the occurrence of Maillard reaction. FT-IR, NMR, XRD and TG were used to investigate the structure of chitosan-xylan conjugate. The results revealed that when chitosan reacted with xylan in ionic liquid, the hydrogen bonds in chitosan were destroyed, the facts resulted in the formation of chitosan-xylan MRPs. Moreover, when the mass ratio of chitosan to xylan was 1:1, the Maillard reaction proceeded easily. In addition, relatively high antioxidant property was also noted for the chitosan-xylan conjugate with mass ratio 1:1. So the obtained chitosan-xylan MRP is a promising antioxidant agent for food industry. PMID:23987419

Luo, Yuqiong; Ling, Yunzhi; Wang, Xiaoying; Han, Yang; Zeng, Xianjie; Sun, Runcang

2013-06-28

148

Antioxidative activity of chitosans with varying molecular weights  

Microsoft Academic Search

Antioxidant activity of chitosans of different molecular weights (30, 90 and 120kDa chitosan) in salmon (Salmo salar) was investigated. The progress of oxidation was monitored by employing the 2-thiobarbituric acid-reactive substances (TBARS) and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assays. In general, all chitosans exhibited antioxidative activities in salmon. The addition of chitosans to salmon reduced lipid oxidation for seven days of

Kyung W. Kim; R. L. Thomas

2007-01-01

149

Chitosan increases conidiation in fungal pathogens of invertebrates  

Microsoft Academic Search

Antifungal activity of chitosan on plant pathogenic fungi has been widely studied, but little is known about the effect of\\u000a chitosan on fungal biocontrol agents. In this work, we characterize the increase of conidiation induced by chitosan in fungal\\u000a pathogens of invertebrates (FPI). Chitosan increased conidiation of FPI, including Beauveria bassiana, widely used as mycoinsecticide, and did not affect conidia

Javier Palma-Guerrero; Eduardo Larriba; Berenice Güerri-Agulló; Hans-Börje Jansson; Jesus Salinas; Luis Vicente Lopez-Llorca

2010-01-01

150

Supercritical solvent impregnation of ophthalmic drugs on chitosan derivatives  

Microsoft Academic Search

In this work, three chitosan derivatives (N-carboxymethyl chitosan (CMC), N-carboxybutyl chitosan (CBC) and N-succinyl chitosan (SCC)) were impregnated with flurbiprofen (an anti-inflammatory drug) and timolol maleate (an anti-glaucoma drug), using a supercritical solvent impregnation (SSI) technique (and employing high pressure CO2 and CO2+EtOH mixtures) in order to develop hydrogel-type ophthalmic drug delivery applications. Impregnation experiments were carried out from 9.0

Mara E. M. Braga; Maria T. Vaz Pato; Hélio S. R. Costa Silva; Elisabeth I. Ferreira; Maria H. Gil; Catarina M. M. Duarte; Hermínio C. de Sousa

2008-01-01

151

Polyethylene Glycol on Stability of Chitosan Microparticulate Carrier for Protein  

Microsoft Academic Search

Stability enhancement of protein-loaded chitosan microparticles under storage was investigated. Chitosan glutamate at 35 kDa\\u000a and bovine serum albumin as model protein drug were used in this study. The chitosan microparticles were prepared by ionotropic\\u000a gelation, and polyethylene glycol 200 (PEG 200) was applied after the formation of the particles. All chitosan microparticles\\u000a were kept at 25°C for 28 days. A comparison

Manee Luangtana-anan; Sontaya Limmatvapirat; Jurairat Nunthanid; Rapeepun Chalongsuk; Keiji Yamamoto

2010-01-01

152

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

153

Chitosan: effects on wound healing in urogenital tissue: preliminary report.  

PubMed

We conducted a survey of the effect of chitosan on wounds of the genitourinary system in dogs. Wounds were made in the kidney, ureter and penile foreskin. Chitosan caused no adverse effects on urogenital wound healing. A decrease in fibrosis was seen in the wounds treated with chitosan in all tissues studied. These observations suggest that the morbidity of urogenital surgery may be decreased by treating the wounds with chitosan. PMID:3184286

Bartone, F F; Adickes, E D

1988-11-01

154

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.

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

2013-01-01

155

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

PubMed

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

2013-05-21

156

Synthesis and characterization of pH-dependent glycol chitosan and dextran sulfate nanoparticles for effective brain cancer treatment  

Microsoft Academic Search

A novel drug delivery system for the treatment of brain tumors was formulated by methotrexate (MTX)-loaded polymeric nanoparticles (NPs) based on Glycol chitosan (GCS) and Dextran sulfate (DS). The physicochemical properties of resulting particles were investigated, evidencing the contribution of these nanoparticles for brain targeting. In vitro release of MTX was also evaluated. The GCS–DS nanoparticles have been developed based

Mohammad Reza Saboktakin; Roya M. Tabatabaie; Abel Maharramov; Mohammad Ali Ramazanov

2011-01-01

157

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

158

Chitosan coated cotton fiber: preparation and physical properties  

Microsoft Academic Search

A new cotton fiber with a chitosan coating (CCCF) was prepared by the oxidation of a cotton thread with potassium periodate at 60°C in water and subsequent treatment with a solution of chitosan in aqueous acetic acid. Infrared spectra of the CCCF suggested the formation of Schiff's base between the chitosan and the oxidized cellulose. Kjeldahl nitrogen analysis of the

X. D Liu; N Nishi; S Tokura; N Sakairi

2001-01-01

159

New Contact Lens Based on Chitosan\\/Gelatin Composites  

Microsoft Academic Search

A series of chitosan\\/gelatin composite films were prepared by solvent evaporation and characterized for oxygen permeability, optical transmittance, water absorptivity and mechanical properties. The results indicate that the introduction of gelatin was beneficial to increasing water absorption and that oxygen and solute permeability of chitosan composite film was improved. Chitosan\\/gelatin composite films are more permeable, transparent, flexible and biocompatible films

Shi Xin-Yuan; Tan Tian-Wei

2004-01-01

160

Forensic Fingerprint Enhancement using Bioadhesive Chitosan and Gold Nanoparticles  

Microsoft Academic Search

Detection of latent fingerprints using lipophilic and polycationic polymer chitosan has been explored. The gold nanoparticle deposition on chitosan treated latent fingerprints enhances contrast, making the fingerprint identification possible. Chitosan being the second most abundant natural polymer, this technique can be an inexpensive and efficient method for fingerprint enhancement and its subsequent detection. This simple technique has a potential of

Naveed Ul Islam; Kazi F. Ahmed; Abhilash Sugunan; Joydeep Dutta

2007-01-01

161

Core–shell silica@chitosan nanoparticles and hollow chitosan nanospheres using silica nanoparticles as templates: Preparation and ultrasound bubble application  

Microsoft Academic Search

This work reports the preparation of chitosan hollow nanospheres and their uses as the ultrasound-induced imaging agents. Reaction of chitosan to the 4-isocyanato-4?-(3,3-dimethyl-2,4-dioxo-azetidino)diphenylmethane modified silica nanoparticles forms silica@chitosan core shell nanoparticles. Removal of the silica cores with hydrofluoride generates the chitosan hollow nanospheres. Structures and morphology of the silica@chitosan core–shell nanoparticles and chitosan hollow nanospheres are characterized with an X-ray

Ying-Ling Liu; Yen-Hsing Wu; Wei-Bor Tsai; Chih-Chi Tsai; Wen-Shiang Chen; Chuan-Shao Wu

2011-01-01

162

In vitro treatments of Echinococcus granulosus with fungal chitosan, as a novel biomolecule  

PubMed Central

Objective To determined the antiparasitic activity of the isolated chitosan from Penicillium viridicatum, Penicillium aurantiogriseum and commercial chitosan against protoscolicidal of hydatid cysts were determined. Methods After isolating chitosan from fungal cell walls, four concentrations (50, 100, 200, 400 µg/mL) of each type of prepared chitosan and commercial chitosan were used for 10, 30, 60, and 180 min, respectively. Results Among different type of chitosan, commercial chitosan with the highest degree of deacetylation showed high scolicidal activity in vitro. Fungal chitosan could be recommended, as good as commercial chitosan, for hydatic cysts control. Conclusions It seems to be a good alternative to synthetic and chemical scolicidal.

Rahimi-Esboei, Bahman; Fakhar, Mahdi; Chabra, Aroona; Hosseini, Mahboobeh

2013-01-01

163

Antimicrobial effect of water?soluble chitosans with high hydrostatic pressure  

Microsoft Academic Search

Two commercially available water?soluble chitosan salts, chitosan lactate and chitosan hydroglutamate, were examined for antagonistic effect against Escherichia coli V517, Staphylococcus aureus MF?31 and Saccharomyces cerevisiae 15. Significant inactivation of each population was evident within 2 min of incubation with Chitosan. S. cerevisiae was the most sensitive of the microorganisms examined. Concentration effects varied but chitosan hydroglutamate was usually the

Anne M. Papineau; Dallas G. Hoover; Dietrich Knorr; Daniel F. Farkas

1991-01-01

164

Influence of iron oxide nanoparticles on the rheological properties of hybrid chitosan ferrogels  

Microsoft Academic Search

Magnetite nanoparticles have been successfully synthesized in the presence of chitosan using an in situ coprecipitation method in alkali media. This method allows obtaining chitosan ferrogels due to the simultaneous gelation of chitosan. The chitosan concentration has been varied and its effects on the particle synthesis investigated. It has been demonstrated that high chitosan concentrations prevents the formation of magnetite

Rebeca Hernández; Vanessa Zamora-Mora; María Sibaja-Ballestero; José Vega-Baudrit; Daniel López; Carmen Mijangos

2009-01-01

165

Synergistic antimicrobial activities of natural essential oils with chitosan films.  

PubMed

The synergistic antimicrobial activities of three natural essential oils (i.e., clove bud oil, cinnamon oil, and star anise oil) with chitosan films were investigated. Cinnamon oil had the best antimicrobial activity among three oils against Escherichia coli , Staphylococcus aureus , Aspergillus oryzae , and Penicillium digitatum . The chitosan solution exhibited good inhibitory effects on the above bacteria except the fungi, whereas chitosan film had no remarkable antimicrobial activity. The cinnamon oil-chitosan film exhibited a synergetic effect by enhancing the antimicrobial activities of the oil, which might be related to the constant release of the oil. The cinnamon oil-chitosan film had also better antimicrobial activity than the clove bud oil-chitosan film. The results also showed that the compatibility of cinnamon oil with chitosan in film formation was better than that of the clove bud oil with chitosan. However, the incorporated oils modified the mechanical strengths, water vapor transmission rate, moisture content, and solubility of the chitosan film. Furthermore, chemical reaction took place between cinnamon oil and chitosan, whereas phase separation occurred between clove bud oil and chitosan. PMID:22034912

Wang, Lina; Liu, Fei; Jiang, Yanfeng; Chai, Zhi; Li, Pinglan; Cheng, Yongqiang; Jing, Hao; Leng, Xiaojing

2011-11-09

166

Degradation of chitosan-based materials after different sterilization treatments  

NASA Astrophysics Data System (ADS)

Biopolymers have received in recent years an increasing interest for their potential applications in the field of biomedical engineering. Among the natural polymers that have been experimented, chitosan is probably the most promising in view of its exceptional biological properties. Several techniques may be employed to sterilize chitosan-based materials. The aim of our study was to compare the effect of common sterilization treatments on the degradation of chitosan-based materials in various physical states: solutions, hydrogels and solid flakes. Four sterilization methods were compared: gamma irradiation, beta irradiation, exposure to ethylene oxide and saturated water steam sterilization (autoclaving). Exposure to gamma or beta irradiation was shown to induce an important degradation of chitosan, regardless of its physical state. The chemical structure of chitosan flakes was preserved after ethylene oxide sterilization, but this technique has a limited use for materials in the dry state. Saturated water steam sterilization of chitosan solutions led to an important depolymerization. Nevertheless, steam sterilization of chitosan flakes bagged or dispersed in water was found to preserve better the molecular weight of the polymer. Hence, the sterilization of chitosan flakes dispersed in water would represent an alternative step for the preparation of sterilized chitosan solutions. Alternatively, autoclaving chitosan physical hydrogels did not significantly modify the macromolecular structure of the polymer. Thus, this method is one of the most convenient procedures for the sterilization of physical chitosan hydrogels after their preparation.

San Juan, A.; Montembault, A.; Gillet, D.; Say, J. P.; Rouif, S.; Bouet, T.; Royaud, I.; David, L.

2012-02-01

167

Zwitterionic chitosan derivatives for pH-sensitive stealth coating  

PubMed Central

Zwitterionic chitosan, a chitosan derivative with a unique pH-dependent charge profile, was employed to create a stealth coating on the cationic surface of drug carriers. Zwitterionic chitosans were synthesized by amidation of chitosan with succinic anhydride. The succinic anhydride-conjugated chitosan had an isoelectric point, which could be easily tuned from pH 4.9 to 7.1, and showed opposite charges below and above the isoelectric point. The succinic anhydride-conjugated chitosan was able to inhibit the protein adsorption to the cationic surface at physiological pH, compatible with blood components, and well tolerated upon intraperitoneal injection. The succinic anhydride-conjugated chitosan has the potential to serve as a coating material to prevent protein adsorption to cationic surfaces, which can be removed in a pH-responsive manner.

Xu, Peisheng; Bajaj, Gaurav; Shugg, Tyler; Van Alstine, William G.; Yeo, Yoon

2010-01-01

168

Zwitterionic chitosan derivatives for pH-sensitive stealth coating.  

PubMed

Zwitterionic chitosan, a chitosan derivative with a unique pH-dependent charge profile, was employed to create a stealth coating on the cationic surface of drug carriers. Zwitterionic chitosans were synthesized by amidation of chitosan with succinic anhydride. The succinic anhydride-conjugated chitosan had an isoelectric point, which could be easily tuned from pH 4.9 to 7.1 and showed opposite charges below and above the isoelectric point. The succinic anhydride-conjugated chitosan was able to inhibit the protein adsorption to the cationic surface at physiological pH, compatible with blood components and well tolerated upon intraperitoneal injection. The succinic anhydride-conjugated chitosan has the potential to serve as a coating material to prevent protein adsorption to cationic surfaces, which can be removed in a pH-responsive manner. PMID:20695636

Xu, Peisheng; Bajaj, Gaurav; Shugg, Tyler; Van Alstine, William G; Yeo, Yoon

2010-09-13

169

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

2012-06-01

170

Chitosan Fibers Modified with HAp/?-TCP Nanoparticles.  

PubMed

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

2011-10-25

171

Growth rate inhibition of phytopathogenic fungi by characterized chitosans  

PubMed Central

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.

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

2012-01-01

172

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.

Wawro, Dariusz; Pighinelli, Luciano

2011-01-01

173

Chitosanase-based method for RNA isolation from cells transfected with chitosan/siRNA nanocomplexes for real-time RT-PCR in gene silencing  

PubMed Central

Chitosan, a well known natural cationic polysaccharide, has been successfully implemented in vitro and in vivo as a nonviral delivery system for both plasmid DNA and siRNA. While using chitosan/siRNA polyplexes to knock down specific targets, we have underestimated the effect of nucleic acids binding to chitosan when extracting RNA for subsequent quantitative PCR evaluation of silencing. In vitro transfection using chitosan/siRNA-based polyplexes reveals a very poor recovery of total RNA especially when using low cell numbers in 96 well plates. Here, we describe a method that dramatically enhances RNA extraction from chitosan/siRNA-treated cells by using an enzymatic treatment with a type III chitosanase. We show that chitosanase treatment prior to RNA extraction greatly enhances the yield and the integrity of extracted RNA. This method will therefore eliminate the bias associated with lower RNA yield and integrity when quantifying gene silencing of chitosan-based systems using quantitative real time PCR.

Alameh, Mohamad; Jean, Myriam; DeJesus, Diogo; Buschmann, Michael D; Merzouki, Abderrazzak

2010-01-01

174

Quartz Crystal Microbalance Study of Protein Adsorption on Chitosan, Chitosan\\/Poly(vinyl pyrrolidone) Blends and Chitosan-graft-Poly(vinyl pyrrolidone) Surfaces  

Microsoft Academic Search

Adsorption behaviour of bovine serum albumin (BSA) onto chitosan (CS), chitosan\\/poly(vinyl pyrrolidone) blends (CS\\/PVP blends), and chitosan- graft-poly(vinyl pyrrolidone) (CS-graft-PVP) surfaces were investigated using quartz crystal microbalance (QCM). The adsorbed quantities of protein on the three surfaces were examined and were found to decrease in the following order: CS > CS\\/PVP blends > CS-graft-PVP. The kinetics of BSA adsorption in

Xinhua Xu; Chunhuai Zhang; Yumei Zhou; Qiang Liu Juan Cheng; Kangde Yao; Qiang Chen

2007-01-01

175

Plasma surface modification effects on biodegradability and protein adsorption properties of chitosan films  

NASA Astrophysics Data System (ADS)

Plasma-modified chitosan exhibit superior hydrophilicity to that of unmodified one.Plasma-modified chitosan possess enhanced biodegradability than unmodified one.Plasma-modified chitosan exhibit less BSA protein adsorption in BCA protein assays.

Chang, Shih-Hang; Chian, Chin-He

2013-10-01

176

Thermoactivation and dielectric spectroscopy of chitosan films  

NASA Astrophysics Data System (ADS)

The polymer films based on chitosan have been studied using dielectric and thermoactivation spectroscopy. Two relaxation processes have been found in the temperature range 0-150°C: the broad ?-peak in the vicinity of 120°C and the ?-peak in the vicinity of 20°C. The ?-peak can be caused by the presence in the polymer of bound water and/or acetic acid remaining after deacetylation, and the ?-peak, by the activation of the conduction of chitosan. The activation energies of relaxation processes have been calculated.

Bobritskaya, E. I.; Castro, R. A.; Temnov, D. E.

2013-01-01

177

Chitosan biopolymer for fuel cell applications.  

PubMed

Fuel cell is an electrochemical device which converts chemical energy stored in a fuel into electrical energy. Fuel cells have been receiving attention due to its potential applicability as a good alternative power source. Recently, cost-effective and eco-friendly biopolymer chitosan has been extensively studied as a material for membrane electrolytes and electrodes in low to intermediate temperature hydrogen polymer electrolyte fuel cell, direct methanol fuel cell, alkaline fuel cell, and biofuel cell. This paper reviews structure and property of chitosan with respect to its applications in fuel cells. Recent achievements and prospect of its applications have also been included. PMID:23399116

Ma, Jia; Sahai, Yogeshwar

2012-10-26

178

Conjugation of gallic acid onto chitosan: An approach for green and water-based antioxidant  

Microsoft Academic Search

A novel derivative of chitosan, chitosan–gallic acid (chitosan–GA), obtained from a simple conjugating condition with gallic acid using carbodiimide is proposed. The conjugation with gallic acid brings the water-solubility or water swelling property to chitosan. The studies on the free radical scavenging of chitosan–GA clarify its significant antioxidant activity on free radicals, i.e. carbon-centered radicals and hydroxyl radicals. Chitosan–GA clearly

Wanvimol Pasanphan; Suwabun Chirachanchai

2008-01-01

179

Chitosan and chitosan chlorhydrate based various approaches for enhancement of dissolution rate of carvedilol  

PubMed Central

Background and the purpose of the study Carvedilol nonselective ?-adrenoreceptor blocker, chemically (±)-1-(Carbazol-4-yloxy)-3-[[2-(o-methoxypHenoxy) ethyl] amino]-2-propanol, slightly soluble in ethyl ether; and practically insoluble in water, gastric fluid (simulated, TS, pH 1.1), and intestinal fluid (simulated, TS without pancreatin, pH 7.5) Compounds with aqueous solubility less than 1%?W/V often represents dissolution rate limited absorption. There is need to enhance the dissolution rate of carvedilol. The objective of our present investigation was to compare chitosan and chitosan chlorhydrate based various approaches for enhancement of dissolution rate of carvedilol. Methods The different formulations were prepared by different methods like solvent change approach to prepare hydrosols, solvent evaporation technique to form solid dispersions and cogrind mixtures. The prepared formulations were characterized in terms of saturation solubility, drug content, infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), electron microscopy, in vitro dissolution studies and stability studies. Results The practical yield in case of hydrosols was ranged from 59.76 to 92.32%. The drug content was found to uniform among the different batches of hydrosols, cogrind mixture and solid dispersions ranged from 98.24 to 99.89%. There was significant improvement in dissolution rate of carvedilol with chitosan chlorhdyrate as compare to chitosan and explanation to this behavior was found in the differences in the wetting, solubilities and swelling capacity of the chitosan and chitosan salts, chitosan chlorhydrate rapidly wet and dissolve upon its incorporation into the dissolution medium, whereas the chitosan base, less water soluble, would take more time to dissolve. Conclusion This technique is scalable and valuable in manufacturing process in future for enhancement of dissolution of poorly water soluble drugs.

2012-01-01

180

Preparation of alginate\\/chitosan\\/carboxymethyl chitosan complex microcapsules and application in Lactobacillus casei ATCC 393  

Microsoft Academic Search

Lactobacillus casei ATCC 393 was encapsulated with alginate, chitosan and carboxymethyl chitosan by extrusion method and the product could increase the cell numbers of L. casei to be 108cfu\\/g in the dry state after storage at 4°C for 4 weeks. After incubation in simulated gastric (pH 2.0, 2h) and bile juices (1%, 6h), the encapsulated L. casei cell numbers were

Xiao Yan Li; Xi Guang Chen; Zhong Wu Sun; Hyun Jin Park; Dong-Su Cha

2011-01-01

181

Injectable thermosensitive hydrogel based on chitosan and quaternized chitosan and the biomedical properties  

Microsoft Academic Search

A novel injectable thermosensitive hydrogel (CS–HTCC\\/? ?-GP) was successfully designed and prepared using chitosan (CS), quaternized\\u000a chitosan (HTCC) and ?,?-glycerophosphate (?,?-GP) without any additional chemical stimulus. The gelation point of CS–HTCC\\/?\\u000a ?-GP can be set at a temperature close to normal body temperature or other temperature above 25°C. The transition process\\u000a can be controlled by adjusting the weight ratio of

Qiu Xia Ji; Xi Guang Chen; Qing Sheng Zhao; Cheng Sheng Liu; Xiao Jie Cheng; Ling Chong Wang

2009-01-01

182

Macrophage polarization following chitosan implantation.  

PubMed

Macrophages are a key cell in the host response to implants and can be polarized into different phenotypes capable of inducing both detrimental and beneficial outcomes in tissue repair and remodeling, being important in tissue engineering and regenerative medicine. The objective of this study was to evaluate the macrophage response to 3D porous chitosan (Ch) scaffolds with different degrees of acetylation (DA, 5% and 15%). The M1/M2 phenotypic polarization profile of macrophages was investigated in vivo using a rodent air-pouch model. Our results show that the DA affects the macrophage response. Ch scaffolds with DA 5% induced the adhesion of lower numbers of inflammatory cells, being the M2 the predominant phenotypic profile among the adherent macrophages. In the inflammatory exudates F4/80(+)/CD206(+) cells (M2 macrophages) appeared in higher numbers then F4/80(+)/CCR7(+) cells (M1 macrophages), in addition, lower levels of pro-inflammatory cytokines together with higher levels of anti-inflammatory cytokines were found. Ch scaffolds with DA 15% showed opposite results, since M1 were the predominant macrophages both adherent to the scaffold and in the exudates, together with high levels of pro-inflammatory cytokines. In conclusion, Ch scaffolds with DA 5% induced a benign M2 anti-inflammatory macrophage response, whereas Ch scaffolds with DA 15% caused a macrophage M1 pro-inflammatory response. PMID:24074837

Vasconcelos, Daniela P; Fonseca, Ana C; Costa, Madalena; Amaral, Isabel F; Barbosa, Mário A; Aguas, Artur P; Barbosa, Judite N

2013-09-25

183

Factors affecting the composition of oligosaccharides produced in chitosan hydrolysis using immobilized chitosanases.  

PubMed

The hydrolysis reaction of chitosan using immobilized chitosanases with regard to the composition of its products and the yield of the intermediate target products, pentamer and hexamer of chitosan oligosaccharides, was investigated. Chitosanase was immobilized onto agar or agarose gel particles by the multipoint attachment method. In batch experiments, surface enzyme density, support particle size, temperature, agitator speed, and initial substrate concentration significantly affected the composition of the oligosaccharides produced. It was believed that these factors all related to the reaction rate and mass transfer rate at the surface of the support materials immobilizing the enzymes. These effects were summarized as a correlation with Damköhler number (Da), defined as the ratio of the maximum reaction rate to the maximum mass transfer rate. The result showed that the reaction conditions that give a low value of Da provide a high yield of pentamer and hexamer oligosaccharides. PMID:12363347

Kuroiwa, Takashi; Ichikawa, Sosaku; Hiruta, Osamu; Sato, Seigo; Mukataka, Sukekuni

184

Implantable applications of chitin and chitosan  

Microsoft Academic Search

Chitin, extracted primarily from shellfish sources, is a unique biopolymer based on the N-acetyl-glucosamine monomer. More than 40 years have lapsed since this biopolymer had aroused the interest of the scientific community around the world for its potential biomedical applications. Chitin, together with its variants, especially its deacetylated counterpart chitosan, has been shown to be useful as a wound dressing

Eugene Khor; Lee Yong Lim

2003-01-01

185

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

186

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

187

Method for Insolubilizing Enzymes on Chitosan.  

National Technical Information Service (NTIS)

Insolubilized but active enzymes are prepared according to this patent application by mixing an aqueous solution of the enzyme with an aqueous solution of chitosan and then adding a polyfunctional cross-linking agent to form a gel. The so produced gel is ...

M. S. Masri V. G. Randall W. L. Stanley

1976-01-01

188

Permeability evaluation through chitosan membranes using taguchi design.  

PubMed

In the present study, chitosan membranes capable of imitating permeation characteristics of diclofenac diethylamine across animal skin were prepared using cast drying method. The effect of concentration of chitosan, concentration of cross-linking agent (NaTPP), crosslinking time was studied using Taguchi design. Taguchi design ranked concentration of chitosan as the most important factor influencing the permeation parameters of diclofenac diethylamine. The flux of the diclofenac diethylamine solution through optimized chitosan membrane (T9) was found to be comparable to that obtained across rat skin. The mathematical model developed using multilinear regression analysis can be used to formulate chitosan membranes that can mimic the desired permeation characteristics. The developed chitosan membranes can be utilized as a substitute to animal skin for in vitro permeation studies. PMID:21179329

Sharma, Vipin; Marwaha, Rakesh Kumar; Dureja, Harish

2010-10-21

189

Chitosan bio-based organic-inorganic hybrid aerogel microspheres.  

