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1

Galactosylated poly(ethylene glycol)-chitosan-graft-polyethylenimine as a gene carrier for hepatocyte-targeting  

Microsoft Academic Search

Chitosan and chitosan derivatives have been proposed as alternative and biocompatible cationic polymers for non-viral 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 applications. In the present study a chitosan derivative, galactosylated poly(ethylene glycol)-chitosan-graft-polyethylenimine (Gal-PEG-CHI-g-PEI), was investigated as a potential hepatocyte-targeting gene

Hu-Lin Jiang; Jung-Taek Kwon; Eun-Mi Kim; You-Kyoung Kim; Rohidas Arote; Dhananjay Jere; Hwan-Jeong Jeong; Mi-Kyeong Jang; Jae-Woon Nah; Cheng-Xiong Xu; In-Kyu Park; Myung-Haing Cho; Chong-Su Cho

2008-01-01

2

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

2013-07-01

3

Targeting silymarin for improved hepatoprotective activity through chitosan nanoparticles  

PubMed Central

Introduction: Silymarin is one of the best known hepatoprotective drugs, which is obtained from the seeds of Silybum marianum L., Family: Asteraceae or Compositae. The plant has traditionally been used for centuries as a natural remedy for liver and biliary tract diseases. The aim of the present investigation was to enhance the hepatoprotective activity of silymarin by incorporating it in chitosan (Ch) nanoparticles (NPs) for passive targeted delivery, thereby prolonging its retention time. Materials and Methods: Silymarin loaded NPs were prepared by ionic gelation technique, which were then optimized using a central composite design in order to minimize the particle size and maximize the drug entrapment efficiency. The optimized formulation was evaluated for in vitro drug release study and in vitro study on Swiss Albino mice using carbon tetrachloride (CCL4) induced hepatotoxicity model. Results: In vitro dissolution studies illustrated sustained, zero order drug release from optimized formulation; also its therapeutic potential was amplified during in vitro studies on Swiss Albino mice using CCL4 induced hepatotoxicity model. Conclusion: The results suggested that NPs of silymarin could successfully enhance its hepatoprotective effect by passive targeting and sustained release. PMID:25426436

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

2014-01-01

4

Chitosan\\/pshRNA plasmid nanoparticles targeting MDR1 gene reverse paclitaxel resistance in ovarian cancer cells  

Microsoft Academic Search

Summary  In order to investigate the effect of chitosan\\/pshRNA plasmid nanoparticles targeting MDR1 genes on the resistance of A2780\\/TS\\u000a cells to paclitaxel, chitosan\\/pshRNA plasmid nanoparticles were synthesized by means of a complex coacervation technique and\\u000a transfected into A2780\\/TS cells. The cells transfected with MDR1-targeted chitosan\\/pshRNA plasmid nanoparticles were experimental\\u000a cells and the cells transfected with chitosan\\/pGPU6\\/GFP\\/Neo no-load plasmid nanoparticles served as

Yan Yang; Zehua Wang; Minfang Li; Shi Lu

2009-01-01

5

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

PubMed

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

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

2014-10-01

6

Functional single-walled carbon nanotubes/chitosan conjugate for tumor cells targeting  

NASA Astrophysics Data System (ADS)

The application of single-walled carbon nanotubes (SWCNTs) in the field of biomedicine is becoming an exciting topic because of their flexible structure and propensity for chemical functionalization. In this assay, a novel noncovalently functional SWCNTs based on a natural biocompatible polymer chitosan has been developed for tumor cells targeting. First, SWCNTs were modified by chitosan (CHIT-SWCNT). Second, CHIT-SWCNT was coupled with fluorescein isothiocyanate (FITC), based on the reaction between the isothiocyanate group of FITC and the primary amino group of chitosan. Third, the FITC functionalized CHIT-SWCNT was conjugated with folic acid (FA) after activation with EDC/NHS, based on the reaction between the NHS group of FA and the primary free amino group of chitosan to construct the functional SWCNT/CHIT conjugate, CHIT-SWCNT-FA. The fluorescence CHIT-SWCNT-FA has been used to detect tumor cells with confocal microscopy imaging technology. Our experimental results indicate that the novel CHIT-SWCNT-FA is soluble and stable in PBS, and it can be readily transported inside tumor cells. Combining the intrinsic properties of carbon nanotubes and the versatility of chitosan, CHIT-SWCNT can be used as potential devices for targeted drug delivery and tumor cell sensing. The proposed assay could provide a feasible alternative to presently available functional SWCNTs in biological applications.

Wu, Baoyan; Ou, Zhongmin; Xing, Da

2009-08-01

7

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

PubMed

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

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

2012-01-01

8

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

PubMed Central

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

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

2012-01-01

9

Glycyrrhetinic acid-modified chitosan\\/poly(ethylene glycol) nanoparticles for liver-targeted delivery  

Microsoft Academic Search

A liver-targeted drug delivery carrier, composed of chitosan\\/poly(ethylene glycol)–glycyrrhetinic acid (CTS\\/PEG–GA) nanoparticles, was prepared by an ionic gelation process, in which glycyrrhetinic acid (GA) acted as the targeting ligand. The formation and characterization of these nanoparticles were confirmed by FT-IR, dynamic light scattering (DLS) and zeta potential measurements. The biodistribution of the nanoparticles was assessed by single-photon emission computed tomography

Qin Tian; Chuang-Nian Zhang; Xiu-Hua Wang; Wei Wang; Wei Huang; Rui-Tao Cha; Chun-Hong Wang; Zhi Yuan; Min Liu; Hai-Ying Wan; Hua Tang

2010-01-01

10

Magnetic chitosan nanoparticles as a drug delivery system for targeting photodynamic therapy  

NASA Astrophysics Data System (ADS)

Photodynamic therapy (PDT) has become an increasingly recognized alternative to cancer treatment in clinic. However, PDT therapy agents, namely photosensitizer (PS), are limited in application as a result of prolonged cutaneous photosensitivity, poor water solubility and inadequate selectivity, which are encountered by numerous chemical therapies. Magnetic chitosan nanoparticles provide excellent biocompatibility, biodegradability, non-toxicity and water solubility without compromising their magnetic targeting. Nevertheless, no previous attempt has been reported to develop an in vivo magnetic drug delivery system with chitosan nanoparticles for magnetic resonance imaging (MRI) monitored targeting photodynamic therapy. In this study, magnetic targeting chitosan nanoparticles (MTCNPs) were prepared and tailored as a drug delivery system and imaging agents for PS, designated as PHPP. Results showed that PHPP-MTCNPs could be used in MRI monitored targeting PDT with excellent targeting and imaging ability. Non-toxicity and high photodynamic efficacy on SW480 carcinoma cells both in vitro and in vivo were achieved with this method at the level of 0-100 µM. Notably, localization of nanoparticles in skin and hepatic tissue was significantly less than in tumor tissue, therefore photosensitivity and hepatotoxicity can be attenuated.

Sun, Yun; Chen, Zhi-long; Yang, Xiao-xia; Huang, Peng; Zhou, Xin-ping; Du, Xiao-xia

2009-04-01

11

Therapeutic targeting of chitosan-PEG-folate-complexed oncolytic adenovirus for active and systemic cancer gene therapy.  

PubMed

Adenovirus (Ad)-based cancer therapies have shown much promise. However, until now, Ad has only been delivered directly to primary tumors because the therapeutic efficacy of systemic delivery is limited by the immune response of the host, short blood circulation times, and non-specific liver uptake of Ad. In order to circumvent the issues regarding systemic delivery and to increase the safety and efficacy of Ad therapies, the surface of oncolytic Ad was coated with cationic polymer chitosan via ionic crosslinking (Ad/chitosan), after which polyethylene glycol (PEG) and/or folic acid (FA) was chemically conjugated onto the surface of Ad/chitosan, generating Ad/chitosan-FA, Ad/chitosan-PEG, and Ad/chitosan-PEG-FA nanocomplex. The FA-coordinated Ad nanocomplexes (Ad/chitosan-FA & Ad/chitosan-PEG-FA) elicited folate receptor (FR)-selective cancer cell killing efficacy. In vivo administration of Ad/chitosan-PEG or Ad/chitosan-PEG-FA into mice demonstrated that PEGylation greatly increased blood circulation time, resulting in 9.0-fold and 48.9-fold increases at 24h after injection compared with naked Ad, respectively. In addition, generation of Ad-specific neutralizing antibodies in mice treated with Ad/chitosan-PEG-FA was markedly decreased by 75.3% compared with naked Ad. The quantitative polymerase chain reaction assay results showed a 285.0-fold increase in tumor tissues and a 378-fold reduction of Ad/chitosan-PEG-FA in liver tissues compared with naked Ad. Bioluminescence imaging study further supported the enhanced tumor-to-liver ratio of Ad/chitosan-PEG-FA. Consequently, systemic delivery of Ad/chitosan-PEG-FA significantly inhibited the growth of FR-positive tumor, decreasing 52.8% compared to the naked Ad-treated group. Importantly, PEGylated oncolytic Ad nanocomplexes showed no elevation of both alanine transaminase and aspartate transaminase levels, demonstrating that systemically delivered Ad-related hepatic damage can be completely eliminated with PEG conjugation. In sum, these results demonstrate that conjugation of chitosan-PEG-FA to oncolytic Ad significantly improves antitumor efficacy and safety profiles, suggesting that Ad/chitosan-PEG-FA has potential as a therapeutic agent to target FR-positive cancer via systemic administration. PMID:23562633

Kwon, Oh-Joon; Kang, Eunah; Choi, Joung-Woo; Kim, Sung Wan; Yun, Chae-Ok

2013-08-10

12

In vitro evaluation of folic acid modified carboxymethyl chitosan nanoparticles loaded with doxorubicin for targeted delivery  

Microsoft Academic Search

The development of smart targeted nanoparticle that can deliver drugs to direct cancer cells, introduces better efficacy and\\u000a lower toxicity for treatment. We report the development and characterizations of pH-sensitive carboxymethyl chitosan modified\\u000a folic acid nanoparticles and manifest their feasibility as an effective targeted drug delivery vehicle. The nanoparticles\\u000a have been synthesized from carboxymethyl chitosan with covalently bonded bifunctional 2,2?-(ethylenedioxy)-bis-(ethylamine)

Sumanta K. Sahu; Sanjay K. Mallick; Susmita Santra; Tapas K. Maiti; Sudip K. Ghosh; Panchanan Pramanik

2010-01-01

13

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

Microsoft Academic Search

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

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

2011-01-01

14

New Lipid and Glycolipid-Based Nanosystems for Targeted Gene Delivery: Cholenims, Glycoclips, Glycolipids and Chitosan  

Microsoft Academic Search

Cationic lipid vesicles and polypeptides represent common non-viral gene delivery systems for in vitro and in vivo applications.\\u000a New non-viral vectors for targeted gene delivery, namely, mono-, di- and tricholesterol derivatives of oligoethyleneimine,\\u000a glycolipids and chitosan derivatives are reported in this chapter. Testing of genotoxicity, cytotoxicity and gene transfer\\u000a activity against transformed monolayer and suspension cell cultures is carried out

R. I. Zhdanov; E. V. Bogdanenko; T. V. Zarubina; S. I. Dominova; G. G. Krivtsov; A. S. Borisenko; A. S. Bogdanenko; G. A. Serebrennikova; Yu. L. Sebyakin; V. V. Vlassov

15

Self-assembling chitosan\\/poly-?-glutamic acid nanoparticles for targeted drug delivery  

Microsoft Academic Search

For the purpose of targeted drug delivery, composite biodegradable nanoparticles were prepared from chitosan and the poly-?-glutamic\\u000a acid via an ionotropic gelation process. These stable self-assembled nanoparticles were characterized by dynamic light scattering,\\u000a transmission electron microscopy, and atomic force microscopy, which demonstrated that the nanosystem consists of spherical\\u000a particles with a smooth surface both in aqueous environment and in dried

Zsolt Keresztessy; Magdolna Bodnár; Elizabeth Ber; István Hajdu; Min Zhang; John F. Hartmann; Tamara Minko; János Borbély

2009-01-01

16

Improvement of therapeutic efficacy of PLGA nanoformulation of siRNA targeting anti-apoptotic Bcl-2 through chitosan coating.  

PubMed

Potential use of siRNA as therapeutic agent has elicited a great deal of interest. However, insufficient cellular uptake and poor stability limited its application in therapeutics. In our earlier study, we prepared PLGA nanoparticles for effective delivery of siRNA targeting Bcl-2 gene to block its expression. Purpose of the present study was to improve effectiveness of PLGA nanoformulation of siRNA targeting anti-apoptotic Bcl-2 gene through chitosan coating. We prepared chitosan coated PLGA nanoparticles by using the double emulsion solvent diffusion (DESE) method. Characterization of prepared chitosan coated nanoformulation was done followed by cytotoxicity studies, expression studies and in vivo studies. Particle size of chitosan coated nanoparticles was found to be increased compared to PLGA nanoparticles from 244 to 319 nm. Surface charge of chitosan coated nanoparticles was found to be positive facilitating transfection of nanoformulation into cells. In vitro studies indicated increased transfection of nanoparticles resulting in effective silencing of Bcl-2. Marked apoptotic lesions were observed in nuclear staining studies. On comparison of the results from the present study with those of previous study, it was found that the extent of silencing of Bcl-2 gene by PLGA nanoformulation has improved significantly through chitosan coating. In vivo studies showed significant tumor regression in animals treated with chitosan coated PLGA nanoformulation of siRNA. PMID:23291045

Jagani, Hitesh Vitthalbhai; Josyula, Venkata Rao; Palanimuthu, Vasanth Raj; Hariharapura, Raghu Chandrashekar; Gang, Sagar Shantimal

2013-03-12

17

Synthesis of Doxorubicin loaded magnetic chitosan nanoparticles for pH responsive targeted drug delivery.  

PubMed

Targeted drug delivery is a promising alternative to overcome the limitations of classical chemotherapy. In an ideal targeted drug delivery system carrier nanoparticles would be directed to the tumor tissue and selectively release therapeutic molecules. As a novel approach, chitosan coated magnetic nanoparticles (CS MNPs) maintain a pH dependent drug delivery which provides targeting of drugs to the tumor site under a magnetic field. Among various materials, chitosan has a great importance as a pH sensitive, natural, biodegradable, biocompatible and bioadhesive polymer. The aim of this study was to obtain an effective targeted delivery system for Doxorubicin, using chitosan coated MNPs. Different sized CS MNPs were produced by in situ synthesis method. The anti-cancer agent Doxorubicin was loaded onto CS MNPs which were characterized previously. Doxorubicin loading was confirmed by FTIR. Drug loading and release characteristics, and stability of the nanoparticles were investigated. Our results showed that the CS MNPs have pH responsive release characteristics. The cellular internalization of Doxorubicin loaded CS MNPs were visualized by fluorescent microscopy. Doxorubicin loaded CS MNPs are efficiently taken up by MCF-7 (MCF-7/S) and Doxorubicin resistant MCF-7 (MCF-7/1 ?M) breast cancer cells, which increases the efficacy of drug and also maintains overcoming the resistance of Doxorubicin in MCF-7/Dox cells. Consequently, CS MNPs synthesized at various sizes can be effectively used for the pH dependent release of Doxorubicin in cancer cells. Results of this study can provide new insights in the development of pH responsive targeted drug delivery systems to overcome the side effects of conventional chemotherapy. PMID:24931189

Unsoy, Gozde; Khodadust, Rouhollah; Yalcin, Serap; Mutlu, Pelin; Gunduz, Ufuk

2014-10-01

18

Mannosylated Chitosan Nanoparticles for Delivery of Antisense Oligonucleotides for Macrophage Targeting  

PubMed Central

The therapeutic potential of antisense oligonucleotides (ASODN) is primarily dependent upon its safe and efficient delivery to specific cells overcoming degradation and maximizing cellular uptake in vivo. The present study focuses on designing mannosylated low molecular weight (LMW) chitosan nanoconstructs for safe ODNs delivery by macrophage targeting. Mannose groups were coupled with LMW chitosan and characterized spectroscopically. Mannosylated chitosan ODN nanoparticles (MCHODN NPs) were formulated by self-assembled method using various N/P ratio (moles of amine groups of MCH to phosphate moieties of ODNs) and characterized for gel retardation assay, physicochemical characteristics, cytotoxicity and transfection efficiency, and antisense assay. Complete complexation of MCH/ODN was achieved at charge ratio of 1:1 and above. On increasing the N/P ratio of MCH/ODN, particle size of the NPs decreased whereas zeta potential (ZV) increased. MCHODN NPs displayed much higher transfection efficiency into Raw 264.7 cells (bears mannose receptors) than Hela cells and no significant toxicity was observed at all MCH concentrations. Antisense assay revealed that reduction in lipopolysaccharide (LPS) induced serum TNF-? is due to antisense activity of TJU-2755 ODN (sequence complementary to 3?-UTR of TNF-?). These results suggest that MCHODN NPs are acceptable choice to improve transfection efficiency in vitro and in vivo. PMID:25057492

Asthana, Abhay; Kohli, Dharm Veer; Vyas, Suresh Prasad

2014-01-01

19

Mannosylated chitosan nanoparticles for delivery of antisense oligonucleotides for macrophage targeting.  

PubMed

The therapeutic potential of antisense oligonucleotides (ASODN) is primarily dependent upon its safe and efficient delivery to specific cells overcoming degradation and maximizing cellular uptake in vivo. The present study focuses on designing mannosylated low molecular weight (LMW) chitosan nanoconstructs for safe ODNs delivery by macrophage targeting. Mannose groups were coupled with LMW chitosan and characterized spectroscopically. Mannosylated chitosan ODN nanoparticles (MCHODN NPs) were formulated by self-assembled method using various N/P ratio (moles of amine groups of MCH to phosphate moieties of ODNs) and characterized for gel retardation assay, physicochemical characteristics, cytotoxicity and transfection efficiency, and antisense assay. Complete complexation of MCH/ODN was achieved at charge ratio of 1:1 and above. On increasing the N/P ratio of MCH/ODN, particle size of the NPs decreased whereas zeta potential (ZV) increased. MCHODN NPs displayed much higher transfection efficiency into Raw 264.7 cells (bears mannose receptors) than Hela cells and no significant toxicity was observed at all MCH concentrations. Antisense assay revealed that reduction in lipopolysaccharide (LPS) induced serum TNF-? is due to antisense activity of TJU-2755 ODN (sequence complementary to 3'-UTR of TNF-?). These results suggest that MCHODN NPs are acceptable choice to improve transfection efficiency in vitro and in vivo. PMID:25057492

Asthana, Gyati Shilakari; Asthana, Abhay; Kohli, Dharm Veer; Vyas, Suresh Prasad

2014-01-01

20

Folate conjugated chitosan grafted thiazole orange derivative with high targeting for early breast cancer cells diagnosis.  

PubMed

The folate receptor (FR) is over-expressed on many solid tumors and has been exploited for targeted delivery of folic acid linked liposomes to cancer cells in vitro. In the present study, we developed a novel folic acid (FA) conjugated chitosan (CTS) grafted thiazole orange (TO) complex (FA-CTS-TO), and the formation can be used to label tumor cells. The structure of TO derivatives was confirmed by (1)H NMR and MS, and the fluorescence probe of FA-CTS-TO complex was confirmed by Fourier transform infrared analysis and Differential thermal analysis. The in vitro and in vivo of FA-CTS-TO complex were tested in breast cancer cells and the results showed a high targeting specificity in tumor cells with FR over-expressed. Such prominent fluorescence properties demonstrate again that FA-CTS-TO complex as a tumor targeting fluorescence probe is appropriate for breast cancer cells. PMID:22752402

Fei, Xue-Ning; Liu, Yin; Li, Chao

2012-11-01

21

Glucose-conjugated chitosan nanoparticles for targeted drug delivery and their specific interaction with tumor cells  

NASA Astrophysics Data System (ADS)

A novel targeted drug delivery system, glucose-conjugated chitosan nanoparticles (GCNPs), was developed for specific recognition and interaction with glucose transporters (Gluts) over-expressed by tumor cells. GC was synthesized by using succinic acid as a linker between glucosamine and chitosan (CS), and successful synthesis was confirmed by NMR and elemental analysis. GCNPs were prepared by ionic crosslinking method, and characterized in terms of morphology, size, and zeta potential. The optimally prepared nanoparticles showed spherical shapes with an average particle size of (187.9 ± 3.8) nm and a zeta potential of (- 15.43 ± 0.31) mV. The GCNPs showed negligible cytotoxicity to mouse embryo fibroblast and 4T1 cells. Doxorubicin (DOX) could be efficiently entrapped into GCNPs, with a loading capacity and encapsulation efficiency of 20.11% and 64.81%, respectively. DOX-loaded nanoparticles exhibited sustained-release behavior in phosphate buffered saline (pH 7.4). In vitro cellular uptake studies showed that the GCNPs had better endocytosis ability than CSNPs, and the antitumor activity of DOX/GCNPs was 4-5 times effectiveness in 4T1 cell killing than that of DOX/CSNPs. All the results demonstrate that nanoparticles decorated with glucose have specific interactions with cancer cells via the recognition between glucose and Gluts. Therefore, Gluts-targeted GCNPs may be promising delivery agents in cancer therapies.

Li, Jing; Ma, Fang-Kui; Dang, Qi-Feng; Liang, Xing-Guo; Chen, Xi-Guang

2014-12-01

22

Cetuximab conjugated O-carboxymethyl chitosan nanoparticles for targeting EGFR overexpressing cancer cells.  

PubMed

Nanoparticle mediated delivery of antineoplastic agents, functionalized with monoclonal antibodies has achieved extraordinary potential in cancer therapy. The objective of this study was to develop a drug delivery system comprising O-carboxymethyl chitosan (O-CMC) nanoparticles, surface-conjugated with Cetuximab (Cet) for targeted delivery of paclitaxel (PTXL) to Epidermal Growth Factor Receptor (EGFR) over-expressing cancer cells. Nanoparticles around 180±35nm and negatively charged were prepared through simple ionic gelation technique. The alamar blue assay indicated that these targeted nanoparticles displayed a superior anticancer activity compared to non-targeted nanoparticles. The nanoformulation triggered enhanced cell death (confirmed by flow cytometry) due to its higher cellular uptake. The selective uptake of Cet-PTXL-O-CMC nanoparticles by EGFR +VE cancer cells (A549, A431 and SKBR3) compared to EGFR -VE MIAPaCa-2 cells confirms the active targeting and delivery of PTXL via the targeted nanomedicine. Cet-PTXL-O-CMC nanoparticles can be used a promising candidate for the targeted therapy of EGFR over expressing cancers. PMID:23499109

Maya, S; Kumar, Lekshmi G; Sarmento, Bruno; Sanoj Rejinold, N; Menon, Deepthy; Nair, Shantikumar V; Jayakumar, R

2013-04-01

23

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. PMID:23190896

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

24

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

PubMed

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

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

2014-08-01

25

Folate-polyethylene glycol conjugated carboxymethyl chitosan for tumor-targeted delivery of 5-fluorouracil.  

PubMed

Targeted drug delivery has been evolving at an increasing rate due to its potential to reduce the minimum effective dose of a drug and its accompanying side effects. It has shown improved therapeutic efficacy at equivalent plasma concentrations; however, the development of effective targeted delivery systems has remained a major task. In this study, a drug carrier was designed and synthesized by conjugation of folate acid (FA) to carboxymethyl chitosan (CMCS) through a polyethylene glycol (PEG) spacer. The resulting conjugates were confirmed by 1H nuclear magnetic resonance and infrared spectroscopy. The cytotoxicity of CMCS and CMCS?5?fluorouracil (5?FU) was determined by a crystal violet stain assay. The potential of CMCS?PEG?FA for use in the targeted delivery of 5?FU was investigated using 3?(4,5?dimethylthiazol?2?yl)?2,5?diphenyltetrazolium bromide analysis in two cell lines, HeLa and A549, which contain different numbers of folate receptors on their surfaces. The MTT results revealed that in HeLa cells, the cytotoxicity of (CMCS?5?FU)?PEG?FU cells is greater compared with CMCS?5?FU, suggesting that folate receptor?mediated endocytosis may affect the cellular uptake efficiency of 5?FU?loaded CMCS?PEG?FA. The CMCS?PEG?FA conjugates presented in this study show promise as carriers for chemotherapeutic agents due to their solubility at physiological pH, efficiency in carrying chemotherapeutic agents, low cytotoxicity and targeting ability. PMID:24469407

Li, Hai-Lang; He, Ya-Xing; Gao, Qian-Hong; Wu, Guo-Zhong

2014-03-01

26

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

27

Galactosylated chitosan– graft–dextran as hepatocyte-targeting DNA carrier  

Microsoft Academic Search

Lactobionic acid bearing galactose group was coupled with chitosan for liver specificity, and dextran was grafted to galactosylated chitosan (GC) for stability in water. Compared to the GC\\/DNA complex, the stability of the galactosylated chitosan–graft–dextran (GCD)\\/DNA complex could be enhanced. The particle size of the GCD\\/DNA complexes decreased as the charge ratio of GCD to DNA increased. Conformational change of

Y. K Park; Y. H Park; B. A Shin; E. S Choi; Y. R Park; T Akaike; C. S Cho

2000-01-01

28

Galactosylated chitosan-graft-polyethylenimine as a gene carrier for hepatocyte targeting  

Microsoft Academic Search

Chitosans have been proposed as alternative, biocompatible cationic polymers for nonviral gene delivery. However, the low transfection efficiency and low specificity of chitosan need to be addressed before clinical application. We prepared galactosylated chitosan-graft-polyethylenimine (GC-g-PEI) copolymer by an imine reaction between periodate-oxidized GC and low-molecular-weight PEI. The molecular weight and composition were characterized using gel permeation chromatography column with multi-angle

H-L Jiang; J-T Kwon; Y-K Kim; E-M Kim; R Arote; H-J Jeong; J-W Nah; Y-J Choi; T Akaike; M-H Cho; C-S Cho

2007-01-01

29

Galactosylated chitosan- graft-poly(ethylene glycol) as hepatocyte-targeting DNA carrier  

Microsoft Academic Search

Lactobionic acid bearing galactose group was coupled with chitosan for liver specificity, and poly(ethylene glycol) (PEG) was grafted to galactosylated chitosan (GC) for stability in water and enhanced cell permeability. Complex formation of galactosylated chitosan-graft-PEG (GCP)\\/DNA complexes was confirmed by agarose gel electrophoresis. Compared to GC\\/DNA complex, the stability of GCP\\/DNA complex could be enhanced. Particle sizes of GCP\\/DNA complexes

I. K Park; T. H Kim; Y. H Park; B. A Shin; E. S Choi; E. H Chowdhury; T Akaike; C. S Cho

2001-01-01

30

Asialoglycoprotein-receptor-targeted hepatocyte imaging using 99mTc galactosylated chitosan.  

PubMed

This study investigated the usefulness of 99mTc hydrazinonicotinamide-galactosylated chitosan (HGC) in hepatocyte imaging. HGC was obtained by coupling the galactose moiety of both lactobionic acid and succinimidyl 6-hydrazinonicotinate hydrochloride (succinimidyl HYNIC). The coupled product was then radiolabeled with 99mTc using stannous chloride and tricine as reducing agent and coligand, respectively. Labeling efficiency was >90% both in room temperature and in serum up to 24 h after injection. The hepatic uptake properties of 99mTc HGC were studied in Balb/C mice. 99mTc HGC and 99mTc hydrazinonicotinamide chitosan (HC) were intravenously injected into mice, with receptor binding identified by coinjection with 9 and 14 mg of free galactose. Images were acquired with a gamma-camera. After injection via the tail vein of the mice, 99mTc HGC showed high selectivity for the liver, while 99mTc HC without a galactose group showed low liver uptake. In addition, the hepatic uptake of 99mTc HGC was blocked by coinjection of free galactose. Tissue distribution was determined at three different times (10, 60 and 120 min). The liver accumulated 13.16+/-2.72%, 16.11+/-5.70% and 16.55+/-2.28% of the injected dose per gram at 10, 60 and 120 min after injection, respectively. 99mTc HGC showed specific and rapid targeting of hepatocytes. It is a promising receptor-specific radiopharmaceutical with potential applications in liver imaging for the evaluation of hepatocytic function. PMID:16720245

Kim, Eun-Mi; Jeong, Hwan-Jeong; Kim, Se-Lim; Sohn, Myung-Hee; Nah, Jae-Woon; Bom, Hee-Seung; Park, In-Kyu; Cho, Chong-Su

2006-05-01

31

Depolymerized chitosans functionalized with bPEI as carriers of nucleic acids and tuftsin-tethered conjugate for macrophage targeting.  

PubMed

Development of efficient and safe nucleic acid carriers (vectors) is one of the essential requirements for the success of gene therapy. Here, we have evaluated the gene transfer capability of chitosan-PEI (CP) conjugates prepared by conjugating low molecular weight branched polyethylenimine (LMWP) with depolymerized chitosans (7 and 10 kDa) via their terminal aldehyde/keto groups. The CP conjugates interacted efficiently with nucleic acids and also showed higher cellular uptake. These conjugates on complexation with DNA yielded nanoparticles in the size range of 100-130 nm (in case of C7P) and 115-160 nm (in case of C10P), which exhibited significantly higher transfection efficiency (~2-42 folds) in vitro compared to chitosans (high and low mol. wt.) and the commercially available transfection reagents retaining cell viability almost comparable to the native chitosan. Of the two CP conjugates, chitosan 7 kDa-LMWP (C7P) displayed higher gene transfer ability in the presence and absence of serum. Luciferase reporter gene analysis in male Balb/c mice receiving intravenous administration of C7P3/DNA polyplex showed the maximum expression in their spleen. Further, tuftsin, a known macrophage targeting molecule, was tethered to C7P3 and the resulting complex, i.e., C7P3-T/DNA, exhibited significantly higher gene expression in cultured mouse peritoneal macrophages as compared to unmodified C7P3/DNA complex without any cytotoxicity demonstrating the suitability of the conjugate for targeted applications. Conclusively, the study demonstrates the potential of the projected conjugates for gene delivery for wider biomedical applications. PMID:22417621

Tripathi, Sushil K; Goyal, Ritu; Kashyap, Mahendra P; Pant, Aditya B; Haq, Wahajul; Kumar, Pradeep; Gupta, Kailash C

2012-06-01

32

In vitro cellular accumulation of gadolinium incorporated into chitosan nanoparticles designed for neutron-capture therapy of cancer  

Microsoft Academic Search

The accumulation of gadolinium loaded as gadopentetic acid (Gd-DTPA) in chitosan nanoparticles (Gd-nanoCPs), which were designed for gadolinium neutron-capture therapy (Gd-NCT) for cancer, was evaluated in vitro in cultured cells. Using L929 fibroblast cells, the Gd accumulation for 12 h at 37°C was investigated at Gd concentrations lower than 40 ppm. The accumulation leveled above 20 ppm and reached 18.0±2.7

Futoshi Shikata; Hiroyuki Tokumitsu; Hideki Ichikawa; Yoshinobu Fukumori

2002-01-01

33

Chitosan-plasmid DNA nanoparticles encoding small hairpin RNA targeting MMP-3 and -13 to inhibit the expression of dedifferentiation related genes in expanded chondrocytes.  

PubMed

Overexpression of matrix metalloproteinase (MMP)-3 and -13 can lead to the dedifferentiation of expanded chondrocytes. After implanting dedifferentiated cells for cartilage defect repair, graft failure may occur. Short hairpin RNA (shRNA) is a powerful genetic tool to reduce the expression of target genes. This study investigated the effects of chitosan-plasmid DNA (pDNA) nanoparticles encoding shRNA targeting MMP-3 and -13 on the dedifferentiation of expanded chondrocytes. The objective was to optimize the parameters of chitosan-pDNA formulation for achieving higher efficiency of pDNA delivery and gene silencing. The chitosan-pDNA nanoparticles were prepared using a complex coacervation process. Then the characteristics including size, shape, stability, and transfection efficiency were compared in different groups. The results indicated that chitosan of 800 kDa at N/P ratio of 4 and pH 7.0 was optimal to prepare chitosan-pDNA nanoparticles. These nanoparticles showed high DNA loading efficiency (95.8 ± 1.5%) and high gene transfection efficiency (24.5 ± 1.6%). After the expanded chondrocytes were transfected by chitosan-pDNA nanoparticles, MMP-3-610 and MMP-13-2024 groups showed greater suppression in mRNA and protein levels. The results indicated that chitosan-pDNA nanoparticles encoding shRNA targeting MMP-3 and -13 had great potential in silencing the dedifferentiation-related genes for regenerating prolonged and endurable cartilage. PMID:23520014

Zhao, Jingxin; Fan, Xiangli; Zhang, Qiang; Sun, Fangfei; Li, Xiaojian; Xiong, Chuan; Zhang, Chunli; Fan, Hongbin

2014-02-01

34

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

NASA Astrophysics Data System (ADS)

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 (-NH2, -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 T2-weighted negative contrast MR imaging agent were evaluated in folate-overexpressed HeLa and normal L929 fibroblast cells.

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

2011-04-01

35

Chitosan and its quaternized derivative as effective long dsRNA carriers targeting shrimp virus in Spodoptera frugiperda 9 cells.  

PubMed

RNA interference (RNAi) is a promising strategy to combat shrimp viral pathogens at lab-scale experiments. Development of effective orally delivered agents for double-stranded (ds)RNA is necessary for RNAi application at farm level. Since continuous shrimp cell lines have not been established, we are developing a dsRNA-delivery system in Spodoptera frugiperda (Sf9) cells for studying in vitro RNAi-mediated gene silencing of shrimp virus. Sf9 cells challenged with yellow head virus (YHV) were used for validating nanoparticles as effective dsRNA carriers. Inexpensive and biodegradable polymers, chitosan and its quarternized derivative (QCH4), were formulated with long dsRNA (>100 bp) targeting YHV. Their morphology and physicochemical properties were examined. When treated with chitosan- and QCH4-dsRNA complexes, at least 50% reduction in YHV infection in Sf9 cells relative to the untreated control was evident at 24h post infection with low cytoxicity. Inhibitory effects of chitosan- and QCH4-dsRNA complexes were comparable to that of dsRNA formulated with Cellfectin(®), a commercial lipid-based transfection reagent. The natural and quaternized chitosan prepared in this study can be used for shrimp virus-specific dsRNA delivery in insect cultures, and have potential for future development of dsRNA carriers in shrimp feed. PMID:22575788

Theerawanitchpan, Gatesara; Saengkrit, Nattika; Sajomsang, Warayuth; Gonil, Pattarapond; Ruktanonchai, Uracha; Saesoo, Somsak; Flegel, Timothy W; Saksmerprome, Vanvimon

2012-08-31

36

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

37

Evaluation of cytotoxicity and mechanism of apoptosis of doxorubicin using folate-decorated chitosan nanoparticles for targeted delivery to retinoblastoma  

Microsoft Academic Search

Nanoparticles are the new entities that can greatly limit the various side effects of systemic chemotherapy, and that coupled\\u000a with a targeting moiety enables site-specific delivery of drugs. Folate receptors are overexpressed in retinoblastoma cells,\\u000a thus these can specifically uptake the drug-loaded nanoparticles, thereby increasing the cytotoxicity at the tumor site. In\\u000a our work, doxorubicin-loaded chitosan nanoparticles was prepared and

Suphiya Parveen; Sanjeeb K. Sahoo

2010-01-01

38

Galactosylated chitosan (GC)- graft -poly(vinyl pyrrolidone) (PVP) as hepatocyte-targeting DNA carrier: in vitro transfection  

Microsoft Academic Search

Galactosylated chitosan-graft-poly(vinyl pyrrolidone) (GCPVP) was synthesized and characterized for hepatocyte-targeting gene carrier. GCPVP itself as\\u000a well as GCPVP\\/DNA complex had negligible cytotoxicity regardless of the concentration of GCPVP and the charge ratio, but GCPVP\\/DNA\\u000a complex had slightly cytotoxic effect on HepG2 cells only in the case of the higher charge ratio and 20 mM of Ca2+ concentration used. Through the

In-Kyu Park; Hu-Lin Jiang; Seung-Eun Cook; Myung-Haing Cho; Su-ll Kim; Hwan-Jeong Jeong; Toshihiro Akaike; Chong-Su Cho

2004-01-01

39

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

40

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

PubMed

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

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

2012-08-20

41

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

PubMed Central

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

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

2013-01-01

42

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. PMID:21976974

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

2011-01-01

43

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

PubMed Central

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

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

2013-01-01

44

Efficient pH Dependent Drug Delivery to Target Cancer Cells by Gold Nanoparticles Capped with Carboxymethyl Chitosan  

PubMed Central

Doxorubicin (DOX) was immobilized on gold nanoparticles (AuNPs) capped with carboxymethyl chitosan (CMC) for effective delivery to cancer cells. The carboxylic group of carboxymethyl chitosan interacts with the amino group of the doxorubicin (DOX) forming stable, non-covalent interactions on the surface of AuNPs. The carboxylic group ionizes at acidic pH, thereby releasing the drug effectively at acidic pH suitable to target cancer cells. The DOX loaded gold nanoparticles were effectively absorbed by cervical cancer cells compared to free DOX and their uptake was further increased at acidic conditions induced by nigericin, an ionophore that causes intracellular acidification. These results suggest that DOX loaded AuNPs with pH-triggered drug releasing properties is a novel nanotheraputic approach to overcome drug resistance in cancer. PMID:24821542

Madhusudhan, Alle; Reddy, Gangapuram Bhagavanth; Venkatesham, Maragoni; Veerabhadram, Guttena; Kumar, Dudde Anil; Natarajan, Sumathi; Yang, Ming-Yeh; Hu, Anren; Singh, Surya S.

