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1

Gadolinium-loaded chitosan nanoparticles as magnetic resonance imaging contrast agents for the diagnosis of tumor.  

PubMed

The aim of our study was to prepare gadolinium loaded chitosan nanoparticles (Gd-CSNPs) for magnetic resonance imaging (MRI). The chitosan nanoparticles (CSNPs) were prepared by ionic gelation method with sodium tripolyphosphate. The Gd ions were conjugated to the surface of CSNPs through diethylenetriamine pentaacetic acid (DTPA) using N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) to obtain Gd-CSNPs. The physicochemical properties of CSNPs and Gd-CSNPs were measured by transmission electron microscope, dynamic light scattering and inductively coupled plasma optical emission spectroscopy, respectively. The cell toxicity evaluation was performed in mouse B16 cells by MTT assay. The T1-weighed magnetic resonance images were measured by a 3.0 T Sigma scanner. The morphologies of the CSNPs and Gd-CSNPs were spherical or ellipsoidal in shape. The mean sizes of the CSNPs and Gd-CSNPs were 110.9 +/- 6.8 nm and 153.0 +/- 7.5 nm, respectively. The zeta potentials of the CSNPs and Gd-CSNPs were 22.30 +/- 0.77 mV and 13.91 +/- 4.26 mV, respectively. The relaxation rates of Gd-CSNPs and Magnevist were 7.509 mM(-1) x s(-1) and 3.052 mM(-1) x s(-1), respectively. The Gd-CSNPs exhibited high T1 relaxivity and no obvious cytotoxicity was observed under the experimental concentrations in mouse B16 melanoma cells. These results indicated that the Gd-CSNPs had great potential as MRI contrast agents for the early diagnosis of tumor. PMID:23802417

Zhang, Li; Liu, Yongjun; Yu, Dexin; Zhangl, Na

2013-05-01

2

Gadolinium-loaded chitosan nanoparticles for neutron-capture therapy: Influence of micrometric properties of the nanoparticles on tumor-killing effect.  

PubMed

As a nanoparticulate device for controlled delivery of Gd in NCT, the authors have developed gadolinium-loaded chitosan nanoparticles (Gd-nanoCPs). In the present study, influence of micrometric properties such as particle size, particle-surface charge and Gd content of Gd-nanoCPs on tumor-killing effect by Gd-NCT was investigated with Gd-nanoCPs. Two types of Gd-nanoCPs with different mean particle size, zeta potential and Gd-content (Gd-nanoCP-400; 391nm, 28mV, 9wt% and Gd-nanoCP-200; 214nm, 19mV, 24wt%) could be prepared by using chitosans with different molecular weights. Gd-nanoCPs incorporating 1.2mg of natural Gd were injected intratumorally once or twice to mice subcutaneously-bearing B16F10 melanoma. Eight hours after the last administration, thermal neutron was irradiated to tumor region of the mice. Remarkable tumor-growth was observed in both hot and cold control groups. In contrast, Gd-NCT groups showed significant tumor-growth suppression effect, though their efficacy was found to depend on the micrometric properties of Gd-nanoCPs. In particular, the Gd-nanoCP-200 exhibited stronger tumor-killing effect than the Gd-nanoCP-400 at the same Gd dose and it was still similar to Gd-nanoCP-400 in tumor-growth suppressing effect even at the half of Gd dose of Gd-nanoCP-400. This significance in tumor-killing effect would be ascribed from a higher Gd retention in the tumor tissue and an improved distribution of Gd with intratumorally administered Gd-nanoCP-200. Indeed, the Gd concentration in tumor tissue at the time corresponding to the onset of thermal neutron irradiation was determined to be significantly higher in Gd-nanoCP-200, compared with Gd-nanoCP-400. These results demonstrated that appropriate modification of Gd-nanoCPs in micrometric properties would be an effective way to improve the retention of Gd in the tumor tissue after intratumoral injection, leading to the enhanced tumor-killing effect in Gd-NCT. PMID:24462286

Ichikawa, Hideki; Uneme, Takeshi; Andoh, Tooru; Arita, Yuya; Fujimoto, Takuya; Suzuki, Minoru; Sakurai, Yoshinori; Shinto, Hiroyuki; Fukasawa, Tomonori; Fujii, Fumihiko; Fukumori, Yoshinobu

2014-06-01

3

Novel chitosan coated magnetic nanocarriers for the targeted Diclofenac delivery.  

PubMed

New magnetic devices consisting of magnetite functionalized with oleic acid and chitosan have been synthesized and employed to the loading of Diclofenac as potential tool for treatment of targeted inflammatory diseases. Magnetic loaded and un-loaded nanoparticles have been thoroughly characterized by infrared spectroscopy, transmission electron microscopy, determination of hydrodynamic diameter by Dynamic light scattering and zeta potential measurements at different pH conditions. A study of the release of Diclofenac has been performed in vitro and available mathematical models have been used to determine the release kinetic. Both properties and release data reveal that this nanomagnetic platform would be suitable for in vivo assays. PMID:24734550

Agotegaray, Mariela; Palma, Santiago; Lassalle, Verónica

2014-05-01

4

Galactosylated chitosan nanoparticles for hepatocyte-targeted delivery of oridonin.  

PubMed

In this study, oridonin-loaded nanoparticles coated with galactosylated chitosan (ORI-GC-NP) were prepared for tumor targeting and their characteristics were evaluated for the morphologies, particle size and zeta potential. Oridonin-loaded nanoparticles (ORI-NP) without galactosylated chitosan were prepared as a control. The entrapment efficiency of ORI-GC-NP and ORI-NP were 72.15% and 85.31%, respectively. The in vitro drug release behavior from nanoparticles displayed biphasic drug release pattern with initial burst release and consequently sustained release. Next, the pharmacokinetics and tissue distribution of ORI-GC-NP, ORI-NP and ORI solution were carried out. Pharmacokinetic analysis showed that ORI-GC-NP and ORI-NP could prolong the drug plasma levels compared with ORI solution. Meanwhile, the distribution of ORI-GC-NP to liver was higher than that of ORI-NP and free drug. In conclusion, ORI-GC-NP, as a promising intravenous drug delivery system for ORI, could be developed as an alternative to the conventional ORI preparations. PMID:22732673

Zheng, Dandan; Duan, Cunxian; Zhang, Dianrui; Jia, Lejiao; Liu, Guangpu; Liu, Yue; Wang, Feihu; Li, Caiyun; Guo, Hejian; Zhang, Qiang

2012-10-15

5

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

Microsoft Academic Search

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

Baoyan Wu; Zhongmin Ou; Da Xing

2009-01-01

6

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

7

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

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.

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

2012-01-01

9

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

PubMed Central

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

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

2011-01-01

10

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

PubMed

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 microM. Notably, localization of nanoparticles in skin and hepatic tissue was significantly less than in tumor tissue, therefore photosensitivity and hepatotoxicity can be attenuated. PMID:19420486

Sun, Yun; Chen, Zhi-Long; Yang, Xiao-Xia; Huang, Peng; Zhou, Xin-Ping; Du, Xiao-Xia

2009-04-01

11

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

12

Chitosan-g-poly(N-isopropylacrylamide) based nanogels for tumor extracellular targeting.  

PubMed

The principle objective of this research was to develop and characterize pH-responsive and biocompatible nanogels as a tumor-targeting drug delivery system. The nanogels were self-assembled from chitosan-based copolymers, chitosan-graft-poly(N-isopropylacrylamide) (CS-g-PNIPAm). The copolymers were synthesized via free radical copolymerization and characterized for their chemical structure by FT-IR and (1)H NMR. These copolymers could be efficiently loaded with oridonin (ORI) and the characteristics of ORI-loaded nanogels were evaluated. Drug release researches indicated that the ORI-loaded nanogels displayed pH-dependent release behaviors. Based on MTT assay and cellular morphological analysis, the anti-tumor activity of ORI-loaded nanogels was higher at pH 6.5 than at pH 7.4. In conclusion, the obtained nanogels appeared to be of great promise in tumor extracellular pH targeting for ORI. PMID:21356283

Duan, Cunxian; Zhang, Dianrui; Wang, Feihu; Zheng, Dandan; Jia, Lejiao; Feng, Feifei; Liu, Yue; Wang, Yancai; Tian, Keli; Wang, Fengshan; Zhang, Qiang

2011-05-16

13

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

14

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.

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

2014-01-01

15

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

PubMed

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

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

2013-07-01

16

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

17

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

PubMed Central

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

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

2012-01-01

18

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

PubMed

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

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

2014-08-01

19

Glycol chitosan-based nanogel as a potential targetable carrier for siRNA.  

PubMed

A self-assembled glycol chitosan nanogel (GC) is synthesized by chemically grafting hydrophobic chains onto a polysaccharide, which is comprehensively characterized. The obtained macromolecular micelle is decorated with folate-conjugated poly(ethylene glycol) (PEG) (GCFA). An average size distribution of 250 and 200?nm is observed, respectively for the GC and GCFA nanogels. Differential cell localization is observed on incubating the materials with HeLa cells. Whereas the GC nanogel is detected on the cell surface, GCFA is localized in the cytoplasm. The cell viability is not compromised by the nanogels. Interestingly, GC nanogel is poorly internalized by bone marrow derived macrophages (BMDMs), and GCFA is not phagocytosed. Given its ability to complex siRNA, the targetable GC nanogel can be a promising vehicle for siRNA delivery. PMID:23996912

Pereira, Paula; Morgado, Daniela; Crepet, Agnès; David, Laurent; Gama, Francisco M

2013-10-01

20

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

21

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

22

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

23

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

24

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

Microsoft Academic Search

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

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

2010-01-01

25

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

PubMed Central

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

2011-01-01

26

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

PubMed Central

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

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

2013-01-01

27

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

PubMed Central

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

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

2011-01-01

28

Galactosylated chitosan oligosaccharide nanoparticles for hepatocellular carcinoma cell-targeted delivery of adenosine triphosphate.  

PubMed

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

29

Efficient pH dependent drug delivery to target cancer cells by gold nanoparticles capped with carboxymethyl chitosan.  

PubMed

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

30

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.

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

31

Bufalin loaded biotinylated chitosan nanoparticles: An efficient drug delivery system for targeted chemotherapy against breast carcinoma.  

PubMed

Bufalin is a traditional oriental medicine which is known to induce apoptosis in many tumor cells, and it is thus considered as a new anticancer therapeutic. By now, most of the studies of bufalin are in vitro, however in vivo evaluations of its therapeutic efficacy are less and are in great demand for its development toward anticancer drug. One of the problems probably hampering the development of bufalin is the lack of tumor selectivity, which may reduce the therapeutic effect as well as showing side effects. To overcome this drawback, in this study, we designed a tumor-targeted drug delivery system of bufalin based on enhanced permeability and retention (EPR) effect, by using biotinylated chitosan, resulting in bufalin encapsulating nanoparticles (Bu-BCS-NPs) with mean hydrodynamic size of 171.6nm, as evidenced by dynamic light scattering and transmission electron microscope. Bu-BCS-NPs showed a relative slow and almost linear release of bufalin, and about 36.8% of bufalin was released in 24h when dissolved in sodium phosphate buffer. Compared to native bufalin, Bu-BCS-NPs exhibited a stronger cytotoxicity against breast cancer MCF-7 cells (IC50 of 0.582?g/ml vs 1.896?g/ml of native bufalin). Similar results were also obtained in intracellular reactive oxygen species production, apoptosis induction, and decrease in mitochondria membrane potential. These results may contribute to the rapid intracellular uptake of nanoparticles, partly benefiting from the highly expressed biotin receptors in tumor cells. In vivo studies using MCF-7 tumor models in nude mice confirmed the remarkable therapeutic effect of Bu-BCS-NPs. These findings suggest the potential of Bu-BCS-NPs as an anticancer drug with tumor targeting property. PMID:24846793

Tian, Xin; Yin, Hongzhuan; Zhang, Shichen; Luo, Ying; Xu, Kai; Ma, Ping; Sui, Chengguang; Meng, Fandong; Liu, Yunpeng; Jiang, Youhong; Fang, Jun

2014-08-01

32

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

PubMed Central

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

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

2012-01-01

33

Development of chitosan oligosaccharide-modified gold nanorods for in vivo targeted delivery and noninvasive imaging by NIR irradiation.  

PubMed

In the present study, we demonstrate the synthesis and applications of multifunctional gold nanorod-based probes for specific targeting and noninvasive imaging based on localized heating generated by gold nanorods after NIR irradiation. The structural design of the probe consists of MUA (11-mercaptoundecanoic acid)-capped gold nanorods covalently linked with low-molecular-weight chitosan oligosaccharide (M(w) ~5000) via carbodiimide (EDC) coupling agent. This surface modification is performed for complete replacement of toxic CTAB (hexadecyltrimethyl-ammonium chloride) and acid-responsive delivery of gold nanorods in acidic environment as known to be present at tumor surrounding areas. The resulting chitosan oligosaccharide-modified gold nanorods (CO-GNRs) were further conjugated with tumor targeting monoclonal antibody against EGFR (epidermal growth factor receptor) to provide localized targeting functionality owing to the overexpression of EGFR in human oral adenosquamous carcinoma cell line CAL 27. Initial in vitro and in vivo toxicity assessments indicated that CO-GNRs did not induce any significant toxicity and are thus suitable for biological applications. Furthermore, selective targeting and accumulation of CO-GNRs were observed in vitro via two-photon luminescence imaging studies in CAL 27, which was also observed through in vivo targeting studies performed via NIR (near-infrared) laser irradiation in CAL 27 xenografts of BALB/c nude mice. Hence, the CO-GNRs that we have developed are biocompatible and nontoxic and can be a potential candidate for in vivo targeted delivery, noninvasive imaging based on localized hyperthermia, and photothermal-related therapies. PMID:23030814

Charan, Shobhit; Sanjiv, Kumar; Singh, Narendra; Chien, Fan-Ching; Chen, Yi-Fan; Nergui, Navchtsetseg Navchaa; Huang, Shih-Hsin; Kuo, Chiung Wen; Lee, Te-Chang; Chen, Peilin

2012-11-21

34

Properties and evaluation of quaternized chitosan/lipid cation polymeric liposomes for cancer-targeted gene delivery.  

PubMed

Development of high-stability and efficient nonviral vectors with low cytoxicity is important for targeted tumor gene therapy. In this study, cationic polymeric liposomes (CPLs), with similar lipid bilayer structure and high thermal stability, were prepared from polymeric surfactants of quaternized (carboxymethyl)chitosan with different carbon chains (dodecyl, tetradecyl, hexadecyl, and octadecyl). By comparing different factors that influence gene delivery, tetradecyl-quaternized (carboxymethy)chitosan (TQCMC) CPLs, with suitable size (184.4 ± 17.1 nm), ? potentials (27.5 ± 4.9 mV), and productivity for synthesis TQCMC (weight yield 13.1%), were selected for gene transfection evaluation in various cancer cell lines. Although TQCMC CPLs have lower gene transfection efficiency compared with cationic liposomes (Lipofectamine 2000) in vitro, they displayed higher reporter gene delivery ability for cancer tissues (bearing U87 and SMMC-7721 tumors) in vivo after intravenous injection. TQCMC CPLs also have lower cell cytotoxicity and lower cytokine production or liver injury for BALB/c mice. We conclude that the CPLs are promising gene delivery systems that may be used to target various cancers. PMID:23763489

Liang, Xiaofei; Li, Xiaoyu; Chang, Jin; Duan, Yourong; Li, Zonghai

2013-07-01

35

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

PubMed

Hydrogels are widely used in drug delivery systems because they can control the release and thereby enhance the efficiency of locally delivered bioactive molecules such as therapeutic drugs, proteins, or genes. For gene delivery, localized release of plasmid DNA or polymer/DNA complexes can transfect cells and produce sustained protein production. We tested the galactosylated chitosan-graft-polyethylenimine (GC-g-PEI)/DNA complexes-loaded poly(organophosphazene) thermosensitive biodegradable hydrogel as a hepatocyte targeting gene delivery system. The poly(organophosphazene) hydrogel loaded with GC-g-PEI/DNA complexes showed low cytotoxicity and higher transfection efficiency than PEI/DNA complexes, as well as good hepatocyte specificity in vitro and in vivo. Our results indicate that poly(organophosphazene) hydrogels loaded with GC-g-PEI/DNA complexes may be a safe and efficient hepatocyte targeting gene delivery system. PMID:20422364

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

2010-04-01

36

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

37

Chitosan-Graft-Polyethylenimine/DNA Nanoparticles as Novel Non-Viral Gene Delivery Vectors Targeting Osteoarthritis  

PubMed Central

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.

Lv, Lulu; Zhao, Huiqing

2014-01-01

38

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

PubMed Central

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

Wang, Hao; Xu, Yongdong; Zhou, Xiao

2014-01-01

39

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

PubMed Central

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

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

2012-01-01

40

Development of Both Methotrexate and Mitomycin C Loaded PEGylated Chitosan Nanoparticles for Targeted Drug Codelivery and Synergistic Anticancer Effect.  

PubMed

Codelivery of multiple drugs with one kind of drug carriers provided a promising strategy to suppress the drug resistance and achieve the synergistic therapeutic effect in cancer treatment. In this paper, we successfully developed both methotrexate (MTX) and mitomycin C (MMC) loaded PEGylated chitosan nanoparticles (CS-NPs) as drug delivery systems, in which MTX, as a folic acid analogue, was also employed as a tumor-targeting ligand. The new drug delivery systems can coordinate the early phase targeting effect with the late-phase anticancer effect. The (MTX+MMC)-PEG-CS-NPs possessed nanoscaled particle size, narrow particle size distribution, and appropriate multiple drug loading content and simultaneously sustained drug release. In vitro cell viability tests indicated that the (MTX+MMC)-PEG-CS-NPs exhibited concentration- and time-dependent cytotoxicity. Moreover, in vitro cellular uptake suggested that the (MTX+MMC)-PEG-CS-NPs could be efficiently taken up by cancer cells by FA receptor-mediated endocytosis. On the other hand, the (MTX+MMC)-PEG-CS-NPs can codelivery MTX and MMC to not only achieve the high accumulation at the tumor site but also more efficiently suppress the tumor cells growth than the delivery of either drug alone, indicating a synergistic effect. In fact, the codelivery of two anticancer drugs with distinct functions and different anticancer mechanisms was key to opening the door to their targeted drug delivery and synergistic anticancer effect. Therefore, the (MTX+MMC)-PEG-CS-NPs as targeted drug codelivery systems might have important potential in clinical implications for combination cancer chemotherapy. PMID:24977925

Jia, Mengmeng; Li, Yang; Yang, Xiangrui; Huang, Yuancan; Wu, Hongjie; Huang, Yu; Lin, Jinyan; Li, Yanxiu; Hou, Zhenqing; Zhang, Qiqing

2014-07-23

41

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

PubMed

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

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

2013-08-01

42

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

PubMed Central

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

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

2012-01-01

43

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

44

Magnetic Resonance Visualization of Tumor Angiogenesis by Targeting Neural Cell Adhesion Molecules with the Highly Sensitive Gadolinium-Loaded Apoferritin Probe  

Microsoft Academic Search

Tumor vessel imaging could be useful in identifying angio- genic blood vessels as well as being a potential predictive marker of antiangiogenic treatment response. We recently reported the expression of the neural cell adhesion molecule (NCAM) in the immature and tumor endothelial cell (TEC) lining vessels of human carcinomas. Exploiting an in vivo model of human tumor angiogenesis obtained by

Simonetta Geninatti Crich; Benedetta Bussolati; Lorenzo Tei; Cristina Grange; Giovanna Esposito; Stefania Lanzardo; Giovanni Camussi; Silvio Aime

2006-01-01

45

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

46

Characterization of folate-chitosan-DNA nanoparticles for gene therapy  

Microsoft Academic Search

Gene therapy using polymers such as chitosan shows good biocompatibility, but low transfection efficiency. The mechanism of folic acid (FA) uptake by cells to promote targeting and internalization could improve transfection rates. The objective of this study was to synthesize and characterize FA-chitosan-DNA nanoparticles and evaluate their cytotoxicity in vitro. Chitosan-DNA and FA-Chitosan-DNA nanoparticles were prepared using reductive amidation and

Sania Mansouri; Yan Cuie; Francoise Winnik; Qin Shi; Patrick Lavigne; Mohamed Benderdour; Eric Beaumont; Julio C. Fernandes

2006-01-01

47

Encapsulation of paclitaxel into lauric acid-O-carboxymethyl chitosan-transferrin micelles for hydrophobic drug delivery and site-specific targeted delivery.  

PubMed

Transferrin/PEG/O-carboxymethyl chitosan/fatty acid/paclitaxel (TPOCFP) micelles were tested for suitability as a drug carrier characterized by low cytotoxicity, sustained release, high cellular uptake, and site-specific targeted delivery of hydrophobic drugs. Characterization, drug content, encapsulation efficiency, and in vitro drug release were investigated. When the feeding amount of paclitaxel (PTX) was increased, the drug content increased, but loading efficiency decreased. TPOCFP micelles had a spherical shape, with a particle size of approximately 140-649 nm. In vitro cell cytotoxicity and hemolysis assays were conducted to confirm the safety of the micelles. Anticancer activity and confocal laser scanning microscopy (CLSM) were used to confirm the targeting efficiency of target ligand-modified TPOCFP micelles. Anticancer activity and CLSM results clearly demonstrated that transferrin-modified TPOCFP micelles were quickly taken up by the cell. The endocytic pathway of TPOCFP micelles was analyzed by flow cytometry, revealing transfection via receptor-mediated endocytosis. These results suggest that PTX-encapsulated TPOCFP micelles may be used as an effective cancer-targeting drug delivery system for chemotherapy. PMID:24076228

Nam, Joung-Pyo; Park, Seong-Cheol; Kim, Tae-Hun; Jang, Jae-Yeang; Choi, Changyong; Jang, Mi-Kyeong; Nah, Jae-Woon

2013-11-30

48

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

PubMed

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

Li, Hongmei; Li, Zhen; Zhao, Jin; Tang, Baoqiang; Chen, Yanhong; Hu, Yikun; He, Zhengda; Wang, Yue

2014-01-01

49

Carboxyalkylation of chitosan in the gel state.  

PubMed

This study presents a new approach for direct carboxyalkylation of chitosan in the gel state by using aza-Michael addition and substitution reactions. Various reagents were applied including acrylic and crotonic acids, and ?-, ?-, ?-, ?-, and ?-halocarboxylic acids. The reaction of chitosan with ?- and ?-halocarboxylic acids showed no target product formation either in solution or in the gel state. In the case of acrylic, crotonic, ?- and ?-halocarboxylic acids, the reaction performed in the gel state (concentration of chitosan 20-40%) shows higher degree of substitution at lower reaction time and temperature than in diluted solutions (concentration of chitosan 0.5-2%). The results were discussed in terms of kinetics of the target and side reactions. (1)H and (13)C NMR confirmed that in all cases the carboxyalkylation of chitosan proceeds exclusively at the amino groups. PMID:22840055

Skorik, Yury A; Pestov, Alexander V; Kodess, Mikhail I; Yatluk, Yury G

2012-10-01

50

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

PubMed Central

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

Shrestha, Annie; Hamblin, Michael R.

2012-01-01

51

Characterization of a conjugate between Rose Bengal and chitosan for targeted antibiofilm and tissue stabilization effects as a potential treatment of infected dentin.  

PubMed

Bacterial biofilms and dentin structural changes are some of the major challenges in the management of infected dentin tissue. This study characterized a photosensitizer-conjugated chitosan with enhanced photodynamic efficacy against dental biofilms, as well as the ability to reinforce the postinfected dentin matrix in order to improve its mechanical and chemical stability. Rose Bengal-conjugated chitosan (CSRB) was synthesized using a chemical cross-linking method and characterized for photophysical, photobiological, and cytotoxicity properties. Its potential as an antibacterial and matrix-reinforcing agent on dentin collagen was also evaluated. Enterococcus faecalis as planktonic and in vitro biofilms was treated with CSRB and photodynamically activated with 5 to 60 J/cm(2) green light. Dentin collagen was used for the CSRB cross-linking experiments and evaluated for chemical changes, resistance to enzymatic degradation, and mechanical properties. CSRB was a photosensitizer with efficient singlet oxygen yield. In vitro photoactivation gave higher fibroblast cell survival than did RB alone. CSRB showed significant antibiofilm photoinactivation (P < 0.01). The CSRB-cross-linked dentin collagen showed higher resistance to collagenase degradation and superior mechanical properties (P < 0.05). In summary, the photoactivated CSRB particles synthesized in this study may be a synergistic multifunctional treatment approach with lower cytotoxicity and effective antibiofilm activity as well as the ability to reinforce the dentin collagen to enhance resistance to degradation and improve mechanical properties. This may be a targeted treatment strategy to deal with infected dentin hard tissues in a clinical scenario, where both disinfection and structural integrity need to be addressed concomitantly. PMID:22777042

Shrestha, Annie; Hamblin, Michael R; Kishen, Anil

2012-09-01

52

In vivo studies of octreotide-modified N-octyl-O, N-carboxymethyl chitosan micelles loaded with doxorubicin for tumor-targeted delivery.  

PubMed

Octreotide (OCT) was recently found to have a high binding affinity for the somatostatin receptor expressed on tumor cells. In this study, OCT-polyethylene glycol-stearic acid (OCT-Phe-PEG-A) was used as a targeting molecule for N-octyl-O, N-carboxymethyl chitosan (OCC) micelles loaded with doxorubicin (DOX). For in vivo fluorescence imaging, the fluorescent probe Cyanine 7 (Cy7) was successfully loaded into OCC micelles with or without OCT modification (Cy7-OCC, Cy7-OCC-OCT), and their physicochemical properties were compared with DOX-loaded micelles (DOX-OCC and DOX-OCC-OCT). All micelles were less than 120 nm with spherical shape and zeta potential of around -30 mV. Enhanced tumor-targeting capacity of OCC-OCT micelles was observed in BALB/c nude mice bearing MCF-7 cancer xenografts as compared with the OCC micelles. Moreover, pharmacodynamic studies demonstrated that DOX-OCC-OCT presented a strongest inhibition of tumor growth and lowest systemic toxicity compared with the DOX solution and DOX-OCC micelles. All the results indicated that OCC-OCT micelles might be a promising tumor-targeting carrier for cancer therapy. PMID:23073894

Zou, Aifeng; Chen, Yan; Huo, Meirong; Wang, Jing; Zhang, Yong; Zhou, Jianping; Zhang, Qiang

2013-01-01

53

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.

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

54

Chitosan compositions  

US Patent & Trademark Office Database

Compositions comprising chitosan in the form of a network of nano-sized fibres. There is also provided a process for making such compositions. The compositions have improved solubility and activity. The compositions are useful in hair care, skin care, odour control, wound care, blood management, sanitary compositions, oral care, film formation, hard surface treatment, fabric treatment, release of hydrophobic or hydrophilic materials, plant care, water purification and drug delivery.

2003-10-28

55

M cell-targeting strategy facilitates mucosal immune response and enhances protection against CVB3-induced viral myocarditis elicited by chitosan-DNA vaccine.  

PubMed

Efficient delivery of antigen to mucosal associated lymphoid tissue is a first and critical step for successful induction of mucosal immunity by vaccines. Considering its potential transcytotic capability, M cell has become a more and more attractive target for mucosal vaccines. In this research, we designed an M cell-targeting strategy by which mucosal delivery system chitosan (CS) was endowed with M cell-targeting ability via conjugating with a CPE30 peptide, C terminal 30 amino acids of clostridium perfringens enterotoxin (CPE), and then evaluated its immune-enhancing ability in the context of coxsackievirus B3 (CVB3)-specific mucosal vaccine consisting of CS and a plasmid encoding CVB3 predominant antigen VP1. It had shown that similar to CS-pVP1, M cell-targeting CPE30-CS-pVP1 vaccine appeared a uniform spherical shape with about 300nm diameter and +22mV zeta potential, and could efficiently protect DNA from DNase I digestion. Mice were orally immunized with 4 doses of CPE30-CS-pVP1 containing 50?g pVP1 at 2-week intervals and challenged with CVB3 4 weeks after the last immunization. Compared with CS-pVP1 vaccine, CPE30-CS-pVP1 vaccine had no obvious impact on CVB3-specific serum IgG level and splenic T cell immune responses, but significantly increased specific fecal SIgA level and augmented mucosal T cell immune responses. Consequently, much milder myocarditis and lower viral load were witnessed in CPE30-CS-pVP1 immunized group. The enhanced immunogenicity and immunoprotection were associated with the M cell-targeting ability of CPE30-CS-pVP1 which improved its mucosal uptake and transcytosis. Our findings indicated that CPE30-CS-pVP1 may represent a novel prophylactic vaccine against CVB3-induced myocarditis, and this M cell-targeting strategy indeed could be applied as a promising and universal platform for mucosal vaccine development. PMID:24958702

Ye, Ting; Yue, Yan; Fan, Xiangmei; Dong, Chunsheng; Xu, Wei; Xiong, Sidong

2014-07-31

56

Low-density lipoprotein-coupled N-succinyl chitosan nanoparticles co-delivering siRNA and doxorubicin for hepatocyte-targeted therapy.  