PubMed

Recently, organic-inorganic hybrid materials have attracted tremendous attention thanks to their outstanding properties, their efficiency, versatility and their promising applications in a broad range of areas at the interface of chemistry and biology. This article deals with a new family of surface-reactive organic-inorganic hybrid materials built from chitosan microspheres. The gelation of chitosan (a renewable amino carbohydrate obtained by deacetylation of chitin) by pH inversion affords highly dispersed fibrillar networks shaped as self-standing microspheres. Nanocasting of sol-gel processable monomeric alkoxides inside these natural hydrocolloids and their subsequent CO(2) supercritical drying provide high-surface-area organic-inorganic hybrid materials. Examples including chitosan-SiO(2), chitosan-TiO(2), chitosan-redox-clusters and chitosan-clay-aerogel microspheres are described and discussed on the basis of their textural and structural properties, thermal and chemical stability and their performance in catalysis and adsorption. PMID:22689451

El Kadib, Abdelkrim; Bousmina, Mosto

2012-06-11

190

Synthesis and characterization of chitosan–carbon nanotube composites  

Microsoft Academic Search

Acid functionalized single walled carbon nanotubes were covalently grafted to chitosan by first reacting the oxidized carbon nanotubes with thionyl chloride to form acyl-chlorinated carbon nanotubes which are subsequently dispersed in chitosan and covalently grated to form composite material, CNT–chitosan, 1, which was washed several times to remove un-reacted materials. This composite has been characterized by FTIR, 13C NMR, TGA,

Laura Carson; Cordella Kelly-Brown; Melisa Stewart; Aderemi Oki; Gloria Regisford; Zhiping Luo; Vladimir I. Bakhmutov

2009-01-01

191

Chitosan with phosphonic and carboxylic group: New multidentate ligands  

Microsoft Academic Search

Chemical modifications of polysaccharides are increasingly studied and they have potential providing new applications. N-methylene phosphonic N-methylene carboxylic chitosan was obtained in water soluble form using N-methylene phosphonic chitosan and glyoxylic acid (via aldimine formation) under reduction conditions with sodium borohydride. The modified chitosan was characterized by 1 H NMR, 13 C NMR and FTIR spectroscopy. A practical simple and

Viviana M. Ramos; María Susana Rodríguez; Enrique Agulló; Nora M. Rodríguez; Angeles Heras

2002-01-01

192

Chitosan nanofiber scaffold enhances hepatocyte adhesion and function  

Microsoft Academic Search

To enhance cell attachment and promote liver functions of hepatocytes cultured in bioreactors, a chitosan nanofiber scaffold\\u000a was designed and prepared via electrospinning. Effects of the scaffold on hepatocyte adhesion, viability and function were\\u000a then investigated. Data showed that hepatocytes on chitosan nanofiber scaffold exhibited better viability and tighter cell-substrate\\u000a contact than cells on regular chitosan film. In addition, urea

Xue-Hui Chu; Xiao-Lei Shi; Zhang-Qi Feng; Zhong-Ze Gu; Yi-Tao Ding

2009-01-01

193

DNA biosensor based on chitosan film doped with carbon nanotubes  

Microsoft Academic Search

A biosensor based on chitosan doped with carbon nanotube (CNT) was fabricated to detect salmon sperm DNA. Methylene blue (MB) was employed as a DNA indicator. It was found that CNTs can enhance the electroactive surface area threefold (0.28±0.03 and 0.093±0.06cm2 for chitosan–CNT- and chitosan-modified electrodes, respectively) and can accelerate the rate of electron transfer between the redox-active MB and

Jia Li; Qian Liu; Yingju Liu; Shanchao Liu; Shouzhuo Yao

2005-01-01

194

Hypocholesterolemic action of chitosans with different viscosity in rats  

Microsoft Academic Search

The relationship between hypocholesterolemic efficacy and average molecular weight of chitosan was studied in rats fed a cholesterol-enriched\\u000a (0.5%) diet. Several chitosan preparations with a comparable degree of deacetylation but differing widely in average molecular\\u000a weight, as demonstrated by viscosity, almost completely prevented the rise of serum cholesterol at the 5% dietary level. At\\u000a the 2% level, chitosans with viscosities

Michihiro Sugano; Shuji Watanabea; Akihiro Kishi; Masato Izume; Akira Ohtakara

1988-01-01

195

Properties Evaluation of Sodium Nitrite Treated Chitosan-Cotton Fabric  

Microsoft Academic Search

In this study, chitosan coated-cotton fabric was prepared and then treated with sodium nitrite under mild condition, aiming at the partial removal of surface-chitosan in order to solve the problems of surface dyeing and fabric stiffness. The results showed that sodium nitrite treated chitosan-fabric exhibited an improvement of dyeability (higher dye exhaustion and color strength) when compared to untreated fabric.

Seranee SRISUK; Kawee SRIKULKIT

196

Removal of Phthalate Esters from Aqueous Solutions by Chitosan Bead  

Microsoft Academic Search

Removal of phthalate esters (PAEs) by chitosan bead in aqueous solution was studied. The adsorption isotherms of PAEs by chitosan bead were well described by Freundlich isotherm equations. Results of kinetic experiments indicated that diheptyl phthalate (DHpP) had the highest adsorption capacity (1.52 mg\\/g) among six PAEs in our research. PAE adsorption efficiency by chitosan bead was examined in both

CHIH-YU CHEN; YING-CHIEN CHUNG

2006-01-01

197

Preparation and anticoagulant activity of carboxybutyrylated hydroxyethyl chitosan sulfates  

Microsoft Academic Search

A new method of introduction carboxyl groups to chitosan sulfate by the acylation reaction between hydroxyethyl chitosan sulfates and butane dioic anhydride in homogeneous solution was used to obtain carboxybutyrylated hydroxyethyl chitosan sulfates. The structures of the derivatives were characterized by element analysis, FT-IR, 13C-NMR, and gel permeation chromatography. The content and position of the carboxyl groups could be controlled

Huang Ronghua; Du Yumin; Yang Jianhong

2003-01-01

198

Antioxidant properties of some different molecular weight chitosans.  

PubMed

Chitosan, a cationic polysaccharide, is widely employed as dietary supplement and in pharmacological and biomedical applications. Although numerous studies have focused on its applications as pharmaceutical excipients or bioactive reagents, relationships between molecular weight (Mr) and biological properties remain unclear. The focus of this study was on the antioxidant properties of several Mr chitosans. We measured the ability of seven Mr chitosans (CT1; 2.8 kDa, CT2; 17.0 kDa, CT3; 33.5 kDa, CT4; 62.6 kDa, CT5; 87.7 kDa, CT6; 604 kDa, CT7; 931 kDa) to protect plasma protein from oxidation by peroxyl radicals derived from 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH). A comparison of the antioxidant action of high Mr chitosans (CT6-CT7) with that of low Mr chitosans (CT1-CT5) showed that low Mr chitosans (CT1-CT5) were more effective in preventing the formation of carbonyl groups in plasma protein exposed to peroxyl radicals. AAPH substantially increases plasma protein carbonyl content via the oxidation of human serum albumin (HSA). We also measured the ability of these chitosans to protect HSA against oxidation by AAPH. Low Mr chitosans (CT1-CT5) were found to effectively prevent the formation of carbonyl groups in HSA, when exposed to peroxyl radicals. Low Mr chitosans were also good scavengers of N-centered radicals, but high Mr chitosans were much less effective. We also found a strong correlation between antioxidant activity and the Mr of chitosans in vitro. These activities were also determined by using the 'TPAC' test. These results suggest that low Mr chitosans (CT1-CT3) may be absorbed well from the gastrointestinal tract and inhibit neutrophil activation and oxidation of serum albumin that is frequently observed in patients plasma undergoing hemodialysis, resulting in a reduction in oxidative stress associated with uremia. PMID:19559405

Tomida, Hisao; Fujii, Takeshi; Furutani, Nobuko; Michihara, Akihiro; Yasufuku, Taira; Akasaki, Kenji; Maruyama, Toru; Otagiri, Masaki; Gebicki, Janusz M; Anraku, Makoto

2009-05-13

199

Electrospun chitosan-based nanofibers and their cellular compatibility  

Microsoft Academic Search

Chitosan-based nanofibers with an average fiber diameter controllable from a few microns down to ?40nm and a narrow size distribution were fabricated by electrospinning solutions containing chitosan, polyethylene oxide (PEO), and Triton X-100™. Rheological study showed a strong dependence of spinnability and fiber morphology on solution viscosity and thus on chitosan-to-PEO ratio. The nanofibers can be deposited either as a

Narayan Bhattarai; Dennis Edmondson; Omid Veiseh; Frederick A. Matsen; Miqin Zhang

2005-01-01

200

Effect of chitosan on the growth of human colonic bacteria  

Microsoft Academic Search

Growth of 6 bacterial strains representing dominant members of the human colonic microflora was measured in the presence of\\u000a 0.025, 0.05 and 0.5 % chitosan (from shrimp shells, with a 97 % final degree of deacetylation). The effect of chitosan was\\u000a variable and dependent on bacterial species. The most susceptible to chitosan were bacteria belonging to generaBacteroides andClostridium (91–97% growth

J. Šim?nek; G. Tishchenko; B. Hodrová; H. Barto?ová

2006-01-01

201

Composites based on chitosan- and gold-modified carbon fibers  

Microsoft Academic Search

We report the fabrication of composite materials containing gold particles deposited on the surface of carbon fibers, in particular,\\u000a immobilized in films of chitosan, a natural biopolymer. The fabrication process involves gold-chitosan electrocodeposition\\u000a on unmodified fibers or gold deposition on chitosan-carbon materials used as electrodes. Scanning electron microscopy, energy\\u000a dispersive X-ray analysis, and X-ray diffraction results are used to gain

L. A. Zemskova; A. V. Voit; T. A. Kaidalova; N. N. Barinov

2010-01-01

202

Trimethyl chitosan and its applications in drug delivery  

Microsoft Academic Search

Chitosan, a polymer obtained by deacetylation of chitin is widely studied for its pharmaceutical and nonpharmaceutical applications.\\u000a Recommendations about uses of this polymer although could not be always realized due to limited solubility. Chitosan, for\\u000a example, has been extensively evaluated for its mucoadhesive and absorption enhancement properties. The positive charge on\\u000a the chitosan molecule gained by acidic environment in which

V. K. Mourya; Nazma N. Inamdar

2009-01-01

203

Early events induced by chitosan on plant cells  

Microsoft Academic Search

Chitosan (a polymer of b-1,4-glucosamine residues) is a deacetylated derivative of chitin which presents antifungal properties and acts as a potent elicitor of plant resistance against fungal pathogens. Attention was focused in this study on the chitosan-induced early events in the elicitation chain. Thus, it was shown that chitosan triggered in a dose-dependent manner rapid membrane transient depolarization of Mimosa

Benigne-Ernest Amborabe; Janine Bonmort; Pierrette Fleurat-Lessard; Gabriel Roblin

2008-01-01

204

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

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

1979-01-01

205

Permeabilities of rebamipide via rat intestinal membranes and its colon specific delivery using chitosan capsule as a carrier  

PubMed Central

AIM: To investigate the permeability characteristics of rebamipide across intestinal mucosa, and examine the effects of some absorption enhancers on the permeability across the colonic tissue. Another purpose is to demonstrate the colon-specific delivery of rebamipide with or without absorption enhancers using chitosan capsule as a carrier. METHODS: The permeability of rebamipide was evaluated using an in vitro diffusion chamber system, and the effects of some absorption enhancers on the permeability via colon were further investigated. The release of rebamipide from chitosan or gelatin capsule was studied by Japan Pharmacopoeia rotating basket method. The colonic and plasma concentrations were analyzed by high performance liquid chromatography (HPLC) to evaluate colon-targeting action after oral administration of various dosage forms, and rebamipide with absorption enhancers in chitosan dosage forms. RESULTS: The permeability of rebamipide across the jejunal or ileal membranes was higher than the colonic membranes. Both sodium laurate (C12) and labrasol significantly increased permeability across the colon membranes. On the other hand, the release of rebamipide from chitosan capsule was less than 10% totally within 6 h. The area under concentration-time profile of drug in the colon mucosa using chitosan capsules (AUCLI, 1?6011.2 ng·h/g) was 2.5 times and 4.4 times greater than using gelatin capsules and CMC suspension, respectively. Meanwhile, the area under concentration-time profile of drug in the plasma (AUCPL) was 1016.0 ng·h/mL for chitosan capsule, 1887.9 ng·h/mL for CMC suspension p and 2163.5 ng·h/mL for gelatin capsule. Overall, both AUCLI and AUCPL were increased when C12 was co-administrated, but the increase of AUCLI was much greater; the drug delivery index (DDI) was more than 1 compared with simple chitosan capsule group. CONCLUSION: There was a regional difference in the permeability of Rebamipide across the jejunum, ileum and the colon, and passive diffusion seems to be one of the major transport mechanisms of rebamipide. Absorption enhancers can increase the permeability of rebamipide across the colon tissue significantly. In addition, chitosan capsule may be a useful carrier to deliver rebamipide to the colon specifically and the co-administration of C12 with rebamipide may also be very useful in local treatment.

Huang, Bei-Bei; Li, Guo-Feng; Luo, Jing-Hui; Duan, Lian; Nobuaki, Kishimoto; Akira, Yamamoto

2008-01-01

206

Rapidly photo-cross-linkable chitosan hydrogel for peripheral neurosurgeries.  

PubMed

Restoring continuity to severed peripheral nerves is crucial to regeneration and enables functional recovery. However, the two most common agents for coaptation, sutures and fibrin glues, have drawbacks such as inflammation, pathogenesis, and dehiscence. Chitosan-based adhesives are a promising alternative, reported to have good cytocompatibility and favorable immunogenicity. A photo-cross-linkable hydrogel based on chitosan is proposed as a new adhesive for peripheral nerve anastomosis. Two Az-chitosans were synthesized by conjugating 4-azidobenzoic acid with low (LMW, 15 kDa) and high (HMW, 50-190 kDa) molecular weight chitosans. These solutions formed a hydrogel in less than 1 min under UV light. The LMW Az-chitosan was more tightly cross-linked than the HMW variant, undergoing significantly less swelling and possessing a higher rheological storage modulus, and both Az-chitosan gels were stiffer than commercial fibrin glue. Severed nerves repaired by Az-chitosan adhesives tolerated longitudinal forces comparable or superior to fibrin glue. Adhesive exposure to intact nerves and neural cell culture showed both Az-chitosans to be nontoxic in the acute (minutes) and chronic (days) time frames. These results demonstrate that Az-chitosan hydrogels are cytocompatible and mechanically suitable for use as bioadhesives in peripheral neurosurgeries. PMID:21128673

Rickett, Todd A; Amoozgar, Zohreh; Tuchek, Chad A; Park, Joonyoung; Yeo, Yoon; Shi, Riyi

2010-12-03

207

Removal of copper(II) ions from aqueous solution onto chitosan and cross-linked chitosan beads  

Microsoft Academic Search

The adsorption of Cu(II) ions onto chitosan and cross-linked chitosan beads has been investigated. Chitosan beads were cross-linked with glutaraldehyde (GLA), epichlorohydrin (ECH) and ethylene glycol diglycidyl ether (EGDE) in order to obtain sorbents that are insoluble in aqueous acidic and basic solution. Batch adsorption experiments were carried out as a function of pH, agitation period, agitation rate and concentration

W. S Wan Ngah; C. S Endud; R Mayanar

2002-01-01

208

Application of Ferriferous Oxide Modified by Chitosan in Gene Delivery  

PubMed Central

New approaches to improve the traditional gene carriers are still required. Here we explore Fe3O4 modified with degradable polymers that enhances gene delivery and target delivery using permanent magnetic field. Two magnetic Fe3O4 nanoparticles coated with chitosan (CTS) and polyethylene glycol (PEG) were synthesized by means of controlled chemical coprecipitation. Plasmid pEGFP was encapsulated as a reported gene. The ferriferous oxide complexes were approximately spherical; surface charge of CTS-Fe3O4 and PEG-Fe3O4 was about 20?mv and 0?mv, respectively. The controlled release of DNA from the CTS-Fe3O4 nanoparticles was observed. Concurrently, a desired Fe3O4 concentration of less than 2?mM was verified as safe by means of a cytotoxicity test in vitro. Presence of the permanent magnetic field significantly increased the transfection efficiency. Furthermore, the passive target property and safety of magnetic nanoparticles were also demonstrated in an in vivo test. The novel gene delivery system was proved to be an effective tool required for future target expression and gene therapy in vivo.

Kuang, Yu; Yuan, Tun; Zhang, Zhongwei; Li, Mingyuan; Yang, Yuan

2012-01-01

209

Selective cell recruitment and spatially controlled cell attachment on instructive chitosan surfaces functionalized with antibodies.  

PubMed

Bioactive constructs to guide cellular mobilization and function have been proposed as an approach for a new generation of biomaterials in functional tissue engineering. Adult mesenchymal stem cells have been widely used as a source for cell based therapeutic strategies, namely tissue engineering. This is a heterogeneous cell population containing many subpopulations with distinct regenerative capacity. Thus, one of the issues for the effective clinical use of stem cells in tissue engineering is the isolation of a highly purified, expandable specific subpopulation of stem cells. Antibody functionalized biomaterials could be promising candidates to isolate and recruit specific cell types. Here we propose a new concept of instructive biomaterials that are able to recruit and purify specific cell types from a mixed cell population. This biomimetic concept uses a target-specific chitosan substrate to capture specific adipose derived stem cells. Specific antibodies were covalently immobilized onto chitosan membranes using bis[sulfosuccinimidyl] suberate (BS3). Quartz crystal microbalance (QCM) was used to monitor antibody immobilization/adsorption onto the chitosan films. Specific antibodies covalently immobilized, kept their bioactivity and captured specific cell types from a mixed cell population. Microcontact printing allowed to covalently immobilize antibodies in patterns and simultaneously a spatial control in cell attachment. PMID:23109106

Custódio, C A; Frias, A M; del Campo, A; Reis, R L; Mano, J F

2012-10-30

210

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.

2012-02-01

211

In vitro evaluation of chondroitin sulphate-chitosan microspheres as carrier for the delivery of proteins.  

PubMed

A novel formulation based on chondroitin sulphate/chitosan microspheres (CS/CH) has been investigated for oral delivery of macromolecules using ovalbumin as the model protein (OVA). The microspheres were prepared by a new emulsion-complex coacervation method. Physico-chemical properties of the polymers constituting microparticulate matrix were investigated by IR, DSC, TGA and X-ray diffraction analyses. In vitro tests were performed to evaluate the drug delivery system degradation and the protein release under conditions simulating the intestinal fluids. The ability of colonic enzymes to degrade the microparticulate systems was simulated employing the chondroitinase ABC enzyme. Results showed that the different CS/CH compositions influenced both microparticles stability and the protein release rate. Only the microspheres composed by 1:1 chondroitin sulphate-chitosan ratio achieved an OVA release profile suitable to a possible colon targeting. These microspheres released approximately 30% of ovalbumin encapsulated in 24 h in the different aqueous media tested, while they released 100% of protein in the presence of chondroitinase. The preliminary results demonstrated that chondroitin sulphate-chitosan microspheres can be a suitable delivery system for protein drug envisaged to oral administration. PMID:18855198

Maculotti, Katia; Tira, Enrica M; Sonaggere, Miriam; Perugini, Paola; Conti, Bice; Modena, Tiziana; Pavanetto, Franca

2009-09-01

212

Environmental Application of Chitosan?Supported Catalysts: Catalytic Hollow Fibers for the Degradation of Phenolic Derivatives  

Microsoft Academic Search

Hollow fibers made of chitosan were prepared and tested for the immobilization of palladium, a catalytic metal widely used for reductive reactions. Hollow chitosan fibers were prepared by extrusion of chitosan into a coagulating solution followed by a final conditioning step to increase the stability of chitosan in acidic solutions. The fibers were then contacted with palladium solution at pH

Eric Guibal; Thierry Vincent; Sylvie Spinelli

2005-01-01

213

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

214

Chitosan permeabilizes the plasma membrane and kills cells of Neurospora crassa in an energy dependent manner  

Microsoft Academic Search

Chitosan has been reported to inhibit spore germination and mycelial growth in plant pathogens, but its mode of antifungal action is poorly understood. Following chitosan treatment, we characterized plasma membrane permeabilization, and cell death and lysis in the experimental model, Neurospora crassa. Rhodamine-labeled chitosan was used to show that chitosan is internalized by fungal cells. Cell viability stains and the

J. Palma-Guerrero; I.-C. Huang; H.-B. Jansson; J. Salinas; L. V. Lopez-Llorca; N. D. Read

2009-01-01

215

Antimicrobial activity and physical properties of chitosan–tapioca starch based edible films and coatings  

Microsoft Academic Search

Antimicrobial activity of edible coating solutions based on chitosan and blends of chitosan–tapioca starch with or without potassium sorbate (KS) addition was studied. The agar well diffusion assay showed an antagonist effect on the efficiency of chitosan against Lactobacillus spp. when KS and\\/or tapioca starch were present. A salmon slice coating assay showed that the chitosan solution was the best

María B. Vásconez; Silvia K. Flores; Carmen A. Campos; Juan Alvarado; Lía N. Gerschenson

2009-01-01

216

Biodegradation Study of Microcrystalline Chitosan and Microcrystalline Chitosan/?-TCP Complex Composites  

PubMed Central

Bone repair or regeneration is a common and complicated clinical problem in orthopedic surgery. The importance of natural polymers, such as microcrystalline chitosan, and minerals such as HAp and ?-TCP, has grown significantly over the last two decades due to their renewable and biodegradable source, increasing the knowledge and functionality of composites in technological and biomedical applications. This study compares the biodegradation process, bioactivity, structure, morphology, and mechanical properties of microcrystalline chitosan and microcrystalline chitosan/?-TCP complex; the latter according to the new method of preparation. The complex showed a homogeneous network structure with regular pores, good bioactivity, even after 60 days of conducting the hydrolytic and enzymatic degradation process, showing a bacteriostatic and bactericidal activity. The complex indicates that it could be used successfully as a base for implants and scaffolds production in orthopedic surgery.

Pighinelli, Luciano; Kucharska, Magdalena; Wisniewska-Wrona, Maria; Gruchala, Bogdan; Brzoza-Malczewska, Kinga

2012-01-01

217

Kinetics of coacervation transition versus nanoparticle formation in chitosan–sodium tripolyphosphate solutions  

Microsoft Academic Search

Chitosan (deacetylation=75–85%) and sodium tripolyphosphate (TPP) solutions were observed to undergo spontaneous coacervation transition or nanoparticle formation depending on the chitosan concentration and the volumetric mixing ratio [chitosan\\/TPP]. Three distinct conditions have been identified: (i) [chitosan]?0.5mg\\/ml, 0.5?[chitosan\\/TPP]?2 and pH<5.5, yields spontaneous coacervation, (ii) 0.5?[chitosan]?2.5mg\\/ml, [chitosan\\/TPP]?2 and 3.5chitosan nanoparticles and (iii) 0.5?[chitosan]?3mg\\/ml, 3?[chitosan\\/TPP]?6 and 5

Mandeep Kaloti; H. B. Bohidar

2010-01-01

218

Neuroprotective Properties of Chitosan and Its Derivatives  

PubMed Central

Neuronal cells are extremely vulnerable and have a limited capacity for self-repair in response to injury. For those reasons, there is obvious interest in limiting neuronal damage. Mechanisms and strategies used in order to protect against neuronal injury, apoptosis, dysfunction, and degeneration in the central nervous system are recognized as neuroprotection. Neuroprotection could be achieved through several classes of natural and synthetic neuroprotective agents. However, considering the side effects of synthetic neuroprotective agents, the search for natural neuroprotective agents has received great attention. Recently, an increasing number of studies have identified neuroprotective properties of chitosan and its derivatives; however, there are some significant challenges that must be overcome for the success of this approach. Hence, the objective of this review is to discuss neuroprotective properties of chitosan and its derivatives.

Pangestuti, Ratih; Kim, Se-Kwon

2010-01-01

219

Chitosan electrodeposition for microrobotic drug delivery.  

PubMed

A method to functionalize steerable magnetic microdevices through the co-electrodeposition of drug loaded chitosan hydrogels is presented. The characteristics of the polymer matrix have been investigated in terms of fabrication, morphology, drug release and response to different environmental conditions. Modifications of the matrix behavior could be achieved by simple chemical post processing. The system is able to load and deliver 40-80 ?g cm(-2) of a model drug (Brilliant Green) in a sustained manner with different profiles. Chitosan allows a pH responsive behavior with faster and more efficient release under slightly acidic conditions as can be present in tumor or inflamed tissue. A prototype of a microrobot functionalized with the hydrogel is presented and proposed for the treatment of posterior eye diseases. PMID:23355508

Fusco, Stefano; Chatzipirpiridis, George; Sivaraman, Kartik M; Ergeneman, Olgaç; Nelson, Bradley J; Pané, Salvador

2013-01-25

220

Immobilization of 5-fluorouridine on chitosan.  

PubMed

The 2',3'-O-levulinic acid derivative 2b of the cancerostatic 5-fluorouridine as well as its N(3)-farnesylated nucleolipid 2d were synthesized and coupled to H2 O-soluble chitosanes of different molecular weight and at various pH values (3.5-5.5) leading to 6 and 7. In addition, the coumarine fluorophore ATTO-488 N(9)-butanoate was bound to the biopolymer by a sequential-coupling technique to afford 9 and 10. Moreover, chitosan foils were prepared, to which 2b was coupled. Their degradation by chitosanase (from Streptomyces sp. N174) was studied UV-spectrophotometrically in a Franz diffusion cell. PMID:24130026

Malecki, Edith; Viere, Rebecca; Rosemeyer, Helmut

2013-10-01

221

Food applications of chitin and chitosans  

Microsoft Academic Search

Chitin is the second most abundant natural biopolymer after cellulose. The chemical structure of chitin is similar to that of cellulose with 2-acetamido-2-deoxy-?-d-glucose (NAG) monomers attached via ?(1?4) linkages. Chitosan is the deacetylated (to varying degrees) form of chitin, which, unlike chitin, is soluble in acidic solutions. Application of chitinous products in foods and pharmaceuticals as well as processing aids

Fereidoon Shahidi; Janak Kamil Vidana Arachchi; You-Jin Jeon

1999-01-01

222

Sorption of malachite green on chitosan bead  

Microsoft Academic Search

Chitosan bead was synthesized for the removal of a cationic dye malachite green (MG) from aqueous solution. The effects of temperature (303, 313 and 323K), pH of the solution (2–11) on MG removal was investigated. Preliminary kinetic experiment was carried out up to 480min. The sorption equilibrium was reached within 5h (300min). In order to determine the adsorption capacity, the

Zehra Bekçi; Co?an Özveri; Yolda? Seki; Kadir Yurdakoç

2008-01-01

223

Development of chitosan-nanoparticle film based materials for controlled quality of minced beef during refrigerated storage  

Microsoft Academic Search

Chitosan nanoparticles were prepared based on the ionic gelation of chitosan with tripolyphosphate anions. The physicochemical properties of the chitosan nanoparticles were determined by FTIR analysis, XRD pattern and TEM. The effects of chitosan nanoparticles treatment on the shelf-life extension of minced beef stored at 20+\\/-1° C were studied, including chemical and microbiological,. Results indicated that chitosan nanoparticle treatment reduced

2010-01-01

224

Mucoadhesive 4-carboxybenzenesulfonamide-chitosan with antibacterial properties.  