2014-01-01

45

Tumor targetability and antitumor effect of docetaxel-loaded hydrophobically modified glycol chitosan nanoparticles  

Microsoft Academic Search

Hydrophobically modified glycol chitosan (HGC) nanoparticles, a new nano-sized drug carrier, were prepared by introducing a hydrophobic molecule, cholanic acid, to water soluble glycol chitosan. The HGC nanoparticles were easily loaded with the anticancer drug docetaxel (DTX) using a dialysis method, and the resulting docetaxel-loaded HGC (DTX-HGC) nanoparticles formed spontaneously self-assembled aggregates with a mean diameter of 350 nm in

Ho-Young Hwang; In-San Kim; Ick Chan Kwon; Yong-Hee Kim

2008-01-01

46

Norcantharidin-associated galactosylated chitosan nanoparticles for hepatocyte-targeted delivery  

Microsoft Academic Search

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

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

2010-01-01

47

Synthesis and characterization of chitosan-g-poly(ethylene glycol)-folate as a non-viral carrier for tumor-targeted gene delivery.  

PubMed

Poor water solubility and low transfection efficiency of chitosan are major drawbacks for its use as a gene delivery carrier. PEGylation can increase its solubility, and folate conjugation may improve gene transfection efficiency due to promoted uptake of folate receptor-bearing tumor cells. The aim of this study was to synthesize and characterize folate-poly(ethylene glycol)-grafted chitosan (FA-PEG-Chi) for targeted plasmid DNA delivery to tumor cells. Gel electrophoresis study showed strong DNA binding ability of modified chitosan. The pH(50) values, defined as the pH when the transmittance of a polymer solution at 600 nm has reached 50% of the original value, suggested that the water solubility of PEGylated chitosan had improved significantly. Regression analysis of pH(50) value as a function of substitution degree of PEG yielded an almost linear correlation for PEG-Chi and FA-PEG-Chi. The solubility of PEGylated chitosan decreased slightly by further conjugation of folic acid due to the relatively more hydrophobic nature of folic acid when compared to PEG. In addition, the chitosan-based DNA complexes did not induce remarkable cytotoxicity against HEK 293 cells. FA-PEG-Chi can be a promising gene carrier due to its solubility in physiological pH, efficiency in condensing DNA, low cytotoxicity and targeting ability. PMID:16999995

Chan, Peggy; Kurisawa, Motoichi; Chung, Joo Eun; Yang, Yi-Yan

2007-01-01

48

Preparation of estradiol chitosan nanoparticles for improving nasal absorption and brain targeting  

Microsoft Academic Search

The estradiol(E2)-loaded chitosan nanoparticles (CS-NPs) were prepared by ionic gelation of chitosan with tripolyphosphate anions (TPP). The CS-NPs had a mean size of (269.3±31.6)nm, a zeta potential of +25.4mV, and loading capacity of E2 CS-NPs suspension was 1.9mgml?1, entrapment efficiency was 64.7% on average. Subsequently, this paper investigated the levels of E2 in blood and the cerebrospinal fluid (CSF) in

Xiaomei Wang; Na Chi; Xing Tang

2008-01-01

49

Magnetic chitosan nanoparticles as a drug delivery system for targeting photodynamic therapy  

Microsoft Academic Search

Photodynamic therapy (PDT) has become an increasingly recognized alternative to cancer treatment in clinic. However, PDT therapy agents, namely photosensitizer (PS), are limited in application as a result of prolonged cutaneous photosensitivity, poor water solubility and inadequate selectivity, which are encountered by numerous chemical therapies. Magnetic chitosan nanoparticles provide excellent biocompatibility, biodegradability, non-toxicity and water solubility without compromising their magnetic

Yun Sun; Zhi-long Chen; Xiao-xia Yang; Peng Huang; Xin-ping Zhou; Xiao-xia Du

2009-01-01

50

Asialoglycoprotein-receptor-targeted hepatocyte imaging using 99mTc galactosylated chitosan  

Microsoft Academic Search

This study investigated the usefulness of 99mTc hydrazinonicotinamide-galactosylated chitosan (HGC) in hepatocyte imaging. HGC was obtained by coupling the galactose moiety of both lactobionic acid and succinimidyl 6-hydrazinonicotinate hydrochloride (succinimidyl HYNIC). The coupled product was then radiolabeled with 99mTc using stannous chloride and tricine as reducing agent and coligand, respectively. Labeling efficiency was >90% both in room temperature and in

Eun-Mi Kim; Hwan-Jeong Jeong; Se-Lim Kim; Myung-Hee Sohn; Jae-Woon Nah; Hee-Seung Bom; In-Kyu Park; Chong-Su Cho

2006-01-01

51

Galactosylated chitosan (GC)-graft-poly(vinyl pyrrolidone) (PVP) as hepatocyte-targeting DNA carrier  

Microsoft Academic Search

Galactosylated chitosan was conjugated with poly(vinyl pyrrolidone) (PVP) as a hydrophilic group. The complex formation of GC-graft-PVP (GCPVP)\\/DNA complexes was confirmed by agarose gel electrophoresis. The morphology of the complex observed by atomic force microscopy had a compact and spherical shape, around 40 nm particle sizes at a charge ratio of 3. The binding strength of GCPVP 10K\\/DNA complex measured

I. K. Park; J. E. Ihm; Y. H. Park; Y. J. Choi; S. I. Kim; W. J. Kim; T. Akaike; C. S. Cho

2003-01-01

52

Aptamer decorated hyaluronan/chitosan nanoparticles for targeted delivery of 5-fluorouracil to MUC1 overexpressing adenocarcinomas.  

PubMed

An aptamer (Apt) conjugated hyaluronan/chitosan nanoparticles (HACSNPs) were prepared as carrier for targeted delivery of 5-fluorouracil (5FU) to mucin1 (MUC1) overexpressing colorectal adenocarcinomas. Nanoparticles had about 181nm size, encapsulation efficiency of 45.5±2.8 and acceptable stability. Conjugation of MUC1-binding Apt to the surface of the nanoparticles was confirmed by gel electrophoresis. Toxicity and cellular uptake of nanoparticles were investigated by in vitro cytotoxicity assays and confocal scanning microscopy in (MUC1(+)) human adenocarcinoma and (MUC1(-)) Chinese hamster ovary cells. Toxicity of nanoparticles were significantly higher in comparison with free drug in both cell lines while this rising was more efficient for nanoparticles decorated with Apt in MUC1(+) cell line. The same result was observed in the cellular uptake study. It could be concluded that the present system has the potential to be considered in treatment of MUC1(+) colorectal adenocarcinomas. PMID:25659689

Ghasemi, Zahra; Dinarvand, Rassoul; Mottaghitalab, Fatemeh; Esfandyari-Manesh, Mehdi; Sayari, Elmira; Atyabi, Fatemeh

2015-05-01

53

Chitosan-graft-polyethylenimine/DNA nanoparticles as novel non-viral gene delivery vectors targeting osteoarthritis.  

PubMed

The development of safe and efficient gene carriers is the key to the clinical success of gene therapy. The present study was designed to develop and evaluate the chitosan-graft-polyethylenimine (CP)/DNA nanoparticles as novel non-viral gene vectors for gene therapy of osteoarthritis. The CP/DNA nanoparticles were produced through a complex coacervation of the cationic polymers with pEGFP after grafting chitosan (CS) with a low molecular weight (Mw) PEI (Mw?=?1.8 kDa). Particle size and zeta potential were related to the weight ratio of CP:DNA, where decreases in nanoparticle size and increases in surface charge were observed as CP content increased. The buffering capacity of CP was significantly greater than that of CS. The transfection efficiency of CP/DNA nanoparticles was similar with that of the Lipofectamine™ 2000, and significantly higher than that of CS/DNA and PEI (25 kDa)/DNA nanoparticles. The transfection efficiency of the CP/DNA nanoparticles was dependent on the weight ratio of CP:DNA (w/w). The average cell viability after the treatment with CP/DNA nanoparticles was over 90% in both chondrocytes and synoviocytes, which was much higher than that of PEI (25 kDa)/DNA nanoparticles. The CP copolymers efficiently carried the pDNA inside chondrocytes and synoviocytes, and the pDNA was detected entering into nucleus. These results suggest that CP/DNA nanoparticles with improved transfection efficiency and low cytotoxicity might be a safe and efficient non-viral vector for gene delivery to both chondrocytes and synoviocytes. PMID:24392152

Lu, Huading; Dai, Yuhu; Lv, Lulu; Zhao, Huiqing

2014-01-01

54

Nanoparticles of deoxycholic acid, polyethylene glycol and folic acid-modified chitosan for targeted delivery of doxorubicin.  

PubMed

Chitosan (CS) was first modified hydrophobically with deoxycholic acid (DCA) and then with polyethylene glycol (PEG) to obtain a novel amphiphilic polymer (CS-DCA-PEG). This was covalently bound to folic acid (FA) to develop nanoparticles (CS-DCA-PEG-FA) with tumor cell targeting property. The structure of the conjugates was characterised using Fourier transform infrared and (1)H nuclear magnetic resonance spectroscopy and X-ray diffraction. Based on self-aggregation, the conjugates formed nanoparticles with a low critical aggregation concentration of 0.035 mg/ml. The anti-cancer drug doxorubicin (DOX) was encapsulated into the nanoparticles with a drug-loading capacity of 30.2 wt%. The mean diameter of the DOX-loaded nanoparticles was about 200 nm, with a narrow size distribution. Transmission electron microscopy images showed that the DOX-loaded nanoparticles were spherical. The drug release was studied under different conditions. Furthermore, the cytotoxic activities of DOX in CS-DCA-PEG-FA nanoparticles against folate receptor (FR)-positive HeLa cells and FR-negative fibroblast 3T3 cells were evaluated. These results suggested that the CS-DCA-PEG-FA nanoparticles may be a promising vehicle for the targeting anticancer drug to tumor cells. PMID:24327111

Shi, Zhonggen; Guo, Rui; Li, Weichang; Zhang, Yi; Xue, Wei; Tang, Yu; Zhang, Yuanming

2014-03-01

55

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

PubMed

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

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

2012-07-01

56

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. PMID:23180965

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

2012-01-01

57

In vivo pharmacokinetics, biodistribution and anti-tumor effect of paclitaxel-loaded targeted chitosan-based polymeric micelle.  

PubMed

Abstract A water-insoluble anti-tumor agent, paclitaxel (PTX) was successfully incorporated into novel-targeted polymeric micelles based on tocopherol succinate-chitosan-polyethylene glycol-folic acid (PTX/TS-CS-PEG-FA). The aim of the present study was to evaluate the pharmacokinetics, tissue distribution and efficacy of PTX/TS-CS-PEG-FA in comparison to Anzatax® in tumor bearing mice. The micellar formulation showed higher in vitro cytotoxicity against mice breast cancer cell line, 4T1, due to the folate receptor-mediated endocytosis. The IC50 value of PTX, a concentration at which 50% cells are killed, was 1.17 and 0.93?µM for Anzatax® and PTX/TS-CS-PEG-FA micelles, respectively. The in vivo anti-tumor efficacy of PTX/TS-CS-PEG-FA, as measured by reduction in tumor volume of 4T1 mouse breast cancer injected in Balb/c mice was significantly greater than that of Anzatax®. Pharmacokinetic study in tumor bearing mice revealed that the micellar formulation prolonged the systemic circulation time of PTX and the AUC of PTX/TS-CS-PEG-FA was obtained 0.83-fold lower than Anzatax®. Compared with Anzatax®, the Vd, T1/2ß and MRT of PTX/TS-CS-PEG-FA was increased by 2.76, 2.05 and 1.68-fold, respectively. As demonstrated by tissue distribution, the PTX/TS-CS-PEG-FA micelles increased accumulation of PTX in tumor, therefore, resulted in anti-tumor effects enhancement and drug concentration in the normal tissues reduction. Taken together, our evaluations show that PTX/TS-CS-PEG-FA micelle is a potential drug delivery system of PTX for the effective treatment of the tumor and systematic toxicity reduction, thus, the micellar formulation can provide a useful alternative dosage form for intravenous administration of PTX. PMID:25188785

Rezazadeh, Mahboubeh; Emami, Jaber; Hasanzadeh, Farshid; Sadeghi, Hojjat; Minaiyan, Mohsen; Mostafavi, Abolfazl; Rostami, Mahboubeh; Lavasanifar, Afsaneh

2014-09-01

58

Chitosan/siRNA Nanoparticles Targeting Cyclooxygenase Type 2 Attenuate Unilateral Ureteral Obstruction-induced Kidney Injury in Mice  

PubMed Central

Cyclooxygenase type 2 (COX-2) plays a predominant role in the progression of kidney injury in obstructive nephropathy. The aim of this study was to test the efficacy of chitosan/small interfering RNA (siRNA) nanoparticles to knockdown COX-2 specifically in macrophages to prevent kidney injury induced by unilateral ureteral obstruction (UUO). Using optical imaging techniques and confocal microscopy, we demonstrated that chitosan/siRNA nanoparticles accumulated in macrophages in the obstructed kidney. Consistent with the imaging data, the obstructed kidney contained a higher amount of siRNA and macrophages. Chitosan-formulated siRNA against COX-2 was evaluated on RAW macrophages demonstrating reduced COX-2 expression and activity after LPS stimulation. Injection of COX-2 chitosan/siRNA nanoparticles in mice subjected to three-day UUO diminished the UUO-induced COX-2 expression. Likewise, macrophages in the obstructed kidney had reduced COX-2 immunoreactivity, and histological examination showed lesser tubular damage in COX-2 siRNA-treated UUO mice. Parenchymal inflammation, assessed by tumor necrosis factor-alpha (TNF-?) and interleukin 6 mRNA expression, was attenuated by COX-2 siRNA. Furthermore, treatment with COX-2 siRNA reduced heme oxygenase-1 and cleaved caspase-3 in UUO mice, indicating lesser oxidative stress and apoptosis. Our results demonstrate a novel strategy to prevent UUO-induced kidney damage by using chitosan/siRNA nanoparticles to knockdown COX-2 specifically in macrophages. PMID:25553102

Yang, Chuanxu; Nilsson, Line; Cheema, Muhammad Umar; Wang, Yan; Frøkiær, Jørgen; Gao, Shan; Kjems, Jørgen; Nørregaard, Rikke

2015-01-01

59

Radiation synthesis and magnetic properties of novel Co 0.7Fe 0.3/Chitosan compound nanoparticles for targeted drug carrier  

NASA Astrophysics Data System (ADS)

Chitosan coated Co 0.7Fe 0.3 compound nanoparticles were successfully synthesized through a ?-radiation route in inverse microemulsion system. An observation of transmission electron microscope (TEM) showed that the diameter of these nanoparticles was about 50 nm with narrow size-distribution. Investigations of properties of nanoparticles were also conducted with fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD) and energy dispersion spectrum (EDS). Analysis of vibrating sample magnetometer (VSM) indicated that the nanoparticles were superparamagnetic with a saturation magnetization of 24 emu/g. These compound nanoparticles were undertaken to allow for the magnetically targeted cancer.

Kang, Bin; Chang, Shu-quan; Dai, Yao-dong; Chen, Da

2007-06-01

60

Characterization of chitosan magnetic nanoparticles for in situ delivery of tissue plasminogen activator  

Microsoft Academic Search

In this study, we examine the preparation of chitosan-coated magnetic nanoparticle (MNP) (chitosan-MNP) and the feasibility of using tissue plasminogen activator (tPA) covalently bound to chitosan-MNP surface (chitosan-MNP–tPA) for magnetic targeted delivery of the thrombolytic drug. The physicochemical properties of chitosan-MNP prepared with increasing chitosan\\/MNP ratios were characterized in detail. The optimum drug loading is reached when 0.5mg tPA is

Jyh-Ping Chen; Pei-Chin Yang; Yunn-Hwa Ma; Tony Wu

2011-01-01

61

Cancer-targeted MDR-1 siRNA delivery using self-cross-linked glycol chitosan nanoparticles to overcome drug resistance.  

PubMed

P-glycoprotein (Pgp) mediated multi-drug resistance (MDR) is a major cause of failure in chemotherapy. In this study, small interfering RNA (siRNA) for Pgp down-regulation was delivered to tumors to overcome MDR in cancer. To achieve an efficient siRNA delivery in vivo, self-polymerized 5'-end thiol-modified siRNA (poly-siRNA) was incorporated in tumor targeting glycol chitosan nanoparticles. Pgp-targeted poly-siRNA (psi-Pgp) and thiolated glycol chitosan polymers (tGC) formed stable nanoparticles (psi-Pgp-tGC NPs), and the resulting nanoparticles protected siRNA molecules from enzymatic degradation. The psi-Pgp-tGC NPs could release functional siRNA molecules after cellular delivery, and they were able to facilitate siRNA delivery to Adriamycin-resistant breast cancer cells (MCF-7/ADR). After intravenous administration, the psi-Pgp-tGC NPs accumulated in MCF-7/ADR tumors and down-regulated P-gp expression to sensitize cancer cells. Consequently, chemo-siRNA combination therapy significantly inhibited tumor growth without systemic toxicity. These psi-Pgp-tGC NPs showed great potential as a supplementary therapeutic agent for drug-resistant cancer. PMID:25481438

Yhee, Ji Young; Song, Seungyong; Lee, So Jin; Park, Sung-Gurl; Kim, Ki-Suk; Kim, Myung Goo; Son, Sejin; Koo, Heebeom; Kwon, Ick Chan; Jeong, Ji Hoon; Jeong, Seo Young; Kim, Sun Hwa; Kim, Kwangmeyung

2015-01-28

62

A chitosan-graft-PEI-candesartan conjugate for targeted co-delivery of drug and gene in anti-angiogenesis cancer therapy.  

PubMed

A multifunctional copolymer-anticancer conjugate chitosan-graft-polyethyleneimine-candesartan (CPC) containing low molecular weight chitosan (CS) backbone and polyethyleneimine (PEI) arms with candesartan (CD) conjugated via an amide bond was fabricated as a targeted co-delivery nanovector of drug and gene for potential cancer therapy. Here, CD was utilized to specifically bind to overexpressed angiotensin II type 1 receptor (AT1R) of tumor cells, strengthen endosomal buffering capacity of CPC and suppress tumor angiogenesis. The self-assembled CPC/pDNA complexes exhibited desirable and homogenous particle size, moderate positive charges, superior stability, and efficient release of drug and gene in vitro. Flow cytometry and confocal laser scanning microscopy analyses confirmed that CD-targeted function and CD-enhanced buffering capacity induced high transfection, specific cellular uptake and efficient intracellular delivery of CPC/pDNA complexes in AT1R-overexpressed PANC-1 cells. In addition, CPC/wt-p53 complexes co-delivering CD and wild type p53 (wt-p53) gene achieved synergistic angiogenesis suppression by more effectively downregulating the expression of vascular endothelial growth factor (VEGF) mRNA and protein via different pathways in vitro, as compared to mono-delivery and mixed-delivery systems. In vivo investigation on nude mice bearing PANC-1 tumor xenografts revealed that CPC/wt-p53 complexes possessed high tumor-targeting capacity and strong anti-tumor activity. Additional analysis of microvessel density (MVD) demonstrated that CPC/wt-p53 complexes significantly inhibited tumor-associated angiogenesis. These findings suggested that CPC could be an ideal tumor-targeting nanovector for simultaneous transfer of drug and gene, and a multifunctional CPC/wt-p53 co-delivery system with tumor-specific targetability, enhanced endosomal buffering capacity and synergistic anti-angiogenesis efficacy might be a new promising strategy for effective tumor therapy. PMID:24997481

Bao, Xiuli; Wang, Wei; Wang, Cheng; Wang, Yu; Zhou, Jianping; Ding, Yang; Wang, Xiaoyi; Jin, Yuting

2014-09-01

63

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

2013-01-01

64

Carboxymethyl chitosan-folic acid-conjugated Fe3O4@SiO2 as a safe and targeting antitumor nanovehicle in vitro  

PubMed Central

A synthetic method to prepare a core-shell-structured Fe3O4@SiO2 as a safe nanovehicle for tumor cell targeting has been developed. Superparamagnetic iron oxide is encapsulated inside nonporous silica as the core to provide magnetic targeting. Carboxymethyl chitosan-folic acid (OCMCS-FA) synthesized through coupling folic acid (FA) with OCMCS is then covalently linked to the silica shell and renders new and improved functions because of the original biocompatible properties of OCMCS and the targeting efficacy of FA. Cellular uptake of the nanovehicle was assayed by confocal laser scanning microscope using rhodamine B (RB) as a fluorescent marker in HeLa cells. The results show that the surface modification of the core-shell silica nanovehicle with OCMCS-FA enhances the internalization of nanovehicle to HeLa cells which over-express the folate receptor. The cell viability assay demonstrated that Fe3O4@SiO2-OCMCS-FA nanovehicle has low toxicity and can be used as an eligible candidate for drug delivery system. These unique advantages make the prepared core-shell nanovehicle promising for cancer-specific targeting and therapy. PMID:24667013

2014-01-01

65

Synthesis and formulation of methotrexate (MTX) conjugated LaF3:Tb(3+)/chitosan nanoparticles for targeted drug delivery applications.  

PubMed

Chitosan functionalized luminescent rare earth doped terbium nanoparticles (LaF3:Tb(3+)/chi NPs) as a drug carrier for methotrexate (MTX) was designed using a simple chemical precipitation method. The synthesized chitosan functionalized nanoparticles were found to be spherical in shape with an average diameter of 10-12nm. They are water soluble and biocompatible, in which the hydroxyl and amino functional groups on its surface are utilized for the bioconjugation of the anticancer drug, the methotrexate. The nature of MTX binding with LaF3:Tb(3+)/chi nanoparticles were examined using X-ray diffraction, zeta potential analyzer and transmission electron microscopy. The other interactions due to complex formation between MTX and LaF3:Tb(3+)/chi NPs were carried out by UV-Visible, steady and excited state fluorescence spectroscopy. The photo-physical characterization revealed that the adsorption and release of MTX from LaF3:Tb(3+)/chi NPs is faster than gold nanoparticles and also confirms that this may be due to weak interaction i.e. the Vander Waals force of attraction between the carboxyl and amino group of drug and nanoparticles. The maximum percentage yield and entrapment efficiency of 85.91±0.71 and 83.82± 0.14 were achieved at a stochiometric ratio of 4:5 of MTX and LaF3:Tb(3+)/chi nanoparticles respectively. In addition, antitumoral activity study reveals that MTX conjugated LaF3:Tb(3+)/chi nanoparticles show higher cytotoxic effect on MCF-7 breast cancer cell lines than that of free MTX. PMID:25661354

Mangaiyarkarasi, Rajendiran; Chinnathambi, Shanmugavel; Aruna, Prakasarao; Ganesan, Singaravelu

2015-02-01

66

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. PMID:23986877

Ofokansi, Kenneth Chibuzor; Kenechukwu, Franklin Chimaobi

2013-01-01

67

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

PubMed Central

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

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

2014-01-01

68

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. PMID:22267927

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

2011-01-01

69

Redox targeting of DNA anchored to MWCNTs and TiO2 nanoparticles dispersed in poly dialyldimethylammonium chloride and chitosan.  

PubMed

A key issue associated with electrochemical DNA-based biosensors is how to enhance DNA immobilization on the substrates. In order to improve the immobilization of DNA and to optimize DNA interaction efficiency, different kinds of strategies have been developed. In this regard, nanomaterials have attracted a great deal of attention in electrode surface modification for DNA biosensor fabrication. In this study, nanostructured films were deposited at the surface of a pencil graphite electrode (PGE) as a working electrode. For the present purpose, common polyelectrolytes are used for surface modification with double-stranded DNA. Two positively charged polyelectrolyte, namely poly dialyldimethylammonium chloride (PDDA) and chitosan, are initially compared for DNA immobilization at the surface of MWCNTs and TiO2 nanoparticles (TiO2NPs). In a second step, the basic electrochemical properties of the sensors are investigated using voltammetric methods. The modified electrodes are also characterized by scanning electron microscopy and electrochemical impedance measurements. It will be shown that electrode modification with DNA and the nanostructure that disperses in PDDA leads to an enhanced sensitivity of the DNA voltammetric detection mechanism. In a previous study, a comparison was done between MWCNTs and TiO2NPs for determining the effect of nanoparticle effect on DNA immobilization on the electrode surface. In order to compare the efficiency of the prepared DNA-based biosensors, methylene blue is chosen as an electroactive probe. It will be shown that the stability of the immobilized DNA within several days will be much higher when MWCNTs rather than TiO2NPs are used. PMID:24952239

Ensafi, Ali A; Nasr-Esfahani, Parisa; Heydari-Bafrooei, Esmaeil; Rezaei, B

2014-09-01

70

Multifunctional Chitosan Magnetic-Graphene (CMG) Nanoparticles: a Theranostic Platform for Tumor-targeted Co-delivery of Drugs, Genes and MRI Contrast Agents.  

PubMed

Combing chemotherapy with gene therapy has been one of the most promising strategies for the treatment of cancer. The noninvasive MRI with superparamagnetic iron oxide (SPIO) as contrast agent is one of the most effecitve techniques for evaluating the antitumor therapy. However, to construct a single system that can deliver efficiently gene, drug and SPIO to the cancer site remains a challenge. Herein, we report a chitosan functionalized magnetic graphene nanoparticle (CMG) platform for simultaneous gene/drug and SPIO delivery to tumor. The phantom and ex vivo MRI images suggest CMG as a strong T2 contrast-enhancing agent. The CMGs are biocompatible as evaluated by the WST assay and predominantly accumulate in tumors as shown by biodistribution studies and MRI. The anticancer drug doxorubicin (DOX) loaded CMGs (DOX-CMGs) release DOX faster at pH 5.1 than at pH 7.4, and more effective (IC50 = 2 ?M) in killing A549 lung cancer cells than free DOX (IC50 = 4 ?M). CMGs efficiently deliver DNA into A549 lung cancer cells and C42b prostate cancer cells. In addition, i.v. administration of GFP-plasmid encapsulated within DOX-CMGs into tumor-bearing mice has showed both GFP expression and DOX accumulation at the tumor site at 24 and 48 hrs after administration. These results indicate CMGs provide a robust and safe theranostic platform, which integrates targeted delivery of both gene medicine and chemotherapeutic drug(s), and enhanced MR imaging of tumors. The integrated chemo- and gene- therapeutic and diagnostic design of CMG nanoparticles shows promise for simultaneous targeted imaging, drug delivery and real -time monitoring of therapeutic effect for cancer. PMID:24883188

Wang, Chunyan; Ravi, Sowndharya; Garapati, Ujjwala Sree; Das, Mahasweta; Howell, Mark; MallelaMallela, Jaya; Alwarapan, Subbiah; Mohapatra, Shyam S; Mohapatra, Subhra

2013-09-21

71

Multifunctional Chitosan Magnetic-Graphene (CMG) Nanoparticles: a Theranostic Platform for Tumor-targeted Co-delivery of Drugs, Genes and MRI Contrast Agents  

PubMed Central

Combing chemotherapy with gene therapy has been one of the most promising strategies for the treatment of cancer. The noninvasive MRI with superparamagnetic iron oxide (SPIO) as contrast agent is one of the most effecitve techniques for evaluating the antitumor therapy. However, to construct a single system that can deliver efficiently gene, drug and SPIO to the cancer site remains a challenge. Herein, we report a chitosan functionalized magnetic graphene nanoparticle (CMG) platform for simultaneous gene/drug and SPIO delivery to tumor. The phantom and ex vivo MRI images suggest CMG as a strong T2 contrast-enhancing agent. The CMGs are biocompatible as evaluated by the WST assay and predominantly accumulate in tumors as shown by biodistribution studies and MRI. The anticancer drug doxorubicin (DOX) loaded CMGs (DOX-CMGs) release DOX faster at pH 5.1 than at pH 7.4, and more effective (IC50 = 2 ?M) in killing A549 lung cancer cells than free DOX (IC50 = 4 ?M). CMGs efficiently deliver DNA into A549 lung cancer cells and C42b prostate cancer cells. In addition, i.v. administration of GFP-plasmid encapsulated within DOX-CMGs into tumor-bearing mice has showed both GFP expression and DOX accumulation at the tumor site at 24 and 48 hrs after administration. These results indicate CMGs provide a robust and safe theranostic platform, which integrates targeted delivery of both gene medicine and chemotherapeutic drug(s), and enhanced MR imaging of tumors. The integrated chemo- and gene- therapeutic and diagnostic design of CMG nanoparticles shows promise for simultaneous targeted imaging, drug delivery and real -time monitoring of therapeutic effect for cancer. PMID:24883188

Wang, Chunyan; Ravi, Sowndharya; Garapati, Ujjwala Sree; Das, Mahasweta; Howell, Mark; MallelaMallela, Jaya; Alwarapan, Subbiah; Mohapatra, Shyam S.; Mohapatra, Subhra

2014-01-01

72

Real-time and non-invasive optical imaging of tumor-targeting glycol chitosan nanoparticles in various tumor models  

Microsoft Academic Search

Recently, various nanoparticle systems have been developed for tumor-targeted delivery of imaging agents or drugs. However, large amount of them still have insufficient tumor accumulation and this limits their further clinical applications. Moreover, the in vivo characteristics of nanoparticles have been largely unknown, because there are few proper technologies to achieve the direct and non-invasive characterization of nanoparticles in live

Jin Hee Na; Heebeom Koo; Sangmin Lee; Kyung Hyun Min; Heon Yoo; Seung Hoon Lee; Jae Hyung Park; Ick Chan Kwon; Seo Young Jeong; Kwangmeyung Kim

2011-01-01

73

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

2013-11-18

74

Pegylation effect of chitosan based polyplex on DNA transfection.  

PubMed

The aim of this study was to develop hepatocyte-targeting non-viral polymeric nono-carriers for gene delivery. Chitosan was selected as the main polymer. An asialoglycoprotein receptor recognized sugar, galactose, was introduced. The methoxy poly(ethylene glycol) (mPEG) or short chain poly(ethylene glycol) diacid (PEGd) was further grafted onto galactosylated chitosan. All polyplex possessed positive charge character. The compaction of DNA by grafted chitosan was in order of chitosan-galactose-mPEG>chitosan-galactose-PEGd>chitosan-galactose where the chitosan-galactose-mPEG and pDNA formed the most stable polyplex. The polyplex prominently enhanced DNA cellular transfection as compared to naked DNA in HepG2 cells in order of chitosan-galactose/pDNA (11.6±0.6-33.0±4.4%)>chitosan-galactose-PEGd/pDNA (12.7±2.5-15.5±3.0%)>chitosan-galactose-mPEG/pDNA (9.0±1.1-12.9±2.4%). PMID:25662681

Lin, Wen Jen; Hsu, Wan Yi

2015-04-20

75

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

PubMed Central

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

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

2013-01-01

76

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

77

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

78

Chitosan Microspheres in Novel Drug Delivery Systems  

PubMed Central

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

Mitra, Analava; Dey, Baishakhi

2011-01-01

79

Radiation synthesis and magnetic properties of novel Co 0.7Fe 0.3\\/Chitosan compound nanoparticles for targeted drug carrier  

Microsoft Academic Search

Chitosan coated Co0.7Fe0.3 compound nanoparticles were successfully synthesized through a ?-radiation route in inverse microemulsion system. An observation of transmission electron microscope (TEM) showed that the diameter of these nanoparticles was about 50nm with narrow size-distribution. Investigations of properties of nanoparticles were also conducted with fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD) and energy dispersion spectrum (EDS). Analysis of

Bin Kang; Shu-Quan Chang; Yao-Dong Dai; Da Chen

2007-01-01

80

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. PMID:23829873

2013-01-01

81

Enzyme-sensing chitosan hydrogels.  

PubMed

We report on a chitosan hydrogel-based platform for the detection of enzymes, which is compatible with the implementation in infection-sensing wound dressings. Thin films of the established wound dressing biopolymer chitosan were functionalized with a fluorogenic substrate, which is released upon enzymatic degradation, resulting in a pronounced increase in fluorescence emission intensity. In this first model study, the fluorogenic substrate alanyl-alanyl-phenylalanine-7-amido-4-methylcoumarin (AAP-AMC) was covalently conjugated via amide bond formation to chitosan and was shown to facilitate the detection of the serine protease ?-chymotrypsin. Systematic investigations established the dependence of hydrogel thickness and substrate loading on the hydrogel preparation conditions, as well as the dependence of the rate of the reaction on the initial enzyme concentration and the loading of AAP-AMC in the hydrogel. The initial release rate of the fluorophore 7-AMC was found to be linear with enzyme concentration and substrate loading and was independent of hydrogel thickness. Under optimized conditions the hydrogel reports the presence of ?-chymotrypsin in <5 min with a limit of detection of ?10 nM. This generic approach, which can be adapted to detect different kinds of enzymes by using appropriate fluorogenic or chromogenic substrates, is highly interesting for targeting the detection of specific pathogenic bacteria, e.g., in wound dressings. PMID:24914451

Sadat Ebrahimi, Mir Morteza; Schönherr, Holger

2014-07-01

82

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

83

Comparative study of photosensitizer loaded and conjugated glycol chitosan nanoparticles for cancer therapy  

Microsoft Academic Search

This study reports that tumor-targeting glycol chitosan nanoparticles with physically loaded and chemically conjugated photosensitizers can be used in photodynamic therapy (PDT). First, the hydrophobic photosensitizer, chlorin e6 (Ce6), was physically loaded onto the hydrophobically-modified glycol chitosan nanoparticles (HGC), which were prepared by self-assembling amphiphilic glycol chitosan-5?-cholanic acid conjugates under aqueous conditions. Second, the Ce6s were chemically conjugated to the

So Jin Lee; Heebeom Koo; Hayoung Jeong; Myung Sook Huh; Yongseok Choi; Seo Young Jeong; Youngro Byun; Kuiwon Choi; Kwangmeyung Kim; Ick Chan Kwon

2011-01-01

84

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

PubMed

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

Jarmila, Vinsová; Vavríková, Eva

2011-01-01

85

Folate receptor targeted self-assembled chitosan-based nanoparticles for SPECT/CT imaging: demonstrating a preclinical proof of concept.  

PubMed

A new biocompatible, biodegradable, self-assembled chitosan-based nanoparticulate product was successfully synthesized and radiolabeled with technetium-99m, and studied as a potential new SPECT or SPECT/CT imaging agent for diagnosis of folate receptor overexpressing tumors. In the present study we examined the conditions of a preclinical application of this labeled nanosystem in early diagnosis of spontaneously diseased veterinary patient using a human SPECT/CT device. The results confirmed that the nanoparticles accumulated in tumor cells overexpressing folate receptors, contrast agent revealed higher uptake in the tumor for a long time. Preclinical trials verified that the new nanoparticles are able to detect folate-receptor-overexpressing tumors in spontaneously diseased animal models with enhanced contrast. PMID:25093694

Polyák, András; Hajdu, István; Bodnár, Magdolna; Dabasi, Gabriella; Jóba, Róbert P; Borbély, János; Balogh, Lajos

2014-10-20

86

Surface grafted chitosan gels. Part I. Molecular insight into the formation of chitosan and poly(acrylic acid) multilayers.  

PubMed

Composite polyelectrolyte multilayers of chitosan and low molecular weight poly(acrylic acid) (PAA) have been assembled by sequential adsorption as a first step toward building a surface anchored chitosan gel. Silane chemistry was used to graft the first chitosan layer to prevent film detachment and decomposition. The assembly process is characterized by nonlinear growth behavior, with different adsorption kinetics for chitosan and PAA. In situ analysis of the multilayer by means of surface sensitive total internal reflection Raman (TIRR) spectroscopy, combined with target factor analysis of the spectra, provided information regarding composition, including water content, and ionization state of weak acidic and basic groups present in the thin composite film. Low molecular weight PAA, mainly in its protonated form, diffuses into and out of the composite film during adsorption and rinsing steps. The higher molecular weight chitosan shows a similar behavior, although to a much lower extent. Our data demonstrate that the charged monomeric units of chitosan are mainly compensated by carboxylate ions from PAA. Furthermore, the morphology and mechanical properties of the multilayers were investigated in situ using atomic force microscopy operating in PeakForce tapping mode. The multilayer consists of islands that grow in lateral dimension and height during the build-up process, leading to close to exponentially increasing roughness with deposition number. Both diffusion in and out of at least one of the two components (PAA) and the island-like morphology contribute to the nonlinear growth of chitosan/PAA multilayers. PMID:25007398

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

2014-07-29

87

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

PubMed Central

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

Mohd Sultan, Norfazila

2014-01-01

88

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

PubMed

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

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

2013-06-15

89

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

PubMed

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

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

2013-12-01

90

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

2012-09-01

91

Chitosan (polysaccharide) Cationic polyelectrolyte (NH3  

E-print Network

Chitosan (polysaccharide) Cationic polyelectrolyte (NH3 +) pH dependant solubility (pH to hydrogen evolution Chitosan molecules deprotonate and immobilized at electrode surface Electrochemical reaction rate depends on current density Electrochemical deposition of chitosan Thin film formation

Rubloff, Gary W.

92

Effects of molecular weights on the absorption, distribution and urinary excretion of intraperitoneally administrated carboxymethyl chitosan in rats.  

PubMed

Carboxymethyl chitosan (CM-chitosan) is one of water-soluble derivatives of chitosan. Numerous studies have been focused on its applications as pharmaceutical excipient, bioactive reagent and nontoxic drug carrier. Like other polysaccharides, CM-chitosan is inhomogenous in molecular weight. Originations and preparation procedures considerably influence its molecular weight and molecular weight distributions. Understanding the molecular weight related biological behaviour of this inhomogenous glycopolymer in vivo were crucial for the quality control and clinical applications of chitosan and chitosan based medical devices. In this study, we investigated the effects of molecular weights on the absorption, distribution, degradation and urinary excretion of the fluorescein isothiocyanate-labeled CM-chitosan in rats. The results indicated that molecular weight significantly influenced the uptake of CM-chitosan from the lumen of abdomen and blood vessels to peripheral tissues, the distribution of this chemical and urinary excretion after intraperitoneal administration. These findings provided an important reference for the clinical applications of this versatile derivative of chitosan as postsurgical and other biomedical materials and important clues for the exploitation of CM-chitosan based drug targeting and delivery systems. PMID:22890521

Dong, Wen; Han, Baoqin; Shao, Kai; Yang, Zhao; Peng, Yanfei; Yang, Yan; Liu, Wanshun

2012-12-01

93

Antibacterial activity of chemically defined chitosans: influence of molecular weight, degree of acetylation and test organism.  