PubMed

Developing safe and effective carriers of small interference RNA (siRNA) is a significant demand for the systemic delivery of siRNA. In this study, low-density lipoprotein (LDL) was isolated from human plasma and loaded with cholesterol-conjugated siRNA to silence the multidrug resistant gene of tumors. Chol-siRNA/LDL-coupled N-succinyl chitosan nanoparticles loaded with doxorubicin (Dox-siRNA/LDL-SCS-NPs) were then prepared and characterised. The Dox-siRNA/LDL-SCS-NPs had average particle size of 206.4 ± 9.2 nm, entrapment efficiency of 71.06% ± 1.42%, and drug-loading amount of 12.35% ± 0.87%. In vitro antitumor activity revealed that cell growth was significantly inhibited. The accumulation of Dox by fluorescence microscopy and flow cytometry showed that LDL-coupled nanoparticles were more easily taken up than Dox-SCS-NPs. Results of confocal microscopy and reverse transcription-PCR revealed the highly efficient uptake of siRNA and the decrease in mdr1 mRNA expression. LDL-coupled nanoparticles protected siRNA from macrophage phagocytosis by dynamic observation using live cell station. In vivo tumor-targeting suggested that Cy7-labelled Dox-LDL-SCS-NPs were markedly accumulated in an analyzed in situ liver tumor model. Results indicated that LDL-SCS-NPs were effective tumor-targeting vectors and that the preparation form may provide a new strategy for co-delivering siRNA and antitumor drugs. PMID:24768047

Zhu, Qiao-Ling; Zhou, Yi; Guan, Min; Zhou, Xiao-Feng; Yang, Shu-di; Liu, Yang; Chen, Wei-Liang; Zhang, Chun-Ge; Yuan, Zhi-Qiang; Liu, Chun; Zhu, Ai-Jun; Zhang, Xue-Nong

2014-07-01

57

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

PubMed

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

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

1999-06-01

58

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

59

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.

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

60

Effect of HPMC - E15 LV premium Polymer on Release Profile and Compression Characteristics of Chitosan/ Pectin Colon Targeted Mesalamine Matrix Tablets and in vitro Study on Effect of pH Impact on the Drug Release Profile.  

PubMed

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

Newton, A M J; Lakshmanan, Prabakaran

2014-04-01

61

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

62

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

PubMed

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

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

2012-11-01

63

Chitosan microspheres in novel drug delivery systems.  

PubMed

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

Mitra, Analava; Dey, Baishakhi

2011-07-01

64

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

65

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

66

Production of Chitosan by fungi  

Microsoft Academic Search

Chitosan is a novel biopolymer with numerous industrial, food, and biomedical applications. Our studies examined the production of chitosan from mycelia of Absidia coerulea, Mucor rouxii, Gongronella butieri, Phvcomyces blakesleeanus and Absidia blakesleeana. In batch culture, strains were screened to determine the fastest growing and greatest chitosan?yielding fungi. Optimum chitosan yields were observed for most cultures at 21°and 26°C in

Kishore D. Rane; Dallas G. Hoover

1993-01-01

67

Chitosan and radiation chemistry  

Microsoft Academic Search

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,

Andrzej G. Chmielewski

2010-01-01

68

Pharmaceutical applications of chitosan  

Microsoft Academic Search

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

Valérie Dodane; Vinod D Vilivalam

1998-01-01

69

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

PubMed

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

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

2012-09-01

70

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

71

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

PubMed Central

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

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

2012-01-01

72

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

73

Structural features of sulfated chitosans  

Microsoft Academic Search

Chitosan sulfates prepared by different methods were analyzed by 13C NMR spectroscopy. It was shown that the sulfation conditions of chitosan essentially affect the position and degree of substitution with sulfate in derivatives of chitosan. Sulfated products obtained under homogeneous conditions are characterized by more heterogeneity and they have to be considered as copolymers of chitosan 6-O-monosulfate and 3,6-O-disulfate, whereas

A. Gamzazade; A. Sklyar; S. Nasibov; I. Sushkov; A. Shashkov; Yu. Knirel

1997-01-01

74

Enzymatic degradation of thiolated chitosan.  

PubMed

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

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

2013-10-01

75

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

76

[Coliphages inactivation using chitosan derivatives].  

PubMed

The effect of chitosan fragments with different degrees of polymerization and the chemical derivatives of chitosan differing in the number of amino groups and total molecule charge on phages T2, T4, and T7 was studied. The interaction of chitosan with bacteriophage particles inactivated them to the extent dependent on the chemical properties of chitosan and its concentration. Phage T2 was found to be most susceptible to inactivation by chitosan. The polycationic nature of chitosan plays an important role in the inactivation of phages. It is assumed that the abnormal rearrangement of the basal plate of phages, the loss of long tail fibers, and probably, modification of the receptor-recognizing phage proteins may be responsible for the inactivation of coliphages by chitosan. PMID:10776628

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

2000-01-01

77

Chitosan in Plant Protection  

PubMed Central

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

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

2010-01-01

78

Ellagic acid encapsulated chitosan nanoparticles as anti-hemorrhagic agent.  

PubMed

Ellagic acid, a naturally occurring polyphenol was encapsulated in chitosan particles prepared by ionotropic gelation and characterized for its physicochemical properties. A maximum encapsulation efficiency of 49% was achieved. The blood clotting time and clot retraction time were calculated for different concentrations of ellagic acid, chitosan and ellagic acid-encapsulated chitosan. A reduction of 34% in the clot time and 16.4% in the retraction time was observed in ellagic acid-encapsulated chitosan when compared with free ellagic acid at concentrations as low as 0.1mg/mL. The physical blend in comparison to free ellagic acid displayed a reduction of 13.8% and 4.6% in the clotting time and retraction time respectively under similar conditions. This suggests that the encapsulation of ellagic acid favors thrombosis due to synergistic action of chitosan and ellagic acid on same molecular targets. This study demonstrates the potential of ellagic acid-chitosan system as an effective anti-hemorrhagic system. PMID:25037345

Gopalakrishnan, Lalitha; Ramana, Lakshmi Narashimhan; Sethuraman, Swaminathan; Krishnan, Uma Maheswari

2014-10-13

79

Multiple effects of chitosan on plant systems: solid science or hype.  

PubMed

Chitosan, a naturally occurring polymer, became available in the 1980s in industrial quantities enabling it to be tested as an agricultural chemical. A usual procedure for developing agricultural chemicals starts by testing a number of different chemically synthesized molecules on a targeted biological system. Alternately, chitosan has been investigated as a single natural molecule assayed with numerous biological systems. This report describes the unique properties of the molecule and its oligomers, primarily in plant defense, additionally in yield increase, induction of cell death and stomatal closing. The plant plasma membrane and nuclear chromatin have been proposed as targets, though chitosan oligomers enter most regions of the cell. Subsequent changes occur in: cell membranes, chromatin, DNA, calcium, MAP kinase, oxidative burst, reactive oxygen species (ROS), callose, pathogenesis related (PR) genes/proteins, and phytoalexins. Chitosan oligomer mode(s) of action are proposed for different plant systems. Chitosan efficacy was based on documentation from published data. Attention was given to how chitosan, either applied externally or released by fungal inoculum, is transferred into plant cells and its subsequent action upon membrane and/or chromatin components. Within is a proposed scheme describing chitosan generation, signaling routes and mechanisms of defense gene activation. Examples of beneficial chitosan applications to major crop/food plants were included. PMID:23683928

Hadwiger, Lee A

2013-07-01

80

Intratumoral Immunotherapy of Established Solid Tumors with Chitosan/IL-12  

PubMed Central

Summary IL-12 is a potent antitumor cytokine that exhibits significant clinical toxicities following systemic administration. We hypothesized that intratumoral (i.t.) administration of IL-12 coformulated with the biodegradable polysaccharide chitosan could enhance the antitumor activity of IL-12 while limiting its systemic toxicity. Noninvasive imaging studies monitored local retention of IL-12, with and without chitosan coformulation, following i.t. injection. Antitumor efficacy of IL-12 alone and IL-12 coformulated with chitosan (chitosan/IL-12) was assessed in mice bearing established colorectal (MC32a) and pancreatic (Panc02) tumors. Additional studies involving depletion of immune cell subsets, tumor rechallenge, and CTL activity were designed to elucidate mechanisms of regression and tumor-specific immunity. Coformulation with chitosan increased local IL-12 retention from 1 to 2 days to 5 to 6 days. Weekly i.t. injections of IL-12 alone eradicated ? 10% of established MC32a and Panc02 tumors, while i.t. chitosan/IL-12 immunotherapy caused complete tumor regression in 80% to 100% of mice. Depletion of CD4+ or Gr-1+ cells had no impact on chitosan/IL-12-mediated tumor regression. However, CD8+ or NK cell depletion completely abrogated antitumor activity. I.t. chitosan/IL-12 immunotherapy generated systemic tumor-specific immunity, as > 80% of mice cured with i.t. chitosan/IL-12 immunotherapy were at least partially protected from tumor rechallenge. Furthermore, CTLs from spleens of cured mice lysed MC32a and gp70 peptide-loaded targets. Chitosan/IL-12 immunotherapy increased local retention of IL-12 in the tumor microenvironment, eradicated established, aggressive murine tumors, and generated systemic tumor-specific protective immunity. Chitosan/IL-12 is a well-tolerated, effective immunotherapy with considerable potential for clinical translation.

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

2012-01-01

81

Acid hydrolysis of chitosans  

Microsoft Academic Search

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

K. M. Vårum; M. H. Ottøy; O. Smidsrød

2001-01-01

82

Blood protein adsorption onto chitosan  

Microsoft Academic Search

Chitosan was recently indicated to enhance osteogenesis, improve wound healing but to activate the coagulation and the complement systems. In the present study approximately 10nm thick chitosan film were prepared on aminopropyltriethoxysilane (APTES) coated silicon. The surfaces were incubated in serum or plasma and subsequently in antibodies towards key complement and contact activation of coagulation proteins. The deposited amounts were

Johan Benesch; Pentti Tengvall

2002-01-01

83

Enzyme encapsulation on chitosan microbeads  

Microsoft Academic Search

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

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

1997-01-01

84

Radiation-induced changes in carboxymethylated chitosan  

Microsoft Academic Search

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 N2-saturated was 0.49, which showed CM-chitosan has high

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

2007-01-01

85

PERVAPORATION OF ETHANOL-WATER USING CHITOSAN CLAY COMPOSITE MEMBRANE  

Microsoft Academic Search

The pervaporation performance for the separation of ethanol-water azeotrope mixture was assessed by chitosan-clay composite membranes. Composite hydrophilic chitosan membrane was prepared from commercially available chitosan powder. The chitosan powder was dissolved using dilute acetic acid to produce chitosan solution. The chitosan solution was blended with small amount of clay and casted on a porous support which prepared from polysulfone

MOHD GHAZALI MOHD NAWAWI; AZIATUL NIZA SADIKIN; TAN GI GI

86

Heavy metals adsorption by novel EDTA-modified chitosan–silica hybrid materials  

Microsoft Academic Search

Novel adsorbents were synthesized by functionalizing chitosan–silica hybrid materials with (ethylenediaminetetraacetic acid) EDTA ligands. The synthesized adsorbents were found to combine the advantages of both silica gel (high surface area, porosity, rigid structure) and chitosan (surface functionality). The Adsorption potential of hybrid materials was investigated using Co(II), Ni(II), Cd(II), and Pb(II) as target metals by varying experimental conditions such as

Eveliina Repo; Jolanta K. Warcho?; Amit Bhatnagar; Mika Sillanpää

2011-01-01

87

Radiolysis of chitosan  

Microsoft Academic Search

The ?-radiolysis of solid chitosan was studied. The radiolysis products hydrogen and ammonia were determined by chromatography\\u000a and spectrophotometry (with Nessler’s reagent), respectively, and the amino groups were determined by potentiometic titration.\\u000a The radiation-chemical yields were found to be G\\u000a H\\u000a 2 = 2.0 ± 0.3; G\\u000a NH\\u000a 3 = 5.8 ± 0.4 and G\\u000a ?NH\\u000a 2 = 2.9 ±

K. Zelinska; A. G. Shostenko; S. Truszkowski

2009-01-01

88

Immune stimulating activity of two new chitosan containing adjuvant formulations.  

PubMed

Recombinant proteins have potential as both human and veterinary vaccine antigens, but they are often weakly immunogenic and immunization with recombinant proteins may not elicit a significant immune response that recognizes the native protein. This report describes the immune stimulating activity of two new adjuvant formulations, a zinc-chitosan particle formulation designed to bind to histidine tagged recombinant proteins; and an emulsion formulation containing chitosan. BALB/c mice vaccinated with formulations comprising recombinant beta-human chorionic gonadotropin (betahCG) and each adjuvant had prolonged high titer antibodies that recognized both the recombinant betahCG and native hCG. betahCG is an established target for immunocontraceptive vaccines and a potential target for tumor immunotherapy. Isotype analysis of these antibodies revealed an IgG1 response in mice immunized with zinc-chitosan particles and a mixed IgG1, IgG2a and IgG2b response with the emulsion. These chitosan based adjuvant formulations were effective in sensitizing mice and guinea pigs for antigen specific DTH responses, indicating that these adjuvants stimulate both B and T lymphocytes. The ability of these adjuvants to stimulate significant responses with a poorly immunogenic recombinant protein suggests that they may have potential in developing vaccines based on synthetic peptides and subunit antigens. PMID:11090719

Seferian, P G; Martinez, M L

2000-11-01

89

Target  

US Patent & Trademark Office Database

The present invention relates to an isolated target sequence. The target sequence is a splice variant of PDE5 called a PDE5a1, a component of which is presented as SEQ ID No 1. The identified target sequence of the present invention may be used to as a target to identify agents (such as modulators) useful in the prevention and/or treatment of a disease associated with scarring and/or fibrosis or to selectively identify smooth muscle cells and myofibroblasts and myoepithelial cells in samples of normal and diseased tissue from individuals.

2004-09-21

90

The effect of chitosan molecular weight on the properties of alginate\\/ chitosan microparticles containing prednisolone  

Microsoft Academic Search

Purpose : The aim of the present study was to investigate the effect of chitosan molecular weight on size, size distribution, release rate, mucoadhesive properties and electrostatic bonding of alginate\\/chitosan microparticles containing prednisolone Method s: Three mucoadhesive alginate\\/chitosan microparticle formulations, f1, f2 and f3, were prepared using low, medium and high chitosan molecular weight (MW) chitosan, respectively, by directly spraying

Soheila Honary; Maryam Maleki; M Karami

91

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

92

In vivo transfection study of chitosan-DNA-FAP-B nanoparticles as a new non viral vector for gene delivery to the lung.  

PubMed

Gene therapy targeted at the respiratory epithelium holds therapeutic potential for diseases such as cystic fibrosis and lung cancer. We recently reported that Chitosan-DNA-FAP-B nanoparticles are good candidates for targeted gene delivery to fibronectin molecules (FAP-B receptors) of lung epithelial cell membrane. In this study Chitosan-DNA-FAP-B nanoparticles were nebulized to mice using air jet nebulizer. The effect of nebulization on size, zeta potential and DNA binding ability of nanoparticles were studied. The level of gene expression in the mice lungs was evaluated. Nebulization did not affect the physicochemical properties of nanoparticles. Aerosol delivery of Chitosan-DNA-FAP-B nanoparticles resulted in 16-fold increase of gene expression in the mice lungs compared with Chitosan-DNA nanoparticles. This study suggested that Chitosan-FAP-B nanoparticle can be a promising carrier for targeted gene delivery to the lung. PMID:21979252

Mohammadi, Z; Dorkoosh, F A; Hosseinkhani, S; Gilani, K; Amini, T; Najafabadi, A Rouholamini; Tehrani, M Rafiee

2011-12-12

93

[The antiviral activity of chitosan (review)].  

PubMed

Data on the inhibitory effect of chitosan on viral infections in animals, plants, and microorganisms are reviewed. The effects of the physicochemical parameters and structure of chitosan on its antiviral activity are analyzed. Possible mechanisms of the inhibitory effect of chitosan on viral infections are discussed. PMID:11852567

Chirkov, S N

2002-01-01

94

Palladium sorption on glutaraldehyde-crosslinked chitosan  

Microsoft Academic Search

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

Montserrat Ruiz; Ana Maria Sastre; Eric Guibal

2000-01-01

95

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

96

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

97

Spinning of hydroalcoholic chitosan solutions.  

PubMed

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

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

2013-10-15

98

Erythrocytes load of low molecular weight chitosan nanoparticles as a potential vascular drug delivery system.  

PubMed

Low molecular weight (LMW) chitosan nanoparticles have attracted considerable attention as colloidal drug carriers, but when applied to intravascular drug delivery, they are easy to be removed from circulation by the reticuloendothelial system, which limits their applications as long-circulating or target-specific carriers. Erythrocytes have a long circulation time in the blood, but they are sometimes not suitable for loading and releasing of drug directly. The combination of LMW chitosan nanoparticles and erythrocytes that complement each other is a desirable strategy to develop a multifunctional drug carrier. In this study, monodisperse, LMW chitosan nanoparticles were prepared by ionic gelation technique and these nanoparticles were investigated with regard to their erythrocyte compatibility. Then the interactions between erythrocytes and fluorescence-labeled LMW chitosan nanoparticles were studied by confocal microscopy. The results of this study indicate that LMW chitosan nanoparticles show good compatibility with erythrocytes and they can be easily attached to the surface of erythrocyte membrane, suggesting that erythrocytes load of LMW chitosan nanoparticles can be served as a potential vascular drug delivery system. PMID:22469561

Fan, Wen; Yan, Wei; Xu, Zushun; Ni, Hong

2012-06-15

99

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

100

Polyelectrolyte complexes of chitosan: formation, properties and applications  

Microsoft Academic Search

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

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

2008-01-01

101

Chitosan Microparticles Prepared by the Simple Emulsification-Diffusion Method  

Microsoft Academic Search

Biodegradable chitosan microparticles were prepared by a water-in-oil emulsion solvent diffusion method without any surfactants. Aqueous chitosan solution and ethyl acetate were used as the water and oil phases, respectively. The chitosan microparticles; with spherical, deflated, and hollow shapes, could be fabricated from different chitosan concentrations. Chitosan microparticle matrices were sponge-like. The particle sizes increased with the chitosan concentration and

Nualchai Kotsaeng; Jesada Karnchanajindanun; Yodthong Baimark

2010-01-01

102

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

103

Chitosan microparticles for oral vaccination  

Microsoft Academic Search

Although oral vaccination has numerous advantages over parenteral injection, degradation of the vaccine in the gut and low uptake in the lymphoid tissue of the gastrointestinal tract still complicate the development of oral vaccines. In this study chitosan microparticles were prepared and characterized with respect to size, zeta potential, morphology and ovalbumin-loading and -release. Furthermore, the in vivo uptake of

I. M van der Lubben; J. C Verhoef; A. C van Aelst; G Borchard; H. E Junginger

2001-01-01

104

Chitosan structure in aqueous solution  

Microsoft Academic Search

Chitosans having three different degrees of acetylation ( DA) were studied in acid solution using the uranyl staining technique and electron microscopy. Strings of approximately spherical aggregates were seen. The aggregates were interpreted as micelle-like agglomerates formed by almost fully acetylated polysaccharide, interconnected by blocks of almost fully deacetylated polysaccharide stretched by electrostatic repulsion. These agglomerates include NH 3 +

V. I. Pedroni; P. C. Schulz; M. E. Gschaider; N. Andreucetti

2003-01-01

105

The synthesis and antioxidant activity of the Schiff bases of chitosan and carboxymethyl chitosan  

Microsoft Academic Search

Five kinds of Schiff bases of chitosan and carboxymethyl chitosan (CMCTS) have been prepared according to a previous method and the antioxidant activity was studied using an established system, such as superoxide and hydroxyl radical scavenging. Obvious differences between the Schiff bases of chitosan and CMCTS were observed, which might be related to contents of the active hydroxyl and amino

Zhanyong Guo; Ronge Xing; Song Liu; Huahua Yu; Pibo Wang; Cuiping Li; Pengcheng Li

2005-01-01

106

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.

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

2010-01-01

107

Radiation depolymerization of chitosan to prepare oligomers  

NASA Astrophysics Data System (ADS)

Radiation depolymerization of chitosan was carried out by gamma irradiation in the solid state. The radiation-chemical depolymerization yield of chitosan in the solid state, Gd, determined by gel permeation chromatography, is 0.9 for chitosan 10B and 1.8 for chitosan 8B. Low molecular weight chitosan/or oligochitosans were separated from a chitosan depolymerized by gamma radiation, using mixtures of methanol-water and acetone as the solvents. Due to the differences in solubility revealed upon radiolysis, extracts became subdivided into precipitates and soluble fractions. The biological effect of oligochitosan in each fraction was evaluated; the preliminary results indicated that the oligochitosan with overlineM w=2×10 4 inhibited the growth of fungi at 100 ppm and that with overlineM w=800 only enhanced the growth of the same typical fungi.

Hai, Le; Bang Diep, Tran; Nagasawa, Naotsugu; Yoshii, Fumio; Kume, Tamikazu

2003-08-01

108

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

109

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

PubMed Central

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.

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

2014-01-01

110

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

111

Fragmentation of Chitosan by Acids  

PubMed Central

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

Arul, Joseph; Charlet, Gerard

2013-01-01

112

Template synthesized chitosan nano test tubes for drug delivery applications  

NASA Astrophysics Data System (ADS)

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

Perry, Jillian L. Moulton

113

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

PubMed Central

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

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

2010-01-01

114

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

115

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

116

Biocompatibility of chitosan-coated iron oxide nanoparticles with osteoblast cells  

PubMed Central

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

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

2012-01-01

117

Herstellung von Chitosan und einige Anwendungen  

Microsoft Academic Search

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

Marcin Henryk Struszczyk

2001-01-01

118

Conductivity study of chitosan based nanocomposites  

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

119

Chitosan Polyelectrolyte Nanoparticles As Protein Delivery Systems  

Microsoft Academic Search

Nanoparticles with various formations were produced based on ionic gelation process between chitosan and tripolyphosphate (TPP) by using bovine serum albumin (BSA) as a model drug. Their average diameter was 300-700 nm with the examination of laser granularity analyzer. The morphologies were examined with optical microscope and TEM. FTIR was used to study the structure characterization between chitosan and TPP.

Nan Xing; Feng Tian; Shengjun Liu; Hong Liu; Changjun Liu; Jian Yang; Chunnian He

2009-01-01

120

Chitin and chitosan: Chemistry, properties and applications  

Microsoft Academic Search

Chitin and chitosan are considerably versatile and promising biomaterials. The deacetylated chitin derivative, chitosan is more useful and interesting bioactive polymer. Despite its biodegradability, it has many reactive amino side groups, which offer possibilities of chemical modifications, formation of a large variety of useful derivatives that are commercially available or can be made available via graft reactions and ionic interactions.

Pradip Kumar Dutta; Joydeep Dutta; V S Tripathi

121

Electrodeposition of composite hydroxyapatite–chitosan films  

Microsoft Academic Search

Hydroxyapatite (HA) powders were prepared by a chemical precipitation method and used for the fabrication of the HA–chitosan nanocomposite coatings. The proposed method for the coating fabrication is based on the electrochemical deposition of chitosan and electrophoretic deposition of HA. Cathodic deposits of various thicknesses in the range of up to 50?m were obtained on Pt and stainless steel foils,

Xin Pang; Igor Zhitomirsky

2005-01-01

122

Ultrathin Chitosan Films with Tailored Properties  

Microsoft Academic Search

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

Chris Murray; Oleg Stukalov; John Dutcher

2004-01-01

123

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

124

In Vivo Assessment of Chitosan/ ?-Glycerophosphate as a New Liquid Embolic Agent  

PubMed Central

Summary We sought to assess the feasibility of using thermosensitive chitosan/?-glycerophosphate for embolotherapy. The renal arteries in nine rabbits were embolized with chitosan/?-glycerophosphate. The animals were studied angiographically and sacrificed at one week (n = 3), four weeks (n = 3), and eight weeks (n = 3) after embolotherapy. Histology was obtained at these three time points. Delivery of chitosan/?-glycerophosphate was successful in all cases. Complete occlusion was achieved in all cases. No recanalization was observed in the follow-up angiograms. No untoward inflammatory reactions were observed in the target renal arteries and infarcted kidneys during the histological examinations. Our preliminary feasibility evaluation in rabbit renal arteries indicates that C/GP is a satisfactory embolization agent.

Wang, Y.; Xu, N.; Luo, Q.; Li, Y.; Sun, L.; Wang, H.; Xu, K.; Wang, B.; Zhen, Y.

2011-01-01

125

Properties of melt processed chitosan and aliphatic polyester blends  

Microsoft Academic Search

Chitosan was melt blended with poly-?-caprolactone (PCL), poly(butylene succinate) (PBS), poly(lactic acid) (PLA), poly(butylene terephthalate adipate) (PBTA), and poly(butylene succinate adipate) (PBSA). For the chitosan\\/PBS blend, the amount of chitosan was varied from 25% to 70% by weight. The remaining polyesters had 50% of chitosan by weight. Addition of chitosan to PBS or PBSA tends to depress the melting temperature

V. M. Correlo; L. F. Boesel; M. Bhattacharya; J. F. Mano; N. M. Neves; R. L. Reis

2005-01-01

126

Hydrated salts as both solvent and plasticizer for chitosan  

Microsoft Academic Search

Some hydrated salts were determined to act as both solvent and plasticizer for chitosan. Chitosan was dissolved in aqueous salt solutions of high-valent cations (aluminium(III), iron(III) and chromium(III)) and dissolved almost completely in aqueous salts containing 3.10mmol salts\\/g chitosan. Hydrated salts plasticized chitosan and aqueous aluminium(III) chloride\\/chitosan solution yielded plasticized films with the highest maximal tensile stress and elongation at

Ryuji Hirase; Yukio Higashiyama; Masaru Mori; Yoshiyuki Takahara; Chihiro Yamane

2010-01-01

127

Selective recovery of glycosylated caseinmacropeptide with chitosan.  

PubMed

The use of chitosan, a partially deacetylated chitin, to fractionate aqueous solutions of caseinmacropeptides (CMPs) was studied. The polycationic character of chitosan at acidic pH values allows the formation of complexes with negatively charged CMP molecules, inducing their flocculation. Glycosylated CMP (GMP) has higher affinity for chitosan than nonglycosylated forms (NGMP). The carboxylic groups in the carbohydrate moiety of the GMP increase the negative charge of the molecule and may play a role in the selective precipitation. At pH 5.0, 0.08 mg/mL of chitosan completely removed the GMP whereas 70% of NGMP remained in solution. As the pH increased, the amount of chitosan to ensure complete removal of GMP increased up to 0.19 and 0.34 mg/mL for pH 6.0 and 6.6, respectively. PMID:15713041

Casal, E; Corzo, N; Moreno, F J; Olano, A

2005-02-23

128

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

129

Biodegradable chitosan nanogels crosslinked with genipin.  

PubMed

Chitosan nanoparticles crosslinked with genipin were prepared by reverse microemulsion that allowed to obtain highly monodisperse (3-20 nm by TEM) nanogels. The incorporation of genipin into chitosan was confirmed and quantitatively evaluated by UV-vis and (1)H NMR. Loosely crosslinked chitosan networks showed higher water solubility at neutral pHs than pure chitosan. The hydrodynamic diameter of the genipin-chitosan nanogels ranged from 270 to 390 nm and no remarkable differences were found when the crosslinking degree was varied. The hydrodynamic diameters of the nanoparticles increased slightly at acidic pH and the protonation of ionizable amino groups with the pH was confirmed by the zeta potential measurements. The biocompatible and biodegradable nature, as well as the colloidal and monodisperse particle size of the prepared nanogels, make them attractive candidates for a large variety of biomedical applications. PMID:23544640

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

2013-05-15

130

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

131

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

PubMed Central

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

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

2013-01-01

132

Effect of chitosan and carboxymethyl chitosan on fibrinogen structure and blood coagulation.  

PubMed

Chitosan has numerous biomedical applications such as tissue engineering scaffolds, drug/gene delivery systems, hemostasis materials, antibacterial materials, wound dressing, etc. In any case, chitosan administered in vivo would positively or passively contact or enter blood tissue. In this situation, the interaction of chitosan with blood components is critical to determine the efficacy and safety of the polymer. In this study, the effect of chitosan with different molecular weight and its derivative carboxymethyl chitosan (CMC) on the structure and function of clotting-related proteins was studied. Specifically, the structural and conformational change of fibrinogen, an important clotting protein, was studied by using UV, fluorescence, and circular dichroism spectroscopy, respectively. Further, the impact of chitosan and CMC on the clotting function was evaluated with activated partial thromboplastin time (APTT), prothrombin time (PT), fibrinogen time (FT), and thromboelastography (TEG) assays. These results showed that, chitosan and fibrinogen can form complex mainly by electrostatic attraction. As a result, the structure and conformation of fibrinogen are altered by chitosan and CMC. Additionally, the presence of chitosan and CMC has little impact on the values of APTT, PT and FT, but causes significant abnormality in the clotting process by changing TEG parameters. These results provide important insight into the molecular basis for the biological response to chitosan and other biopolymers. PMID:23848448

Zhang, Wei; Zhong, Dagen; Liu, Quan; Zhang, Yi; Li, Nan; Wang, Qian; Liu, Zonghua; Xue, Wei

2013-01-01

133

Role of sulfhydryl groups in transfection? A case study with chitosan-NAC nanoparticles.  