PubMed

The mucoadhesive property of chitosan, especially in an acidic (chitosan. Four different feeding ratios of 4-carboxybenzensulfonamide (4-CBS) to chitosan in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride as a coupling agent were investigated. The 0.2:1 (w/w) ratio 4-CBS:chitosan revealed a 20-fold stronger mucoadhesion to mucin type II than the native chitosan in the simulated gastric fluid (SGF; pH 1.2), and a swelling ratio after 1 h in water, SGF and simulated intestinal fluid (pH 7.4) of about 2.9-, 3.0- and 3.4-fold higher than that of chitosan, respectively. In tissue culture, the 4-CBS-chitosan, like chitosan, were found to be non-cytotoxic to the Vero, KB, MCF-7 and NCI-H187 cell lines but showed potential antibacterial activity against Escherichia coli and Staphlyococcus aureus as model gram-negative and gram-positive bacteria, respectively. PMID:23544535

Suvannasara, Phruetchika; Juntapram, Kotchakorn; Praphairaksit, Nalena; Siralertmukul, Krisana; Muangsin, Nongnuj

2013-01-24

225

Synthesis and characterization of oil-chitosan composite spheres.  

PubMed

Oil-chitosan composite spheres were synthesized by encapsulation of sunflower seed oil in chitosan droplets, dropping into NaOH solution and in situ solidification. Hydrophilic materials (i.e., iron oxide nanoparticles) and lipophilic materials (i.e., rhodamine B or epirubicin) could be encapsulated simultaneously in the spheres in a one step process. The diameters of the prepared spheres were 2.48 ± 0.11 mm (pure chitosan spheres), 2.31 ± 0.08 mm (oil-chitosan composites), 1.49 ± 0.15 mm (iron-oxide embedded oil-chitosan composites), and 1.69 ± 0.1 mm (epirubicin and iron oxide encapsulated oil-chitosan composites), respectively. Due to their superparamagnetic properties, the iron-oxide embedded oil-chitosan composites could be guided by a magnet. A lipophilic drug (epirubicin) could be loaded in the spheres with encapsulation rate measured to be 72.25%. The lipophilic fluorescent dye rhodamine B was also loadable in the spheres with red fluorescence being observed under a fluorescence microscope. We have developed a novel approach to an in situ process for fabricating oil-chitosan composite spheres with dual encapsulation properties, which are potential multifunctional drug carriers. PMID:23681059

Huang, Keng-Shiang; Wang, Chih-Yu; Yang, Chih-Hui; Grumezescu, Alexandru Mihai; Lin, Yung-Sheng; Kung, Chao-Pin; Lin, I-Yin; Chang, Yi-Ching; Weng, Wei-Jie; Wang, Wei-Ting

2013-05-16

226

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

227

Metal complexation by chitosan and its derivatives: a review  

Microsoft Academic Search

One of the major applications of chitosan and its many derivatives is based on its ability to bind strongly heavy and toxic metal ions. This article reviews the various classes of chitosan derivatives and compares their ion binding abilities under varying conditions, as well as the analytical methods to analyze them, the sorption mechanism, and structural analysis of the metal

A. J Varma; S. V Deshpande; J. F Kennedy

2004-01-01

228

The role of cellulosics in chitosan flocculation of Zymomonas mobilis  

Microsoft Academic Search

The flocs produced by an autoflocculent strain of Zymomonas mobilis are easily disrupted by gentle agitation. Treatment of a disrupted cell suspension with the flocculant chitosan yields less easily disrupted floes. The effectiveness of chitosan is attributed to the hydrogen bonding of the flocculant with the cell-bound and free cellulosic materials which facilitate polymer bridging and an electrostatic interaction between

J. HughesI; D. K. Ramsden; J. M. Bouibyz

1994-01-01

229

Antibacterial characteristics and activity of acid-soluble chitosan  

Microsoft Academic Search

The antibacterial activity of chitosan was investigated by assessing the mortality rates of Escherichia coli and Staphylococcus aureus based on the extent of damaged or missing cell walls and the degree of leakage of enzymes and nucleotides from different cellular locations. Chitosan was found to react with both the cell wall and the cell membrane, but not simultaneously, indicating that

Ying-Chien Chung; Chih-Yu Chen

2008-01-01

230

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

2013-06-20

231

ECM-Chitosan Bandage for Tissue Repair  

NASA Astrophysics Data System (ADS)

Extracellular matrices (ECMs) are currently applied in reconstructive surgery to enhance wound healing and tissue remodelling. Sutures and staples are usually employed to stabilize ECM on tissue although they may damage the matrix structure. In this investigation, a novel biocompatible bandage was developed to implant ECM on tissue without sutures. An adhesive film, based on chitosan, was integrated with small intestine submucosa (SIS) in a single bandage strip. This bandage was bonded to sheep small intestine upon laser irradiation of the chitosan film (P = 0.12 W, Fluence = 46+/-1 J/cm2) to assess tissue adhesion strength. Thermocouples were used to estimate temperatures under SIS during laser irradiation. The bandage successfully bonded to intestine achieving a shear stress of 9.6+/-1.6 kPa(n = 15). During laser irradiation, the temperature increased modestly to 31+/-2 0C(n = 14) beneath the ECM portion of the bandage. The SIS-chitosan bandage bonded effectively to tissue without sutures and preserved the ECM structure avoiding irreversible thermal denaturation of imbedded bioactive proteins.

Lauto, Antonio; Longo, Leonardo

2010-05-01

232

Preparation and important functional properties of water-soluble chitosan produced through Maillard reaction  

Microsoft Academic Search

The objective of this research was to improve the solubility of chitosan at neutral or basic pH using the Maillard-type reaction method. To prepare the water-soluble chitosans, various chitosans and saccharides were used under various operating conditions. Biological and physicochemical properties of the chitosan-saccharide derivatives were investigated as well. Results indicated that the solubility of modified chitosan is significantly greater

Ying-Chien Chung; Cheng-Lang Kuo; Chiing-Chang Chen

2005-01-01

233

Strain-hardening effect of graphene on a chitosan chain for the tissue engineering  

NASA Astrophysics Data System (ADS)

We report the results of the chitosan dimer study, the mechanism of its interaction with the carbon nanostructures and also the mechanical properties of the chitosan/graphene, chitosan/nanotube complexes using the density function and the molecular dynamic methods. It was established that the physical adsorption of the chitosan with graphene is carried out by the Van der Waals interaction between the hexagonal links of the chitosan with the hexagonal cell of the atomic grid of graphene and nanotube.

Glukhova, O. E.; Kirillova, I. V.; Kolesnikova, A. S.; Kossovich, E. L.; Ten, G. N.

2012-02-01

234

Carbon nanotube–chitosan modified disposable pencil graphite electrode for Vitamin B 12 analysis  

Microsoft Academic Search

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 B12. 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

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

2011-01-01

235

Preparation, characterization, and antioxidant properties of gallic acid- grafted-chitosans  

Microsoft Academic Search

Gallic acid-grafted-chitosans (GA-g-chitosans) with four different grafting ratios were prepared by a free radical-induced grafting reaction in order to improve antioxidant and water-solubility. To verify the synthesis of GA-g-chitosans, 1H NMR and thin layer chromatography were employed, and the results revealed that GA was grafted onto the chitosan. The antioxidant properties of the GA-g-chitosans were evaluated using several in vitro

Young-Sook Cho; Se-Kwon Kim; Chang-Bum Ahn; Jae-Young Je

2011-01-01

236

Alternating bioactivity of multilayer thin films assembled from charged derivatives of chitosan  

Microsoft Academic Search

Charged derivatives of chitosan, N-sulfofurfuryl chitosan (SFC) and N-[(2-hydroxyl-3-trimethylammonium)propyl]chitosan chloride (HTACC) were prepared by reductive alkylation of amino groups of chitosan (CHI) using 5-formyl-2-furansulfonic acid, sodium salt (FFSA) as a reagent and ring opening of glycidyltrimethylammonium chloride (GTMAC) by amino groups of chitosan, respectively. The chemical structures of the charged derivatives were verified by 1H NMR and FTIR analyses. Multilayer

Somruethai Channasanon; Wilaiporn Graisuwan; Suda Kiatkamjornwong; Voravee P. Hoven

2007-01-01

237

Microwave–Assisted Synthesis of Quaternized Carboxymethyl Chitosan in Aqueous Solution and its Thermal Behavior  

Microsoft Academic Search

A novel promising polyampholyte, being water–soluble quaternized carboxymethyl chitosan (QCM–chitosan), can be prepared by grafting carboxymethyl groups and quaternary ammonium groups on chitosan. Traditionally, QCM–chitosan was obtained by a conventional heating method in organic solvent for a lengthy time. The present study was to prepare QCM–chitosan rapidly under microwave irradiation for 70 min; the whole preparation proceeded in water without

Bo Liu; Xiaoying Wang; Bin Yang; Runcang Sun

2012-01-01

238

Design and development of hydrogel beads for targeted drug delivery to the colon  

Microsoft Academic Search

The purpose of this research was to develop and evaluate a multiparticulate system of chitosan hydrogel beads exploiting pH-sensitive\\u000a property and specific biodegradability for colon-targeted delivery of satranidazole. Chitosan hydrogel beads were prepared\\u000a by the cross-linking method followed by enteric coating with Eudragit S100. All formulations were evaluated for particle size,\\u000a encapsulation efficiency, swellability, and in vitro drug release. The

Sanjay K. Jain; Anekant Jain; Yashwant Gupta; Manisha Ahirwar

2007-01-01

239

Plasma Depolymerization of Chitosan in the Presence of Hydrogen Peroxide  

PubMed Central

The depolymerization of chitosan by plasma in the presence of hydrogen peroxide (H2O2) was investigated. The efficiency of the depolymerization was demonstrated by means of determination of viscosity-average molecular weight and gel permeation chromatography (GPC). The structure of the depolymerized chitosan was characterized by Fourier-transform infrared spectra (FT-IR), ultraviolet spectra (UV) and X-ray diffraction (XRD). The results showed that chitosan can be effectively degradated by plasma in the presence of H2O2. The chemical structure of the depolymerized chitosan was not obviously modified. The combined plasma/H2O2 method is significantly efficient for scale-up manufacturing of low molecular weight chitosan.

Ma, Fengming; Wang, Zhenyu; Zhao, Haitian; Tian, Shuangqi

2012-01-01

240

Chitosan as a barrier membrane material in periodontal tissue regeneration.  

PubMed

Periodontal regeneration is defined as regeneration of the tooth-supporting tissues including cementum, periodontal ligament, and alveolar bone. Guided tissue regeneration (GTR) has been demonstrated to be an effective technique to achieve periodontal regeneration. In the GTR procedures, various kinds of membranes play important roles. Chitosan, a deacetylated derivative of chitin, is biocompatible, biodegradable, and antimicrobial. It acts as hydrating agent and possesses tissue healing and osteoinducing effect. Chitosan can be easily processed into membranes, gels, nanofibers, beads, nanoparticles, scaffolds, and sponges forms and can be used in drug delivery systems. Here, we review the bioproperties of chitosan and report the progress of application of chitosan as membranes in GTR and guided bone regeneration (GBR), which indicates that chitosan could be a good substrate candidate as the materials for the GTR/GBR membranes. PMID:22287502

Xu, Chun; Lei, Chang; Meng, Liuyan; Wang, Changning; Song, Yaling

2012-01-28

241

Synthesis and characterization of chitosan-carbon nanotube composites.  

PubMed

Acid functionalized single walled carbon nanotubes were covalently grafted to chitosan by first reacting the oxidized carbon nanotubes with thionyl chloride to form acyl-chlorinated carbon nanotubes which are subsequently dispersed in chitosan and covalently grated to form composite material, CNT-chitosan, 1, which was washed several times to remove un-reacted materials. This composite has been characterized by FTIR, 13C NMR, TGA, SEM and TEM and has been shown to exhibit enhanced thermal stability. The reaction of 1, with poly lactic acid has also been accomplished to yield CNTchitosan-g-poly(LA), 2 and fully characterized by the above techniques. Results showed covalent attachment of chitosan and chitosan-poly lactic acid to the carbon nanotubes. PMID:20200591

Carson, Laura; Kelly-Brown, Cordella; Stewart, Melisa; Oki, Aderemi; Regisford, Gloria; Luo, Zhiping; Bakhmutov, Vladimir I

2009-03-15

242

Chitosan nanofiber scaffold enhances hepatocyte adhesion and function.  

PubMed

To enhance cell attachment and promote liver functions of hepatocytes cultured in bioreactors, a chitosan nanofiber scaffold was designed and prepared via electrospinning. Effects of the scaffold on hepatocyte adhesion, viability and function were then investigated. Data showed that hepatocytes on chitosan nanofiber scaffold exhibited better viability and tighter cell-substrate contact than cells on regular chitosan film. In addition, urea synthesis, albumin secretion and cytochrome P450 activity of hepatocytes on chitosan nanofiber scaffold were all 1.5 to 2 folds higher than the controls. Glycogen synthesis was also increased as compared with the controls. These results suggested the potential application of this chitosan nanofiber scaffold as a suitable substratum for hepatocyte culturing in bioreactors. PMID:19037598

Chu, Xue-Hui; Shi, Xiao-Lei; Feng, Zhang-Qi; Gu, Zhong-Ze; Ding, Yi-Tao

2008-11-27

243

Advances in chitosan-based drug delivery vehicles  

NASA Astrophysics Data System (ADS)

Within the past few years, chitosan-based drug delivery vehicles have become some of the most attractive to be studied. In contrast to all other polysaccharides, chitosan has demonstrated its unique characteristics for drug delivery platforms, including its active primary amino groups for chemical modification, simple and mild preparation methods for the encapsulation of biomolecules or drugs, mucoadhesion to facilitate transport across mucosal barriers and so on. In this review, an overview of the various types of chitosan-based drug delivery systems is provided, with special focus on polymeric drug conjugates and drug nanocarriers. The first part of the review is concerned with the development and applications of polymeric chitosan-drug conjugates. Then the chitosan-based nanocarrier systems as well as their preparation methods and applications are further discussed.

Hu, Liming; Sun, Yun; Wu, Yan

2013-03-01

244

Chitosan-based hydrogels for controlled, localized drug delivery.  

PubMed

Hydrogels are high-water content materials prepared from cross-linked polymers that are able to provide sustained, local delivery of a variety of therapeutic agents. Use of the natural polymer, chitosan, as the scaffold material in hydrogels has been highly pursued thanks to the polymer's biocompatibility, low toxicity, and biodegradability. The advanced development of chitosan hydrogels has led to new drug delivery systems that release their payloads under varying environmental stimuli. In addition, thermosensitive hydrogel variants have been developed to form a chitosan hydrogel in situ, precluding the need for surgical implantation. The development of these intelligent drug delivery devices requires a foundation in the chemical and physical characteristics of chitosan-based hydrogels, as well as the therapeutics to be delivered. In this review, we investigate the newest developments in chitosan hydrogel preparation and define the design parameters in the development of physically and chemically cross-linked hydrogels. PMID:19799949

Bhattarai, Narayan; Gunn, Jonathan; Zhang, Miqin

2009-09-30

245

Nitrate and phosphate removal by chitosan immobilized Scenedesmus.  

PubMed

The effect of chitosan immobilization of Scenedesmus spp. cells on its viability, growth and nitrate and phosphate uptake was investigated. Scenedesmus sp. (strains 1 and 2) and Scenedesmus obliquus immobilized in chitosan beads showed high viability after the immobilization process. Immobilized Scenedesmus sp. strain 1 had a higher growth rate than its free living counterpart. Nitrate and phosphate uptake by immobilized cells of Scenedesmus sp. (strain 1), freely suspended cells and blank chitosan beads (without cells) were evaluated. Immobilized cells accomplished a 70% nitrate and 94% phosphate removal within 12h of incubation while free-living cells removed 20% nitrate and 30% phosphate within 36 h of treatment. Blank chitosan beads were responsible for up to 20% nitrate and 60% phosphate uptake at the end of the experiment. Chitosan is a suitable matrix for immobilization of microalgae, particularly Scenedesmus sp., but this system should be improved before its application for water quality control. PMID:17531478

Fierro, Sashenka; Sánchez-Saavedra, Maria del Pilar; Copalcúa, Carmen

2007-05-24

246

Chitosan-coated polystyrene microplate for covalent immobilization of enzyme.  

PubMed

Microplates made of polystyrene have been widely used for immunoassays. Protein molecules that have been immobilized on a hydrophobic polystyrene microplate by passive adsorption lose their activity and suffer considerable denaturation. A new chitosan-coated microplate suitable for the covalent immobilization of enzymes has been developed. The primary amino groups of chitosan were exploited for this covalent coupling of proteins. The optical transmittance of the chitosan-coated microplate, at wavelengths of 400-800 nm, was estimated to be suitable for its application in chromogenic reaction-based bioassays. The immobilization efficiency of the chitosan-coated microplate was demonstrated to be far superior to that of a conventional microplate when tested using acetylcholinesterase (AChE) and ?-glucosidase as model biomolecules, and the chitosan-coated microplate may thus have potential applications in biosensing and bioreactor systems. PMID:21842444

Zhang, Yaodong; Li, Li; Yu, Caihong; Hei, Tingting

2011-08-14

247

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

248

BSA and fibrinogen adsorption on chitosan/?-carrageenan polyelectrolyte complexes.  

PubMed

PECs of chitosan/?-carrageenan are prepared in three different volumetric rations. The complex formation is characterized in order to evaluate the blending formation. Blood compatibility is evaluated by protein adsorption (BSA and fibrinogen) and PEC toxicities are determined with fibroblast cell viability and proliferation. The swelling degree of PECs decreases when the amount of chitosan increases. Due to the linked film formation, PECs decrease BSA adsorption and increase fibrinogen adsorption when compared to the pristine chitosan and ?-carrageenan films. Although pristine chitosan and ?-carrageenan films produced similar cell expansion and viability, the PEC 50:50 vol% chitosan/?-carrageenan PEC may be acceptable as a new scaffold for cell therapies, due to their effect on cell survival. PMID:23765589

Carneiro, Thiane N; Novaes, Denise S; Rabelo, Rodrigo B; Celebi, Betul; Chevallier, Pascale; Mantovani, Diego; Beppu, Marisa M; Vieira, Rodrigo S

2013-06-14

249

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

2010-12-29

250

Neural Stem Cell Affinity of Chitosan and Feasibility of Chitosan-Based Porous Conduits as Scaffolds for Nerve Tissue Engineering  

Microsoft Academic Search

Neural stem cells (NSCs) are currently considered as powerful candidate seeding cells for regeneration of both spinal cords and peripheral nerves. In this study, NSCs derived from fetal rat cortices were co-cultured with chitosan to evaluate the cell affinity of this material. The results showed that NSCs grew and proliferated well on chitosan films and most of them differentiated into

Aijun Wang; Qiang Ao; Qing He; Xiaoming Gong; Kai Gong; Yandao Gong; Nanming Zhao; Xiufang Zhang

2006-01-01

251

Effect of chitosan type on protein and water recovery efficiency from surimi wash water treated with chitosan–alginate complexes  

Microsoft Academic Search

Previous research has shown that soluble protein recovery by chitosan (Chi) complexes with polyanions such as alginate (Alg) is more effective than using chitosan alone. In this study, Chi–Alg complexes were used to recover soluble proteins from surimi wash water (SWW) slightly acidified to pH 6. Six Chi samples differing in molecular weight (MW) and degree of deacetylation (DD) were

Singgih Wibowo; Gonzalo Velazquez; Vivek Savant; J. Antonio Torres

2007-01-01

252

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

253

Effectiveness of chitosan on the inactivation of enteric viral surrogates.  

PubMed

Chitosan is known to have bactericidal and antifungal activity. Although human noroviruses are the leading cause of non-bacterial gastroenteritis, information on the efficacy of chitosan against foodborne viruses is very limited. The objective of this work was to determine the effectiveness of different molecular weight chitosans against the cultivable human norovirus and enteric virus surrogates, feline calicivirus, FCV-F9, murine norovirus, MNV-1, and bacteriophages, MS2 and phiX174. Five purified chitosans (53, 222, 307, 421, ~1150 kDa) were dissolved in water, 1% acetic acid, or aqueous HCl pH = 4.3, sterilized by membrane filtration, and mixed with equal volume of virus to obtain a final concentration of 0.7% chitosan and 5 log(10) PFU/ml virus. Virus-chitosan suspensions were incubated for 3 h at 37 °C. Untreated viruses in PBS, in PBS with acetic acid, and in PBS with HCl were tested as controls. Each experiment was run in duplicate and replicated at least twice. Water-soluble chitosan (53 kDa) reduced phiX174, MS2, FCV-F9 and MNV-1 titers by 0.59, 2.44, 3.36, and 0.34 log(10) PFU/ml respectively. Chitosans in acetic acid decreased phiX174 by 1.19-1.29, MS2 by 1.88-5.37, FCV-F9 by 2.27-2.94, and MNV-1 by 0.09-0.28 log(10) PFU/ml, respectively. Increasing the MW of chitosan corresponded with an increasing antiviral effect on MS2, but did not appear to play a role for the other three tested viral surrogates. Overall, chitosan treatments showed the greatest reduction for FCV-F9, and MS2 followed by phiX174, and with no significant effect on MNV-1. PMID:22850374

Davis, Robert; Zivanovic, Svetlana; D'Souza, Doris H; Davidson, P Michael

2012-04-28

254

A New Strategy Based on Smrho Protein Loaded Chitosan Nanoparticles as a Candidate Oral Vaccine against Schistosomiasis  

PubMed Central

Background Schistosomiasis is one of the most important neglected tropical diseases and an effective control is unlikely in the absence of improved sanitation and vaccination. A new approach of oral vaccination with alginate coated chitosan nanoparticles appears interesting because their great stability and the ease of target accessibility, besides of chitosan and alginate immunostimulatory properties. Here we propose a candidate vaccine based on the combination of chitosan-based nanoparticles containing the antigen SmRho and coated with sodium alginate. Methods and Findings Our results showed an efficient performance of protein loading of nanoparticles before and after coating with alginate. Characterization of the resulting nanoparticles reported a size around 430 nm and a negative zeta potential. In vitro release studies of protein showed great stability of coated nanoparticles in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). Further in vivo studies was performed with different formulations of chitosan nanoparticles and it showed that oral immunization was not able to induce high levels of antibodies, otherwise intramuscular immunization induced high levels of both subtypes IgG1 and IgG2a SmRho specific antibodies. Mice immunized with nanoparticles associated to CpG showed significant modulation of granuloma reaction. Mice from all groups immunized orally with nanoparticles presented significant levels of protection against infection challenge with S. mansoni worms, suggesting an important role of chitosan in inducing a protective immune response. Finally, mice immunized with nanoparticles associated with the antigen SmRho plus CpG had 38% of the granuloma area reduced and also presented 48% of protection against of S. mansoni infection. Conclusions Taken together, this results support this new strategy as an efficient delivery system and a potential vaccine against schistosomiasis.

Oliveira, Carolina R.; Rezende, Cintia M. F.; Silva, Marina R.; Pego, Ana Paula; Borges, Olga; Goes, Alfredo M.

2012-01-01

255

Feasibility study of a gadolinium-loaded DIN-based liquid scintillator  

NASA Astrophysics Data System (ADS)

DIN (di-isopropylnaphthalene) has a high flashpoint and can be used as a base solvent in liquid scintillators. It reduces safety concerns to humans and the environment. (PPO, 3 g/ ?) and (bis-MSB, 30 mg/ ?) were dissolved to formulate a DIN-based liquid scintillator (LS). A gadolinium (Gd) complex with carboxylic acid was synthesized using a neutralized chemical reaction. Then, 0.1% Gd was loaded into the LS. This Gd-loaded DIN-based LS using a solvent-solvent extraction method is the first attempt at a LS. In this study, we investigated the physical and the optical properties of this LS, and we will summarize all the characteristics of the Gd-loaded DIN-based LS.

Song, Sook Hyung; Joo, Kyung Kwang; So, Sun Heang; Yeo, In Sung

2013-09-01

256

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

257

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 deploymerization 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

2013-09-09

258

Preparation and function of composite asymmetric chitosan/CM-chitosan membrane.  

PubMed

A novel composite asymmetric chitosan/CM-chitosan membrane (C-P-C) was prepared, the top-layer was chitosan (CS), the intermediate was PVA, and the substrate was carboxymethyl chitosan (CM-CS). C-P-C membrane had capability in mechanical strength, light transparence, vapor permeability, and wound skin joining. The CS and CM-CS in C-P-C membrane were selected by series independent experiments, respectively. CS (MW 90,000 Da) had the highest antibacterial activity for E.coli. CM-CS had biocompatibility, no cytotoxicity, and had the activity of promoting growth of human skin fibroblast and inhibiting the growth of keloid fibroblast. The normal skin fibroblast can growth on the CM-CS surface of C-P-C, and have no conglomeration in higher cell density, and the keloid fibroblast could not growth on CM-CS surface of C-P-C. The animal experiment demonstrated that wound, covered with the C-P-C membrane, was hemostatic, healing quickly and had histocompatibility. The results indicated that the C-P-C membrane could be used as dressing of skin repair, and had the potential in promoting wound healing and inhibiting the keloid formation. PMID:17914636

Pang, Hong Tao; Chen, Xi Guang; Ji, Qiu Xia; Zhong, De Yu

2007-10-04

259

A biomimetic chitosan composite with improved mechanical properties in wet conditions.  

PubMed

Chitosan is one of the most widely used structural polymers for biomedical applications because it has many favorable properties. However, one of the most critical drawbacks regarding the use of chitosan as a biomedical material is its poor mechanical properties in wet conditions. Here, we designed a method to improve the mechanical properties of chitosan in wet conditions and minimized the swelling behavior of chitosan film due to water adsorption by mimicking the sclerotization of insect cuticles and squid beaks, that is, catechol-meditated crosslinking. The biomimetic chitosan composite film was prepared by mixing chitosan with L-3,4-dihydroxyphenylalanine (DOPA) as a catecholic crosslinker and sodium periodate as an oxidant. The catechol-meditated crosslinking provided a sevenfold enhancement in the stiffness in wet conditions compared to pure chitosan films and reduced the swelling behavior of the chitosan film. This strategy expands the possible applications for the use of chitosan composites as load-bearing biomaterials. PMID:23319264

Oh, Dongyeop X; Hwang, Dong Soo

2013-03-06

260

Cell mimetic monolayer supported chitosan-haemocompatibility studies.  