PubMed

Chitosans, polysaccharides obtained from the exoskeleton of crustaceans, have been shown to exert antibacterial activity in vitro and their use as a food preservative is of growing interest. However, beyond a consensus that chitosan appears to disrupt the bacterial cell membrane, published data are inconsistent on the chemical characteristics that confer the antibacterial activity of chitosan. While most authors agree that the net charge density of the polymer (reflected in the fraction of positively charged amino groups at the C-2 position of the glucosamine unit) is an important factor in antibacterial activity, conflicting data have been reported on the effect of molecular weight and on the susceptibility among different bacterial species to chitosan. Therefore, we prepared batches of water-soluble hydrochloride salts of chitosans with weight average molecular weights (M(w)) of 2-224kDa and degree of acetylation of 0.16 and 0.48. Their antibacterial activity was evaluated using tube inhibition assays and membrane integrity assays (N-Phenyl-1-naphthylamine fluorescence and potassium release) against Bacillus cereus, Escherichia coli, Salmonella Typhimurium and three lipopolysaccharide mutants of E. coli and S. Typhimurium. Chitosans with lower degree of acetylation (F(A)=0.16) were more active than the more acetylated chitosans (F(A)=0.48). No trends in antibacterial action related to increasing or decreasing M(w) were observed although one of the chitosans (M(w) 28.4kDa, F(A)=0.16) was more active than the other chitosans, inhibiting growth and permeabilizing the membrane of all the test strains included. The test strains varied in their susceptibility to the different chitosans with wild type S. Typhimurium more resistant than the wild type E. coli. Salmonellae lipopolysaccharide mutants were more susceptible than the matched wild type strain. Our results show that the chitosan preparation details are critically important in identifying the antibacterial features that target different test organisms. PMID:21605923

Mellegård, H; Strand, S P; Christensen, B E; Granum, P E; Hardy, S P

2011-07-15

94

CHITOSAN DERIVATIVES FOR TISSUE ENGINEERING.  

E-print Network

??Chitosan, a naturally occurring polysaccharide, and its derivatives have been widely explored for biomedical applications due to their biocompatibility and biodegradability. In our studies, we… (more)

Qiu, Yongzhi

2008-01-01

95

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

96

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

97

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

98

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

Microsoft Academic Search

To make a tumor targeting nano-sized drug delivery system, biocompatible and biodegradable glycol chitosan (Mw=250 kDa) was modified with hydrophobic cholanic acid. The resulting hydrophobically modified glycol chitosans (HGCs) that formed nano-sized self-aggregates in an aqueous medium were investigated as an anticancer drug carrier in cancer treatment. Insoluble anticancer drug, cisplatin (CDDP), was easily encapsulated into the hydrophobic cores of HGC

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

2008-01-01

99

In vitro characterization, and in vivo studies of crosslinked lactosaminated carboxymethyl chitosan nanoparticles  

Microsoft Academic Search

The liver targeting and controlled release nanoparticles based on carboxymethyl chitosan derivatives were prepared: firstly, novel thiolated lactosaminated carboxymethyl chitosan (LAC-CMC) was synthesized, its chemical structure was characterized by 1H NMR spectroscopy. Then, glycyrrhizic acid was chosen as model drug and encapsulated within thiolated LAC-CMC nanoparticles through ionic gelification. The crosslinked glycyrrhizic acid-loaded nanoparticles dissociated to release drug in the

Hua Zheng; Xueqiong Zhang; Yihua Yin; Fuliang Xiong; Xiaoyu Gong; Zhongjia Zhu; Bo Lu; Peihu Xu

2011-01-01

100

siRNA delivery with chitosan nanoparticles: Molecular properties favoring efficient gene silencing.  

PubMed

Chitosan has gained increasing interest for siRNA delivery. Although chitosan covers a family of structurally different polysaccharides, most siRNA delivery studies have been performed with conventional partially N-acetylated chitosans. Herein, the purpose was to identify fundamental chitosan molecular properties favoring siRNA delivery and efficient gene silencing in mammalian cells. Nanoparticles were prepared from well-defined chitosans of various chemical compositions, degrees of polymerization (DP(n)) and chain architectures. Structure-activity relationships were determined by the cellular uptake of siRNA and the knockdown efficiency at mRNA and protein levels. Additionally, the nanoparticle cytotoxicity was evaluated on the basis of cellular metabolic activity and membrane integrity. Our results show that the most efficient gene silencing was achieved using fully de-N-acetylated chitosans with intermediate chain lengths (DP(n) 100-300). These chitosans mediated efficient siRNA delivery at low siRNA concentrations and, in several cell lines, potent long-term silencing of both exogenous and endogenous target genes, with minimal cytotoxicity. PMID:22119955

Malmo, Jostein; Sørgård, Hanne; Vårum, Kjell M; Strand, Sabina P

2012-03-10

101

Radiation-induced changes in carboxymethylated chitosan  

NASA Astrophysics Data System (ADS)

This study focuses on the radiation effect of ?-ray on carboxymethylated chitosan (CM-chitosan) in solid state. The changes in molecular weight of CM-chitosan with absorbed dose were monitored by viscosity method. Experimental results indicated that random chain scissions took place under irradiation. Radiation chemical yield ( Gd) of CM-chitosan in solid state with N 2-saturated was 0.49, which showed CM-chitosan has high radiation stability. Biomaterials composed of CM-chitosan can be thought to sterilize with low absorbed dose. FTIR and UV spectra showed that main chain structures of CM-chitosan were retained, carbonyl/carboxyl groups were formed and partial amino groups were eliminated in high absorbed dose. XRD patterns identified that the degradation of CM-chitosan occurred mostly in amorphous region.

Huang, Ling; Peng, Jing; Zhai, Maolin; Li, Jiuqiang; Wei, Genshuan

2007-11-01

102

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

PubMed

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

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

2014-11-27

103

Cytotoxic activities of chitosan nanoparticles and copper-loaded nanoparticles  

Microsoft Academic Search

Chitosan nanoparticles and copper(II)-loaded chitosan nanoparticles were prepared based on the ionic gelation of chitosan with tripolyphosphate anions and copper ion sorption. In this study, the cytotoxic activities of the chitosan nanoparticles and copper(II)-loaded chitosan nanoparticles was investigated and a relationship between physiochemical properties and activity is suggested. The chitosan nanoparticles and copper(II)-loaded chitosan nanoparticles elicited dose-dependent inhibitory effects on

Lifeng Qi; Zirong Xu; Xia Jiang; Yan Li; Minqi Wang

2005-01-01

104

Magnetic core-shell chitosan nanoparticles: rheological characterization and hyperthermia application.  

PubMed

Stabilized magnetic nanoparticles are the subject of intense research for targeting applications and this work deals with the design, preparation and application of specific core-shell nanoparticles based on ionic crosslinked chitosan. The nanometric size of the materials was demonstrated by dynamic light scattering (DLS) and field emission scanning electron microscopy (FESEM) that also proved an increase of the size of chitosan nanoparticles (NPs) with the magnetite content. Steady oscillatory rheology measurements revealed a gel-like behavior of aqueous dispersions of chitosan NPs with concentrations ranging from 0.5% to 2.0% (w/v). The cytotoxicity of all the materials synthesized was analyzed in human fibroblasts cultures using the Alamar Blue and lactate dehydrogenase (LDH) assays. The measured specific power absorption under alternating magnetic fields (f = 580 kHz, H = 24 kA/m) indicated that magnetic core-shell chitosan NPs can be useful as remotely driven heaters for magnetic hyperthermia. PMID:24507337

Zamora-Mora, Vanessa; Fernández-Gutiérrez, Mar; San Román, Julio; Goya, Gerardo; Hernández, Rebeca; Mijangos, Carmen

2014-02-15

105

Design of Chitosan and Its Water Soluble Derivatives-Based Drug Carriers with Polyelectrolyte Complexes  

PubMed Central

Chitosan, the cationic polysaccharide derived from the natural polysaccharide chitin, has been studied as a biomaterial for more than two decades. As a polycationic polymer with favorable properties, it has been widely used to form polyelectrolyte complexes with polyanions for various applications in drug delivery fields. In recent years, a growing number of studies have been focused on the preparation of polyelectrolyte complexes based on chitosan and its water soluble derivatives. They have been considered well-suited as biomaterials for a number of vital drug carriers with targeted/controlled release profiles, e.g., films, capsules, microcapsules. In this work, an overview highlights not only the favorable properties of chitosan and its water soluble derivatives but also the good performance of the polyelectrolyte complexes produced based on chitosan. Their various types of applications as drug carriers are reviewed in detail. PMID:25532565

Wu, Qing-Xi; Lin, Dong-Qiang; Yao, Shan-Jing

2014-01-01

106

Comperative study of catalase immobilization on chitosan, magnetic chitosan and chitosan-clay composite beads.  

PubMed

Catalase was immobilized on chitosan and modified chitosan. Studies were carried out on free-immobilized catalase concerning the determination of optimum temperature, pH, thermal, storage stability, reusability, and kinetic parameters. Optimum temperature and pH for free catalase and catalase immobilized were found as 35°C and 7.0, respectively. After 100 times of repeated tests, the immobilized catalases on chitosan-clay and magnetic chitosan maintain over 50% and 60% of the original activity, respectively. The ease of catalase immobilization on low-cost matrices and good stability upon immobilization in the present study make it a suitable product for further use in the food industry. PMID:23687952

Ba?ak, Esra; Aydemir, Tülin; Dinçer, Ay?e; Becerik, Seda Ç?nar

2013-12-01

107

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

108

Research on thymopentin loaded oral N -trimethyl chitosan nanoparticles  

Microsoft Academic Search

Peptides, although high efficacy and specificity in their physiological function, usually have low therapeutical activities\\u000a due to their poor bioavailability when administrated orally. Nanoparticles have been regarded as a useful vector for targeted\\u000a drug delivery system because they can protect drug from being degraded quickly and pass the gastrointestinal barriers. Here\\u000a we described a novel oral N-trimethyl chitosan nanoparticles formulation

Xiao-jia Yuan; Zhi-rong Zhang; Qing-guo Song; Qin He

2006-01-01

109

Bleomycin Loaded Magnetic Chitosan Nanoparticles as Multifunctional Nanocarriers  

Microsoft Academic Search

Iron oxide (Fe3O4) containing magnetic chitosan nanoparticles were prepared with Concanavalin-A and Bleomycin as multifunctional nanocarriers for the targeted cancer therapy by co-precipitation techniques. The chemical structures of nanoparticles were analyzed by FTIR and the magnetic properties of the nanoparticles were evaluated by electron spin resonance technique and vibrational scanning mangnetometer measurements. The in vitro release profiles of Bleomycin were

Do?a Kavaz; Sedat Odaba?; Eylem Güven; Murat Demirbilek; Emir Baki Denkba?

2010-01-01

110

Pervaporation with chitosan membranes. I. Separation of water from ethylene glycol by a chitosan\\/polysulfone composite membrane  

Microsoft Academic Search

A chitosan\\/polysulfone composite membrane was prepared. The preparation procedure involved dissolution of chitosan in dilute aqueous acetic acid to form chitosan salt, coating of the chitosan salt solution on a porous polysulfone substrate, and regeneration of chitosan by alkaline treatment. The membrane was tested for selective removal of water from aqueous ethylene glycol solutions by pervaporation. The effects of operating

Xianshe Feng; Robert Y. M. Huang

1996-01-01

111

Tubulization with chitosan guides for the repair of long gap peripheral nerve injury in the rat.  

PubMed

Biosynthetic guides can be an alternative to nerve grafts for reconstructing severely injured peripheral nerves. The aim of this study was to evaluate the regenerative capability of chitosan tubes to bridge critical nerve gaps (15 mm long) in the rat sciatic nerve compared with silicone (SIL) tubes and nerve autografts (AGs). A total of 28 Wistar Hannover rats were randomly distributed into four groups (n = 7 each), in which the nerve was repaired by SIL tube, chitosan guides of low (?2%, DAI) and medium (?5%, DAII) degree of acetylation, and AG. Electrophysiological and algesimetry tests were performed serially along 4 months follow-up, and histomorphometric analysis was performed at the end of the study. Both groups with chitosan tubes showed similar degree of functional recovery, and similar number of myelinated nerve fibers at mid tube after 4 months of implantation. The results with chitosan tubes were significantly better compared to SIL tubes (P < 0.01), but lower than with AG (P < 0.01). In contrast to AG, in which all the rats had effective regeneration and target reinnervation, chitosan tubes from DAI and DAII achieved 43 and 57% success, respectively, whereas regeneration failed in all the animals repaired with SIL tubes. This study suggests that chitosan guides are promising conduits to construct artificial nerve grafts. © 2014 Wiley Periodicals, Inc. Microsurgery, 2014. PMID:25471200

Gonzalez-Perez, F; Cobianchi, S; Geuna, S; Barwig, C; Freier, T; Udina, E; Navarro, X

2014-12-01

112

Heterogeneous components of chitosans.  

PubMed

The main objectives of the research were to compare the components of partially N-deacetylated chitins prepared identically from native chitin and a chitin regenerated from a heavily deacetylated chitosan. Additionally, to determine if any of the water-soluble components would serve as substrates in a study of a Chitinase isolated from soy bean hull. The brief heating of suspended chitins in 20% (w/w) NaOH resulted in similar degrees of N-deacetylation, the native chitin giving DAc 0.84 and the regenerated chitin DAc 0.79-0.72, with DAc indicating the proportion of glucosamine residues that are acetylated. Evidence for the nature of the hydrolysis of acetamido groups was provided by analyses of the water-soluble and -insoluble Smith degradation products. The water-soluble fraction derived from the native chitin comprised very small amounts of erythrityl N-acetyl glucosaminoside (GlcNAc1E), erythrityl N,N'-diacetyl chitobioside (GlcNAc2E), and erythrityl N,N',N''-triacetyl chitotrioside (GlcNAc3E), each identified by MALDI-TOF mass spectrometry of the butanoyl derivative. The water-insoluble products, as analyzed by light scattering detection method of their butanoyl esters and corrected for their composition, had a molecular weight (Mw) of 25 kDa, corresponding to about 120 N-acetyl glucosaminyl repeating residues (DPw), contrasting to that of 140 kDa with DPw of 680 for the parent chitin. Much of the decrease in the molecular weight of the polymer occurs by the loss of sugar residues by alkaline peeling at reducing terminals. For the regenerated chitin (DAc 1.0), prepared by N-reacetylation of a commercial chitosan (DAc 0.15), the resulting Smith products comprised erythritol and a series of N-acetyl glucosaminyl erythritol homologues of up to at least 39 N-acetyl glucosaminyl repeating residues, reflecting greater heterogeneity in the hydrolysis of acetamido groups along the polymer chain than what was seen for the native chitin. Of the water-soluble Smith products, GlcNAc5-7E were good substrates for chitinase isolated from soybean hull. PMID:20957998

Yang, Byung Y; Ding, Qiong; Montgomery, Rex

2010-11-01

113

In vitro uptake of lysozyme-loaded liposomes coated with chitosan biopolymer as model immunoadjuvants.  

PubMed

Chitosan binds to negatively charged soy lecithin liposomes by an electrostatic interaction driven by its cationic amino group. This interaction allows developing stable coated vesicles suitable as a targeted carrier and controlled release system for drugs and vaccines. In this work, we studied the effect of chitosan-coated liposomes on the uptake and antigen presentation of hen egg-white lysozyme (HEL) in Peyer's patches peritoneal macrophages isolated from mice. Chitosan-coated liposomes were characterized according to size, zeta potential, and antigen-loading and release properties. Results showed an increase in the positive net charge and size of the liposomes as the concentration of chitosan was increased, suggesting an electrostatic interaction and an effective coating, followed by fluorescence microscopy. About 85% of the antigen loaded remained in the chitosan-coated liposomes after release studies for 4 hours in phosphate-buffered saline. After 4 hours of preincubation with a T-cell hybridoma line cocultured with murine peritoneal macrophages, only trace amounts of interleukin-2 (IL-2) were detected in the cocultures treated with HEL alone, whereas cocultures treated with HEL-liposomes had an important production of IL-2, and the HEL chitosan-coated liposomes had already reached maximum IL-2 expression. Confocal microscopy studies showed that chitosan-coated liposomes had a higher uptake rate of the fluorescently labeled HEL than uncoated liposomal vesicles after 30 minutes of incubation with the peritoneal macrophages. Since uptake by macrophage cells is the first step in vaccination, our results suggest that the chitosan-coated liposomal system is a potential candidate as an immunoadjuvant for vaccine delivery systems. PMID:19514859

Madrigal-Carballo, Sergio; Vila, Amparo O; Sibaja, Maria; Reed, Jess D; Molina, Francisco

2010-03-01

114

Environmental applications of chitosan and its derivatives.  

PubMed

Chitosan originates from the seafood processing industry and is one of the most abundant of bio-waste materials. Chitosan is a by-product of the alkaline deacetylation process of chitin. Chemically, chitosan is a polysaccharide that is soluble in acidic solution and precipitates at higher pHs. It has great potential for certain environmental applications, such as remediation of organic and inorganic contaminants, including toxic metals and dyes in soil, sediment and water, and development of contaminant sensors. Traditionally, seafood waste has been the primary source of chitin. More recently, alternative sources have emerged such as fungal mycelium, mushroom and krill wastes, and these new sources of chitin and chitosan may overcome seasonal supply limitations that have existed. The production of chitosan from the above-mentioned waste streams not only reduces waste volume, but alleviates pressure on landfills to which the waste would otherwise go. Chitosan production involves four major steps, viz., deproteination, demineralization, bleaching and deacetylation. These four processes require excessive usage of strong alkali at different stages, and drives chitosan's production cost up, potentially making the application of high-grade chitosan for commercial remediation untenable. Alternate chitosan processing techniques, such as microbial or enzymatic processes, may become more cost-effective due to lower energy consumption and waste generation. Chitosan has proved to be versatile for so many environmental applications, because it possesses certain key functional groups, including - OH and -NH2 . However, the efficacy of chitosan is diminished at low pH because of its increased solubility and instability. These deficiencies can be overcome by modifying chitosan's structure via crosslinking. Such modification not only enhances the structural stability of chitosan under low pH conditions, but also improves its physicochemical characteristics, such as porosity, hydraulic conductivity, permeability, surface area and sorption capacity. Crosslinked chitosan is an excellent sorbent for trace metals especially because of the high flexibility of its structural stability. Sorption of trace metals by chitosan is selective and independent of the size and hardness of metal ions, or the physical form of chitosan (e.g., film, powder and solution). Both -OH and -NH2 groups in chitosan provide vital binding sites for complexing metal cations. At low pH, -NH3 + groups attract and coagulate negatively charged contaminants such as metal oxyanions, humic acids and dye molecules. Grafting certain functional molecules into the chitin structure improves sorption capacity and selectivity for remediating specific metal ions. For example, introducing sulfur and nitrogen donor ligands to chitosan alters the sorption preference for metals. Low molecular weight chitosan derivatives have been used to remediate metal contaminated soil and sediments. They have also been applied in permeable reactive barriers to remediate metals in soil and groundwater. Both chitosan and modified chitosan have been used to phytoremediate metals; however, the mechanisms by which they assist in mobilizing metals are not yet well understood. In addition, microbes have been used in combination with chitosan to remediate metals (e.g., Cu and Zn) in contaminated soils. Chitosan has also been used to remediate organic contaminants, such as oil-based wastewater, dyes, tannins, humic acids, phenols, bisphenoi-A, p-benzoquinone, organo-phosphorus insecticides, among others. Chitosan has also been utilized to develop optical and electrochemical sensors for in-situ detection of trace contaminants. In sensor technology, naturally-derived chitosan is used primarily as an immobilizing agent that results from its enzyme compatibility, and stabilizing effect on nanoparticles. Contaminant-sensing agents, such as enzymes, microbes and nanoparticles, have been homogeneously immobilized in chitosan gels by using coagulating (e.g., alginate, phosphate) or crosslinking agents (e.g., GA, ECH).

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

2015-01-01

115

Heat-Induced Transfer of Protons from Chitosan to Glycerol Phosphate Produces Chitosan Precipitation and Gelation  

E-print Network

of molar ratios of GP to chitosan glucosamine monomer of 1.25 to 10 and with 0 or 150 mM added monovalent the degree ionization of chitosan (R, the fraction of protonated glucosamine monomer) as a function

Buschmann, Michael

116

Buffer-stable chitosan-polyglutamic acid hybrid nanoparticles for biomedical applications.  

PubMed

In spite of their attractive features, widespread biomedical applications of CS nanoparticles are yet to be realized due to their poor stability in physiological conditions, such as in buffer system at pH 7.4. Buffer-stable chitosan-based hybrid NPs (HNPs) are reported and characterized. Buffer stability is achieved by introducing polyglutamic acid to chitosan. The effect of PGA to CS molar ratio and crosslinking on HNP integrity, buffer stability, and biodegradability are studied. Preliminary in vitro studies are carried out to evaluate targeted uptake efficiency of folate conjugated HNPs. Successful demonstration of buffer stability and cancer cell targeting by HNPs achieves important milestones for chitosan-based nanoparticle technology. PMID:23460363

Malhotra, Astha; Zhang, Xiaolei; Turkson, James; Santra, Swadeshmukul

2013-05-01

117

Generic Films and Fibers from Polysaccharides: Chitosan and Alginate .  

E-print Network

??Chitosan and alginate are both extracted from natural resources, and both are biocompatible, biodegradable, and hydrophilic. Thus, chitosan-alginate biopolymer mixtures have the potential to form… (more)

Boy, Ramiz

2011-01-01

118

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

PubMed Central

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

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

2013-01-01

119

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

120

Chitosan Modification and Pharmaceutical/Biomedical Applications  

PubMed Central

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

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

2010-01-01

121

Characterization of chitosan composites with various clays.  

PubMed

The structural properties, thermal behaviour and mechanical properties of composites of chitosan (Ch) with nanoclay (montmorillonite, MMT) and/or nanoclays after surface modification have been characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA) and a tensile tests. The microstructure obtained by SEM and AFM microscopy for unmodified chitosan and its composites showed that particles are relatively well dispersed in the chitosan matrix. However, the increasing concentration of the chitosan solution from 1% to 2% decreases the homogeneity of the surface of the composites. In the case of chitosan composite with modified nanoclay (contains 25-30 wt.% of octadecylamine), the lack of particles aggregates in polymer matrix independent of the concentration of chitosan solution was observed. Generally, addition of nanoclay after its surface modification improved the mechanical and thermal properties of the composite much more than montmorillonite without modification. PMID:24530323

Lewandowska, Katarzyna; Sionkowska, Alina; Kaczmarek, Beata; Furtos, Gabriel

2014-04-01

122

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

123

Chitosan fibrous scaffolds for cartilage tissue engineering.  

E-print Network

??The biocompatibility of chitosan and its similarity with glycosaminoglycans make it attractive for cartilage engineering despite its limited cell adhesion properties. Structural and chemical characteristics… (more)

Ragetly, Guillaume R.

2010-01-01

124

Simple preparation of chitosan nanofibers from dry chitosan powder by the Star Burst system.  

PubMed

Chitosan nanofibers were easily prepared from dry chitosan powder using the Star Burst system, which employs a high-pressure water jet system. Although the chitosan nanofibers became thinner as the number of Star Burst passes increased, the fiber thickness did not change significantly above 10 passes. Crystallinity and the chitosan nanofiber length decreased after extensive treatment due to the strong collision forces breaking the fibers. The mechanical properties and thermal expansion of the chitosan nanofiber sheets were improved by increasing the number of passes up to 10, but further treatment resulted in a deterioration of these properties. PMID:23911458

Dutta, Ajoy Kumar; Kawamoto, Naoki; Sugino, Gaku; Izawa, Hironori; Morimoto, Minoru; Saimoto, Hiroyuki; Ifuku, Shinsuke

2013-09-12

125

TAT-LHRH conjugated low molecular weight chitosan as a gene carrier specific for hepatocellular carcinoma cells.  

PubMed

To develop a chitosan-based nonviral gene carrier capable of delivering genes specifically into hepatoma cells, a bifunctional peptide composed of the TAT (transactivator of transcription) peptide and luteinizing hormone-releasing hormone (LHRH) was conjugated with low molecular weight chitosan, resulting in a TAT-LHRH-chitosan conjugate (TLC). TLC/DNA nanoparticles (TLCDNPs) were characterized by agarose gel retardation, atomic force microscopy, and dynamic light scattering analysis. In vitro targeting specificity and transfection efficiency were analyzed with a GE IN Cell Analyzer 2000 High-Content Cellular Analysis System. The results demonstrated that TLC had stronger DNA condensing power than unmodified chitosan, and that TLCDNPs were of roughly round shape with average diameter of 70-85 nm and zeta potential of +30 mV and were relatively stable in solution. The in vitro study demonstrated TLC was highly selective for hepatoma cells and essentially nontoxic. PMID:24959076

Liu, Lanxia; Dong, Xia; Zhu, Dunwan; Song, Liping; Zhang, Hailing; Leng, Xigang G

2014-01-01

126

Paraquat-loaded alginate\\/chitosan nanoparticles: Preparation, characterization and soil sorption studies  

Microsoft Academic Search

Agrochemicals are amongst the contaminants most widely encountered in surface and subterranean hydrological systems. They comprise a variety of molecules, with properties that confer differing degrees of persistence and mobility in the environment, as well as different toxic, carcinogenic, mutagenic and teratogenic potentials, which can affect non-target organisms including man. In this work, alginate\\/chitosan nanoparticles were prepared as a carrier

Mariana dos Santos Silva; Daniela Sgarbi Cocenza; Renato Grillo; Nathalie Ferreira Silva de Melo; Paulo Sérgio Tonello; Luciana Camargo de Oliveira; Douglas Lopes Cassimiro; André Henrique Rosa; Leonardo Fernandes Fraceto

2011-01-01

127

Preparation of chitosan nanofibers from completely deacetylated chitosan powder by a downsizing process.  

PubMed

Chitosan nanofibers were easily prepared from fully deacetylated chitosan dry powder using a high-pressure waterjet system. From SEM observation, after 10 cycles of treatment, most of the chitosan had been reduced to homogeneous nanofibers measuring tens of nanometers. On the other hand, further mechanical treatment did not show a significant change. Relative crystallinity of chitosan nanofibers gradually decreased as the number of passes increased since high-pressure waterjet treatment damaged the crystalline region of chitosan nanofibers. The transmittance of the chitosan nanofiber slurry increased steeply, as the number of passes increased, indicating that the chitosan fibers were disintegrated effectively. Viscosity of chitosan nanofiber slurry also showed that the chitosan disintegrated well into nanofibers up to 10 passes. Above 10 passes, disintegration efficiency was saturated. The molecular weights of the nanofibers steeply decreased due to the depolymerization of chitosan by mechanical disintegration. The Young's modulus and tensile strength of chitosan nanofiber sheets were improved as the number of treatments increased, but further treatments deteriorated the tensile strength. PMID:25450540

Aklog, Yihun Fantahun; Dutta, Ajoy Kumar; Izawa, Hironori; Morimoto, Minoru; Saimoto, Hiroyuki; Ifuku, Shinsuke

2015-01-01

128

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

2013-11-01

129

Synthesis and properties of chitosan- N-dextran graft copolymers  

Microsoft Academic Search

Novel chitosan-N-dextran graft copolymers with a degree of substitution (DS) of chitosan varying from 16 to 60% and carrying 9 or 36 glucopyranose units in the grafted dextran chains were synthesized via reductive amination. The chemical structure of the chitosan derivatives was confirmed by FTIR, 1H NMR and XPS spectroscopy, the DS of chitosan was determined from the content of

Ugne Janciauskaite; Vilma Rakutyte; Juozas Miskinis; Ricardas Makuska

2008-01-01

130

Chitosan Biotinylation and Electrodeposition for Selective Protein Assembly  

E-print Network

Chitosan Biotinylation and Electrodeposition for Selective Protein Assembly Xiao-Wen Shi, Yi LiuH-responsive amino- polysaccharide chitosan to guide protein assembly.[1­3] Scheme 1a illustrates that chitosan can by electrochemical proton consumption at a cathode surface.[4­9] Once electrodepos- ited, the chitosan film is stable

Rubloff, Gary W.

131

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

132

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

PubMed

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. PMID:20210443

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

2010-01-01

133

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. PMID:23118539

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

134

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

2013-04-01

135

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

136

Oral Vaccination Based on DNA-Chitosan Nanoparticles against Schistosoma mansoni Infection  

PubMed Central

The development of a vaccine would be essential for the control of schistosomiasis, which is recognized as the most important human helminth infection in terms of morbidity and mortality. A new approach of oral vaccination with DNA-chitosan nanoparticles appears interesting because of their great stability and the ease of target accessibility, besides chitosan immunostimulatory properties. Here we described that chitosan nanoparticles loaded with plasmid DNA encoding Rho1-GTPase protein of Schistosoma mansoni, prepared at different molar ratios of primary amines to DNA phosphate anion (N/P), were able to complex electrostatically with DNA and condense it into positively charged nanostructures. Nanoparticles were able to maintain zeta potential and size characteristics in media that simulate gastric (SGF) and intestinal fluids (SIF). Further in vivo studies showed that oral immunization was not able to induce high levels of specific antibodies but induced high levels of the modulatory cytokine IL-10. This resulted in a significative reduce of liver pathology, although it could not protect mice of infection challenge with S. mansoni worms. Mice immunized only with chitosan nanoparticles presented 47% of protection against parasite infection, suggesting an important role of chitosan in inducing a protective immune response against schistosomiasis, which will be more explored in further studies. PMID:22666171

Oliveira, Carolina R.; Rezende, Cíntia M. F.; Silva, Marina R.; Borges, Olga M.; Pêgo, Ana P.; Goes, Alfredo M.

2012-01-01

137

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

PubMed

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

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

2013-04-01

138

Topical formulations and wound healing applications of chitosan.  

PubMed

Chitosan is being used as a wound-healing accelerator in veterinary medicine. To our knowledge, chitosan enhances the functions of inflammatory cells such as polymorphonuclear leukocytes (PMN) (phagocytosis, production of osteopontin and leukotriene B4), macrophages (phagocytosis, production of interleukin (IL)-1, transforming growth factor beta 1 and platelet derived growth factor), and fibroblasts (production of IL-8). As a result, chitosan promotes granulation and organization, therefore chitosan is beneficial for the large open wounds of animals. However, there are some reported complications of chitosan application. Firstly, chitosan causes lethal pneumonia in dogs which are given a high dose of chitosan. In spite of application of chitosan to various species, this finding is observed only in dogs. Secondly, intratumor injection of chitosan on mice bearing tumor increases the rate of metastasis and tumor growth. Therefore, it is important to consider these effects of chitosan, prior to drug delivery. PMID:11718934

Ueno, H; Mori, T; Fujinaga, T

2001-11-01

139

Preparation of chitosan nanoparticles using methacrylic acid  

Microsoft Academic Search

In this work the preparation of chitosan nanoparticle was investigated using methacrylic acid in different conditions and studied by particle size analyzer, zeta-potential, Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) and transmission electron microscopy (TEM). The particle size was dependent on the chitosan concentration used during the preparation method. Nanoparticles with sizes as small as 60 nm were

Márcia R. de Moura; Fauze A. Aouada; Luiz H. C. Mattoso

2008-01-01

140

Microencapsulated chitosan nanoparticles for lung protein delivery  

Microsoft Academic Search

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

Ana Grenha; Begoña Seijo; Carmen Remuñán-López

2005-01-01

141

Chitosan-modifications and applications: Opportunities galore  

Microsoft Academic Search

Of late, the most bountiful natural biopolymer chitin and chitosan have become cynosure of all party because of an unusual combination of biological activities plus mechanical and physical properties. However applications of chitin are limited due to its inherent insoluble and intractable nature. Chitosan, alkaline hydrolytic derivative of chitin has better solubility profile, less crystallinity and is amenable to chemical

V. K. Mourya; Nazma N. Inamdar

2008-01-01

142

Characterization of calcium carbonate/chitosan composites  

SciTech Connect

The crystal growth of calcium carbonate on a chitosan substrate was achieved using a supersaturated calcium carbonate solution, by using various additives, polyacrylic acid (PAA). Polyacrylic acid modified the chitosan-film surface and promoted the nucleation of calcium carbonate crystals.

Gonsalves, K.E.; Zhang, S. [Univ. of Connecticut, Storrs, CT (United States)

1995-12-31

143

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

PubMed

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

Wang, Jinping; Huang, Guihua

2011-11-01

144

Ultrastructure of Hybrid ChitosanGlycerol Phosphate Blood Clots by Environmental Scanning Electron Microscopy  

E-print Network

Ultrastructure of Hybrid Chitosan­Glycerol Phosphate Blood Clots by Environmental Scanning Electron chitosan; chitosan­glycerol phosphate; biomaterials; blood; glutaraldehyde; paraformaldehyde; environmental scanning electron microscopy; cartilage repair; arthritis ABSTRACT Chitosan-based polymers have been

Buschmann, Michael

145

Assessing Viscoelastic Properties of Chitosan Scaffolds and Validating Sequential and Cyclical Tests.  

E-print Network

??We evaluated and modeled the viscoelastic characteristics of chitosan and chitosan gelatin scaffolds prepared using a freeze-drying technique. Chitosan and chitosan-gelatin solutions (0.5 wt% and… (more)

Ratakonda, Swapnika

2011-01-01

146

Chitosan mouthwash: toxicity and in vivo validation.  

PubMed

A previous study showed that a chitosan mouthwash would be a valid alternative to current mouthwashes as it demonstrated, in vitro, significantly higher antibiofilm activity than two commercial mouthwashes. As such, the aim of this work was to verify the safety of the developed product and to validate, in vivo, the biological activity ascertained in vitro. Chitosan mouthwash safety was evaluated through Ames, MTT and V79 chromosomal aberration assay while antimicrobial activity was evaluated through in vivo assays. The results showed that the chitosan mouthwash was safe, presenting lower cytotoxicity than a commercial mouthwash, and that it effectively reduced viable counts of Streptococcus spp. and Enterococcus spp. by ca. 5.5 log of CFU. Furthermore, in direct comparison with a commercial mouthwash the chitosan mouthwash possessed significantly higher antimicrobial activity. The conjunction of these results proves that the chitosan mouthwash is a safe, effective, natural alternative to the existent chemical mouthwashes. PMID:25037365

Costa, E M; Silva, S; Costa, M R; Pereira, M; Campos, D A; Odila, J; Madureira, A R; Cardelle-Cobas, A; Tavaria, F K; Rodrigues, A S; Pintado, M M

2014-10-13

147

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

2013-03-01

148

Dextran-doxorubicin/chitosan nanoparticles for solid tumor therapy.  

PubMed

Chemotherapy is a major therapeutic approach for the treatment of localized and metastasized cancers. Whereas potent chemotherapeutic agents seem promising in the test tube, clinical trials often fail due to unfavorable pharmacokinetics, poor delivery, low local concentrations, and limited accumulation in the target cell. The pathophysiology of the tumor vasculature and stromal compartment presents a major obstacle to effective delivery of agents to solid tumors. Poor perfusion of the tumor, arterio-venous shunting, necrotic and hypoxic areas, as well as a high interstitial fluid pressure work against favorable drug uptake. Thus, targeted drug delivery using long-circulating particulate drug carriers such as hydrogels of controlled size (<100 nm diameter) holds immense potential to improve the treatment of cancer by selectively providing therapeutically effective drug concentrations at the tumor site [through enhanced permeability and retention (EPR) effect] while reducing undesirable side effects. This review focuses on the progress of targeted delivery of nanoparticulated anticancer drug such as doxorubicin chemically conjugated with dextran and encapsulated in chitosan nanoparticles to solid tumor with reduced side effect of drug. Regulated particle size and long circulation of these hydrogel nanoparticles in blood help them accumulate in tumor tissue through EPR effect as evident from the significant regression of the tumor volume. The cardiotoxicity of doxorubicin can be minimized by coupling the drug with dextran and encapsulating it in chitosan nanoparticles. PMID:20049807

Bisht, Savita; Maitra, Amarnath

2009-01-01

149

Heat-induced transfer of protons from chitosan to glycerol phosphate produces chitosan precipitation and gelation.  