PubMed

This study investigated the use of chitosan-N-acetylcysteine (NAC) as a non-viral gene carrier. In particular, we aimed to elucidate whether the advantage of thiolation was more pronounced in the stabilization of particles or in the effect of nonspecific sulfhydryl reduction of the target cells. Low-viscosity chitosan was modified by covalent binding of NAC. The resulting conjugate displayed 1.35 mM SH/g polymer. Particles produced via self-assembly of chitosan conjugate and pDNA had a mean particle size of 113.7 nm and a positive zeta-potential. Sulfhydryl group content on the particle surface was investigated by Ellman's test and papain reactivation assay, with the result of about 100 nM SH groups/mL nanoparticle suspension. An oxidation step was performed to stabilize polyplexes via disulfide bonds. The enhanced stability of oxidized particles against both polyanion heparin and alkaline pH was proven by a gel retardation assay. The stabilization was demonstrated to be reversible by treatment with glutathione. Further, the effect of immobilized SH groups and of supplementation with free NAC on transfection efficacy on Caco-2 cells was investigated. The expression of the transgene was raised 2.5-fold and 10-fold with nonoxidized thiomer polyplexes in comparison to polyplexes of unmodified chitosan and oxidized chitosan-NAC, respectively. The impact of sulfhydryl reduction on transfection was assessed via thiol group inactivation with 5,5'-dithiobis-(2-nitrobenzoic acid) (DNTB). This inactivation resulted in a decrease of transfection efficacy. In conclusion, chitosan-NAC conjugate was demonstrated to be beneficial for transfection, either for stabilization via disulfide bonds or for raising the expression of transgene via shifting the redox potential of the target cells. PMID:17552491

Loretz, Brigitta; Thaler, Marlene; Bernkop-Schnürch, Andreas

2007-01-01

134

Microfluidic Fabrication of Cell Adhesive Chitosan Microtubes  

PubMed Central

Chitosan has been used as a scaffolding material in tissue engineering due to its mechanical properties and biocompatibility. With increased appreciation of the effect of micro- and nanoscale environments on cellular behavior, there is increased emphasis on generating microfabricated chitosan structures. Here we employed a microfluidic coaxial flow-focusing system to generate cell adhesive chitosan microtubes of controlled sizes by modifying the flow rates of a chitosan pre-polymer solution and phosphate buffered saline (PBS). The microtubes were extruded from a glass capillary with a 300 ?m inner diameter. After ionic crosslinking with sodium tripolyphosphate (TPP), fabricated microtubes had inner and outer diameter ranges of 70-150 ?m and 120-185 ?m. Computational simulation validated the controlled size of microtubes and cell attachment. To enhance cell adhesiveness on the microtubes, we mixed gelatin with the chitosan pre-polymer solution and adjusted the pH values of the chitosan pre-polymer solution with gelatin and TPP. During the fabrication of microtubes, fibroblasts suspended in core PBS flow adhered to the inner surface of chitosan-gelatin microtubes. To achieve physiological pH values, we adjusted pH values of chiotsan pre-polymer solution and TPP. In particular, we were able to improve cell viability to 92% with pH values of 5.8 and 7.4 for chitosan and TPP solution respectively. Cell culturing for three days showed that the addition of the gelatin enhanced cell spreading and proliferation inside the chitosan-gelatin microtubes. The microfluidic fabrication method for ionically crosslinked chitosan microtubes at physiological pH can be compatible with a variety of cells and used as a versatile platform for microengineered tissue engineering.

Oh, Jonghyun; Kim, Keekyoung; Won, Sung Wook; Cha, Chaenyung; Gaharwar, Akhilesh; Selimovic, Seila; Bae, Hojae; Lee, Kwang Ho; Lee, Dong Hwan; Lee, Sang-Hoon; Khademhosseini, Ali

2013-01-01

135

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

136

Insights into and relative effect of chitosan-H, chitosan-H-propolis, chitosan-H-propolis-nystatin and chitosan-H-nystatin on dentine bond strength  

PubMed Central

Objective: The purpose of the study was to design and evaluate novel functional chitosan hydrogels (chitosan-H-propolis, chitosan-H-propolis-nystatin and chitosan-H-nystatin) by using the chitosan-H polymer as “dual function restorative materials”. Materials and Methods: The nystatin/antioxidant carrier gel was prepared by dispersion of the corresponding component in glycerol and 3% acetic acid with 5% chitosan gelling agent was then added to the dispersion with continuous mixing. The natural bio-adhesive functionalized chitosan hydrogels were combined with built in drug delivery system and bio-actives such as propolis in order to increase the dentin bond strength capacity and maintain therapeutic properties of the alternative drug delivery system. The surface morphology, release behaviors (physiological pH and also in acidic conditions), stability of nystatin:antioxidant:chitosan and the effect of the hydrogels on the shear bond strength of dentin were also evaluated. Statistical Analysis Used: Non-parametric ANOVA test was used to asses significance of higher shear bond values than dentine treated or not treated with phosphoric acid. Results: The release of both nystatin and propolis confer the added benefit of dual action of a functional therapeutic delivery when comparing the newly designed chitosan-based hydrogel restorative materials to commercially available nystatin alone. Neither the release of nystatin nor the antioxidant stability was affected by storage. Chitosan-H, chitosan-propolis, chitosan-nystatin and chitosan-nystatin-propolis treated dentine gives significantly (P < 0.05) higher shear bond values (P < 0.05) than dentine treated or not treated with phosphoric acid. Conclusion: The added benefits of their unique functionality involve increased dentin adhesive bond strengths (after 24 h and after 6 months) and positive influence on the nystatin release. Nystatin was a model therapeutic agent, evaluating the concept of using functional materials as carriers for pro-drugs as well as displaying a certain degree of defence mechanism for free radical damage of the novel functional drug delivery. Overall, there was an insignificant relapse in the shear bond strength after 6 months.

Perchyonok, Victoria Tamara; Zhang, Shengmiao; Grobler, Sias R.; Oberholzer, Theunis G.

2013-01-01

137

Prevention of browning of depolymerized chitosan obtained by gamma irradiation.  

PubMed

In this paper, effect of oxygen and pH on the browning of chitosan exposed to gamma radiation was investigated. It was found that oxygen and pH value could play important roles in the inhibiting browning of irradiated chitosan. When the pH value of chitosan solution was below 3.0, sufficient oxygen could inhibit browning of irradiated chitosan in aqueous solution. As a result of irradiation of chitosan solution (pH<3) with sufficient oxygen, the irradiated chitosan solutions obtained were colorless and pellucid. FT-IR, (13)C NMR, and UV-vis spectra confirmed that the irradiation in the presence of oxygen cannot result in chemical modification of irradiated chitosan. An effective technology was developed for the inhibition of browning of irradiated chitosan during depolymerization of chitosan by gamma irradiation. PMID:24299848

Yue, Wu

2014-01-30

138

Chitosan enhances platelet adhesion and aggregation.  

PubMed

In this study, chitosan (MW=50,000) was tested for its enhancing platelet activity in rabbit platelet suspensions and the possible mechanisms involved were further investigated. Our results showed that after initial (5 min) and long-term (30 min) contact of platelets with chitosan, the platelet adhesion to chitosan-coated microtiter plates was dose-dependently increased compared to that of solvent control. Similarly, chitosan also dose-dependently increased the platelet aggregation and the intracellular free Ca(2+) rise of Fura-2-AM loaded platelets. Additionally, in the presence of FITC-labeled anti-CD41/CD61, chitosan significantly enhanced the expression of platelet glycoprotein IIb/IIIa complex assayed by a flow cytometer. It is concluded that chitosan is an effective inducer for platelet adhesion and aggregation and the mechanisms of action of chitosan may be associated, at least partly, with the increasing [Ca(2+)](i) mobilization and enhancing expression of GPIIb/IIIa complex on platelet membrane surfaces. PMID:12615058

Chou, Tz-Chong; Fu, Earl; Wu, Chang-Jer; Yeh, Jeng-Hsien

2003-03-14

139

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

PubMed Central

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

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

2006-01-01

140

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

141

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

142

Water soluble folate-chitosan nanogels crosslinked by genipin.  

PubMed

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

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

2014-01-30

143

Biologically active amphiphilic derivatives of chitosan  

Microsoft Academic Search

Amphiphilic N-derivatives of chitosan containing C12 alkyl and carboxyl groups were obtained. It was shown that the compounds obtained have fungicidal activity and form intermolecular\\u000a associates in solutions.

E. A. Stepnova; V. E. Tikhonov; V. G. Babak; M. A. Krayukhina; K. K. Babievskii; I. A. Yamskov

2005-01-01

144

Pseudo-dry-spinning of chitosan  

Microsoft Academic Search

A pseudo-dry-spinning process of chitosan without any use of organic solvent or cross-linking agent was studied. A highly deacetylated chitosan (degree of acetylation=2.7%) from squid-pens, with a high weight-average molecular weight (MW=540000g\\/mol) was used. The polymer was dissolved in an acetic acid aqueous solution in order to obtain a polymer concentration of 2.4% w\\/w with a stoichiometric protonation of the

Laure Notin; Christophe Viton; Jean-Michel Lucas; Alain Domard

2006-01-01

145

Radiolysis of chitosan derivatives exhibiting antimutagenic activity  

Microsoft Academic Search

The radiolysis of antimutagens extracted from natural biopolymer chitosan was studied by the EPR method. It was shown that\\u000a addition of gallic acid (2 mol %) to quaternized chitosan results in a 2.5-fold decrease in the radiation-chemical yield of\\u000a radicals and a nearly complete inhibition of the formation of ion radicals. Gallic acid units likely play the role of a

V. A. Alexandrova; S. I. Kuzina; I. A. Shilova; A. I. Mikhailov

2006-01-01

146

Chitosan/Prussian blue-based biosensors  

NASA Astrophysics Data System (ADS)

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

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

2003-06-01

147

Multifunctional properties of cotton fabric treated with chitosan and carboxymethyl chitosan  

Microsoft Academic Search

A water soluble carboxymethyl derivative of chitosan was prepared with a view to develop a multifunctional finish on cotton. Results show that treated cotton has better dyeability with direct and reactive dyes. Treatment with modified chitosan makes it possible to dye cotton in bright shades with cationic dyes having high wash fastness. Treated samples showed good antimicrobial activity against Escherichia

Deepti Gupta; Adane Haile

2007-01-01

148

Dilute solution properties of hexanoyl chitosan in chloroform, dichloromethane, and tetrahydrofuran  

Microsoft Academic Search

Hexanoyl chitosan (H-chitosan), a chitosan derivative, was synthesized using a new method to obtain an organically soluble chitosan derivative. H-chitosan with the degree of substitution of 3.92 was dissolved in selected three organic solvents namely chloroform, dichloromethane, or tetrahydrofuran in order to study the effect of solvent type on H-chitosan solution properties. The solution properties of H-chitosan were determined by

Manisara Peesan; Anuvat Sirivat; Pitt Supaphol; Ratana Rujiravanit

2006-01-01

149

Polyethylene Glycol on Stability of Chitosan Microparticulate Carrier for Protein  

Microsoft Academic Search

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

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

2010-01-01

150

Preparations, characterizations and applications of chitosan-based nanoparticles  

Microsoft Academic Search

Chitosan is a natural polysaccharide prepared by the N-deacetylation of chitin. In this paper we have reviewed the methods\\u000a of preparation of chitosan-based nanoparticles and their pharmaceutical applications. There are five methods of their preparations:\\u000a emulsion cross-linking, emulsion-droplet coalescence, ionic gelation, reverse micellar method and chemically modified chitosan\\u000a method. Chitosan nanoparticles are used as carriers for low molecular weight drug,

Chenguang Liu; Yulong Tan; Chengsheng Liu; Xiguang Chen; Lejun Yu

2007-01-01

151

Radiation-induced degradation of carboxymethylated chitosan in aqueous solution  

Microsoft Academic Search

Aqueous solutions of carboxymethylated chitosan (CM-chitosan) were radiated with ?-ray in various conditions. The degradations of CM-chitosan were faster in the presence of nitrous oxide or hydrogen peroxide, but it was inhibited obviously after adding isopropanol because of the changes of the concentration of hydroxyl radicals in above different conditions. The radiation chemical yields of CM-chitosan degradation were found to

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

2007-01-01

152

Preparations, characterizations and applications of chitosan-based nanoparticles  

NASA Astrophysics Data System (ADS)

Chitosan is a natural polysaccharide prepared by the N-deacetylation of chitin. In this paper we have reviewed the methods of preparation of chitosan-based nanoparticles and their pharmaceutical applications. There are five methods of their preparations: emulsion cross-linking, emulsion-droplet coalescence, ionic gelation, reverse micellar method and chemically modified chitosan method. Chitosan nanoparticles are used as carriers for low molecular weight drug, vaccines and DNA. Releasing characteristics, biodistribution and applications are also summarized.

Liu, Chenguang; Tan, Yulong; Liu, Chengsheng; Chen, Xiguang; Yu, Lejun

2007-07-01

153

Biomedical applications of superparamagnetic iron oxide nanoparticles encapsulated within chitosan  

Microsoft Academic Search

Microspheres composed of superparamagnetic iron oxide (SPIO; Fe3O4; magnetite) nanoparticles and chitosan were developed as a novel MRI-detectable embolic material. Spherical SPIO nanoparticles were synthesized and embedded in polyglucosamine (chitosan) by sonochemical method. The ferrofluid, solution of SPIO-embedded chitosan, was sprayed on the surface of an alkali solution with a nozzle to produce SPIO-chitosan microspheres, from which 100–150?m microspheres were

Eun Hee Kim; Yangkyu Ahn; Hyo Sook Lee

2007-01-01

154

Fabrication of chitosan-poly(ethylene glycol) hybrid hydrogel microparticles via replica molding and its application toward facile conjugation of biomolecules.  

PubMed

We demonstrate a facile scheme to fabricate nonspherical chitosan-poly(ethylene glycol) (PEG) microparticle platforms for conjugation of biomolecules with high surface density. Specifically, we show that PEG microparticles containing short chitosan oligomers are readily fabricated via replica molding (RM). Fluorescence and FTIR microscopy results illustrate that these chitosan moieties are incorporated with PEG networks in a stable manner while retaining chemical reactivity toward amine-reactive chemistries. The chitosan-PEG particles are then conjugated with single-stranded (ss) DNAs via Cu-free click chemistry. Fluorescence and confocal microscopy results show facile conjugation of biomolecules with the chitosan-PEG particles under mild conditions with high selectivity. These ssDNA-conjugated chitosan-PEG particles are then enlisted to assemble tobacco mosaic virus (TMV) via nucleic acid hybridization as an example of orientationally controlled conjugation of supramolecular targets. Results clearly show controllable TMV assembly with high surface density, indicating high surface DNA density on the particles. Combined, these results demonstrate a facile fabrication-conjugation scheme for robust biomolecular conjugation or assembly platforms. We expect that our approach can be enlisted in a wide array of biomolecular targets and applications. PMID:23163737

Jung, Sukwon; Yi, Hyunmin

2012-12-11

155

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

PubMed Central

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

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

2013-01-01

156

Preparation of alginate coated chitosan microparticles for vaccine delivery  

Microsoft Academic Search

BACKGROUND: Absorption of antigens onto chitosan microparticles via electrostatic interaction is a common and relatively mild process suitable for mucosal vaccine. In order to increase the stability of antigens and prevent an immediate desorption of antigens from chitosan carriers in gastrointestinal tract, coating onto BSA loaded chitosan microparticles with sodium alginate was performed by layer-by-layer technology to meet the requirement

XingYi Li; XiangYe Kong; Shuai Shi; XiuLing Zheng; Gang Guo; YuQuan Wei; ZhiYong Qian

2008-01-01

157

Preparation and in vitro evaluation of thiolated chitosan microparticles.  

PubMed

The objective of this study was to prepare a microparticulate drug delivery system being based on a new thiomer, namely a chitosan 2-iminothiolane conjugate (chitosan-TBA conjugate). Due to thiol groups being immobilized on chitosan, chitosan-TBA conjugate exhibits improved mucoadhesive and permeation enhancing properties. Because of these features microparticulate drug delivery systems based on chitosan-TBA conjugate might be a promising tool for the non-invasive administration of hydrophilic macromolecular drugs. Chitosan-TBA conjugate microspheres were prepared by the emulsification/solvent evaporation method. Fluorescein-isothiocyanate labelled dextran (FITC-dextran) was chosen as a model hydrophilic drug. Microspheres have been characterized by morphological analysis, thiol group content, swelling behaviour, polymer degradation drug load determination, dissolution test and mucoadhesion studies. Results reported in this work demonstrated the possibility to obtain stable microspheres without cross-linking agents. Thiolated chitosan microspheres seem to be more stable in aqueous media with respect to unmodified chitosan. The degradability by lysozyme appears quite similar for both polymers, showing that chemical modification does not influence the biodegradable properties of chitosan. Microspheres were able to control the drug release for at least 1 h, exhibiting comparatively strong mucoadhesive properties. The chitosan-TBA conjugate microparticles remain on the mucosa in a 2.5-fold higher concentration with respect to unmodified chitosan microparticles. These data suggest that chitosan-TBA conjugate microspheres have the potential to be used as a mucoadhesive drug delivery system. PMID:16361190

Maculotti, K; Genta, I; Perugini, P; Imam, M; Bernkop-Schnürch, A; Pavanetto, F

2005-08-01

158

Biomaterials based on chitin and chitosan in wound dressing applications  

Microsoft Academic Search

Wound dressing is one of the most promising medical applications for chitin and chitosan. The adhesive nature of chitin and chitosan, together with their antifungal and bactericidal character, and their permeability to oxygen, is a very important property associated with the treatment of wounds and burns. Different derivatives of chitin and chitosan have been prepared for this purpose in the

R. Jayakumar; M. Prabaharan; P. T. Sudheesh Kumar; S. V. Nair; H. Tamura

2011-01-01

159

Preparation of carboxymethyl chitosan in aqueous solution under microwave irradiation  

Microsoft Academic Search

Carboxymethyl chitosan was prepared by reacting chitosan with chloroacetic acid in water under microwave irradiation. The effect of the reaction conditions was investigated and optimal conditions were identified. The influence of mass ratio of chloroacetic acid to chitosan, microwave power and pH on the degree of substitution or intrinsic viscosity were further studied. The degree of substitution of the carboxymethyl

Hua-Cai Ge; Deng-Ke Luo

2005-01-01

160

Radiation sterilization of chitosan sealant for vascular prostheses  

Microsoft Academic Search

Chitosan was used as a sealant of knitted polyester vascular grafts. Three sterilization methods for chitosan-coated prostheses were tested: sterilization with ethylene oxide, formaldehyde and irradiation with gamma rays. Radiation sterilization was found to be the most promising of tested methods. The radiation-induced changes in chitosan irradiated in solid state were investigated. Main chain scission was found as the predominant

J. Rosiak; P. Ula?ski; M. Kucharska; J. Dutkiewicz; L. Judkiewicz

1992-01-01

161

Chitosan and Its Use as a Pharmaceutical Excipient  

Microsoft Academic Search

Chitosan has been investigated as an excipient in the pharmaceutical industry, to be used in direct tablet compression, as a tablet disintegrant, for the production of controlled release solid dosage forms or for the improvement of drug dissolution. Chitosan has, compared to traditional excipients, been shown to have superior characteristics and especially flexibility in its use. Furthermore, chitosan has been

Lisbeth Ilium

1998-01-01

162

Fungal mycelium—the source of chitosan for chromatography  

Microsoft Academic Search

Mycelium of the mold Aspergillus niger was used as a raw material for the preparation of microbial chitosan. Aspergillus niger, the mold used for the production of citric acid, contains approx. 15% of chitin, which can be separated, transformed into chitosan, and used as a sorbent for chromatography. The main advantage of this material in comparison with krill chitosan is

Ji?i Ku?era

2004-01-01

163

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

164

Biologically Active Polymers: Modification and Antimicrobial Activity of Chitosan Derivatives  

Microsoft Academic Search

The principal derivative of chitin is chitosan, which is obtained by deacetylation of chitin. Chemical modification of synthetic and natural polymers is a convenient way to obtain materials with unique chemical and physical properties. Chitosan has an amino group at C-2 which is important because amino groups are nucleophilic and readily react with electrophilic reagents. Chitosan modified under mild conditions

El-Refaie Kenawy; F. Imam Abdel-Hay; Ahmed Abou El-Magd; Yehia Mahmoud

2005-01-01

165

Chitosan as a functional interface between biology and microsystems  

Microsoft Academic Search

We report the use of the amino polysaccharide chitosan for the immobilization and patterning of biomolecules on microfabricated surfaces. Chitosan is a biocompatible and biodegradable substance derived from chitin, which is the structural material in the exoskeleton of crustaceans. Chitosan has two key properties of interest to biologists and engineers alike. First, it has an abundance of primary amine groups

S. T. Koev; M. A. Powers; J. J. Park; H. Yi; L. Wu; W. E. Bentley; G. F. Payne; G. W. Rubloff; R. Ghodssi

2006-01-01

166

Forensic Fingerprint Enhancement using Bioadhesive Chitosan and Gold Nanoparticles  

Microsoft Academic Search

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

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

2007-01-01

167

Lecithin/chitosan nanoparticles of clobetasol-17-propionate capable of accumulation in pig skin.  

PubMed

In this study, clobetasol-17-propionate (CP) loaded lecithin/chitosan nanoparticles were studied with special attention to the transport of the active agent across the skin in vitro. Nanoparticles were characterized by measuring particle size, zeta potential, polydispersity index and encapsulation efficiency. The morphology of nanoparticles was evaluated by transmission electron microscopy. Encapsulation experiments with CP showed high encapsulation efficiency (92.2%). To assess the advantages of this carrier-based formulation in topical administration, the accumulation in and permeation across pig ear skin were compared with chitosan gel and commercially available cream of CP. The results obtained indicate that the incorporation of drug into nanoparticles induced an accumulation of CP especially in the epidermis without any significant permeation across the skin. Dilution of CP loaded nanoparticles with chitosan gel (1:9) produced the same amount of CP in the skin compared with commercial cream, although the former contained ten times less CP. This is a remarkable point for the reduction of the side effects of CP. These results demonstrated the suitability of lecithin/chitosan nanoparticles to induce epidermal targeting and to improve the risk-benefit ratio for topically applied CP. PMID:19932722

Senyi?it, Taner; Sonvico, Fabio; Barbieri, Stefano; Ozer, Ozgen; Santi, Patrizia; Colombo, Paolo

2010-03-19

168

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

PubMed

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

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

2014-07-17

169

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

170

A comparison of the structure, thermal properties, and biodegradability of polycaprolactone\\/chitosan and acrylic acid grafted polycaprolactone\\/chitosan  

Microsoft Academic Search

The effects of replacing PCL with acrylic acid grafted PCL (PCL-g-AA) on the structure and properties of a PCL\\/chitosan composite were investigated. The properties of both PCL-g-AA\\/chitosan and PCL\\/chitosan were examined and compared using FTIR, 1H and 13C nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), and a biodegradation test. With PCL-g-AA in the composite, compatibility with chitosan and, consequently,

Chin-San Wu

2005-01-01

171

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

172

Formation and dissolution of chitosan/pyrophosphate nanoparticles: is the ionic crosslinking of chitosan reversible?  

PubMed

Ionically crosslinked chitosan particles with submicron dimensions attract widespread interest as materials for controlled release. To this end, we have examined the formation and dissolution of nanoparticles prepared by crosslinking chitosan with pyrophosphate (PPi). The formation of these particles required a critical PPi concentration (which increased with the chitosan concentration), and their z-average hydrodynamic diameters could be predictably tuned from roughly 60 to 220 nm by varying the concentration of the parent chitosan solutions. Unlike the nanoparticles crosslinked with the commonly used tripolyphosphate (TPP), which coagulated and precipitated when TPP was in excess, the chitosan/PPi nanoparticles remained colloidally stable even at high PPi concentrations. Moreover, the analysis of their dissolution revealed hysteresis in the particle formation/dissolution cycle, where portions of the crosslinked chitosan/PPi complexes remained stably intact at PPi concentrations below those required for their formation. This irreversible behavior was surmised to reflect the cooperativity of chitosan/PPi binding and was qualitatively modeled using the Bragg-Williams theory. PMID:24333908

Cai, Yuhang; Lapitsky, Yakov

2014-03-01

173

Chitosan-silica hybrid porous membranes.  

PubMed

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

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

2014-09-01

174

Pseudo-dry-spinning of chitosan.  

PubMed

A pseudo-dry-spinning process of chitosan without any use of organic solvent or cross-linking agent was studied. A highly deacetylated chitosan (degree of acetylation=2.7%) from squid-pens, with a high weight-average molecular weight (M(W)=540,000 g/mol) was used. The polymer was dissolved in an acetic acid aqueous solution in order to obtain a polymer concentration of 2.4% w/w with a stoichiometric protonation of the -NH(2) sites. The coagulation method consisted of subjecting the extruded monofilament to gaseous ammonia. The alkaline coagulation bath classically used in a wet-spinning process was therefore not useful. A second innovation dealt with the absence of any aqueous washing bath after coagulation. The gaseous coagulation was then directly followed by a drying step under hot air. When the chitosan monofilament coagulated in the presence of ammonia gas, ammonium acetate produced with the fiber could be hydrolyzed into acetic acid and ammonia, easily eliminated in their gaseous form during drying. The pseudo-dry-spinning process did not give rise to any strong degradation of polymer chains. After 2 months at ambient atmosphere, chitosan fibers could then be stored without any significant decrease in the M(W), which remained at a rather high value of 350,000 g/mol. The obtained chitosan fibers showed a smooth, regular and uniformly striated surface. PMID:16701889

Notin, Laure; Viton, Christophe; Lucas, Jean-Michel; Domard, Alain

2006-05-01

175

Chitosan inhibits premature browning in ground beef.  

PubMed

Our objective was to evaluate the effect of chitosan on premature browning in refrigerated ground beef patties stored in different packaging systems. Ground beef patties (15% fat) with chitosan (1% w/w) or without chitosan (control) were individually packaged either in vacuum (VP), aerobic packaging (AP), carbon monoxide modified atmosphere packaging (LO-OX; 0.4% CO+19.6% CO(2)+80% N(2)), or high-oxygen modified atmosphere packaging (HI-OX; 80% O(2)+20% CO(2)), and stored for 0, 1, or 3 days at 1°C. At the conclusion of storage, raw surface redness was evaluated, patties were cooked to internal end-point temperatures of either 66°C or 71°C, and internal cooked color was measured. The incorporation of chitosan increased (P<0.05) the interior redness of patties stored in AP, VP, and LO-OX, but not in HI-OX. The results of the present study suggest that the incorporation of 1% chitosan minimizes premature browning in ground beef patties stored under AP, VP, and LO-OX. PMID:21396786

Suman, S P; Mancini, R A; Joseph, P; Ramanathan, R; Konda, M K R; Dady, G; Yin, S

2011-07-01

176

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

177

Chitosan fibers modified with HAp/?-TCP nanoparticles.  

PubMed

This paper describes a method for preparing chitosan fibers modified with hydroxyapatite (HAp), tricalcium phosphate (?-TCP), and HAp/?-TCP nanoparticles. Fiber-grade chitosan derived from the northern shrimp (Pandalus borealis) and nanoparticles of tricalcium phosphate (?-TCP) and hydroxyapatite (HAp) suspended in a diluted chitosan solution were used in the investigation. Diluted chitosan solution containing nanoparticles of Hap/?-TCP was introduced to a 5.16 wt% solution of chitosan in 3.0 wt% acetic acid. The properties of the spinning solutions were examined. Chitosan fibers modified with nanoparticles of HAp/?-TCP were characterized by a level of tenacity and calcium content one hundred times higher than that of regular chitosan fibers. PMID:22174598

Wawro, Dariusz; Pighinelli, Luciano

2011-01-01

178

Chitosan Fibers Modified with HAp/?-TCP Nanoparticles  

PubMed Central

This paper describes a method for preparing chitosan fibers modified with hydroxyapatite (HAp), tricalcium phosphate (?-TCP), and HAp/?-TCP nanoparticles. Fiber-grade chitosan derived from the northern shrimp (Pandalus borealis) and nanoparticles of tricalcium phosphate (?-TCP) and hydroxyapatite (HAp) suspended in a diluted chitosan solution were used in the investigation. Diluted chitosan solution containing nanoparticles of Hap/?-TCP was introduced to a 5.16 wt% solution of chitosan in 3.0 wt% acetic acid. The properties of the spinning solutions were examined. Chitosan fibers modified with nanoparticles of HAp/?-TCP were characterized by a level of tenacity and calcium content one hundred times higher than that of regular chitosan fibers.

