These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

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

2

Structure and properties of gadolinium loaded calcium phosphate glasses  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

3

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

E-print Network

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

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

2014-01-01

4

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

E-print Network

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

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

2014-02-27

5

A new gadolinium-loaded liquid scintillator for reactor neutrino detection  

NASA Astrophysics Data System (ADS)

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

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

2008-01-01

6

Chitosan-DNA nanoparticles delivered by intrabiliary infusion enhance liver-targeted gene delivery  

PubMed Central

The goal of this study was to examine the efficacy of liver-targeted gene delivery by chitosan-DNA nanoparticles through retrograde intrabiliary infusion (RII). The transfection efficiency of chitosan-DNA nanoparticles, as compared with PEI-DNA nanoparticles or naked DNA, was evaluated in Wistar rats by infusion into the common bile duct, portal vein, or tail vein. Chitosan-DNA nanoparticles administrated through the portal vein or tail vein did not produce detectable luciferase expression. In contrast, rats that received chitosan-DNA nanoparticles showed more than 500 times higher luciferase expression in the liver 3 days after RII; and transgene expression levels decreased gradually over 14 days. Luciferase expression in the kidney, lung, spleen, and heart was negligible compared with that in the liver. RII of chitosan-DNA nanoparticles did not yield significant toxicity and damage to the liver and biliary tree as evidenced by liver function analysis and histopathological examination. Luciferase expression by RII of PEI-DNA nanoparticles was 17-fold lower than that of chitosan-DNA nanoparticles on day 3, but it increased slightly over time. These results suggest that RII is a promising routine to achieve liver-targeted gene delivery by non-viral nanoparticles; and both gene carrier characteristics and mode of administration significantly influence gene delivery efficiency. PMID:17369870

Dai, Hui; Jiang, Xuan; Tan, Geoffrey CY; Chen, Yong; Torbenson, Michael; Leong, Kam W; Mao, Hai-Quan

2006-01-01

7

Hierarchical targeted hepatocyte mitochondrial multifunctional chitosan nanoparticles for anticancer drug delivery.  

PubMed

The overwhelming majority of drugs exert their pharmacological effects after reaching their target sites of action, however, these target sites are mainly located in the cytosol or intracellular organelles. Consequently, delivering drugs to the specific organelle is the key to achieve maximum therapeutic effects and minimum side-effects. In the work reported here, we designed, synthesized, and evaluated a novel mitochondrial-targeted multifunctional nanoparticles (MNPs) based on chitosan derivatives according to the physiological environment of the tumor and the requirement of mitochondrial targeting drug delivery. The intelligent chitosan nanoparticles possess various functions such as stealth, hepatocyte targeting, multistage pH-response, lysosomal escape and mitochondrial targeting, which lead to targeted drug release after the progressively shedding of functional groups, thus realize the efficient intracellular delivery and mitochondrial localization, inhibit the growth of tumor, elevate the antitumor efficacy, and reduce the toxicity of anticancer drugs. It provides a safe and efficient nanocarrier platform for mitochondria targeting anticancer drug delivery. PMID:25818430

Chen, Zhipeng; Zhang, Liujie; Song, Yang; He, Jiayu; Wu, Li; Zhao, Can; Xiao, Yanyu; Li, Wei; Cai, Baochang; Cheng, Haibo; Li, Weidong

2015-06-01

8

Application of chitosan-based nanocarriers in tumor-targeted drug delivery.  

PubMed

Cancer is one of the major malignant diseases in the world. Current anti tumor agents are restricted during the chemotherapy due to their poor solubility in aqueous media, multidrug resistance problems, cytotoxicity, and serious side effects to healthy tissues. Development of targeted drug nanocarriers would enhance the undesirable effects of anticancer drugs and also selectively deliver them to cancerous tissues. Variety of nanocarriers such as micelles, polymeric nanoparticles, liposomes nanogels, dendrimers, and carbon nanotubes have been used for targeted delivery of anticancer agents. These nanocarriers transfer loaded drugs to desired sites through passive or active efficacy mechanisms. Chitosan and its derivatives, due to their unique properties such as hydrophilicity, biocompatibility, and biodegradability, have attracted attention to be used in nanocarriers. Grafting cancer-specific ligands onto the Chitosan nanoparticles, which leads to ligand-receptor interactions, has been successfully developed as active targeting. Chitosan-conjugated components also respond to external or internal physical and chemical stimulus in targeted tumors that is called environment triggers. In this study, mechanisms of targeted tumor deliveries via nanocarriers were explained; specifically, chitosan-based nanocarriers in tumor-targeting drug delivery were also discussed. PMID:25385004