PubMed

Recently, chitosan dissolved in solutions containing glycerol phosphate (GP) were found to undergo a sol-gel transition when heated and the proposed gelling mechanism was based on increasing hydrophobic interactions with temperature. Subsequently, an investigation of ionization and precipitation behavior of chitosan, including dependencies on temperature, added salt, and fraction of deacetylated monomers (fD) was performed. This latter study revealed important differences in the temperature dependence of pKa of chitosan versus GP and led us to propose an alternative hypothesis for the mechanism of gelation in chitosan-GP systems whereby heat induces transfer of protons from chitosan to glycerol phosphate thereby neutralizing chitosan and allowing attractive interchain forces to form a physical gel. To investigate this specific molecular thermogelling mechanism, temperature ramp experiments on dilute chitosan-GP solutions were performed. Chitosans with fD of 0.72 and 0.98 were used to prepare solutions with a range of molar ratios of GP to chitosan glucosamine monomer of 1.25 to 10 and with 0 or 150 mM added monovalent salt. Light transmittance measurements were performed simultaneously to indicate precipitation in these dilute systems as a surrogate for gelation in concentrated systems. Measured temperatures of precipitation ranged from 15 to 85 degrees C, where solutions with less GP (used in a disodium salt form) had lower precipitation temperatures. A theoretical model using acid-base equilibria with temperature dependent pKa's, including the electrostatic contribution from the polyelectrolyte nature of chitosan, was used to calculate the degree ionization of chitosan (alpha, the fraction of protonated glucosamine monomer) as a function of temperature and showed a significant decrease in alpha with increased temperature due to proton transfer from chitosan to GP. This heat-induced proton transfer from chitosan to GP was experimentally confirmed by 31P NMR measurements during temperature ramp experiments since the chemical shift of 31P of GP is an indicator of its level of protonation. By assuming average temperature independent values of alpha p that were calculated from measured T(p), the model was able to accurately predict measured temperatures of precipitation (T(p)) of all chitosan-GP mixtures. The resulting alpha(p) were temperature independent but increased with increased chitosan fD and with increased salt. Measurements and theory revealed that T(p) can be adjusted in a predictable manner by changing the chitosan-GP molar ratio and thereby systematically tailored to obtain a large range of precipitation temperatures. Finally, similar temperature ramp experiments using inorganic phosphate and MES in place of GP demonstrated that the temperature-induced precipitation of chitosan also occurs with these buffers, confirming that the key feature of the buffer used with chitosan is its ability to absorb heat-stimulated release of chitosan protons and facilitate chitosan neutralization. A theoretical expression for the variation of chitosan ionization degree with temperature in a system composed of two titratable species (chitosan and buffer) was derived and allowed us to establish the required characteristics of the buffer for efficient heat-stimulated proton transfer between a chitosan and the buffer. These results provide a useful explanation for the mechanism of heat-induced gelation of chitosan-based systems that could be exploited for numerous practical applications. PMID:18186608

Lavertu, Marc; Filion, Dominic; Buschmann, Michael D

2008-02-01

150

Detection of pathogen Escherichia coli O157:H7 with a wireless magnetoelastic-sensing device amplified by using chitosan-modified magnetic Fe 3O 4 nanoparticles  

Microsoft Academic Search

We report on a wireless magnetoelastic-sensing device for the assay of pathogen with Escherichia coli O157:H7 (E. coli) as a target using chitosan-modified magnetic Fe3O4 nanoparticles (CMNPs) as signal-amplifying tags. At suitable pH the CMNPs, Fe3O4 nanoparticles functionalized with a layer of chitosan, bind to negatively charged E. coli through electrostatic attraction. The E. coli attached CMNPs are magnetically bound

Hailan Lin; Qingzhu Lu; Shutian Ge; Qingyun Cai; Craig A. Grimes

2010-01-01

151

Chitosan modified with gadolinium diethylenetriaminepentaacetic acid for magnetic resonance imaging of DNA\\/chitosan nanoparticles  

Microsoft Academic Search

We have prepared chitosan (CH)–gadolinium (Gd) diethylenetriaminepentaacetic acid (DTPA) conjugates that have potential as contrast agents for magnetic resonance imaging. Conjugates were synthesized starting with low molecular weight chitosan (25kDa and 96% degree of deacetylation (noted DDA)) by covalent linkage of DTPA to chitosan amine groups confirmed by Fourier transform infrared spectroscopy (FTIR). Different DTPA\\/amine ratios were used to obtain

Vincent Darras; Monica Nelea; Françoise M. Winnik; Michael D. Buschmann

2010-01-01

152

Interfacial Properties of Chitosan-PEO Graft Oligomers: Surface Competition with Unmodified Chitosan Oligomers  

Microsoft Academic Search

Oligomers of chitosan carrying 45 units long poly(ethylene oxide), PEO, chains grafted to the\\u000a C-6 position of the sugar units were prepared using a novel synthesis route. The graft density\\u000a was high, close to one poly(ethylene oxide) chain grafted to each sugar unit of the chitosan oligomer\\u000a but a small fraction of unreacted chitosan remained in the sample. The molecular weight distribution

Andra Dedinaite; Joseph Iruthayaraj; Natalija Gorochovceva; Ricardas Makuska; Per M. Claesson

153

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

2009-07-01

154

Gene delivery using chitosan, trimethyl chitosan or polyethylenglycol-graft-trimethyl chitosan block copolymers: Establishment of structure–activity relationships in vitro  

Microsoft Academic Search

Chitosan, trimethyl chitosan or polyethylenglycol-graft-trimethyl chitosan\\/DNA complexes were characterized concerning physicochemical properties such as hydrodynamic diameter, condensation efficiency and DNA release. Furthermore, cytotoxicity of polymers and uptake- and transfection efficiency of polyplexes were evaluated in vitro. Under conditions found in cell culture, formation of aggregates of ?1000 nm and strongly decreased DNA condensation efficiency was observed in the case of chitosan

Oliver Germershaus; Shirui Mao; Johannes Sitterberg; Udo Bakowsky; Thomas Kissel

2008-01-01

155

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

156

Cytotoxic activities of water-soluble chitosan derivatives with different degree of deacetylation.  

PubMed

Chitosans with different degree of deacetylation (DD) (90% and 50% deacetylated chitosan) were prepared by N-deacetylation followed by grafted onto chitosan to form water-soluble aminoethyl-chitosan (AE-chitosan), and dimetylaminoethyl-chitosan (DMAE-chitosan), diethylaminoethyl-chitosan (DEAE-chitosan). In the present study, cytotoxic activities of the chitosan derivatives were evaluated using three tumor cell lines and two normal cell lines, and structure-activity relationship was suggested. The cytotoxic activity was dependent on their DD and substituted group. PMID:16460934

Je, Jae-Young; Cho, Young-Sook; Kim, Se-Kwon

2006-04-15

157

Effects of carboxymethyl chitosan on the blood system of rats  

SciTech Connect

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

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

2011-04-29

158

In Brief. ... Sea Lampreys, Chitosan, and an  

E-print Network

In Brief. ... Sea Lampreys, Chitosan, and an Experimental Oyster Harvester · ...Sea lamprey control in several New York streams according to that state's Department of Environmental Con- servation. Lampreys

159

Chitosan bicomponent nanofibers and nanoporous fibers  

Microsoft Academic Search

Nanofibers with average diameters between 20 and 100nm have been prepared by electrospinning of 82.5% deacetylated chitosan (Mv=1600kDa) mixed with poly(vinyl alcohol) (PVA, Mw=124–186kDa) in 2% (v\\/v) aqueous acetic acid. The formation of bicomponent fibers was feasible with 3% concentration of solution containing up to an equal mass of chitosan. Finer fibers, fewer beaded structures and more efficient fiber formation

Lei Li; You-Lo Hsieh

2006-01-01

160

On the Modification of Chitosan Through Grafting  

Microsoft Academic Search

The feasibility of grafting poly(methyl acrylate) and poly[1-(methoxycarbonyl) ethylene] onto chitosan, poly-?(1?-4)-2-amino-2-deoxy-d-glucose, was investigated. The grafting reaction was carried out in aqueous solution by using ferrous ammonium sulfate (FAS) in combination with H2O2 as redox initiator. The effects of such reaction variables as chitosan, monomer and initiator concentrations, reaction time, and reaction temperature were determined. Through this study the grafting

M. Yazdani-Pedram; A. Lagos; J. Retuert; R. Guerrero; P. Riquelme

1995-01-01

161

Chitosan hydrogel for localized gene silencing  

PubMed Central

Objective To achieve effective delivery of siRNA into target cells in vivo, we have developed a novel approach of siRNA delivery by using local drug delivery systems. Results The chitosan hydrogel (CH-HG) displayed a liquid-solid phase transition in a temperature-dependent manner and formed an endothermic hydrogel in tumor tissue after intra-tumoral injection. Additionally, we tested the extent of in vivo delivery following a single intra-tumoral injection of Alexa555 siRNA/CH-HG into A375SM-bearing mice. The Alexa555 siRNA demonstrated higher localization into tumor cells compared to control. The Alexa555 siRNA delivery extends to tumor cells outside of CH-HG and some tumor cells also infiltrated into CH-HG. For therapeutic proof-of-concept studies, CH-HG including TG2-targeted siRNA significantly inhibited tumor growth in melanoma (A375SM) and breast (MDA-MB231) tumor models compared to control (A375SM: 72% reduction and MDA-MB231: 92% reduction, p < 0.001). Experimental Design We prepared a CH-HG system loaded with siRNA to enhance localized therapeutic efficacy without risk for systemic side effects. Delivery of siRNA into CH-HG was confirmed by fluorescence microscopy. Antitumor efficacy was examined in mouse models of melanoma (A375SM) and breast (MDA-MD231) cancer. Conclusions This study developed a novel local delivery method for siRNA therapy using the CH-HG system. This approach could have broad applications for multiple localized diseases. PMID:21358280

Han, Hee Dong; Mora, Edna M; Roh, Ju Won; Nishimura, Masato; Lee, Sun Joo; Stone, Rebecca L; Bar-Eli, Menashe; Lopez-Berestein, Gabriel

2011-01-01

162

Effect of chitosan molecular weight on rheological behavious of chitosan modified nanoclay at highly hydrated state  

Technology Transfer Automated Retrieval System (TEKTRAN)

Effect of chitosan molecular weight (M(cs)) on the rheological properties of chitosan modified clay (CMCs) at highly hydrated state was investigated. With special emphasis on its effect on the thixotropy of CMCs, the structure recovery at rest after underwent a pre-shearing process was further perfo...

163

Plasticized chitosan/polyolefin films produced by extrusion.  

PubMed

Plasticized chitosan and polyethylene blends were produced through a single-pass extrusion process. Using a twin-screw extruder, chitosan plasticization was achieved in the presence of an acetic acid solution and glycerol, and directly mixed with metallocene polyethylene, mPE, to produce a masterbatch. Different dilutions of the masterbatch (2, 5 and 10 wt% of plasticized chitosan), in the presence of ethylene vinyl acetate, EVA, were subsequently achieved in single screw film extrusion. Very small plasticized chitosan domains (number average diameter <5 ?m) were visible in the polymeric matrix. The resulting films presented a brown color and increasing haze with chitosan plasticized content. Mechanical properties of the mPE films were affected by the presence of plasticized chitosan, but improvement was observed as a result of some compatibility between mPE and chitosan in the presence of EVA. Finally the incorporation of plasticized chitosan affected mPE water vapor permeability while oxygen permeability remained constant. PMID:25498623

Matet, Marie; Heuzey, Marie-Claude; Ajji, Abdellah; Sarazin, Pierre

2015-03-01

164

Hybrid Chitosane-Mercaptopropylsiloxane Films - Synthesis and Properties .  

E-print Network

??A series of new Chitosan=poly(mercaptopropysiloxane) hybrid films were obtained by blending mercaptopropylsiloxane oligomers (pMPS) with chitosan (CHI). The MPS oligomers were prepared by sol-gel using… (more)

Fuentes, S.

2010-01-01

165

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

166

Chitosan-induced programmed cell death in plants  

Microsoft Academic Search

Chitosan, CN?, or H2O2 caused the death of epidermal cells (EC) in the epidermis of pea leaves that was detected by monitoring the destruction of\\u000a cell nuclei; chitosan induced chromatin condensation and marginalization followed by the destruction of EC nuclei and subsequent\\u000a internucleosomal DNA fragmentation. Chitosan did not affect stoma guard cells (GC). Anaerobic conditions prevented the chitosan-induced\\u000a destruction of

L. A. Vasil’ev; E. V. Dzyubinskaya; R. A. Zinovkin; D. B. Kiselevsky; N. V. Lobysheva; V. D. Samuilov

2009-01-01

167

Chitosan-graft-polyethylenimine as a gene carrier  

Microsoft Academic Search

Chitosans have been proposed as biocompatible alternative cationic polymers that are suitable for non-viral delivery. However, the transfection efficiency of chitosan-DNA nanoparticles is still very low. To improve transfection efficiency, we prepared chitosan-graft-polyethylenimine (CHI-g-PEI) copolymer by an imine reaction between periodate-oxidized chitosan and polyethylenimine (PEI). The molecular weight and composition of the CHI-g-PEI copolymer were characterized, using multi-angle laser scattering

Hu-Lin Jiang; You-Kyoung Kim; Rohidas Arote; Jae-Woon Nah; Myung-Haing Cho; Yun-Jaie Choi; Toshihiro Akaike; Chong-Su Cho

2007-01-01

168

Chitosan microspheres as immobilized dye affinity support for catalase adsorption  

Microsoft Academic Search

Chitosan microsphere (CS) was prepared by phase-inversion method as the support matrices. Cibacron Blue F3GA (CB) was covalently attached to the chitosan microspheres, and thus the novel dye-affinity adsorbent was obtained. These Cibacron Blue F3GA-attached chitosan microspheres (CB-CS) were used in the catalase (CAT) adsorption studies. The maximum CAT adsorption capacity of Cibacron Blue F3GA-attached chitosan microspheres was 28.4mg\\/g at

Jingling Shentu; Jianmin Wu; Weihua Song; Zhishen Jia

2005-01-01

169

Nanoparticle uptake and gene transfer efficiency for MSCs on chitosan and chitosan-hyaluronan substrates.  

PubMed

Nanoparticles (NPs) are usually surface modified to increase endocytosis for applications in cellular imaging and gene delivery. The influence of cell culture substrates on endocytosis remains relatively unexplored. This study investigated the substrate-mediated effects on the uptake of NPs by mesenchymal stem cells (MSCs). Two types of NPs were employed, negatively charged paramagnetic iron oxide (Fe(3)O(4)) NPs (~5 nm) and bare plasmid DNA pTRE-Tight-DsRED2 (3.3 kb, ~5 nm), each of which were poorly endocytosed by the adipose-derived MSCs grown on tissue culture polystyrene (TCPS). When cells were cultured on chitosan or hyaluronan-modified chitosan (chitosan-HA) membranes, significant increases (>5-fold) in the intracellular uptake of Fe(3)O(4) NPs as well as transfectability of plasmid DNA were demonstrated. The enhancement in transgene expression was more pronounced than that using the transfection agent. The beneficial effects were not caused by elevated proliferation or a change in the differentiation state of interacting MSCs. On chitosan and chitosan-HA, cells moved fast and formed spheroids. The cytoskeletal arrangement associated with the up-regulated RhoA activity during spheroid formation may have accounted for the increased endocytosis. Using different inhibitors, the endocytosis pathways were further clarified. Both Fe(3)O(4) NPs and plasmid DNA were taken up primarily by clathrin-mediated endocytosis on chitosan (~50%). The caveolae-mediated endocytosis on chitosan-HA was more evident (~30-40%) than that on chitosan (<25%). For plasmid DNA but not Fe(3)O(4) NPs, macropinocytosis also occurred on both substrates. Chitosan and chitosan-HA as cell culture substrates may activate different endocytic pathways of MSCs to increase NP internalization or plasmid transfection. The substrate-mediated endocytosis described here may represent a new and potentially attractive approach to facilitate stem cell labeling or to improve gene delivery efficiency without altering cell viability and differentiation. PMID:22364729

Hsu, Shan-hui; Ho, Tung-Tso; Tseng, Ting-Chen

2012-05-01

170

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

2013-01-01

171

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

PubMed

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

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

2011-04-01

172

Stability studies of chitosan-DNA-FAP-B nanoparticles for gene delivery to lung epithelial cells.  

PubMed

A successful gene delivery system requires efficiency and stability during storage. Stability studies are imperative for nanomedicines containing biotechnological products such as plasmids and targeting peptides. Chitosan-DNA-FAP-B nanoparticles are novel non-viral vectors for specific gene delivery to the lung epithelial cells. In this study, the storage stability of chitosan-DNA-FAP-B nanoparticles at -20, 5 and 24 °C was examined. Size, zeta potential and transfection efficiency of these nano-particles in storage were also evaluated. Stability studies showed that chitosan-DNA-FAP-B nanoparticles were stable after 1 month when stored at -20 °C and retained their initial size, zeta potential and transfection efficiency. However, their stability was not desirable at 5 and 24 °C. Based on these results, it can be concluded that chitosan-DNA-FAP-B nanoparticles can be a promising candidate for gene delivery to lung epithelial cells with good storage stability at -20 °C during 1 month. PMID:22472451

Mohammadi, Zohreh; Dorkoosh, Farid Abedin; Hosseinkhani, Saman; Amini, Tina; Rahimi, Amir Abbas; Najafabadi, Abdolhossein Rouholamini; Tehrani, Morteza Rafiee

2012-03-01

173

Free radical degradation of chitosan with potassium persulfate  

Microsoft Academic Search

A thermal dissociation initiator, potassium persulfate (KPS), is added to the chitosan solution at 70 °C; immediately, the solution viscosity and the molecular weight of chitosan decrease in a very short time. Size exclusion chromatography, nuclear magnetic resonance and electron spin resonance were used to study the degradation mechanism. A free radical degradation mechanism of chitosan by KPS is then proposed.

Shih-Chang Hsu; Trong-Ming Don; Wen-Yen Chiu

2002-01-01

174

Author's personal copy Precise derivatization of structurally distinct chitosans  

E-print Network

Author's personal copy Precise derivatization of structurally distinct chitosans with rhodamine B to date shows that structurally distinct chitosans have reacted inefficiently and unpredictably with fluorescein isothiocyanate (FITC) in an acid­methanol solvent that maintains both chitosan and fluorophore

Buschmann, Michael

175

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

176

A structured chitosan-based platform for biomolecule attachment to solid surfaces: application to DNA microarray preparation.  

PubMed

A structured chemical platform based on chitosan, an amine-rich polysaccharide, is presented as an alternative chemistry to functionalize solid support (in this case, glass slides) for grafting biomolecules. This approach has been adopted for generating arrays using amino-modified oligonucleotides with two different lengths (25-mer and 70-mer) for different purposes. Results using these chitosan-activated surfaces indicate high oligonucleotide loading capacity, good availability to hybridization against targets, and effectiveness in enzyme-mediated single nucleotide polymorphism (SNP) detection procedures by DNA polymerase and DNA ligase enzymes with low background. Universal arrays have been prepared and extensively used with excellent results in different applications. The chitosan-treated surfaces were also evaluated for their performance in a gene expression experiment. PMID:16536468

Consolandi, Clarissa; Severgnini, Marco; Castiglioni, Bianca; Bordoni, Roberta; Frosini, Andrea; Battaglia, Cristina; Bernardi, Luigi Rossi; Bellis, Gianluca De

2006-01-01

177

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

PubMed

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

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

2012-06-01

178

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

179

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

PubMed

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

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

2015-01-01

180

Isolation and characterization of chitin and chitosan from marine origin.  

PubMed

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

Nwe, Nitar; Furuike, Tetsuya; Tamura, Hiroshi

2014-01-01

181

Magnetic chitosan nanoparticles: Studies on chitosan binding and adsorption of Co(II) ions  

Microsoft Academic Search

The magnetic chitosan nanoparticles of 13.5nm were prepared as a magnetic nano-adsorbent by the carboxymethylation of chitosan and the followed binding on the surface of Fe3O4 nanoparticles via carbodiimide activation. Their saturation magnetization, remanent magnetization, coercivity, and squareness were 62emu\\/g, 1.8emu\\/g, 6.0Oe, and 0.029, respectively, reflecting their superparamagnetic property. The binding reaction of carboxymethyl chitosan on the surface of Fe3O4

Yang-Chuang Chang; Song-Wen Chang; Dong-Hwang Chen

2006-01-01

182

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

183

Chitosan in mucoadhesive drug delivery: focus on local vaginal therapy.  

PubMed

Mucoadhesive drug therapy destined for localized drug treatment is gaining increasing importance in today's drug development. Chitosan, due to its known biodegradability, bioadhesiveness and excellent safety profile offers means to improve mucosal drug therapy. We have used chitosan as mucoadhesive polymer to develop liposomes able to ensure prolonged residence time at vaginal site. Two types of mucoadhesive liposomes, namely the chitosan-coated liposomes and chitosan-containing liposomes, where chitosan is both embedded and surface-available, were made of soy phosphatidylcholine with entrapped fluorescence markers of two molecular weights, FITC-dextran 4000 and 20,000, respectively. Both liposomal types were characterized for their size distribution, zeta potential, entrapment efficiency and the in vitro release profile, and compared to plain liposomes. The proof of chitosan being both surface-available as well as embedded into the liposomes in the chitosan-containing liposomes was found. The capability of the surface-available chitosan to interact with the model porcine mucin was confirmed for both chitosan-containing and chitosan-coated liposomes implying potential mucoadhesive behavior. Chitosan-containing liposomes were shown to be superior in respect to the simplicity of preparation, FITC-dextran load, mucoadhesiveness and in vitro release and are expected to ensure prolonged residence time on the vaginal mucosa providing localized sustained release of entrapped model substances. PMID:25574737

Andersen, Toril; Bleher, Stefan; Eide Flaten, Gøril; Tho, Ingunn; Mattsson, Sofia; Škalko-Basnet, Nataša

2015-01-01

184

Chitosan in Mucoadhesive Drug Delivery: Focus on Local Vaginal Therapy  

PubMed Central

Mucoadhesive drug therapy destined for localized drug treatment is gaining increasing importance in today’s drug development. Chitosan, due to its known biodegradability, bioadhesiveness and excellent safety profile offers means to improve mucosal drug therapy. We have used chitosan as mucoadhesive polymer to develop liposomes able to ensure prolonged residence time at vaginal site. Two types of mucoadhesive liposomes, namely the chitosan-coated liposomes and chitosan-containing liposomes, where chitosan is both embedded and surface-available, were made of soy phosphatidylcholine with entrapped fluorescence markers of two molecular weights, FITC-dextran 4000 and 20,000, respectively. Both liposomal types were characterized for their size distribution, zeta potential, entrapment efficiency and the in vitro release profile, and compared to plain liposomes. The proof of chitosan being both surface-available as well as embedded into the liposomes in the chitosan-containing liposomes was found. The capability of the surface-available chitosan to interact with the model porcine mucin was confirmed for both chitosan-containing and chitosan-coated liposomes implying potential mucoadhesive behavior. Chitosan-containing liposomes were shown to be superior in respect to the simplicity of preparation, FITC-dextran load, mucoadhesiveness and in vitro release and are expected to ensure prolonged residence time on the vaginal mucosa providing localized sustained release of entrapped model substances. PMID:25574737

Andersen, Toril; Bleher, Stefan; Flaten, Gøril Eide; Tho, Ingunn; Mattsson, Sofia; Škalko-Basnet, Nataša

2015-01-01

185

Effects of sulfate chitosan derivatives on nonalcoholic fatty liver disease  

NASA Astrophysics Data System (ADS)

Sulfate chitosan derivatives have good solubility and therapeutic effect on the cell model of NAFLD. The aim of this study was to examine the therapeutic effect of sulfate chitosan derivatives on NAFLD. The male Wistar rats were orally fed high fat emulsion and received sulfate chitosan derivatives for 5 weeks to determine the pre-treatment effect of sulfate chitosan derivatives on NAFLD. To evaluate the therapeutic effect of sulfate chitosan derivatives on NAFLD, the rats were orally fed with high concentration emulsion for 5 weeks, followed by sulfate chitosan derivatives for 3 weeks. Histological analysis and biomedical assays showed that sulfate chitosan derivatives can dramatically prevent the development of hepatic steatosis in hepatocyte cells. In animal studies, pre-treatment and treatment with sulfate chitosan derivatives significantly protected against hepatic steatohepatitis induced by high fat diet according to histological analysis. Furthermore, increased TC, ALT, MDA, and LEP in NAFLD were significantly ameliorated by pre-treatment and treatment with sulfate chitosan derivatives. Furthermore, increased TG, AST, and TNF-? in NAFLD were significantly ameliorated by treatment with sulfate chitosan derivatives. Sulfate chitosan derivatives have good pre-treatment and therapeutic effect on NAFLD.

Yu, Mingming; Wang, Yuanhong; Jiang, Tingfu; Lv, Zhihua

2014-06-01

186

Fabrication, characterization and cell cultures on a novel chitosan scaffold.  

PubMed

Chitosan has been used as scaffolds with various methods of fabrication including expensive commercial available ones for tissue engineering. The objective of this study is to assemble our novel method of chitosan scaffold fabrication in economical and uncomplicated way that suitable for dental pulp stem cell (DPSC) and stem cells of human exfoliated deciduous teeth (SHED). Chitosan scaffolds (2% and 3%) were fabricated in an uncomplicated procedure, including centrifugation and freeze-drying steps. The chitosan scaffolds were compared and the pore size, swelling and degradation were assessed. In addition, the cytocompatibility was assessed of chitosan scaffolds seeded with DPSC and SHED. The pore size of 2% and 3% chitosan scaffolds were similar being 188.71±51.90 ?m and 195.30±67.21 ?m, respectively. Swelling ratios of 3% chitosan scaffolds were significantly lower than those of 2% chitosan scaffolds. Dimension of scaffolds changed in first 5 minutes. After that, those scaffolds could maintain their dimension. Chitosan scaffolds degraded as from day 7. No differences were found between 2% and 3% chitosan scaffolds. The scaffolds were shown to be non-toxic and to promote DPSCs and SHED growth. The viability of DPSCs and SHED on 2% scaffolds proved to be higher than that of the 3% scaffold group. This study suggested that chitosan scaffolds fabricated with our novel method were suitable for the growth and survival of DPSC and SHED. PMID:25538063

Guan, Zheng; Shi, Songtao; Samruajbenjakun, Buncha; Kamolmatyakul, Suttatip

2015-01-01

187

Strong adhesion and cohesion of chitosan in aqueous solutions.  

PubMed

Chitosan, a load-bearing biomacromolecule found in the exoskeletons of crustaceans and insects, is a promising biopolymer for the replacement of synthetic plastic compounds. Here, surface interactions mediated by chitosan in aqueous solutions, including the effects of pH and contact time, were investigated using a surface forces apparatus (SFA). Chitosan films showed an adhesion to mica for all tested pH ranges (3.0-8.5), achieving a maximum value at pH 3.0 after a contact time of 1 h (Wad ~ 6.4 mJ/m(2)). We also found weak or no cohesion between two opposing chitosan layers on mica in aqueous buffer until the critical contact time for maximum adhesion (chitosan-mica) was reached. Strong cohesion (Wco ~ 8.5 mJ/m(2)) between the films was measured with increasing contact times up to 1 h at pH 3.0, which is equivalent to ~60% of the strongest, previously reported, mussel underwater adhesion. Such time-dependent adhesion properties are most likely related to molecular or molecular group reorientations and interdigitations. At high pH (8.5), the solubility of chitosan changes drastically, causing the chitosan-chitosan (cohesion) interaction to be repulsive at all separation distances and contact times. The strong contact time and pH-dependent chitosan-chitosan cohesion and adhesion properties provide new insight into the development of chitosan-based load-bearing materials. PMID:24138057

Lee, Dong Woog; Lim, Chanoong; Israelachvili, Jacob N; Hwang, Dong Soo

2013-11-19

188

Strong adhesion and cohesion of chitosan in aqueous solutions  

PubMed Central

Chitosan, a load-bearing biomacromolecule found in the exoskeletons of crustaceans and insects, is a promising biopolymer for the replacement of synthetic plastic compounds. Here, surface interactions mediated by chitosan in aqueous solutions, including the effects of pH and contact time, were investigated using a surface forces apparatus (SFA). Chitosan films showed an adhesion to mica for all tested pH ranges (3.0–8.5), achieving a maximum value at pH 3.0 after a contact time of 1 hr (Wad ~6.4 mJ/m2). We also found weak or no cohesion between two opposing chitosan layers on mica in aqueous buffer until the critical contact time for maximum adhesion (chitosan-mica) was reached. Strong cohesion (Wco ~8.5 mJ/m2) between the films was measured with increasing contact times up to 1 hr at pH 3.0, which is equivalent to ~60% of the strongest, previously reported, mussel underwater adhesion. Such time-dependent adhesion properties are most likely related to molecular or molecular group reorientations and interdigitations. At high pH (8.5), the solubility of chitosan changes drastically, causing the chitosan-chitosan (cohesion) interaction to be repulsive at all separation distances and contact times. The strong contact time and pH-dependent chitosan-chitosan cohesion and adhesion properties provide new insight into the development of chitosan based load-bearing materials. PMID:24138057

Lee, Dong Woog; Lim, Chanoong; Israelachvili, Jacob N.; Hwang, Dong Soo

2014-01-01

189

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. PMID:20695636

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

2010-01-01

190

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. PMID:20957169

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

2010-01-01

191

Chitosan microspheres containing the natural urucum pigment.  

PubMed

An increasing trend in the food and pharmaceutical industries is toward replacing synthetic additives with natural products. However, in this regard, difficulties may be encountered due to the instability of such compounds. Encapsulation has become an important process to protect natural pigments. This paper reports on the encapsulation of the natural urucum pigment with chitosan using different techniques and its release under different pH conditions. The material loaded with pigment was evaluated by infrared spectroscopy, scanning electron microscopy and thermal analysis. Chitosan was found to be an effective encapsulating agent for urucum pigment. No investigations have previously been reported on the relation of chitosan to the stability of encapsulated natural pigments. PMID:16361194

Souza, T C R; Parize, A L; Brighente, I M C; Fávere, V T; Laranjeira, M C M

2005-08-01

192

Structural Characterization of Chitosan-Clay Nanocomposite  

NASA Astrophysics Data System (ADS)

Novel materials originating from renowable sources mainly consist of biopolymers and their composites or nanocomposites. A typical material belonging to this group is chitosane (CS), which is a cationic natural polysaccharide that can be produced by alkaline N-deacetylation of chitine. Chitosane has a variety of applications in biomedical products, cosmetics, and food processing [1, 2].Organic-inorganic hybrid materials basing on chitosane and nanoclay (montmoryllonite, MMT) were characterized by the vibrational spectrocopy methods (Micro-Raman spectroscopy and FT-Raman spectroscopy) and the thermal analysis methods (TG, DSC). It was shown, that small amount on a nanofiller (MMT, 3 wt.%) used to modify the polymer matrix influences the structure of its polymeric chains.

Paluszkiewicz, C.; Weselucha-Birczynska, A.; Stodolak, E.

2010-08-01

193

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

194

Solid polymer electrolyte from phosphorylated chitosan  

SciTech Connect

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

Fauzi, Iqbal, E-mail: arcana@chem.itb.ac.id; Arcana, I Made, E-mail: arcana@chem.itb.ac.id [Inorganic and Physical Chemistry Research Groups, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia)

2014-03-24

195

Effect of Changes in Relative Humidity and Temperature on Ultrathin Chitosan Films  

E-print Network

Effect of Changes in Relative Humidity and Temperature on Ultrathin Chitosan Films Christopher A; Revised Manuscript Received July 4, 2006 We have prepared uniform films of chitosan with thicknesses 20 nm chitosan dissolved in dilute acetic acid onto silicon

Dutcher, John

196

Title of Thesis: CHARACTERIZATION OF ELECTRODEPOSITED CHITOSAN FILMS BY ATOMIC FORCE  

E-print Network

ABSTRACT Title of Thesis: CHARACTERIZATION OF ELECTRODEPOSITED CHITOSAN FILMS BY ATOMIC FORCE W. Rubloff Department of Materials Science and Engineering Chitosan has served as a robust showed fairly smooth distribution of chitosan, whereas dried films were much rougher, indicating non

Anlage, Steven

197

Biomaterials 21 (2000) 2155}2161 Novel injectable neutral solutions of chitosan form  

E-print Network

Biomaterials 21 (2000) 2155}2161 Novel injectable neutral solutions of chitosan form biodegradable solutions based on chitosan/polyol salt combinations is described. These formulations possess with biological compounds. 2000 Elsevier Science Ltd. All rights reserved. Keywords: Chitosan; Glycerophosphate

Buschmann, Michael

198

Mechano-transduction of DNA hybridization and dopamine oxidation through electrodeposited chitosan network{  

E-print Network

Mechano-transduction of DNA hybridization and dopamine oxidation through electrodeposited chitosan sensitivity or selectivity. To address these limitations, we electrodeposited a chitosan film onto a cantilever surface and mechano-transduced detection events through the chitosan network. Our first

Ghodssi, Reza

199

Biodegradation of chitosan-graft-polymethylmethacrylate films  

Microsoft Academic Search

Methylmethacrylate was graft copolymerized onto chitosan, the N-deacetylated derivative of chitin, by persulfate-induced free radical initiation to get chitosan-graft-polymethylmethacrylate (C-g-PMMA), which could be thermo-pressed into thin films. Screening of known microorganisms for in vivo degradation of C-g-PMMA copolymer showed maximum activity (11.3?g glucosamine released min?1ml?1 at 37°C) for Bacillus subtilis. Aspergillus flavus which colonized on C-g-PMMA films was isolated and

K. V. Harish Prashanth; Kshama Lakshman; T. R. Shamala; R. N. Tharanathan

2005-01-01

200

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. PMID:23351907

2012-01-01

201

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

Microsoft Academic Search

In this study, chitosan beads (Ch-bead) and cibacron blue F3GA attached chitosan beads (CB-Ch-bead) were prepared. Their characteristics were investigated with experiments of swelling, thermogravimetric analysis and Fourier transform infrared (FTIR) spectroscopic analysis. Catalase (CAT) was immobilized onto these beads. The adsorption isotherms have a Langmuirian shape for Ch-beads and CB-Ch-beads. The CAT adsorption capacity of Ch-beads is higher than

?enay Akku? Çetinus; H. Nursevin Öztop; Dursun Sarayd?n

2007-01-01

202

Cyclic RGD-modified chitosan/graphene oxide polymers for drug delivery and cellular imaging.  

PubMed

Polymers based on cyclic RGD-modified chitosan/graphene oxide are investigated in this paper as an innovative type of drug delivery system for hepatocellular carcinoma-targeted therapy and imaging. The system was prepared using a simple noncovalent method by coating drug-loaded graphene oxide (GO) with cyclic RGD-modified chitosan (RC). The results show that an efficient loading of doxorubicin (DOX) on GO (1.00mg/mg) was obtained. The system exhibits a pH-responsive behavior because of the hydrogen bonding interaction between GO and RC, and may be very stable under physiological conditions but with release at a lower pH (tumor environment). In addition, cellular uptake and proliferation studies using hepatoma cells (Bel-7402, SMMC-7721, HepG2) indicated that the cRGD-modified chitosan/graphene oxide polymer could recognize hepatoma cells and promote drug uptake by the cells, especially for cells overexpressing integrins. Together, these results demonstrate that the RC/GO polymers provide a multifunctional drug delivery system with the ability to target hepatocarcinoma cells, and are pH-responsive and can be efficiently loaded with a number of therapeutic agents for biomedical applications. PMID:25064484

Wang, Chen; Chen, Binbin; Zou, Meijuan; Cheng, Gang

2014-10-01

203

Mechanical, Bioadhesive Strength and Biological Evaluations of Chitosan films for Wound Dressing  

Microsoft Academic Search

Purpose. To investigate the suitability of chitosan films prepared using two different solvents, acetic acid (Chitosan-AA) and lactic acid (Chitosan- LA), for wound dressing, in comparison with a com- mercial preparation, Omiderm?. Methods. The mechanical and in-vitro bioadhesive strength proper- ties of Chitosan-AA, Chitosan-LA, and Omiderm? were investigated using texture analyzer equipment. The vapour permeability of chitosan films was deter-

Tanveer Ahmad Khan; Kok Khiang Peh; Hung Seng; Ch' ng

204

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

PubMed

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

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

2012-06-26

205

Chitosan-amylopectin/hydroxyapatite and chitosan-chondroitin sulphate/hydroxyapatite composite scaffolds for bone tissue engineering.  

PubMed

Over the past few decades, artificial graft materials for bone tissue engineering are gaining much importance. In this study, tri-component scaffolds of chitosan/natural hydroxyapatite with chondroitin sulfate (chitosan-CS/HAp) and amylopectin (chitosan-AP/HAp) have been developed for the first time via freeze-drying method and were characterized physicochemically for bone grafting substitutes. Chemical interactions and dispersion of HAp, CS and AP in the chitosan matrix have been evaluated by various analytical techniques. The porosity and water uptake/retention ability of these composite scaffolds decreased whereas thermal stability increased when compared to the chitosan scaffold. The pore size of the chitosan/HAp, chitosan-CS/HAp and chitosan-AP/HAp scaffolds varied from 60 to 180 ?m, 60 to 400 ?m and 80 to 500 ?m, respectively. Cell proliferation, alkaline phosphatase activity and type-1 collagen production was evaluated in vitro using MG-63 cell line, which was observed to be higher in the composite scaffolds. Excellent interconnected porosity, controlled biodegradation and enhanced cell proliferation of the novel chitosan-CS/HAp and chitosan-AP/HAp scaffolds suggests that these scaffolds are promising biomaterials for bone tissue engineering. PMID:22947451

Venkatesan, Jayachandran; Pallela, Ramjee; Bhatnagar, Ira; Kim, Se-Kwon

2012-12-01

206

Ultrathin Chitosan Films with Tailored Properties  

NASA Astrophysics Data System (ADS)

Chitosan is a biodegradable polysaccharide derived from seashell waste products. Though abundant, the industrial use of this polymer has up until recently been limited to water treatment products. The high water absorbency and biocompatibility of chitosan have enabled its use as a hydrogel in specialty applications such as wound dressings and drug delivery systems. The most convenient method of processing chitosan is solution casting to form films, since the polymer is soluble in weakly acidic solvents. Based on previous work with synthetic polymers, we have developed a protocol for preparing thin, uniform films of chitosan by spincoating from solution onto silicon substrates. Films with thicknesses between 30 and 600 nm (as measured by ellipsometry) and rms roughnesses of less than 1 nm (as measured by atomic force microscopy) were prepared. After preparation, these films quickly absorb water in the presence of high humidity. Heating of the films to high temperature causes large reductions in film thickness h and index of refraction n. After cooling the films to room temperature, h and n remain constant in the presence of high humidity. Using this simple procedure, we are able to produce films with tailored thickness, optical properties and water absorbency.