Wawro, Dariusz; Pighinelli, Luciano

2011-01-01

179

Effect of chitosan coatings on postharvest green asparagus quality.  

PubMed

Fresh postharvest green asparagus rapidly deteriorate due to its high respiration rate. The main benefits of edible active coatings are their edible characteristics, biodegradability and increase in food safety. In this study, the quality of the edible coatings based on 0.50%, 0.25% high-molecular weight chitosan (H-chitosan), and 0.50%, 0.25% low-molecular weight chitosan (L-chitosan) on postharvest green asparagus was investigated. On the basis of the results obtained, 0.25% H-chitosan and 0.50% L-chitosan treatments ensured lower color variation, less weight loss and less ascorbic acid, decrease presenting better quality of asparagus than other concentrations of chitosan treatments and the control during the cold storage, and prolonging a shelf life of postharvest green asparagus. PMID:23399254

Qiu, Miao; Jiang, Hengjun; Ren, Gerui; Huang, Jianying; Wang, Xiangyang

2013-02-15

180

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

181

Solid polymer electrolyte from phosphorylated chitosan  

NASA Astrophysics Data System (ADS)

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

Fauzi, Iqbal; Arcana, I. Made

2014-03-01

182

78 FR 70308 - Prospective Grant of Exclusive License: Development of Chitosan/IL-12 Conjugate as...  

Federal Register 2010, 2011, 2012, 2013

...of Exclusive License: Development of Chitosan/ IL-12 Conjugate as Immunotherapeutic...entitled ``Compositions And Methods For Chitosan Enhanced Immune Response'' [HHS Ref...entitled ``Compositions And Methods For Chitosan Enhanced Immune Response'' [HHS...

2013-11-25

183

NMR investigation of chitosan derivatives formed by the reaction of chitosan with levulinic acid  

Microsoft Academic Search

Chitosan derivatives are obtained by reaction of chitosan with a low degree of acetylation and levulinic acid under different experimental conditions. The chemical structure of the different derivatives obtained is determined using 1H and 13C NMR spectroscopies. The intrinsic viscosity is used to follow the molecular weight evolution. Finally, conditions are described in which water-soluble N-carboxybutylchitosan is obtained. In particular,

M Rinaudo; J Desbrières; P Le Dung; P Thuy Binh; N. T Dong

2001-01-01

184

Development of some bio-composite materials hydroxyapatite\\/chitosan and TiO2\\/chitosan  

Microsoft Academic Search

New-type materials, which consist of organic and inorganic compounds, have been prepared. The materials have various functions and specific nature because of their improved mechanical, thermal, optical, or chemical properties relative to the organic or inorganic materials alone. The aim of this study is to prepare and characterise micro composite films hydroxyapatite\\/chitosane and TiO2\\/chitosane of which the use could be

S. Essakali; A. Kheribech; M. Bakasse; Z. Hatim

2008-01-01

185

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

186

Simultaneous depolymerization and decolorization of chitosan by ozone treatment.  

PubMed

Currently, depolymerization and decolorization of chitosan are achieved by chemical or enzymatic methods, which are time consuming and expensive. Ozone has been shown to be able to degrade macromolecules and remove pigments due to its high oxidation potential. In this study, the effects of ozone treatment on depolymerization and decolorization of chitosan were investigated. Crawfish chitosan was ozonated in water and acetic acid solution for 0, 5, 10, 15, and 20 min at room temperature with 12 wt% gas. In this study, the effects of ozone treatment on depolymerization and decolorization of chitosan were investigated by measuring the molecular weight, viscosity, and color of chitosan. The color of ozone-treated chitosan was analyzed using a Minolta spectrophotometer. The degree of deacetylation was determined by a colloid titration method. Molecular weight of ozone-treated chitosan in acetic acid solution decreased appreciably as the ozone treatment duration increased. Ozonation for 20 min reduced the molecular weight of the chitosan by 92% (104 kDa) compared to the untreated chitosan (1333 kDa) with a decrease in viscosity of the chitosan solution. Ozonation for 5 min markedly increased the whiteness of chitosan with a molecular weight of 432 kDa; however, further ozonation resulted in development of yellowness. In the case of the ozonation in water, there were no significant differences in the molecular weight and color between ozone-treated chitosans. This study showed that ozone can be used to modify molecular weight and remove pigments of chitosan without chemical use in a shorter time and with less cost. PMID:18034714

Seo, S; King, J M; Prinyawiwatkul, W

2007-11-01

187

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

188

Chitosan nanoparticles loaded with dorzolamide and pramipexole  

Microsoft Academic Search

Chitosan (CS) nanoparticles of dorzolamide hydrochloride (Dorzo) and pramipexole hydrochloride (Prami) were prepared by the ionic gelation method and their in vitro properties were studied. The long-term objective is the development of efficient ocular formulations for Dorzo and efficient oral formulations for Prami. The particle size of nanoparticles was affected by the CS\\/drug ratio whereas it was not affected by

Sofia Papadimitriou; Dimitrios Bikiaris; Konstantinos Avgoustakis; Evangelos Karavas; Manolis Georgarakis

2008-01-01

189

Photochemical tissue bonding with chitosan adhesive films  

PubMed Central

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

2010-01-01

190

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

191

Method for Insolubilizing Enzymes on Chitosan.  

National Technical Information Service (NTIS)

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

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

1976-01-01

192

Permeability Evaluation Through Chitosan Membranes Using Taguchi Design  

PubMed Central

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

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

2010-01-01

193

[Adsorption behaviors of chitosan and the analysis of FTIR spectra].  

PubMed

This paper studied the adsorption behavior of lab-made chitosan for acid dyeing waste water and basic dyeing waste waters, based on the effects of adsorbing time, deacetylation degree of chitosan, and pH of waste water. The results showed that the adsorption of basic fuchsin and saffron by the chitosan almost reached equilibrium state in 20 min. The adsorption capacities of the chitosan for dyes was comparable with activated carbon. Moreover, its dosages were only 2/3 of the latter. The adsorption process for Acid Red presented a dynamics character of first order reaction. FTIR spectroscopy was used to analyze the adsorption mechanisms of chitosan for different kinds of dyes. It was found that a great deal of hydroxide radicals in the chitosan molecule participated in the adsorption of basic fuchsin and saffron. PMID:16128066

Huang, Zhong-Hua; Sun, Xiu-Yun; Li, Yan; Ge, Wei; Wang, Jun-De

2005-05-01

194

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

195

DNA biosensor based on chitosan film doped with carbon nanotubes  

Microsoft Academic Search

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

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

2005-01-01

196

Manufacturing monodisperse chitosan microparticles containing ampicillin using a microchannel chip  

Microsoft Academic Search

The purpose of this study was using a developed microfluidic chip to prepare size-controlled monodisperse chitosan microparticles\\u000a encapsulating ampicillin. Our strategy is that a chitosan aqueous solution (the disperse phase) is fed into the microfluidic\\u000a chip equipped with a cross-junction microchannel, and is sheared by the viscous oil flows (the continuous phase) to form monodisperse\\u000a semi-product, chitosan emulsions. These fine

Chih-Hui Yang; Keng-Shiang Huang; Jia-Yaw Chang

2007-01-01

197

Multiresponse optimization of the properties of albendazole–chitosan microparticles  

Microsoft Academic Search

The loading of albendazole into biodegradable polymeric microparticles provides an attractive alternative to improve the drug dissolution rate. Experimental design and optimization techniques were implemented for the development of albendazole–chitosan microparticles using the ionic interaction method. The effect of seven different factors (chitosan concentration, pH of chitosan solution, stirring rate, stirring time, temperature, ionic agent and pH of ionic solutions)

Dario Leonardi; Maria C. Lamas; Alejandro C. Olivieri

2008-01-01

198

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).

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

2011-01-01

199

Polymer batteries with chitosan electrolyte mixed with sodium perchlorate  

Microsoft Academic Search

1 g chitosan was dissolved in 100 ml of 1% acetic acid solution. The solution was then mixed with sodium perchlorate. This chitosan-acetic acid-sodium perchlorate solution was then made into a thin film by the solution cast technique. Eight films were prepared each containing 1 g of chitosan in 100 ml of 1% acetic acid solution and 0.5 g, 1.0

R. H. Y. Subban; A. K. Arof; S. Radhakrishna

1996-01-01

200

N-PEG’ylation of chitosan via “click chemistry” reactions  

Microsoft Academic Search

N-azidated chitosan was prepared by four different methods: using azidated epichlorohydrin, sodium azide plius sodium nitrite, trifluoromethane sulfonyl azide or imidazole-1-sulfonyl azide hydrochloride. Using the two last reagents, the degree of azidation (DA) of chitosan was up to 40% and 65%, respectively. N-azidated chitosans with DA at about 60% were insoluble in aqueous and common organic solvents but dissolved in

Ruta Kulbokaite; Gediminas Ciuta; Milos Netopilik; Ricardas Makuska

2009-01-01

201

Chitosan nanoparticles for oral drug and gene delivery  

PubMed Central

Chitosan is a widely available, mucoadhesive polymer that is able to increase cellular permeability and improve the bioavailability of orally administered protein drugs. It can also be readily formed into nanoparticles able to entrap drugs or condense plasmid DNA. Studies on the formulation and oral delivery of such chitosan nanoparticles have demonstrated their efficacy in enhancing drug uptake and promoting gene expression. This review summarizes some of these findings and highlights the potential of chitosan as a component of oral delivery systems.

Bowman, Katherine; Leong, Kam W

2006-01-01

202

Remediation of coal mining wastewaters using chitosan microspheres  

Microsoft Academic Search

This study aimed to evaluate the potential use of chitosan and chitosan\\/poly(vinylalcohol) microspheres incorporating with tetrasulphonated copper (II) phthalocyanine (CTS\\/PVA\\/TCP) in the remediation of coal mining wastewaters. The process was monitored by toxicity tests both before and after adsorption treatments with chitosan and microspheres. Physicochemical parameters, including pH and trace?metal concentration, as well as bioindicators of water pollution were used

R. Geremias; R. C. Pedrosa; J. C. Benassi; V. T. Fávere; J. Stolberg; C. T. B. Menezes; M. C. M. Laranjeira

2003-01-01

203

Physicochemical and functional characteristics of radiation-processed shrimp chitosan  

Microsoft Academic Search

The effects of gamma irradiation on chitosan samples were determined in terms of physicochemical and functional properties. Shrimp chitosan was extracted from shell using a chemical process involving demineralization, deproteinization, decolorization and deacetylation. Commercial snow chitosan was also used. Samples (in a solid state) were given irradiation dose of 25kGy at a dose rate of 1.1013kGy\\/h in air and 0kGy

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

2011-01-01

204

Systematic fabrication of chitosan nanoparticle by gamma irradiation  

Microsoft Academic Search

The present investigation is mainly focused on the systematic preparation of chitosan nanoparticle in the potential range 1–100nm using ?-ray irradiation. The effect of irradiation conditions in terms of physical form of chitosan, i.e. flake, colloidal and acidic solution, and ?-ray dose was studied. The molecular weights of chitosan were 10, 25, and >1000 times reduced when irradiated with the

Wanvimol Pasanphan; Pakjira Rimdusit; Surakarn Choofong; Thananchai Piroonpan; Sunchai Nilsuwankosit

2010-01-01

205

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

PubMed Central

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

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

2008-01-01

206

A new method of controlled grafting modification of chitosan via nitroxide-mediated polymerization using chitosan-TEMPO macroinitiator.  

PubMed

The controlled graft modification of chitosan has first been achieved by nitroxide-mediated polymerization using chitosan-TEMPO macroinitiator. Chitosan-TEMPO macroinitiator was obtained from the (60)Co gamma-ray irradiation of N-phthaloylchitosan and 4-hydroxy-TEMPO in DMF under argon atmosphere. The graft copolymers were characterized by (1)H nuclear magnetic resonance ((1)H NMR), Fourier transform infrared spectrometer (FT-IR), X-ray powder diffractometer (XRD) and high performance particle sizer (HPPS). The results indicate that the graft copolymers were successfully synthesized and that the graft polymerization was well controlled by the nitroxide-mediated process. The size distribution of chitosan-g-polystyrene in benzene is very narrow, which may be associated with the "well-defined" polystyrene (PSt) onto chitosan from nitroxide-mediated polymerization. This work provides a new method to prepare chitosan grafting copolymers with controlled molecular weights and "well-defined" structures. PMID:18279949

Hua, Daoben; Deng, Weicai; Tang, Jing; Cheng, Jianxin; Zhu, Xiulin

2008-07-01

207

Dual effects of chitosan decoration on the liposomal membrane physicochemical properties as affected by chitosan concentration and molecular conformation.  

PubMed

This study was devoted to a further understanding of the dependence of liposomal membrane properties on chitosan conformation and proved the dual effects of chitosan. The concentration dependence of chitosan conformation in aqueous solution was illustrated by surface tension and fluorescence probe techniques. Fluorescence and Raman spectra were subsequently employed to investigate the dynamic and structural changes of the liposomal membrane resulting from chitosan decoration. Results showed that the unfolded and crimped chains of chitosan flatly adsorbed onto the membrane surface via electrostatic attraction and favored liposome stability. Furthermore, the adsorption of crimped chains seemed stronger due to the embedding of their hydrophobic moieties. However, the presence of chitosan coils induced the increase in membrane fluidity, the intrachain disorder in lipid molecules, and the gauche conformation change of choline group. Dynamic light scattering and lipid oxidation measurements demonstrated that this perturbation was correlated with the permeation of coils into the lipid bilayer. PMID:23772808

Tan, Chen; Xue, Jin; Eric, Karangwa; Feng, Biao; Zhang, Xiaoming; Xia, Shuqin

2013-07-17

208

Biomaterials based on chitin and chitosan in wound dressing applications.  

PubMed

Wound dressing is one of the most promising medical applications for chitin and chitosan. The adhesive nature of chitin and chitosan, together with their antifungal and bactericidal character, and their permeability to oxygen, is a very important property associated with the treatment of wounds and burns. Different derivatives of chitin and chitosan have been prepared for this purpose in the form of hydrogels, fibers, membranes, scaffolds and sponges. The purpose of this review is to take a closer look on the wound dressing applications of biomaterials based on chitin, chitosan and their derivatives in various forms in detail. PMID:21262336

Jayakumar, R; Prabaharan, M; Sudheesh Kumar, P T; Nair, S V; Tamura, H

2011-01-01

209

Inhibition of acetylcholinesterase by gallic acid- grafted-chitosans  

Microsoft Academic Search

This paper discusses acetylcholinesterase inhibitory properties of gallic acid-grafted-chitosans (GA-g-chitosans) with different grafting ratios. The GA-g-chitosans exhibited potent acetylcholinesterase inhibitory effects in a dose-dependent manner, and their IC50 values ranged from 138.5±0.25 to 397.6±5.2?g\\/mL. The acetylcholinesterase inhibition kinetics of the GA-g-chitosan (I) by Lineweaver–Burk plots showed a decrease in Vmax, whereas Km was not altered, thus suggesting a non-competitive mode

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

2011-01-01

210

Biochemical properties of Hemigraphis alternata incorporated chitosan hydrogel scaffold.  

PubMed

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

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

2013-02-15

211

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

PubMed

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

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

2011-01-10

212

Wet spinning of fibers made of chitosan and chitin nanofibrils.  

PubMed

Biocompatible and bioresorbable composite fibers consisting of chitosan filled with anisotropic chitin nanofibrils with the length of 600-800 nm and cross section of about 11-12 nm as revealed by SEM and XRD were prepared by coagulation. Both chitin and chitosan components of the composite fibers displayed preferred orientations. Orientation of chitosan molecules induced by chitin nanocrystallites was confirmed by molecular modeling. The incorporation of 0.1-0.3 wt.% of chitin nanofibrils into chitosan matrix led to an increase in strength and Young modulus of the composite fibers. PMID:24751262

Yudin, Vladimir E; Dobrovolskaya, Irina P; Neelov, Igor M; Dresvyanina, Elena N; Popryadukhin, Pavel V; Ivan'kova, Elena M; Elokhovskii, Vladimir Yu; Kasatkin, Igor A; Okrugin, Boris M; Morganti, Pierfrancesco

2014-08-01

213

Applied usage of yeast spores as chitosan beads.  

PubMed

In this study, we present a nonhazardous biological method of producing chitosan beads using the budding yeast Saccharomyces cerevisiae. Yeast cells cultured under conditions of nutritional starvation cease vegetative growth and instead form spores. The spore wall has a multilaminar structure with the chitosan layer as the second outermost layer. Thus, removal of the outermost dityrosine layer by disruption of the DIT1 gene, which is required for dityrosine synthesis, leads to exposure of the chitosan layer at the spore surface. In this way, spores can be made to resemble chitosan beads. Chitosan has adsorptive features and can be used to remove heavy metals and negatively charged molecules from solution. Consistent with this practical application, we find that spores are capable of adsorbing heavy metals such as Cu(2+), Cr(3+), and Cd(2+), and removal of the dityrosine layer further improves the adsorption. Removal of the chitosan layer decreases the adsorption, indicating that chitosan works as an adsorbent in the spores. Besides heavy metals, spores can also adsorb a negatively charged cholesterol derivative, taurocholic acid. Furthermore, chitosan is amenable to chemical modifications, and, consistent with this property, dit1? spores can serve as a carrier for immobilization of enzymes. Given that yeast spores are a natural product, our results demonstrate that they, and especially dit1? mutants, can be used as chitosan beads and used for multiple purposes. PMID:24907339

Zhang, Haini; Tachikawa, Hiroyuki; Gao, Xiao-Dong; Nakanishi, Hideki

2014-08-15

214

Adsorption properties of carboxymethyl-chitosan and cross-linked carboxymethyl-chitosan resin with Cu(II) as template  

Microsoft Academic Search

Chitosan is an efficient metal chelater, but its practical use is limited due to the stability in acid solutions, adsorption capacities and selectivity. In the study, we attempt to find a more effective new adsorbent based on cross-linked chitosan derivative with Cu(II) as template, so a series of N,O-carboxymethyl-chitosan (CMC) with different degree of substitution (DS) were synthesized, and the

Shengling Sun; Aiqin Wang

2006-01-01

215

Application of Ferriferous Oxide Modified by Chitosan in Gene Delivery  

PubMed Central

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

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

2012-01-01

216

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

217

3D Porous Chitosan Scaffolds Suit Survival and Neural Differentiation of Dental Pulp Stem Cells.  

PubMed

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

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

2014-08-01

218

In vitro screening for anti-microbial activity of chitosans and chitooligosaccharides, aiming at potential uses in functional textiles.  

PubMed

Antimicrobial finishing of textiles has been found to be an economical way to prevent (or treat) skin disorders. Hence, this research effort was aimed at elucidating the relationship between molecular weight (MW) of chitosan and its antimicrobial activity upon six dermal reference microorganisms, as well as the influence of the interactions with cotton fabrics on said activity. Using 3 chitosans with different MW, as well as two chitooligosaccharide (COS) mixtures, a relevant antimicrobial effect was observed by 24 h for the six microorganisms tested; it was apparent that the antimicrobial effect is strongly dependent on the type of target microorganism and on the MW of chitosan being higher for lower MW in the case of E. coli, K. pneumoniae and P. aeruginosa, and the reverse in the case of both Gram-positive bacteria. Furthermore, a strong anti-fungal effect was detectable upon C. albicans, resembling the action over Gram-positive bacteria. Interactions with cotton fabric resulted in a loss of COS activity when compared with cultured media, relative to the effect over Gram-negative bacteria. However, no significant differences for the efficacy of all the 5 compounds were observed by 4 h. The three chitosans possessed a higher antimicrobial activity when impregnated onto the fabric, and presented a similar effect on both Gram-positive bacteria and yeast, in either matrix. Pseudomonas aeruginosa showed to be the most resistant microorganism to all five compounds. PMID:20208434

Fernandes, João C; Tavaria, Freni K; Fonseca, Susana C; Ramos, Oscar S; Pintado, Manuela E; Malcata, F Xavier

2010-02-01

219

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

220

Degradation of covalently cross-linked carboxymethyl chitosan and its potential application for peripheral nerve regeneration  

Microsoft Academic Search

Chitosan has been widely used in a variety of biomedical applications including peripheral nerve repair because of its excellent mechanical properties and biocompatibility. However, chitosan itself has a very slow degradation rate, and its molecules degrade in an uncontrollable manner. We hypothesized that the cross-linking of carboxymethyl chitosan (CM-chitosan), which is soluble in water, would result in a higher degradation

Guangyuan Lu; Lijun Kong; Baiyang Sheng; Gan Wang; Yandao Gong; Xiufang Zhang

2007-01-01

221

Novel naturally crosslinked electrospun nanofibrous chitosan mats for guided bone regeneration membranes: material characterization and cytocompatibility.  

PubMed

Guided bone regeneration (GBR) barrier membranes are used to prevent soft tissue infiltration into the graft space during dental procedures that involve bone grafting. Chitosan materials have shown promise as GBR barrier membranes, due to their biocompatibility and predictable biodegradability, but degradation rates may still be too high for clinical applications. In this study, chitosan GBR membranes were electrospun using chitosan (70% deacetylated, 312?kDa, 5.5?w/v%), with or without the addition of 5 or 10?mm genipin, a natural crosslinking agent, in order to extend the degradation to meet the clinical target time frame of 4-6?months. Membranes were evaluated for fibre diameter, tensile strength, biodegradation rate, bond structure and cytocompatibility. Genipin addition, at 5 or 10?mm, resulted in median fibre diameters 184, 144 and 154?nm for uncrosslinked, 5?mm and 10?mm crosslinked, respectively. Crosslinking, examined by Fourier transform infrared spectroscopy, showed a decrease in N-H stretch as genipin levels were increased. Genipin-crosslinked mats exhibited only 22% degradation based on mass loss, as compared to 34% for uncrosslinked mats at 16?weeks in vitro. The ultimate tensile strength of the mats was increased by 165% to 32?MPa with 10?mm crosslinking as compared to the uncrosslinked mats. Finally, genipin-crosslinked mats supported the proliferation of SAOS-2 cells in a 5?day growth study, similar to uncrosslinked mats. These results suggest that electrospun chitosan mats may benefit from genipin crosslinking and have the potential to meet clinical degradation time frames for GBR applications. Copyright © 2012 John Wiley & Sons, Ltd. PMID:23166109

Norowski, Peter A; Fujiwara, Tomoko; Clem, William C; Adatrow, Pradeep C; Eckstein, Eugene C; Haggard, Warren O; Bumgardner, Joel D

2012-11-20

222

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.

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

2012-01-01

223

Photo-polymeriable chitosan derivative prepared by Michael reaction of chitosan and polyethylene glycol diacrylate (PEGDA).  

PubMed

N-Alkyled photo-polymeriable chitosan derivative (PEGDA-CS) was synthesized by Michael reaction of chitosan and polyethylene glycol diacrylate (PEGDA) under mild reaction conditions. The chemical structure and physical properties of PEGDA-CS were characterized by FT-IR, (1)H NMR, XRD and TG techniques. The degree of substitution (DS) of PEGDA-CS could be calculated from (1)H NMR. PEGDA-CS exhibited good solubility in distilled water. XRD analysis showed that PEGDA-CS was amorphous. TG results demonstrated that thermal stability of the derivate was lower than that of chitosan. Antimicrobial test showed that PEGDA-CS had the antimicrobial activity on Escherichia coli. It could photopolymerize under ultraviolet light with 2959 as initiator. PMID:19720075

Ma, Guiping; Zhang, Xiaodan; Han, Jing; Song, Guoqiang; Nie, Jun

2009-12-01

224

Preparation and properties of photo-crosslinkable hydrogel based on photopolymerizable chitosan derivative.  

PubMed

Photopolymerizable chitosan derivative was synthesized by chitosan and methyl acroloyl glycine (MAG). The chemical structures and physical properties were characterized by FT-IR, (1)H NMR, XRD and TGA. The thermal stability of chitosan derivative was lower than chitosan. The chitosan derivative was amorphous compared with the high degree crystallization of chitosan. The hydrogels were prepared based on chitosan derivative via photopolymerization with different concentrations of photoinitiator 2959. The surface of hydrogel showed porous network and the pore size distribution tended to become homogeneous with the increase of the concentration of 2959, while the swelling property decreased due to more crosslinking. PMID:23142139

Qi, Zaiqian; Xu, Juan; Wang, Zhiliang; Nie, Jun; Ma, Guiping

2013-02-01

225

Preparation and characterization of water-soluble chitosan derivative by Michael addition reaction.  

PubMed

The efficient procedure to prepare novel water-soluble chitosan derivative was established by Michael addition reaction to introduce sodium allylsulfonate into the chitosan at mild condition. The chemical structure of the chitosan derivative was characterized by FT-IR, (1)H NMR and Elemental analysis. The degree of substitution (DS) was calculated by Elemental analysis. The chitosan derivative exhibited an excellent solubility in the distilled water. The physical properties were analyzed by XRD and TG. The XRD study indicated that the crystallinity of chitosan derivative decreased. The thermal analysis showed that chitosan derivative had lower thermal stability than chitosan. PMID:20837054

Jiang, Mingyan; Wang, Kemin; Kennedy, John F; Nie, Jun; Yu, Qiang; Ma, Guiping

2010-12-01

226

Immobilization of 5-fluorouridine on chitosan.  

PubMed

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

Malecki, Edith; Viere, Rebecca; Rosemeyer, Helmut

2013-10-01

227

Chitosan electrodeposition for microrobotic drug delivery.  

PubMed

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

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

2013-07-01

228

Chitosan based hydrogel microspheres as drug carriers.  

PubMed

Chitosan/tripolyphosphate (CHIT/TPP) and chitosan/tripolyphosphate/chondroitin sulfate (CHIT/TPP/CHS) core-shell type microspheres were prepared by polyelectrolyte complexation in order to develop a biocompatible matrix for drug delivery. The continual method using a multi-loop reactor under sterile conditions was applied for microsphere preparation. All the types of microspheres produced were spherical in shape and had a porous structure. The mechanical resistance of the microspheres increased in the presence of CHS as the second polyanion, which toughened the microsphere shell structure. For a drug release application, the process of microsphere preparation was modified by dissolving ofloxacin (OFL), the fluoroquinolone antibiotic, in CHIT solution before complex formation. This study shows the difference in OFL release comparing the microspheres CHIT/TPP and CHIT/TPP/CHS and implies the potential to control this process. PMID:17477445

Vodná, Lucia; Bubeníková, Silvia; Lacík, Igor; Chorvát, Dusan; Bakos, Dusan

2007-05-10

229

Chitosan microparticles incorporating a hydrophilic sunscreen agent  

Microsoft Academic Search

A microparticulate delivery system incorporating the hydrophilic sunscreen agent, phenylbenzimidazole sulphonic acid (PBSA) was prepared for better in-use performance. Chitosan, not adequately considered for sunscreen delivery, was used a matrix material. Emulsion crosslinking with glutaraldehyde generated microparticles (MPs) with good features in terms of yield (?76%), size (24–100?m) and % incorporation efficiency (29–74%). PBSA release was sustained over 8h according

Yasmine A. Gomaa; Labiba K. El-Khordagui; Nabila A. Boraei; Inas A. Darwish

2010-01-01

230

Thermogravimetric and FTIR studies of chitosan blends  

Microsoft Academic Search

Results of spectrophotometric and thermogravimetric studies of chitosan (CH) blends with polyvinyl alcohol (PVAL), starch (S) and hydroxypropylcellulose (HPC) obtained by casting from solutions in the form of transparent films containing 0–1.0 weight fraction of CH were discussed. Blends containing S are homogeneous only in the case of low-weight fraction of S (to 0.3).On the basis of results of thermodegradation

A Pawlak; M Mucha

2003-01-01

231

Enzymatic sequencing of partially acetylated chitosan oligomers.  