Ghaz-Jahanian, Mohammad Ali; Abbaspour-Aghdam, Farzin; Anarjan, Navideh; Berenjian, Aydin; Jafarizadeh-Malmiri, Hoda

2015-03-01

9

Reactor Anti-Neutrino Oscillations and Gadolinium Loaded Super-Kamiokande Detector  

E-print Network

We explore the potential of measuring the solar neutrino oscillation parameters in the proposed gadolinium loaded Super-Kamiokande (SK-Gd) detector. Gadolinium dissolved in water can detect neutrons much more efficiently than pure water. This imparts the detector the ability to observe electron type antineutrinos, transforming Super-Kamiokande into a huge reactor antineutrino detector with an event rate approximately 43 times higher than that observed in KamLAND. We simulate the reactor antineutrino data expected in this high statistics detector. We use these prospective data to study the precision with which the solar neutrino oscillation parameters, $\\Delta m^2_{\\odot}$ and $\\sin^2\\theta_{\\odot}$, can be determined i) with the SK-Gd detector, and ii) by combining the SK-Gd data with the global data on solar neutrino oscillations. For comparison and completeness the allowed regions of $\\Delta m^2_{\\odot}$ and $\\sin^2\\theta_{\\odot}$, expected to be obtained from the data of the solar neutrino and KamLAND experiments, are also presented.

Sandhya Choubey; S. T. Petcov

2004-08-13

10

Fabrication of lactobionic-loaded chitosan microcapsules as potential drug carriers targeting the liver.  

PubMed

This paper demonstrates a general approach for fabrication of lactobionic chitosan microcapsules using layer-by-layer assembly via click chemistry. Chitosan was selectively modified with either azide (CHI-Az) or alkyne (CHI-Alk) groups. The growth of the CHI-Az/CHI-Alk click multilayer was studied experimentally by multilayer assembly on planar supports. Linear buildup of the film was observed. The chitosan click capsules were also analyzed with confocal laser scanning microscopy and transmission electron microscopy. Capsules were found to have regular spherical shapes. In addition, (CHI-Az/CHI-Alk)-coated particles were modified with fluorescein isothiocyanate to ensure that the particles can be easily post-functionalized. Finally, lactobionic acid was conjugated onto the (CHI-Az/CHI-Alk)-coated particles and the lactobionic particles exhibited hepatoma cell (HepG2) targeting behavior. PMID:21130904

Zhang, Jing; Li, Cao; Xue, Zhi-Yuan; Cheng, Hai-Wei; Huang, Fu-Wei; Zhuo, Ren-Xi; Zhang, Xian-Zheng

2011-04-01

11

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

Microsoft Academic Search

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

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

12

Development and evaluation of chitosan and chitosan/Kollicoat® Smartseal 30 D film-coated tablets for colon targeting.  

PubMed

The aim of the present study was to develop film-coated tablets which release a minor amount of the active pharmaceutical ingredient (API) into the stomach and small intestine, yet show a sharp increase of drug release in the colon. Tablets containing the model drug Diclofenac-Na, microcrystalline cellulose as a filler (MT), as well as tablets consisting of Ludiflash® (LT), both were used as tablet cores, respectively. Either chitosan (CHI) alone or different ratios of chitosan and Kollicoat® Smartseal 30 D (KCSS) were applied onto these cores. The resulting film-coated tablets were analyzed for swelling, drug dissolution and stability. In order to clarify whether the colon release is mainly enzyme-driven or pressure-controlled, the coated tablets were both tested in the colon microflora test (CMT), which simulates the enzyme environment within the colon, and using a bio-relevant dissolution apparatus mimicking the intraluminal pressures and stress conditions present in the gastrointestinal tract (GIT). CHI/KCSS (25:75) coated LTs showed a pressure-controlled site-specific drug release in the large intestine, while remaining intact in the upper GIT. CHI as well as CHI/KCSS (25:75) applied onto MTs, remained stable during the entire simulated bio-relevant dissolution transit of the GIT, but showed enzymatically controlled colon targeting in the CMT. These results could be confirmed for CHI/KCSS (25:75) film-coated MTs top-coated with an additional hydroxypropylmethylcellulose (HPMC) layer and an Eudragit L 30 D-55 (EUL) layer to avoid the dissolution in the fasting stomach. PMID:25301294