Murray, Chris; Stukalov, Oleg; Dutcher, John

2004-03-01

207

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

208

Pervaporation dehydration of isopropanol with chitosan membranes  

Microsoft Academic Search

Homogeneous and composite chitosan based membranes were prepared by the solution casting technique. The membranes were investigated for the pervaporation dehydration of isopropanol-water systems. The effects of feed concentration and temperature on the separation performance of the membranes were studied. In terms of the pervaporation separation index (PSI), the composite membrane was more productive than the homogeneous membrane for pervaporation

M. Ghazali; M. Nawawi; Robert Y. M. Huang

1997-01-01

209

Formation and Characterization of Chitosan Membranes  

Microsoft Academic Search

In this paper, hydrophilic polymer membranes based on macromolecular chitosan networks have been synthesized and characterized. The structure of the membrane has been altered in several ways during the formation to adjust the properties, particularly with regard to the elasticity, tensile strength, permeability, and surface structure. An alteration of the network structure was achieved by addition of flexibilizer, cross-linking with

C. Clasen; T. Wilhelms; W.-M. Kulicke

2006-01-01

210

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

211

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

NASA Astrophysics Data System (ADS)

Nanoscale materials have attracted much attention in the last two decades due to their unique properties. The size effect attains new chemical and physical properties to these materials. Nanoparticles and nanofiber are major component of nanomaterials and they have heavily investigated in the literature for different applications. Nanoparticles could be produced from both metals as well as polymers. Chitosan, which is a natural polymer, can be used as capping agent in the preparation of metallic nanoparticles and itself, can produce nanoparticles. The utilization of nanoparticles and nanofibers for wound dressing materials is a very popular approach. Acquiring antibacterial properties to the wound dressing materials could be obtained either by formulation of nanomaterials composites or direct chemical modification of the substance. To improve the antibacterial properties of chitosan two approaches were applied. First, is through the formulation of chitosan with silver nanoparticles and the formation of nanofiber mats. In this study, the concepts of green chemistry were applied and silver nanoparticles were prepared in high concentration using chitosan as a capping polymer and glucose as a reducing agent. Nanofiber mats of polyvinyl alcohol/chitosan/silvernanoparticles were produced via electrospinning. The antibacterial activity of these fibers shows bactericidal effect against E. coli at low concentrations of Ag-NPs. In the second approach, direct chemical modification of chitosan was performed by grafting of Iodoacetic acid to the amino group at carbon-2. The chemical structure of chitosan Iodoacetamide derivative (CIA) was confirmed by FTIR and H1-NMR. The derivative was amorphous and water soluble at neutral pH. The minimum inhibitory concentration of CIA, against E. coli, was 400ig/mL and the derivative was bacteriostatic after 4h of treatment. Nanofiber mats of polyvinyl alcohol/chitosan/chitosan Iodoacetamide were produced via electrospinning. The antibacterial testing of the nanofiber mats were performed according to AATCC-100 protocol. PVA/CS/CIA system was found to have superior antibacterial action over PVA/CS/thiolchitosan counterparts. In the last part of the thesis, chitosan nanoparticles were prepared; for the first time in the literature instead of Tripolyphosphate (TPP), via ionic crosslinking with hexametaphosphate (HMP). A systematic study was conducted to apply the chitosan/HMP nanoparticles as a hydrophilic drug carrier for protein drugs. Chitosan/HMP systems were found to be unstable in the acidic medium. The optimum complexation conditions were established as pH 5 and the nanoparticles showed better stability at 21 days. Chitosan concentration plays an important role in improving particles stability by increasing zeta potential; however, it adversely affects the particles size. BSA loading capacity of chitosan/HMP was higher, 96.3%, than that of TPP, 91.87%, equivalents due to larger average size.

Abdelgawad, Abdelrahman Mohamed

212

Glycerophosphate-based chitosan thermosensitive hydrogels and their biomedical applications.  

PubMed

Chitosan is non-toxic, biocompatible and biodegradable polysaccharide composed of glucosamine and derived by deacetylation of chitin. Chitosan thermosensitive hydrogel has been developed to form a gel in situ, precluding the need for surgical implantation. In this review, the recent advances in chitosan thermosensitive hydrogels based on different glycerophosphate are summarized. The hydrogel is prepared with chitosan and ?-glycerophosphate or ??-glycerophosphate which is liquid at room temperature and transits into gel as temperature increases. The gelation mechanism may involve multiple interactions between chitosan, glycerophosphate, and water. The solution behavior, rheological and physicochemical properties, and gelation process of the hydrogel are affected not only by the molecule weight, deacetylation degree, and concentration of chitosan, but also by the kind and concentration of glycerophosphate. The properties and the three-dimensional networks of the hydrogel offer them wide applications in biomedical field including local drug delivery and tissue engineering. PMID:25498667

Zhou, Hui Yun; Jiang, Ling Juan; Cao, Pei Pei; Li, Jun Bo; Chen, Xi Guang

2015-03-01

213

Chitosan nanoparticles as a novel delivery system for ammonium glycyrrhizinate.  

PubMed

The ammonium glycyrrhizinate-loaded chitosan nanoparticles were prepared by ionic gelation of chitosan with tripolyphosphate anions (TPP). The particle size and zeta potential of nanoparticles were determined, respectively, by dynamic light scattering (DLS) and a zeta potential analyzer. The effects, including chitosan molecular weight, chitosan concentration, ammonium glycyrrhizinate concentration and polyethylene glycol (PEG) on the physicochemical properties of the nanoparticles were studied. These nanoparticles have ammonium glycyrrhizinate loading efficiency. The encapsulation efficiency decreased with the increase of ammonium glycyrrhizinate concentration and chitosan concentration. The introduction of PEG can decrease significantly the positive charge of particle surface. These studies showed that chitosan can complex TPP to form stable cationic nanoparticles for subsequent ammonium glycyrrhizinate loading. PMID:15848008

Wu, Yan; Yang, Wuli; Wang, Changchun; Hu, Jianhua; Fu, Shoukuan

2005-05-13

214

Chitosan-caseinate bilayer coatings for paper packaging materials.  

PubMed

Papers coated with caseinate and caseinate/chitosan bilayer films were developed. Caseinate, chitosan and caseinate/chitosan films were preliminary characterized by FTIR spectroscopy and thermal stability analyses. The effects of coating weight, caseinate concentration (7%, 10%, and 12%, w/w), and coating application methods (single layer and bilayer) on the physical and mechanical properties of coated papers were studied. Increasing the concentration of caseinate led to a decrease in water vapor permeability (WVP) of the resulting coated paper sheets. Chitosan significantly (p<0.05) increased the elongation at break (%E) of coated paper. However, the application of chitosan as a second layer on wet or dry caseinate films did not significantly affect (p>0.05) the tensile strength (TS) of coated paper. The greatest reduction in paper WVP is achieved by addition of a chitosan layer to the dried preformed caseinate-coated paper. PMID:24274537

Khwaldia, Khaoula; Basta, Altaf H; Aloui, Hajer; El-Saied, Houssni

2014-01-01

215

Antimicrobial Effect of Chitosan Nanoparticles on Streptococcus mutans Biofilms?  

PubMed Central

Nanoparticle complexes were prepared from chitosans of various molecular weights (MW) and degrees of deacetylation (DD). The antimicrobial effect was assessed by the Live/Dead BacLight technique in conjunction with confocal scanning laser microscopy (CSLM) and image analysis. Nanocomplexes prepared from chitosans with high MW showed a low antimicrobial effect (20 to 25% of cells damaged), whereas those prepared from low-MW chitosans showed high antimicrobial effect (>95% of cells damaged). PMID:21498764

Chávez de Paz, Luis E.; Resin, Anton; Howard, Kenneth A.; Sutherland, Duncan S.; Wejse, Peter L.

2011-01-01

216

Energetic and magnetic properties of chitosan with embedded Co clusters  

Microsoft Academic Search

Ab initio DFT simulations of cobalt clusters adsorbed on polymer chitosan molecules with increasing size of both Co clusters and polymer molecules are reported. Small cobalt clusters (CoN, N=2–19 atoms) in the ground state are bound to polymer chitosan molecules containing up to four monomers. The different kinds of binding for Co clusters to chitosan were taken in special attention,

Polina L. Tereshchuk

2011-01-01

217

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

218

Development of monetite/phosphorylated chitosan composite bone cement.  

PubMed

In this article, we report the development of a biodegradable monetite [dicalcium phosphate anhydrous (DCPA), CaHPO4 ]/phosphorylated chitosan (p-chitosan) composite orthopedic cement. The cement pastes showed desirable handling properties, injectability, and washout resistance. The incorporation of p-chitosan powders at 5 wt % shortened the setting time of DCPA and significantly improved the mechanical performance of DCPA cement, increasing the compressive strength almost twice from 11.09 ± 1.85 MPa at 0% chitosan to 23.43 ± 1.47 MPa at 5 wt % p-chitosan. On the other hand, higher p-chitosan content or untreated chitosan incorporation lowered the performance of DCPA cements. The cytocompatibility of the composite cement was investigated in vitro using the preosteoblast cell line MC3T3-E1. An increase in cell proliferation was observed in both DCPA and DCPA-p-chitosan. The results show that both the materials are as cytocompatible as hydroxyapatite. Based on these results, DCPA-p-chitosan composite cement can be considered as potential bone repair material. PMID:23997033

Boroujeni, Nariman Mansouri; Zhou, Huan; Luchini, Timothy J F; Bhaduri, Sarit B

2014-02-01

219

Chitosan-gallic acid films as multifunctional food packaging.  

E-print Network

?? Chitosan is a good candidate for multifunctional food packaging because of its biocompatibility, biodegradability, antibacterial properties, secondary antioxidant activity, film forming ability, resistance to… (more)

Schreiber, Stephanie Beth

2012-01-01

220

Chemical modification of graphite surfaces using chitosan as a mediator  

SciTech Connect

Several techniques for modifying graphite surfaces have been utilized the last two decades. Some of these techniques have a few limitations which include monolayer coverage and nonspecific binding to the graphite surfaces. In this report, we describe a novel approach to modify graphite surfaces using chitosan. The graphite is coated with an acidic chitosan solution. After drying, a chitosan film is formed on the graphite surfaces. Glutaraldehyde is attached to the chitosan through an amide linkage. The desired modifiers which contain amine groups are then attached to the free end of the glutaraldehyde. Utilization of the modified graphite surfaces in paste electrodes will be discussed.

Hatley, M.E.; Albahadily, F.N. [Univ. of Central Oklahoma, Edmond, OK (United States)

1995-12-01

221

Oral gingival delivery systems from chitosan blends with hydrophilic polymers.  

PubMed

Chitosan blends with hydrophilic polymers including polyvinylalcohol (PVA), polyethyleneoxide (PEO) and polyvinylpyrrolidone (PVP), were investigated as candidates for oral gingival delivery systems. The bioavailabilty conferred by the chitosan blend delivery systems, as concluded from dog studies, was shown to be comparable to that based on chitosan alone, especially for those blends involving high molecular weight hydrophilic polymers. Results from differential scanning calorimetry and dynamic mechanical thermal analysis, Fourier transform infrared spectroscopy and tensile testing, indicated that the chitosan/PEO and chitosan/PVP blends showed evidence of miscibility in all blend ratios studied, while the chitosan/PVA blend only showed evidence of interaction for the (50:50) and (80:20) blends, but not for the (20:80) blend. However, even a phase separated system may show interesting and exploitable properties, as evidenced by the tensile testing data for the high molecular weight PVA blend (20:80). The study also indicated that chitosan blends were superior in other properties compared to chitosan alone. These included improved comfort and reduced irritation, ease of processing, improved film quality, improved flexibility, and enhanced dissolution. Blends of chitosan with different hydrophilic polymers could thus be promising candidates for formulation in oral mucosal delivery systems. PMID:12551703

Khoo, Cynthia G L; Frantzich, Sofia; Rosinski, Adam; Sjöström, Maria; Hoogstraate, Janet

2003-01-01

222

Chitosan in nasal delivery systems for therapeutic drugs.  

PubMed

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

Casettari, Luca; Illum, Lisbeth

2014-09-28

223

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

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

224

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

2012-12-01

225

Chemical coupling of thiolated chitosan to preformed liposomes improves mucoadhesive properties  

PubMed Central

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

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

2012-01-01

226

Adsorption of bovin serum albumin (BSA) onto the magnetic chitosan nanoparticles prepared by a microemulsion system  

Microsoft Academic Search

The adsorption characteristics of BSA onto the magnetic chitosan nanoparticles have been investigated in this paper. The magnetic chitosan nanoparticles were prepared by adding the basic precipitant of NaOH solution into a W\\/O microemulsion system. The morphology of magnetic chitosan nanoparticles was observed by transmission electron microscope (TEM). It was found that the diameter of magnetic chitosan nanoparticles was from

Yujun Wang; Xianghua Wang; Guangsheng Luo; Youyuan Dai

2008-01-01

227

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

E-print Network

Enzymatic Grafting of Peptides from Casein Hydrolysate to Chitosan. Potential for Value Tyrosinase was used to initiate the grafting of peptides onto the amine-containing polysaccharide chitosan peptide grafting onto the chitosan backbone. A peptide-modified chitosan derivative was generated

Raghavan, Srinivasa

228

Tyrosinase-Catalyzed Synthesis of a Universal Coil-Chitosan Bioconjugate for Protein Immobilization  

E-print Network

that Kcoil peptide was covalently grafted to amines of chitosan. The ability of Kcoil-chitosan conjugate, demonstrating that grafting to chitosan did not negatively impact binding characteristics of Kcoil peptideTyrosinase-Catalyzed Synthesis of a Universal Coil-Chitosan Bioconjugate for Protein Immobilization

Buschmann, Michael

229

Gelation of Vesicles and Nanoparticles Using Water-Soluble Hydrophobically Modified Chitosan  

E-print Network

chitosan. In particular, hmC can be synthesized by grafting alkyl (e.g., C12) tails onto chitosanGelation of Vesicles and Nanoparticles Using Water-Soluble Hydrophobically Modified Chitosan Yanjun Information ABSTRACT: Hydrophobically modified chitosan (hmC) is a self-assembling polymer that has attracted

Raghavan, Srinivasa

230

Ultrastructure of Hybrid Chitosan-Glycerol Phosphate Blood Clots by Environmental Scanning Electron Microscopy  

E-print Network

Ultrastructure of Hybrid Chitosan-Glycerol Phosphate Blood Clots by Environmental Scanning Electron et al. VERSION 30.12.2006 2 ABSTRACT Chitosan-based polymers have been extensively studied solutions of chitosan in a glycerol phosphate buffer (chitosan-GP) with physiological pH and osmolality were

Buschmann, Michael

231

Electrochimica Acta 51 (2006) 53245333 Electrochemical study of chitosan films deposited  

E-print Network

Electrochimica Acta 51 (2006) 5324­5333 Electrochemical study of chitosan films deposited from 2006 Abstract We report the electrochemical characterization of chitosan films deposited at gold the deposition and electroactivity of chitosan coated gold electrodes. Chitosan films were found to deposit

Rubloff, Gary W.

232

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

E-print Network

RESEARCH PAPER Chitosan Film Containing Poly(D,L-Lactic-Co-Glycolic Acid) Nanoparticles: A Platform Purpose To characterize and evaluate chitosan film containing PLGA nanoparticles (NPs) as a platform into chitosan films. Release of CF and NPs from chitosan and release of FPTX from PLGA NPs were monitored

Sridhar, Srinivas

233

Chitosan microparticles for mucosal vaccination against diphtheria: oral and nasal efficacy studies in mice  

Microsoft Academic Search

In this study, the ability of chitosan microparticles to enhance both the systemic and local immune responses against diphtheria toxoid (DT) after oral and nasal administration in mice was investigated.Firstly, DT was associated to chitosan microparticles to determine antigen loading and release. Then DT loaded chitosan microparticles, DT in phosphate buffered saline (PBS) and empty chitosan microparticles (as controls) were

Inez M. van der Lubben; Gideon Kersten; Marjan M. Fretz; Coen Beuvery; J. Coos Verhoef; Hans E. Junginger

2003-01-01

234

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. PMID:20714426

Pangestuti, Ratih; Kim, Se-Kwon

2010-01-01

235

Synthesis and characterization of folate conjugated chitosan and cellular uptake of its nanoparticles in HT29 cells  

Microsoft Academic Search

Folate–chitosan (FA–CS) conjugates synthesized by coupling FA with CS render new and improved functions because the original properties of CS are maintained and the targeting ligand of FA is incorporated. In this work, FA–CS conjugates were synthesized based on chemical linking of carboxylic group of FA with amino group of CS as confirmed by Fourier transform spectroscopy (FTIR) and nuclear

Puwang Li; Yichao Wang; Fanbo Zeng; Lijue Chen; Zheng Peng; Ling Xue Kong

2011-01-01

236

In Vivo Biocompatibility Study of Electrospun Chitosan Microfiber for Tissue Engineering  

PubMed Central

In this work, we examined the biocompatibility of electrospun chitosan microfibers as a scaffold. The chitosan microfibers showed a three-dimensional pore structure by SEM. The chitosan microfibers supported attachment and viability of rat muscle-derived stem cells (rMDSCs). Subcutaneous implantation of the chitosan microfibers demonstrated that implantation of rMDSCs containing chitosan microfibers induced lower host tissue responses with decreased macrophage accumulation than did the chitosan microfibers alone, probably due to the immunosuppression of the transplanted rMDSCs. Our results collectively show that chitosan microfibers could serve as a biocompatible in vivo scaffold for rMDSCs in rats. PMID:21152326

Kang, Yun Mi; Lee, Bit Na; Ko, Jae Hoon; Kim, Gyeong Hae; Kang, Kkot Nim; Kim, Da Yeon; Kim, Jae Ho; Park, Young Hwan; Chun, Heung Jae; Kim, Chun Ho; Kim, Moon Suk

2010-01-01

237

Antitumor drug Paclitaxel-loaded pH-sensitive nanoparticles targeting tumor extracellular pH  

Microsoft Academic Search

Research efforts have been devoted to demonstrating that the pH-sensitive characteristics of poly NIPAAm\\/chitosan nanoparticles can be applied to targeting tumors. A copolymer of (NIPAAm) and chitosan (4:1, m\\/m) was synthesized, and its drug release characteristics investigated. The results revealed that drug-loaded nanoparticles which encapsulation and loading efficiencies were 85.7% and 9.6%, respectively, exhibited pH-sensitive responses to tumor pH. The

Fan Li; Hong Wu; Hui Zhang; Fei Li; Chun-hu Gu; Qian Yang

2009-01-01

238

Silk grafting with chitosan and crosslinking agents  

Microsoft Academic Search

Chitosan grafting onto silk was tested with three crosslinking agents: trifunctional epoxy resin Araldite DY-T, PEG400 dimethacrylate,\\u000a and glutaraldehyde in acetic as well as in tartaric acid solutions. Operating conditions were studied to obtain a significant\\u000a silk weighting with satisfactory graft yields. With the epoxy crosslinker the weight gain was in the range from 1.8 to 8.8\\u000a % with graft

Franco Ferrero; Monica Periolatto; Sara Burelli; Riccardo A. Carletto

2010-01-01

239

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

PubMed

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

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

2013-01-30

240

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

PubMed

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

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

2011-03-15

241

Human chitotriosidase-catalyzed hydrolysis of chitosan.  

PubMed

Chitotriosidase (HCHT) is one of two family 18 chitinases produced by humans, the other being acidic mammalian chitinase (AMCase). The enzyme is thought to be part of the human defense mechanism against fungal parasites, but its precise role and the details of its enzymatic properties have not yet been fully unraveled. We have studied the properties of HCHT by analyzing how the enzyme acts on high-molecular weight chitosans, soluble copolymers of ?-1,4-linked N-acetylglucosamine (GlcNAc, A), and glucosamine (GlcN, D). Using methods for in-depth studies of the chitinolytic machinery of bacterial family 18 enzymes, we show that HCHT degrades chitosan primarily via an endoprocessive mechanism, as would be expected on the basis of the structural features of its substrate-binding cleft. The preferences of HCHT subsites for acetylated versus nonacetylated sugars were assessed by sequence analysis of obtained oligomeric products showing a very strong, absolute, and a relative weak preference for an acetylated unit in the -2, -1, and +1 subsites, respectively. The latter information is important for the design of inhibitors that are specific for the human chitinases and also provides insight into what kind of products may be formed in vivo upon administration of chitosan-containing medicines or food products. PMID:22192075

Eide, Kristine Bistrup; Norberg, Anne Line; Heggset, Ellinor Bævre; Lindbom, Anne Rita; Vårum, Kjell Morten; Eijsink, Vincent G H; Sørlie, Morten

2012-01-10

242

Chitosan films and blends for packaging material.  

PubMed

An increased interest for hygiene in everyday life as well as in food, feed and medical issues lead to a strong interest in films and blends to prevent the growth and accumulation of harmful bacteria. A growing trend is to use synthetic and natural antimicrobial polymers, to provide non-migratory and non-depleting protection agents for application in films, coatings and packaging. In food packaging, antimicrobial effects add up to the barrier properties of the materials, to increase the shelf life and product quality. Chitosan is a natural bioactive polysaccharide with intrinsic antimicrobial activity and, due to its exceptional physicochemical properties imparted by the polysaccharide backbone, has been recognized as a natural alternative to chemically synthesized antimicrobial polymers. This, associated with the increasing preference for biofunctional materials from renewable resources, resulted in a significant interest on the potential for application of chitosan in packaging materials. In this review we describe the latest developments of chitosan films and blends as packaging material. PMID:25458295

van den Broek, Lambertus A M; Knoop, Rutger J I; Kappen, Frans H J; Boeriu, Carmen G

2015-02-13

243

Rheological characterisation of thermogelling chitosan/glycerol-phosphate solutions  

E-print Network

Rheological characterisation of thermogelling chitosan/glycerol-phosphate solutions A. Chenitea; revised 25 July 2000; accepted 28 July 2000 Abstract In this study we demonstrate that chitosan solutions gel-like precipitation and furthermore that subsequent heating of these solutions induces hydrogel

Buschmann, Michael

244

Glycoconjugated chitosan stabilized iron oxide nanoparticles as a multifunctional nanoprobe  

Microsoft Academic Search

Surface modification of iron oxide nanoparticles (IOPs) with functional polymer can be used for the preparation of multifunction nanoprobes. The present study dealt with the preparation of glycoconjugated chitosan (GC) stabilized IOPs (GC-IOPs). GC was prepared by direct coupling of lactobionic acid (LA) on chitosan. GC was subsequently grafted onto the surface of IOPs to enhance colloid stability. X-ray diffraction

So Min Lee; Eun Soo Yoo; Jin Hyun Choi; Han Do Ghim

2009-01-01

245

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

246

Synthesis and antifungal properties of sulfanilamide derivatives of chitosan.  

PubMed

Sulfanilamide derivatives of chitosan (2-(4-acetamido-2-sulfanimide)-chitosan (HSACS, LSACS), 2-(4-acetamido-2-sulfanimide)-6-sulfo-chitosan (HSACSS, LSACSS) and 2-(4-acetamido-2-sulfanimide)-6-carboxymethyl-chitosan (HSACMCS, LSACMCS)) were prepared using different molecular weights of chitosan (CS), carboxymethyl chitosan (CMCS) and chitosan sulfates (CSS) reacted with 4-acetamidobenzene sulfonyl chloride in dimethylsulfoxide solution. The structures of the derivatives were characterized by FT-IR spectroscopy and elemental analysis, which showed that the substitution degree of sulfanilamide group of HSACS, HSACSS, HSACMCS, LSACS, LSACSS and LSACMCS were 0.623, 0.492, 0.515, 0.576, 0.463 and 0.477, respectively. The solubility of the derivatives (pH<7.5) was higher than that of chitosan (pH<6.5). The antifungal activities of the derivatives against Aiternaria solani and Phomopsis asparagi were evaluated based on the method of Jasso et al. in the experiment. The results indicated that all the prepared sulfanilamide derivatives had a significant inhibiting effect on the investigated fungi in the polymer concentration range from 50 to 500 microg mL(-1). The antifungal activities of the derivatives increased with increasing the molecular weight, concentration or the substitution degree. The sulfanilamide derivatives of CS, CMCS and CSS show stronger antifungal activities than CS, CMCS and CSS. PMID:17765881

Zhong, Zhimei; Chen, Rong; Xing, Ronge; Chen, Xiaolin; Liu, Song; Guo, Zhanyong; Ji, Xia; Wang, Lin; Li, Pengcheng

2007-11-26

247

Electrically Conductive Chitosan/Carbon Scaffolds for Cardiac Tissue Engineering  

PubMed Central

In this work, carbon nanofibers were used as doping material to develop a highly conductive chitosan-based composite. Scaffolds based on chitosan only and chitosan/carbon composites were prepared by precipitation. Carbon nanofibers were homogeneously dispersed throughout the chitosan matrix, and the composite scaffold was highly porous with fully interconnected pores. Chitosan/carbon scaffolds had an elastic modulus of 28.1 ± 3.3 KPa, similar to that measured for rat myocardium, and excellent electrical properties, with a conductivity of 0.25 ± 0.09 S/m. The scaffolds were seeded with neonatal rat heart cells and cultured for up to 14 days, without electrical stimulation. After 14 days of culture, the scaffold pores throughout the construct volume were filled with cells. The metabolic activity of cells in chitosan/carbon constructs was significantly higher as compared to cells in chitosan scaffolds. The incorporation of carbon nanofibers also led to increased expression of cardiac-specific genes involved in muscle contraction and electrical coupling. This study demonstrates that the incorporation of carbon nanofibers into porous chitosan scaffolds improved the properties of cardiac tissue constructs, presumably through enhanced transmission of electrical signals between the cells. PMID:24417502

2015-01-01

248

Biological activities of carbohydrate-branched chitosan derivatives.  

PubMed

Two types of biological activities of the carbohydrate-branched chitosan derivatives were investigated. One is the specific interaction with lectins and bacterium. The other is activation of canine polymorphonuclear leukocyte (PMN) cells. The specific bindings of the L-fucose-branched chitosan derivative with Ulex europaeus agglutinin I (UEA-I) and the N-acetyl-D-glucosamine-branched chitosan derivative with Concanavalin A (Con A) were confirmed by a surface plasmon resonance technique. The specific aggregation of the fluorescence-labeled L-fucose-branched chitosan derivative with Pseudomonas aeruginosa was observed by fluorescent microscopic observation. The aggregation would be attributed to the specific binding between the L-fucose-branched chitosan derivative and PA-II receptor on the cell surface of P. aeruginosa. The influence of the chitosan derivatives on the active oxygen species generation from canine PMN cells was also investigated by the luminol-aided chemiluminescence method. The chemiluminescence responses depended on the degree of substitution and water solubility of the chitosan derivatives. The water-insoluble chitosan derivatives would stimulate the PMN cells by a phagocytosis mechanism, and the water-soluble ones would sensitize the PMN cells by a priming mechanism. PMID:11777384

Morimoto, M; Saimoto, H; Usui, H; Okamoto, Y; Minami, S; Shigemasa, Y

2001-01-01

249

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

250

Effects of steam sterilization on thermogelling chitosan-based gels.  

PubMed

A new thermogelling chitosan-glycerophosphate system has been recently proposed for biomedical applications such as drug and cell delivery. The objectives of this work were to characterize the effect of steam sterilization on the in vitro and in vivo end performances of the gel and to develop a filtration-based method to assess its sterility. Autoclaving 2% (w/v) chitosan solutions for as short as 10 min resulted in a 30% decrease in molecular weight, 3-5-fold decrease in dynamic viscosity, and substantial loss of mechanical properties of the resulting gel. However, sterilization did not impair the ability of the system to form a gel at 37 degrees C. The antimicrobial activity of chitosan against several microorganisms was evaluated after inoculation of chitosan solutions and removal of the cells by filtration. It was found that, although chitosan was bacteriostatic against the heat sterilization bioindicator Bacillus stearothermophilus, the bacteria could rapidly grow after separation from the chitosan solution by filtration. This indicated that B. stearothermophilus is an adequate strain to validate a heat sterilization method on chitosan preparations, and accordingly this strain was used to assess the sterility of chitosan solution following a 10 min autoclaving time. PMID:11153009

Jarry, C; Chaput, C; Chenite, A; Renaud, M A; Buschmann, M; Leroux, J C

2001-01-01

251

Preparation of Fe 3O 4–chitosan nanoparticles used for hyperthermia  

Microsoft Academic Search

The Fe3O4–chitosan nanoparticles with core-shell structure have been prepared by crosslinking method. Oleic acid modified Fe3O4 nanoparticles were firstly prepared by co-precipitation then chitosan was added to coat on the surface of the Fe3O4 nanoparticles by physical absorption. The Fe3O4–chitosan nanoparticles were obtained by crosslinking the amino groups on the chitosan using glutaraldehyde. Transmission electron microscopy showed that the Fe3O4–chitosan

Jingmiao Qu; Guang Liu; Yiming Wang; Ruoyu Hong

2010-01-01

252

Some chitin\\/chitosan derivatives for corrosion protection and waste water treatments  

Microsoft Academic Search

Chitin was extracted from locally collected shrimp shells. Chitosan was produced by alkali deacetylation of chitin. Poly(DEAEMA)-chitosan-graft-copolymer, poly(COOH)-chitosan-graft-copolymer, poly(V-OH)-chitosan-graft-copolymer, and carboxymethyl-chitosan were prepared. The extent of the preparation reactions was expressed as nitrogen content, carboxylic content and graft yield. The ability of the prepared compounds to adsorb heavy metals ions and some dyestuffs was studied. The prepared compounds were also

Sanaa M. El-Sawy; Yosreya M. Abu-Ayana; Fikry A. Abdel-Mohdy

2001-01-01

253

Investigation of the therapeutic efficacy of codelivery of psiRNA-vascular endothelial growth factor and pIL-4 into chitosan nanoparticles in the breast tumor model.  

PubMed

Angiogenesis has been known to increase tumor growth and for its metastatic potential in human tumors. Vascular endothelial growth factor (VEGF) plays an important role in tumor angiogenesis and is a promising therapeutic target for breast cancer. VEGF is an essential target for RNAi-based gene therapy of breast cancer. Interleukin-4 (IL-4) may act as an anti-angiogenic molecule that inhibits tumor growth and migration in rats. The purpose of the present study was to improve therapeutic efficacy in breast cancer with the codelivery of siRNA-expressing plasmid targeting VEGF and IL-4-expressing plasmid encapsulating into chitosan nanoparticles (NPs). The codelivery of psiVEGF and pIL-4 plasmids greatly enhanced in vitro and in vivo gene-silencing efficiency. For the in vitro study, when psiVEGF and pIL-4 into chitosan NPs were combined (81%), the gene-silencing effect was higher than psiVEGF and pIL-4 NPs alone. The in vivo study breast tumor model demonstrated that the administration of coencapsulation of psiVEGF and pIL-4 into chitosan NPs caused an additive effect on breast tumor growth inhibition (97%), compared with containing NPs psiVEGF or pIL-4 alone. These results indicate that chitosan NPs can be effectively used for the codelivery of pIL-4 and siVEGF-expressing plasmid in a combination therapy against breast cancer. PMID:24357345

?alva, Emine; Turan, Suna O; Kabasakal, Levent; Alan, Saadet; Özkan, Naziye; Eren, Fatih; Akbu?a, Jülide

2014-03-01

254

Antimicrobial coating of modified chitosan onto cotton fabrics  

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

255

Chitosan magnetic microspheres for technological applications: Preparation and characterization  

NASA Astrophysics Data System (ADS)

One of the major applications of chitosan and its many derivatives are based on its ability to bind strongly heavy and toxic metal ions. In this study chitosan magnetic microspheres have been synthesized. Acetic acid (1%w/v) solution was used as solvent for the chitosan polymer solution (2%w/v) where magnetite nanoparticles were suspended in order to obtain a stable ferrofluid. Glutaraldehyde was used as cross-linker. The magnetic characteristic of these materials allows an easy removal after use if is necessary. The morphological characterization of the microspheres shows that they can be produced in the size range 800-1100 ?m. The adsorption of Cu(II) onto chitosan-magnetite nanoparticles was studied in batch system. A second-order kinetic model was used to fit the kinetic data, leading to an equilibrium adsorption capacity of 19 mg Cu/g chitosan.

Podzus, P. E.; Daraio, M. E.; Jacobo, S. E.

2009-10-01

256

Active naringin-chitosan films: impact of UV irradiation.  

PubMed

Bioactive citrus extract-chitosan films were prepared through solvent casting-evaporation method. The impact of near UV irradiation was studied to reach a better understanding of the film behavior. The antimicrobial activity of films against Listeria innocua was maintained after UV irradiation. To study the interaction between chitosan and citrus extract components, naringin (main component) was selected as the model compound. UV treatment caused modifications of the flavanone regardless of the solvent used for its dissolution, depending on the concentration of naringin in the film: the greater the concentration the lower the modification. DSC results suggested cross-links due to UV irradiation and interactions between naringin and chitosan. This was confirmed by a decrease in the naringin release from the irradiated samples. Naringin- and citrus extract-chitosan films showed an increased absorbance in the UV region compared to pure chitosan films, showing potentiality for decreasing the lipid oxidation induced by UV light in foodstuffs. PMID:24906769

Iturriaga, Leire; Olabarrieta, Idoia; Castellan, Alain; Gardrat, Christian; Coma, Véronique

2014-09-22

257

Immobilization of "Disguised" yeast in chemically crosslinked chitosan beads.  

PubMed

A new simple method for the preparation of chemically crosslinked chitosan beads is presented. It consists of the dropwise addition of 2-3% (w/v) low molecular weight chitosan solution containing 2% (w/v) glyoxal in 1% (w/v) tetrasodiumdiphosphate, pH 8.0. Immobilized viable baker's yeast (Saccharomyces cerevisiae) could be obtained via gel entrapment within the new beads when means preventing their direct contact with soluble chitosan were provided, "disguising" the cells until gelation and crosslinking were completed. Such means included cell suspension in castor oil or mixing with carboxymethyl-cellulose powder. Application of these means was shown to be necessary, as cells exposed to soluble chitosan immediately lost their viability and glycolytic activity. Yeast disguised in castor oil was also protected from bead reinforcement by glutaraldehyde treatment, significantly strengthening bead stability while operating under acidic conditions. This capability was demonstrated by continuous ethanol production by chitosan entrapped yeast. PMID:18623025

Freeman, A; Dror, Y

1994-11-01

258

Chitosan Dermal Substitute and Chitosan Skin Substitute Contribute to Accelerated Full-Thickness Wound Healing in Irradiated Rats  

PubMed Central

Wounds with full-thickness skin loss are commonly managed by skin grafting. In the absence of a graft, reepithelialization is imperfect and leads to increased scar formation. Biomaterials can alter wound healing so that it produces more regenerative tissue and fewer scars. This current study use the new chitosan based biomaterial in full-thickness wound with impaired healing on rat model. Wounds were evaluated after being treated with a chitosan dermal substitute, a chitosan skin substitute, or duoderm CGF. Wounds treated with the chitosan skin substitute showed the most re-epithelialization (33.2 ± 2.8%), longest epithelial tongue (1.62 ± 0.13?mm), and shortest migratory tongue distance (7.11 ± 0.25?mm). The scar size of wounds treated with the chitosan dermal substitute (0.13 ± 0.02?cm) and chitosan skin substitute (0.16 ± 0.05?cm) were significantly decreased (P < 0.05) compared with duoderm (0.45 ± 0.11?cm). Human leukocyte antigen (HLA) expression on days 7, 14, and 21 revealed the presence of human hair follicle stem cells and fibroblasts that were incorporated into and surviving in the irradiated wound. We have proven that a chitosan dermal substitute and chitosan skin substitute are suitable for wound healing in full-thickness wounds that are impaired due to radiation. PMID:24324974

Mohd Hilmi, Abu Bakar; Halim, Ahmad Sukari; Jaafar, Hasnan; Asiah, Abu Bakar; Hassan, Asma

2013-01-01

259

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. PMID:23209848

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

2012-01-01

260

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

E-print Network

is a linear cationic biopolymer composed of glucosamine and N-acetyl-glucosamine that is only soluble, salt, chitosan concentration, and fD, where fD is the fraction of glucosamine monomers (deacetylatedM of its glucosamine monomer and with 0 to 150 mM added salt. Light transmittance measurements were

Buschmann, Michael

261

Book Chapter in Strategies for Cartilage Repair, Ed. RJ Williams, Pub. Humana Press CARTILAGE REPAIR WITH CHITOSAN/GLYCEROL-PHOSPHATE  

E-print Network

REPAIR WITH CHITOSAN/GLYCEROL-PHOSPHATE STABILISED BLOOD CLOTS Michael D. Buschmann1 , Caroline D, Quebec, Canada Keywords : Cartilage Repair, Chitosan, Microfracture, Osteoarthritis Address is a physiological solution of chitosan (a natural polysaccharide containing glucosamine residues) in a buffer

Buschmann, Michael

262

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

Microsoft Academic Search

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

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

2004-01-01

263

Rheological and structural studies of carboxymethyl derivatives of chitosan  

NASA Astrophysics Data System (ADS)

The degrees of substitution of chitosan derivatives were varied and the viscoelastic behavior of these biopolymer solutions was studied using rheology. Chitosan is a cationic copolymer of glucosamine and N-acetylglucosamine obtained by alkaline deacetylation of chitin. Due to its inherent non-toxicity, biocompatibility, and biodegradability, chitosan has gained much interest. However, the poor solubility of the biopolymer in water and most common organic solvents limits its applications. Therefore, the focus of this work is the chemical modification of chitosan via carboxymethylation as well as studying the viscoelastic behavior of these polymer solutions. Varying degrees of substitution (DS) of carboxymethyl chitosan derivatives were synthesized by treating chitosan with monochloroacetic acid under alkylated medium varying the reaction time and temperature. The effect of degree of substitution on the rheology of these polymer solutions was studied as a function of concentration. The viscosity of chitosan derivatives sharply increased with increase in degree of substitution. G' and G" dependence on strain and angular frequency were studied and were found to exhibit predominantly viscous behavior. Additional characterization of the derivatized products were further studied using Fourier transform infrared (FT-IR), 1H Nuclear Magnetic Resonance (1H NMR) spectroscopy, X-ray diffraction (XRD), and thermal gravimetric analysis as well as differential scanning calorimetry (DSC). Degree of substitution (DS) was calculated by titrimetric method.