PubMed

Chitosan oligosaccharides have diverse biological activities with potentially valuable applications, for example, in the fields of medicine and agriculture. These functionalities are thought to depend on their degree of polymerization and acetylation, and possibly on specific patterns of acetylation. Chitosan oligomers with fully defined architecture are difficult to produce, and their complete analysis is demanding. Analysis is typically done using MS or NMR, requiring access to expensive infrastructure, and yielding unequivocal results only in the case of rather small oligomers. We here describe a simple and cost-efficient method for the sequencing of ?g amounts of chitosan oligosaccharides which is based on the sequential action of two recombinant glycosidases, namely an exo-?-N-acetylhexosaminidase (GlcNAcase) from Bacillus subtilis 168 and an exo-?-d-glucosaminidase (GlcNase) from Thermococcus kodakarensis KOD1. Starting from the non-reducing end, GlcNAcase and GlcNase specifically remove N-acetyl glucosamine (A) and glucosamine (D) units, respectively. By the sequential addition and removal of these enzymes in an alternating way followed by analysis of the products using high-performance thin-layer chromatography, the sequence of chitosan oligosaccharides can be revealed. Importantly, both enzymes work under identical conditions so that no buffer exchange is required between steps, and the enzyme can be removed conveniently using simple ultra-filtration devices. As proof-of-principle, the method was used to sequence the product of enzymatic deacetylation of chitin pentamer using a recombinant chitin deacetylase from Vibrio cholerae which specifically removes the acetyl group from the second unit next to the non-reducing end of the substrate, yielding mono-deacetylated pentamer with the sequence ADAAA. PMID:24824785

Hamer, Stefanie Nicole; Moerschbacher, Bruno Maria; Kolkenbrock, Stephan

2014-06-17

232

Complexation of chitosan with maleic acid copolymers  

Microsoft Academic Search

The complexation of chitosan with alternating copolymers of maleic acid with N-vinylpyrrolidone, ethylene, or styrene is studied. It is found that the process is of a cooperative character and that the\\u000a binding constants and the Hill parameters are dependent on the nature of a nonionogenic comonomer maleic acid in the synthetic\\u000a polyanion and on the conditions of complexation. The data

M. A. Krayukhina; N. A. Samoilova; A. S. Erofeev; I. A. Yamskov

2010-01-01

233

SORPTIVITY AND STRUCTURAL CHARACTERISTICS OF SPRAY-DRIED CHITOSAN MICROPARTICLES  

Microsoft Academic Search

Solid materials with a porous structure as a chitosan microparticles are very often applied where their sorption ability plays the main role. In this study, microparticles were formed by means of spray drying of two chitosan salts: acetate and ascorbate, and two cross-linking agents glutaraldehyde and sodium triphosphate were added to the solution. Dry microparticles as a product of different

Janusz Adamiec; Zofia Modrzejewska

234

Chitosan Supplementation and Fecal Fat Excretion in Men  

Microsoft Academic Search

Objective: Few weight loss supplements are clinically tested for efficacy, yet their proliferation continues. Chitosan-based supplements are sold as fat trappers and fat magnets. They purportedly block fat absorption and cause weight loss without food restriction. We quantified the in vivo effect of a chitosan product on fat absorption.Research Methods and Procedures: Participants (n = 15) consumed five meals per

Matthew D. Gades; Judith S. Stern

2003-01-01

235

Hierarchical structure and physicochemical properties of plasticized chitosan.  

PubMed

Plasticized chitosan with hierarchical structure, including multiple length scale structural units, was prepared by a "melt"-based method, that is, thermomechanical mixing, as opposed to the usual casting-evaporation procedure. Chitosan was successfully plasticized by thermomechanical mixing in the presence of concentrated lactic acid and glycerol using a batch mixer. Different plasticization formulations were compared in this study, in which concentrated lactic acid was used as protonation agent as well as plasticizer. The microstructure of thermomechanically plasticized chitosan was investigated by X-ray diffraction, scanning electron microscopy, and optical microscopy. With increasing amount of additional plasticizers (glycerol or water), the crystallinity of the plasticized chitosan decreased from 63.7% for the original chitosan powder to almost zero for the sample plasticized with additional water. Salt linkage between lactic acid molecules and amino side chains of chitosan was confirmed by FTIR spectroscopy: the lactic acid molecules expanded the space between the chitosan molecules of the crystalline phase. In the presence of other plasticizers (glycerol and water), various levels of structural units including an amorphous phase, nanofibrils, nanofibril clusters, and microfibers were produced under mechanical shear and thermal energy and identified for the first time. The thermal and thermomechanical properties of the plasticized chitosan were measured by thermogravimetric analysis, differential scanning calorimetric, and DMA. These properties were correlated with the different levels of microstructure, including multiple structural units. PMID:24564751

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

2014-04-14

236

Chitosan sponges as tissue engineering scaffolds for bone formation  

Microsoft Academic Search

Rat calvarial osteoblasts were grown in porous chitosan sponges fabricated by freeze drying. The prepared chitosan sponges had a porous structure with a 100–200 µm pore diameter, which allowed cell proliferation. Cell density, alkaline phosphatase activity and calcium deposition were monitored for up to 56 d culture. Cell numbers were 4 × 106 (day 1), 11 × 106 (day 28) and 12 ×

Yang-Jo Seol; Jue-Yeon Lee; Yoon-Jeong Park; Yong-Moo Lee; Young-Ku; In-Chul Rhyu; Seung-Jin Lee; Soo-Boo Han; Chong-Pyoung Chung

2004-01-01

237

Synthesis and characterization of oil-chitosan composite spheres.  

PubMed

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

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

2013-01-01

238

Synthesis and hydroxyl radicals scavenging activity of quaternized carboxymethyl chitosan  

Microsoft Academic Search

In order to determine the effect of the forms of the amido groups of chitosan on antioxidant activity, quaternized carboxymethyl chitosan (QCMC) derivatives were prepared with a degree of quaternization ranging from 34.3% to 59.5%. The antioxidant activity of QCMCs against hydroxyl radicals was assessed. The results indicated that QCMCs have better hydroxyl radicals scavenging activity than that of carboxymethyl

Zhanyong Guo; Ronge Xing; Song Liu; Zhimei Zhong; Pengcheng Li

2008-01-01

239

A new drug nanocarrier consisting of chitosan and hydoxypropylcyclodextrin  

Microsoft Academic Search

The objective of the present work was to develop a new drug nanocarrier consisting of nanoparticles made of chitosan and cyclodextrins. The rationale behind the design of this new nanosystem was to simultaneously implement the cyclodextrin drug complexation power and the inherent properties of chitosan nanoparticles, in a unique delivery system. The complexation with the cyclodextrin permits the solubilization as

Francesca Maestrelli; Marcos Garcia-Fuentes; Paola Mura; Maria José Alonso

2006-01-01

240

Biopolymer composite films based on ?-carrageenan and chitosan  

Microsoft Academic Search

Bioploymer composite films of ?-carrageenan and chitosan were prepared by co-dissolving ?-carrageenan and chitosan in several different organic acids. Tensile strength (TS), elongation (E), and water vapor permeability (WVP) were determined as a function of ascorbic acid added. Ascorbic acid tends to increase the properties of the films from all acids. Malic acid exhibited largest increase in tensile strength and

Sun Y. Park; Burtrand I. Lee; Soon T. Jung; Hyun J. Park

2001-01-01

241

Trimethyl chitosan nanoparticles enhances dissolution of the poorly water soluble drug Candesartan-Cilexetil  

Microsoft Academic Search

Candesartan-cilexetil, an angiotensin receptor blocker, exhibits low bioavailability after oral administration due to its low water solubility.\\u000a Chitosan is considered one of the most promising biopolymers for drug delivery as a vehicle and trimethyl chitosan is a water\\u000a soluble chitosan derivative. Trimethyl chitosan nanoparticles were prepared by the ionic crosslinking of a trimethyl chitosan\\u000a solution with tripolyphosphate, at ambient temperatures

Aylin Geçer; Nuray Y?ld?z; Ayla Çal?ml?; Belma Turan

2010-01-01

242

Studies on the photocatalytic performance of cuprous oxide\\/chitosan nanocomposites activated by visible light  

Microsoft Academic Search

Taking the chitosan nanoparticles prepared by adding only sodium sulfate into acetic acid solution of chitosan as carriers, cuprous oxide\\/chitosan nanocomposites were prepared by electrochemical deposition. It’s found that the needle shaped cuprous oxide nanocrystallines are combined with chitosan particles by chelation. Activated by a visible light, Cu2O\\/chitosan nanocomposites are used as a photocatalyst in the degradation of brilliant red

Jin-Yi Chen; Pei-Jiang Zhou; Jia-Lin Li; Yan Wang

2008-01-01

243

Thiolated Chitosan\\/DNA Nanocomplexes Exhibit Enhanced and Sustained Gene Delivery  

Microsoft Academic Search

Purpose  Thiolated chitosan appears to possess enhanced mucoadhesiveness and cell penetration properties, however, its potential in gene-drug delivery remains unknown. Herein, we report on a highly effective gene delivery system utilizing a 33-kDa thiol-modified chitosan derivative.Methods  Thiolated chitosan was prepared by the reaction with thioglycolic acid. Nanocomplexes of unmodified chitosan or thiolated chitosan with plasmid DNA encoding green fluorescenct protein (GFP) were

Dongwon Lee; Weidong Zhang; Shawna A. Shirley; Xiaoyuan Kong; Gary R. Hellermann; Richard F. Lockey; Shyam S. Mohapatra

2007-01-01

244

Properties of chitosan–collagen sponges and osteogenic differentiation of rat-bone-marrow stromal cells  

Microsoft Academic Search

The aim of this study was to further investigate effects of a combined chitosan and collagen matrix on osteogenic differentiation of rat-bone-marrow stromal cells (BMSCs), including analysis of the physical and mechanical properties of the sponges. There were 4 study groups: collagen, chitosan, 1:1 chitosan–collagen and 1:2 chitosan–collagen sponges. Chitosan–collagen sponges were fabricated using the freeze-drying technique. BMSCs were seeded

P. Arpornmaeklong; P. Pripatnanont; N. Suwatwirote

2008-01-01

245

Chemical characteristics of O-carboxymethyl chitosans related to the preparation conditions  

Microsoft Academic Search

Carboxymethyl chitosan (CM-chitosan) was prepared by chemical reaction with monochloroacetic acid under various conditions, and the chemical structure was analyzed by IR and NMR. The water solubility of the CM-chitosans had close relationships to the modifying conditions and the degree of carboxymethylation. The CM-chitosans, prepared at temperatures of 0–10 °C were soluble in water. But the CM-chitosan prepared between 20

Xi-Guang Chen; Hyun-Jin Park

2003-01-01

246

Carboxymethyl-chitosan protects rabbit chondrocytes from interleukin-1?-induced apoptosis  

Microsoft Academic Search

Chondrocyte apoptosis is important in pathogenesis of osteoarthritis. Chitosan is a non-toxic, biodegradable and biocompatible glycosaminoglycan. In this study, the effects of carboxymethyl-chitosan (CM-chitosan), a soluble derivative of chitosan, on chondrocyte apoptosis were investigated. Primary rabbit chondrocytes were cultured and induced to apoptosis by 10 ng\\/ml interleukin-1? (IL-1?). After treatment with various concentrations of CM-chitosan (50, 100, 200 ?g\\/ml), the apoptotic rate,

Qing Chen; Shi-Qing Liu; Yu-Ming Du; Hao Peng; Li-Ping Sun

2006-01-01

247

A novel mucoadhesive polymer prepared by template polymerization of acrylic acid in the presence of chitosan  

Microsoft Academic Search

A novel mucoadhesive polymer was prepared by template polymerization of acrylic acid in the presence of chitosan for transmucosal drug delivery system (TMD). FT-IR results indicated that polymer complex was formed between poly(acrylic acid) (PAA) and chitosan through hydrogen bonding. Glass transition temperature (Tg) of chitosan and PAA in the PAA\\/chitosan polymer complexes was inner-shifted compared with Tg of chitosan

Jae-Soon Ahn; Hoo-Kyun Choi; Chong-Su Cho

2001-01-01

248

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

249

Affinity chromatography of trypsin using chitosan as ligand support.  

PubMed

Chitosan beads were prepared for use as affinity adsorbent carrier. The affinity ligand, chicken ovomucoid, was immobilized on the chitosan via a cross-linker, glutaraldehyde. The results showed that 60 mg chicken ovomucoid could be immobilized on l g chitosan, and the maximum binding capacity for trypsin was about 8.10(4) U/g dry adsorbent. The procedure for preparing the chitosan-based affinity adsorbents was much safer and simpler than when a Sepharose-based matrix was the support. Columns packed with the affinity adsorbents were employed for trypsin chromatography. The experimental results revealed that the affinity adsorbents possessed good mechanical strength and storage stability and could be also operated repeatedly. Chitosan was suitable for use as an affinity adsorbent support for laboratory-scale and large-scale purification. PMID:8817887

Shi, Y C; Jiang, Y M; Sui, D X; Li, Y L; Chen, T; Ma, L; Ding, Z T

1996-08-23

250

Dairy Wastewater Treatment Using Low Molecular Weight Crab Shell Chitosan  

NASA Astrophysics Data System (ADS)

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

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

2012-08-01

251

Plasma Depolymerization of Chitosan in the Presence of Hydrogen Peroxide  

PubMed Central

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

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

2012-01-01

252

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

253

Antimicrobial textile treated with chitosan from Aspergillus niger mycelial waste.  

PubMed

The waste biomass of Aspergillus niger, following citric acid production, was used as a source for fungal chitosan extraction. The produced chitosan was characterized with deacetylation degree of 89.6%, a molecular weight of 25,000 dalton, 97% solubility in 1% acetic acid solution and comparable FT-IR spectra to standard shrimp chitosan. Fungal chitosan was applied as a cotton fabric finishing agent using pad-dry-cure method. The topographical structure of chitosan-treated fabrics (CTF) was much improved compared with control fabrics. CTF, after durability tests, exhibited a powerful antimicrobial activity against both E. coli and Candida albicans, the captured micrographs for E. coli cells contacted with CTF showed a complete lysis of cell walls with the prolonging contact time. The produced antimicrobial CTF could be proposed as a suitable material for many medical and hygienic applications. PMID:21596059

Tayel, Ahmed A; Moussa, Shaaban H; El-Tras, Wael F; Elguindy, Nihal M; Opwis, Klaus

2011-08-01

254

Development and optimization of curcumin-loaded mannosylated chitosan nanoparticles using response surface methodology in the treatment of visceral leishmaniasis.  

PubMed

Objective: The study aims at formulation and optimization of macrophage-targeted curcumin-loaded mannosylated chitosan nanoparticles (Cur-MCNPs) of curcumin (CUR) to improve its therapeutic potential in the treatment of visceral leishmaniasis (VL). Methods: Response surface methodology (RSM) using central composite design was employed to study the effect of formulation factors on physicochemical-dependent characteristics. Chitosan was coupled with d-mannose, by reductive amination, to prepare a mannosylated chitosan, a conjugate polymer and a subsequent formulation of Cur-MCNPs. Optimized formulation prepared using RSM was evaluated for in vitro release kinetics at physiological pH 7.4 and endosomal macrophage pH 4.5; in vivo pharmacokinetic profile and targeting potential were evaluated by fluorescence microscopy. Results: Optimized Cur-MCNPs exhibited spherical and smooth surface with a mean particle size of 215 nm, polydispersity index of 0.381, zeta potential of + 24.37 mV and % entrapment efficiency of 82.12%. The pharmacokinetic study of optimized Cur-MCNPs showed significant improvement in the value of mean resident time (39.38 h) compared to free CUR solution (0.30 h) (p < 0.05). In vivo uptake study indicated that endocytosis took place effectively within the macrophages of reticuloendothelial system. Conclusions: Thus, Cur-MCNPs could be considered as a promising delivery strategy towards active targeting of CUR to macrophages for the effective treatment of VL. PMID:24875148

Chaubey, Pramila; Patel, Ravi R; Mishra, Brahmeshwar

2014-08-01

255

Novel chitosan-spotted alginate fibers from wet-spinning of alginate solutions containing emulsified chitosan-citrate complex and their characterization.  

PubMed

The major problem associated with the production of alginate/chitosan hybridized fibers by wet spinning is the formation of gels due to ionic interactions of the oppositely charged molecules of alginate and chitosan when these two polymers are directly mixed. Here, we proposed a novel method of using chitosan in the form of an emulsion. The emulsion was prepared by adding a primary emulsion of olive oil in a sodium dodecyl sulfate (SDS) aqueous solution into a chitosan-citrate complex. The complexation of chitosan with citric acid is the key of this method. The citrate ions neutralize the positive charges of chitosan, rendering the chitosan-citrate complex to readily penetrate into the core of the SDS/olive oil micelles. The obtained emulsified chitosan-citrate complex (hereafter, the chitosan-citrate emulsion) of varying amount was then added into an alginate aqueous solution to prepare the alginate/chitosan spinning dope suspensions. The alginate/chitosan hybridized fibers showed spotty features of the emulsified chitosan-citrate complex particles locating close to the surface and the inside of the hybridized fibers. At the lowest content of incorporated chitosan (i.e., 0.5% w/w chitosan), both the tenacity and the elongation at break of the obtained chitosan-spotted alginate fibers were the greatest. Further increase in the chitosan content resulted in a monotonous decrease in the property values. Lastly, preliminary studies demonstrated that the obtained chitosan-spotted alginate fibers showed great promises as carriers for drug delivery. PMID:19072144

Watthanaphanit, Anyarat; Supaphol, Pitt; Furuike, Tetsuya; Tokura, Seiichi; Tamura, Hiroshi; Rujiravanit, Ratana

2009-02-01

256

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

PubMed

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

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

2009-01-01

257

Chitosan dermal substitute and chitosan skin substitute contribute to accelerated full-thickness wound healing in irradiated rats.  

PubMed

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

258

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

259

Spectrum and mechanisms of inflammasome activation by chitosan.  

PubMed

Chitosan, the deacetylated derivative of chitin, can be found in the cell wall of some fungi and is used in translational applications. We have shown that highly purified preparations of chitosan, but not chitin, activate the NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome in primed mouse bone marrow-derived macrophages (BMM?), inducing a robust IL-1? response. In this article, we further define specific cell types that are activated and delineate mechanisms of activation. BMM? differentiated to promote a classically activated (M1) phenotype released more IL-1? in response to chitosan than intermediate or alternatively activated macrophages (M2). Chitosan, but not chitin, induced a robust IL-1? response in mouse dendritic cells, peritoneal macrophages, and human PBMCs. Three mechanisms for NLRP3 inflammasome activation may contribute: K(+) efflux, reactive oxygen species, and lysosomal destabilization. The contributions of these mechanisms were tested using a K(+) efflux inhibitor, high extracellular potassium, a mitochondrial reactive oxygen species inhibitor, lysosomal acidification inhibitors, and a cathepsin B inhibitor. These studies revealed that each of these pathways participated in optimal NLRP3 inflammasome activation by chitosan. Finally, neither chitosan nor chitin stimulated significant release from unprimed BMM? of any of 22 cytokines and chemokines assayed. This study has the following conclusions: 1) chitosan, but not chitin, stimulates IL-1? release from multiple murine and human cell types; 2) multiple nonredundant mechanisms appear to participate in inflammasome activation by chitosan; and 3) chitin and chitosan are relatively weak stimulators of inflammatory mediators from unprimed BMM?. These data have implications for understanding the nature of the immune response to microbes and biomaterials that contain chitin and chitosan. PMID:24829412

Bueter, Chelsea L; Lee, Chrono K; Wang, Jennifer P; Ostroff, Gary R; Specht, Charles A; Levitz, Stuart M

2014-06-15

260

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

PubMed Central

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

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

2011-01-01

261

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

PubMed Central

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

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

2012-01-01

262

Development and characterization of LTA-appended chitosan nanoparticles for mucosal immunization against hepatitis B.  

PubMed

Abstract The present study was aimed at exploring the targeting potential of LTA-anchored chitosan nanoparticles (CH-NP) specifically to M cell following oral immunization. The lectinized CH-NP exhibited 7-29% coupling capacity depending upon the amount of glutaraldehyde added. Induction of the mucosal immunity was assessed by estimating secretory IgA level in the salivary, intestinal and vaginal secretions, and cytokine (IL-2 and IFN-?) levels in the spleen homogenates. The results demonstrated that LTA-anchored CH-NP elicited strong humoral and cellular responses and hence could be a competent carrier-adjuvant delivery system for oral mucosal immunization against Hepatitis B. PMID:23815286

Mishra, Neeraj; Khatri, Kapil; Gupta, Madhu; Vyas, Suresh P

2014-08-01

263

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

PubMed

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

Jung, Jooyeoun; Zhao, Yanyun

2013-09-18

264

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

265

[Effect of chitosan derivatives on the reproduction of Coliphages T2 and T7].  

PubMed

The effect of chitosan derivatives with different degrees of polymerization and deamination, as well as of chitosan 6-O-sulfate and chitosan N-succinate-6-O-sulfate, on the reproduction of coliphages T2 and T7 in Escherichia coli and on the growth of this bacterium was studied. Chitosan derivatives decreased the yield of coliphages and exhibited bactericidal activity. The efficiency of inhibition of viral infection and the bactericidal activity of chitosan were found to be dependent on the degree of its polymerization. At the same time, there was no correlation between the degree of chitosan deamination and the extent of inhibition of viral infection. Anionic chitosan derivatives virtually did not possess antiviral or bactericidal activity. It is assumed that chitosan blocks some stages of phage reproduction. The decrease in the phage-producing ability of E. coli may also be due to the bactericidal effect of chitosan. PMID:10776627

Kochkina, Z M; Chirkov, S N

2000-01-01

266

Antimicrobial characteristics of chitosans against food spoilage microorganisms in liquid media and mayonnaise.  

PubMed

Four different kinds of chitosans were prepared by treating crude chitin with various NaOH concentrations. The antimicrobial activities of the chitosans were tested against four species of food spoilage microorganisms (Lactobacillus plantarum, Lactobacillus fructivorans, Serratia liquefaciens, and Zygosaccharomyces bailii). The initial effect of the chitosans was biocidal, and counts of viable cells were significantly reduced. After an extended lag phase, some strains recovered and resumed growth. The activities of chitosan against these microorganisms increased with the concentration. Chitosan-50 was most effective against L. fructivorans, but inhibition of L. plantarum was greatest with chitosan-55. There was no significant difference among the chitosans in their antimicrobial activity against S. liquefaciens and Z. bailii. The addition of chitosan to mayonnaise significantly decreased the viable cell counts of L. fructivorans and Z. bailii during storage at 25 degrees C. These results suggest that chitosan can be used as a food preservative to inhibit the growth of spoilage microorganisms in mayonnaise. PMID:11791708

Oh, H I; Kim, Y J; Chang, E J; Kim, J Y

2001-11-01

267

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

268

Transglutaminase-catalyzed grafting collagen on chitosan and its characterization.  

PubMed

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

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

2014-05-25

269

Fungal mycelium--the source of chitosan for chromatography.  

PubMed

Mycelium of the mold Aspergillus niger was used as a raw material for the preparation of microbial chitosan. Aspergillus niger, the mold used for the production of citric acid, contains approx. 15% of chitin, which can be separated, transformed into chitosan, and used as a sorbent for chromatography. The main advantage of this material in comparison with krill chitosan is the uniformity of particle size leading to the low back-pressure in the column. The other advantage is the fact, that original fibrous structure of mycelial pellets could be stabilized before chitosan preparation by cross-linking with glutaraldehyde. The product prepared by this way -- crosslinked chitosan of uniform particle size, is highly porous, with high water regain and, as a result, low sedimentation velocity. Low sedimentation velocity is not disadvantage in chromatographic application, but may form some problems in batchwise operation. Chitosan as a polymer of glucosamine is anion exchanger in nature and the chromatographic properties of this anion exchanger was demonstrated by the chromatography of bovine blood plasma, glucose oxidase, and chicken pepsinogen. In all cases, the course of chromatography on crosslinked chitosan was compared with the chromatography on MONO Q (bovine blood plasma) or DEAE-cellulose (glucose oxidase, chicken pepsinogen) under the same protocol. PMID:15236688

Kucera, Jiri

2004-08-25

270

Protective effect of chitosan treatment against acetaminophen-induced hepatotoxicity.  

PubMed

Acetaminophen (APAP) is the most commonly reported toxic ingestion in the world. Severe liver injury resulting from overdose or chronic use of APAP remains a significant clinical problem. In recent years, the mechanisms underlying liver injury caused by APAP have become much better understood. We have studied the protective effect of chitosan supplementation against APAP-induced hepatotoxicity with respect to changes in the levels of total and lipid-bound sialic acid in the serum and in the liver tissue and changes in the activity of diagnostic marker enzymes, lipid peroxidation, and ceruloplasmin oxidase enzyme in normal and experimental groups of rats. During the experimental period, chitosan (200 mg/kg body weight per day) was administered to APAP + chitosan-treated rats by oral gavage. Results showed that treatment with APAP induced a significant increase in the serum alanine aminotransferase and alkaline phosphatase activities, in total and lipid-bound sialic acids levels, and in the liver lipid peroxide content. The administration of chitosan significantly prevented APAP-induced alterations in the levels of diagnostic marker enzymes, total sialic acid, lipid-bound sialic acid, and malondialdehyde in the experimental groups of rats. Furthermore, chitosan administration increased the activity of ceruloplasmin oxidase. In conclusion, our results suggest that chitosan has a protective effect on APAP-induced hepatic injury in rats. The study sheds light on the therapeutic potential of chitosan in an APAP-induced hepatotoxicity model. PMID:24835348

Ozcelik, Eda; Uslu, Sema; Erkasap, Nilufer; Karimi, Hadi

2014-06-01

271

Physicochemical and biofunctional properties of crab chitosan nanoparticles.  

PubMed

The physicochemical and biofunctional properties of crab chitosan nanoparticles of two different sizes (Nano A and B) manufactured by dry milling method were evaluated for commercialization. The deacetylation degrees (DD) of Nano A, B and the control chitosan were 90.9, 93.0, and 92.7% respectively whereas their molecular weights (M(w)) were 43.9, 44.7 and 208.8 kDa. The average sizes of the dispersed Nano A, B and the control chitosan in cetyltrimethylammonium chloride were 735.9, 849.4 and 2,382.4 nm, respectively, which were lower than 1441.7, 2935.6 and 6832.9 nm of the intact chitosans. Chitosan nanoparticles had mild tyrosinase, antioxidant and angiotensin I converting enzyme (ACE), but weak collagenase, elastase and beta-glucuronidase inhibitory activity. However, Nano A had strong alpha-glucosidase inhibitory activity, which was comparable to that of acarbose, a commercial alpha-glucosidase inhibitor. In addition, the minimum inhibitory concentrations (MICs) of chitosan and its nanoparticles ranged from 30 to > 200 microg/mL against each four gram-positive and gram-negative bacteria. Therefore, crab chitosan nanoparticles could be used as a nutraceutical, cosmeceutical or pharmaceutical product. PMID:23882757

Nguyen, The Han; Kwak, Hae Soo; Kim, Sang Moo

2013-08-01

272

Chitosan-based nanofibrous membranes for antibacterial filter applications  

PubMed Central

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/hr/m2) 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.

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

2013-01-01

273

Ultrastructure of hybrid chitosan-glycerol phosphate blood clots by environmental scanning electron microscopy.  

PubMed

Chitosan-based polymers have been extensively studied for biomedical applications. Recently, liquid solutions of chitosan in a glycerol phosphate buffer (chitosan-GP) with physiological pH and osmolality were mixed with autologous blood to form hybrid chitosan-GP/blood implants that improved the repair of articular cartilage lesions in a large animal model. The mixture of chitosan-GP and blood forms a viscous liquid, which solidifies in minutes via normal blood coagulation as well as chitosan-mediated mechanisms. Here we have examined the ultrastructure of these chitosan-GP/blood clots as well as regular blood clots and chitosan-GP gels, the latter produced by heating. Both unfixed and fixed samples of chitosan-GP/blood clots, regular blood clots, and chitosan-GP gels were investigated by environmental scanning electron microscopy (ESEM) in conjunction with energy dispersive X-ray spectrometry (EDS), the former permitting direct observation of the ultrastructure in hydrated conditions simulating the natural state. By examination of unfixed specimens using ESEM we found that chitosan formed a network structure in both chitosan-GP gels and chitosan-GP/blood clots; however this structure was altered by aldehyde fixation to produce artifactual aggregates of chitosan microparticles. We were also able to identify chitosan in chitosan-GP/blood clots by washing samples in low concentration NaCl solutions followed by local EDS analyses to identify excess chloride versus sodium, and thus presence of cationic chitosan in analyzed features. Additional results indicated that the majority of glycerol phosphate diffuses freely from chitosan-GP gels (by EDS of phosphorus) and that hyperosmotic paraformaldehyde-based fixatives (i.e. 4% w/v) significantly disturb erythrocyte morphology in fixed whole blood clots. PMID:18041781

Iliescu, M; Hoemann, C D; Shive, M S; Chenite, A; Buschmann, M D

2008-03-01

274

Lanthanum carbonate incorporated chitosan microparticles for phosphate collection  

Microsoft Academic Search

Lanthanum carbonate incorporated chitosan microparticles (LCCM) is proposed for collection of phosphate from 0.9% saline and human plasma serum samples. Loading of ?4.1mg of La2(CO3)3·3H2O onto 0.1g of chitosan has been achieved. The optimal glutaraldehyde (cross-linker), acetic acid concentration and lanthanum carbonate to chitosan weight ratio for preparation of LCCM were found to be 84.6–85.7%, 0.3–0.4moll?1, and 1:1 respectively. Moreover,

P. K. Aneesh; K. P. Prathish; R. Kala; T. Prasada Rao

2009-01-01

275

[Brucine chitosan thermosensitive hydrogel for intra-articular injection].  