PubMed

Chitosan is a natural polymer, widely explored for biomedical and tissue engineering applications. However the thrombogenic nature limits their application in blood contacting devices and implants. Here, we have attempted to understand the haemocompatibility of chitosan by immobilizing a monolayer of cell mimetic lipid compositions. The phosphatidylcholine/cholesterol/galactocerebroside lipid composition (PC/Chol/GalC, 1:0.35:0.125) was deposited onto the chitosan films. Characterization of the modified surface was done by sessile drop contact angle measurement. The contact angle of the chitosan film reduced from 80.65 +/- 1.4 to 23.5 +/- 1.9 after the surface modification. Swelling nature of chitosan seemed to influence the orientation and packing of the lipid monolayer. In vitro calcification studies with metastable salt solution indicated increased calcification on the modified surface. This may be due to formation of nuclei for calcification on the expanding monolayer. The preliminary haemocompatibility studies with washed platelets, leukocytes and erythrocytes showed overall reduction in blood cell adhesion to the modified surfaces. Scanning electron microscopy was used for morphological characterization of platelet adhesion and activation on the surfaces. On the bare chitosan surface, fully spread platelets with extending pseudopodia indicated platelet activation. The smooth surface of the modified film did not activate platelets. These studies showed that, though the lipid monolayer on chitosan film is able to reduce the over all blood cell adhesion and platelet activation it is prone to calcification. PMID:16779768

Mathews, Smitha; Kaladhar, K; Sharma, Chandra P

2006-10-01

261

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

262

Synthesis and properties of Chitosan-silica hybrid aerogels  

SciTech Connect

Chitosan, a polymer that is soluble in dilute aqueous acid, is derived from chitin, a natural polyglucosamide. Aquagels where the solid phase consists of both chitosan and silica can be easily prepared by using an acidic solution of chitosan to catalyze the hydrolysis and condensation of tetraethylorthosilicate. Gels with chitosan/TEOS mass ratios of 0.1-1.1 have been prepared by this method. Standard drying processes using CO{sub 2} give the corresponding aerogels. The amount of chitosan in the gel plays a role in the shrinkage of the aerogel during drying. Gels with the lowest chitosan/silica ratios show the most linear shrinkage, up to 24%, while those with the highest ratios show only a 7% linear shrinkage. Pyrolysis at 700 C under nitrogen produces a darkened aerogel due to the thermal decomposition of the chitosan, however, the aerogel retains its monolithic form. The pyrolyzed aerogels absorb slightly more infrared radiation in the 2-5 {micro}m region than the original aerogels. B.E.T. surface areas of these aerogels range from 470-750 m{sup 2}/g. Biocompatibility screening of this material shows a very high value for hemolysis, but a low value for cytotoxicity.

Ayers, Michael R.; Hunt, Arlon J.

2001-06-01

263

Assembly of bioactive peptide-chitosan nanocomplexes.  

PubMed

The assembly of nanocomplexes from bioactive peptides, namely, caseinophosphopeptides (CPPs) and chitosan (CS), at physiological conditions and various CS/CPP mass ratios has been systematically studied using a combination of liquid chromatography-tandem mass spectrometry (LC-MS/MS), turbidimetric titration, dynamic light scattering (DLS), electrophoretic mobility (?-potential) measurements, transmission electron microscopy (TEM), and fluorescence spectroscopy. Peptides incorporated with CS forming nanoparticles were prepared and identified using LC-MS/MS. They were characterized by different amounts of clusters of phosphorylated seryl residues. At low salt concentrations, an increase in CS/CPP mass ratio shifted the critical pH(?1) value, which was designated as the formation of CS/CPP nanocomplexes, as well as pH(max), which represents the neutralization of positive and negative charges at higher pH values. The sizes, charges, morphologies, binding mechanisms, and binding constants of the bioactive peptide-chitosan nanocomplexes were analyzed, and our results suggest that three processes are involved in nanocomplex formation: First, negatively charged CPPs absorb to positively charged CS molecular chains to form intrapolymer nanocomplexes saturated with CPPs (CPPNPs). Subsequently, the negatively charged CPPNPs are bridged by the addition of positively charged CS, resulting in the formation of nearly neutral associative biopolymer complexes. Finally, further addition of excess chitosan breaks down the bridges of associative complexes and causes the formation of positively charged isolated spherical nanocomplexes. The binding between the peptides and CS is mainly driven by electrostatic interactions with a binding constant of K(cs) = 4.6 × 10(4) M(-1). Phosphorylated groups and other negatively charged amino acids, such as aspartic acid (Asp) and glutamic acid (Glu), in the CPPs might be the dominant sites for interaction with -NH(3)(+) groups on the CS molecular chains. PMID:21608974

Hu, B; Wang, S S; Li, J; Zeng, X X; Huang, Q R

2011-05-24

264

New generation of chitosan-encapsulated ZnO quantum dots loaded with drug: synthesis, characterization and in vitro drug delivery response.  

PubMed

The objective of the study is to describe a new approach of combining quantum dots technology with anti-cancer drug therapy. In this regard, we communicate the preliminary research on the synthesis of blue-light emitting ZnO quantum dots (QDs) combined with biodegradable chitosan (N-acetylglucosamine) for tumor-targeted drug delivery. The results presented here indicate that the proposed new generation of QDs loaded with anti-cancer agents and encapsulated with biocompatible polymer represent a potential platform to deliver tumor-targeted drugs and document the delivery process, if desired. Non-toxic water-dispersed ZnO QDs with long-term fluorescence stability were synthesized by a chemical hydrolysis method, encapsulated with chitosan and loaded with anti-cancer drug. Chitosan enhanced the stability of the QDs because of the hydrophilicity and cationic charge of chitosan. The study points toward the application of water-dispersed ZnO QDs with long-term fluorescence stability for design of new drug release carrier. PMID:20100604

Yuan, Q; Hein, S; Misra, R D K

2010-01-25

265

Separation of Cr(VI) on chitosan membranes  

SciTech Connect

Chitosan membranes were used for hexavalent chromium removal. Investigations covered membranes produced by phase inversion (wet-method). The modifications of membranes were made by acetylated and cross-linked Cu(II). In the experiments chitosan produced by the Sea Fisheries Institute, Poland, was used. The metal ions were removed on chitosan membranes during membrane processes. The modifications and the effect of the pH of the solution on the separation properties of membranes were determined. The concentration of metal ions was measured by the method of inductively coupled plasma (ICP) atomic emission spectrometry.

Modrzejewska, Z.; Kaminski, W.

1999-12-01

266

Novel chitin and chitosan nanofibers in biomedical applications.  

PubMed

Chitin and its deacetylated derivative, chitosan, are non-toxic, antibacterial, biodegradable and biocompatible biopolymers. Due to these properties, they are widely used for biomedical applications such as tissue engineering scaffolds, drug delivery, wound dressings, separation membranes and antibacterial coatings, stent coatings, and sensors. In the recent years, electrospinning has been found to be a novel technique to produce chitin and chitosan nanofibers. These nanofibers find novel applications in biomedical fields due to their high surface area and porosity. This article reviews the recent reports on the preparation, properties and biomedical applications of chitin and chitosan based nanofibers in detail. PMID:19913083

Jayakumar, R; Prabaharan, M; Nair, S V; Tamura, H

267

High yield production of monomer-free chitosan oligosaccharides by pepsin catalyzed hydrolysis of a high deacetylation degree chitosan.  

PubMed

The high molecular weight of chitosan, which results in a poor solubility at neutral pH values and high viscosity aqueous solutions, limits its potential uses in the fields of food, health and agriculture. However, most of these limitations are overcome by chitosan oligosaccharides obtained by enzymatic hydrolysis of the polymer. Several commercial enzymes with different original specificities were assayed for their ability to hydrolyze a 93% deacetylation degree chitosan and compared with a chitosanase. According to the patterns of viscosity decrease and reducing end formation, three enzymes--cellulase, pepsin and lipase A--were found to be particularly suitable for hydrolyzing chitosan at a level comparable to that achieved by chitosanase. Unlike the appreciable levels of both 2-amino-2-deoxy-D-glucose and 2-acetamido-2-deoxy-D-glucose monomers released from chitosan by the other enzymes after a 20h-hydrolysis (4.6-9.1% of the total product weight), no monomer could be detected following pepsin cleavage. As a result, pepsin produced a higher yield of chitosan oligosaccharides than the other enzymes: 52% versus as much as 46%, respectively. Low molecular weight chitosans accounted for the remaining 48% of hydrolysis products. The calculated average polymerization degree of the products released by pepsin was around 16 units after 20h of hydrolysis. This product pattern and yield are proposed to be related to the bond cleavage specificity of pepsin and the high deacetylation degree of chitosan used as substrate. The optimal reaction conditions for hydrolysis of chitosan by pepsin were 40 degrees C and pH 4.5, and an enzyme/substrate ratio of 1:100 (w/w) for reactions longer than 1h. PMID:17889843

Roncal, Tomás; Oviedo, Alberto; López de Armentia, Iratxe; Fernández, Laura; Villarán, M Carmen

2007-09-06

268

Chitosan encapsulated quantum dots platform for leukemia detection.  

PubMed

We report results of the studies relating to electrophoretic deposition of nanostructured composite of chitosan (CS)-cadmium-telluride quantum dots (CdTe-QDs) onto indium-tin-oxide coated glass substrate. The high resolution transmission electron microscopic studies of the nanocomposite reveal molecular level coating of the CdTe-QDs with CS molecules in the colloidal dispersion medium. This novel composite platform has been explored to fabricate an electrochemical DNA biosensor for detection of chronic myelogenous leukemia (CML) by immobilizing amine terminated oligonucleotide probe sequence containing 22 base pairs, identified from BCR-ABL fusion gene. The results of differential pulse voltammetry reveal that this nucleic acid sensor can detect as low as 2.56 pM concentration of complementary target DNA with a response time of 60s. Further, the response characteristics show that this fabricated bioelectrode has a shelf life of about 6 weeks and can be used for about 5-6 times. The results of experiments conducted using clinical patient samples reveal that this sensor can be used to distinguish CML positive and the negative control samples. PMID:22647531

Sharma, Aditya; Pandey, Chandra Mouli; Sumana, Gajjala; Soni, Udit; Sapra, Sameer; Srivastava, A K; Chatterjee, Tathagat; Malhotra, Bansi D

2012-05-16

269

Design of peptide-conjugated glycol chitosan nanoparticles for near infrared fluorescent (NIRF) in vivo imaging of bladder tumors  

NASA Astrophysics Data System (ADS)

Enhanced permeability and retention (EPR) effects for tumor treatment have been utilized as a representative strategy to accumulate untargeted nanoparticles in the blood vessels around tumors. However, the EPR effect itself was not sufficient for the nanoparticles to penetrate into cancer cells. For the improvement of diagnosis and treatment of cancer using nanoparticles, many more nanoparticles need to specifically enter cancer cells. Otherwise, can leave the tumor area and not contribute to treatment. In order to enhance the internalization process, specific ligands on nanoparticles can help their specific internalization in cancer cells by receptor-mediated endocytosis. We previously developed glycol chitosan based nanoparticles that suggested a promising possibility for in vivo tumor imaging using the EPR effect. The glycol chitosan nanoparticles showed a long circulation time beyond 1 day and they were accumulated predominantly in tumor. In this study, we evaluated two peptides for specific targeting and better internalization into urinary bladder cancer cells. We conjugated the peptides on to the glycol chitosan nanoparticles; the peptide-conjugated nanoparticles were also labeling with near infrared fluorescent (NIRF) dye, Cy5.5, to visualize them by optical imaging in vivo. Importantly real-time NIRF imaging can also be used for fluorescence (NIRF)-guided surgery of tumors beyond normal optical penetration depths. The peptide conjugated glycol chitosan nanoparticles were characterized with respect to size, stability and zeta-potential and compared with previous nanoparticles without ligands in terms of their internalization into bladder cancer cells. This study demonstrated the possibility of our nanoparticles for tumor imaging and emphasized the importance of specific targeting peptides.

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

2012-02-01

270

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.

2013-01-01

271

Glow discharge plasma in water: a green approach to enhancing ability of chitosan for dye removal.  

PubMed

There is a need to explore effective and green approaches to enhancing the ability to use chitosan for contaminant removal for practical implementation of this technology. In the present study, glow discharge plasma (GDP), which has thus far been studied for degradation of contaminants, was used for the first time to pre-treat chitosan for dye removal in aqueous solution. The results show that the GDP treatment changed the morphology and crystallinity of chitosan particles, and the number of -CH(2) and -CH(3) groups in the chitosan samples increased. Various pretreatment parameters, including discharge current and time, played significant roles in the chitosan modification. It is observed that dye uptake in GDP-modified chitosan was faster than adsorption in untreated chitosan. The maximum adsorption by chitosan followed the order of untreated chitosanchitosan (GDP current: 50 mA)chitosan (GDP current: 120 mA), implying that the chitosan modified by GDP had a higher maximum adsorption capacity in comparison with the untreated chitosan. A possible mechanism is proposed. These results show that GDP may be an attractive pretreatment technology for environmental adsorption materials. PMID:22169243

Wen, Yuezhong; Shen, Chensi; Ni, Yanyan; Tong, Shaoping; Yu, Feng

2011-11-25

272

Chitosan adhesive for laser tissue repair  

NASA Astrophysics Data System (ADS)

Background. Laser tissue repair usually relies on haemoderivate solders, based on serum albumin. These solders have intrinsic limitations that impair their widespread use, such as limited repair strength, high solubility, brittleness and viral transmission. Furthermore, the solder activation temperature (65-70 °C) can induce significant damage to tissue. In this study, a new laser-activated biomaterial for tissue repair was developed and tested in vitro and in vivo to overcome some of the shortcomings of traditional solders. Materials and Methods. Flexible and insoluble strips of chitosan adhesive (surface area ~34 mm2, thickness ~20 ?m) were developed and bonded on sheep intestine with a laser fluence and irradiance of 52 +/- 2 J/cm2 and ~15 W/cm2 respectively. The temperature between tissue and adhesive was measured using small thermocouples. The strength of repaired tissue was tested by a calibrated tensiometer. The adhesive was also bonded in vivo to the sciatic nerve of rats to assess the thermal damage induced by the laser (fluence = 65 +/- 11 J/cm2, irradiance = 15 W/cm2) four days post-operatively. Results. Chitosan adhesives successfully repaired intestine tissue, achieving a repair strength of 0.50 +/- 0.15 N (shear stress = 14.7 +/- 4.7 KPa, n=30) at a temperature of 60-65 °C. The laser caused demyelination of axons at the operated site; nevertheless, the myelinated axons retained their normal morphology proximally and distally.

Lauto, A.; Stoodley, M.; Avolio, A.; Foster, L. J. R.

2006-03-01

273

Chitosan macroporous foams obtained in highly concentrated emulsions as templates.  

PubMed

Emulsion templating is an effective route for the preparation of macroporous polymer foams, with well-defined pore structures. This kind of material is usually obtained by polymerization or crosslinking in the external phase of highly concentrated emulsions. The present article describes the synthesis of macroporous foams based on a cationic polymer, chitosan, crosslinked with genipin, a natural crosslinker. The phase behavior was used to study the influence of chitosan on surfactant self-aggregation. Hexagonal and lamellar liquid crystalline structures could be obtained in the presence of chitosan, and polymer did not greatly influence the geometric lattice parameters of these self-aggregates. O/W highly concentrated emulsions were obtained in the presence of chitosan in the continuous phase, which allowed reducing both droplet size and polydispersity. The emulsions were stable during the time required for crosslinking, obtaining macroporous foams with high pore volume and degree of crosslinking. PMID:24011788

Miras, Jonathan; Vílchez, Susana; Solans, Conxita; Esquena, Jordi

2013-08-12

274

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

2013-07-21

275

Properties of Novel Hydroxypropyl Methylcellulose Films Containing Chitosan Nanoparticles  

Technology Transfer Automated Retrieval System (TEKTRAN)

In this work, chitosan nanoparticles were prepared and incorporated in hydroxypropyl methylcellulose (HPMC) films under different conditions. Mechanical properties, water vapor and oxygen permeability, water solubility and scanning and transmission electron microscopy (SEM and TEM) results were ana...

276

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

2013-04-24

277

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.

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

2012-01-01

278

Reducing SO? in fresh pork burgers by adding chitosan.  

PubMed

The use of 0.02 or 0.05% chitosan is proposed to reduce from 450 to 150 mg kg?¹ the SO? required to preserve pork burgers aerobically packed and stored at 2 °C for up to 21 days under retail display conditions. The effects of chitosan and/or sulfite addition and the storage time were determined in fresh (color deterioration, lipid oxidation, pH, total viable counts, Escherichia coli and coliforms, Salmonella, appearance and odor) and cooked (appearance, odor, flavor and texture) burgers. The addition of either 0.02 or 0.05% chitosan was not detected by sensory analysis, and extended the shelf life of low-SO? burgers from 7 to 14 days. Chitosan enhanced the preservative effects of sulfite at a low dose, acting on the main causes of meat deterioration (bacterial spoilage, color stability and lipid oxidation), and provided good sensory properties to fresh and cooked pork burgers. PMID:22749538

Serrano, Rafael; Bañón, Sancho

2012-06-17

279

Nanocomposites based on modified chitosan and titanium oxide  

Microsoft Academic Search

The effect of primary amino groups and molecular mass of chitosan on the stability of suspensions based on nanoscale TiO2 dispersions in acidic solutions of various concentrations at pH 2.5 was studied. In the case of chitosan prepared according\\u000a to a commercialized process, the stability of TiO2 suspensions was low and depended on the concentration of the polymer solution. Solutions

A. N. Ozerin; A. N. Zelenetskii; T. A. Akopova; O. B. Pavlova-Verevkina; L. A. Ozerina; N. M. Surin; A. S. Kechek’yan

2006-01-01

280

Antioxidant activity of N-carboxymethyl chitosan oligosaccharides  

Microsoft Academic Search

Three N-carboxymethyl chitosan oligosaccharides (N-CMCOSs) with different degrees of substitution (NA: 0.28, NB: 0.41, and NC: 0.54, respectively) were prepared by the control of the amount of glyoxylic acid in the etherification process of chitosan oligosaccharide (COS). Their antioxidant activities were evaluated by the scavenging of 1,1-diphenyl-2-picrylhrazyl radical (DPPH) radical, superoxide anion and determination of reducing power. With the increasing

Tao Sun; Qian Yao; Dongxiang Zhou; Fang Mao

2008-01-01

281

Polylysine-functionalised thermoresponsive chitosan hydrogel for neural tissue engineering  

Microsoft Academic Search

Foetal mouse cortical cells were cultured on 2D films and within 3D thermally responsive chitosan\\/glycerophosphate salt (GP) hydrogels. The biocompatibility of chitosan\\/GP 2D films was assessed in terms of cell number and neurites per cell. Osmolarity of the hydrogel was a critical factor in promoting cell survival with isotonic GP concentrations providing optimal conditions. To improve cell adhesion and neurite

K. E. Cromptona; J. D. Goudc; R. V. Bellamkondac; D. I. Finkelsteine; M. K. Hornef; Howard Florey

282

Neuronal responses to simply prepared chitosan composite gels  

Microsoft Academic Search

Hydrogels have been favored as scaffolds for brain repair. However, most of the polymers used today for neural tissue scaffold fabrication require chemical functionalization with neuro-adhesive molecules, which raises potential challenges for their clinical applications. In the present study, simply prepared chitosan-based composite gels were developed by physically blending chitosan into agarose hydrogels as a neuro-adhesive component. The responses of

Zheng Cao; Wei He

2010-01-01

283

Polylysine-functionalised thermoresponsive chitosan hydrogel for neural tissue engineering  

Microsoft Academic Search

Foetal mouse cortical cells were cultured on 2D films and within 3D thermally responsive chitosan\\/glycerophosphate salt (GP) hydrogels. The biocompatibility of chitosan\\/GP 2D films was assessed in terms of cell number and neurites per cell. Osmolarity of the hydrogel was a critical factor in promoting cell survival with isotonic GP concentrations providing optimal conditions. To improve cell adhesion and neurite

K. E. Crompton; J. D. Goud; R. V. Bellamkonda; T. R. Gengenbach; D. I. Finkelstein; M. K. Horne; J. S. Forsythe

2007-01-01

284

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

285

Surface modification on silicon with chitosan and biological research  

Microsoft Academic Search

The aim of the present study was to investigate the effect of chitosan modification of silicon (Si) on protein adsorption, cell adhesion and cell proliferation. Chitosan was first immobilized on the Si surface through a (3-aminopropyl)triethoxysilane (APTES) bridge. The surface was then characterized by contact angle measurement, atomic force microscopy (AFM), x-ray photoelectron spectroscopy (XPS) and energy dispersive x-ray spectroscopy

Xiaoying Lü; Wei Cui; Yan Huang; Yi Zhao; Zhigong Wang

2009-01-01

286

Chitosan Nanoparticles: Preparation and Application in Antibacterial Paper  

Microsoft Academic Search

Chitosan nanoparticles (CSNP) were obtained by H2O2 degradation of chitosan. Their morphology and size were determined by atomic force microscope (AFM), and the particles were found smooth and approximately 36 nm in size. CSNP-0.5% HAc solutions (1, 2, 5, and 10 mg\\/mL) were used in antibacterial paper by addition in pulp, impregnation, dispersion coating on the handsheets, and insufflation. The

Ying Ma; Pengtao Liu; Chuanling Si; Zhong Liu

2010-01-01

287

Hydrophobically modified chitosan\\/gold nanoparticles for DNA delivery  

Microsoft Academic Search

Present study dealt an application of modified chitosan gold nanoparticles (Nac-6-Au) for the immobilization of necked plasmid\\u000a DNA. Gold nanoparticles stabilized with N-acylated chitosan were prepared by graft-onto approach. The stabilized gold nanoparticles were characterized by different\\u000a physico-chemical techniques such as UV-vis, TEM, ELS and DLS. MTT assay was used for in vitro cytotoxicity of the nanoparticles\\u000a into three different

Shanta Raj Bhattarai; Santosh Aryal; Narayan Bhattarai; Sun Young Kim; Ho Keun Yi; Pyoung Han Hwang; Hak Yong Kim

2008-01-01

288

Effect of Dietary Chitin and Chitosan on Cholesterolemia of Rats  

Microsoft Academic Search

imÛnek J., BartoÀová H.: Effect of dietary chitin and chitosan on cholesterolemia of rats. Acta Vet. Brno 2005, 74: 491-499. Chitin - chitosan is being advertised as a food supplement that effectively lowers blood cholesterol concentration and controls obesity. The lard-fed rat was chosen because this model shares similarities with human hypercholesterolemia. The male rats were divided into six groups

H. BARTO

289

Depolymerization of chitosan and substituted chitosans with the aid of a wheat germ lipase preparation  

Microsoft Academic Search

Chitosan was readily depolymerized by a wheat germ lipase preparation, from approximately 700,000 to 13,000 D, as shown by the viscosity decrease of its lactate solutions, gel permeation chromatography, electrophoresis, and titration of the reducing sugars. Typically, the viscosity was lowered to 35% of the initial value upon 10-min contact with lipase at 25°C. Measurements taken in the lipase concentration

Riccardo A. A. Muzzarelli; Wenshui Xia; Marco Tomasetti; Pierluca Ilari

1995-01-01

290

Ibuprofen-loaded chitosan and chemically modified chitosans--release features from tablet and film forms.  

PubMed

The biopolymer chitosan was chemically modified in two sequences of reactions: (i) immobilization of methyl acrylate followed by cysteamine and (ii) the sequence of immobilization reactions involving ethylene sulfide, methyl acrylate and finally cysteamine. In both cases the pendant chains have attached nitrogen, oxygen and sulfur basic centers. The corresponding structures were characterized through elemental analysis, infrared spectroscopy, nuclear magnetic resonance in the solid state for carbon, thermogravimetry and scanning electron microscopy. The newly synthesized biopolymers have abilities to immobilize and controllably release the non-steroidal drug ibuprofen. The ibuprofen-loaded biomaterials as tablets or as films crosslinked with glutaraldehyde revealed that drug release is pH sensitive. The chemically modified chitosan may allow reduction of drug release in stomach fluids, since the functional groups cause a decrease in swelling rate at pH 1.2, opposite to the behavior that occurs at pH 7.4, that of nutritional fluid, where an increase of the rate of swelling occurs. In such conditions the negatively charge ibuprofen is electrostatically repelled by negative chitosan derivative surfaces. PMID:23010457

Vieira, Adriana P; Badshah, Syed; Airoldi, Claudio

2012-09-23

291

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.

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

292

Chitosan-thioglycolic acid as a versatile antimicrobial agent.  

PubMed

As functionalized chitosans hold great potential for the development of effective and broad-spectrum antibiotics, representative chitosan derivatives were tested for antimicrobial activity in neutral media: trimethyl chitosan (TMC), carboxy-methyl chitosan (CMC), and chitosan-thioglycolic acid (TGA; medium molecular weight: MMW-TGA; low molecular weight: LMW-TGA). Colony forming assays indicated that LMW-TGA displayed superior antimicrobial activity over the other derivatives tested: a 30 min incubation killed 100% Streptococcus sobrinus (Gram-positive bacteria) and reduced colony counts by 99.99% in Neisseria subflava (Gram-negative bacteria) and 99.97% in Candida albicans (fungi). To elucidate LMW-TGA effects at the cellular level, microscopic studies were performed. Use of fluorescein isothiocyanate (FITC)-labeled chitosan derivates in confocal microscopy showed that LMW-TGA attaches to microbial cell walls, while transmission electron microscopy indicated that this derivative severely affects cell wall integrity and intracellular ultrastructure in all species tested. We therefore propose LMW-TGA as a promising and effective broad-band antimicrobial compound. PMID:23470196

Geisberger, Georg; Gyenge, Emina Besic; Hinger, Doris; Käch, Andres; Maake, Caroline; Patzke, Greta R

2013-03-07

293

The use of chitosan to damage Cryptococcus neoformans biofilms.  

PubMed

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

2009-10-09

294

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.