Winstead, Cherese; Katagumpola, Pushpika

2014-05-01

264

Novel electrohydrodynamic preparation of porous chitosan particles for drug delivery.  

PubMed

Uniform spherical chitosan particles of size <10 microm in diameter are important in drug delivery applications due to their excellent biocompability and biodegradability. A high concentration of chitosan in the particles can help to control the release of drugs and methods for processing high viscosity chitosan solutions are therefore required. In principle, any type of polymer, whether hydrophobic or hydrophilic, can be electrosprayed to obtain monodisperse particles of diameter <10 microm. In practice, however, electrospraying of biopolymers having viscosities of >100 mPa s results in particles >10 microm diameter. In this study, by reducing surface tension of a high viscosity chitosan suspension, it was found that smaller diameter particles could be prepared. Chitosan solutions were electrosprayed in the stable cone-jet mode to systematically study the relationship between particle diameter, viscosity and surface tension. Increasing viscosity resulted in larger diameter particles with a broad size distribution, but decreasing surface tension had the opposite effect. Results show that a chitosan solution having a viscosity of approximately 80 mPa s can be used to prepare chitosan particles of diameter approximately 2.5 microm which on drying reduced to particles of 500 nm. PMID:19034624

Pancholi, Ketan; Ahras, Nassim; Stride, Eleanor; Edirisinghe, Mohan

2009-04-01

265

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

266

Chitosan-based nanofibrous membranes for antibacterial filter applications.  

PubMed

Nanofibrous membranes have drawn considerable interest for filtration applications due to their ability to withstand high fluid flux while removing micro- and nano-sized particulates from solution. The desire to introduce an antibacterial function into water filter applications presents a challenge to widespread application of fibrous membranes because the addition of chemicals or biocides may produce harmful byproducts downstream. Here, we report the development of chitosan-polycaprolactone (PCL) nanofibrous membranes to utilize the natural antibacterial property of chitosan for antibacterial water filtration. Chitosan-PCL fibers with diameters of 200-400 nm and chitosan contents of 25, 50 and 75 wt% were prepared by electrospinning. In a series of bacterial challenge tests, chitosan-PCL fibrous membranes significantly reduced Staphylococcus aureus adhesion compared to PCL fibrous membranes. In water permeability and particulate size removal tests, fibrous membranes with 25% chitosan supported the greatest water flux (?7000 L/h/m(2)) with 100% removal of 300-nm particulates, while maintaining the membrane integrity. This study demonstrates the potential of chitosan-PCL nanofibrous membranes as pre-filters for water filtration systems that demonstrate combinatorial filtration and intrinsic antibacterial advantages. PMID:23218292

Cooper, Ashleigh; Oldinski, Rachael; Ma, Hongyan; Bryers, James D; Zhang, Miqin

2013-01-30

267

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

268

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

269

Rheological and structural studies of carboxymethyl derivatives of chitosan  

SciTech Connect

The degrees of substitution of chitosan derivatives were varied and the viscoelastic behavior of these biopolymer solutions was studied using rheology. Chitosan is a cationic copolymer of glucosamine and N-acetylglucosamine obtained by alkaline deacetylation of chitin. Due to its inherent non-toxicity, biocompatibility, and biodegradability, chitosan has gained much interest. However, the poor solubility of the biopolymer in water and most common organic solvents limits its applications. Therefore, the focus of this work is the chemical modification of chitosan via carboxymethylation as well as studying the viscoelastic behavior of these polymer solutions. Varying degrees of substitution (DS) of carboxymethyl chitosan derivatives were synthesized by treating chitosan with monochloroacetic acid under alkylated medium varying the reaction time and temperature. The effect of degree of substitution on the rheology of these polymer solutions was studied as a function of concentration. The viscosity of chitosan derivatives sharply increased with increase in degree of substitution. G' and G' dependence on strain and angular frequency were studied and were found to exhibit predominantly viscous behavior. Additional characterization of the derivatized products were further studied using Fourier transform infrared (FT-IR), {sup 1}H Nuclear Magnetic Resonance ({sup 1}H NMR) spectroscopy, X-ray diffraction (XRD), and thermal gravimetric analysis as well as differential scanning calorimetry (DSC). Degree of substitution (DS) was calculated by titrimetric method.

Winstead, Cherese; Katagumpola, Pushpika [Delaware State University, Department of Chemistry, 1200 N. Dupont Highway, Dover, DE 19901 (United States)

2014-05-15

270

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

PubMed

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

Zhu, Weili; Zhang, Zhanjun

2014-09-01

271

One-Step Analysis of DNA/Chitosan Complexes by Field-Flow Fractionation Reveals Particle Size and Free Chitosan Content  

E-print Network

One-Step Analysis of DNA/Chitosan Complexes by Field-Flow Fractionation Reveals Particle Size and Free Chitosan Content Pei Lian Ma, Michael D. Buschmann, and Franc¸oise M. Winnik*, Department with chitosan was analyzed by asymmetrical flow field flow fractionation (AF4) with online UV

Buschmann, Michael

272

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

2010-07-01

273

Preparation and characterization of magnetic nanoparticles with chitosan coating  

NASA Astrophysics Data System (ADS)

Magnetic chitosan nanoparticles were prepared by the suspension cross-linking technique for use in the application of magnetic carrier technology. The Fe3O4 magnetic nanoparticles were synthesized by co-precipitation of FeCl2 and FeCl3 solution in base medium for using in the preparation of the magnetic chitosan. The morphological and magnetic properties of the magnetic nanoparticles were characterized by different techniques (TEM, XRD, VSM, FTIR, etc.). The magnetic properties of chitosan - magnetic nanoparticles were analyzed by VSM, and MS around 15 emu/g.

Dung, Doan Thi Kim; Hoang Hai, Tran; Phuc, Le Hong; Long, Bui Duc; Khanh Vinh, Le; Nha Truc, Phan

2009-09-01

274

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

275

Chitosan-based therapeutic nanoparticles for combination gene therapy and gene silencing of in vitro cell lines relevant to type 2 diabetes.  

PubMed

Glucagon like peptide 1 (GLP-1), a blood glucose homeostasis modulating incretin, has been proposed for the treatment of type 2 diabetes mellitus (T2DM). However, native GLP-1 pharmacokinetics reveals low bioavailability due to degradation by the ubiquitous dipeptydil peptidase IV (DPP-IV) endoprotease. In this study, the glucosamine-based polymer chitosan was used as a cationic polymer-based in vitro delivery system for GLP-1, DPP-IV resistant GLP-1 analogues and siRNA targeting DPP-IV mRNA. We found chitosans to form spherical nanocomplexes with these nucleic acids, generating two distinct non-overlapping size ranges of 141-283 nm and 68-129 nm for plasmid and siRNA, respectively. The low molecular weight high DDA chitosan 92-10-5 (degree of deacetylation, molecular weight and N:P ratio (DDA-Mn-N:P)) showed the highest plasmid DNA transfection efficiency in HepG2 and Caco-2 cell lines when compared to 80-10-10 and 80-80-5 chitosans. Recombinant native GLP-1 protein levels in media of transfected cells reached 23 ng/L while our DPP-IV resistant analogues resulted in a fivefold increase of GLP-1 protein levels (115 ng/L) relative to native GLP-1, and equivalent to the Lipofectamine positive control. We also found that all chitosan-DPP-IV siRNA nanocomplexes were capable of DPP-IV silencing, with 92-10-5 being significantly more effective in abrogating enzymatic activity of DPP-IV in media of silenced cells, and with no apparent cytotoxicity. These results indicate that specific chitosan formulations may be effectively used for the delivery of plasmid DNA and siRNA in a combination therapy of type 2 diabetes. PMID:22085632

Jean, Myriam; Alameh, Mohamad; De Jesus, Diogo; Thibault, Marc; Lavertu, Marc; Darras, Vincent; Nelea, Monica; Buschmann, Michael D; Merzouki, Abderrazzak

2012-01-23

276

Chitosan derived formulations and EmzaloidTM technology for mucosal vaccination against diphtheria : nasal efficacy in mice / Erika M. Truter.  

E-print Network

??Previous studies have demonstrated that chitosan and its derivative, N-trimethyl chitosan chloride (TMC) are effective and safe absorption enhancers to improve mucosal delivery of macromolecular… (more)

Truter, Erika Mare

2005-01-01

277

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

2012-01-01

278

Validation of a Janus role of methotrexate-based PEGylated chitosan nanoparticles in vitro  

PubMed Central

Recently, methotrexate (MTX) has been used to target to folate (FA) receptor-overexpressing cancer cells for targeted drug delivery. However, the systematic evaluation of MTX as a Janus-like agent has not been reported before. Here, we explored the validity of using MTX playing an early-phase cancer-specific targeting ligand cooperated with a late-phase therapeutic anticancer agent based on the PEGylated chitosan (CS) nanoparticles (NPs) as drug carriers. Some advantages of these nanoscaled drug delivery systems are as follows: (1) the NPs can ensure minimal premature release of MTX at off-target site to reduce the side effects to normal tissue; (2) MTX can function as a targeting ligand at target site prior to cellular uptake; and (3) once internalized by the target cell, the NPs can function as a prodrug formulation, releasing biologically active MTX inside the cells. The (MTX?+?PEG)-CS-NPs presented a sustained/proteases-mediated drug release. More importantly, compared with the PEG-CS-NPs and (FA?+?PEG)-CS-NPs, the (MTX?+?PEG)-CS-NPs showed a greater cellular uptake. Furthermore, the (MTX?+?PEG)-CS-NPs demonstrated a superior cytotoxicity compare to the free MTX. Our findings therefore validated that the MTX-loaded PEGylated CS-NPs can simultaneously target and treat FA receptor-overexpressing cancer cells. PMID:25114653

2014-01-01

279

Validation of a Janus role of methotrexate-based PEGylated chitosan nanoparticles in vitro  

NASA Astrophysics Data System (ADS)

Recently, methotrexate (MTX) has been used to target to folate (FA) receptor-overexpressing cancer cells for targeted drug delivery. However, the systematic evaluation of MTX as a Janus-like agent has not been reported before. Here, we explored the validity of using MTX playing an early-phase cancer-specific targeting ligand cooperated with a late-phase therapeutic anticancer agent based on the PEGylated chitosan (CS) nanoparticles (NPs) as drug carriers. Some advantages of these nanoscaled drug delivery systems are as follows: (1) the NPs can ensure minimal premature release of MTX at off-target site to reduce the side effects to normal tissue; (2) MTX can function as a targeting ligand at target site prior to cellular uptake; and (3) once internalized by the target cell, the NPs can function as a prodrug formulation, releasing biologically active MTX inside the cells. The (MTX + PEG)-CS-NPs presented a sustained/proteases-mediated drug release. More importantly, compared with the PEG-CS-NPs and (FA + PEG)-CS-NPs, the (MTX + PEG)-CS-NPs showed a greater cellular uptake. Furthermore, the (MTX + PEG)-CS-NPs demonstrated a superior cytotoxicity compare to the free MTX. Our findings therefore validated that the MTX-loaded PEGylated CS-NPs can simultaneously target and treat FA receptor-overexpressing cancer cells.

Luo, Fanghong; Li, Yang; Jia, Mengmeng; Cui, Fei; Wu, Hongjie; Yu, Fei; Lin, Jinyan; Yang, Xiangrui; Hou, Zhenqing; Zhang, Qiqing

2014-07-01

280

Synthesis and Characterization of Biodegradable Ultrasonicated Films made from Chitosan/al2o3 Polymer Nanocomposites  

NASA Astrophysics Data System (ADS)

Chitosan is a biopolymer which is biodegradable, biocompatible, non toxic and cationic in nature. Due to these interesting properties, it finds advanced applications in sensors, drug delivery vehicle and gene therapy etc., In this present work, the biocompatible Al2O3 Nano particles were embedded into Chitosan Polymer matrix by ultrasonication route. XRD and FTIR studies confirm the presence of Al2O3 nanoparticle in the Chitosan polymer matrix. The morphological, optical, electrical properties of the polymer nano composite films are carried out by employing scanning electron microscopy (SEM), UV- Vis, LCR and Impedance studies.

Prakash, B.; Jothirajan, M. A.; Umapathy, S.; Amala, Viji

281

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

282

Development of a gadolinium-loaded liquid scintillator for the Hanaro short baseline prototype detector  

NASA Astrophysics Data System (ADS)

We propose a new experiment on the site of the Korea Atomic Energy Research Institute (KAERI) located at Daejeon, Korea. The Hanaro short baseline (SBL) nuclear reactor with a thermal power output 30 MW is used to investigate a reactor neutrino anomaly. A Hanaro SBL prototype detector having a 60- l volume has been constructed ˜6 m away from the reactor core. A gadolinium (Gd)-loaded liquid scintillator (LS) is used as an active material to trigger events. The selection of the LS is guided by physical and technical requirements, as well as safety considerations. A linear alkyl benzene (LAB) is used as a base solvent of the Hanaro SBL prototype detector. Three g/ l of PPO and 30 mg/ l of bis-MSB are dissolved to formulate the LAB-based LS. Then, a 0.5% gadolinium (Gd) complex with carboxylic acid is loaded into the LAB-based LS by using the liquidliquid extraction method. In this paper, we will summarize all the characteristics of the Gd-loaded LAB-based LS for the Hanaro prototype detector.

Yeo, In Sung; Joo, Kyung Kwang; So, Sun Heang; Song, Sook Hyung; Kim, Hong Joo; So, Jung Ho; Park, Kang Soon; Ma, Kyung Ju; Jeon, Eun Ju; Kim, Jin Yu; Kim, Young Duk; Lee, Jason; Lee, Jeong-Yeon; Sun, Gwang-Min

2014-02-01

283

Inactivation of Heparin by Cationically Modified Chitosan  

PubMed Central

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

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

2014-01-01

284

Production of microparticles with gelatin and chitosan.  

PubMed

In the past few decades, the textile industry has significantly increased investment in research to develop functional fabrics, with a special focus on those aggregating values. Such fabrics can exploit microparticles inferior to 100 ?m, such as those made by complex coacervation in their creation. The antimicrobial properties of chitosan can be attributed to these microparticles. Developing particles with uniform structure and properties would facilitate the control for the eventual release of the core material. Thus, a complex coacervation between gelatin and chitosan was studied, and the optimal conditions were replicated in the encapsulation of limonene. Spherical particles formed had an average diameter (D3,2) of 30 ?m and were prepared with 89.7% efficiency. Cross-linking of these microparticles using glutaraldehyde and tripolyphosphate was carried out before spray drying. After drying, microparticles cross-linked with glutaraldehyde were oxidized and clustered and those that were cross-linked with tripolyphosphate resisted drying and presented a high yield. PMID:25458303

Prata, A S; Grosso, C R F

2015-02-13

285

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

PubMed Central

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

2013-01-01

286

Development of chitosan-based antimicrobial leather coatings.  

PubMed

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

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

2013-10-15

287

Emerging chitin and chitosan nanofibrous materials for biomedical applications  

NASA Astrophysics Data System (ADS)

Over the past several decades, we have witnessed significant progress in chitosan and chitin based nanostructured materials. The nanofibers from chitin and chitosan with appealing physical and biological features have attracted intense attention due to their excellent biological properties related to biodegradability, biocompatibility, antibacterial activity, low immunogenicity and wound healing capacity. Various methods, such as electrospinning, self-assembly, phase separation, mechanical treatment, printing, ultrasonication and chemical treatment were employed to prepare chitin and chitosan nanofibers. These nanofibrous materials have tremendous potential to be used as drug delivery systems, tissue engineering scaffolds, wound dressing materials, antimicrobial agents, and biosensors. This review article discusses the most recent progress in the preparation and application of chitin and chitosan based nanofibrous materials in biomedical fields.

Ding, Fuyuan; Deng, Hongbing; Du, Yumin; Shi, Xiaowen; Wang, Qun

2014-07-01

288

Development of a quaternized chitosan with enhanced antibacterial efficacy.  

PubMed

The antibacterial activity of a water-soluble chitosan derivative prepared by chemical modification to quaternary ammonium compound N,N,N-trimethylchitosan (TC) was investigated against four selected waterborne pathogens: Aeromonas hydrophila ATCC 35654, Yersinia enterocolitica ATCC 9610, Listeria monocytogenes ATCC 19111 and Escherichia coli O157:H7 ATCC 32150. An inactivation of 4 log CFU/ml of all waterborne pathogens was noted for the quaternized chitosan as compared with chitosan over a short contact time (30 min) and low dosage (4.5 ppm) at ambient temperature. A marked increase in glucose level, protein content and lactate dehydrogenase (LDH) activity was observed concurrently in the cell supernatant to be a major bactericidal mechanism. The results suggest that the TC derivative may be a promising commercial substitute for acid-soluble chitosan for rapid and effective disinfection of water. PMID:23981870

Khaira, Gurpreet Kaur; Kumariya, Rashmi; Chibber, Manmohan; Ghosh, Moushumi

2013-09-01

289

Microalgae harvesting by flotation using natural saponin and chitosan.  

PubMed

This study aims to investigate the harvesting of microalgae by dispersed air flotation (DiAF) using natural biosurfactant saponin as the collector and chitosan as the flocculant. Two types of microalgae, Chlorella vulgaris and Scenedesmus obliquus, were used in this study. It was observed that saponin was a good frother, but not an effective collector when used alone for flotation separation of algae. However, with the pre-flocculation of 5 mg/L of chitosan, separation efficiency of >93% microalgae cells was found at 20 mg/L of saponin. Removal efficiency of >54.4% and >73.0% was found for polysaccharide and protein, respectively at 20 mg/L of saponin and chitosan each. Experimental results show that DiAF using saponin and chitosan is effective for separation of microalgae, and algogenic organic matter (AOM). It can potentially be applied in the integrated microalgae-based biorefinery. PMID:24935003

Kurniawati, H Agnes; Ismadji, Suryadi; Liu, J C

2014-08-01

290

Emulsified Chitosan-plga Scaffolds for Tissue Engineering.  

E-print Network

??This study evaluated the formation of chitosan-50:50 poly-lactic-co-glycolic acid (PLGA) blend matrices using controlled rate freezing and lyophilization technique. An emulsion system was used in… (more)

Moshffeghian, Aliakbar

2005-01-01

291

Mechanism of Au(III) reduction by chitosan: Comprehensive study with (13)C and (1)H NMR analysis of chitosan degradation products.  

PubMed

The mechanism of Au(III) reduction by chitosan has been proposed on the basis of comprehensive study of kinetics of Au(III) reduction and chitosan chain degradation using UV-vis spectroscopy and viscosimetry, and identification of reaction products using colloid titration and (13)C, (1)H NMR spectroscopy. We have shown that formation of gold nanoparticles in H[AuCl4]/chitosan solutions starts with hydrolysis of chitosan catalyzed by Au(III). The products of chitosan hydrolysis rather than chitosan itself act as the main reducing species. According to (13)C and (1)H NMR spectroscopy data, chitosan/Au(0) composites contain chitosan with reduced molecular weight and acetylation degree, whereas water-soluble by-products consist of chitosan oligomers with higher acetylation degree, derivatives of glucosamine acids, and formate ion. Chitosan degradation has significantly contributed to the decrease of its efficiency as a gold nanoparticles stabilizer. The gold particle size increased from 6.9nm to 16.2nm, when Au(III)/chitosan molar ratio changed from 1:80 to 1:10. PMID:25498610

Pestov, Alexander; Nazirov, Alexander; Modin, Evgeny; Mironenko, Alexander; Bratskaya, Svetlana

2015-03-01

292

Effect of Chitosan on Salmonella Typhimurium in Broiler Chickens  

PubMed Central

Abstract Public concern with the incidence of antibiotic-resistant bacteria, particularly among foodborne pathogens such as Salmonella, has been challenging the poultry industry to find alternative means of control. The purposes of the present study were to evaluate in vitro and in vivo effects of chitosan on Salmonella enterica serovar Typhimurium (ST) infection in broiler chicks. For in vitro crop assay experiments, tubes containing feed, water, and ST were treated with either saline as a control or 0.2% chitosan. The entire assay was repeated in three trials. In two independent in vivo trials, 40 broiler chicks were assigned to an untreated control diet or dietary treatment with 0.2% chitosan for 7 days (20 broiler chicks/treatment). At day 4, chicks were challenged with 2×105 colony-forming units (CFU) ST/bird. In a third in vivo trial, 100 broiler chicks were assigned to untreated control diet or dietary treatment with 0.2% chitosan for 10 days (50 broiler chicks/treatment) to evaluate ST horizontal transmission. At day 3, 10 birds were challenged with 105 CFU ST/bird, and the remaining nonchallenged birds (n=40) were kept in the same floor pen. In all three in vitro trials, 0.2% chitosan significantly reduced total CFU of ST at 0.5 and 6?h postinoculation compared with control (p<0.05). In two in vivo trials, at 7 days, dietary 0.2% chitosan significantly reduced total CFU of recovered ST in the ceca in both experiments. Dietary 0.2% chitosan significantly reduced total ST CFU recovered in the ceca of horizontally challenged birds in the third in vivo trial. Chitosan at 0.2% significantly reduced the CFU of recovered ST in vitro and in vivo, proving to be an alternative tool to reduce crop, ceca, and consequently carcass ST contamination as well as decreasing the amount of ST shed to the environment. PMID:24237042

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

2014-01-01

293

Chitosan treatments affect growth and selected quality of sunflower sprouts.  

PubMed

The effects of chitosan molecular weights, solvent types, and concentrations of chitosan solution, and seed soaking times on growth and selected quality of sunflower sprouts were investigated. Among 5 chitosans tested (746, 444, 223, 67, and 28 kDa), 28 kDa chitosan exhibited the highest DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity both at 0.1% and 1.0% concentrations. Optimal conditions selected for cultivation of sunflower sprouts involved soaking seeds in 0.5% chitosan with 28 kDa (dissolved in 0.5% lactic acid) for 18 h. After cultivation for 6 d at 20 degrees C, sunflower seeds soaked in chitosan solution for 18 h under the optimal conditions yielded sprouts with 12.9% higher total weight and 16.0% higher germination rate, compared with those of seeds soaked in water for 18 h (control). Furthermore, the total amino acid content of the former sprouts (12098 mg/100 g) was slightly higher than that of the latter (12057 mg/100 g). Sprouting of sunflower seeds improved DPPH radical scavenging activity, probably due to the increased total phenolic, melatonin, and total isoflavone contents. Similarly, chitosan-treated sprouts exhibited slightly improved DPPH radical scavenging activity, probably due to slightly increased total phenolic and melatonin contents, and moderately increased total isoflavone content compared with those of the control. Chitosan treatment increased the total isoflavone content of sprouts by 11.8%, due mainly to the increased daidzein content, compared with that of the control. PMID:18211373

Cho, M H; No, H K; Prinyawiwatkul, W

2008-01-01

294

Preparation and characterization of magnetic nanoparticles with chitosan coating  

Microsoft Academic Search

Magnetic chitosan nanoparticles were prepared by the suspension cross-linking technique for use in the application of magnetic carrier technology. The Fe3O4 magnetic nanoparticles were synthesized by co-precipitation of FeCl2 and FeCl3 solution in base medium for using in the preparation of the magnetic chitosan. The morphological and magnetic properties of the magnetic nanoparticles were characterized by different techniques (TEM, XRD,

Doan Thi Kim Dung; Tran Hoang Hai; Le Hong Phuc; Bui Duc Long; Le Khanh Vinh; Phan Nha Truc

2009-01-01

295

Preparation of Magnetic Chitosan Nanoparticles for Diverse Biomedical Applications  

Microsoft Academic Search

Polymeric nanoparticles with magnetic properties can be potentially used in many fields such as biotechnology, separation\\u000a processes, optoelectronic, catalysts and\\/or sensors, medical diagnosis and therapy. In this respect, biopolymers give promising\\u000a 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

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

2008-01-01

296

Synthesis, characterization and properties of magnetic colloids supported on chitosan  

Microsoft Academic Search

This work proposes the synthesis, characterization and investigation of the stabilization capabilities of chitosan doped with\\u000a magnetic nanoparticles. Nanoparticles of Fe, Co, Co(II,III) oxide, Ni and Ni\\/Ag mixture in 2-propanol were synthesized by\\u000a chemical liquid deposition and the incorporation on the polymeric matrix was performed by solvated metal atom dispersion.\\u000a Colloids and nanoparticles supported on chitosan were characterized by ultraviolet,

Christian Cruzat Contreras; Octavio Peña; Manuel F. Meléndrez; Judith Díaz-Visurraga; Galo Cárdenas

2011-01-01

297

Effect of chitosan on Salmonella Typhimurium in broiler chickens.  

PubMed

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

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

2014-02-01

298

Synthesis and characterization of chitosan-graft-polycaprolactone copolymers  

Microsoft Academic Search

The graft copolymers of chitosan with polycaprolactone (PCL) were prepared through a protection-graft-deprotection route using phthaloylchitosan as intermediate. PCL macromonomers terminated with isocyanate groups reacted with hydroxyl groups of phthaloyl-protected chitosan regioselectively, and then phthaloyl groups were deprotected to give the free amino groups. The graft reaction was carried out in homogeneous system and yielded copolymers with high grafting content

Li Liu; Yu Li; Hao Liu; Yue’e Fang

2004-01-01

299

Mechanism of chitosan adsorption on silica from aqueous solutions.  

PubMed

We present a study of the adsorption of chitosan on silica. The adsorption behavior and the resulting layer properties are investigated by combining optical reflectometry and the quartz crystal microbalance. Exactly the same surfaces are used to measure the amount of adsorbed chitosan with both techniques, allowing the systematic combination of the respective experimental results. This experimental protocol makes it possible to accurately determine the thickness of the layers and their water content for chitosan adsorbed on silica from aqueous solutions of varying composition. In particular, we study the effect of pH in 10 mM NaCl, and we focus on the influence of electrolyte type and concentration for two representative pH conditions. Adsorbed layers are stable, and their properties are directly dependent on the behavior of chitosan in solution. In mildly acidic solutions, chitosan behaves like a weakly charged polyelectrolyte, whereby electrostatic attraction is the main driving force for adsorption. Under these conditions, chitosan forms rigid and thin adsorption monolayers with an average thickness of approximately 0.5 nm and a water content of roughly 60%. In neutral solutions, on the other hand, chitosan forms large aggregates, and thus adsorption layers are significantly thicker (?10 nm) as well as dissipative, resulting in a large maximum of adsorbed mass around the pK of chitosan. These films are also characterized by a substantial amount of water, up to 95% of their total mass. Our results imply the possibility to produce adsorption layers with tailored properties simply by adjusting the solution chemistry during adsorption. PMID:24725003

Tiraferri, Alberto; Maroni, Plinio; Rodríguez, Diana Caro; Borkovec, Michal

2014-05-01

300

In Situ Mineralization of Magnetite Nanoparticles in Chitosan Hydrogel  

NASA Astrophysics Data System (ADS)

Based on chelation effect between iron ions and amino groups of chitosan, in situ mineralization of magnetite nanoparticles in chitosan hydrogel under ambient conditions was proposed. The chelation effect between iron ions and amino groups in CS-Fe complex, which led to that chitosan hydrogel exerted a crucial control on the magnetite mineralization, was proved by X-ray photoelectron spectrum. The composition, morphology and size of the mineralized magnetite nanoparticles were characterized by X-ray diffraction, Raman spectroscopy, transmission electron microscopy and thermal gravity. The mineralized nanoparticles were nonstoichiometric magnetite with a unit formula of Fe2.85O4 and coated by a thin layer of chitosan. The mineralized magnetite nanoparticles with mean diameter of 13 nm dispersed in chitosan hydrogel uniformly. Magnetization measurement indicated that superparamagnetism behavior was exhibited. These magnetite nanoparticles mineralized in chitosan hydrogel have potential applications in the field of biotechnology. Moreover, this method can also be used to synthesize other kinds of inorganic nanoparticles, such as ZnO, Fe2O3 and hydroxyapatite.

Wang, Yongliang; Li, Baoqiang; Zhou, Yu; Jia, Dechang

2009-09-01

301

Chitosan Composites for Bone Tissue Engineering—An Overview  

PubMed Central

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

Venkatesan, Jayachandran; Kim, Se-Kwon

2010-01-01

302

Chitosan composites for bone tissue engineering--an overview.  

PubMed

Bone contains considerable amounts of minerals and proteins. Hydroxyapatite [Ca??(PO?)?(OH)?] 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 prostheses to treat the loss or failure of an organ or bone tissue. Chitosan has played a major role in bone tissue engineering over the last two decades, being a natural polymer obtained from chitin, which forms a major component of crustacean exoskeleton. In recent years, considerable attention has been given to chitosan composite materials and their applications in the field of bone tissue engineering due to its minimal foreign body reactions, an intrinsic antibacterial nature, biocompatibility, biodegradability, and the ability to be molded into various geometries and forms such as porous structures, suitable for cell ingrowth and osteoconduction. The composite of chitosan including hydroxyapatite is very popular because of the biodegradability and biocompatibility in nature. Recently, grafted chitosan natural polymer with carbon nanotubes has been incorporated to increase the mechanical strength of these composites. Chitosan composites are thus emerging as potential materials for artificial bone and bone regeneration in tissue engineering. Herein, the preparation, mechanical properties, chemical interactions and in vitro activity of chitosan composites for bone tissue engineering will be discussed. PMID:20948907

Venkatesan, Jayachandran; Kim, Se-Kwon

2010-01-01

303

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

2013-05-24

304

Colon specific chitosan microspheres for chronotherapy of chronic stable angina.  

PubMed

In the present work, chitosan microspheres with a mean diameter between 6.32 ?m and 9.44 ?m, were produced by emulsion cross-linking of chitosan, and tested for chronotherapy of chronic stable angina. Aiming at developing a suitable colon specific strategy, diltiazem hydrochloride (DTZ) was encapsulated in the microspheres, following Eudragit S-100 coating by solvent evaporation technique, exploiting the advantages of microbiological properties of chitosan and pH dependent solubility of Eudragit S-100. Different microsphere formulations were prepared varying the ratio DTZ:chitosan (1:2 to 1:10), stirring speed (1000-2000 rpm), and the concentration of emulsifier Span 80 (0.5-1.5% (w/v)). The effect of these variables on the particle size and encapsulation parameters (production yield (PY), loading capacity (LC), encapsulation efficiency (EE)) was evaluated to develop an optimized formulation. In vitro release study of non-coated chitosan microspheres in simulated gastrointestinal (GI) fluid exhibited a burst release pattern in the first hour, whereas Eudragit S-100 coating allowed producing systems of controlled release diffusion fitting to the Higuchi model, and thus suitable for colon-specific drug delivery. DSC analysis indicated that DTZ was dispersed within the microspheres matrix. Scanning electron microscopy revealed that the microspheres were spherical and had a smooth surface. Chitosan biodegradability was proven by the enhanced release rate of DTZ in presence of rat caecal contents. PMID:21194900

Jose, S; Prema, M T; Chacko, A J; Thomas, A Cinu; Souto, E B

2011-04-01

305

Chitosan as a sustainable organocatalyst: a concise overview.  

PubMed

Increased demand for more sustainable materials and chemical processes has tremendously advanced the use of polysaccharides, which are natural biopolymers, in domains such as adsorption, catalysis, and as an alternative chemical feedstock. Among these biopolymers, the use of chitosan, which is obtained by deacetylation of natural chitin, is on the increase due to the presence of amino groups on the polymer backbone that makes it a natural cationic polymer. The ability of chitosan-based materials to form open-network, macroporous, high-surface-area hydrogels with accessible basic surface sites has enabled their use not only as macrochelating ligands for active metal catalysts and as a support to disperse nanosized particles, but also as a direct organocatalyst. This review provides a concise overview of the use of native and modified chitosan, possessing different textural properties and chemical properties, as organocatalysts. Organocatalysis with chitosan is primarily focused on carbon-carbon bond-forming reactions, multicomponent heterocycle formation reactions, biodiesel production, and carbon dioxide fixation through [3+2] cycloaddition. Furthermore, the chiral, helical organization of the chitosan skeleton lends itself to use in enantioselective catalysis. Chitosan derivatives generally display reactivity similar to homogeneous bases, ionic liquids, and organic and inorganic salts. However, the introduction of cooperative acid-base interactions at active sites substantially enhances reactivity. These functional biopolymers can also be easily recovered and reused several times under solvent-free conditions. These accomplishments highlight the important role that natural biopolymers play in furthering more sustainable chemistry. PMID:25470553

El Kadib, Abdelkrim

2015-01-01

306

Horseradish peroxidase and chitosan: activation, immobilization and comparative results.  

PubMed

Recently, horseradish peroxidase (HRP) was immobilized on activated wool and we envisioned that the use of chitosan would be interesting instead of wool owing to its simple chemical structure, abundant nature and biodegradability. In this work, HRP was immobilized on chitosan crosslinked with cyanuric chloride. FT-IR spectroscopy and scanning electron microscopy were used to characterize immobilized HRP. The number of ten reuses of immobilized HRP has been detected. The pH was shifted from 5.5 for soluble HRP to 5.0 for immobilized enzyme. The soluble HRP had an optimum temperature of 30 °C, which was shifted to 35 °C for immobilized enzyme. The soluble HRP and immobilized HRP were thermal stable up to 35 and 45 °C, respectively. The apparent kinetic constant values (K(m)) of soluble HRP and chitosan-HRP were 35 mM and 40 mM for guaiacol and 2.73 mM and 5.7 mM for H2O2, respectively. Immobilization of HRP partially protected them from metal ions compared to soluble enzyme. The chitosan-HRP was remarkably more stable against urea, Triton X-100 and organic solvents. Chitosan-HRP exhibited large number of reuses and more resistance to harmful compounds compared with wool-HRP. On the basis of results obtained in the present study, chitosan-HRP could be employed in bioremediation application. PMID:23769933

Mohamed, Saleh A; Al-Malki, Abdulrahman L; Kumosani, Taha A; El-Shishtawy, Reda M

2013-09-01

307

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

308

Conductive macroporous composite chitosan-carbon nanotube scaffolds.  

PubMed

Multiwalled carbon nanotubes (MWCNTs) were used as doping material for three-dimensional chitosan scaffolds to develop a highly conductive, porous, and biocompatible composite material. The porous and interconnected structures were formed by the process of thermally induced phase separation followed by freeze-drying applied to an aqueous solution of 1 wt % chitosan acetic acid. The porosity was characterized to be 97% by both mercury intrusion porosimetry measurements and SEM image analysis. When MWCNTs were used as a filler to introduce conductive pathways throughout the chitosan skeleton, the solubilizing hydrophobic and hydrophilic properties of chitosan established stable polymer/MWCNT solutions that yielded a homogeneous distribution of nanotubes throughout the final composite matrix. A percolation theory threshold of approximately 2.5 wt % MWCNTs was determined by measurement of the conductivity as a function of chitosan/MWCNT ratios. The powder resistivity of completely compressed scaffolds also was measured and was found to be similar for all MWCNT concentrations (0.7-0.15 Omega cm powder resistivity for MWCNTs of 0.8-5 wt %) and almost five times lower than the 20 k Omega cm value found for pure chitosan scaffolds. PMID:18517231

Lau, Carolin; Cooney, Michael J; Atanassov, Plamen

2008-06-01

309

Oxidative Degradation of Chitosan to the Low Molecular Water-Soluble Chitosan over Peroxotungstate as Chemical Scissors  

PubMed Central

Low molecular water-soluble chitosan was prepared by the depolymerization of chitosan in the presence of a series of catalysts with active W(O2) sites. Both the peroxo species [W2O3(O2)4]2- and {PO4[WO(O2)2]4}3- showed high efficiency in the degradation of chitosan, indicating that the degradation mechanism did not follow the radical mechanism. That means •OH is not the active species, which has been proven by the fluorescence spectra. H2O2 acted as an oxidant to regenerate the active W(O2) sites in the depolymerization of chitosan. The developed catalyst (TBA)3{PO4[WO(O2)2]4} is recoverable. PMID:24971631

Ma, Zhanwei; Wang, Wenyan; Wu, Ying; He, Yiming; Wu, Tinghua

2014-01-01

310

Preparation, characterization and in vitro evaluation of nanostructured chitosan/apatite and chitosan/Si-doped apatite composites  

E-print Network

Chitosan/apatite composites are attracting great attention as biomaterials for bone repair and regeneration procedures. The reason is their unique set of properties: bioactivity and osteoconductivity provided by apatite and resorbability supplied...

Solis, Yaimara; Davidenko, Natalia; Carrodeguas, Raul G; Cruz, Jeny; Hernandez, Andy; Tomas, Miriela; Cameron, Ruth Elizabeth; Peniche, Carlos

2013-01-01

311

Fluorescent cadmium telluride quantum dots embedded chitosan nanoparticles: a stable, biocompatible preparation for bio-imaging.  