PubMed

The aim of this study was to develop a sustained release converse thermosensitive hydrogel for intra-articular injection using chitosan-glycerol-borax as matrix, its physical properties and biocompatibility were investigated. Taking gelation time and gelation condition as index, the influence of concentration of chitosan, ratio of chitosan to glycerol, pH on physical properties of hydrogel were investigated. And then the in vitro drug release, rheological properties and biocompatibility were studied. The thermosensitive hydrogel flows easily at room temperature and turns to gelation at body temperature, which can certainly prolong the release of drug and has good biocompatibility. PMID:22812012

Chen, Zhi-Peng; Liu, Wen; Chen, Hong-Xuan; Cai, Bao-Chang

2012-05-01

276

Laser based fabrication of chitosan mediated silver nanoparticles  

NASA Astrophysics Data System (ADS)

We report fabrication of silver nanoparticles (Ag NPs) by laser ablation technique in different concentrations of aqueous chitosan solution. The ablation process of silver plate was carried out by using a nanosecond Q-switched Nd:YAG pulsed laser and the characterization of Ag NPs was done by Transmission electron microscopy, UV-Vis spectroscopy, and X-ray diffraction. UV-visible plasmon absorption spectra revealed that the formation efficiency as well as the stability of nanoparticles was increased by addition of chitosan. On the other hand, the size decrement of nanoparticles was more remarkable in the higher chitosan concentration.

Zamiri, Reza; Azmi, B. Z.; Naseri, Mahmoud Goodarz; Ahangar, Hossein Abbastabar; Darroudi, Majid; Nazarpour, Forough Kalaei

2011-10-01

277

Chitosan derivatives as biosorbents for basic dyes.  

PubMed

The scope of this study was to prepare and evaluate chitosan derivatives as biosorbents for basic dyes. This was achieved by grafting poly (acrylic acid) and poly (acrylamide) through persulfate induced free radical initiated polymerization processes and covalent cross-linking of the prepared materials. Remacryl Red TGL was used as the cationic dye. Equilibrium sorption experiments were carried out at different pH and initial dye concentration values. The experimental equilibrium data for each adsorbent-dye system were successfully fitted to the Langmuir, Freundlich and pH-dependent Langmuir-Freundlich sorption isotherms. Thermodynamic parameters of the adsorption process such as DeltaG degrees, DeltaH degrees, and DeltaS degrees were calculated. The negative values of free energy reflected the spontaneous nature of adsorption. The typical dependence of dye uptake on temperature and the kinetics of adsorption indicated the process to be chemisorption. The grafting modifications greatly enhanced the adsorption performance of the biosorbents, especially in the case of powdered cross-linked chitosan grafted with acrylic acid, which exhibited a maximum adsorption capacity equal to 1.068 mmol/g. Kinetic studies also revealed a significant improvement of sorption rates by the modifications. Diffusion coefficients of the dye molecule were determined to be of the order 10(-13) - 10(-12) m2/s. Furthermore, desorption experiments affirmed the regenerative capability of the loaded material. PMID:17530870

Lazaridis, Nikolaos K; Kyzas, George Z; Vassiliou, Alexandros A; Bikiaris, Dimitrios N

2007-07-01

278

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.

Lorkowska-Zawicka, Barbara; Kaminski, Kamil; Ciejka, Justyna; Szczubialka, Krzysztof; Bialas, Magdalena; Okon, Krzysztof; Adamek, Dariusz; Nowakowska, Maria; Jawien, Jacek; Olszanecki, Rafal; Korbut, Ryszard

2014-01-01

279

Chitosan adhesive for laser tissue repair  

NASA Astrophysics Data System (ADS)

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

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

2006-03-01

280

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

PubMed Central

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

2013-01-01

281

Physicochemical characteristics and antioxidant efficacy of chitosan from the internal shell of spineless cuttlefish Sepiella inermis.  

PubMed

Cuttlefish chitosan was extracted from the cuttlebone of Sepiella inermis by demineralization and deproteinization and produced by deacetylation, and its physical and chemical parameters were also compared with that of commercial chitosan. Ash, moisture, and mineral and metal content of the chitosan was estimated by adopting standard methodologies. The rate of deacetylation was calculated as 79.64% by potentiometric titration. Through viscometry and gel permeation chromatography, the molecular weight of chitosan was found to be significantly lower than that of the commercial chitosan. Optical activity was found to be levorotatory. The structure of the chitosan was elucidated with spectral techniques such as Fourier-transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy. Cuttlefish chitosan showed a melting endothermic peak at 117.32 °C. The x-ray diffraction (XRD) pattern of chitosan and standard chitosan exhibited the same crystalline peaks. Through scanning electron microscopy (SEM) the fine structure of chitosan was studied. The binding capacity (water and fat) of cuttlefish chitosan was found to be significantly higher than that of the commercial chitosan. The antioxidant efficacy of chitosan was determined through the conjugated diene method, scavenging ability on DPPH radicals, reducing power, and chelating ability on ferrous ions. This study has brought out the importance of shell as a potential source for obtaining another natural antioxidant. PMID:23768114

Vairamani, Shanmugam; Subhapradha, Namasivayam; Ramasamy, Pasiyappazham; Raveendran, Sankariah; Srinivasan, Alagiri; Shanmugam, Annaian

2013-01-01

282

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

PubMed

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

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

2014-04-01

283

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 5mg/L of chitosan, separation efficiency of >93% microalgae cells was found at 20mg/L of saponin. Removal efficiency of >54.4% and >73.0% was found for polysaccharide and protein, respectively at 20mg/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

284

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

PubMed

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

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

2013-10-01

285

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

286

Structural and rheological properties of chitosan semi-interpenetrated networks.  

PubMed

The local structure and the viscoelastic properties of semi-interpenetrated biopolymer networks based on cross-linked chitosan and poly(ethylene oxide) (PEO) were investigated by Small Angle Neutron Scattering and rheological measurements. The specific viscosity and the entanglement concentration of chitosan were first determined, respectively, by capillary viscosimetry and steady-state shear rheology experiments performed at different polymer concentrations. Mechanical spectroscopy was then used to study the gelation process of chitosan/PEO semi-interpenetrated networks. By fitting the frequency dependence of the elastic and loss moduli with extended relations of relaxation shear modulus around the sol-gel transition, it was shown that the addition of PEO chains had a significant effect on the viscoelastic properties of aqueous chitosan networks but no effect on the gelation time. The improvement of mechanical properties was in accordance with the correlation length decrease deduced from Small Angle Neutron Scattering experiments. PMID:20526647

Payet, L; Ponton, A; Grossiord, J-L; Agnely, F

2010-06-01

287

Microstructure and Properties of Polyhydroxybutyrate-Chitosan-Nanohydroxyapatite Composite Scaffolds  

PubMed Central

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

Medvecky, L.

2012-01-01

288

Propranolol hydrochloride release behaviour of crosslinked chitosan membranes.  

PubMed

Chitosan membranes of 20 microns thickness were prepared by a solvent evaporation technique and crosslinked with different concentrations of glutaraldehyde to obtain membranes of various degrees of crosslinking. These membranes were characterized by thermogravimetric (TG) analysis, differential scanning calorimetry (DSC) and tensile strength studies. The effect of crosslinking on the permeability of membranes to propranolol hydrochloride was evaluated by permeation studies conducted in static glass diffusion cells. A decrease in the thermal stability of chitosan membranes due to crosslinking was observed. The tensile strength of the membranes was improved by crosslinking. The introduction of crosslink points within the membrane reduced its permeability to propranolol hydrochloride as evidenced by decreased permeability and diffusion coefficients. Permeability studies revealed the operation of a pore mechanism in the transport of hydrophilic agents such as propranolol hydrochloride through chitosan and crosslinked chitosan membranes. PMID:7764115

Thacharodi, D; Rao, K P

1993-01-01

289

Chitosan macroporous foams obtained in highly concentrated emulsions as templates.  

PubMed

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

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

2013-11-15

290

S-protected thiolated chitosan: Synthesis and in vitro characterization  

PubMed Central

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

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

2012-01-01

291

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

292

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

PubMed

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

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

2014-02-15

293

Emerging chitin and chitosan nanofibrous materials for biomedical applications.  

PubMed

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. PMID:25000536

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

2014-07-24

294

pH dependent reversible aggregation of Chitosan and glycol-Chitosan stabilized silver nanoparticles  

NASA Astrophysics Data System (ADS)

Aggregation behaviour of Chitosan and glycol-Chitosan stabilized silver nanoparticles was investigated over the pH range of 3.4-13. With increasing pH, the charge of the particle reduces and approaches zero beyond 6.5 (the p Ka of the amino group) inducing aggregation that was confirmed by absorption spectroscopy, hyper-Rayleigh scattering (HRS) and TEM measurements. Interestingly the HRS intensity increased till pH 9.0 ± 2.0 and beyond this it dropped dramatically. This correlated with the formation of centrosymmetric spherical aggregates as evidenced by TEM pictures. The aggregation process was found to be reversible over at least 10 pH cycles by absorption and HRS measurements.

Saini, R. K.; Srivastava, A. K.; Gupta, P. K.; Das, K.

2011-08-01

295

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

296

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

297

SOLVENT PURIFICATION AND FLUOR SELECTION FOR GADOLINIUM-LOADED LIQUID SCINTILLATORS  

SciTech Connect

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

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

2007-01-01

298

Chitosan as template for the synthesis of ceria nanoparticles  

Microsoft Academic Search

Cerium oxide (CeO2), nanoparticles were prepared using chitosan as template, cerium nitrate as a starting material and sodium hydroxide as a precipitating agent. The resultant ceria–chitosan spheres were calcined at 350°C. The synthesized powders were characterized by, XRD, HRTEM, UV–vis, FTIR, and TG-DTA. The average size of the nanoparticles obtained was ?4nm and BET specific surface area ?105m2g?1. Blueshifts in

A. B. Sifontes; G. Gonzalez; J. L. Ochoa; L. M. Tovar; T. Zoltan; E. Cañizales

2011-01-01

299

Structure and properties of bilayer chitosan–gelatin scaffolds  

Microsoft Academic Search

Chitosan–gelatin hybrid polymer network scaffolds were prepared via the freeze-drying technique by using the ice microparticle as a porogen. Monolayer and bilayer scaffolds were obtained by using different pre-freezing methods. The novel bilayer scaffolds were prepared via contact with ?56°C lyophilizing plate directly, then lyophilized. The properties of chitosan–gelatin scaffolds, such as microstructure, physical and mechanical and degradable properties, were

Jin Shu Mao; Li Guo Zhao; Yu Ji Yin; Kang De Yao

2003-01-01

300

Feasibility study of chitosan as intravitreous tamponade material  

Microsoft Academic Search

Background  Chitosan can inhibit fibroblastic proliferation by suppressing fibroblast cells, and has the similar physiological characteristics\\u000a as normal vitreous body, so it might have the potential to become vitreous filling material and might possibly inhibit proliferative\\u000a vitreous retinopathy. To investigate the possibility of chitosan as vitreous filling material, this study was designed to\\u000a investigate retina, ciliary body, lens and cornea morphology

Hong Yang; Rong Wang; Qisheng Gu; Xiaonong Zhang

2008-01-01

301

Sodium iodide added chitosan electrolyte film for polymer batteries  

Microsoft Academic Search

Films of chitosan containing sodium iodide were prepared by the solution cast technique. Several films were prepared by dissolving 1 g of chitosan in different 100 ml of 1% acetic acid solution to which 0.5 g, 1.0 g, 1.5 g, 2.0 g and 2.5 g of sodium iodide was added. The electric conductivity of the films measured at room temperature

R H Y Subban; A K Arof

1996-01-01

302

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; Caro Rodríguez, Diana; Borkovec, Michal

2014-05-01

303

Characterization of chitosan–polycaprolactone blends for tissue engineering applications  

Microsoft Academic Search

The objective of this work was to study the effect of blending chitosan with poly(?-caprolactone) (PCL) on their biomechanical properties. After testing the effect of molecular weight (MW), temperature, and humidity on the tensile properties in dry, wet at 25°C and wet at 37°C conditions, chitosan with a MW>310kD was selected for use in the blend. Homogeneous blends of 25%,

Aparna Sarasam; Sundararajan V. Madihally

2005-01-01

304

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

305

Antibacterial activity of chitosan-based matrices on oral pathogens.  

PubMed

Chitosan is a well sought-after polysaccharide in biomedical applications due to its biocompatibility, biodegradability to non-toxic substances, and ease of fabrication into various configurations. However, alterations in the anti-bacterial properties of chitosan in various forms is not completely understood. The objective of this study was to evaluate the anti-bacterial properties of chitosan matrices in different configurations against two pathogens-Gram-positive Streptococcus mutans and Gram-negative Actinobacillus actinomycetemcomitans. Two-dimensional (2-D) membranes and three-dimensional (3-D) porous scaffolds were synthesized by air drying and controlled-rate freeze drying. Matrices were suspended in bacterial broths with or without lysozyme (enzyme that degrades chitosan). Influences of pore size, blending with Polycaprolactone (PCL, a synthetic polymer), and neutralization process on bacterial proliferation were studied. Transient changes in optical density of the broth, adhesion characteristics, viability, and contact-dependent bacterial activity were assessed. 3-D porous scaffolds were more effective in reducing the proliferation of S. mutans in suspension than 2-D membranes. However, no significant differences were observed on the proliferation of A. actinomycetemcomitans. Presence of lysozyme significantly increased the antibacterial activity of chitosan against A. actinomycetemcomitans. Pore size did not affect the proliferation kinetics of either species, with or without lysozyme. NaOH neutralization of chitosan increased bacterial adhesion whereas ethanol neutralization inhibited adhesion without lowering proliferation. Mat culture tests indicated that chitosan does not allow proliferation on its surface and it loses antibacterial activity upon blending with PCL. Results suggest that the chemical and structural characteristics of chitosan-based matrices can be manipulated to influence the interaction of different bacterial species. PMID:17701312

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

2008-03-01

306

[Preparation and biological evaluation of PLA/chitosan composite materials].  

PubMed

Hypersusceptibility test, pyrogen test, cell cultivation, and toxicity examination were applied in the biological evaluation of the poly(lactic acid) (PLA)/chitosan composite materials. The results indicated that all the materials were negative, conforming to the ISO10993-1. The cell could grow well on the surface of the materials. So the PLA/chitosan composite materials have good biocompatibility and can be planted in the body as scaffolds. PMID:14564997

Li, Lihua; Ding, Shan; Zhou, Changren

2003-09-01

307

Synthesis and characterization of chitosan–poly(acrylic acid) nanoparticles  

Microsoft Academic Search

Chitosan (CS)–poly(acrylic acid) (PAA) complex nanoparticles, which are well dispersed and stable in aqueous solution, have been prepared by template polymerization of acrylic acid (AA) in chitosan solution. The physicochemical properties of nanoparticles were investigated by using size exclusion chromatography, FT-IR, dynamic light scattering, transmission electron microscope and zeta potential. It was found that the molecular weight of PAA in

Yong Hu; Xiqun Jiang; Yin Ding; Haixiong Ge; Yuyan Yuan; Changzheng Yang

2002-01-01

308

Chitosan as a growth stimulator in orchid tissue culture  

Microsoft Academic Search

The effect of shrimp and fungal chitosan on the growth and development of orchid plant meristemic tissue in culture was investigated in liquid and on solid medium. The growth of meristem explants into protocorm-like bodies in liquid medium was accelerated up to 15 times in the presence of chitosan oligomer, the optimal concentration being 15ppm. The 1kDa shrimp oligomer was

Khin Lay Nge; Nitar Nwe; Suwalee Chandrkrachang; Willem F. Stevens

2006-01-01

309

Adsorption of acid dyes on chitosan—equilibrium isotherm analyses  

Microsoft Academic Search

The ability of chitosan, derived from deacetylated crab shell chitin, to remove acid dyes from effluent solution by adsorption has been studied. Equilibrium isotherms for the adsorption of five acid dyes, Acid Green 25 (AG25), Acid Orange 10 (AO10), Acid Orange 12 (AO12), Acid Red 18 (AR18) and Acid Red 73 (AR73), on chitosan were measured experimentally. Results were analysed

Y. C. Wong; Y. S. Szeto; W. H. Cheung; G. McKay

2004-01-01

310

Flocculation of kaolinite suspensions in water by chitosan  

Microsoft Academic Search

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

Ravi Divakaran; V. N Sivasankara Pillai

2001-01-01

311

Preparation and properties of alginate\\/carboxymethyl chitosan blend fibers  

Microsoft Academic Search

Alginate\\/carboxymethyl chitosan blend fibers, prepared by spinning their mixture solution through a viscose-type spinneret into a coagulating bath containing aqueous CaCl2, were studied for structure and properties with the aid of infrared spectroscopy (IR), X-ray diffraction (XRD) and scanning electron micrography (SEM). The analyses indicated a good miscibility between alginate and carboxymethyl chitosan, because of the strong interaction from the

Lihong Fan; Yumin Du; Baozhong Zhang; Jianhong Yang; Jinping Zhou; John F. Kennedy

2006-01-01

312

Nanofibrous membranes from aqueous electrospinning of carboxymethyl chitosan  

Microsoft Academic Search

Carboxymethyl chitosan (CMCS) with varying molecular weights (Mv = 40-405 kDa) and degrees of substitution (DS = 0.25-1.19) has been synthesized by alkalization of chitosan, followed by carboxymethylation with monochloroacetic acid. At DS up to 1.19, the locations where carboxymethylation took place were influenced by the alkalization temperature, i.e., both C2 and C6 substitution at ambient temperature (N,O-carboxymethylated) and mainly

Jian Du; You-Lo Hsieh

2008-01-01

313

Electrophoretic deposition of composite hydroxyapatite-chitosan coatings  

Microsoft Academic Search

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,

Xin Pang; Igor. Zhitomirsky

2007-01-01

314

Hydrophobically modified chitosan\\/gold nanoparticles for DNA delivery  

Microsoft Academic Search

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

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

2008-01-01

315

Swelling studies of chitosan\\/cashew nut gum physical gels  

Microsoft Academic Search

Gels from chitosan\\/cashew nut gum (CH\\/CNG) were prepared with different chitosan to cashew nut gum ratio and their swelling behaviour was investigated as a function of pH and salt. Infrared and Carbon-13 nuclear magnetic resonance spectroscopy were used to elucidate the gel structure. Swelling in water diminishes sharply when the ratio CH\\/CNG increases. In the presence of Na+ counterions the

Haroldo C. B Paula; Francisco J. S Gomes; Regina C. M de Paula

2002-01-01

316

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

317

A mechanistic based approach for enhancing buccal mucoadhesion of chitosan.  

PubMed

Mucoadhesive buccal drug delivery systems can enhance rapid drug absorption by providing an increased retention time at the site of absorption and a steep concentration gradient. An understanding of the mechanisms behind mucoadhesion of polymers, e.g. chitosan, is necessary for improving the mucoadhesiveness of buccal formulations. The interaction between chitosan of different chain lengths and porcine gastric mucin (PGM) was studied using a complex coacervation model (CCM), isothermal titration calorimetry (ITC) and a tensile detachment model (TDM). The effect of pH was assessed in all three models and the approach to add a buffer to chitosan based drug delivery systems is a means to optimize and enhance buccal drug absorption. The CCM demonstrated optimal interactions between chitosan and PGM at pH 5.2. The ITC experiments showed a significantly increase in affinity between chitosan and PGM at pH 5.2 compared to pH 6.3 and that the interactions were entropy driven. The TDM showed a significantly increase in strength of adhesion between chitosan discs and an artificial mucosal surface at pH 5.2 compared to pH 6.8, addition of PGM increased the total work of adhesion by a factor of 10 as compared to the wetted surface without PGM. These findings suggest that chitosan and PGM are able to interact by electrostatic interactions and by improving the conditions for electrostatic interactions, the adhesion between chitosan and PGM becomes stronger. Also, the three complementary methods were utilized to conclude the pH dependency on mucoadhesiveness. PMID:24291123

Meng-Lund, Emil; Muff-Westergaard, Christian; Sander, Camilla; Madelung, Peter; Jacobsen, Jette

2014-01-30

318

Composite magnetic chitosan microspheres: In situ preparation and characterization  

Microsoft Academic Search

A method for preparing magnetic crosslinked chitosan microparticles was developed. The chitosan (CS) encapsulated magnetic\\u000a particles were produced in alkaline conditions by in situ oxidation of the ferrous ions initially dispersed uniformly within\\u000a the polysaccharide matrix. The polymer was then crosslinked using glutaraldehyde (GLA). The products were characterized regarding\\u000a their size distribution and surface charge (by laser diffraction analysis, ?-potential

Doina Hritcu; Gianina Dodi; Mihaela Silion; Niculina Popa; Marcel I. Popa

2011-01-01

319

Osteogenesis promoted by calcium phosphate N, N-dicarboxymethyl chitosan  

Microsoft Academic Search

The effects of N,N-dicarboxymethyl chitosan (DCMC) on the precipitation of insoluble calcium salts, namely phosphate, sulfate, oxalate, carbonate, bicarbonate and fluoride, and magnesium salts, namely phosphate and carbonate, were studied. Results indicated that the chelating ability of DCMC interfered effectively with the well-known physico-chemical behaviour of magnesium and calcium salts. Dicarboxymethyl chitosan formed self-sustaining gels upon mixing with calcium acetate,

Riccardo A. A Muzzarelli; Viviana Ramos; Vesna Stanic; Bruno Dubini; Monica Mattioli-Belmonte; Giorgio Tosi; Roberto Giardino

1998-01-01

320

Wheat Germ Lectin Sorption by Chitosan Polyelectrolyte Complexes  

Microsoft Academic Search

The possible application of polyelectrolyte complexes (PEC) of chitosan and copolymers of maleic acid with N-vinylpyrrolidone, styrene, and ethylene and\\/or cross-linked chitin sorbents (CLCS) synthesized on the basis of PEC for sorption of wheat germ lectin (WGL) was studied. The synthesis of spherically granulated sorbents was shown. Compared to unmodified chitosan, there was a significant increase in sorption capacity of

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

2002-01-01

321

Release of rifampicin from chitosan, PLGA and chitosan-coated PLGA microparticles  

Microsoft Academic Search

Recently three groups of rifampicin (RIF)-loaded microparticles (MPs), consisting of chitosan (CHT), PLGA and PLGA\\/CHT mixtures, were assessed in terms of RIF-loading and retention during nebulisation. The CHT-coated PLGA MPs were found to exhibit high RIF-loading ability together with nebulisation ability, stability, and mucoadhesive properties. All MP types had comparable toxicity towards alveolar cells which was significantly lower than that

Maria Letizia Manca; Giuseppe Loy; Marco Zaru; Anna Maria Fadda; Sophia G. Antimisiaris

2008-01-01

322

PLGA, chitosan or chitosan-coated PLGA microparticles for alveolar delivery?  

Microsoft Academic Search

Various types of rifampicin (RIF)-loaded microparticles were compared for their stability during nebulization. Poly(lactide-co-glycolide) (PLGA), chitosan (CHT) and PLGA\\/CHT microparticles (MPs) were prepared by emulsion or precipitation techniques. MPs ability to be nebulized (NE%) as well as stability during freeze-drying or\\/and nebulization (NEED%), were evaluated after RIF extraction from MPs and determination by light spectroscopy. MP mean diameters and ?-potential

Maria-Letizia Manca; Spyridon Mourtas; Vassileios Dracopoulos; Anna Maria Fadda; Sophia G. Antimisiaris

2008-01-01

323

Chitosan and chitosan-co-poly(epsilon-caprolactone) grafted multiwalled carbon nanotube transducers for vapor sensing.  

PubMed

Vapor sensitive transducer films consisting of chitosan grafted (CNT-CS) and chitosan-co-polycaprolactone grafted (CNT-CS-PCL) multiwalled carbon nanotubes were prepared using a spray layer-by-layer technique. The synthesized materials (CNT-CS and CNT-CS-PCL) were characterized by Fourier transform infrared spectroscopy, 13C CP/MAS solid state nuclear magnetic resonance spectroscopy and thermogravimetric analysis. Both CNT-CS and CNT-CS-PCL transducers were analyzed for the response of volatile organic compounds and toluene vapors. The ranking of the relative resistance (A(r)) for both chitosan based transducers were as follows: toluene < chloroform < ethanol < methanol. The CNT transducer (CNT-CS) was correlated selectively with an exponential law to the inverse of Flory-Huggins interaction parameters, chi12. Dosing the films on the interdigitated electrodes with methanol, ethanol, chloroform and toluene vapors increased the film resistance of CNT-CS but decreased the resistance of CNT-CS-PCL compared to that of the reported transducers. PMID:24745242

Rana, Vijay Kumar; Akhtar, Shamim; Chatterjee, Sudipta; Mishra, Satyendra; Singh, Raj Pal; Ha, Chang-Sik

2014-03-01

324

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

325

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

326

Chitosan Composites for Bone Tissue Engineering--An Overview  

PubMed Central

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

Venkatesan, Jayachandran; Kim, Se-Kwon

2010-01-01

327

Physicochemical and functional characteristics of radiation-processed shrimp chitosan  

NASA Astrophysics Data System (ADS)

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

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

2011-07-01

328

Synthesis, characterization and antibacterial activity of new fluorescent chitosan derivatives.  

PubMed

The present work aims to the development of innovative new derivatives of chitosan that can be used for medical applications. This innovation is based on the synthesis and characterization of chitosan-g-aminoanthracene derivatives. Thus, N-(anthracen-9-yl)-4,6-dichloro-[1,3,5]-triazin-2-amine (AT) reacted with chitosan by the following steps: at first, cyanuric chloride reacted with 9-aminoanthracene to obtain N-(anthracen-9-yl)-4,6-dichloro-[1,3,5]-triazin-2-amine (AT), then the AT reacted with chitosan to obtain (CH-g-AT). The final product of CH-g-AT was separated, purified and re-crystallized by dioxane. The structure of the prepared chitosan derivatives was confirmed by FTIR-ATR, solid-NMR, TGA, X-RD, and DSC. The new chitosan derivatives showed fluorescence spectra in liquid and in solid state as well. CH-g-AT showed also high antibacterial activity against gram -ve species (Escherichia coli). PMID:24472505

P?ichystalová, Hana; Almonasy, Numan; Abdel-Mohsen, A M; Abdel-Rahman, Rasha M; Fouda, Moustafa M G; Vojtova, L; Kobera, Libor; Spotz, Zdenek; Burgert, Ladislav; Jancar, J

2014-04-01

329

Immobilization of naringin onto chitosan substrates by using ozone activation.  

PubMed

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

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

2014-03-01

330

THE USE OF CHITOSAN TO DAMAGE CRYPTOCOCCUS NEOFORMANS BIOFILMS  

PubMed Central

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

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

2009-01-01

331

Complex coacervation of soybean protein isolate and chitosan.  

PubMed

The formation of coacervates between soybean protein isolate (SPI) and chitosan was investigated by turbidimetric analysis and coacervate yield determination as a function of pH, temperature, time, ionic strength, total biopolymer concentration (TB(conc)) and protein to polysaccharide ratio (R(SPI/Chitosan)). The interaction between SPI and chitosan yielded a sponge-like coacervate phase and the optimum conditions for their coacervation were pH 6.0-6.5, a temperature of 25 °C, and a R(SPI/Chitosan) ratio of four independently of TB(conc). NaCl inhibited the complexation between the two biopolymers. Fourier transform infrared spectroscopy (FTIR) revealed that the coacervates were formed through the electrostatic interaction between the carboxyl groups of SPI (-COO(-)) and the amine groups of chitosan (-NH(3)(+)), however hydrogen bonding was also involved in the coacervation. Differential scanning calorimetry (DSC) thermograms indicated raised denaturation temperature and network thermal stability of SPI in the coacervates due to SPI-chitosan interactions. Scanning electron microscopy (SEM) micrographs revealed that the coacervates had a porous network structure interspaced by heterogeneously sized vacuoles. PMID:22868125

Huang, Guo-Qing; Sun, Yan-Ting; Xiao, Jun-Xia; Yang, Jian

2012-11-15

332

Chitosan-thioglycolic acid as a versatile antimicrobial agent.  

PubMed

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

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

2013-04-01

333

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.

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

2014-01-01

334

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

335

Chitosan blended bacterial cellulose as a smart material for biomedical application  

NASA Astrophysics Data System (ADS)

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

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

2009-03-01

336

Evaluation of fungal chitosan as a biocontrol and antibacterial agent using fluorescence-labeling.  

PubMed

Chitosan is a precious biological polysaccharide that could be applied in several fields. Fluorescein isothiocyanate-labeled chitosan (FITC-CTS) was synthesized as a macromolecular fluorophore added to fungal chitosan from Aspergillus niger, to investigate the interaction mechanism and antibacterial performance of (FITC-CTS) against Escherichia coli and Micrococcus leteus. Fluorescence imaging was used to demonstrate chitosan effect on the bacterial cells. Fluorescence density of treated bacteria with FITC-CTS was correlated with viable cell number. Electron micrographs of treated E. coli with fungal chitosan revealed that chitosan principally interact with bacterial cell wall, causing cell wall lyses with exposure time prolongation. Fungal chitosan could be proposed for bacterial growth control as a powerful, natural and safe alternative to synthetic and chemical bactericides. Fluorescence labeling proved to be an efficient tool for determining the antimicrobial activity of chitosan. PMID:23270832

Moussa, Shaaban H; Tayel, Ahmed A; Al-Turki, Ahmad I

2013-03-01

337

Antibacterial characteristics and activity of water-soluble chitosan derivatives prepared by the Maillard reaction.  