Venkatesan, Jayachandran; Kim, Se-Kwon

2010-01-01

295

Preparation and evaluation of inhalable itraconazole chitosan based polymeric micelles  

PubMed Central

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

2012-01-01

296

Electrophoretic deposition of composite hydroxyapatite-silica-chitosan coatings  

SciTech Connect

Electrophoretic deposition (EPD) method has been developed for the fabrication of nanocomposite silica-chitosan coatings. Cathodic deposits were obtained on various conductive substrates using suspensions of silica nanoparticles in a mixed ethanol-water solvent, containing dissolved chitosan. Co-deposition of silica and hydroxyapatite (HA) nanoparticles resulted in the fabrication of HA-silica-chitosan coatings. The deposition yield has been studied at a constant voltage mode at various deposition durations. The method enabled the formation of coatings of different thickness in the range of up to 100 {mu}m. Deposit composition, microstructure and porosity can be varied by variation of HA and silica concentration in the suspensions. It was demonstrated that EPD can be used for the fabrication of HA-silica-chitosan coatings of graded composition and laminates. The method enabled the deposition of coatings containing layers of silica-chitosan and HA-chitosan nanocomposites using suspensions with different HA and silica content. Obtained coatings were studied by X-ray diffraction, thermogravimetric and differential thermal analysis, scanning electron microscopy and energy dispersive spectroscopy. The mechanism of deposition is discussed.

Grandfield, K. [Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4L7 (Canada); Zhitomirsky, I. [Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4L7 (Canada)], E-mail: zhitom@mcmaster.ca

2008-01-15

297

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

298

Synthesis and antifungal activity of thiadiazole-functionalized chitosan derivatives.  

PubMed

A groups of novel water soluble chitosan derivatives containing 1,3,4-thiadiazole group were synthesized including 1,3,4-thiadiazole (TPCTS), 2-methyl-1,3,4-thiadiazole (MTPCTS), and 2-phenyl-1,3,4-thiadiazole (PTPCTS). Their antifungal activity against three kinds of phytopathogens was estimated by hypha measurement in vitro, and the fungicidal assessment shows that the synthesized chitosan derivatives have excellent activity against tested fungi. Of all the synthesized chitosan derivatives, MTPCTS inhibited the growth of the tested phytopathogens most effectively with inhibitory indices of 75.3%, 82.5%, and 65.8% against Colletotrichum lagenarium (Pass) Ell.et halst, Phomopsis asparagi (Sacc.) Bubak, and Monilinia fructicola (Wint.) Honey respectively at 1.0 mg/mL. These indices are higher than those of chitosan. These data also demonstrate that the hydrophobic moiety (alkyl and phenyl) and the length of alkyl substituent in thiadiazole tend to affect the antifungal activity of chitosan derivatives. It is hypothesized that thiadiazole groups enable the synthesized chitosan to possess obviously better antifungal activity and good solubility in water. PMID:23624516

Li, Qing; Ren, Jianming; Dong, Fang; Feng, Yan; Gu, Guodong; Guo, Zhanyong

2013-03-21

299

Stability of chitosan nanoparticles cross-linked with tripolyphosphate.  

PubMed

The physical stability of chitosan nanoparticles cross-linked with sodium tripolyphosphate (TPP) was investigated over a period of 1 month. Special emphasis was placed on changes in the particle size and the particle compactness, which are two important physicochemical parameters of nanoparticulate drug delivery systems. The chitosan-TPP particles were prepared at different ionic strengths, chitosan chloride concentrations, and TPP-to-chitosan ratios. In the presence of monovalent salt, the positive ? potential of the particles was reduced. In spite of this, the particles were more stable when prepared and stored under saline conditions compared to water. This could be attributed to the smaller particle sizes found in the presence of sodium chloride. Most of the particles prepared in saline solvents were stable with respect to changes in the size and the compactness of the particles. However, instability was observed at the highest cross-linker-to-polymer ratios. Generally, a reduction in the ? potential and an increase in the particle compactness were observed at increasing TPP-to-chitosan ratios. This combined with the size increase induced by a high concentration of chitosan, increased the aggregation and sedimentation tendency of the particles and reduced the colloidal stability of the particles. PMID:23046433

Jonassen, Helene; Kjøniksen, Anna-Lena; Hiorth, Marianne

2012-10-09

300

Influence of iron oxide nanoparticles on the rheological properties of hybrid chitosan ferrogels.  

PubMed

Magnetite nanoparticles have been successfully synthesized in the presence of chitosan using an in situ coprecipitation method in alkali media. This method allows obtaining chitosan ferrogels due to the simultaneous gelation of chitosan. The chitosan concentration has been varied and its effects on the particle synthesis investigated. It has been demonstrated that high chitosan concentrations prevents the formation of magnetite due to the slow diffusion of the alkali species through the viscous medium provided by chitosan, instead iron hydroxides are formed. The presence of magnetite nanoparticles increases the elastic modulus which results in a reinforcement of the chitosan ferrogels. This effect is counterbalanced by the disruption of hydrogen bonding responsible for the formation of chitosan hydrogels in alkali media. PMID:19699487

Hernández, Rebeca; Zamora-Mora, Vanessa; Sibaja-Ballestero, María; Vega-Baudrit, José; López, Daniel; Mijangos, Carmen

2009-08-06

301

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

302

Chitosan blended bacterial cellulose as a smart material for biomedical application  

NASA Astrophysics Data System (ADS)

Bacterial cellulose and chitosan blends have been successfully prepared by immersing wet bacterial cellulose pellicle in chitosan solution followed by freeze-drying. By changing chitosan concentration and immersion time, the chitosan content in the blends is ranged from 12% to 45%. The products look like a foam structure. SEM images show that chitosan molecules can penetrate into bacterial cellulose forming multilayer structure. The foam has very well interconnected porous network structure and large aspect surface. By incorporation of chitosan in bacterial cellulose, XRD patterns indicate that crystalline structure does not change but crystallinity decreases from 82% to 61% with chitosan content increasing from 12% to 45%. According to TGA results, the thermal stability has been improved. At the same time, the mechanical properties of bacterial cellulose and chitosan blends are good enough for potential biomedical application such as tissue engineering scaffold and would dressing material.

Cai, Zhijiang; Jin, Hyoung-Joon; Kim, Jaehwan

2009-03-01

303

Mechanical property, degradation rate, and bone cell growth of chitosan coated titanium influenced by degree of deacetylation of chitosan.  

PubMed

Chitosan has shown promise as a coating for dental/craniofacial and orthopaedic implants. However, the effects of degree of deacetylation (DDA) of chitosan on coating bond strength, degradation, and biological performance is not known. The aim of this project was to evaluate bonding, degradation, and bone cell growth on titanium coated with chitosans of different DDA and from different manufacturers. Three different chitosans, 80.6%, 81.7%, and 92.3% DDA were covalently bonded to titanium coupons via silane-glutaraldehyde molecules. Bond strengths were evaluated in mechanical tensile tests, and degradation, over 5 weeks, was conducted in cell culture medium with and without 100 microg/mL lysozyme. Cytocompatibility was evaluated for 10 days using UMR 106 osteoblastic cells. Results showed that mean chitosan coating bond strengths ranged from 2.2-3.8 MPa, and that there was minimal affect of DDA on coating bond strengths. The coatings exhibited little dissolution over 5 weeks in medium with or without lysozyme. However, the molecular weight (MW) of the chitosan coatings remaining on the titanium samples after 5 weeks decreased by 69-85% with the higher DDA chitosan coatings exhibiting less percent change in MW than the lower DDA materials. The growth of the UMR 106 osteoblast cells on the 81.7% DDA chitosan coating was lower on days 3 and 5, as compared with the other two coatings, but by day 10, there were no differences in growth among three coatings or to the uncoated titanium controls. Differences in growth were attributed to differences in manufacturer source material, though all coatings were judged to be osteocompatible in vitro. PMID:18161778

Yuan, Youling; Chesnutt, Betsy M; Wright, Lee; Haggard, Warren O; Bumgardner, Joel D

2008-07-01

304

Live encapsulated Lactobacillus acidophilus cells in yogurt for therapeutic oral delivery: preparation and in vitro analysis of alginate-chitosan microcapsules.  

PubMed

Targeted delivery of live microencapsulated bacterial cells has strong potential for application in treating various diseases, including diarrhea, kidney failure, liver failure, and high cholesterol, among others. This study investigates the potential of microcapsules composed of two natural polymers, alginate and chitosan (AC), and the use of these artificial cells in yogurt for delivery of probiotic Lactobacillus acidophilus bacterial live cells. Results show that the integrity of AC microcapsules was preserved after 76 h of mechanical shaking in MRS broth and after 12 h and 24 h in simulated gastric and intestinal fluids. Using an in vitro computer-controlled simulated human gastrointestinal (GI) model, we found 8.37 log CFU/mL of viable bacterial cells were present after 120 min of gastric exposure and 7.96 log CFU/mL after 360 min of intestinal exposure. In addition, AC microcapsules composed of chitosan 10 and 100 at various concentrations were subjected to 4-week storage in 2% milk fat yogurt or 0.85% physiological solution. It was found that 9.37 log CFU/mL of cells encapsulated with chitosan 10 and 8.24 log CFU/mL of cells encapsulated with chitosan 100 were alive after 4 weeks. The AC capsule composed of 0.5% chitosan 10 provided the highest bacterial survival of 9.11 log CFU/mL after 4 weeks. Finally, an investigation of bacterial viability over 72 h in different pH buffers yielded highest survival of 6.34 log CFU/mL and 10.34 log CFU/mL at pH 8 for free and AC-encapsulated cells, respectively. We conclude from these findings that encapsulation allows delivery of a higher number of bacteria to desired targets in the GI tract and that microcapsules containing bacterial cells are good candidates for oral artificial cells for bacterial cell therapy. PMID:18066134

Urbanska, Aleksandra Malgorzata; Bhathena, Jasmine; Prakash, Satya

2007-09-01

305

In vitro biocompatibility of chitosan porous skin regenerating templates (PSRTs) using primary human skin keratinocytes  

Microsoft Academic Search

Biopolymer chitosan (?-1,4-d-glucosamine) comprises the copolymer mixture of N-acetylglucosamine and glucosamine. The natural biocompatibility and biodegradability of chitosan have recently highlighted its potential use for applications in wound management. Chemical and physical modifications of chitosan influence its biocompatibility and biodegradability, but it is unknown as to what degree. Hence, the biocompatibility of the chitosan porous skin regenerating templates (PSRT 82,

C. K. Lim; N. S. Yaacob; Z. Ismail; A. S. Halim

2010-01-01

306

Synthesis of chitosan-amino acid conjugates and their use in heavy metal uptake  

Microsoft Academic Search

Chitosan-amino acid conjugates were prepared by coupling amino acid esters to the carboxyl group of glyoxylic acid-substituted chitosan. The removal of heavy metals (Cu, Ni, Co and Mn) was increased by introduction of amino acids to chitosan, especially for Mn. Heavy metals were almost completely removed by chitosan-amino acid conjugates from solutions at an initial concentration of 100 parts per

Hiroshi Ishii; Maiko Minegishi; Boonma Lavitpichayawong; Tomoyo Mitani

1995-01-01

307

The Shape Memory Properties of Biodegradable Chitosan\\/Poly( l -lactide) Composites  

Microsoft Academic Search

The shape memory behavior of PLLA (poly(l-lactide)) and chitosan\\/PLLA composites was studied. PLLA and chitosan were compounded to fabricate novel materials which\\u000a may have biodegradability and biocompatibility. Chitosan does not significantly affect the glass and melting transition temperature\\u000a of the PLLA. Both the pure PLLA and chitosan\\/PLLA composites showed shape memory effect arising from the viscoelastic properties\\u000a of PLLA comprised

Qinghao MengJinlian; Jinlian Hu; KaiChiu Ho; Fenglong Ji; Shaojun Chen

2009-01-01

308

Hyaluronic acid interaction with chitosan-conjugated magnetite particles and its purification  

Microsoft Academic Search

The polyelectrolyte complex (PEC) effect between hyaluronic acid (HA) and chitosan was explored to recover HA from fermentation broth. Chitosan was conjugated with the magnetic nanoparticles by co-precipitation method to facilitate its recovery. The magnetic chitosan particles (chitosan–magnetite) have an average size about 5?m and point of zero charge (PZC) around 6.5. pH lower than PZC favored the HA capture.

Pei-Fen Yang; Cheng-Kang Lee

2007-01-01

309

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

310

Antimicrobial Actions of Degraded and Native Chitosan against Spoilage Organisms in Laboratory Media and Foods  

Microsoft Academic Search

The objective of this study was to determine whether chitosan (poly-b-1,4-glucosamine) and hydrolysates of chitosan can be used as novel preservatives in foods. Chitosan was hydrolyzed by using oxidative-reductive degradation, crude papaya latex, and lysozyme. Mild hydrolysis of chitosan resulted in improved microbial inactivation in saline and greater inhibition of growth of several spoilage yeasts in laboratory media, but highly

J. Rhoades; S. Roller

2000-01-01

311

Pervaporation dehydration of isopropanol-water mixtures using chitosan zeolite-a membranes  

Microsoft Academic Search

Pervaporation (PV) dehydration of isopropanol (IPA) using modified chitosan membranes was studied. The membranes were prepared from chitosan and were modified by using zeolite-A. Pre-weighed amount of zeolite-A was added into acidic solvent and stirred to produce homogeneous solution. Chitosan flakes were then added into the solution and stirred overnight. Various ratios of zeolite-A and chitosan from 1:20 to 1:2

Ngoc Tram

312

Selective separation of germanium(IV) by 2,3-dihydroxypropyl chitosan resin  

Microsoft Academic Search

2,3-Dihydroxypropyl chitosan resin, prepared from chitosan and a 1,2-diol, adsorbed only germanium(IV) from aqueous solutions containing semimetals over the range of acidic to weakly basic media. The adsorption capacities of the chitosan resin were up to about 1.4mmolg?1. The selective separation of germanium(IV) from tellurium(VI) and boron was achieved with a column method using the chitosan resin. The breakthrough points

Yoshinari Inukai; Toyotaka Chinen; Toshio Matsuda; Yasuhiko Kaida; Seiji Yasuda

1998-01-01

313

The synthesis of chitosan-based silver nanoparticles and their antibacterial activity  

Microsoft Academic Search

Chitosan-based silver nanoparticles were synthesized by reducing silver nitrate salts with nontoxic and biodegradable chitosan. The silver nanoparticles thus obtained showed highly potent antibacterial activity toward both Gram-positive and Gram-negative bacteria, comparable with the highly active precursor silver salts. Silver-impregnated chitosan films were formed from the starting materials composed of silver nitrate and chitosan via thermal treatment. Compared with pure

Dongwei Wei; Wuyong Sun; Weiping Qian; Yongzhong Ye; Xiaoyuan Ma

2009-01-01

314

Effect of gamma radiation on dilute aqueous solutions and thin films of N-succinyl chitosan  

Microsoft Academic Search

N-Succinyl chitosan (N-SC) products with various degrees of substitution were synthesized by a direct reaction between chitosan and succinic anhydride. The susceptibility of the as-synthesized polymers to degradation upon their exposure to ?-ray radiation was investigated. The results were compared with the as-received chitosan. The size exclusion chromatographic results showed that chitosan and N-SC products in their dilute aqueous solution

Chutima Vanichvattanadecha; Pitt Supaphol; Naotsugu Nagasawa; Masao Tamada; Seiichi Tokura; Tetuya Furuike; Hiroshi Tamura; Ratana Rujiravanit

2010-01-01

315

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

316

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

Microsoft Academic Search

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 2mg 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

Maneerat Khemkhao; Boonyarit Nuntakumjorn; Somkiet Techkarnjanaruk; Chantaraporn Phalakornkule

2011-01-01

317

Preparation and optimization of chitosan nanoparticles and magnetic chitosan nanoparticles as delivery systems using Box-Behnken statistical design.  

PubMed

Chitosan nanoparticles and magnetic chitosan nanoparticles can be applied as delivery systems for the anti-Alzheimer drug tacrine. Investigation was carried out to elucidate the influence of process parameters on the mean particle size of chitosan nanoparticles produced by spontaneous emulsification. The method was optimized using design of experiments (DOE) by employing a 3-factor, 3-level Box-Behnken statistical design. This statistical design is used in order to achieve the minimum size and suitable morphology of nanoparticles. Also, magnetic chitosan nanoparticles were synthesized according to optimal method. The designed nanoparticles have average particle size from 33.64 to 74.87nm, which were determined by field emission scanning electron microscopy (FE-SEM). Drug loading in the nanoparticles as drug delivery systems has been done according to the presented optimal method and appropriate capacity of drug loading was shown by ultraviolet spectrophotometry. Chitosan and magnetic chitosan nanoparticles as drug delivery systems were characterized by Diffuse Reflectance Fourier Transform Mid Infrared spectroscopy (DR-FTMIR). PMID:23571126

Elmizadeh, Hamideh; Khanmohammadi, Mohammadreza; Ghasemi, Keyvan; Hassanzadeh, Gholamreza; Nassiri-Asl, Marjan; Garmarudi, Amir Bagheri

2013-03-18

318

Chitosan solution enhances the immunoadjuvant properties of GM-CSF  

PubMed Central

Sustained, local delivery of immunomodulatory cytokines is under investigation for its ability to enhance vaccine and anti-tumor responses both clinically and preclinically. This study evaluates the ability of chitosan, a biocompatible polysaccharide, to (1) control the dissemination of a cytokine, GM-CSF, and (2) enhance the immunoadjuvant properties of GM-CSF. While cytokines have previously been delivered in lipid-based adjuvants and other vehicles, these do not have the clinical safety profile or unique properties of chitosan. We found that chitosan solution maintained a measurable depot of recombinant GM-CSF (rGM-CSF) at a subcutaneous injection site for up to 9 days. In contrast, when delivered in a saline vehicle, rGM-CSF was undetectable in 12 to 24 hours. Furthermore, a single s.c. injection of 20?g rGM-CSF in chitosan solution (chitosan/rGM-CSF(20?g)) transiently expanded lymph nodes up to 4.6-fold and increased the number of MHC class II expressing cells and dendritic cells by 7.4-fold and 6.8-fold, respectively. These increases were significantly greater than those measured when rGM-CSF was administered in saline at the standard preclinical dose and schedule, i.e. 4 daily s.c. injections of 20?g. Furthermore, lymph node cells from mice injected with chitosan/rGM-CSF(20?g) induced greater allogeneic T cell proliferation, indicating enhanced antigen presenting capability, than lymph node cells from mice injected with rGM-CSF alone. Finally, in vaccination experiments, chitosan/rGM-CSF was superior to either chitosan or rGM-CSF alone in enhancing the induction of antigen-specific CD4+ proliferation, peptide-specific CD8+ pentamer staining and cytotoxic T cell lysis. Altogether, chitosan/rGM-CSF outperformed standard rGM-CSF administrations in dendritic cell recruitment, antigen presentation and vaccine enhancement. We conclude that chitosan solution is a promising delivery platform for the sustained, local delivery of rGM-CSF.

Zaharoff, David A.; Rogers, Connie J.; Hance, Kenneth W.; Schlom, Jeffrey; Greiner, John W.

2008-01-01

319

In vitro evaluation of the viscoelastic properties of chitosan–thioglycolic acid conjugates  

Microsoft Academic Search

The aim of this study was to evaluate the viscoelastic properties of chitosan–thioglycolic acid conjugates with different amounts of thiol groups immobilized on the polymer. The modification of chitosan was achieved via the covalent attachment of thioglycolic acid mediated by a carbodiimide. Chitosan–thioglycolic acid conjugates displaying 120, 209 and 439 ?M thiol groups per gram of polymer were synthesized. The

Margit D Hornof; Constantia E Kast; Andreas Bernkop-Schnürch

2003-01-01

320

Studies on the Interfacial Interaction in Natural Rubber Latex\\/Chitosan Blends  

Microsoft Academic Search

Chitosan (CS) has been blended with natural rubber (NR) latex by solution casting method followed by compression molding at 140°C. The blend is found to be incompatible from DSC, morphology and FTIR studies. The water absorbability of blends increases with increasing percentage of chitosan in the blend. Blending has improved the thermal properties of chitosan. The blended samples show enhanced

Jobish Johns; Vijayalakshmi Rao

2012-01-01

321

Evaluation of a modified chitosan biopolymer for coagulation of colloidal particles  

Microsoft Academic Search

Chitosan, a deacetylated derivative of chitin, is a biodegradable cationic polymer. 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. Chitosan can be modified with various pretreatments including dissolution

Jill Ruhsing Pan; Chihpin Huang; Shuchuan Chen; Ying-Chien Chung

1999-01-01

322

Preparation and characterization of chitosan-heparin composite matrices for blood contacting tissue engineering  

Microsoft Academic Search

Chitosan has been widely used for biomaterial scaffolds in tissue engineering because of its good mechanical properties and cytocompatibility. However, the poor blood compatibility of chitosan has greatly limited its biomedical utilization, especially for blood contacting tissue engineering. In this study, we exploited a polymer blending procedure to heparinize the chitosan material under simple and mild conditions to improve its

Qing He; Qiang Ao; Kai Gong; Lihai Zhang; Min Hu; Yandao Gong; Xiufang Zhang

2010-01-01

323

Preparation and NMR characterization of highly substituted N-trimethyl chitosan chloride  

Microsoft Academic Search

N,N,N-Trimethyl chitosan chloride (TMC) is a chemically modified chitosan with improved aqueous solubility, compared with the native chitosan. It is essential to follow a synthesis procedure in which the degree of substitution of the final product can be controlled by means of the number of reaction steps, the duration of each reaction step and the amount of methyl iodide as

A. B. Sieval; M. Thanou; A. F. Kotze´; J. C. Verhoef; J. Brussee; H. E. Junginger

1998-01-01

324

The antifungal properties of chitosan in laboratory media and apple juice  

Microsoft Academic Search

The antimicrobial properties of chitosan glutamate, a derivative of chitin, were investigated in laboratory media and apple juice against 15 yeasts and moulds associated with food spoilage in order to assess the potential for using chitosan as a natural food preservative. Of the seven strains of filamentous fungi studied, chitosan reduced the growth rate of Mucor racemosus at 1 g\\/l

S. Roller; N. Covill

1999-01-01

325

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

326

Influence of the degree of acetylation on some biological properties of chitosan films  

Microsoft Academic Search

In this study, we investigated in vitro the role of the degree of acetylation (DA) on some biological properties of chitosan films. We noticed that, whatever the DA, all chitosan films were cytocompatible towards keratinocytes and fibroblasts. We also demonstrated that the higher the DA of chitosan, the lower was the cell adhesion on the films. Fibroblasts appear to adhere

Claire Chatelet; Odile Damour; Alain Domard

2001-01-01

327

Chitosan induced resistance to downy mildew in sunflower caused by Plasmopara halstedii  

Microsoft Academic Search

Induction of resistance to downy mildew caused by Plasmopara halstedii in sunflower was studied after treatment with chitosan. Treatment of sunflower seeds with 5% chitosan resulted in decreased disease severity and offered 46 and 52% protection under greenhouse and field conditions respectively. The induction of resistance to P. halstedii by chitosan was accompanied by the accumulation of various host defense-related

P. Nandeeshkumar; J. Sudisha; Kini K. Ramachandra; H. S. Prakash; S. R. Niranjana; Shetty H. Shekar

2008-01-01

328

Characteristics and kinetic study of chitosan prepared from seafood industry waste for oil spills cleanup  

Microsoft Academic Search

Chitosan being a biodegradable material would be an eco-friendly and effective alternative in the cleaning up of oil spills. In the present study, adsorbent (Chitosan) was prepared from the seafood industry waste, prawn shells for removal of oil from aqueous solution. Batch experiments were carried out to study the kinetics for the removal of oil from oil–water solutions using chitosan.

Amita Ummadisingu; Suresh Gupta

2012-01-01

329

Comparison of Lactic Acid Bacteria Fermentation with Acid Treatments for Chitosan Production from Shrimp Waste  

Microsoft Academic Search

The traditional procedure for chitosan production involves use of a strong acid (HCl) for demineralization of chitin. This study reports application of a mixed culture of lactic acid bacteria (Lactobacillus plantarum, Lactobacillus acidophilus, and Lactobacillus lactis) fermentation in demineralization of chitin for chitosan production from shrimp waste. Chitosan produced from shrimp waste with lactic acid bacteria fermentation at 30°C for

Sureerat Phuvasate; Yi-Cheng Su

2010-01-01

330

Antibacterial hydroxyapatite\\/chitosan complex coatings with superior osteoblastic cell response  

Microsoft Academic Search

Chitosan was widely used as an antibacterial component. While most antibacterial materials also possess cytotoxicities, we hypothesize that selectively destruction of bacterial cells can be achieved by controlling the material parameters of chitosan, due to its intrinsic antibacterial mechanism. In this study, porous hydroxyapatite coatings prepared by the liquid precursor plasma spraying process were used for loading the chitosan with

Lei Song; Lu Gan; Yan-Feng Xiao; Yao Wu; Fang Wu; Zhong-Wei Gu

2011-01-01

331

REMOVAL OF BORON FROM INDUSTRIAL WASTEWATER BY CHITOSAN VIA CHEMICAL PRECIPITATION  

Microsoft Academic Search

Chitosan is natural organic polyelectrolytes of high molecular weight and charge density; obtained from deacetylation of chitin. This study explored the potential and effectiveness of applying chitosan as a primary coagulant and flocculent for boron removal. A series of batch coagulation and flocculation processes with chitosan under different conditions, i.e. dosage, pH and temperature were conducted, in order to determine

MOHD ARIFFIN; ABU HASSAN; LIM SOO HUI; ZAINURA ZAINON NOOR

332

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

333

Selective antimicrobial action of chitosan against spoilage yeasts in mixed culture fermentations  

Microsoft Academic Search

The effect of chitosan on Saccharomyces cerevisiae (the yeast that carries out alcohol fermentation), Brettanomyces bruxellensis and Brettanomyces intermedius (contaminants of alcohol fermentations), was investigated. The effect of chitosan was tested on each yeast, as well as on mixed cultivations of S. cerevisiae + B. bruxellensis and S. cerevisiae + B. intermedius. Chitosan enhanced the lag period of both strains

Leticia Gómez-Rivas; Blanca I. Escudero-Abarca; M. Guadalupe Aguilar-Uscanga; Patricia M. Hayward-Jones; Patricia Mendoza; Mario Ramírez

2004-01-01

334

Oral delivery of insulin using chitosan capsules cross-linked with phytic acid.  

PubMed

Phytic acid (PA) was used as a cross-linking agent for encapsulation of insulin in a chitosan matrix for oral delivery of insulin. PA-chitosan capsules were compared with tripolyphosphate (TPP)-chitosan capsules for stable oral delivery of insulin. During 2 h incubation in simulated gastric fluid, PA-chitosan capsules prepared using pH 6, 6% PA solutions showed better stability than TPP-chitosan capsules prepared using pH 7, 6% TTP solution. PA-chitosan capsules released less than 60% of their encapsulated insulin after 24 h incubation in simulated gastrointestinal fluids. TPP-chitosan capsules showed burst release and virtually the entire insulin content was released in 12 h. Both capsule types were tested in vivo via oral drug administration using diabetic mice. PA-chitosan capsules significantly decreased blood glucose levels while TPP-chitosan capsules caused a lesser reduction. The relative pharmacological bioactivity of PA-chitosan capsules prepared was 6.4% while that of TPP-chitosan capsules was 1.1%. PA-chitosan capsules appeared to have good potential for use in oral delivery of insulin for sustained control of the blood glucose level. PMID:21537061

Lee, Hyunah; Jeong, Chanmin; Ghafoor, Kashif; Cho, Sungyeon; Park, Jiyong

2011-01-01

335

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.