PubMed

Fluorescent cadmium telluride quantum dots (CdTe QDs) are an optically attractive option for bioimaging, but are known to display high cytotoxicity. Nanoparticles synthesized from chitosan, a natural biopolymer of ? 1-4 linked glucosamine, display good biocompatibility and cellular uptake. A facile, green synthetic strategy has been developed to embed green fluorescent cadmium telluride quantum dots (CdTe QDs) in biocompatible CNPs to obtain a safer preparation than 'as is' QDs. High-resolution transmission electron microscopy showed the crystal lattice corresponding to CdTe QDs embedded in CNPs while thermogravimetry confirmed their polymeric composition. Electrostatic interactions between thiol-capped QDs (4 nm, -57 mV) and CNPs (~300 nm, +38 mV) generated CdTe QDs-embedded CNPs that were stable up to three months. Further, viability of NIH3T3 mouse fibroblast cells in vitro increased in presence of QDs-embedded CNPs as compared to bare QDs. At the highest concentration (10 ?g/ml), the former shows 34 and 39% increase in viability at 24 and 48 h, respectively, as compared to the latter. This shows that chitosan nanoparticles do not release the QDs up to 48 h and do not cause extended toxicity. Furthermore, hydrolytic enzymes such as lysozyme and chitinase did not degrade chitosan nanoparticles. Moreover, QDs-embedded CNPs show enhanced internalization in NIH3T3 cells as compared to bare QDs. This method offers ease of synthesis and handling of stable, luminescent, biocompatible CdTe QDs-embedded CNPs with a favorable toxicity profile and better cellular uptake with potential for bioimaging and targeted detection of cellular components. PMID:25410797

Ghormade, Vandana; Gholap, Haribhau; Kale, Sonia; Kulkarni, Vaishnavi; Bhat, Suresh; Paknikar, Kishore

2015-01-01

312

COMPARISON OF METHODS TO EVALUATE CHITOSAN AS AN ANTIMICROBIAL AGAINST LISTERIA SPP. CULTURES.  

E-print Network

?? The antimicrobial properties of a chitosan-coated vacuum-packaged pouch were tested against Listeria monocytogenes (LM) inoculated on frankfurters. A 1.5% chitosan solution was successfully coated… (more)

Hartley, Scott

2013-01-01

313

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

314

Nutraceuticals in Lipid-Lowering Treatment: A Narrative Review on the Role of Chitosan.  

PubMed

Lipid-lowering drugs may cause adverse effects and, although lipid targets may be achieved, a substantial residual cardiovascular (CV) risk remains. Treatment with agents mimicking proteins present in the body, such as incretin-based therapies, provided promising results. However, in order to improve lipids and CV risk, lifestyle measures remain important. Some researchers focused on nutraceuticals that may beneficially affect metabolic parameters and minimize CV risk. Chitosan, a dietary fiber, can regulate lipids with benefit on anthropometric parameters. The beneficial properties of dietary supplements (such as green tea extract, prebiotics, plant sterols, and stanols) on plasma lipids, lipoproteins, blood pressure, glucose, and insulin levels and their anti-inflammatory and anti-oxidant effects are documented. However, larger, prospective clinical trials are required to confirm such benefits. Such treatments may be recommended when lipid-lowering drugs are neither indicated nor tolerated as well as in order to achieve therapeutic targets and/or overcome residual CV risk. PMID:25037700

Patti, Angelo Maria; Katsiki, Niki; Nikolic, Dragana; Al-Rasadi, Khalid; Rizzo, Manfredi

2014-07-18

315

Evaluation of Cross-Linked Chitosan as Filler on Mechanical Properties of Chitosan-Based Bio-Composites  

Microsoft Academic Search

The cross-linked chitosan (XCs) was applied as a filler for chitosan (Cs) matrix. The composites film was prepared by solution casting at 0 to 12 wt\\/v% content of XCs filler and characterized under tensile analysis. The tensile strength (TS) and Young Modulus (YM) increased lineraly with the content of XCs filler (2 to 8 wt\\/v%). Contrarily, tensile strain (EB) and toughness (K)

Nurhidayatullaili Muhd Julkapli; Zulkifli Ahmad

2012-01-01

316

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

317

Characterization of Chitosan-poly (Ethylene Oxide) Blends as Haemodialysis Membrane  

Microsoft Academic Search

Blend membranes of chitosan and poly (ethylene oxide) with different molecular weights of 100,000 and 600,000 were prepared by the solution cast technique. The chitosan-PEO blends membranes were produced to study their water adsorptions capacity and characteristics for haemodialysis membrane application. An increase in the water adsorption capacity of chitosan-PEO blend membranes compared to the pure chitosan was due to

N. F. Mohd Nasir; N. Mohd Zain; M. G. Raha; N. A. Kadri

318

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

319

Magnetic chitosan\\/iron (II, III) oxide nanoparticles prepared by spray-drying  

Microsoft Academic Search

Chitosan\\/iron (II, III) oxide nanoparticles with various ratios of chitosan\\/iron (CS1\\/Fe4, CS2\\/Fe4 and CS3\\/Fe4) were prepared by a spray-drying method. Atomic absorption spectrometry (AAS), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) spectrometry data confirm that magnetic crystalline Fe3O4 interacts with chitosan and distributes in the chitosan matrix. Field emission scanning electron microscopy (FESEM) micrographs indicate that nanoparticles so

Hsin-Yi Huang; Yeong-Tarng Shieh; Chao-Ming Shih; Yawo-Kuo Twu

2010-01-01

320

Synthesis, characterization and biocompatibility studies on chitosan- graft-poly(EGDMA)  

Microsoft Academic Search

Poly(ethylene glycol dimethacrylate), poly(EGDMA), was grafted onto chitosan by using a redox initiation system. Chitosan-graft-poly(EGDMA) products were characterized by DSC, TGA, FTIR and XRD techniques. Chitosan-graft-poly(EGDMA) was found to be enzymatically degradable in aqueous solutions of lysozyme, lipase and a mixture of ?-amylase and protease. The biocompatibility of chitosan-graft-poly(EGDMA) with 871% grafting yield was investigated by studying its cytotoxicity, sensitization,

Terin Adali; Elvan Yilmaz

2009-01-01

321

Chitosan-graft-spermine as a gene carrier in vitro and in vivo  

Microsoft Academic Search

Chitosan has been proposed as a non-viral gene carrier because of its biodegradable and biocompatible cationic polymeric properties. However, the transfection efficiency of chitosan-DNA complexes is still too low for clinical trials. To improve transfection efficiency, we prepared a chitosan-graft-spermine (CHI-g-SPE) copolymer by an imine reaction between periodate-oxidized chitosan and spermine. The CHI-g-SPE copolymer was complexed with plasmid DNA in

Hu-Lin Jiang; Hwang-Tae Lim; You-Kyoung Kim; Rohidas Arote; Ji-Young Shin; Jung-Taek Kwon; Ji-Eun Kim; Ji-Hye Kim; Duyeol Kim; Chanhee Chae; Jae-Woon Nah; Yun-Jaie Choi; Chong-Su Cho; Myung-Haing Cho

2011-01-01

322

Microwave synthesized chitosan- graft-poly(methylmethacrylate): An efficient Zn 2+ ion binder  

Microsoft Academic Search

Microwave promoted grafting of methylmethacrylate on to the chitosan has been optimized. Chitosan-graft-poly(methylmethacrylate) (Ch-g-PMMA) could be synthesized with 160% grafting using 80% MW power in 2min at (MMA) 0.17M, (Chitosan) 0.1g\\/25ml. While for the same concentration of the methylmethacrylate and the chitosan, 105% grafting was observed when K2S2O8\\/ascorbic acid redox initiator used in presence of Ag+ (catalyst) and atmospheric oxygen

Vandana Singh; Devendra Narayan Tripathi; Ashutosh Tiwari; Rashmi Sanghi

2006-01-01

323

Effects of molecular weight and deacetylation degree of chitin\\/chitosan on wound healing  

Microsoft Academic Search

We studied the effects of chitin\\/chitosan on wound healing with reference to chemical properties using a linear incisional wound model in rats. Wound break strength of the chitosan group (D-glucosamine (GlcN), chito-oligosaccharide (COS), chitosan) was higher than the chitin group (N-acetyl-D-glucosamine (GlcNAc), chiti-oligosaccharide (NACOS), chitin). Collagenase activity was also higher in the chitosan group than the chitin group. There was

Tatsuya Minagawa; Yasuhiko Okamura; Yoshihiro Shigemasa; Saburo Minami; Yoshiharu Okamoto

2007-01-01

324

Effect of complexation conditions on xanthan–chitosan polyelectrolyte complex gels  

Microsoft Academic Search

Polyelectrolyte hydrogels formed by xanthan gum and chitosan can be used for encapsulation and controlled release of food ingredients, cells, enzymes, and therapeutic agents. In this study, xanthan–chitosan microcapsules were formed by complex coacervation. The effects of initial polymer concentration and chitosan solution pH on the crosslinking density of xanthan–chitosan network were investigated by swelling studies and modulated differential scanning

Sanem Argin-Soysal; Peter Kofinas; Y. Martin Lo

2009-01-01

325

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

326

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

327

Efficient gene silencing in lungs and liver using imidazole-modified chitosan as a nanocarrier for small interfering RNA.  

PubMed

Despite high specificity and potency, small interfering RNA (siRNA)-based therapeutics have been limited by their poor biostability and intracellular penetration. Thus, effective nanocarriers that can protect and efficiently deliver siRNA to target cells in vivo are needed. Here we report on the efficiency of imidazole-modified chitosan (chitosan-imidazole-4-acetic acid [IAA])-siRNA nanoparticles to mediate gene silencing after administration via either intravenous (i.v.) or intranasal (i.n.) routes. Poly(ethylene glycol) (PEG)ylated nanoparticles for i.v. delivery demonstrated significant knockdown of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) enzyme in both lung and liver at as low as 1 mg/kg siRNA dose. In addition, the efficient, dose-dependent silencing of apolipoprotein B in the liver was also shown. For i.n. delivery, significant silencing of GAPDH protein expression was seen in the lungs with only 0.5 mg/kg/day siRNA delivered over 3 consecutive days. In summary, imidazole-modified chitosan-IAA nanoparticles are potentially effective carriers for siRNA delivery. PMID:20565242

Ghosn, Bilal; Singh, Ankur; Li, Mu; Vlassov, Alexander V; Burnett, Chris; Puri, Nitin; Roy, Krishnendu

2010-06-01

328

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

PubMed

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

Kubiak, Tomasz

2014-01-01

329

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

PubMed Central

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

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

2013-01-01

330

Identification of yeast genes that confer resistance to chitosan oligosaccharide (COS) using chemogenomics  

PubMed Central

Background Chitosan oligosaccharide (COS), a deacetylated derivative of chitin, is an abundant, and renewable natural polymer. COS has higher antimicrobial properties than chitosan and is presumed to act by disrupting/permeabilizing the cell membranes of bacteria, yeast and fungi. COS is relatively non-toxic to mammals. By identifying the molecular and genetic targets of COS, we hope to gain a better understanding of the antifungal mode of action of COS. Results Three different chemogenomic fitness assays, haploinsufficiency (HIP), homozygous deletion (HOP), and multicopy suppression (MSP) profiling were combined with a transcriptomic analysis to gain insight in to the mode of action and mechanisms of resistance to chitosan oligosaccharides. The fitness assays identified 39 yeast deletion strains sensitive to COS and 21 suppressors of COS sensitivity. The genes identified are involved in processes such as RNA biology (transcription, translation and regulatory mechanisms), membrane functions (e.g. signalling, transport and targeting), membrane structural components, cell division, and proteasome processes. The transcriptomes of control wild type and 5 suppressor strains overexpressing ARL1, BCK2, ERG24, MSG5, or RBA50, were analyzed in the presence and absence of COS. Some of the up-regulated transcripts in the suppressor overexpressing strains exposed to COS included genes involved in transcription, cell cycle, stress response and the Ras signal transduction pathway. Down-regulated transcripts included those encoding protein folding components and respiratory chain proteins. The COS-induced transcriptional response is distinct from previously described environmental stress responses (i.e. thermal, salt, osmotic and oxidative stress) and pre-treatment with these well characterized environmental stressors provided little or any resistance to COS. Conclusions Overexpression of the ARL1 gene, a member of the Ras superfamily that regulates membrane trafficking, provides protection against COS-induced cell membrane permeability and damage. We found that the ARL1 COS-resistant over-expression strain was as sensitive to Amphotericin B, Fluconazole and Terbinafine as the wild type cells and that when COS and Fluconazole are used in combination they act in a synergistic fashion. The gene targets of COS identified in this study indicate that COS’s mechanism of action is different from other commonly studied fungicides that target membranes, suggesting that COS may be an effective fungicide for drug-resistant fungal pathogens. PMID:22727066

2012-01-01

331

Development of a chitosan-based wound dressing with improved hemostatic and antimicrobial properties  

Microsoft Academic Search

Hemorrhage remains a leading cause of early death after trauma, and infectious complications in combat wounds continue to challenge caregivers. Although chitosan dressings have been developed to address these problems, they are not always effective in controlling bleeding or killing bacteria. We aimed to refine the chitosan dressing by incorporating a procoagulant (polyphosphate) and an antimicrobial (silver). Chitosan containing different

Shin-Yeu Ong; Jian Wu; Shabbir M. Moochhala; Mui-Hong Tan; Jia Lu

2008-01-01

332

In vivo evaluation of thiolated chitosan tablets for oral insulin delivery.  

PubMed

Chitosan-6-mercaptonicotinic acid (chitosan-6-MNA) is a thiolated chitosan with strong mucoadhesive properties and a pH-independent reactivity. This study aimed to evaluate the in vivo potential for the oral delivery of insulin. The comparison of the nonconjugated chitosan and chitosan-6-MNA was performed on several studies such as mucoadhesion, release, and in vivo studies. Thiolated chitosan formulations were both about 80-fold more mucoadhesive compared with unmodified ones. The thiolated chitosan tablets showed a sustained release for 5 h for the polymer of 20 kDa and 8 h for the polymer of 400 kDa. Human insulin was quantified in rats' plasma by means of ELISA specific for human insulin with no cross-reactivity with the endogenous insulin. In vivo results showed thiolation having a tremendous impact on the absorption of insulin. The absolute bioavailabilities were 0.73% for chitosan-6-MNA of 20 kDa and 0.62% for chitosan-6-MNA 400 kDa. The areas under the concentration-time curves (AUC) of chitosan-6-MNA formulations compared with unmodified chitosan were 4.8-fold improved for the polymer of 20 kDa and 21.02-fold improved for the polymer of 400 kDa. The improvement in the AUC with regard to the most promising aliphatic thiomer was up to 6.8-fold. Therefore, chitosan-6-MNA represents a promising excipient for the oral delivery of insulin. PMID:25139279

Millotti, Gioconda; Laffleur, Flavia; Perera, Glen; Vigl, Claudia; Pickl, Karin; Sinner, Frank; Bernkop-Schnürch, Andreas

2014-10-01

333

URANIUM REMOVAL BY CHITOSAN IMPREGNATED WITH MAGNETITE NANOPARTICLES: ADSORPTION AND DESORPTION  

Microsoft Academic Search

A magnetic biosorbent composed of nanoparticles of magnetite covered with chitosan, denominated magnetic chitosan, was prepared. The magnetic chitosan has showed a magnetic response of intense attraction in the presence of a magnetic field without however to become magnetic, a typical behavior of superparamagnetic material. Its adsorption performance was evaluated by the adsorption isotherm models of Langmuir and Freundlich for

Luiz Cláudio; Barbosa Stop; Mitiko Yamaura

334

Surface characterization and platelet compatibility evaluation of surface-sulfonated chitosan membrane  

Microsoft Academic Search

The effect of various sulfonated derivatives of chitosan on platelet activation and blood coagulation was examined. The surface properties of artificial biomaterials have been thought as the key factors which mediate the interactions between the biological environment and biomaterial itself. In this study, the sulfonation was directly performed on the chitosan membrane surface. The chitosan membrane was surface-sulfonated by reactions

Chia-Wen Lin; Jui-Che Lin

2001-01-01

335

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

Microsoft Academic Search

Weak binding of chitosan on the wool constitutes the main problem in its application. In this paper, the surface modification of wool fabric using anhydrides to graft the chitosan was studied. Weight gain, antibacterial and antifelting properties of the chitosan grafted-acylated wool fabric were investigated. Wool fabrics were acylated with two anhydrides, succinic anhydride (SA) and phthalic anhydride (PA), using

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

2010-01-01

336

Synthesis and characterization of a novel amphiphilic chitosan–polylactide graft copolymer  

Microsoft Academic Search

Water soluble chitosan (CS) derivatives containing polylactide unit were synthesized by reacting dl-lactide (DLLA) with chitosan in dimethyl sulfoxide solution in the presence of triethylamine. The chemical structure and physical properties of chitosan derivatives were characterized by FTIR, 1HNMR, TGA and XRD. Formation and characteristics of polymeric micelles of graft copolymers were studied by fluorescence spectroscopy and dynamic light scattering

Yan Wu; Yongli Zheng; Wuli Yang; Changchun Wang; Jianhua Hu; Shoukuan Fu

2005-01-01

337

Video-Gait Analysis of Functional Recovery of Nerve Repaired with Chitosan Nerve Guides  

E-print Network

Video-Gait Analysis of Functional Recovery of Nerve Repaired with Chitosan Nerve Guides MINAL PATEL assessment of functional sciatic nerve recovery treated with chitosan nerve guides. We used video to functional nerve recovery. The chitosan group showed increased functional improvement compared to the control

VandeVord, Pamela

338

Influence of Drying Techniques on the Characteristics of Chitosan and the Quality of Biopolymer Films  

Microsoft Academic Search

In this work, spouted bed and tray-drying techniques were employed at different drying air temperatures to produce dried chitosan, and the chitosan powder was used to produce biofilms. The products obtained from each drying technique were compared in relation to quality aspects (molecular weight, lightness, and hue angle). The results found for chitosan in spouted bed drying (90°C) showed lower

Guilherme Luiz Dotto; Vanderlei Constantino de Souza; Jaqueline Motta de Moura; Catarina Motta de Moura; Luiz Antonio de Almeida Pinto

2011-01-01

339

Complete Physicochemical Characterization of DNA/Chitosan Complexes by Multiple Detection  

E-print Network

Complete Physicochemical Characterization of DNA/Chitosan Complexes by Multiple Detection Using dispersions of DNA/ rhodamine B labeled chitosan (Ch-rho) complexes frequently used as gene delivery vectors the transfection efficiency of DNA/chitosan complexes, including the DNA concentration at mixing (82-164 µg

Buschmann, Michael

340

Chitosans for delivery of nucleic acids Michael D. Buschmann, Abderrazzak Merzouki, Marc Lavertu, Marc  

E-print Network

Ã?Ã? Ã? Ã?Ã?Ã? Ã? Ã?Ã? Chitosans for delivery of nucleic acids Michael D. Buschmann, Abderrazzak Merzouki Thibault, Myriam Jean, Vincent Darras, Chitosans for delivery of nucleic acids, Advanced Drug Delivery MANUSCRIPT ACCEPTED MANUSCRIPT 1 Title: Chitosans for Delivery of Nucleic Acids Michael D. Buschmann

Buschmann, Michael

341

GDNF blended chitosan nerve guides: An in vivo study Minal Patel,1,2  

E-print Network

GDNF blended chitosan nerve guides: An in vivo study Minal Patel,1,2 Li Mao,2 Bin Wu,2 Pamela Vande.a.32072 Abstract: Chitosan nerve guides are currently being uti- lized to repair damaged or injured, researchers are focusing on blending dif- ferent proteins or molecules with chitosan to facilitate nerve

VandeVord, Pamela

342

Formulation pH Modulates the Interaction of Insulin with Chitosan Nanoparticles  

E-print Network

Formulation pH Modulates the Interaction of Insulin with Chitosan Nanoparticles ZENGSHUAN MA,1 HOCK studies on chitosan-insulin nanoparticles have reported diverse encapsulation efficiency and insulin the efficiency and mechanism of asso- ciation of insulin with chitosan nanoparticles in the pH range of 2.3 to 6

Yeoh, Hock Hin

343

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

E-print Network

Biomaterials 27 (2006) 4815­4824 High efficiency gene transfer using chitosan/DNA nanoparticles 3A7 Received 28 February 2006; accepted 18 April 2006 Available online 24 May 2006 Abstract Chitosan the influence of these parameters on gene transfer, we produced chitosans with different DDAs (98%, 92%, 80

Buschmann, Michael

344

Monolithic gelation of chitosan solutions via enzymatic hydrolysis of urea A. Chenite a,  

E-print Network

Monolithic gelation of chitosan solutions via enzymatic hydrolysis of urea A. Chenite a, *, S. Gori process for the formation of physical hydrogels of chitosan from injectable aqueous solutions is investigated. Uniform neutralization of chitosan solutions with ammonia generated in situ from enzymatic

Buschmann, Michael

345

A replica molding technique for producing fibrous chitosan scaffolds for cartilage engineering; {  

E-print Network

A replica molding technique for producing fibrous chitosan scaffolds for cartilage engineering in the micron regime from the naturally derived biopolymer chitosan. The process involves filling an array of microchannels recessed into a mold surface with a solution bearing chitosan, inducing a pH-dependent coagulation

Cunningham, Brian

346

Rheology of highly swollen chitosan/polyacrylate hydrogels H. Jianga,b  

E-print Network

Rheology of highly swollen chitosan/polyacrylate hydrogels H. Jianga,b , W. Sua,c , P.T. Mathera Abstract Recently we reported on chitosan hydrogel systems having excellent laser damage resistance Ltd. All rights reserved. Keywords: Hydrogel; Chitosan; Rheology 1. Introduction The rapid increase

Mather, Patrick T.

347

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

348

Measurement of x-ray attenuation coefficients of aqueous solutions of indocyanine green and glycated chitosan  

E-print Network

and glycated chitosan Fang Xu and Hong Liua) Department of Radiology and Biomedical Engineering, University of a light absorbing dye, indocyanine green, and an immunoadjuvant, glycated chitosan. In the treatment results show that glycated chitosan has a higher attenuation coefficient compared to indocyanine green

Jiang, Hangyi

349

Chitosan: an integrative biomaterial for lab-on-a-chip devices S. T. Koev,a  

E-print Network

Chitosan: an integrative biomaterial for lab-on-a-chip devices S. T. Koev,a P. H. Dykstra,a X. Luo August 2010 DOI: 10.1039/c0lc00047g Chitosan is a naturally derived polymer with applications properties and film forming ability, chitosan serves as a matrix for the assembly of biomolecules, cells

Rubloff, Gary W.

350

Spatial resolution in chitosan-based programmable biomolecular scaffolds Susan L. Buckhout-Whiteab  

E-print Network

Spatial resolution in chitosan-based programmable biomolecular scaffolds Susan L. Buckhout Article on the web 13th July 2009 DOI: 10.1039/b820356c The polysaccharide chitosan is a versatile dimensions, we have investigated the spatial resolution which the chitosan electrodeposition process can

Rubloff, Gary W.

351

In situ quantitative visualization and characterization of chitosan electrodeposition with paired sidewall electrodes  

E-print Network

In situ quantitative visualization and characterization of chitosan electrodeposition with paired the first in situ quantitative visualization and characterization of electro-induced chitosan hydrogelH and the time-dependent growth profiles of the chitosan hydrogel were directly visualized, analyzed

Rubloff, Gary W.

352

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

353

Chitosan microspheres prepared by spray drying.  

PubMed

Non-crosslinked and crosslinked chitosan microspheres were prepared by a spray drying method. The microspheres so prepared had a good sphericity and a smooth but distorted surface morphology. They were positively charged. The particle size ranged from 2 to 10 micron. The size and seta potential of the particles were influenced by the crosslinking level. With decreasing amount of crosslinking agent (either glutaraldehyde or formaldehyde), both particle size and zeta potential were increased. Preparation conditions also had some influence on the particle size. DSC studies revealed that the H2 antagonist drug cimetidine, as well as famotidine was molecularly dispersed inside the microspheres, in the form of a solid solution. The release of model drugs (cimetidine, famotidine and nizatidine) from these microspheres was fast, and accompanied by a burst effect. PMID:10502613

He, P; Davis, S S; Illum, L

1999-09-30

354

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...

355

MASKER MASKER TARGET TARGET TARGET  

E-print Network

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

Ives, D. Timothy

356

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

PubMed

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

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

2014-07-29

357

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. PMID:24106677

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

2013-01-01

358

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

PubMed Central

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

Liu, Karen C.; Yeo, Yoon

2013-01-01

359

Influence of chitosan glutamate on the in vivo intranasal absorption of rokitamycin from microspheres.  

PubMed

Intranasal delivery is an alternative method to target therapeutics to the central nervous system. In the present study, chitosan glutamate (CG)-based mucoadhesive microspheres containing rokitamycin (RK) were prepared by spray-drying and in vitro characterization. Moreover, the influence of CG on RK absorption in bloodstream and cerebrospinal fluid (CSF) was evaluated after nasal administration to rats. The in vivo results were compared with those obtained after nasal administration of chitosan (CH)-based microparticles containing RK and after intravenous (IV) administration of the free drug. The in vitro results indicate that the concentrations of feed solution or kind of CH influence the RK entrapment and size of microspheres. All formulations increase the solubility of this poorly water-soluble drug, but CG is more able to increase the in vitro dissolution rate of RK than CH. CG microspheres absorb water quickly and then dissolve, whereas CH particles need more volume of water for swelling and gelling. In vivo studies showed that, after IV administration, RK is not able to cross the blood-brain barrier and to reach the CSF from the bloodstream. On the contrary, drug goes to the CSF and the bloodstream only after nasal administration of CG microparticles. PMID:24081472

Gavini, Elisabetta; Rassu, Giovanna; Ferraro, Luca; Generosi, Amanda; Rau, Julietta V; Brunetti, Antonio; Giunchedi, Paolo; Dalpiaz, Alessandro

2011-04-01

360

Electrophoretic fabrication of chitosan-zirconium-oxide nanobiocomposite platform for nucleic acid detection.  

PubMed

The present work describes electrophoretic fabrication of nanostructured chitosan-zirconium-oxide composite (CHIT-NanoZrO(2)) film (180 nm) onto indium-tin-oxide (ITO)-coated glass plate. This nanobiocomposite film has been explored as immobilization platform for probe DNA specific to M. Tuberculosis as model biomolecule to investigate its sensing characteristics. It is revealed that pH-responsive behavior of CHIT and its cationic skeleton is responsible for the movement of CHIT-NanoZrO(2) colloids toward cathode during electrophoretic deposition. The FT-IR, SEM, TEM, and EDX techniques have been employed for the structural, morphological, and composition analysis of the fabricated electrodes. The morphological studies clearly reveal uniform inter-linking and dispersion of hexagonal nanograins of ZrO(2) (30-50 nm) into the chitosan matrix, resulting in homogeneous nanobiocomposite formation. Electrochemical response measurements of DNA/CHIT-NanoZrO(2)/ITO bioelectrode, carried out using cyclic voltammetry and differential pulse voltammetry, reveal that this bioelectrode can specifically detect complementary target DNA up to 0.00078 ?M with sensitivity of 6.38 × 10(-6) A?M(-1). PMID:21218766

Das, Maumita; Dhand, Chetna; Sumana, Gajjala; Srivastava, A K; Nagarajan, R; Nain, Lata; Iwamoto, M; Manaka, Takaaki; Malhotra, B D

2011-03-14

361

Changes in blood aggregation with differences in molecular weight and degree of deacetylation of chitosan.  

PubMed

Because the molecular weight (Mw) and degree of deacetylation (DDA) of chitosan can vary depending on the purification method, the identification of appropriate chitosan structures is important for developing more effective hemostatic agents. In this study, the influence of varying Mw and DDA of chitosan on blood aggregation was characterized by 10 types of chitosan with different Mw and DDA, including oligomers. The highest aggregation of whole blood, washed erythrocytes and platelets in platelet-rich plasma (PRP) were observed in chitosan with Mw of 8.6?kDa or more and with DDA of 75 to 88%. However, chitosan with too high Mw (247?kDa) inhibited the aggregation of whole blood, washed erythrocytes and PRP at high chitosan concentration. At certain concentrations, chitosan with 75-85% DDA and 50-190?kDa and chitosan with 87.6% DDA and 247?kDa both aggregated proteins in PRP. Chitosan oligomer did not affect blood aggregation. The results suggested that the aggregation by chitosan depended on the interaction of positively charged chitosan with negatively charged erythrocytes, platelets and plasma protein. It seemed that a suitable balance of positive charge in chitosan and negative charge in hemocytes and some kinds of proteins was important. To develop a hemostatic with effective blood aggregation, the chitosan should not be limited to a single Mw and a single DDA but may be a mixed chitosan with wide range of Mw (8.6-247?kDa) and DDA of 75 to 88%. PMID:25611127

Hattori, Hidemi; Ishihara, Masayuki

2015-01-01

362

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

Microsoft Academic Search

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

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

2011-01-01

363

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

364

Adsorption of anionic dyes on chitosan grafted poly(alkyl methacrylate)s  

Microsoft Academic Search

Chitosan grafted poly(alkyl methacrylate)s (namely chitosan grafted poly(methyl methacrylate) (ChgPMMA), chitosan grafted poly(ethyl methacrylate) (ChgPEMA), chitosan grafted poly(butyl methacrylate) (ChgPBMA) and chitosan grafted poly(hexyl methacrylate) (ChgPHMA)) were synthesized and characterized by using FT-IR and 13C NMR techniques. The adsorption batch experiments on these grafted copolymers were conducted by using an anionic sulfonated dye, Orange-G. A pseudo-second-order kinetic model was used

Vinod Kumar Konaganti; Ramanjaneyulu Kota; Satish Patil; Giridhar Madras

2010-01-01

365

Effect of chitosan-based edible coating on preservation of white shrimp during partially frozen storage.  

PubMed

Chitosan and chitooligosaccharides are preservatives with proven antibacterial activity, while glutathione has antioxidant activity. This study investigated the effects of chitosan coating combined with chitooligosaccharides and glutathione (0.8% glutathione+1% chitooligosaccharides+1% chitosan) on preservation of white shrimp (Penaeus vannamei) during partially frozen storage. Chitosan-based coating treatments effectively inhibited bacterial growth, reduced total volatile basic nitrogen and malondialdehyde, and basically maintained the sensory properties of white shrimp (P. vannamei) during partially frozen storage. Therefore, chitosan-based edible coating combined with chitooligosaccharides and glutathione could be a promising antimicrobial and oxidant method to prevent metamorphism of white shrimp with extended shelf life. PMID:24491494

Wu, Shengjun

2014-04-01

366

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

367

Correlation of chitosan's rheological properties to its ability to electrospin  

NASA Astrophysics Data System (ADS)

Chitosan, derived from chitin found in the exoskeleton of crustaceans, has been investigated extensively for use in biomedical applications ranging from drug delivery to scaffolds for tissue engineering. Therefore, forming nanofibers of this linear polysaccharide is desirable for use in such applications, because the nanofibers can be tailored to mimic the size and porosity of the extracellular matrix. Electrostatic spinning (electrospinning) is a convenient method to produce nonwoven mats of nanofibers. The ability of the solutions to successfully electospin is closely correlated with the rheological properties of the solutions. Chitosan is challenging to electrospin due to its relatively high viscosity at modest concentrations. Solutions of chitosan blended with poly(ethylene oxide) (PEO) have been electrospun successfully with freshly prepared solutions. If the blended solutions are stored, they do not readily electrospin. Moreover, chitosan/PEO blend solutions show a drastic decrease in zero shear rate viscosity over time, which can be attributed to phase separation. The challenges associated with electrospinning charged biopolymers (chitosan is cationic) will be discussed in terms of their rheological properties. Successes and failures will be highlighted and compared results for readily electrospun neutral polymers.

Krause, Wendy E.; Queen, Hailey A.; Klossner, Rebecca R.; Coughlin, Andrew J.

2007-03-01

368

Chitosan microneedle patches for sustained transdermal delivery of macromolecules.  

PubMed

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

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

2012-12-10

369

In vitro damage of Candida albicans biofilms by chitosan  

PubMed Central

With the increasing usage of indwelling medical devices in clinical practice, the frequency of fungal infections has increased, such as that of Candida albicans (C. albicans). Biofilms, a protected niche for microorganisms, are resistant to a range of current antifungal agents. Chitosan is a polyatomic biopolymer with advantageous biocompatibility, biodegradation, nontoxicity and antibacterial properties. To investigate the inhibitory effect of chitosan on biofilms formed by C. albicans, cell viability, 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-caboxanilide reduction, and morphological assays, including fluorescence microscopy and scanning electron microscopy (SEM), were employed. As assessed by cell viability assay, chitosan showed significant inhibitory effects on the planktonic cells and the biofilm of C. albicans in a dose-dependent manner. Fluorescence microscopy and SEM assays confirmed that the chitosan-treated group showed delayed C. albicans biofilm formation with defect morphological features, due to the inhibitory effects of the vast majority of fungal cell growth. In conclusion, C. albicans biofilms were compromised by the treatment with chitosan, providing an alternative therapeutic strategy against the fungal biofilms in the medical devices. PMID:25120626

PU, YU; LIU, AIBO; ZHENG, YUQIANG; YE, BIN

2014-01-01

370

Chitosan-nanosilica hybrid materials: Preparation and properties  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

371

Highly efficient adsorption of chlorophenols onto chemically modified chitosan  

NASA Astrophysics Data System (ADS)

A novel chemically modified chitosan CS-SA-CD with phenol and ?-cyclodextrin groups was prepared. The adsorptions of phenol, 2-chlorophenol (2-CP), 4-chlorophenol (4-CP), 2,4-dichlorophenol (DCP) and 2,4,6-trichlorophenol (TCP) on the functional chitosan from aqueous solution were investigated. CS-SA-CD exhibited excellent adsorption ability for chlorophenols especially for DCP and TCP. The maximum adsorption capacities of phenol, 2-CP, 4-CP, DCP and TCP on CS-SA-CD were 59.74, 70.52, 96.43, 315.46 and 375.94 mg/g, respectively. The scanning electron microscope and Brunauer-Emmett-Teller analyses revealed that the introduction of phenol group changed the surface morphology and surface properties of chitosan. The modified chitosan CS-SA-CD possesses larger surface areas (4.72 m2/g), pore volume (7.29 × 10-3 mL/g) and average pore diameter (59.99 Å) as compared to those of chitosan 3.27 m2/g, 2.00 × 10-3 mL/g and 15.95 Å, respectively. The enhanced adsorption of chlorophenols was also attributed to the interaction of hydrogen bond between Cl atom and sbnd OH group. The adsorption of chlorophenols on CS-SA-CD followed the pseudo-second-order kinetic model. Adsorbent could be regenerated easily and the regenerated CS-SA-CD remained 80-91% adsorption efficiency.

Zhou, Liang-Chun; Meng, Xiang-Guang; Fu, Jing-Wei; Yang, Yu-Chong; Yang, Peng; Mi, Chun

2014-02-01

372

Antimicrobial finish of textiles by chitosan UV-curing.  

PubMed

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

Ferrero, Franco; Periolatto, Monica

2012-06-01

373

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

374

Improving effects of chitosan nanofiber scaffolds on osteoblast proliferation and maturation  

PubMed Central

Osteoblast maturation plays a key role in regulating osteogenesis. Electrospun nanofibrous products were reported to possess a high surface area and porosity. In this study, we developed chitosan nanofibers and examined the effects of nanofibrous scaffolds on osteoblast maturation and the possible mechanisms. Macro- and micro observations of the chitosan nanofibers revealed that these nanoproducts had a flat surface and well-distributed fibers with nanoscale diameters. Mouse osteoblasts were able to attach onto the chitosan nanofiber scaffolds, and the scaffolds degraded in a time-dependent manner. Analysis by scanning electron microscopy further showed mouse osteoblasts adhered onto the scaffolds along the nanofibers, and cell–cell communication was also detected. Mouse osteoblasts grew much better on chitosan nanofiber scaffolds than on chitosan films. In addition, human osteoblasts were able to adhere and grow on the chitosan nanofiber scaffolds. Interestingly, culturing human osteoblasts on chitosan nanofiber scaffolds time-dependently increased DNA replication and cell proliferation. In parallel, administration of human osteoblasts onto chitosan nanofibers significantly induced osteopontin, osteocalcin, and alkaline phosphatase (ALP) messenger (m)RNA expression. As to the mechanism, chitosan nanofibers triggered runt-related transcription factor 2 mRNA and protein syntheses. Consequently, results of ALP-, alizarin red-, and von Kossa-staining analyses showed that chitosan nanofibers improved osteoblast mineralization. Taken together, results of this study demonstrate that chitosan nanofibers can stimulate osteoblast proliferation and maturation via runt-related transcription factor 2-mediated regulation of osteoblast-associated osteopontin, osteocalcin, and ALP gene expression. PMID:25246786

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

2014-01-01

375

Does the use of chitosan contribute to oxalate kidney stone formation?  

PubMed

Chitosan is widely used in the biomedical field due its chemical and pharmacological properties. However, intake of chitosan results in renal tissue accumulation of chitosan and promotes an increase in calcium excretion. On the other hand, the effect of chitosan on the formation of calcium oxalate crystals (CaOx) has not been described. In this work, we evaluated the antioxidant capacity of chitosan and its interference in the formation of CaOx crystals in vitro. Here, the chitosan obtained commercially had its identity confirmed by nuclear magnetic resonance and infrared spectroscopy. In several tests, this chitosan showed low or no antioxidant activity. However, it also showed excellent copper-chelating activity. In vitro, chitosan acted as an inducer mainly of monohydrate CaOx crystal formation, which is more prevalent in patients with urolithiasis. We also observed that chitosan modifies the morphology and size of these crystals, as well as changes the surface charge of the crystals, making them even more positive, which can facilitate the interaction of these crystals with renal cells. Chitosan greatly influences the formation of crystals in vitro, and in vivo analyses should be conducted to assess the risk of using chitosan. PMID:25551781

Fernandes Queiroz, Moacir; Melo, Karoline Rachel Teodosio; Sabry, Diego Araujo; Sassaki, Guilherme Lanzi; Rocha, Hugo Alexandre Oliveira

2014-01-01

376

Does the Use of Chitosan Contribute to Oxalate Kidney Stone Formation?  