PubMed

The antibacterial activity of water-soluble chitosan derivatives prepared by Maillard reactions against Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Escherichia coli, Shigella dysenteriae, and Salmonella typhimurium was examined. Relatively high antibacterial activity against various microorganisms was noted for the chitosan-glucosamine derivative as compared to the acid-soluble chitosan. In addition, it was found that the susceptibility of the test organisms to the water-soluble chitosan derivative was higher in deionized water than in saline solution. Metal ions were also found to reduce the antibacterial activity of the water-soluble chitosan derivative on S. aureus. The marked increase in glucose level, protein content and lactate dehydrogenase (LDH) activity was observed in the cell supernatant of S. aureus exposed to the water-soluble chitosan derivative in deionized water. The results suggest that the water-soluble chitosan produced by Maillard reaction may be a promising commercial substitute for acid-soluble chitosan. PMID:21989311

Chung, Ying-Chien; Yeh, Jan-Ying; Tsai, Cheng-Fang

2011-01-01

338

The behaviors of Microcystis aeruginosa cells and extracellular microcystins during chitosan flocculation and flocs storage processes.  

PubMed

This work aimed to study the effects of chitosan on cell integrity and extracellular microcystins (MCs) of Microcystis aeruginosa cells during flocculation and flocs storage processes. The impacts of chitosan addition, flocculation stirring and flocs storage time were comprehensively detected to prevent or reduce cell lysis and MCs release. Response surface method (RSM) was applied to optimize the chitosan flocculation. Under chitosan concentration 7.31 mg/L and optimized mechanical conditions, 99% of M. aeruginosa cells were integrated removed. Furthermore, amounts of extracellular MCs were adsorbed by chitosan polymers in this process. With chitosan flocs protect, though cells showed some damage, extracellular MCs concentration in flocculated samples lower than background level within first 2 d. However, lots of MCs release was observed after 4d which may result from chitosan degradation and cells lysis. Therefore, chitosan flocs should be treated within 2d to prevent the adsorbed MCs releasing again. PMID:24262841

Pei, Hai-Yan; Ma, Chun-Xia; Hu, Wen-Rong; Sun, Feng

2014-01-01

339

Enhancement of bronchial octreotide absorption by chitosan and N-trimethyl chitosan shows linear in vitro\\/in vivo correlation  

Microsoft Academic Search

Chitosan is a biocompatible polysaccharide of natural origin that can act as a permeation enhancer. In this study, we used an integral in vitro\\/in vivo correlation approach to: a) investigate polysaccharide-mediated absorption kinetics of the peptide drug octreotide across mammalian airway epithelium, b) assess formulation toxicity, c) correlate the mechanism of permeation enhancement. The 20% and 60% N-trimethylated chitosan derivatives

Bogdan I. Florea; Maya Thanou; Hans E. Junginger; Gerrit Borchard

2006-01-01

340

Dynamic surface tension and dilational viscoelasticity of adsorption layers of alkylated chitosans and surfactant–chitosan complexes  

Microsoft Academic Search

The kinetics of the adsorption at the air-water interface and the processes of the structure formation inside the adsorption layers of hydrophobically modified systems [alkylated chitosans and sodium dodecyl sulfate (SDS)–chitosan (Ch) complexes] have been studied by the tensiometric method based on the axisymmetric rising-bubble-shape analysis as a function of the bulk concentration of polymers and the ageing time of

Valery G. Babak; Jacques Desbrieres

2006-01-01

341

Tannic acid incorporation in chitosan-based microparticles and in vitro controlled release  

Microsoft Academic Search

Chitosan, a natural polycationic polysaccharide, was coupled with two polyanionic polymers: Na-alginate and carboxymethylcellulose\\u000a (CMC) and with tannic acid (TA) obtaining three species of self-assembled complexes: chitosan\\/alginate\\/TA (sample 1), chitosan\\/TA\\u000a (sample 2) and chitosan\\/CMC\\/TA (sample 3). The microparticle formation was achieved by dropwise addition of one solution into\\u000a other by using a coaxial airflow sprayer. These systems were characterized with

Neculai Aelenei; Marcel Ionel Popa; Ovidiu Novac; Gabriela Lisa; Lacramioara Balaita

2009-01-01

342

Chitosan microparticles containing plasmid DNA as potential oral gene delivery system  

Microsoft Academic Search

The potential of chitosan as a polycationic gene carrier for oral administration has been explored since 1990s. Chitosan has been shown to effectively bind DNA in saline or acetic acid solution and protect DNA from nuclease degradation. In this study, pDNA (plasmid DNA) was encapsulated in chitosan microparticles. Chitosan–DNA microparticles were prepared using a complex coacervation process and stability of

Ülker Guliyeva; Filiz Öner; ?ule Özsoy; R?fk? Haziro?lu

2006-01-01

343

In Situ Formation of Silver Nanoparticles within Chitosan-attached Cotton Fabric for Antibacterial Property  

Microsoft Academic Search

This work involves chemical modification of cotton fabrics by natural, biocompatible, and biodegradable polysaccharide — chitosan — followed by incorporating silver nanoparticles in the fabrics. The excellent chelating property of chitosan binds the silver metal ions that are later on reduced to nanoparticles giving rise to chitosan-attached nanosilver-loaded fabrics. The silver nanoparticles-loaded chitosan-attached fabric has been characterized by surface plasmon

Varsha Thomas; M. Bajpai; S. K. Bajpai

2011-01-01

344

Study on CM-chitosan\\/activated carbon hybrid gel films formed with EB irradiation  

Microsoft Academic Search

A series of novel hybrid gel films were prepared from carboxymethylated chitosan (CM-chitosan) and activated carbon (AC) by irradiation of compression-molded CM-chitosan\\/AC mixture in physical gel state with electron beam (EB) at room temperature. The formation, properties and structure of CM-chitosan\\/AC hybrid gel films were discussed in terms of gel fraction, swelling, mechanical property, SEM image and XPS spectra. Compared

Long Zhao; Fang Luo; Maolin Zhai; Hiroshi Mitomo; Fumio Yoshii

2008-01-01

345

Preparation and anticoagulant activity of a low-molecular-weight sulfated chitosan  

Microsoft Academic Search

Synthesis of chitosan sulfates with low molecular weight (Mv 9000–35,000Da) was carried out by sulfation of low molecular weight chitosan (Mv 10,000–50,000Da). The oleum was used as sulfating agent and dimethylfornamide as medium. The chitosans were prepared by enzymatic and acidic hydrolysis of initial high molecular weight chitosan as well as by extrusion solid-state deacetylation of chitin. As was shown

G. Vikhoreva; G. Bannikova; P. Stolbushkina; A. Panov; N. Drozd; V. Makarov; V. Varlamov; L. Gal'braikh

2005-01-01

346

Fabrication of chitosan\\/poly(?-caprolactone) composite hydrogels for tissue engineering applications  

Microsoft Academic Search

The aim of this study was to fabricate three-dimensional (3D) porous chitosan\\/poly(?-caprolactone) (PCL) hydrogels with improved\\u000a mechanical properties for tissue engineering applications. A modified emulsion lyophilisation technique was developed to produce\\u000a 3D chitosan\\/PCL hydrogels. The addition of 25 and 50 wt% of PCL into chitosan substantially enhanced the compressive strength\\u000a of composite hydrogel 160 and 290%, respectively, compared to pure chitosan

Xia Zhong; Chengdong Ji; Andrew K. L. Chan; Sergei G. Kazarian; Andrew Ruys; Fariba Dehghani

2011-01-01

347

Comparison of Acid-Soluble and Water-Soluble Chitosan as Coagulants in Removing Bentonite Suspensions  

Microsoft Academic Search

Chitosan is a biodegradable cationic polymer that may be a potential substitute for aluminum salts in water treatment systems.\\u000a In our study, we compared the coagulation performances of chitosan with those of coagulant mixtures of chitosan and aluminum\\u000a sulfate and chitosan and poly-aluminum chloride, respectively. The coagulation efficiency was evaluated in terms of coagulant\\u000a dosage, solution pH, settling velocity of

Chih-Yu Chen; Ying-Chien Chung

2011-01-01

348

Toxicity and gut associated lymphoid tissue translocation of polymyxin B orally administered by alginate/chitosan microparticles in rats.  

PubMed

Fluorescent calcium alginate/chitosan microparticles, prepared using a spray-drying technique followed by crosslinking reactions with calcium ions and chitosan, were assayed in-vivo for polymyxin B (PMB) oral toxicity, uptake by Peyer's patches and PMB oral absorption. A single PMB dose (300 mg kg(-1)), loaded in microparticles or dissolved in water, was administered to rats by oral gavage under fasted and fed conditions. By monitoring incidence of mortality, animal behaviour, clinical signs and abnormality in several organs, PMB in water solution was found lethal at a dose lower than the LD50 (790 mg kg(-1)) in the fasted state and toxic for the gastrointestinal tract in the fed state. However, no signs of acute toxicity at the level of the gastrointestinal tract were observed when animals were administered PMB loaded in microparticles under fasted and fed conditions. A lower PMB dose (125 mg kg(-1)), loaded in microparticles or dissolved in water, was given to rats in a fed state to determine PMB levels in Peyer's patches, urine and serum as well as to detect the loaded microparticles inside Peyer's patches for three days after dosing. Abnormalities were observed at gut level only when PMB was dosed in a water solution. Detectable antibiotic levels in Peyer's patches and urine as well as more constant PMB serum concentrations were provided by dosing PMB loaded in microparticles. Therefore, the use of alginate/chitosan microparticles to target the lymphatic system could improve safety when administering PMB orally. PMID:18088501

Coppi, Gilberto; Bondi, Moreno; Coppi, Andrea; Rossi, Tiziana; Sergi, Santo; Iannuccelli, Valentina

2008-01-01

349

Preparation of zolmitriptan–chitosan microparticles by spray drying for nasal delivery  

Microsoft Academic Search

The objective of this study was to use spray drying to prepare mucoadhesive dry powders of the antimigraine drug, zolmitriptan, in combination with the natural polymer, chitosan, for nasal administration. The effect of type, molecular weight, and proportion of chitosan on the powder and particle characteristics was also studied. Solutions containing different proportions of chitosans were prepared and spray dried.

Amjad Alhalaweh; Staffan Andersson; Sitaram P. Velaga

2009-01-01

350

Improved barrier and mechanical properties of novel hydroxypropyl methylcellulose edible films with chitosan\\/tripolyphosphate nanoparticles  

Microsoft Academic Search

Chitosan\\/tripolyphosphate nanoparticles were prepared and incorporated in hydroxypropyl methylcellulose (HPMC) films. FT-IR and transmission electron microscopy (TEM) analyses of the nanoparticles, mechanical properties, water vapor permeability, thermal stability, scanning electron microscopy (SEM) of the films were analyzed. Incorporation of chitosan nanoparticles in the films improved their mechanical and film barrier properties significantly. The chitosan nanoparticles tend to occupy the empty

Márcia R. de Moura; Fauze A. Aouada; Roberto J. Avena-Bustillos; Tara H. McHugh; John M. Krochta; Luiz H. C. Mattoso

2009-01-01

351

Synthesis and characterization of biodegradable TPP\\/genipin co-crosslinked chitosan gel beads  

Microsoft Academic Search

Novel chitosan gel beads were synthesized by a coupled ionic and chemical co-crosslinking mechanism. Tripolyphosphate (TPP) and a naturally occurring crosslinking reagent, genipin, which has been used in herbal medicine, were employed, respectively, as an ionic and a chemical crosslinkers to prepare the chitosan-based networks of gel beads. The competitive crosslinking of chitosan with ionic crosslinker (TPP) and chemical crosslinker

Fwu-Long Mi; Hsing-Wen Sung; Shin-Shing Shyu; Chia-Ching Su; Chih-Kang Peng

2003-01-01

352

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

353

Nano and micro mechanical properties of uncross-linked and cross-linked chitosan films.  

PubMed

The aim of this study is to determine the nano and micro mechanical properties for uncross-linked and cross-linked chitosan films. Specifically, we looked at nanoindentation hardness, microhardness, and elastic modulus. It is important to study the nano and microscale mechanical properties of chitosan since chitosan has been widely used for biomedical applications. Using the solvent-cast method, the chitosan films were prepared at room temperature on the cleaned glass plates. The chitosan solution was prepared by dissolving chitosan in acetic acid 1% (v/v). Tripolyphosphate (TPP) was used to create the cross-links between amine groups in chitosan and phosphate groups in TPP. In this study, atomic force microscopy was used to measure the nanoindentation hardness and surface topography of the uncross-linked and cross-linked chitosan films. Elastic modulus was then calculated from the nanoindentation results. The effective elastic modulus was determined by microhardness with some modifications to previous theories. The microhardness of the chitosan films were measured using Vicker's hardness meter under three different loads. Our results show that the microhardness and elastic modulus for cross-linked chitosan films are higher than the uncross-linked films. However, the cross-linked chitosan films show increased brittleness when compared to uncross-linked films. By increasing the load magnitude, the microhardness increases for both uncross-linked and cross-linked chitosan films. PMID:22100082

Aryaei, Ashkan; Jayatissa, Ahalapitiya H; Jayasuriya, A Champa

2012-01-01

354

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

Microsoft Academic Search

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

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

2009-01-01

355

Using Chitosan for Improving the Dyeability of Cotton Fabrics with Mangosteen Rind Dye  

Microsoft Academic Search

The study examined the influence of chitosan to improve dye absorption on cotton farbric using Mangosteen Rind. The results of this study concluded that the cotton fabrics treated with chitosan had better depth of shade than those of the untreated fabrics dyed with Mangosteen Rind. This may be because the chitosan treated cotton fabrics provided more dye sites than those

Siriwan Kittinaovarat

356

Synthesis, Structure and Properties of Novel Quaternized Carboxymethyl Chitosan with Drug Loading Capacity  

Microsoft Academic Search

A modified approach to prepare novel amphipathic octadecyl-quaternized carboxymethyl chitosan (QACMC) was reported, in which carboxymethyl chitosan (CMC), prepared from chitosan, was made to react with glycidyl octadecyl dimethylammonium chloride; thus, the octadecyl quaternary ammonium group was introduced into CMC. The structure and thermal properties of these derivatives were characterized by Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance

Xiaofei Liang; Hanjie Wang; Hui Tian; Hao Luo; Jin Chang

2008-01-01

357

Polyaniline–chitosan nanocomposite: High performance hydrogen sensor from new principle  

Microsoft Academic Search

A high selectivity and response towards hydrogen gas is realized with a composite of polyaniline nanofibers embedded in chitosan matrix. The enhanced response originated from the new sensing mechanism related with the composite nature of chitosan and polyaniline. Based on the high gas sensing performance through nanostructured resistive polyaniline nanofibers, the swelling of chitosan as the matrix distributing among the

Wei Li; Dong Mi Jang; Sea Yong An; Dojin Kim; Soon-Ku Hong; Hyojin Kim

358

Electrochemically deposited chitosan hydrogel for horseradish peroxidase immobilization through gold nanoparticles self-assembly  

Microsoft Academic Search

A new strategy for immobilization of horseradish peroxidase (HRP) has been presented by self-assembling gold nanoparticles on chitosan hydrogel modified Au electrode. From a mildly acidic chitosan solution, a chitosan film is electrochemically deposited on Au electrode surface via a negative voltage bias. This process is accompanied by the hydrogen evolution reaction, and the released hydrogen gas made the deposited

Xi-Liang Luo; Jing-Juan Xu; Qing Zhang; Gong-Jun Yang; Hong-Yuan Chen

2005-01-01

359

Effect of surface roughness of chitosan-based microspheres on cell adhesion  

Microsoft Academic Search

Microspheres are novel candidate materials for microcarriers and tissue-engineering scaffolds. Chitosan microspheres were selected as the base materials because of their excellent properties for biomedical applications. But their smooth surfaces were not adapted for cell attachment. Hence, in order to improve the roughness of chitosan microspheres, ?-TCP\\/chitosan composite microspheres were developed. From SEM photographs, the coarse surfaces of composite microspheres

Qingfeng Zan; Chen Wang; Limin Dong; Peng Cheng; Jiemo Tian

2008-01-01

360

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

PubMed Central

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

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

2013-01-01

361

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

Microsoft Academic Search

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

Hui-Chia Yang; Min-Hsiung Hon

2010-01-01

362

Characterization and evaluation of hydrophobically modified chitosan scaffolds: Towards design of enzyme immobilized flow-through electrodes  

Microsoft Academic Search

Chitosan scaffolds were fabricated by application of thermally induced phase separation from aqueous solutions of unmodified chitosan and hydrophobically modified chitosan polymer. The final pore structure, in terms of diameter and geometry, were correlated to freezing temperature and freezing time for both the unmodified and hydrophobically modified chitosan polymer. Results showed that the resulting pore structure is strongly dependent upon

Michael J. Cooney; Jana Petermann; Carolin Lau; Shelley D. Minteer

2009-01-01

363

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.

2012-01-01

364

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

365

Towards better modeling of chitosan nanoparticles production: screening different factors and comparing two experimental designs.  

PubMed

The aim of this study is to utilize statistical designs and mathematical modeling to end the continuous debate about the different variables that influence the production of nanoparticles using the ionic gelation method between the biopolymer chitosan (CS) and tripolyphosphate (TPP) ion. Preliminary experiments were adopted to extract the optimum conditions for the nanoparticles preparation and model construction. Critical process parameters were screened using the one-factor-at-a-time (OFAT) approach to select optimum experimental regions. Finally, these factors were optimized using two different methods of response surface modeling; the Box-Behnken and the D-optimal. The significant models showed excellent fitting of the data. The two methods were validated using a set of check points and were subsequently compared. Good agreement between actual and predicted values was obtained though the D-optimal model was more successful in predicting the particle size of the prepared nanoparticles with percentage bias as small as 1.49%. Nanoparticles were produced with diameters ranging from 52.21 nm to 400.30 nm, particle polydispersity from 0.06 to 0.40 and suitable morphology. This work provides an overview on the production of chitosan nanoparticles with desirable size enabling their successful use in drugs delivery and targeting or in any nanotechnology or interfacial application. PMID:24355618

Abdel-Hafez, Salma M; Hathout, Rania M; Sammour, Omaima A

2014-03-01

366

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.

Liu, Karen C.; Yeo, Yoon

2013-01-01

367

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

368

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

Microsoft Academic Search

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

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

2007-01-01

369

Radiation synthesis of chitosan stabilized gold nanoparticles comparison between e- beam and ? irradiation  

NASA Astrophysics Data System (ADS)

Gold nanoparticles were synthesized via radiolytic reduction of Au(III) salts induced by e- beam or ?-irradiation, using chitosan as a stabilizer. The effect of irradiation dose, chitosan concentration and the conditioning of HAuCl4-chitosan solutions were studied. UV-visible absorption measurements reveal that the size of Au clusters formed immediately after irradiation is correlated with the extent of chitosan scission chain of chitosan and fall with the increase of dose absorbed. This effect is more pronounced with solution conditioned under Argon (Ar). Au clusters coalesce to form stable nanoparticles after two weeks.

Vo, Khoa Dang Nguyen; Kowandy, Christelle; Dupont, Laurent; Coqueret, Xavier; Hien, Nguyen Quoc

2014-01-01

370

Response surface methodology in the optimization of tea polyphenols-loaded chitosan nanoclusters formulations  

Microsoft Academic Search

Response surface methodology was used to optimize tea polyphenols-loaded chitosan nanoclusters preparation conditions, including\\u000a carboxymethyl chitosan concentration, chitosan hydrochloride concentration and amount of tea polyphenols. The responses particle\\u000a size and entrapment efficiency of nanoclusters were studied. The optimum conditions of carboxymethyl chitosan concentration,\\u000a chitosan hydrochloride concentration and amount of tea polyphenols were found to be 3.63, 1.19 and 10.94 mg\\/mL, respectively.

Jin Liang; Feng Li; Yong Fang; Wenjian Yang; Xinxin An; Liyan Zhao; Zhihong Xin; Qiuhui Hu

2010-01-01

371

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

372

[The possibilities of using a chitin and chitosan in wounds treatment].  

PubMed

Chitin and chitosan are natural polysaccharides. In this study, we presented the possibilities of using chitin and chitosan in medical practice and experimental studies. Chitin and chitosan, based wound dressings available as commercial products, were presented. The directions of future progress in employment chitin and chitosan in treatment of many kinds of wounds were also described. In this study, the main properties of these polymers were established. The usefulness of the chitin and chitosan as hemostatic products, wound dressing and skin substitutes was emphasized. PMID:24596043

Mazurek, Piotr; Kuli?ski, Sebastian; Gosk, Jerzy

2013-01-01

373

Preparation and characterization of chitosan hybrid membranes containing polyethylacrylate and polybutylacrylate.  

PubMed

Chitosan hybrid membranes were prepared in the presence of polyethylacrylate and polybutylacrylate and characterized by measuring stress, strain, Young's modulus, swelling behavior and antibacterial properties against gram-negative and gram-positive bacteria using IR spectroscopy and scanning electron microscopy (SEM). The results show that the mechanical properties of the hybrid membranes were enhanced using polybutylacrylate. SEM images showed homogeneity of the prepared membranes. The swelling degree was of the order chitosan > chitosan/polyethylacrylate > chitosan/polybutylacrylate. Antibacterial properties of the hybrid membranes with polybutylacrylate and polyethylacrylate were higher than those of chitosan membranes without any additives. PMID:22068566

Abdel-Mohdy, F A; El-Sawy, S M; Abou-Okeil, A

2011-12-01

374

Amphiphilic N-[2(3)-(dodec-2?-en-1?-yl)succinoyl]chitosan: Synthesis and properties  

Microsoft Academic Search

Amphiphilic N-[2(3)-(dodec-2?-en-1?-yl)succinoyl]chitosan (DDC-chitosan) of varying degree of substitution was synthesized by the reaction of chitosan with (2-dodecen-1-yl)succinic anhydride in 1% acetic acid\\/methanol (1:1 v\\/v) solution. A degree of substitution (5–30mol.%) depended on anhydride\\/amino group ratio. Surface tension activity, rheological and foam-forming properties of DDC-chitosan were strongly determined by the degree of substitution. Viscosity experiments revealed inter\\/intramolecular interactions of DDC-chitosan macromolecules

V. E. Tikhonov; E. A. Stepnova; V. G. Babak; M. A. Krayukhina; B. B. Berezin; I. A. Yamskov

2008-01-01

375

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

376

Use of chitosan scaffolds for repairing rat sciatic nerve defects.  

PubMed

Neurotmesis must be surgically treated by direct end-to-end suture of the two nerve stumps or by a nerve graft harvested from elsewhere in the body in case of tissue loss. To avoid secondary damage due to harvesting of the nerve graft, a tube-guide can be used to bridge the nerve gap. Previously, our group developed and tested hybrid chitosan membranes for peripheral nerve tubulization and showed that freeze-dried chitosan type III membranes were particularly effective for improving peripheral nerve functional recovery after axonotmesis. Chitosan type III membranes have about 110 microm pores and about 90% of porosity, due to the employment of freeze-drying technique. The present study aimed to verify if chitosan type III membranes can be successfully used also for improving peripheral nerve functional recovery after neurotmesis of the rat sciatic nerve. Sasco Sprague-Dawley adult rats were divided into 6 groups: Group 1: end-to-end neurorrhaphy enwrapped by chitosan membrane type III (End-to-EndChitll); Group 2: 10mm-nerve gap bridged by an autologous nerve graft enwrapped by chitosan membrane type III (Graf180degreeChitIII); Group 3: 10 mm-nerve gap bridged by chitosan type III tube-guides (GapChitIII); These 3 experimental groups were compared with 3 control groups, respectively: Group 4: 10 mm-nerve gap bridged by an autologous nerve graft (Graft180degree); Group 5: 10 mm-nerve gap bridged by PLGA 90:10 tube-guides (PLGA); Group 6: end-to-end neurorrhaphy alone (End-to-End). Motor and sensory functional recovery were evaluated throughout a healing period of 20 weeks using extensor postural thrust (EPT), withdrawal reflex latency (WRL) and ankle kinematics. Regenerated nerves withdrawn at the end of the experiment were analysed histologically. Results showed that nerve regeneration was successful in all experimental and control groups and that chitosan type III tubulization induced a significantly better nerve regeneration and functional recovery in comparison to PLGA tubulization control. Further investigation is needed to explore the mechanisms at the basis of the positive effects of chitosan type III on axonal regeneration. PMID:21287974

Simões, Maria J; Amado, Sandra; Gärtner, Andrea; Armada-Da-Silva, Paulo A S; Raimondo, Stefania; Vieira, Marcia; Luís, Ana L; Shirosaki, Yuki; Veloso, António P; Santos, José D; Varejão, Artur S P; Geuna, Stefano; Maurício, Ana C

2010-01-01

377

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

378

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 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

379

Fabrication, characterization and bioevaluation of silibinin loaded chitosan nanoparticles.  

PubMed

Silibinin is reported to possess multiple biological activities. However, its hydrophobic nature limits its bioavailability compromising in vivo biological activities. Nanoparticles-based delivery of such molecules has emerged as new technique to resolve these issues. Bio-degradable, compatible and adhesive nature of chitosan has recently attracted its suitability as a carrier for biologically active molecules. This study presents fabrication and characterization of chitosan-tripolyphosphate based encapsulation of silibinin. Various preparations of silibinin encapsulated chitosan-tripolyphosphate nanoparticles were studied for particle size, morphology, zeta-potential, and encapsulation efficiencies. Preparations were also evaluated for cytotoxic activities in vitro. The optimized silibinin loaded chitosan nanoparticles were of 263.7±4.1nm in particle size with zeta potential 37.4±1.57mV. Nanoparticles showed high silibinin encapsulation efficiencies (82.94±1.82%). No chemical interactions between silibinin and chitosan were observed in FTIR analysis. Powder X-ray diffraction analysis revealed transformed physical state of silibinin after encapsulation. Surface morphology and thermal behaviour were determined using TEM and DSC analysis. Encapsulated silibinin displayed increased dissolution and better cytotoxicity against human prostate cancer cells (DU145) than silibinin alone. PMID:24863917

Pooja, Deep; Babu Bikkina, Dileep J; Kulhari, Hitesh; Nikhila, Nalla; Chinde, Srinivas; Raghavendra, Y M; Sreedhar, B; Tiwari, Ashok K

2014-08-01

380

Preparation of chitosan-TPP microspheres as resveratrol carriers.  

PubMed

Resveratrol (3,4',5-trihydroxy-trans-stilbene)-loaded chitosan-sodium tripolyphosphate (TPP) microspheres using high (310 to 375 kDa) and medium (190 to 310 kDa) molecular weight chitosan and TPP in varying concentrations were produced to improve resveratrol bioavailability. A 450 ?m nozzle encapsulator was used to produce the microspheres. The mean microsphere particle size was between 160 and 206 ?m, and exhibited a narrower size distribution as the TPP solution concentration increased. The encapsulation efficiency increased from 94% to 99% with a decrease in chitosan concentration from 1% to 0.5% and a decrease in crystallinity of the microspheres. FTIR data showed a polyelectrolyte interaction between chitosan and TPP. X-ray diffraction patterns were matched up with DSC and FTIR, which shows decrease of crystallinity and enhancement of hydrogen bonding with TPP concentration. An increase in the concentration of TPP solution from 1% to 3% led to a lower initial burst of resveratrol release. These results suggest that chitosan-TPP microspheres could be used as a potential delivery system to control the release of resveratrol. PMID:24621001

Cho, Ah Ra; Chun, Yong Gi; Kim, Bum Keun; Park, Dong June

2014-04-01

381

Thiopyrazole preactivated chitosan: combining mucoadhesion and drug delivery.  

PubMed

The objective of this study was to develop a preactivated chitosan derivative by the introduction of thioglycolic acid followed by 3-methyl-1-phenylpyrazole-5-thiol (MPPT) coupling via disulfide bond formation. The newly synthesized conjugate was characterized in terms of water-absorbing capacity, cohesive properties, mucoadhesion and drug release kinetics. Further in vitro characterization was conducted regarding permeation enhancement of the model compound fluorescein isothiocyanate dextran (FD4) and cytotoxic effects on Caco-2 cells. Based on the attachment of the hydrophobic residue, chitosan-S-S-MPPT test discs showed increased stability of the polymer matrix as well as improved water uptake and liberation of fluorescein isothiocyanate dextran (FD4) compared to chitosan only. The mucoadhesive qualities on porcine intestinal mucosa could be improved 38-fold based on the enhanced bonding between chitosan-S-S-MPPT and mucus through the thiol/disulfide exchange reaction of polymer and mucosal cysteine-rich domains supported by MPPT as the leaving group. This novel biomaterial presents a disulfide conjugation-based delivery system that releases the antibacterial thiopyrazole when the polymer comes into contact with the intestinal mucosa. These properties, together with the safe toxicological profile, make chitosan-S-S-MPPT a valuable carrier for mucoadhesive drug delivery systems and a promising matrix for the development of antimicrobial excipients. PMID:23321304

Müller, Christiane; Ma, Benjamin N; Gust, Ronald; Bernkop-Schnürch, Andreas

2013-05-01

382

Chitosan-based nanocoatings for hypothermic storage of living cells.  