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

2013-01-01

336

Genetic Improvement of Bacillus licheniformis Strains for Efficient Deproteinization of Shrimp Shells and Production of High-Molecular-Mass Chitin and Chitosan ? †  

PubMed Central

By targeted deletion of the polyglutamate operon (pga) in Bacillus licheniformis F11, a derivative form, F11.1 (?pga), was obtained that, along with lacking polyglutamate (PGA) formation, displayed enhanced proteolytic activities. The phenotypic properties were maintained in a strain in which the chiBA operon was additionally deleted: F11.4 (?chiBA ?pga). These genetically modified strains, carrying the ?pga deletion either alone (F11.1) or together with the ?chiBA (F11.4) deletion, were used in fermentations (20-liter scale) aiming at the deproteinization of shrimp shells in order to obtain long-chain chitin. After chemical deacetylation, the resulting chitosan samples were analyzed by nuclear magnetic resonance spectroscopy, size exclusion chromatography, and viscometry and compared to a chitosan preparation that was produced in parallel by chemical methods by a commercial chitosan supplier (GSRmbH). Though faint lipid impurities were present in the fermented polysaccharides, the viscosity of the material produced with the double-deletion mutant F11.4 (?pga ?chiBA) was higher than that of the chemically produced and commercially available samples (Cognis GmbH). Thus, enhanced proteolytic activities and a lack of chitinase activity render the double mutant F11.4 a powerful tool for the production of long-chain chitosan.

Hoffmann, Kerstin; Daum, Gabriele; Koster, Marina; Kulicke, Werner-Michael; Meyer-Rammes, Heike; Bisping, Bernward; Meinhardt, Friedhelm

2010-01-01

337

Inactivation of Salmonella on whole cantaloupe by application of an antimicrobial coating containing chitosan and allyl isothiocyanate  

Technology Transfer Automated Retrieval System (TEKTRAN)

This study investigated the antimicrobial effect of a chitosan coating + allyl isothiocyanate (AIT) and nisin against Salmonella on whole fresh cantaloupes. Cantaloupes were inoculated with a cocktail of three Salmonella strains and treated with chitosan, chitosan + AIT, chitosan + nisin, and chitos...

338

Morphology Controlled Growth of Chitosan-Bound Microtubes and a Study of their Biocompatibility and Antibacterial Activity  

Microsoft Academic Search

Self-assembled peptide microtubes are fabricated with the biopolymer chitosan. The micro- tubes are covalently attached to chitosan and the morphology of the chitosan assembled on the surface of the microtubes can be tuned by altering the pH of the growth solution. Cytotoxicity studies in the presence of mouse embryonic fibroblasts indicate that the chitosan- bound microtubes are highly biocompatible and

Marsiyana M. Henricus; Karl R. Fath; Monica Z. Menzenski; Ipsita A. Banerjee

2009-01-01

339

Physicochemical Properties of Edible and Preservative Films from Chitosan\\/Cassava Starch\\/Gelatin Blend Plasticized with Glycerol  

Microsoft Academic Search

Summary Edible films from chitosan, cassava starch, and gelatin plasticized with glycerol have been developed by casting method, and the effects of cassava starch (50, 100 and 150 g per 100 g of chitosan), gelatin (0, 25 and 50 g per 100 g of chitosan) and glycerol (21, 42 and 63 g per 100 g of chitosan) from the film

Qiu-Ping Zhong; Wen-Shui Xia

340

The Effect of the Degree of Deacetylation of Chitosan Nanoparticles and its Characterization and Encapsulation Efficiency on Drug Delivery  

Microsoft Academic Search

In this study, we investigated the effects of the degree of deacetylation (DD) of chitosan on the resulting nanoparticles' properties. The diameters of the nanoparticles increased as the DD of chitosan decreased. In addition, we prepared fluorouracil-loaded chitosan nanoparticles and characterized them using FTIR and NMR spectroscopy. The encapsulation efficiency increased with the DD of chitosan. Particles produced using 90%-DD

Hui-Chia Yang; Min-Hsiung Hon

2010-01-01

341

Intranasal Delivery of Chitosan Nanoparticles for Migraine Therapy  

PubMed Central

Objective The objective of the research was to formulate and evaluate sumatriptan succinate-loaded chitosan nanoparticles for migraine therapy in order to improve its therapeutic effect and reduce dosing frequency. Material and Methods The Taguchi method design of experiments (L9 orthogonal array) was applied to obtain the optimized formulation. The sumatriptan succinate-loaded chitosan nanoparticles (CNPs) were prepared by ionic gelation of chitosan with tripolyphosphate anions (TPP) and Tween 80 as surfactant. Results The CNPs had a mean size of 306.8 ± 3.9 nm, a zeta potential of +28.79 mV, and entrapment efficiency of 75.4 ± 1.1%. The in vitro drug release of chitosan nanoparticles was evaluated in phosphate buffer saline pH 5.5 using goat nasal mucosa and found to be 76.7 ± 1.3% within 28 hours. Discussion The release of the drug from the nanoparticles was anomalous, showing non-Fickian diffusion indicating that drug release is controlled by more than one process i.e. the superposition of both phenomena, a diffusion-controlled as well as a swelling-controlled release. This is clearly due to the characteristics of chitosan which easily dissolves at low pH, thus a nasal pH range of 5.5 ± 0.5 supports it very well. The mechanism of pH-sensitive swelling involves protonation of the amine groups of chitosan at low pH. This protonation leads to chain repulsion, diffusion of protons and counter ions together with water inside the gel, and the dissociation of secondary interactions. Conclusion The results suggest that sumatriptan succinate-loaded chitosan nanoparticles are the most suitable mode of drug delivery for promising therapeutic action.

Gulati, Neha; Nagaich, Upendra; Saraf, Shubhini A.

2013-01-01

342

Recent advancement of chitosan-based nanoparticles for oral controlled delivery of insulin and other therapeutic agents.  

PubMed

Nanoparticles composed of naturally occurring biodegradable polymers have emerged as potential carriers of various therapeutic agents for controlled drug delivery through the oral route. Chitosan, a cationic polysaccharide, is one of such biodegradable polymers, which has been extensively exploited for the preparation of nanoparticles for oral controlled delivery of several therapeutic agents. In recent years, the area of focus has shifted from chitosan to chitosan derivatized polymers for the preparation of oral nanoparticles due to its vastly improved properties, such as better drug retention capability, improved permeation, enhanced mucoadhesion and sustained release of therapeutic agents. Chitosan derivatized polymers are primarily the quaternized chitosan derivatives, chitosan cyclodextrin complexes, thiolated chitosan, pegylated chitosan and chitosan combined with other peptides. The current review focuses on the recent advancements in the field of oral controlled release via chitosan nanoparticles and discusses about its in vitro and in vivo implications. PMID:21153572

Chaudhury, Anumita; Das, Surajit

2010-12-11

343

Amperometric immunobiosensor for ?-fetoprotein using Au nanoparticles/chitosan/TiO(2)-graphene composite based platform.  

PubMed

A simple label-free amperometric immunosensor for protein detection is developed based on TiO(2)-graphene (TiO(2)-Gr), chitosan and gold nanoparticles (AuNPs) composite film modified glassy carbon electrode (GCE). The negatively charged AuNPs can be adsorbed on the positively charged chitosan/TiO(2)-Gr composite film by electrostatic adsorption, and then is used to immobilize ?-fetoprotein antibody for the assay of ?-fetoprotein (AFP). The interaction of antigen and antibody on the electrode interface makes a barrier for electrons and inhibits the electro-transfer, resulting in the decreased DPV signals of probe Fe(CN)(6)(3-/4-). Using this strategy, a wide detection range (0.1-300 ng mL(-1)) with the correlation coefficients of 0.992-0.994 for model target AFP is obtained. The limit of detection is 0.03 ng mL(-1) at a signal-to-noise ratio of 3. The results prove that the sensing strategy possesses sensitivity, selectivity, stability and generality, and it may be used to immobilize other biomoleculars to develop biosensor for the detection of other antigens or biocompounds. PMID:23165290

Huang, Ke-Jing; Li, Jing; Wu, Ying-Ying; Liu, Yan-Ming

2012-11-07

344

Genipin-cross-linked fucose-chitosan/heparin nanoparticles for the eradication of Helicobacter pylori.  

PubMed

Helicobacter pylori is a significant human pathogen that recognizes specific carbohydrate receptors, such as the fucose receptor, and produces the vacuolating cytotoxin, which induces inflammatory responses and modulates the cell-cell junction integrity of the gastric epithelium. The clinical applicability of topical antimicrobial agents was needed to complete the eradication of H. pylori in the infected fundal area. In the present study, we combined fucose-conjugated chitosan and genipin-cross-linking technologies in preparing multifunctional genipin-cross-linked fucose-chitosan/heparin nanoparticles to encapsulate amoxicillin of targeting and directly make contact with the region of microorganism on the gastric epithelium. The results show that the nanoparticles effectively reduced drug release at gastric acids and then released amoxicillin in an H. pylori survival situation to inhibit H. pylori growth and reduce disruption of the cell-cell junction protein in areas of H. pylori infection. Furthermore, with amoxicillin-loaded nanoparticles, a more complete H. pylori clearance effect was observed, and H. pylori-associated gastric inflammation in an infected animal model was effectively reduced. PMID:23499480

Lin, Yu-Hsin; Tsai, Shih-Chang; Lai, Chih-Ho; Lee, Che-Hsin; He, Zih Sian; Tseng, Guan-Chin

2013-03-15

345

Ionically cross-linked chitosan microspheres for controlled release of bioactive nerve growth factor.  

PubMed

Controlled release of neurotrophic factors to target tissue via microsphere-based delivery systems is critical for the treatment strategies of diverse neurodegenerative disorders. The present study aims to investigate the feasibility of the controlled release of bioactive nerve growth factor (NGF) with ionically cross-linked chitosan microspheres (NGF-CMSs). The microspheres were prepared by the emulsion-ionic cross-linking method with sodium tripolyphosphate (STPP) as an ionic cross-linking agent. The size and distribution of the microspheres, SEM images, Fourier transform infra red spectroscopy (FT-IR), encapsulation efficiency, in vitro release tests and bioactivity assay were subsequently evaluated. We found that the microspheres had relatively rough surfaces with mean sizes between 20 and 31?m. FT-IR results provided evidence of ionic interaction between amino groups and phosphoric groups of chitosan and STPP. The NGF encapsulation efficiency ranged from 63% to 88% depending on the concentration of STPP. The in vitro release profiles of NGF from NGF-CMSs were influenced by the concentration of STPP. NGF-CMSs which were cross-linked with higher concentration of STPP showed slower but sustained release of NGF. In addition, the released NGF from NGF-CMSs was capable of maintaining the viability of PC12 cells, as well as promoting their differentiation. Taken together, our findings suggest that NGF-CMSs are capable of releasing bioactive NGF over 7 days, thus having potential application in nerve injury repair. PMID:22001532

Zeng, Wen; Huang, Jinghui; Hu, Xueyu; Xiao, Wei; Rong, Mengyao; Yuan, Zhi; Luo, Zhuojing

2011-10-06

346

ThermoSensitive Release Behavior of 5Fluorouracil from Chitosan-Gel Microspheres Coated with Lipid Multilayers  

Microsoft Academic Search

In order to provide a device that would release anticancer drugs in response to temperature, chitosan microspheres with immobilized 1-[N-(5- aminopentyl)urea]-5-fluorouracil (Ap-5FU) and coated with dipalmitoyl phosphatidyl choline (DPPC) multilayers were prepared. The chitosan-DPPC- chitosan microspheres were prepared by coating chitosan-DPPC microspheres with polyelectrolyte complex membrane of chitosan. Good distributive stability of microspheres in aqueous solution was achieved with the

Y. Ohya; T. Takei; T. Ouchi

1992-01-01

347

Quality and Shelf Life of Mango (Mangifera Indica L. cv. `Tainong') Coated by Using Chitosan and Polyphenols  

Microsoft Academic Search

Chitosan-based coatings were used to delay ripening and prolong shelf-life of mango fruit stored at 15±1°C and 85—90% RH for 35 days. Mango fruits were treated with 2% chitosan solution or with 2% chitosan containing 1% tea polyphenols (TP—chitosan). Samples were taken at regular intervals for analysis. Results indicated that chitosan coating alone could decrease the decay incidence and weight

J. Wang; B. Wang; W. Jiang; Y. Zhao

2007-01-01

348

Preparation of cross-linked carboxymethyl chitosan for repairing sciatic nerve injury in rats  

Microsoft Academic Search

A successful nerve regeneration process was achieved with nerve repair tubes made up of 1-ethyl-3(3-dimethylaminopropyl) carbodiimide\\u000a hydrochloride (EDC) cross-linked carboxymethyl chitosan (CM-chitosan) with improved biodegradability. Chitosan has a very\\u000a slow degradation rate, while the EDC cross-linked CM-chitosan tubes degraded to 30% of original weight during 8 weeks of incubation\\u000a in lysozyme solution. In vitro cell culture indicated that the CM-chitosan films

Gan Wang; Guangyuan Lu; Qiang Ao; Yandao Gong; Xiufang Zhang

2010-01-01

349

Adsorption of heavy metal ions, dyes and proteins by chitosan composites and derivatives — A review  

NASA Astrophysics Data System (ADS)

Chitosan composites and derivatives have gained wide attentions as effective biosorbents due to their low costs and high contents of amino and hydroxyl functional groups. They have showed significant potentials of removing metal ions, dyes and proteins from various media. Chemical modifications that lead to the formation of the chitosan derivatives and chitosan composites have been extensively studied and widely reported in literatures. The aims of this review were to summarize the important information of the bioactivities of chitosan, highlight the various preparation methods of chitosan-based active biosorbents, and outline its potential applications in the adsorption of heavy metal ions, dyes and proteins from wastewater and aqueous solutions.

Liu, Bingjie; Wang, Dongfeng; Yu, Guangli; Meng, Xianghong

2013-09-01

350

Green synthesis and stabilization of gold nanoparticles in chemically modified chitosan matrices  

Microsoft Academic Search

Chitosan-N-2-methylhydroxypyridine-6-methylcorboxylate (Ch-PDC) and chitosan-N-2-methylhydroxypyridine-6-methylhydroxy thiocarbohydrazide (Ch-PDC-Th) were synthesized for the first time using chitosan as precursor. Chitosan, Ch-PDC, Ch-PDC-Th were used in the synthesis of gold nanoparticles (AuNP) in aqueous medium. Chitosan and Ch-PDC-Th possess reducing properties which enabled the ‘green’ synthesis of AuNPs. The stabilization of the AuNPs was as a result of the thiocarbide (SC) and amine (NH2)

Anand D. Tiwari; Ajay K. Mishra; Shivani B. Mishra; Omotayo A. Arotiba; Bhekie B. Mamba

2011-01-01

351

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

352

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

2012-11-14

353

Electrophoretic deposition of composite hydroxyapatite-chitosan coatings  

SciTech Connect

Cathodic electrophoretic deposition has been utilized for the fabrication of composite hydroxyapatite-chitosan coatings on 316L stainless steel substrates. The addition of chitosan to the hydroxyapatite suspensions promoted the electrophoretic deposition of the hydroxyapatite nanoparticles and resulted in the formation of composite coatings. The obtained coatings were investigated by X-ray diffraction, thermogravimetric and differential thermal analysis, scanning and transmission electron microscopy, potentiodynamic polarization measurements, and electrochemical impedance spectroscopy. It was shown that the deposit composition can be changed by a variation of the chitosan or hydroxyapatite concentration in the solutions. Experimental conditions were developed for the fabrication of hydroxyapatite-chitosan nanocomposites containing 40.9-89.8 wt.% hydroxyapatite. The method enabled the formation of adherent and uniform coatings of thicknesses up to 60 {mu}m. X-ray studies revealed that the preferred orientation of the hydroxyapatite nanoparticles in the chitosan matrix increases with decreasing hydroxyapatite content in the composite coatings. The obtained coatings provided the corrosion protection for the 316L stainless steel substrates00.

Pang Xin [Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4L7 (Canada); Zhitomirsky, Igor [Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4L7 (Canada)]. E-mail: zhitom@mcmaster.ca

2007-04-15

354

Low molecular weight chitosan conjugated with folate for siRNA delivery in vitro: optimization studies  

PubMed Central

The low transfection efficiency of chitosan is one of its drawbacks as a gene delivery carrier. Low molecular weight chitosan may help to form small-sized polymer-DNA or small interfering RNA (siRNA) complexes. Folate conjugation may improve gene transfection efficiency because of the promoted uptake of folate receptor-bearing cells. In the present study, chitosan was conjugated with folate and investigated for its efficacy as a delivery vector for siRNA in vitro. We demonstrate that the molecular weight of chitosan has a major influence on its biological and physicochemical properties, and very low molecular weight chitosan (below 10 kDa) has difficulty in forming stable complexes with siRNA. In this study, chitosan 25 kDa and 50 kDa completely absorbed siRNA and formed nanoparticles (?220 nm) at a chitosan to siRNA weight ratio of 50:1. The introduction of a folate ligand onto chitosan decreased nanoparticle toxicity. Compared with chitosan-siRNA, folate-chitosan-siRNA nanoparticles improved gene silencing transfection efficiency. Therefore, folate-chitosan shows potential as a viable candidate vector for safe and efficient siRNA delivery.

Fernandes, Julio C; Qiu, Xingping; Winnik, Francoise M; Benderdour, Mohamed; Zhang, Xiaoling; Dai, Kerong; Shi, Qin

2012-01-01

355

Development and In Vitro Characterization of Galactosylated Low Molecular Weight Chitosan Nanoparticles Bearing Doxorubicin  

PubMed Central

The aim of the present research was to evaluate the potential of galactosylated low molecular weight chitosan (Gal-LMWC) nanoparticles bearing positively charged anticancer, doxorubicin (DOX) for hepatocyte targeting. The chitosan from crab shell was depolymerized, and the lactobionic acid was coupled with LMWC using carbodiimide chemistry. The depolymerized and galactosylated polymers were characterized. Two types of Gal-LMWC(s) with variable degree of substitution were employed to prepare the nanoparticles using ionotropic gelation with pentasodium tripolyphosphate anions. Factors affecting nanoparticles formation were discussed. The nanoparticles were characterized by transmission electron microscopy and photon correlation spectroscopy and found to be spherical in the size range 106–320 nm. Relatively higher percent DOX entrapment was obtained for Gal-LMWC(s) nanoparticles than for LMWC nanoparticles. A further increase in drug entrapment was found with nanoparticles prepared by Gal-LMWC with higher degree of substitution. A hypothesis which correlates the ionic concentration of DOX in nanoparticles preparation medium and percent DOX entrapment in cationic polymer has been proposed to explain the enhanced DOX entrapment. In-vitro drug release study demonstrated an initial burst release followed by a sustained release. The targeting potential of the prepared nanoparticles was assessed by in vitro cytotoxicity study using the human hepatocellular carcinoma cell line (HepG2) expressing the ASGP receptors on their surfaces. The enthusiastic results showed the feasibility of Gal-LMWC(s) to entrap the cationic DOX and targeting potential of developed Gal-LMWC(s) nanoparticles to HepG2 cell line.

Jain, Nitin K.

2010-01-01

356

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

2008-06-20

357

Study of the effects of chitosan upon Streptococcus mutans adherence and biofilm formation.  

PubMed

The main aim of this work was to access the potential use of high and low molecular weight chitosans as potential oral antimicrobials, particularly as antibiofilm agents. Chitosan's interference with Streptococcus mutans capability to adhere and form biofilms was assessed. Additionally the effect upon mature and polymicrobial biofilms was also evaluated. The results obtained showed that chitosan was capable of interfering with S. mutans adhesion and primary biofilm formation. This action was observed up to a week with little to none decrease in efficiency. In addition chitosan was capable of inhibiting biofilms formed by two microorganisms and was capable of acting upon mature biofilms leading to significant reductions (94%) in biofilm survival. However clear statistical differences (p < 0.05) were registered in all assays with, in most assays, HMw chitosan presenting higher efficiency than LMw chitosan. Considering this results chitosan's potential as a valid alternative to traditional antimicrobials in oral health it's evident. PMID:23454497

Costa, E M; Silva, S; Tavaria, F K; Pintado, M M

2013-02-27

358

Metal accumulation in Lolium perenne and Brassica napus as affected by application of chitosans.  

PubMed

The effects of chitosan, a fishery waste-based material, and its derivative glutaraldehyde cross-linked chitosan (chitosan-GLA) on metal uptake by Lolium perenne (perennial ryegrass) and Brassica napus (rapeseed) were studied in a greenhouse pot experiment. Metal uptake by perennial ryegrass was highly dependent on the rate of addition of the chitosans. Low application rate (1% w/w) enhanced metal uptake, whereas 10% (w/w) addition decreased metal uptake. It was estimated that chitosan 1% (w/w) treatment could assist perennial ryegrass to remove approximately 3.2 kg Zn/ha and 0.29 kg Pb/ha. For rapeseed, metal uptake was decreased at all rates of application of chitosans. The ammonium acetate extractable metals in soil decreased following application of chitosans and plant growth. PMID:22908653

Kamari, A; Pulford, I D; Hargreaves, J S J

2012-10-01

359

Production of chitosan from endolichenic fungi isolated from mangrove environment and its antagonistic activity  

PubMed Central

Objective To screen the chitosan producing ability of endolichenic fungi and its antibacterial activity. Methods Lichen collected from mangroves was screened for endophytes and the chitosan producing ability of endolichenic fungi by submerged fermentation was also determined. Antibacterial activity was carried out against different pathogens. Results Totally 4 different groups of fungi were isolated from the lichen Roccella montagnei. Among the four genera, Aspergillus niger (A. niger) is potential to produce chitosan (1.3 g/L) on the twelfth day of incubation. Glucose plays an important role in the productivity of chitosan and the yield was maximum at 10% (1.93 g/L). Antibacterial activity revealed that Vibrio cholerae was sensitive to chitosan followed by Escherichia coli. Conclusions In conclusion, our findings suggest that A. niger is a potential candidate to produce more chitosan than the other strains and glucose plays an important role in the production of chitosan which proves to have a good antibacterial activity.

Logesh, AR; Thillaimaharani, KA; Sharmila, K; Kalaiselvam, M; Raffi, SM

2012-01-01

360

Influence of molecular character of chitosan on the adsorption of chitosan to oil droplet interfaces in an in vitro digestion model  

Microsoft Academic Search

The relationship between the adsorption of chitosan to oil droplet interfaces (surface adsorption) and the molecular characteristics of the chitosan (molecular weight and charge density) was examined using an in vitro digestion model. This model involved adding different concentrations (3–10 wt%) of oil droplets to a 0.1 wt% chitosan solution at pH 3 to simulate consumption of an oil-containing meal after ingestion

T. Helgason; J. Gislason; D. J. McClements; K. Kristbergsson; J. Weiss

2009-01-01

361

Development and in vitro evaluation of thiolated chitosan--Poly(methacrylic acid) nanoparticles as a local mucoadhesive delivery system.  

PubMed

The main objective of this study was to develop a local, oral mucoadhesive metronidazole benzoate (MET) delivery system that can be applied and removed by the patient for the treatment of periodontal diseases. The results of present study revealed that the retention time of MET at its absorption site could be increased by formulating it into nanoparticles using thiolated chitosan (TCS)-poly(methacrylic acid) (PMAA). The nanoparticles of MET prepared from TCS-PMAA may represent a useful approach for targeting its release at its site of absorption, sustaining its release and improving its oral availability. PMID:21215774

Saboktakin, Mohammad Reza; Tabatabaie, Roya M; Maharramov, Abel; Ramazanov, Mohammad Ali

2011-01-06

362

Synthesis and characterization of pH-dependent glycol chitosan and dextran sulfate nanoparticles for effective brain cancer treatment.  

PubMed

A novel drug delivery system for the treatment of brain tumors was formulated by methotrexate (MTX)-loaded polymeric nanoparticles (NPs) based on Glycol chitosan (GCS) and Dextran sulfate (DS). The physicochemical properties of resulting particles were investigated, evidencing the contribution of these nanoparticles for brain targeting. In vitro release of MTX was also evaluated. The GCS-DS nanoparticles have been developed based on the modulation of ratio show promise as a system for controlled delivery of the drug to the brain. PMID:21782844

Saboktakin, Mohammad Reza; Tabatabaie, Roya M; Maharramov, Abel; Ramazanov, Mohammad Ali

2011-07-19

363

Adhesion and viability of two enterococcal strains on covalently grafted chitosan and chitosan/kappa-carrageenan multilayers.  

PubMed

Chitosans are natural aminopolysaccharides, whose low cytotoxicity suggests their potential use for nonadhesive, antibacterial coatings on biomaterials implant surfaces. Here, the antiadhesive behavior and ability to kill bacteria upon adhesion ("contact killing") of chitosan coatings were evaluated for two strains of Enterococcus faecalis, isolated from clogged biliary stents. Chitosan coatings covalently grafted or applied as chitosan/kappa-carrageenan multilayers were characterized by ellipsometry, scanning force microscopy (SFM), X-ray photoelectron spectroscopy (XPS), and electrokinetic measurements. Decreases in initial bacterial deposition rates and the number of bacteria adhering in a more advanced state of the adhesion process were observed on both types of modified surfaces, with more pronounced effects on highly hydrated multilayers. Adhesion of negatively charged enterococci was slightly enhanced on chitosan-terminated multilayers, but antibacterial effect was absent on kappa-carrageenan-terminated multilayers. Thus, the efficacy of multilayers remains an interesting interplay between the promoting effect of cationically charged groups on adhesion of negatively charged bacteria and, on the other hand, their antibacterial effects. PMID:17705532

Bratskaya, S; Marinin, D; Simon, F; Synytska, A; Zschoche, S; Busscher, H J; Jager, D; van der Mei, H C

2007-08-18

364

Study of polyelectrolyte complexes of chitosan and sulfoethyl cellulose  

NASA Astrophysics Data System (ADS)

The complexing of polycation chitosan and polyanion sulphoethyl cellulose during the formation of polyelectrolyte simplex membranes using the layer-by-layer deposition of a solution of one polyion on a gel-like film of another one has been studied. The structural characteristics of the multilayer composites and their components have been analyzed by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray microanalysis. A technique is proposed for studying the structure of surface layers of thin polymer films (15-20 ?m) using a portable DIFREI-401 diffractometer. It is shown that the sequence of layer deposition during the formation of membrane films does not affect their structural characteristics. The interaction between positively charged chitosan groups (-NH{3/+}) and negatively charged sulfoethyl cellulose groups (-SO{3/-}) during the growth of polyelectrolyte complexes results in a packing of chitosan chains in the multilayer film.