PubMed Central

Chitosan is widely used in the biomedical field due its chemical and pharmacological properties. However, intake of chitosan results in renal tissue accumulation of chitosan and promotes an increase in calcium excretion. On the other hand, the effect of chitosan on the formation of calcium oxalate crystals (CaOx) has not been described. In this work, we evaluated the antioxidant capacity of chitosan and its interference in the formation of CaOx crystals in vitro. Here, the chitosan obtained commercially had its identity confirmed by nuclear magnetic resonance and infrared spectroscopy. In several tests, this chitosan showed low or no antioxidant activity. However, it also showed excellent copper-chelating activity. In vitro, chitosan acted as an inducer mainly of monohydrate CaOx crystal formation, which is more prevalent in patients with urolithiasis. We also observed that chitosan modifies the morphology and size of these crystals, as well as changes the surface charge of the crystals, making them even more positive, which can facilitate the interaction of these crystals with renal cells. Chitosan greatly influences the formation of crystals in vitro, and in vivo analyses should be conducted to assess the risk of using chitosan. PMID:25551781

Queiroz, Moacir Fernandes; Teodosio Melo, Karoline Rachel; Sabry, Diego Araujo; Sassaki, Guilherme Lanzi; Rocha, Hugo Alexandre Oliveira

2014-01-01

377

Synthesis of chitosan-gallic acid conjugate: structure characterization and in vitro anti-diabetic potential.  

PubMed

In this study, chitosan grafted copolymer with gallic acid (GA) was synthesized by a novel and efficient free radical mediated method. The optimal grafting conditions, structural characterization, ?-glucosidase and ?-amylase inhibitory activities of chitosan grafted copolymers were investigated. Results showed that the maximum grafting ratio (128.3 mg GA equivalents/g) was obtained at 12 h with 5 g/L chitosan, 16 g/L GA, 2 g/L ascorbic acid and 0.2 M hydrogen peroxide. UV-vis, Fourier-transform infrared and nuclear magnetic resonance spectroscopy all confirmed the successful grafting of GA onto chitosan. The conjugation of GA onto chitosan probably occurred between amine (C-2), hydroxyl groups (C-3 and C-6) of chitosan and carboxyl groups of GA, forming amide and ester linkages, respectively. Differential scanning calorimetry and X-ray diffraction spectra indicated that GA grafted chitosan (GA-g-chitosan) had decreased thermal stability and crystallinity as compared to chitosan. Notably, GA-g-chitosan showed increased ?-glucosidase and ?-amylase inhibitory activity with the increase of grafting ratio. These results indicated the potential of GA-g-chitosan in the development of an effective anti-diabetic agent. PMID:24076198

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

2013-11-01

378

Characterization and potential applications of gamma irradiated chitosan and its blends with poly(vinyl alcohol).  

PubMed

Naturally available chitosan (CHI), of high molecular weight, results in reduced efficiency of these polymers for antibacterial activity. In this regard, irradiation is a widely used method for achieving reduction in molecular weight of polymers, which may improve some of its characteristics. Chitosan was extracted from crab shells and degraded by gamma radiations. Effect of radiation dose on chitosan was analyzed by Fourier transform infrared (FTIR) spectroscopy. Furthermore, the irradiated chitosan was blended with poly(vinyl alcohol) (PVA) and crosslinked with tetraethylorthosilicate (TEOS) into membranes. The membranes were found to be smooth, transparent and macroporous in structure, exhibiting high tensile strength (TS: 27-47 MPa) and elongation at break (EB: 292.6-407.3%). The effect of molecular weight of chitosan and chitosan blends on antibacterial activity was determined. Irradiated low molecular weight chitosan and membranes showed strong antibacterial activity against Escherichia coli and Bacillus subtilis. PMID:24418341

Bano, Ijaz; Ghauri, Muhammad Afzal; Yasin, Tariq; Huang, Qingrong; Palaparthi, Annie D'Souza

2014-04-01

379

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

PubMed

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

Wang, Jianlong; Chen, Can

2014-05-01

380

A comparative study on the chitosan membranes prepared from glycine hydrochloride and acetic acid.  

PubMed

In this study, glycine hydrochloride (Gly·HCl) is confirmed to be a promising solvent for dissolving native chitosan and preparing regenerated chitosan membrane. As compared with the chitosan membrane prepared from traditional acetic acid, the membrane prepared from Gly·HCl by dry technique shows excellent tensile strength and initial modulus, i.e. 103.8MPa and 3.2GPa, respectively, which is superior to any chitosan membrane and most chitosan blend membranes reported in literatures. Besides, scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXD) and Fourier transform infrared spectroscopy (FT-IR) were used to visualize the difference between the two kind of regenerated chitosan membranes. The SEM results show that the membrane prepared from Gly·HCl by dry technique presents a novel structure, which ensures its high tenacity. Furthermore, the chitosan microporous membranes were also prepared using PEG as porogen. PMID:23121935

Ma, Bomou; Li, Xiang; Qin, Aiwen; He, Chunju

2013-01-16

381

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

PubMed

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

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

2014-06-01

382

Swelling and surface modification of ultrathin chitosan films  

NASA Astrophysics Data System (ADS)

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

Murray, Chris

2005-03-01

383

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.

384

Chitosan and its derivatives for tissue engineering applications.  

PubMed

Tissue engineering is an important therapeutic strategy for present and future medicine. Recently, functional biomaterial researches have been directed towards the development of improved scaffolds for regenerative medicine. Chitosan is a natural polymer from renewable resources, obtained from shell of shellfish, and the wastes of the seafood industry. It has novel properties such as biocompatibility, biodegradability, antibacterial, and wound-healing activity. Furthermore, recent studies suggested that chitosan and its derivatives are promising candidates as a supporting material for tissue engineering applications owing to their porous structure, gel forming properties, ease of chemical modification, high affinity to in vivo macromolecules, and so on. In this review, we focus on the various types of chitosan derivatives and their use in various tissue engineering applications namely, skin, bone, cartilage, liver, nerve and blood vessel. PMID:17884325

Kim, In-Yong; Seo, Seog-Jin; Moon, Hyun-Seuk; Yoo, Mi-Kyong; Park, In-Young; Kim, Bom-Chol; Cho, Chong-Su

2008-01-01

385

Gum ghatti-chitosan polyelectrolyte nanoparticles: preparation and characterization.  

PubMed

The objective of the present study was to optimize the interaction between gum ghatti and chitosan to prepare polyelectrolyte nanoparticles using ofloxacin as the model drug. The effect of varying the concentration of gum ghatti, chitosan, Pluronic F-127, and ofloxacin on particle size and entrapment efficiency was studied using central composite experimental design. The optimized calculated parameters were concentrations of gum ghatti (0.12% w/v), chitosan (0.22% w/v), Pluronic F-127 (0.05% w/v), ofloxacin (0.1% w/v), which provided polyelectrolyte nanoparticles of size 121.6 nm and 94.49% entrapment. On screening for antibacterial activity, it was observed that polyelectrolyte nanoparticles had antibacterial activity comparable to the aqueous solution. Further, it was observed that polyelectrolyte nanoparticles released the drug by diffusion through the matrix following Higuchi's square-root kinetics. PMID:23924761

Shelly; Ahuja, Munish; Kumar, Ashok

2013-10-01

386

Study of polyelectrolyte complexes of chitosan and sulfoethyl cellulose  

SciTech Connect

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 {mu}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{sub 3}{sup +}) and negatively charged sulfoethyl cellulose groups (-SO{sub 3}{sup -}) during the growth of polyelectrolyte complexes results in a packing of chitosan chains in the multilayer film.

Baklagina, Yu. G., E-mail: membrane@hq.macro.ru; Kononova, S. V.; Petrova, V. A.; Kruchinina, E. V.; Nud'ga, L. A. [Russian Academy of Sciences, Institute of Macromolecular Compounds (Russian Federation)] [Russian Academy of Sciences, Institute of Macromolecular Compounds (Russian Federation); Romanov, D. P. [Russian Academy of Sciences, Grebenshchikov Institute of Silicate Chemistry (Russian Federation)] [Russian Academy of Sciences, Grebenshchikov Institute of Silicate Chemistry (Russian Federation); Klechkovskaya, V. V.; Orekhov, A. S. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)] [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Bogomazov, A. V.; Arkhipov, S. N. [ZAO Nauchnye Pribory (Russian Federation)] [ZAO Nauchnye Pribory (Russian Federation)

2013-03-15

387

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

388

Differential response of encapsulated nucleus pulposus and bone marrow stem cells in isolation and coculture in alginate and chitosan hydrogels.  

PubMed

Cell-based therapies may hold significant promise for the treatment of early stage degeneration of the intervertebral disc (IVD). Given their propensity to proliferate and ability to form multiple tissue types, mesenchymal stem cells (MSCs) have been proposed as a potential cell source to promote repair of the nucleus pulposus (NP). However, for any successful cell-based therapy, a carrier biomaterial may be essential for targeted delivery providing key biophysical and biochemical cues to facilitate differentiation of MSCs. Two widely used biomaterials for NP regeneration are chitosan and alginate. The primary objective of this study was to assess the influence of alginate and chitosan hydrogels on bone marrow stem cells (BM) and NP cells in isolation or in coculture. A secondary objective of this study was to investigate coculture seeding density effects of BM and NP cells and simultaneously explore which cell type is responsible for matrix formation in a cocultured environment. Porcine NP and BM cells were encapsulated in alginate and chitosan hydrogels separately at two seeding densities (4×10(6) and 8×10(6) cells/mL) or in coculture (1:1, 8×10(6) cells/mL). Constructs (diameter=5?mm, height=3?mm) were maintained under IVD-like conditions [low-glucose, low (5%) oxygen] with or without transforming growth factor-?3 (TGF-?3) supplementation for 21 days. Results demonstrated differential viability depending on hydrogel type. NP cells remained viable in both biomaterial types whereas BM viability was diminished in chitosan. Further, hydrogel type was found to regulate sulfated glycosaminoglycan (sGAG) and collagen accumulation. Specifically, alginate better supports sGAG accumulation and collagen type II deposition for both NP and BM cell types compared with chitosan. Having identified that alginate more readily supports cell viability and matrix accumulation, we further explored additional effects of seeding density ratios (NP:BM-1:1, 1:2) for coculture studies. Interestingly, in coculture conditions, the BM cell population declined in number while NP cells increased, indicating that MSCs may in fact be signaling NP cells to proliferate rather than contributing to matrix formation. These findings provide exciting new insights on the potential of MSCs for NP tissue regeneration strategies. PMID:25060596

Naqvi, Syeda Masooma; Buckley, Conor Timothy

2015-01-01

389

Chitosan and O-carboxymethyl chitosan modified Fe3O4 for hyperthermic treatment  

NASA Astrophysics Data System (ADS)

In this study magnetic fluids were manufactured by the adsorption of chitosan (CS) and O-carboxymethyl chitosan (OCMCS) on Fe3O4 nanoparticles to be used as hyperthermic thermoseeds. Fe3O4 particles were characterized by physico-chemical methods such as: thermogravimetry analysis (TGA), x-ray diffraction (XRD), Raman spectrum, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and vibrating sample magnetometer (VSM). The SEM images and XRD patterns showed that the synthesized Fe3O4 nanoparticles were of single phase and spherical shape with 10–15?nm in diameter. The VSM measurements showed that Fe3O4 particles were superparamagnetic with saturation magnetization of 70?emu?g?1. The adsorbed layers of CS and OCMCS on the magnetite surface (Fe3O4/CS) and (Fe3O4/OCMCS) were confirmed by FTIR, Raman spectra and SEM. In the ac magnetic field of 80?Oe and 236?kHz, the saturation heating temperatures of the sample Fe3O4/CS and Fe3O4/OCMCS were 100 and 98?°C, respectively. At the same concentration of Fe3O4 nanoparticles in suspension, the two magnetic fluids exhibited quite high heating capacity, with different behaviors of concentration dependence. The Fe3O4/CS and Fe3O4/OCMCS nanoparticles would serve as good thermoseeds for localized hyperthermia treatment of cancers.

Thu Trang Mai, Thi; Thu Ha, Phuong; Pham, Hong Nam; Thu Huong Le, Thi; Linh Pham, Hoai; Bich Hoa Phan, Thi; Tran, Dai Lam; Phuc Nguyen, Xuan

2012-03-01

390

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

PubMed

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

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

2014-06-01

391

Preparation of curcumin-loaded pluronic F127/chitosan nanoparticles for cancer therapy  

NASA Astrophysics Data System (ADS)

Nanoparticles (NPs) have been proven to be an effective delivery system with few side effects for anticancer drugs. In this study, curcumin-loaded NPs have been prepared by an ionic gelation method using chitosan (Chi) and pluronic®F-127 (PF) as carriers to deliver curcumin to the target cancer cells. Prepared NPs were characterized using Zetasizer, fluorescence microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Our results showed that the encapsulation efficiency of curcumin was approximately 50%. The average size of curcumin-loaded PF/Chi NPs was 150.9 nm, while the zeta potential was 5.09 mV. Cellular uptake of curcumin-loaded NPs into HEK293 cells was confirmed by fluorescence microscopy.

Phuc Le, Thi Minh; Phuc Pham, Van; Lua Dang, Thi Minh; Huyen La, Thi; Hanh Le, Thi; Huan Le, Quang

2013-06-01

392

Biodegradable chitosan particles induce chemokine release and negligible arginase-1 activity compared to IL-4 in murine bone marrow-derived macrophages  

E-print Network

Biodegradable chitosan particles induce chemokine release and negligible arginase-1 activity January 2011 Available online xxxx Keywords: Chitosan Bone marrow-derived macrophages Macrophage implicated in the therapeutic activity of biodegradable chitosan on wound healing, however, the mechanisms

Buschmann, Michael

393

Polarized light-stimulated enzymatic hydrolysis of chitin and chitosan.  

PubMed

Illumination with white linearly polarized light (WLPL) stimulated chitinase and chitosanase in their degradation of chitin and chitosan, respectively. Enzymes were illuminated at room temperature in separate vessels, then admixed in reactors containing polysaccharides. Hydrolysis of chitosan to glucosamine followed first order kinetics whereas hydrolysis of chitin to N-acetylglucosamine deviated from the first order kinetics. In both cases, an increase in the rate of hydrolysis depended on the illumination time. Efficient degradation required up to 60 min exposure of the enzyme to WLPL. PMID:18823881

Konieczna-Molenda, Anna; Fiedorowicz, Maciej; Zhong, Wei; Tomasik, Piotr

2008-12-01

394

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

395

Chitosan coated cotton gauze for antibacterial water filtration.  

PubMed

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

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

2014-03-15

396

Study on the flocculating properties of quaternized carboxymethyl chitosan  

Microsoft Academic Search

Summary  Quaternized carboxymethyl chitosan (QCMC) was prepared through the grafting reaction of carboxymethyl chitosan (CMC) with\\u000a 3-chloro-2-hydroxypropyl trimethylammonium chloride (CTA) as a quaternizing agent in 2-propanol medium under basic condition.\\u000a The synthetic conditions for QCMC were as follows: 40.0% of NaOH aqueous solution as catalyst; reaction temperature, 60.0 ?C\\u000a and reaction time, 10.0 h; NaOH\\/CMC, 0.50; CTA\\/CMC, 1.50 (mass ratio). The characterization by

Zhao-sheng Cai; Zhan-qian Song; Shi-bin Shang; Chun-sheng Yang

2007-01-01

397

Coordination study of chitosan and Fe 3+  

NASA Astrophysics Data System (ADS)

The coordination of Fe 3+ with chitosan was studied, considering the type of acid for dissolving the ligand, the pH for the medium, and the metal-biopolymer ratio. Potentiometric and ultraviolet-visible titrations, infrared spectroscopy, thermal analysis and X-ray diffraction were employed. The polymer coordinates with the metal cation through the amino and hydroxyl groups in the entire pH range studied, with pH values around 3-6 being the most important region. The logarithms of the overall binding constants for the equilibria were: A: Chit-Fe, ? A 16.06 ± 0.07; B: Chit 2-FeH, ? B 32.64 ± 0.07; C: Chit 3-Fe, ? C 35.6 ± 0.1; D: Chit 3-FeH, ? D 49.0 ± 0.2, respectively. The coordination is made either by the amino or/and the hydroxyl groups with water molecules or/and chloride ions completing the coordination sphere for the metal giving rise to among other possible, di- to hexacoordinated complexed species [FeNO 2Cl 3], [FeN 2O 2Cl 2], [FeN 3O 3] and [FeN 2O 4].

Hernández, Raúl B.; Franco, Ana Paula; Yola, Oscar R.; López-Delgado, Aurora; Felcman, Judith; Recio, María Angeles L.; Mercê, Ana Lucia Ramalho

2008-04-01

398

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

PubMed

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

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

2014-01-01

399

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

PubMed Central

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

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

2014-01-01

400

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

2013-01-01

401

Evaluation of chitosan based vaginal bioadhesive gel formulations for antifungal drugs.  

PubMed

The aim of the present study was to evaluate chitosan as a vaginal mucoadhesive gel base for econazole nitrate and miconazole nitrate. To this aim, different types of chitosan with different molecular masses and viscosity properties [low molecular mass chitosan (viscosity: 20,000 mPa s), medium molecular mass chitosan (viscosity: 200,000 mPa s), high molecular mass chitosan (viscosity: 800,000 mPa s)] have been used. First, rheological studies were conducted on chitosan gels. Mechanical, syringeability and mucoadhesive properties of chitosan gels were determined. Release profiles of econazole nitrate and miconazole nitrate from chitosan gels were obtained and evaluated kinetically. In addition, anticandidal activities of formulations were determined. Finally, vaginal retention of chitosan gels in rats was evaluated by in vivo distribution studies. Based on the results, it can be concluded that gels prepared with medium molecular mass chitosan might be effectively used for different antifungal agents in the treatment of vaginal candidiosis, since it has high mucoadhesiveness, suitable mechanical and release properties with good vaginal retention. PMID:24914716

Senyi?it, Zeynep Ay; Karavana, Sinem Yaprak; Eraç, Bayri; Gürsel, Ozge; Limoncu, Mine Ho?gör; Balo?lu, Esra

2014-06-01

402

Hydrolysis of a chitosan-induced milk aggregate by pepsin, trypsin and pancreatic lipase.  

PubMed

The addition of chitosan to whole milk results in dose dependent destabilization and coagulation of the casein micelles and milk fat. The present study evaluates how the presence of chitosan could affect the hydrolysis of this chitosan-induced aggregate by different gastrointestinal proteases (pepsin and trypsin) and by pancreatic lipase. The chitosan-milk aggregate was hydrolyzed by pepsin and trypsin, as evaluated by the UV absorbance of TCA-soluble peptides and by urea-PAGE. The kinetics and extent of hydrolysis were independent of the casein being soluble or aggregated. The release of soluble peptides from the aggregate was independent of the presence of chitosan. A progressive inhibition of pancreatic lipase was observed in proportion to the increase in molecular weight of the chitosan employed to induce the formation of the aggregate. Interestingly, the presence of chitosan not only affected the initial velocity of the reaction, but also reduced its extent. The results indicate that a milk aggregate induced by chitosan was very well digested by gastric and intestinal proteases independently of the molecular weight of the chitosan used, and that the aggregate could retain the lipid-lowering effect of chitosan. PMID:11791713

Ausar, S F; Landa, C A; Bianco, I D; Castagna, L F; Beltramo, D M

2001-11-01

403

Microwave-assisted degradation of chitosan for a possible use in inhibiting crop pathogenic fungi.  

PubMed

Degradation of chitosan by H(2)O(2) under microwave irradiation was investigated. The oxidative degradation of chitosan was highly accelerated by microwave irradiation under the condition of low temperature and low concentration of H(2)O(2). The degraded chitosans with low molecular weight (M(w)) were characterized by gel permeation chromatography, Fourier-transform infrared spectroscopy, ultraviolet-visible spectroscopy, X-ray diffraction and elemental analysis. The decrease of M(w) led to transformation of crystal structure and increase of water solubility, whereas no significant chemical structure change in the backbone of chitosan was observed. Antifungal activities of chitosans with different M(w) against crop pathogenic fungi Phomopsis asparagi, Fusarium oxysoporum f. sp. Vasinfectum and Stemphylium solani were investigated at the concentrations of 100, 200 and 400 mg/L. All degraded chitosans with low M(w) exhibited enhanced antifungal activity compared with original chitosan and the chitosan of 41.2 kDa showed the highest activity. At 400 mg/L, the chitosan of 41.2 kDa inhibited growth of P. asparagi at 89.3%, stronger than polyoxin and triadimefon, the inhibitory effects of which were found to be 55.5% and 68.5%. All the results indicated that oxidative degradation under microwave irradiation was a promising technique for large-scale production of low M(w) chitosan for use in crop protection. PMID:22829054

Li, Kecheng; Xing, Ronge; Liu, Song; Qin, Yukun; Meng, Xiangtao; Li, Pengcheng

2012-12-01

404

In vitro liberation of indomethacin from chitosan gels containing microemulsion in different dissolution mediums.  

PubMed

The objective of this research is to outline the liberation of indomethacin from different chitosan gels containing O/W microemulsion. The influence of surfactant, sodium lauryl sulfate, in two concentrations (0.5% and 0.75%, w/w) was determined in dissolution medium on the release of indomethacin, which was used as poor water-soluble model drug. Chitosan gels were prepared in four different concentrations of chitosan-1%, 1.5%, 2%, and 3% (w/w). Microemulsion enhanced the liberation of the indomethacin from chitosan gels into all dissolution mediums. Adding the surfactant into phosphate-buffered saline decreased the amount of liberated indomethacin from microemulsion, gel mixture, but increased the drug liberation from pure chitosan gels. It was detected that with the increased concentration of chitosan in the samples, the amount of indomethacin liberated (p < 0.05) also increased. A conclusion was drawn that the liberation of indomethacin from chitosan gels was influenced by increased pH of the samples. The high viscosity induced a higher release of indomethacin from 3% (w/w) chitosan hydrogel at pH 5.8 as compared with 3% (w/w) chitosan hydrogel at pH 3.8. The highest percentage of released indomethacin was determined when a mixture of microemulsion gel with higher chitosan content was used. PMID:25318853

Starýchová, Lenka; Žabka, Marián; Špaglová, Miroslava; ?uchorová, Mária; Vitková, Mária; ?ierna, Martina; Bartoníková, Kamila; Gardavská, Klára

2014-12-01

405

Emulsion Electrospinning as an Approach to Fabricate PLGA/Chitosan Nanofibers for Biomedical Applications  

PubMed Central

Novel nanofibers from blends of polylactic-co-glycolic acid (PLGA) and chitosan have been produced through an emulsion electrospinning process. The spinning solution employed polyvinyl alcohol (PVA) as the emulsifier. PVA was extracted from the electrospun nanofibers, resulting in a final scaffold consisting of a blend of PLGA and chitosan. The fraction of chitosan in the final electrospun mat was adjusted from 0 to 33%. Analyses by scanning and transmission electron microscopy show uniform nanofibers with homogenous distribution of PLGA and chitosan in their cross section. Infrared spectroscopy verifies that electrospun mats contain both PLGA and chitosan. Moreover, contact angle measurements show that the electrospun PLGA/chitosan mats are more hydrophilic than electrospun mats of pure PLGA. Tensile strengths of 4.94?MPa and 4.21?MPa for PLGA/chitosan in dry and wet conditions, respectively, illustrate that the polyblend mats of PLGA/chitosan are strong enough for many biomedical applications. Cell culture studies suggest that PLGA/chitosan nanofibers promote fibroblast attachment and proliferation compared to PLGA membranes. It can be assumed that the nanofibrous composite scaffold of PLGA/chitosan could be potentially used for skin tissue reconstruction. PMID:24689041

Tavanai, Hossein; Hilborn, Jöns; Donzel-Gargand, Olivier; Leifer, Klaus; Arpanaei, Ayyoob

2014-01-01

406

Synthesis and optimization of chitosan nanoparticles: Potential applications in nanomedicine and biomedical engineering  

PubMed Central

Background: Chitosan nanoparticles have become of great interest for nanomedicine, biomedical engineering and development of new therapeutic drug release systems with improved bioavailability, increased specificity and sensitivity, and reduced pharmacological toxicity. The aim of the present study was to synthesis and optimize of the chitosan nanoparticles for industrial and biomedical applications. Methods: Fe3O4 was synthesized and optimized as magnetic core nanoparticles and then chitosan covered this magnetic core. The size and morphology of the nano-magnetic chitosan was analyzed by scanning electron microscope (SEM). Topography and size distribution of the nanoparticles were shown with two-dimensional and three-dimensional images of atomic force microscopy (AFM). The nanoparticles were analyzed using transmission electron microscopy (TEM). Results: The chitosan nanoparticles prepared in the experiment exhibited white powder shape. The SEM micrographs of the nano-magnetic chitosan showed that they were approximately uniform spheres. The unmodified chitosan nanoparticles composed of clusters of nanoparticles with sizes ranging from 10 nm to 80 nm. AFM provides a three-dimensional surface profile. The TEM image showed physical aggregation of the chitosan nanoparticles. Conclusion: The results show that a novel chitosan nanoparticle was successfully synthesized and characterized. It seems that this nanoparticle like the other chitosan nano particles has potential applications for nanomedicine, biomedical engineering, industrial and pharmaceutical fields. PMID:25202443

Ghadi, Arezou; Mahjoub, Soleiman; Tabandeh, Fatemeh; Talebnia, Farid

2014-01-01

407

Recent Advances in Drugs and Prodrugs Design of Chitosan  

Microsoft Academic Search

The aim of this review is to outline the recent advances in chitosan molecular modeling, especially its usage as a prodrug or drug in a field of antibacterial, anticarcinogenic and antioxidant activity. Polymeric materials like peptides, polysaccharides and other natural products have recently attracted attention as biodegradabile drug car- riers. They can optimize clinical drug application, minimize the undesirable drug

J. Vinsova; E. Vavrikova

408

Chitosan/alkylethoxy carboxylates: a surprising variety of structures.  

PubMed

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

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

2014-02-25

409

Chitosan and its antimicrobial potential – a critical literature survey  

PubMed Central

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

Raafat, Dina; Sahl, Hans?Georg

2009-01-01

410

Uptake and cytotoxicity of chitosan nanoparticles in human liver cells  

Microsoft Academic Search

Despite extensive research into the biomedical and pharmaceutical applications of nanoparticles, and the liver being the main detoxifying organ in the human body, there are limited studies which delineate the hepatotoxicity of nanoparticles. This paper reports on the biological interactions between liver cells and chitosan nanoparticles, which have been widely recognised as biocompatible. Using the MTT assay, human liver cells

Jing Wen Loh; George Yeoh; Martin Saunders; Lee-Yong Lim

2010-01-01

411

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

PubMed

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

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

2007-08-01

412

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

413

Transforming chitosan into N-doped graphitic carbon electrocatalysts.  

PubMed

Chitosan, the only alkaline polysaccharide in nature with rich nitrogen content, is used as the sole precursor to obtain N-doped graphitic carbon-based ORR electrocatalysts. The findings of this work demonstrate that cheap, plentiful and renewable biomasses can be transformed into high value functional carbon materials. PMID:25486248

Wu, T X; Wang, G Z; Zhang, X; Chen, C; Zhang, Y X; Zhao, H J

2014-12-23

414

Abatement of Azo Dye from Wastewater Using Bimetal-Chitosan  

PubMed Central

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

Asgari, Ghorban; Farjadfard, Sima

2013-01-01

415

Superior preclinical efficacy of gemcitabine developed as chitosan nanoparticulate system.  

PubMed

Gemcitabine, an anticancer nucleoside analogue, undergoes rapid enzymatic degradation following intravenous injection. This necessitates the administration of a high order of doses to observe a required therapeutic response, while such high doses result in significant side effects. To improve the intravenous delivery of gemcitabine and simultaneously enhance its antitumor activity, we have investigated its incorporation into a drug nanoplatform based on the biodegradable polymer chitosan. Two gemcitabine loading methods have been investigated: (i) entrapment into the polymeric network (entrapment procedure): drug incorporation prior to the coacervation process that leads to the formation of gemcitabine-loaded chitosan (GemChit) nanoparticles; and (ii) surface deposition onto already formed chitosan nanoparticles after incubation in gemcitabine solution (adsorption procedure). The former method produced much higher gemcitabine loading values and a sustained release profile. The main factors determining the gemcitabine loading and release kinetic have also been analyzed. Following intravenous injection, the GemChit formulation displayed a significantly improved antitumor activity comparatively to free gemcitabine, which was further confirmed by histology and immunohistochemistry studies, suggesting the potential of this chitosan-based gemcitabine nanomedicine for the effective treatment of tumors. PMID:21117615

Arias, José L; Reddy, L Harivardhan; Couvreur, Patrick

2011-01-10

416

Physichemical property and morphology of 5-fluorouracil loaded chitosan nanoparticles  

Microsoft Academic Search

fluorouracil (5-FU), a hydrophilic anticancer drug, was successfully encapsulated into biodegradable chitosan (CS) to form CS\\/5-FU nanoparticles (NPs) by ionic crosslinking technology. The surface morphology of the pure CS NPs and 5- FU loaded NPs was investigated by scanning electron microscopy (SEM); the interaction between CS and 5- florouracil (5-FU) was studied by Fourier transform infrared spectrometer (FTIR); the physical

Puwang Li; Yichao Wang; Zheng Peng; Mary F. She; Lingxue Kong

2010-01-01

417

Formulation and evaluation of chitosan solid lipid nanoparticles of carbamazepine  

PubMed Central

The present work aims at preparing aqueous suspension of Solid lipid Nanoparticles containing Chitosan (CT) which is a biopolymer that exhibits a number of interesting properties which include controlled drug delivery. Carbamezapine (CBZ) is a lipophilic drug which shows it antiepileptic activity by inactivating sodium channels. The solid lipid Nanoparticles (SLN) of Chitosan-CBZ were prepared by using solvent injection method using ethanol as organic solvent. The prepared SLN formulations exhibited high encapsulation efficiency, high physical stability. The drug incorporated SLNs have demonstrated that the controlled release patterns of the drug for prolonged period. The prepared SLNs were characterized for surface morphology by SEM analysis, entrapment efficiency, zeta potential, FTIR, DSC and In-vitro diffusion studies. The hydrodynamic mean diameter and zeta potential were 168.7 ±1.8?nm and ?28.9 ±2.0?mV for SLN-chitosan-CBZ respectively. Therefore chitosan-SLN can be good candidates to encapsulate CBZ and to increase its therapeutic efficacy in the treatment of Epilepsy. PMID:22695222

2012-01-01

418

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. PMID:22312270

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

2012-01-01

419

Uptake and cytotoxicity of chitosan nanoparticles in human liver cells  

SciTech Connect

Despite extensive research into the biomedical and pharmaceutical applications of nanoparticles, and the liver being the main detoxifying organ in the human body, there are limited studies which delineate the hepatotoxicity of nanoparticles. This paper reports on the biological interactions between liver cells and chitosan nanoparticles, which have been widely recognised as biocompatible. Using the MTT assay, human liver cells were shown to tolerate up to 4 h of exposure to 0.5% w/v of chitosan nanoparticles (18 {+-} 1 nm, 7.5 {+-} 1.0 mV in culture medium). At nanoparticle concentrations above 0.5% w/v, cell membrane integrity was compromised as evidenced by leakage of alanine transaminase into the extracellular milieu, and there was a dose-dependent increase in CYP3A4 enzyme activity. Uptake of chitosan nanoparticles into the cell nucleus was observed by confocal microscopic analysis after 4 h exposure with 1% w/v of chitosan nanoparticles. Electron micrographs further suggest necrotic or autophagic cell death, possibly caused by cell membrane damage and resultant enzyme leakage.

Loh, Jing Wen [Laboratory for Drug Delivery, Pharmacy, University of Western Australia, 35 Stirling Hwy, Crawley, 6009 (Australia); Yeoh, George [School of Biomedical, Biomolecular and Chemical Sciences, University of Western Australia, 35 Stirling Hwy, Crawley, 6009 (Australia); Centre for Medical Research, Western Australian Institute for Medical Research, Nedlands, WA 6009 (Australia); Saunders, Martin [Centre for Microscopy, Characterisation and Analysis, University of Western Australia, 35 Stirling Hwy, Crawley, 6009 (Australia); Lim, Lee-Yong, E-mail: limly@cyllene.uwa.edu.a [Laboratory for Drug Delivery, Pharmacy, University of Western Australia, 35 Stirling Hwy, Crawley, 6009 (Australia); School of Biomedical, Biomolecular and Chemical Sciences, University of Western Australia, 35 Stirling Hwy, Crawley, 6009 (Australia)

2010-12-01

420

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

421

Preparation and characterisation of chitosan microspheres for antioxidant delivery  

Microsoft Academic Search

Encapsulation of olive leaf extract (OLE) in chitosan micropsheres was carried out by a spray-drying process. The interaction of polyphenolic compounds (PPCs) present in OLE within the polysaccharide matrix was studied using various physico-chemical techniques. Both the placebo and the OLE loaded microspheres were characterised by optical and scanning electron microscopy, particle size distribution analysis, Fourier transform infrared spectroscopy (FTIR)

Shantha L. Kosaraju; Lynette D'ath; Andrew Lawrence

2006-01-01

422

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. PMID:23133478

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

2012-01-01

423

Cocatalyst effect in potassium persulfate initiated grafting onto chitosan  

Microsoft Academic Search

Methyl methacrylate and methyl acrylate were grafted onto chitosan by using potassium persulfate alone as redox initiator and in combination with MnCl2 and CuCl2, as inorganic, and both ammonium tartrate and oxalate as organic cocatalysts. The extent of grafting was found to depend mainly on the nature of the cocatalysts used.

J. Retuert; M. Yazdani-Pedram

1993-01-01

424

Thermodynamic properties of chitosan dodecahydro- closo-dodecaborate  

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

425

Enriched fluoride sorption using alumina/chitosan composite.  

PubMed

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

Viswanathan, Natrayasamy; Meenakshi, S

2010-06-15

426

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

427

Chitosan flocculation of cardboard-mill secondary biological wastewater  

Microsoft Academic Search

Flocculation is a common secondary treatment procedure for the removal of suspended solids, colloids and organic matter present in industrial wastewater. In the present study, the flocculation of cardboard industry wastewater, treated by a biological process in an aerated lagoon, was examined using commercial grade polyaluminium chloride (PAC) and chitosan (CHITO) dissolved in acetic acid as flocculating agents. A series

François Renault; Bertrand Sancey; Jérémie Charles; Nadia Morin-Crini; Pierre-Marie Badot; Peter Winterton; Grégorio Crini

2009-01-01

428

DIRECTION OF IN VITRO CALCIFIED CHITOSAN MEMBRANES FOR TECHNOLOGICAL APPLICATIONS  

Microsoft Academic Search

Some calcium compounds, such as hydroxyapatite (HA), are widely recognized as materials capable of separating proteins, nucleic acids, and viruses in aqueous systems using chromatography. For this reason, exploring alternative routes for forming calcified resins is of great interest. One of these routes is the biomineralization or biomimetic process. The present study analyzes the calcification deposits obtained on chitosan substrates

M. M. BEPPU; C. C. SANTANA

2004-01-01

429

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

PubMed

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

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

2014-10-13

430

Crosslinked chitosan composite membrane for the pervaporation dehydration of alcohol mixtures and enhancement of structural stability of chitosan\\/polysulfone composite membranes  

Microsoft Academic Search

Chitosan composite membranes having a microporous polysulfone substrate were prepared and tested for the pervaporation dehydration of aqueous isopropanol mixtures. When the composite membrane experienced excessive swelling at the feed mixture of high water content, the composite membranes were found to be segregated in structure due to the opposite characteristics to water of chitosan and polysulfone. Efforts to enhance the

Robert Y. M. Huang; Rajinder Pal; Go Young Moon

1999-01-01

431

Imino-chitosan biopolymeric films. Obtaining, self-assembling, surface and antimicrobial properties.  

PubMed

The paper reports the preparation of twelve imino-chitosan biopolymer films by acid condensation of the amino groups of chitosan with various aldehydes, in aqueous medium, followed by slow water removal. FTIR spectroscopy has shown drastic conformation changes of chitosan macromolecular chains - from a stiff coil to a straight one, while wide angle X-ray diffraction evidenced a layered morphology of the biopolymer films. Contact angle and surface free energy determination indicated a higher biocompatibility of the new biopolymers as compared to the chitosan parent, while the microbiological screening demonstrated their self-defense properties against common and virulent pathogen agents. It was concluded that the reversibility of imine forming promotes the self-assembling of imino-chitosan biopolymer films into a lamellar morphology and, on the other hand, the slow release of the antimicrobial aldehyde in the microbiological culture. The obtained results demonstrate that chitosan polyamine is a challenging workbench to functional biodynamic materials. PMID:25498698

Marin, Luminita; Ailincai, Daniela; Mares, Mihai; Paslaru, Elena; Cristea, Mariana; Nica, Valentin; Simionescu, Bogdan C

2015-03-01

432

Should chitosan and tranexamic acid be combined for improved hemostasis after sinus surgery?  

PubMed

Chitosan, a ?-1,4-linked polymer of glucosamine with lesser amounts of N-acetylglucosamine, has well-recognized hemostatic properties. Chitosan is also able to open tight cellular junctions, facilitating paracellular drug transport and delivery. Chitosan, through topical application, facilitates the systemic delivery of analgesic drugs. Theoretically this ability could be used to enhance the local delivery of hemostatic drugs, such as tranexamic acid, improving chitosan's role as a topical dressing. Individually a chitosan-dextran gel and tranexamic acid have been shown to improve hemostasis after endoscopic sinus surgery. A combination of both should lead to improved hemostasis and better postsurgical outcomes. The use of a chitosan/tranexamic acid dressing could have a wide range of potential beneficial applications in a number of other clinical surgical settings. While the initial main application might be as an improved external hemostatic dressing, it should also be useful on a range of internal surgical wounds. PMID:24125578

Bartley, Jim