PubMed

The formation of ultrathin chitosan-based nanocoating on HL-60 model cells and their protective function in hypothermic storage are presented. HL-60 cells are encapsulated in ultrathin shells by adsorbing cationic and anionic chitosan derivatives in a stepwise, layer-by-layer, procedure carried out in an aqueous medium under mild conditions. The chitosan-based films are also deposited on model lipid bilayer and the interactions are studied using ellipsometry and atomic force microscopy. The cells covered with the chitosan-based films and stored at 4?°C for 24?h express viability comparable to that of the control sample incubated at 37?°C, while the unprotected cells stored under the same conditions do not show viability. It is shown that the chitosan-based shell protects HL-60 cells against damaging effect of hypothermic storage. Such nanocoatings provide protection, mechanical stability, and support the cell membrane, while ensuring penetration of small molecules such as nutrients/gases what is essential for cell viability. PMID:23966342

Bulwan, Maria; Antosiak-Iwa?ska, Magdalena; Godlewska, Ewa; Granicka, Ludomira; Zapotoczny, Szczepan; Nowakowska, Maria

2013-11-01

383

In vitro insulin release from thermosensitive chitosan hydrogel.  

PubMed

Recently, great attention has been paid to in situ gel-forming chitosan/glycerol-phosphate (chitosan/Gp) solution due to their good biodegradability and thermosensitivity. This in situ gel-forming system is injectable fluid that can be introduced into the body in a minimally invasive manner prior to solidifying within the desired tissue. At the present study, insulin release from chitosan/Gp solution has been investigated. Insulin in different concentrations was loaded in two formulations of chitosan/Gp solution and in vitro drug release was studied over a period of 3 weeks. Results indicated that the release of insulin from chitosan/Gp gel decreases by increasing in Gp salt and initial insulin concentration. Stability of released insulin was investigated by 8-anilino-1-naphthalenesulfonate probe. Results proved that insulin have been released in its native form. Because of simple preparation and administration, prolonged release of insulin and stability of released insulin, this in situ gel-forming system could be used as a controlled release delivery system for insulin. PMID:22391886

Khodaverdi, Elham; Tafaghodi, Mohsen; Ganji, Fariba; Abnoos, Khalil; Naghizadeh, Hanie

2012-06-01

384

Chitosan-glutaraldehyde copolymers and their sorption properties.  

PubMed

This study reports the preparation of chitosan-glutaraldehyde (Chi-Glu) copolymers at modified reaction conditions such as the temperature prior to gelation, pH, and reagent ratios. The chitosan copolymers were characterized using infrared spectroscopy (FT-IR), CHN elemental analysis, and thermal gravimetric analysis (TGA). Evidence of self-polymerized glutaraldehyde was supported by CHN and TGA results. The sorption properties of Chi-Glu copolymers were evaluated in aqueous solutions containing p-nitrophenol at variable pH (4.6, 6.6, and 9.0). The sorption properties of the copolymers correlated with the level of the accessibility of the sorption sites in accordance with the relative cross-linker content. The relative sorption capacity of the Chi-Glu copolymers increases as the level of cross-linking increases. Chitosan displays the lowest sorptive uptake while an optimal sorption capacity was concluded at the 4:1 glutaraldehyde:chitosan monomer mole ratio, in close agreement with the three reactive sites (i.e. OH/NH) per glucosamine monomer. The PNP dye probe was determined to bind to chitosan through an electrostatic interaction due to the increased sorption capacity of the phenolate anion, as evidenced by the change in pH from 4.6 to 9.0. PMID:24815406

Poon, Louis; Wilson, Lee D; Headley, John V

2014-08-30

385

Immobilization of Glucose Oxidase in Alginate-Chitosan Microcapsules  

PubMed Central

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

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

2011-01-01

386

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

387

Influence of abiotic factors on the antimicrobial activity of chitosan.  

PubMed

In an effort to bypass the adverse secondary effects attributed to the traditional therapeutic approaches used to treat skin disorders (such as atopic dermatitis), alternative antimicrobials have recently been suggested. One such antimicrobial is chitosan, owing to the already proved biological properties associated with its use. However, the influence of abiotic factors on such activities warrants evaluation. This research effort assessed the antimicrobial activity of chitosan upon skin microorganisms (Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli) in vitro when subject to a combination of different abiotic factors such as pH, ionic strength, organic acids and free fatty acids. Free fatty acids, ionic strength and pH significantly affected chitosan's capability of reducing the viable numbers of S. aureus. This antimicrobial action was potentiated in the presence of palmitic acid and a lower ionic strength (0.2% NaCl), while a higher ionic strength (0.4% NaCl) favored chitosan's action upon the reduction of viable numbers of S. epidermidis and E. coli. Although further studies are needed, these preliminary results advocate that chitosan can in the future be potentially considered as an antimicrobial of choice when handling symptoms associated with atopic dermatitis. PMID:24330167

Tavaria, Freni K; Costa, Eduardo M; Gens, Eduardo J; Malcata, Francisco Xavier; Pintado, Manuela E

2013-12-01

388

Therapeutic efficacies of chitosan against Pneumocystis pneumonia of immunosuppressed rat.  

PubMed

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

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

2014-07-01

389

Docetaxel loaded chitosan nanoparticles: Formulation, characterization and cytotoxicity studies.  

PubMed

The primary objective of the present investigation was to explore biodegradable chitosan as a polymeric material for formulating docetaxel nanoparticles (DTX-NPs) to be used as a delivery system for breast cancer treatment. Docetaxel loaded chitosan nanoparticles were formulated by water-in-oil nanoemulsion system and characterized in terms of particle size, zeta potential, polydispersity index, drug entrapment efficiency (EE), loading capacity (LC), scanning electron microscopy (SEM), in vitro release study and drug release kinetics. Further, to evaluate the potential anticancer efficacy of docetaxel loaded chitosan nanoparticulate system, in vitro cytotoxicity studies on human breast cancer cell line (MDA-MB-231) were carried out. The morphological studies revealed the spherical shape of docetaxel loaded chitosan nanoparticles having an average size of 170.1±5.42-227.6±7.87nm, polydispersity index in the range of 0.215±0.041-0.378±0.059 and zeta potential between 28.3 and 31.4mV. Nanoparticles exhibited 65-76% of drug entrapment and 8-12% loading capacity releasing about 68-83% of the drug within 12h following Higuchi's square-root kinetics. An increase of 20% MDA-MB-231 cell line growth inhibition was determined by docetaxel loaded chitosan nanoparticles with respect to the free drug after 72h incubation. PMID:24971551

Jain, Ankit; Thakur, Kanika; Kush, Preeti; Jain, Upendra K

2014-08-01

390

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

PubMed

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

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

2014-04-01

391

Degradation of chitosan by gamma ray with presence of hydrogen peroxide  

NASA Astrophysics Data System (ADS)

The radiation degraded chitosan samples were prepared by swelling the chitosan powder in water and exposed for gamma irradiation. The ratio chitosan to water was 1:6 with the presence of hydrogen peroxide (H2O2), 1%-5%. These chitosan-water mixtures were irradiated at 6kGy, which is the lowest irradiation dose that facility can offered. All samples were purified and proceed with characterization. The molecular weight (MW) study was monitored by size exclusion chromatography-multi angle laser light scattering (SEC-MALLS). Results showed that MW of chitosan reduced as the dose increased. Application of H2O2 enhanced the degradation rate of chitosan even at very low irradiation dose. Homogenous degradation also occurred during treatment with H2O2based on the polydispersity index (PDI) derived from the calculation of weight average molecular weight over number average molecular weight (Mw/Mn). Mechanism of chitosan radiation degradation with and without hydrogen peroxide was also discussed in this paper. Structure of degraded products was characterized with Fourier-transform infrared spectra. The degree of deacetylation (DDA) values of the samples was determined by acid-base titration. Solubility test results showed that, chitosan powder even at low Mw was insoluble in water even at low pH water. Chitosan as well as irradiated chitosan powder are soluble in strong and weak acid solution. Further discussion on behaviours of radiation degraded chitosan will be elaborated more in this paper.

Mahmud, Maznah; Naziri, Muhammad Ihsan; Yacob, Norzita; Talip, Norhashidah; Abdullah, Zahid

2014-02-01

392

Use of myocardial matrix in a chitosan-based full-thickness heart patch.  

PubMed

A novel cardiac scaffold comprised of decellularized porcine heart matrix was investigated for use as a biodegradable patch with a potential for surgical reconstruction of the right ventricular outflow tract. Powdered heart matrix solution was blended with chitosan and lyophilized to form three-dimensional scaffolds. For this investigation, we examined the influence of different blending ratios of heart matrix to chitosan on porosity and mechanical properties, then gene expression and electrophysiological function of invading neonatal rat ventricular myocytes (NRVM) compared to type-A gelatin/chitosan composite scaffolds. Heart matrix/chitosan-blended hydrogels (1.6?mg/mL heart matrix) had similar porosity (109±34??m), and elastic modulus (13.2±4.0?kPa) as previously published gelatin/chitosan scaffolds. Heart matrix/chitosan hydrogels maintained>80% viability and had higher NRVM retention (?1000 cells/mm(2)) than gelatin/chitosan scaffolds. There was a significant increase in ?-myosin heavy chain and connexin-43 expression in NRVM cultured on heart matrix/chitosan scaffolds after 14 days compared with gelatin/chitosan scaffolds. Further, heart matrix/chitosan scaffolds had significantly higher conduction velocity (12.6±4.9?cm/s) and contractile stress (0.79±0.13 mN/mm(2)) than gelatin/chitosan scaffolds. In summary, NRVM cultured on heart matrix scaffold showed improvements in contractile and electrophysiological function. PMID:24433519

Pok, Seokwon; Benavides, Omar M; Hallal, Patrick; Jacot, Jeffrey G

2014-07-01

393

A monoclonal antibody that specifically binds chitosan in vitro and in situ on fungal cell walls.  

PubMed

We report the generation of the first monoclonal antibody that specifically binds to the polysaccharide chitosan. Mice were immunized with a mixture of chitosans, and hybridoma clones were screened for specific binders resulting in the isolation of a single clone secreting a chitosan-specific IgM, mAbG7. In ELISAs, the antibody can bind to chitosans of varying composition, but demonstrates the highest affinity for chitosans with lower degrees of acetylation (DA) and very poor binding to chitin. We tested the ability of the antibody to bind to chitosan in situ, using preparations of fungal cell walls. Immunofluorescence microscopy confirmed that the antibody bound strongly to the cell walls of fungi with high levels of chitosan, whereas poor staining was observed in those species with cell walls of predominantly chitin or cellulose. The potential use of this antibody for the detection of fungal contamination and the protection of plants against fungal pathogens is discussed. PMID:20798578

Schubert, Max; Agdour, Siham; Fischer, Rainer; Olbrich, Yvonne; Schinkel, Helga; Schillberg, Stefan

2010-08-01

394

The green adsorption of chitosan tripolyphosphate nanoparticles on cotton fiber surfaces.  

PubMed

Chitosan nanoparticles (chitosan NP) were effectively incorporated onto cotton fiber surfaces during a green adsorption without any cross-linking agents in this work. The interactions between cotton fibers and chitosan NP during the green adsorption were investigated by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), thermogravimetric-derivative thermogravimetry (TG-DTG) and scanning electron microscopy (SEM) in detail. The results indicated that the intermolecular hydrogen bond interactions exited between the hydroxyl groups of cotton fibers and the amino groups of chitosan NP, and progressively enhanced with the increase in chitosan NP mass concentrations. After chitosan NP adsorption, the acidity of fibers augmented and the crystallinity index of fibers declined owing to the increasing interactions. In addition, the hydrophobic interactions occurred between chitosan NP and crystalline cotton fibers, thereby resulting in the preferential adsorption onto the hydrophobic (200) crystallographic plane. PMID:24299843

Wang, Mingxi; She, Yuanbin; Xiao, Zuobing; Hu, Jing; Zhou, Rujun; Zhang, Jia

2014-01-30

395

Physically cross-linked chitosan hydrogels as topical vehicles for hydrophilic drugs.  

PubMed

Physically cross-linked chitosan hydrogels with lauric, myristic, palmitic or stearic acid were prepared by freeze-drying and have been studied for topical use. This study selected propranolol hydrochloride as a hydrophilic model drug to design a transdermal delivery system. We evaluated the effect of the nature of the cross-linker on drug permeation through porcine skin and the main permeation parameters (diffusion coefficient, flux and lag time) were calculated. All the chitosan hydrogels analysed provided more transcutaneous permeation of propranolol hydrochloride than the corresponding solution of the commercial drug. Among the different chitosan vehicles, chitosan-laurate and chitosan-myristate hydrogels enhanced lyophilised drug diffusion through the skin with respect to chitosan-palmitate and chitosan-stearate hydrogels. This can been explained by the interaction of the hydrogels with the stratum corneum, increasing the solubility of the drug in the skin. PMID:12495547

Cerchiara, T; Luppi, B; Bigucci, F; Orienti, I; Zecchi, V

2002-11-01

396

[Effect of the molecular weight of chitosan on its antiviral activity in plants].  

PubMed

The effect of the molecular weight of chitosan on its ability to suppress systemic infection of bean mild mosaic virus in bean (Phasoleus vulgaris L.) plants was studied. The enzymatic hydrolysate of low-molecular-weight chitosan was successively fractionated by ultrafiltration through membranes with decreasing pore size. In total, four chitosan fractions with a weight-average molecular weight varying from 1.2 to 40.4 kDa were obtained. It was shown that the treatments of bean plants with these fractions (chitosan concentration, 10 or 100 microg/ml) inhibited virus accumulation and systemic propagation. The degree of chitosan-induced antiviral resistance increased as the molecular weight of chitosan decreased. The monomers comprising the chitosan molecule-glucosamine and N-acetylglucosamine--exhibited no antiviral activity. PMID:16761579

Kulikov, S N; Chirkov, S N; Il'ina, A V; Lopatin, S A; Varlamov, V P

2006-01-01

397

[Effect of chitosan derivatives on the development of phage infection in cultured Bacillus thuringiensis].  

PubMed

The influence of chitosan fragments with different degrees of polymerization and some chemical chitosan derivatives on the infection of Bacillus thuringiensis by phage 1-97A was studied. It was shown that chitosan inhibits phage infection and inactivates phage particles. The extent of inhibition of phage infection inversely depended on the degree of polymerization of chitosan fragments. On the contrary, the extent of inactivation of phage virulence was proportional to the degree of polymerization. Chitosan derivatives did not inhibit the growth of bacilli. Deaminated chitosan derivatives at a concentration of 100 mg/ml efficiently inhibited phage reproduction, exhibiting no correlation between the degree of deamination and antiviral activity. The anionic derivative chitosan sulfate and N-succinate-6-O-sulfate did not inactivate phage, did not influence bacterial growth, and did not inhibit the process of viral infection. PMID:10776629

Kochkina, Z M; Chirkov, S N

2000-01-01

398

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

PubMed

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

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

2014-05-01

399

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

400

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

401

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

402

Fabrication of photo-crosslinked chitosan- gelatin scaffold in sodium alginate hydrogel for chondrocyte culture.  

PubMed

Photo-crosslinked chitosan-gelatin scaffolds were fabricated and applied for chondrocyte culture in vitro. Photocurable methacryloyl chitosan was synthesized and characterized by FTIR and 1H NMR, respectively. Microstructure and mechanical properties of the chitosan-gelatin scaffold treated with or without EDC as crosslinking agent were analyzed by scanning electronic microscopy (SEM), compression and viscoelastic measurement. It is demonstrated that EDC-treated chitosan-gelatin scaffold possesses better porous structure and improved mechanical properties. Photo-crosslinked chitosan-gelatin scaffold could be further integrated in sodium alginate hydrogel using calcium chloride to support proliferation of chondrocytes for over 21 days and maintain spherical phenotype, as evaluated by AlamarBlue assay and SEM, respectively, implying that the chitosan-gelatin-hydrogel system exhibits great cyto-biocompatibility. Results of this study show that photo-crosslinked chitosan-gelatin scaffold in sodium alginate hydrogel is suited as a scaffold candidate for cartilage tissue engineering. PMID:24211948

Zhao, Peng; Deng, Cuijun; Xu, Hongzhen; Tang, Xing; He, Hailong; Lin, Chao; Su, Jiansheng

2014-01-01

403

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

PubMed

Previous research has shown that soluble protein recovery by chitosan (Chi) complexes with polyanions such as alginate (Alg) is more effective than using chitosan alone. In this study, Chi-Alg complexes were used to recover soluble proteins from surimi wash water (SWW) slightly acidified to pH 6. Six Chi samples differing in molecular weight (MW) and degree of deacetylation (DD) were used at 20, 40 and 100mg/L SWW Chi-Alg complexes prepared with a Chi:Alg mixing ratio previously optimized (MR=0.2). FTIR analysis of the solids recovered revealed the three characteristic amide bands observed in the same region for untreated SWW confirming protein adsorption by Chi-Alg. The superior effectiveness of Chi complexes was confirmed but differences among chitosan types could not be correlated to MW and DD. Experimental Chi samples with 94%, 93%, 75% and 93% DD and 22, 47, 225 and 3404 x 10(3)Da, respectively, showed 73-76% protein adsorption while a commercial chitosan sample with 84% DD and 3832 x 10(3)Da had 74-83% protein adsorption. An experimental chitosan, SY-1000 with 94% DD and 1.5 x 10(6)Da, showed the highest protein adsorption (79-86%) and turbidity reduction (85-92%) when used at 20mg/L SWW. PMID:16580193

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

2007-02-01

404

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

PubMed

Chitosan (deacetylation=75-85%) and sodium tripolyphosphate (TPP) solutions were observed to undergo spontaneous coacervation transition or nanoparticle formation depending on the chitosan concentration and the volumetric mixing ratio [chitosan/TPP]. Three distinct conditions have been identified: (i) [chitosan]chitosan/TPP]chitosan]chitosan/TPP]>or=2 and 3.5chitosan nanoparticles and (iii) 0.5chitosan]chitosan/TPP]chitosan nanoparticles had typical diameter in the range approximately 150-350 nm depending on polymer concentration and chitosan/TPP mixing ratio, which reduced by approximately 40% when polyethylene glycol (PEG) was added to these solutions. The long-time light scattering probing of the solutions revealed that residual interactions continuously produced soluble intermolecular complexes over extended period of time, a process that enabled the generation of coacervate droplets seamlessly. The coacervates (formed spontaneously or induced), and chitosan and chitosan-PEG nanoparticles, were used for encapsulating hydrophobic protein synthesis inhibitor model drug cycloheximide. The comparative in vitro release profiles in phosphate buffer and simulated intestinal fluid was monitored at 37 degrees C. PMID:20674298

Kaloti, Mandeep; Bohidar, H B

2010-11-01

405

C3, C5, and factor B bind to chitosan without complement activation.  

PubMed

Chitosan is a polycationic and biocompatible polysaccharide composed of glucosamine and N-acetyl glucosamine that is chemotactic for neutrophils and stimulates wound repair through mechanisms that remain unclear. It was previously shown that chitosan depletes complement proteins from plasma, suggesting that chitosan activates complement. Complement activation leads to cleavage of C5 to produce C5a, a neutrophil chemotactic factor. Here, we tested the hypothesis that chitosan generates C5a in human whole blood, citrated plasma, and serum. C5a fragment appeared in coagulating whole blood, and mixtures of chitosan-glycerol phosphate/whole blood, in parallel with platelet and thrombin activation. However, in plasma and serum, thrombin and chitosan-GP failed to generate C5a, although native C3, C5, and factor B adsorbed noncovalently to insoluble chitosan particles incubated in citrated plasma, serum, EDTA-serum and methylamine-treated plasma. By surface plasmon resonance, pure C3 adsorbed to chitosan. The profile of serum factors associating with chitosan was consistent with a model in which anionic blood proteins with a pI lower than the pK(0) 6.78 of chitosan (the upper limit of chitosan pK(a)) associate electrostatically with cationic chitosan particles. Zymosan, a yeast ghost particle, activated complement in serum and citrated plasma, but not in EDTA-serum or methylamine plasma, to generate fluid-phase C5a, while C3b formed covalent cross-links with zymosan-associated proteins and became rapidly cleaved to iC3b, with factor Bb stably associated. These data demonstrate that chitosan is a nonreactive biomaterial that does not directly activate complement, and provide a novel basis for predicting anionic serum protein-chitosan interactions. PMID:19927329

Marchand, C; Bachand, J; Périnêt, J; Baraghis, E; Lamarre, M; Rivard, G E; De Crescenzo, G; Hoemann, C D

2010-06-15

406

Desulfurization of gasoline using molecularly imprinted chitosan as selective adsorbents.  

PubMed

For desulfurization of gasoline, novel chitosan-based molecularly imprinted polymer (MIP) was prepared by cross-linking chitosan with epichlorohydrin in the presence of dibenzothiophene (DBT) as the template. The influence of cross-linking ratio on the specific adsorption was evaluated. The effects of the types and the amounts of porogen on selectivity of the chitosan MIP were also examined. Results showed that MIP has a higher recognition property to DBT. The maximum rebinding capacities of the MIP reached 22.69 mg g(-1) in the model solution. The adsorption behaviors of the MIP including adsorption kinetics, isotherms, and thermodynamic parameters were investigated and the experimental data agreed well with the Langmuir model. The dynamical adsorption behaved in first-order kinetics. Negative values for the Gibbs free energy showed that the adsorptions were spontaneous processes. The MIP was further used to selectively adsorb organosulfur from gasoline. PMID:19050832

Chang, Yonghui; Zhang, Lei; Ying, Hanjie; Li, Zhenjiang; Lv, Hao; Ouyang, Pingkai

2010-01-01

407

Electrospun nanofibrous chitosan membranes modified with polyethyleneimine for formaldehyde detection.  

PubMed

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

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

2014-08-01

408

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

409

Evaluation of chitosan gel as antibiotic and photosensitizer delivery.  

PubMed

This work suggests the use of chitosan gel imbued with the photosensitizer Photogem and with the antibiotic Tetraclin as a possible drug delivery system. The results reveal a decrease in the photosensitizer level of toxicity. Besides, the interaction between Photogem and chitosan gel causes a red shift in the photosensitizer spectrum, increasing its absorption in the therapeutic window (600-700 nm). These characteristics indicate this compound as a promising natural polymer-based photosensitizer carrier for photodynamic therapy. In summary, our results show that pure and doped chitosan gel may have potential application for antimicrobial action, being an excellent alternative when local control of the drug administration, provided by the gel, is required. PMID:18712618

Fontana, Carla Raquel; dos Santos, David Sotero; Bosco, Joseane Maria; Spolidorio, Denise M; Chiérici Marcantonio, Rosemary Adriana

2008-09-01

410

Production of chitosan pellets by extrusion/spheronization.  

PubMed

Chitosan pellets were successfully prepared using the extrusion/spheronization technology. Microcrystalline cellulose was used as additive in concentrations from 70 to 0%. The powder mixtures were extruded using water and diluted acetic acid solution in different powder to liquid ratios. The effects on bead formation using water and different acetic acid concentrations and solution quantities were analysed. Also, the morphological and mechanical characteristics of the obtained beads were investigated. With demineralized water as granulation fluid, pellets with a maximum of 50% (m/m) of chitosan could be produced. The mass fraction of chitosan within the pellets could be increased to 100% by using diluted acetic acid for the granulation step. PMID:14729086

Steckel, H; Mindermann-Nogly, F

2004-01-01

411

Chitosan microparticles as injectable scaffolds for tissue engineering  

Microsoft Academic Search

The use of chitosan microparticles as injectable carriers for cell\\u000d\\u000a transplantation represents a promising alternative to avoid the\\u000d\\u000a drawbacks of the implantation of other forms of three-dimensional (3D)\\u000d\\u000a scaffolds seeded with cells. In this study, a 3D construct is obtained\\u000d\\u000a in vitro by combining chitosan microparticles crosslinked with genipin\\u000d\\u000a and goat bone marrow stromal cells (GBMCs). Cell viability and the

Dunia Mercedes Garcia Cruz; Jorge Luis Escobar Ivirico; Manuela M. Gomes; Jose Luis Gomez Ribelles; Manuel Salmeron Sanchez; Rui L. Reis; Joao F. Mano

2008-01-01

412

A novel hydrogel crosslinked hyaluronan with glycol chitosan.  

PubMed

A novel hydrogel was prepared by crosslinking hyaluronan with glycol chitosan in aqueous solution using water soluble carbodiimide at nearly neutral pH and room temperature. The products can be easily formulated into injectable gels, various films, membranes and sponges for soft tissue augmentation, viscosupplementation, drug delivery, preventing adhesion of post operation, wound dressing and tissue engineering scaffolds. The said hydrogel has high water adsorption property and biostability. Rheololgical results of the gel showed a soft and viscoelastic structure. FTIR further confirmed the formation of amide bonds between carboxyl groups of hyaluronan and amine groups of glycol chitosan and no N-acylurea and other derivatives were identified. PMID:17143757

Wang, Wei

2006-12-01

413

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

414

Graphene\\/AuNPs\\/chitosan nanocomposites film for glucose biosensing  

Microsoft Academic Search

A novel glucose biosensor based on immobilization of glucose oxidase in thin films of chitosan containing nanocomposites of graphene and gold nanoparticles (AuNPs) at a gold electrode was developed. The resulting graphene\\/AuNPs\\/chitosan composites film exhibited good electrocatalytical activity toward H2O2 and O2. The wide linear response to H2O2 ranging from 0.2 to 4.2mM (R=0.998) at ?0.2V, high sensitivity of 99.5?AmM?1cm?2

Changsheng Shan; Huafeng Yang; Dongxue Han; Qixian Zhang; Ari Ivaska; Li Niu

2010-01-01

415

Chitosan: Its Applications in Drug-Eluting Devices  

Microsoft Academic Search

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

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

416

Chitosan/gelatin blends for biomedical applications.  

PubMed

Blends between chitosan (CS) and gelatin (G) with various compositions (CS/G 0/100 20/80, 40/60, 60/40, 100/0 w/w) were produced as candidate materials for biomedical applications. Dehydro-thermal crosslinking was adopted to promote the formation of amide and ester bonds between the macromolecules ((CS/G)-t). The effect of composition and crosslinking on the physico-chemical properties of the samples was evaluated by scanning electron microscopy, thermogravimetry, contact angle measurements, dissolution and swelling tests. Mechanical properties of (CS/G)-t samples were also determined through stress-strain and creep-recovery tests. The elastic moduli of dry blend samples showed a positive deviation from the additive law of the in-series model, because of interactions and/or chemical bonds between components. The comparison between the elastic moduli of wet samples and those of different human tissues showed that (CS/G)-t substrates can be suitable for soft-tissue reconstruction. (CS/G)-t two-dimensional scaffolds were fabricated by micro-molding, based on the use of a polydimethylsiloxane mould to create patterns with micro-scale resolution on cast films. Biocompatibility of (CS/G)-t samples was studied by means of cell tests using NIH-3T3 fibroblasts. Finally, the evaluation of the affinity of (CS/G)-t samples towards neuroblastoma cells adhesion and proliferation was performed, showing promising results for the blend containing 80 wt % gelatin. PMID:17969018

Pulieri, Ettore; Chiono, Valeria; Ciardelli, Gianluca; Vozzi, Giovanni; Ahluwalia, Arti; Domenici, Claudio; Vozzi, Federico; Giusti, Paolo

2008-08-01

417

Sol/gel transition of chitosan solutions.  

PubMed

This work studies the occurrence of sol/gel transition and the gel rheology for chitosan solution under various conditions. Experiments were conducted in an oscillatory shear apparatus with small amplitude, using a Rheometrics SR-5 rheometer, with Couette and parallel plate geometries. The experimental results demonstrate that the sol/gel transition concentration and the elastic modulus (G') for CS gel decrease as the pH value and the molecular weight (Mw) increase. However, the sol/gel transition concentration and G' became independent of Mw when Mw exceeded a threshold. The higher ionization constant, Kp, is responsible for the higher sol/gel transition concentration in a formic acid solution than in an acetic acid solution with equivalent molar concentration. The elastic modulus G' of a CS gel increases with temperature, which relationship differs from that for many polysaccharides, and can be understood through classical rubber elastic theory. Finally, a gel whose concentration was barely above the sol/gel point exhibited aging, and its G' and G" declined rather than increase with time, accompanied by a reversal from the sol/gel state back to the sol state. This is an uncommon aging behavior for a polysaccharide and a detailed explanation is provided. PMID:16370243