Baklagina, Yu. G.; Kononova, S. V.; Petrova, V. A.; Kruchinina, E. V.; Nud'ga, L. A.; Romanov, D. P.; Klechkovskaya, V. V.; Orekhov, A. S.; Bogomazov, A. V.; Arkhipov, S. N.

2013-03-01

365

Development of multifunctional chitosan beads for fluoride removal.  

PubMed

Chitosan beads (CB) which have negligible defluoridation capacity (DC) have been chemically modified by introducing multifunctional groups, viz., NH(3)(+) and COOH groups by means of protonation and carboxylation in order to utilize both amine and hydroxyl groups for fluoride removal. The protonated cum carboxylated chitosan beads (PCCB) showed a maximum DC of 1800 mg F(-)/kg whereas raw chitosan beads displayed only 52 mg F(-)/kg. Sorption process was found to be independent of pH and slightly influenced in the presence of other common anions. The fluoride sorption on modified forms was reasonably explained by Freundlich and Langmuir isotherms. The sorbents were characterised by FTIR and SEM with EDAX analysis. The sorption process follows pseudo-second-order and intraparticle diffusion kinetic models. The suitability of PCCB has been tested with field sample collected from a nearby fluoride endemic area. PMID:19200651

Viswanathan, Natrayasamy; Sairam Sundaram, C; Meenakshi, S

2009-01-10

366

Superhydrophobic chitosan-based coatings for textile processing  

NASA Astrophysics Data System (ADS)

A simple method to design the superhydrophobic anti-bacterial textile for biomedical applications was developed. For the coating formulation the spraying of nanoparticles dispersion over the textile sample was applied, allowing the way to get multiscale textured layer on a top of cotton fabric. The anti-bacterial functionality of coating is supported by using chitosan-based nanoparticles. In our approach the fabrication of nanoparticles was based on electrostatic interaction between amine group of chitosan and negatively charged fluoroanion. It was demonstrated that the relative number of fluoroanions per elementary unit of chitosan plays the crucial role in the structure of aggregates in the coating and its wettability as well as in durability of coatings in contact with aqueous media.

Ivanova, N. A.; Philipchenko, A. B.

2012-12-01

367

A new route for chitosan immobilization onto polyethylene surface.  

PubMed

Low-density polyethylene (LDPE) belongs to commodity polymer materials applied in biomedical applications due to its favorable mechanical and chemical properties. The main disadvantage of LDPE in biomedical applications is low resistance to bacterial infections. An antibacterial modification of LDPE appears to be a solution to this problem. In this paper, the chitosan and chitosan/pectin multilayer was immobilized via polyacrylic acid (PAA) brushes grafted on the LDPE surface. The grafting was initiated by a low-temperature plasma treatment of the LDPE surface. Surface and adhesive properties of the samples prepared were investigated by surface analysis techniques. An antibacterial effect was confirmed by inhibition zone measurements of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The chitosan treatment of LDPE led to the highest and most clear inhibition zones (35 mm(2) for E. coli and 275 mm(2) for S. aureus). PMID:22944408

Popelka, Anton; Novák, Igor; Lehocký, Marián; Junkar, Ita; Mozeti?, Miran; Kleinová, Angela; Janigová, Ivica; Slouf, Miroslav; Bílek, František; Chodák, Ivan

2012-07-16

368

Preparation of Magnetic Chitosan Nanoparticles for Diverse Biomedical Applications  

NASA Astrophysics Data System (ADS)

Polymeric nanoparticles with magnetic properties can be potentially used in many fields such as biotechnology, separation processes, optoelectronic, catalysts and/or sensors, medical diagnosis and therapy. In this respect, biopolymers give promising trends due to their excellent biocompatibility and biodegradability. Therefore in this study, magnetic chitosan/Fe3O4 nanoparticles were prepared according to the procedure based on the ionic gelation of chitosan with tripolyphosphate anions. The formation of the particles was a result of the interaction between the negatively charged groups of the tripolyphosphate and the positively charged amino groups of chitosan. The prepared samples were observed by atomic force microscopy to obtain information about the morphology. The mean particle size of the nanoparticles was determined by dynamic light scattering measurements. Nanoparticles were spherical in shape with a particle size range of about 250-400 nm according to obtained data. Magnetic properties of the nanoparticles were determined by using ESR and VSM.

Kavaz, D.; Çirak, T.; Öztürk, E.; Bayram, C.; Denkba?, E. B.

369

Characterization of biomimetic calcium phosphate on phosphorylated chitosan films.  

PubMed

This study examined the effect of chitosan degree of deacetylation (DDA), concentration of simulated body fluid (SBF), and mineralization time on the composition, structure, and crystallinity of calcium phosphate (CaP) biomimetically deposited on chitosan and on osteoblast cell growth. Phosphorylated chitosan films of 92.3%, 87.4%, and 80.6% DDA were soaked in SBF (1.0x or 1.5x) for 7, 14, or 21 days. Scanning electron microscopy revealed that CaP precipitated from 1.5x SBF had a porous, granular morphology; while the coatings precipitated in 1.0x SBF were smoother and more uniform. X-ray diffraction showed that films mineralized in 1.0x SBF were amorphous, while films mineralized in 1.5x SBF for 21 days exhibited crystalline peaks similar to hydroxyapatite, with the most crystalline peaks seen on 92.3% DDA chitosan. When mineralized films were placed in cell media for 14 days, more calcium phosphate precipitated onto all films, and the most calcium phosphate was found on 92.3% DDA films mineralized in 1.5x SBF. After seven days of osteoblast culture, there were approximately three times as many cells (based on DNA measurements, p < 0.05) on 92.3% DDA films soaked in 1.0x SBF for seven or 21 days than on 80.6% DDA films soaked in 1.0x SBF for any length of time or any films soaked in 1.5x SBF. The DDA of chitosan, concentration of SBF and mineralization time affect the structure of and biological response to chitosan/biomimetic CaP films, and these factors must be considered when designing new materials to be used in orthopaedic and dental/craniofacial implant applications. PMID:17295230

Chesnutt, B M; Yuan, Y; Brahmandam, N; Yang, Y; Ong, J L; Haggard, W O; Bumgardner, J D

2007-08-01

370

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

371

Electrochemical DNA biosensor for the detection of Trichoderma harzianum based on a gold electrode modified with a composite membrane made from an ionic liquid, ZnO nanoparticles and chitosan, and by using acridine orange as a redox indicator  

Microsoft Academic Search

An electrochemical DNA biosensor was developed that is based on a gold electrode modified with a nanocomposite membrane made\\u000a from an ionic liquid, ZnO nanoparticles and chitosan. A single-stranded DNA probe was immobilized on this electrode. Acridine\\u000a orange was used as the hybridization probe for monitoring the hybridization of the target DNA. The biosensor was capable of\\u000a detecting target DNA

Shafiquzzaman Siddiquee; Nor Azah Yusof; Abu Bakar Salleh; Soon Guan Tan; Fatimah Abu Bakar

2011-01-01

372

Chitosan: Its Applications in Drug-Eluting Devices  

Microsoft Academic Search

\\u000a \\u000a Abstract  Chitosan, a naturally occurring polysaccharide derived from chitin, has been widely applied in drug delivery, tissue regeneration,\\u000a wound healing, blood coagulation, and immunostimulation due to its well-known biocompatibility and biodegradability. Additionally,\\u000a because of its unique cationic nature and the gel\\/film\\/matrix-forming capabilities, chitosan has been considered as a promising\\u000a material for the development of medical devices. The current concept for developing

Mei-Chin Chen; Fwu-Long Mi; Zi-Xian Liao; Hsing-Wen Sung

373

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

374

[Preparation of superparamagnetic paclitaxel nanoparticles from modified chitosan and their cytotoxicity against malignant brain glioma].  

PubMed

We synthesized the superparamagnetic paclitaxel nanoparticles from modified chitosan tangling around Fe3O4 ferrofluid and taxol, and observed the nanoparticles with transmission electronic microscopy (TEM). Then we evaluated the paramagnetism of the particles by vibration specimen magnetometer (VSM) and tested their cytotoxicity with flow cytometry (FCM). The prepared nanoparticle solution was black without any floccule or sediment and appeared transparent after diluted. The nanoparticles were spherical and dispersed in water with mean diameter of 15 nm under TEM and showed superparamagnetic character. FCM test showed the nanoparticles had significant toxic effects against malignant astrocytoma U251 cell lines, equal to taxol alone. These results showed that the superparamagnetic nanoparticle not only enhanced the solubility of paclitaxel in water, but also was superparamagnetic and cytotoxic, which make suitable tools for magnetic targeting chemotherapy of brain gliomas. PMID:21774213

Zhao, Ming; Li, Anmin; Chang, Jin; Wang, Hanjie; Liang, Shuli; Zhang, Jiajing; Yan, Runmin

2011-06-01

375

Synthesis and characterization of chitosan hydrogels containing 5-aminosalicylic acid nanopendents for colon: specific drug delivery.  

PubMed

The main aim of this research was to develop and evaluate a multiparticulate system of Ac-poly(amidoamine)(PAMAM)(G4)-chitosan (CS) hydrogels exploiting pH-sensitive and specific biodegradability properties for colon-targeted delivery of 5-aminosalicylic acid (5-ASA). All formulations were evaluated for particle size, encapsulation efficiency, swellability, and in vitro drug release. The size of the hydrogel was found to nanorange. The integrity of 5-ASA in the release fraction was assessed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The CS-Ac-PAMAM hydrogel was developed based on the modulation of ratio show promise as a system for controlled delivery of drug. PMID:20821391

Saboktakin, Mohammad Reza; Tabatabaie, Roya M; Maharramov, Abel; Ramazanov, Mohammad Ali

2010-12-01

376

One-step biofunctionalization of quantum dots with chitosan and N-palmitoyl chitosan for potential biomedical applications.  

PubMed

Carbohydrates and derivatives (such as glycolipids, glycoproteins) are of critical importance for cell structure, metabolism and functions. The effects of carbohydrate and lipid metabolic imbalances most often cause health disorders and diseases. In this study, new carbohydrate-based nanobioconjugates were designed and synthesized at room temperature using a single-step aqueous route combining chitosan and acyl-modified chitosan with fluorescent inorganic nanoparticles. N-palmitoyl chitosan (C-Pal) was prepared aiming at altering the lipophilic behavior of chitosan (CHI), but also retaining its reasonable water solubility for potential biomedical applications. CHI and C-Pal were used for producing biofunctionalized CdS quantum dots (QDs) as colloidal water dispersions. Fourier transform infrared spectroscopy (FTIR), thermal analysis (TG/DSC), surface contact angle (SCA), and degree of swelling (DS) in phosphate buffer were used to characterize the carbohydrates. Additionally, UV-Visible spectroscopy (UV-Vis), photoluminescence spectroscopy (PL), dynamic light scattering (DLS), scanning and transmission electron microscopy (SEM/TEM) were used to evaluate the precursors and nanobioconjugates produced. The FTIR spectra associated with the thermal analysis results have undoubtedly indicated the presence of N-palmitoyl groups "grafted" to the chitosan chain (C-Pal) which significantly altered its behavior towards water swelling and surface contact angle as compared to the unmodified chitosan. Furthermore, the results have evidenced that both CHI and C-Pal performed as capping ligands on nucleating and stabilizing colloidal CdS QDs with estimated average size below 3.5 nm and fluorescent activity in the visible range of the spectra. Therefore, an innovative "one-step" process was developed via room temperature aqueous colloidal chemistry for producing biofunctionalized quantum dots using water soluble carbohydrates tailored with amphiphilic behavior offering potential applications as fluorescent biomarkers in the investigation of glycoconjugates for the nutrition, biology, pharmaceutical, and medicine fields. PMID:23736790

Santos, Joyce C C; Mansur, Alexandra A P; Mansur, Herman S

2013-06-04

377

Chitosan-based luminescent/magnetic hybrid nanogels for insulin delivery, cell imaging, and antidiabetic research of dietary supplements.  

PubMed

In this work, the chitosan-based luminescent/magnetic (CLM) nanomaterials were synthesized by direct gelation of chitosan, CdTe and superparamagnetic iron oxide into the hybrid nanogels. The morphology, sizes and properties of the nanogels prepared with different chitosan/QD/MNP ratios and under different processing parameters were researched. Fluorescence microscopy, FTIR spectra and TEM images confirmed the success of the preparation of the CLM hybrid nanogels. Spherical CLM hybrid nanogels with appropriate average sizes (<160 nm) were used for insulin loading. The actual loading amount of insulin was approximately 40.1mg/g. Human normal hepatocytes L02 cell line was used to explore the effects of additives, such as mangiferin (MF), (-)-epigallocatechin gallate (EGCG), and (-)-epicatechin gallate (ECG) on the insulin-receptor-mediated cellular uptake using insulin-loaded CLM (ICLM) hybrid nanogels. Above 80% of viability of L02 cells were watched at a nanogels concentration of 500 ?g/mL whatever the additives existed or not. The study discovered that the fluorescent signals of the ICLM hybrid nanogels in L02 cells were more intense in the presence of MF, EGCG and ECG in medium than in the absence of these components, respectively. These results demonstrate that MF, EGCG and ECG are potentially able to enhance targeting combination of insulin with L02 cells and improve insulin sensitivity in L02 cells. The hybrid nanogels designed as a targeting carrier can potentially offer an approach for integration of insulin delivery, cell imaging, and antidiabetic investigation of dietary supplements. PMID:22342466

Shen, Jian-Min; Xu, Luan; Lu, Yan; Cao, Hui-Ming; Xu, Zhi-Gang; Chen, Tong; Zhang, Hai-Xia

2012-02-07

378

Electrospun chitosan microspheres for complete encapsulation of anionic proteins: controlling particle size and encapsulation efficiency.  

PubMed

Electrospinning was employed to fabricate chitosan microspheres by a single-step encapsulation of proteins without organic solvents. Chitosan in acetic acid was electrospun toward a grounded sodium carbonate solution at various electric potential and feeding rates. Electrospun microspheres became insoluble and solidified in the sodium carbonate solution by neutralization of chitosan acetate. When the freeze-dried microspheres were examined by scanning electron microscopy, the small particle size was obtained at higher voltages. This is explained by the chitosan droplet size at the electrospinning needle was clearly controllable by the electric potential. The recovery yield of chitosan microspheres was dependent on the concentration of chitosan solution due to the viscosity is the major factor affecting formation of chitosan droplet during curling of the electrospinning jets. For protein encapsulation, fluorescently labeled bovine serum albumin (BSA) was codissolved with chitosan in the solution and electrospun. At higher concentration of sodium carbonate solution and longer solidification time in the solution, the encapsulation efficiency of the protein was confirmed to be significantly high. The high encapsulation efficiency was achievable by instant solidification of microspheres and electrostatic interactions between chitosan and BSA. Release profiles of BSA from the microspheres showed that the protein release was faster in acidic solution due to dissolution of chitosan. Reversed-phase chromatography of the released fractions confirmed that exposure of BSA to acidic solution during the electrospinning did not result in structural changes of the encapsulated protein. PMID:23636817

Choi, Ji Suk; Kim, Younghee; Kang, Jihyun; Jeong, Seo Young; Yoo, Hyuk Sang

2013-04-30

379

Fabrication, mechanical properties, and biocompatibility of graphene-reinforced chitosan composites.  

PubMed

Few-layered graphene sheets, synthesized by direct current arc-discharge method using NH(3) as one of the buffer gases, were dispersed in chitosan/acetic acid solutions. FTIR and X-ray photoelectron spectroscopy showed the presence of oxygen-containing functional groups on the surface of graphene sheets that may assist the good dispersion of graphene in chitosan solution. Graphene/chitosan films were produced by solution casting method. The mechanical properties of composite films were tested by nanoindentation method. With the addition of a small amount of graphene in chitosan (0.1-0.3 wt %), the elastic modulus of chitosan increased over ? 200%. The biocompatibility of graphene/chitosan composite films was checked by tetrazolium-based colorimetric assays in vitro. The cell adhesion result showed that the L929 cell can adhere to and develop on the graphene/chitosan composite films as well as on pure chitosan film, indicating that graphene/chitosan composites have good biocompatibility. Because there is no metallic impurity in graphene raw materials, the time-consuming purification process for removing metal nanoparticles entrapped in carbon nanotubes is thus avoided when graphene is used to prepare biomedical materials. Graphene/chitosan composites are potential candidates as scaffold materials in tissue engineering. PMID:20687549

Fan, Hailong; Wang, Lili; Zhao, Keke; Li, Nan; Shi, Zujin; Ge, Zigang; Jin, Zhaoxia

2010-09-13

380

Antimicrobial Actions of Degraded and Native Chitosan against Spoilage Organisms in Laboratory Media and Foods  

PubMed Central

The objective of this study was to determine whether chitosan (poly-?-1,4-glucosamine) and hydrolysates of chitosan can be used as novel preservatives in foods. Chitosan was hydrolyzed by using oxidative-reductive degradation, crude papaya latex, and lysozyme. Mild hydrolysis of chitosan resulted in improved microbial inactivation in saline and greater inhibition of growth of several spoilage yeasts in laboratory media, but highly degraded products of chitosan exhibited no antimicrobial activity. In pasteurized apple-elderflower juice stored at 7°C, addition of 0.3 g of chitosan per liter eliminated yeasts entirely for the duration of the experiment (13 days), while the total counts and the lactic acid bacterial counts increased at a slower rate than they increased in the control. Addition of 0.3 or 1.0 g of chitosan per kg had no effect on the microbial flora of houmous, a chickpea dip; in the presence of 5.0 g of chitosan per kg, bacterial growth but not yeast growth was substantially reduced compared with growth in control dip stored at 7°C for 6 days. Improved antimicrobial potency of chitosan hydrolysates like that observed in the saline and laboratory medium experiments was not observed in juice and dip experiments. We concluded that native chitosan has potential for use as a preservative in certain types of food but that the increase in antimicrobial activity that occurs following partial hydrolysis is too small to justify the extra processing involved.

Rhoades, J.; Roller, S.

2000-01-01

381

Adsorption of chitosan onto carbonaceous surfaces and its application: atomic force microscopy study  

NASA Astrophysics Data System (ADS)

The adsorption of chitosan onto highly ordered pyrolytic graphite(HOPG) surfaces and its applications have been studied by atomic force microscopy (AFM). The results indicated that chitosan topography formed on the HOPG surface significantly depends on the pH conditions and its concentration for the incubation. Under strongly acidic conditions (pH < 3.5) and at a concentration of 1 mg ml - 1, chitosan formed into uniform network structures composed of fine chains. When the solution pH was changed from 3.5 to 6.5, chitosan tends to form a thicker film. Under neutral and basic conditions, chitosan changed into spherical nanoparticles, and their sizes were increased with increasing pH. Dendritic structures have been observed when the chitosan concentration was increased up to 5 mg ml - 1. In addition, the chitosan topography can also be influenced by ionic strength and the addition of different metal ions. When 0.1 M metal ions Na + , Mg2 + , Ca2 + and Cu2 + were added into the chitosan solution at pH 3.0 for the incubation, network structures, branched chains, block structures and dense networks attached with many small particles were observed, respectively. The potential applications of these chitosan structures on HOPG have been explored. Preliminary results characterized by AFM and XPS indicated that the chitosan network formed on the HOPG surface can be used for AFM lithography, selective adsorption of gold nanoparticles and DNA molecules.

Tan, Shengnan; Liu, Zhiguo; Zu, Yuangang; Fu, Yujie; Xing, Zhimin; Zhao, Lin; Sun, Tongze; Zhou, Zhen

2011-04-01

382

Effects of laminin-coated carbon nanotube/chitosan fibers on guided neurite growth.  

PubMed

This study assesses the ability and potential of carbon nanotube (CNT)/chitosan to guide axon re-growth after nerve injuries. The CNT/chitosan fibers were produced via the coagulation and hydrodynamic focusing method. Fiber width and morphology were adjusted using such parameters as syringe pumping rate and the coagulant used. The CNT/chitosan fiber diameters were 50-300 ?m for syringe pumping rates of 6-48 mL/h. Polyethylene glycol/NaOH (25%, w/w) solution was a suitable coagulant for forming fibers with small diameters. Physical property tests demonstrate that the CNT/chitosan composites had superior tensile strength and electrical conductivity compared with those of chitosan alone. The MTT and LDH tests reveal that CNT/chitosan composites were not cytotoxic. To improve the neural cell affinity of CNT/chitosan fibers, laminin was incorporated onto fiber surfaces via the oxygen plasma technique; cell adhesion ratio increased significantly from 3.5% to 72.2% with this surface modification. Immunofluorescence staining and SEM imaging indicate that PC12 cells adhered successfully and grew on the laminin (LN)-coated CNT/chitosan films and fibers. Experimental results show that PC12 grown on LN-coated CNT/chitosan fibers in vitro extend longitudinally oriented neurites in a manner similar to that of native peripheral nerves. With the inherent electrical properties of CNTs, oriented CNT/chitosan fibers have a potential for use as nerve conduits in nerve tissue engineering. PMID:21800418

Huang, Yi-Cheng; Hsu, Sung-Hao; Kuo, Wen-Chun; Chang-Chien, Cheng-Lun; Cheng, Henrich; Huang, Yi-You

2011-07-28

383

Adsorption of chitosan onto carbonaceous surfaces and its application: atomic force microscopy study.  

PubMed

The adsorption of chitosan onto highly ordered pyrolytic graphite(HOPG) surfaces and its applications have been studied by atomic force microscopy (AFM). The results indicated that chitosan topography formed on the HOPG surface significantly depends on the pH conditions and its concentration for the incubation. Under strongly acidic conditions (pH < 3.5) and at a concentration of 1 mg ml?¹, chitosan formed into uniform network structures composed of fine chains. When the solution pH was changed from 3.5 to 6.5, chitosan tends to form a thicker film. Under neutral and basic conditions, chitosan changed into spherical nanoparticles, and their sizes were increased with increasing pH. Dendritic structures have been observed when the chitosan concentration was increased up to 5 mg ml?¹. In addition, the chitosan topography can also be influenced by ionic strength and the addition of different metal ions. When 0.1 M metal ions Na+, Mg²+, Ca²+ and Cu²+ were added into the chitosan solution at pH 3.0 for the incubation, network structures, branched chains, block structures and dense networks attached with many small particles were observed, respectively. The potential applications of these chitosan structures on HOPG have been explored. Preliminary results characterized by AFM and XPS indicated that the chitosan network formed on the HOPG surface can be used for AFM lithography, selective adsorption of gold nanoparticles and DNA molecules. PMID:21389576

Tan, Shengnan; Liu, Zhiguo; Zu, Yuangang; Fu, Yujie; Xing, Zhimin; Zhao, Lin; Sun, Tongze; Zhou, Zhen

2011-03-10

384

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

PubMed

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

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

385

The calcium-dependent regulation of spheroid formation and cardiomyogenic differentiation for MSCs on chitosan membranes.  

PubMed

Mesenchymal stem cells (MSCs) were recently found to form three-dimensional (3D) multicellular spheroids on chitosan membranes. The exact mechanism of spheroid formation, however, remains unclear. In this study, the regulation of spheroid formation for adipose derived adult stem cells (ADAS) grown on chitosan membranes was examined. By varying the membrane thickness, calcium concentration in culture medium, and acetylation extent of chitosan, the physico-chemical characteristics of chitosan that modulated spheroid formation was elucidated. The capacity of cardiomyogenic differentiation was further evaluated. Results suggested that the calcium binding capacity of chitosan may affect the cell-substrate and cell-cell interactions and critically influence the dynamics of spheroid formation. The intracellular calcium level was elevated for ADAS spheroids on chitosan. Chitosan-bound calcium was observed to enter the cells. The expression of N-cadherin was upregulated for ADAS spheroids on chitosan, evidenced by quantitative RT-PCR and Western blot. After the induction by 5-aza, the expression levels of cardiac marker genes (Gata4, Nkx2.5, Tnnt2, and Myh6) were remarkably enhanced (about four-fold) for ADAS on chitosan vs. tissue culture polystyrene or polyvinyl alcohol. Immunofluorescence staining confirmed the expression of cardiac-associated tight junction protein ZO-1 for ADAS grown on chitosan membranes. The gene expression of Wnt11 was significantly upregulated for ADAS spheroids on chitosan at 3 days and 12 days. We suggested that Wnt11 may be involved in the spheroid formation and cardiomyogenic differentiation of MSCs on chitosan membranes. Spheroids formed on the acetylated chitosan or polyvinyl alcohol membranes failed to show such behavior. The properties of MSC spheroids were therefore determined by the culture substrate. PMID:22985995

Yeh, Hsi-Yi; Liu, Bing-Hsien; Hsu, Shan-Hui

2012-09-15

386

FUNGAL CHITOSAN EXTRACTS ARE AS EFFECTIVE IN REDUCING DECAY CAUSED BY BOTRYTIS CINEREA, PENICILLIUM EXPANSUM, AND PENICILLIUM SOLITUM AS COMMERCIAL SEASHELL CHITOSAN EXTRACTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

'Golden Delicious' apples were surface disinfested or disinfected insects with 70% ethanol and wounded once towards the top of each apple. Two % chitosan solutions in sterile deionized water were adjusted to pH 6 with sodium hydroxide or acetic acid. Five chitosan extract solutions were utilized as...

387

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

2010-01-18

388

Polypyrrol\\/chitosan hydrogel hybrid microfiber as sensing artificial muscle  

Microsoft Academic Search

An electrochemical actuator demands that it should act as a sensor of the working conditions for its efficient application in devices. Actuation and sensing characteristics of a biopolymer\\/conducting polymer hybrid microfiber artificial muscle fabricated through wet spinning of a chitosan solution followed by in situ chemical polymerization with pyrrol employing bis(triflouro methane sulfonyl) imide as dopant and ferric chloride as

Yahya A. Ismail; Jose G. Martínez; Ahmad S. Al Harrasi; Seon J. Kim; Toribio F. Fernández Otero

2011-01-01

389

Ionically and covalently crosslinked hydrogels based on gelatin and chitosan  

Microsoft Academic Search

The formation of double crosslinked (ionic and covalent) gelatin (G) and chitosan (CS) hydrogels was studied. The covalent crosslinking consists in the reaction between the carbonyl groups of glutaraldehyde with the free amine groups from the two polymers; the ionic crosslinking is based on sulphate anions interaction with protonated amine groups of the polymers solubilised in acetic acid. The structural

A. N. J?tariu; M. Danu; C. A. Peptu; G. Ioanid; C. Ibanescu; M. Popa

2011-01-01

390

The use of chitosan to damage Cryptococcus neoformans biofilms  

Microsoft Academic Search

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.

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

2010-01-01

391

Physiology of microbial degradation of chitin and chitosan  

Microsoft Academic Search

Chitin is produced in enormous quantities in the biosphere, chiefly as the major structural component of most fungi and invertebrates. Its degradation is chiefly by bacteria and fungi, by chitinolysis via chitinases, but also via deacetylation to chitosan, which is hydrolysed by chitosanases. Chitinases and chitosanases have a range of roles in the organisms producing them: autolytic, morphogenetic or nutritional.

Graham W. Gooday

1990-01-01

392

Chitosan as a novel nasal delivery system for vaccines  

Microsoft Academic Search

A variety of different types of nasal vaccine systems has been described to include cholera toxin, microspheres, nanoparticles, liposomes, attenuated virus and cells and outer membrane proteins (proteosomes). The present review describes our work on the use of the cationic polysaccharide, chitosan as a delivery system for nasally administered vaccines. Several animal studies have been carried out on influenza, pertussis

L Illum; I Jabbal-Gill; M Hinchcliffe; A. N Fisher; S. S Davis

2001-01-01

393

Vanadium (IV) sorption by chitosan: Kinetics and equilibrium  

Microsoft Academic Search

The adsorption of vanadium (IV) by chitosan, a naturally occurring material, is studied according to equilibrium and kinetics. Sorption isotherms are determined and single mechanisms of diffusion are studied. These are regarded as the main limiting steps. The parameters studied are: pH, the initial metal concentration, the particle size of the polymer and the stirring speed. While the fourth parameter

M. Jansson-Charrier; E. Guibal; J. Roussy; B. Delanghe; P. Le Cloirec

1996-01-01

394

Relationship between physicochemical characteristics and functional properties of chitosan  

Microsoft Academic Search

In order to select an ideal chitosan (CS) species as a material for implantation vehicle to control drug release in the body, the relationship between physicochemical characteristics (including molecular weight, degree of deacetylation, and viscosity) and functional properties (including ability to form spherical gel, control of drug release from CS gel, and biodegradation of CS) was investigated for various CS.

Kyoko Kofuji; Chun-Jun Qian; Masumi Nishimura; Ikumi Sugiyama; Yoshifumi Murata; Susumu Kawashima

2005-01-01

395

Structure and antimicrobial activities of benzoyl phenyl-thiosemicarbazone-chitosans.  

PubMed

Previously, we had prepared acetyl phenyl-thiosemicarbazone derivatives of chitosan, and their antimicrobial activities were analyzed. The purpose of the present study was to further assess the relationship between the structure and antimicrobial activities of benzoyl phenyl-thiosemicarbazone-chitosan. Ten new benzoyl phenyl-thiosemicarbazone-chitosans were prepared and their structures were characterized by FT-IR and elemental analysis. The antimicrobial experiment against four species of bacteria and four crop-threatening pathogenic fungi were conducted based on the derivatives of chitosan with different molecular weight at different concentrations. The results indicated that the antimicrobial activities of benzoyl phenyl-thiosemicarbazone derivatives are much better than that of pure CS. The value of the minimum inhibition concentration (MIC) and the minimum bactericidal concentration (MBC) of the derivatives against Escherichia coli was 7.03 and 225 ?g mL(-1) respectively. All of the derivatives had significant inhibiting effect on the investigated fungi in the concentration of 50-500 ?g mL(-1), and the maximum inhibitory index was 94.74%. These results indicate that the derivatives have potential ability used as antibacterial reagent in agricultural field. PMID:22266384

Zhong, Zhimei; Aotegen, Bayaer; Xu, Hui; Zhao, Shuang

2012-01-14

396

Novel in Vitro Efficiency of Chitosan Biomolecule against Trichomonas gallinae  

PubMed Central

Background Development of new natural agents for parasitic diseases treatment has unexpectedly increased to overcome effectively against emergence and re-emergence of parasitic diseases, the appearance of drug resistant organisms and toxic side effects of current agents. The aim of the study was to evaluate antiprotozoal activities of chitosan biomolecule on trophozoites of Trichomonas gallinae. Methods The antitrichomonal activity of various low molecular weight chitosan concentrations including 125, 250, 500 and 1250 µg ml?1 against T. gallinae trophozoites cultured in trypticase-yeast extract-maltose medium supplemented with heat-inactivated cold horse serum was evaluated in vitro. Samples containing medium without chitosan were also assayed as controls. Results The mortality rates at 0, 3 and 6 h post treatment with all concentrations were significantly different from control group (P<0.05). Treated trophozoites showed more susceptibility to the highest concentration reaching mortality rate of 100% at 3h post inoculation. However, at this time, results for 125, 250 and 500 µg ml?1 were 93%, 95% and 96.7%, respectively. Conclusion The results demonstrate that the application of chitosan biomolecule is a promising option for treatment of trichomoniasis in pigeons.

Tavassoli, M; Imani, A; Tajik, H; Moradi, M; Pourseyed, SH

2012-01-01

397

Antioxidant protection of human serum albumin by chitosan.  

PubMed

Inhibition of protein oxidation by reactive oxygen species (ROS) would confer benefit to living organisms exposed to oxidative stress, because oxidized proteins are associated with many diseases and can propagate ROS-induced damage. We measured the ability of 2800Da chitosan, D-glucosamine and N-acetyl glucosamine to protect human serum albumin from oxidation by peroxyl radicals derived from 2,2'-azobis(2-amidinopropane)dihydrochloride and N-centered radicals from 1,1'-diphenyl-2-picrylhydrazyl and from 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid). Comparison with the antioxidant action of vitamin C showed that, on a molar basis, chitosan was equally effective in preventing formation of carbonyl and hydroperoxide groups in human serum albumin exposed to peroxyl radicals. It was also a potent inhibitor of conformational changes in the protein, assessed by absorption spectrum and intrinsic fluorescence. D-glucosamine was much less effective and N-acetyl glucosamine was not a useful antioxidant. Protection of the albumin from peroxyl radicals was achieved by scavenging of peroxyl radical. Chitosan was also a good scavenger of N-centered radicals, with glucosamine and N-acetyl glucosamine much less effective. The results suggest that administration of low molecular weight chitosans may inhibit neutrophil activation and oxidation of serum albumin commonly observed in patients undergoing hemodialysis, resulting in reduction of oxidative stress associated with uremia. PMID:18514811

Anraku, Makoto; Kabashima, Mikie; Namura, Hitomi; Maruyama, Toru; Otagiri, Masaki; Gebicki, Janusz M; Furutani, Nobuko; Tomida, Hisao

2008-04-16

398

A Chitosan Induced 9-Lipoxygenase in Adelostemma gracillimum Seedlings  

PubMed Central

Oxylipins generated by the lipoxygenase (LOX) pathway play an important role in plant defense against biotic and abiotic stress. In chitosan-treated Adelostemma gracillimum seedlings, obvious accumulation of 9-LOX-derived oxylipins, namely 9,10,11-trihydroxy-12-octadecenoic acid, was detected. Using degenerate primers, a LOX-specific fragment putatively encoding LOX was obtained by RT-PCR, and a 2.9-kb full-length cDNA named AgLOX1 was isolated by RACE from chitosan-induced A. gracillimum seedlings. Genomic Southern analysis implied that there was only one copy of AgLOX1 in the A. gracillimum genome. AgLOX1 was expressed in Escherichia coli and the recombinant protein was partially purified. The enzyme converted linoleic and linolenic acids almost exclusively to their 9-hydroperoxides. AgLOX1 encoded a 9-lipoxygenase. Northern blot analysis indicated that chitosan-induced AgLOX1 transcript accumulation peaked at 8 h after initiation of treatment, whereas trihydroxy derivatives accumulation was highest at 24 h after elicitation. Results showed that chitosan-induced AgLOX1 encoded a 9-lipoxygenase potentially involved in the defense response through 9-LOX pathway leading to biosynthesis of antimicrobial compounds in A. gracillimum seedlings.

Li, Jing; Zhao, Pei-Ji; Ma, Chang-Le; Zeng, Ying

2012-01-01

399

Fish oil encapsulation with chitosan using ultrasonic atomizer  

Microsoft Academic Search

An encapsulation technique was developed using an ultrasonic atomizer and three processing steps: emulsification, ultrasonic atomization, and freeze drying. Emulsion preparation variables such as concentration of wall materials [chitosan (CS), maltodextrin (MD) and whey protein isolate (WPI)] and tuna oil were optimized. The size and stability of the emulsion droplet and the properties of the encapsulated powders after freeze drying

Wanwimol Klaypradit; Yao-Wen Huang

2008-01-01

400

Tailorable Trimethyl chitosans as adjuvant for intranasal immunization  

Microsoft Academic Search

Tailorable Trimethyl Chitosans as Adjuvant for Intranasal Immunization Active vaccination has proven to be the most (cost) effective tool in the fight against infectious diseases. Nowadays, most vaccines are administered via parenteral injection. However, the risk of contaminated needles and need for trained personnel have risen interest in alternative immunization routes. As live attenuated vaccines raise considerable safety issues, (nasal)

R. J. Verheul

2010-01-01

401

Study of growth of calcium carbonate crystals on chitosan film  

Microsoft Academic Search

Biomimetic heterogeneous nucleation and growth of calcium carbonate crystals on the chitosan film as the template took place in supersaturated calcium bicarbonate solution. The specimen were characterized by optical microscopy, scanning electron microscopy, X-ray diffraction, attenuated total reflectance infrared spectroscopy. The obtained crystals proved to be calcite in sheets composed of fine crystal particles. Lab results indicated that proper additives

Fengying Zhang; Jie Wang; Zhengchi Hou; Ming Yu; Leidong Xie

2006-01-01

402

Immobilization of horseradish peroxidase on modified chitosan beads  

Microsoft Academic Search

A method has been developed to immobilize horseradish peroxidase (HRP) on modified chitosan beads by means of graft copolymerization of polyethylacrylate in presence of potassium persulphate and Mohr's salt redox initiator. The activity of free and immobilized HRP was studied. FTIR spectroscopy and scanning electron microscopy were used to characterize HRP immobilization. The efficiency of the immobilization was investigated by

M. Monier; D. M. Ayad; Y. Wei; A. A. Sarhan

2010-01-01

403

Chitosan Clad Manganese Doped Zinc Suiphide Nanoparticles as Biological Labels  

Microsoft Academic Search

Here the authors report the synthesis in aqueous media of redispersible zinc sulphide quantum dots doped with manganese, capped by biocompatible 'chitosan' molecules. The nanoparticles show highly efficient luminescence with a peak at around 590 nm that has been correlated to the manganese dopants. The synthesis involves very simple precipitation techniques that may lead to the development of a cost

H. C. Warad; C. Thanachayanont; G. Tumcharern; J. Dutta

2007-01-01

404

pH-responsive mechanism of a deoxycholic acid and folate comodified chitosan micelle under cancerous environment.  

PubMed

Smart pH-responsive polymeric micelles have attracted much attention as one of the most promising drug delivery candidates. In this paper, a different substitution of deoxycholic acid (DCA) and folic acid (FA) comodified hydroxypropyl chitosans (HPCHS) were synthesized for doxorubicin (DOX) targeted delivery and controllable release. The results indicate that the DOX-release behavior is pH-responsive and closely related with the grafting proportions of the two hydrophobic ingredients. The pH-responsive mechanism for the optimized (6%DCA)-HPCHS-(0.1%FA) was suggested, resulting from a synergistic effect of gradual hydrolysis of the amido bond and electrostatic repulsion between the subsequently protonated DOX and the amino residue of the chitosan backbone under a cancerous microenvironment. Moreover, the DOX/(6%DCA)-HPCHS-(0.1%FA) micelle as a promising targeted drug delivery system in cancer therapy was evaluated by cell growth inhibition assays and confocal laser microscopy in vitro. The results clearly demonstrate a controlled release of its cargo and promoted curative efficacy of DOX. PMID:23311609

Chen, Daiqin; Song, Peng; Jiang, Feng; Meng, Xiangyue; Sui, Weiping; Shu, Chunying; Wan, Li-Jun

2013-01-23

405

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

PubMed

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

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

2010-09-01

406

Eugenol-loaded chitosan nanoparticles: II. Application in bio-based plastics for active packaging.  

PubMed

The aim of the present research was to study the possibility of using eugenol-loaded chitosan nanoparticles as antioxidants for active bio-based packaging material. Eugenol-loaded chitosan nanoparticles were incorporated into thermoplastic flour (TPF) - a model bio-based plastic - through an extrusion process at temperatures above 150°C. The influences of eugenol-loaded chitosan nanoparticles on crystallinity, morphology, thermal properties, radical scavenging activity, reducing power, tensile properties and barrier properties of TPF were investigated. Although the incorporation of 3% (w/w) of eugenol-loaded chitosan nanoparticles significantly reduced the extensibility and the oxygen barrier property of TPF, it provided antioxidant activity and improved the water vapor barrier property. In addition, TPF containing eugenol-loaded chitosan nanoparticles exhibited superior radical scavenging activity and stronger reducing power compared with TPF containing naked eugenol. The results suggest the applicability of TPF containing eugenol-loaded chitosan nanoparticles as an antioxidant active packaging material. PMID:23768604

Woranuch, Sarekha; Yoksan, Rangrong

2012-10-11

407

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

2013-06-26

408

pH- and voltage-responsive chitosan hydrogel through covalent cross-linking with catechol.  

PubMed

A new method for covalently cross-linking chitosan is developed by chemically oxidizing catechol to o-quinone which subsequently reacts with and cross-links chitosan through Michael addition and Schiff base formation. The cross-linked chitosan film shows a pH-responsive, switchlike behavior toward the negatively charged redox probe, Fe(CN)(6)(3-/4-), and withstands harsh acidic conditions. The negative Fe(CN)(6)(3-/4-) is found to be trapped and enriched in the catechol-cross-linked chitosan film under acidic conditions and released into solution by either increasing pH or applying a negative voltage. Chitosan films made with different techniques, i.e., solvent evaporation (simple deposition), electrodeposition, and covalent cross-linking, are examined using cyclic voltammetry and electrochemical impedance spectroscopy (EIS), and the results demonstrate that fabrication methods greatly affect the properties of the chitosan films. PMID:22229705

Zhang, Yongchao; Thomas, Yanique; Kim, Eunkyoung; Payne, Gregory F

2012-01-24

409

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

2012-10-06

410

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

2012-12-31

411

Preparation, characterization and antibacterial properties against E. coli K88 of chitosan nanoparticle loaded copper ions  

NASA Astrophysics Data System (ADS)

The present study was conducted to prepare and characterize chitosan nanoparticle loaded copper ions, and evaluate their antibacterial activity. Chitosan nanoparticles were prepared based on ionotropic gelation, and then the copper ions were loaded. The particle size, zeta potential and morphology were determined. Antibacterial activity was evaluated against E. coli K88 by determination of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) in vitro. Results showed that the antibacterial activity was significantly enhanced by the loading of copper ions compared to those of chitosan nanoparticles and copper ions. The MIC and MBC of chitosan nanoparticle loaded copper ions were 21 times and 42 times lower than those of copper ions, respectively. To confirm the antibacterial mechanism, morphological changes of E. coli K88 treated by chitosan nanoparticle loaded copper ions were dynamically observed with an atomic force microscope (AFM). It was found that chitosan nanoparticle loaded copper ions killed E. coli K88 through damage to the cell membrane.

Du, Wen-Li; Xu, Ying-Lei; Xu, Zi-Rong; Fan, Cheng-Li

2008-02-01

412

Chitosan and Chitosan\\/Ethylene Oxide-Propylene Oxide Block Copolymer Nanoparticles as Novel Carriers for Proteins and Vaccines  

Microsoft Academic Search

Purpose. The aim of this study was to investigate the interaction between the components of novel chitosan (CS) and CS\\/ethylene oxide-propylene oxide block copolymer (PEO-PPO) nanoparticles and to evaluate their potential for the association and controlled release of proteins and vaccines.

Pilar Calvo; Carmen Remuñan-López; Jose Luis Vila-Jato; María José Alonso

1997-01-01

413

The effect of chitosan molecular weight on the characteristics of spray-dried methotrexate-loaded chitosan microspheres for nasal administration.  

PubMed

In this article, the effect of the chitosan molecular weight (MW) on the characteristics of methotrexate (MTX)-encapsulated non-cross-linked chitosan microspheres was studied. Microspheres composed of low-molecular-weight (LMW, 40,000 Da), medium-molecular-weight (MMW, 480,000 Da) and high-molecular-weight (HMW, 850,000 Da) chitosan with the same degree of deacetylation (96%) were obtained by a simple spray-drying method. The MW of chitosan had a noticeable influence on the size distribution, encapsulation efficiency, micromeritic properties (angle of repose and bulk density), controlled release behavior, and mucoadhesive properties. The entrapment efficiencies were in the range of 90-99%. Spray-dried microspheres had a D(50) value of 3.3-4.9 microm, which was suitable for nasal insufflations. The microspheres with LMW chitosan have the best flowability and highest bulk density but were found to be poor in terms of adhesion and in controlling the release behavior of MTX. The MMW chitosan microspheres exhibited the strongest adhesion to the mucosal surface, and the angle of repose values were between 34 and 47 degrees. They could control the release rate by modifying the drug/polymer ratios. Microspheres with HMW chitosan exhibited a lower adhesion than MMW chitosan and a lower release rate of MTX. The physical state of MTX in the chitosan matrix was studied by differential scanning calorimetry, which indicated the presence of a solid dispersion of the amorphous drug in the chitosan matrix. Nasal ciliotoxity showed only minor cilia irritation due to the microspheres, and consequently, they are suitable for nasal drug delivery. PMID:18951272

Sun, Yu; Cui, Fude; Shi, Kai; Wang, Jiamiao; Niu, Mengmeng; Ma, Ruijing

2009-03-01

414

Preparation of Interconnected Porous Chitosan Scaffolds by Sodium Acetate Particulate Leaching  

Microsoft Academic Search

For tissue-engineering applications, a 3D porous chitosan scaffold was simply prepared from a mixture of acidic chitosan solution and sodium acetate particles as the porogen by a salt-leaching method. Differences in the porous structure in terms of pore morphology and interconnectivity between the salt-leached chitosan scaffold and phase-separated scaffold as the control were examined by using scanning electron microscopy, protein

Jin Ik Lim; Yong-Keun Lee; Jeon-Soo Shin; Kook-Jin Lim

2011-01-01

415

Study on the Blending Solution Behavior and Membrane Properties of Sodium Alginate and Chitosan  

Microsoft Academic Search

The rheological behavior of chitosan, sodium alginate and their blends at several composition (2\\/8, 4\\/6, 5\\/5, 6\\/4, 8\\/2 ) has been studied. The chitosan-alginate complex films have been prepared here by blending. Intermolecular interactions in chitosan-alginate complex films have been examined by Fourier transform infrared spectroscopy (FT-IR), viscometry, mechanical measurements. It was found that the -OH , the -NH2 groups,

Xin Meng; Feng Tian; Fan Li; Nan Xing; Jian Yang

2009-01-01

416

The effect of topology of chitosan biomaterials on the differentiation and proliferation of neural stem cells  

Microsoft Academic Search

Neural stem cells (NSCs) are capable of self-renewal and differentiation into three principle central nervous system cell types under specific local microenvironments. Chitosan films (Chi-F), chitosan porous scaffolds (Chi-PS) and chitosan multimicrotubule conduits (Chi-MC) were used to investigate their effects on the differentiation and proliferation of NSCs isolated from the cortices of fetal rats. In the presence of 10% fetal

Gan Wang; Qiang Ao; Kai Gong; Aijun Wang; Lu Zheng; Yandao Gong; Xiufang Zhang

2010-01-01

417

In vitro biomineralization of glutaraldehyde crosslinked chitosan\\/glutamic acid films  

Microsoft Academic Search

In vitro biomineralization of glutaraldehyde crosslinked chitosan\\/glutamic acid films were studied. IR and ESCA (electron\\u000a spectroscopy for chemical analysis) determinations confirm that chitosan and glutamic acid are successfully crosslinked by\\u000a glutaraldehyde to form chitosan-glutamic acid surfaces. Composite films were soaked in saturated Ca(OH)2 solution for 8 d and then immersed in simulated body fluid (SBF) for more than 20 d.

Fang Feng; Yu Liu; Binyuan Zhao; Keao Hu

2009-01-01

418

In vitro characterization of chitosan–gelatin scaffolds for tissue engineering  

Microsoft Academic Search

Recently, chitosan–gelatin scaffolds have gained much attention in various tissue engineering applications. However, the underlying cell–matrix interactions remain unclear in addition to the scaffold degradation and mechanical characteristics. In this study, we evaluated (i) the degradation kinetics of chitosan and chitosan–gelatin scaffolds in the presence of 10mg\\/L of lysozyme for dimensional stability, weight loss, and pH changes for a period

Yan Huang; Stella Onyeri; Mbonda Siewe; Aliakbar Moshfeghian; Sundararajan V. Madihally

2005-01-01

419

Electrospun chitosan-based nanofiber scaffolds for cardiac tissue engineering applications  

Microsoft Academic Search

The objective of this study was to fabricate 3-dimensional (3D) chitosan nanofiber scaffolds using an electrospinning technique and explore its potential for cardiac tissue engineering. Three culture conditions were tested: cardiomyocytes only, cardiomyocytes-fibroblasts cocultures, and cardiomyocyte-endothelial cells cocultures. The cells were seeded on 2-dimensional (2D) chitosan films and 3D chitosan nanofibers. Cellular morphology and functionality were assessed using immunofluorescent staining

Ali Hussain; George Collins; Cheul H. Cho

2010-01-01

420

Rapid adhesion and proliferation of keratinocytes on the gold colloid\\/chitosan film scaffold  

Microsoft Academic Search

The gold colloid\\/chitosan film scaffold, which could enhance the attached ratio and accelerate proliferation of newborn mice keratinocytes, was fabricated by nanotechnology and self-assembly technology. This nanometer scaffold was characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The keratinocytes were cultured and observed on three different extracellular matrices (ECM): gold colloid\\/chitosan film scaffold, chitosan film and cell

Yi Zhang; Hong He; Wen-Juan Gao; Shuang-Yun Lu; Yang Liu; Hai-Ying Gu

2009-01-01

421

Preparation and physical\\/electrochemical characterization of carbon nanotube–chitosan modified pencil graphite electrode  

Microsoft Academic Search

In this work, preparation and characterization of single-walled carbon nanotube–chitosan (SWNT–chitosan) modified disposable pencil graphite electrode (PGE) was carried out. Firstly, commercial single-walled carbon nanotube was purified and characterized using thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and energy dispersive analysis of X-ray (EDX) for this purpose. Purified SWNT was mixed with chitosan polymer

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

2010-01-01

422

Preparation and properties of magnetic Fe 3O 4–chitosan nanoparticles  

Microsoft Academic Search

Magnetic Fe3O4–chitosan nanoparticles were prepared by the covalent binding of chitosan (CTS) onto the surface of magnetic Fe3O4 nanoparticles which were prepared by hydrothermal method using H2O2 as an oxidizer. Transmission electron microscopy (TEM) showed that Fe3O4 particles and Fe3O4–chitosan nanocomposites were regular sphere with a mean diameter of 23nm and 25nm, respectively. X-ray diffraction patterns (XRD) indicated that the

Gui-yin Li; Yu-ren Jiang; Ke-long Huang; Ping Ding; Jie Chen

2008-01-01

423

Investigation on dyeability of polypropylene fabrics grafted with chitosan after plasma modification  

NASA Astrophysics Data System (ADS)

In this study, the properties of polypropylene fabrics grafted with chitosan after being activated by low temperature plasmas were evaluated. The chitosan was applied to polypropylene fabrics by using pad-dry cure technique. The surface morphology was characterized by SEM images. Treated samples were characterized by means of Fourier transform infrared (FTIR) spectroscopy. The polypropylene fabric treated with chitosan demonstrates an excellent dyeability property.

Shahidi, Sheila; Moazzenchi, Bahareh; Ghoranneviss, Mahmood; Azizi, Samar

2013-04-01

424

Accelerating effects of chitosan for healing at early phase of experimental open wound in dogs  

Microsoft Academic Search

Chitosan is a polymeric ?(1?4) glucosamine (2-amino-2-deoxy-d-glucose) and N-acetyl-d-glucosamine (2-acetamido-2-deoxy-d-glucose) which has been reported as a wound healing accelerator. In order to evaluate the efficacy of chitosan as an accelerator of wound healing, experimental open skin wounds were made on the dorsal side in three normal beagles. Cottonfiber-type chitosan (degree of acetylation=18%) was applied for 15 days, and the process

Hiroshi Ueno; Haruo Yamada; Ichiro Tanaka; Naoki Kaba; Mitsunobu Matsuura; Masahiro Okumura; Tsuyoshi Kadosawa; Toru Fujinaga

1999-01-01

425

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

426

Adsorption behavior of reactive dye in aqueous solution on chemical cross-linked chitosan beads  

Microsoft Academic Search

A batch system was applied to study the adsorption of reactive dye (reactive red 189) from aqueous solutions by cross-linked chitosan beads. The ionic cross-linking reagent sodium tripolyphosphate was used to obtain more rigid chitosan beads. To stabilize chitosan in acid solutions, chemical cross-linking reagent epichlorohydrin (ECH), glutaraldehyde and ethylene glycol diglycidyl ether was used and ECH shows a higher

M. S Chiou; H. Y Li

2003-01-01

427

Determination of degree of deacetylation of chitosan by 1 H NMR spectroscopy  

Microsoft Academic Search

This paper describes a novel method to determine the degree of deacetylation of chitosan by 1H NMR spectroscopy. Measurements were carried out at 70°C by using 2 wt% CD3COOD\\/D2O and 2 wt% DC1\\/D2O as solvents for chitosan. In the case of DC1\\/D2O system, effect on hydrolysis of chitosan should be taken into consideration, and the pulse repetition delay required for

Asako Hirai; Hisashi Odani; Akio Nakajima

1991-01-01

428

Effect of chitosan with absorbable collagen sponge carrier on bone regeneration in rat calvarial defect model  

Microsoft Academic Search

The purpose of this study is to evaluate the effect of chitosan with absorbable collagen sponge (ACS) carrier on bone formation in the rat calvarial defect model. New bone area and defect closure of the chitosan\\/ACS group were significantly greater than those of the others at 8 weeks postsurgery (p<0.01). Chitosan reconstituted with ACS has significant potential to induce the

Ui-Won Jung; Soo-Kyoung Kim; Chang-Sung Kim; Kyoo-Sung Cho; Chong-Kwan Kim; Seong-Ho Choi

2007-01-01