Drechsler, Michael; Garbacz, Grzegorz; Thomann, Ralf; Schubert, Rolf

2014-11-01

13

Dendritic Cell Targeted Chitosan Nanoparticles for Nasal DNA Immunization against SARS CoV Nucleocapsid Protein  

PubMed Central

This work investigates the formulation and in vivo efficacy of dendritic cell (DC) targeted plasmid DNA loaded biotinylated chitosan nanoparticles for nasal immunization against nucleocapsid (N) protein of severe acute respiratory syndrome coronavirus (SARS-CoV) as antigen. The induction of antigen-specific mucosal and systemic immune response at the site of virus entry is a major challenge for vaccine design. Here, we designed a strategy for non-invasive receptor mediated gene delivery to nasal resident DCs. The pDNA loaded biotinylated chitosan nanoparticles were prepared using a complex coacervation process and characterized for size, shape, surface charge, plasmid loading and protection against nuclease digestion. The pDNA loaded biotinylated chitosan nanoparticles were targeted with bifunctional fusion protein (bfFp) vector for achieving DC selective targeting. The bfFp is a recombinant fusion protein consisting of truncated core-streptavidin fused with anti-DEC-205 single chain antibody (scFv). The core-streptavidin arm of fusion protein binds with biotinylated nanoparticles, while anti-DEC-205 scFv imparts targeting specificity to DC DEC-205 receptor. We demonstrate that intranasal administration of bfFp targeted formulations along with anti-CD40 DC maturation stimuli enhanced magnitude of mucosal IgA as well as systemic IgG against N protein. The strategy led to the detection of augmented levels of N protein specific systemic IgG and nasal IgA antibodies. However, following intranasal delivery of naked pDNA no mucosal and systemic immune responses were detected. A parallel comparison of targeted formulations using intramuscular and intranasal route showed that the intramuscular route is superior for induction of systemic IgG responses compared with the intranasal route. Our results suggest that targeted pDNA delivery through non-invasive intranasal route can be a strategy for designing low-dose vaccines. PMID:22356166

Raghuwanshi, Dharmendra; Mishra, Vivek; Das, Dipankar; Kaur, Kamaljit; Suresh, Mavanur R.

2012-01-01

14

Chitosan nanoparticles for targeting and sustaining minoxidil sulphate delivery to hair follicles.  

PubMed

This work developed minoxidil sulphate-loaded chitosan nanoparticles (MXS-NP) for targeted delivery to hair follicles, which could sustain drug release and improve the topical treatment of alopecia. Chitosan nanoparticles were obtained using low-molecular weight chitosan and tripolyphosphate as crosslink agent. MXS-NP presented a monomodal distribution with hydrodynamic diameter of 235.5±99.9nm (PDI of 0.31±0.01) and positive zeta potential (+38.6±6.0mV). SEM analysis confirmed nanoparticles average size and spherical shape. A drug loading efficiency of 73.0±0.3% was obtained with polymer:drug ratio of 1:1 (w/w). Drug release through cellulose acetate membranes from MXS-NP was sustained in about 5 times in comparison to the diffusion rate of MXS from the solution (188.9±6.0?g/cm(2)/h and 35.4±1.8?g/cm(2)/h). Drug permeation studies through the skin in vitro, followed by selective recovery of MXS from the hair follicles, showed that MXS-NP application resulted in a two-fold MXS increase into hair follicles after 6h in comparison to the control solution (5.9±0.6?g/cm(2) and 2.9±0.8?g/cm(2)). MXS-loading in nanoparticles appears as a promising and easy strategy to target and sustain drug delivery to hair follicles, which may improve the topical treatment of alopecia. PMID:25647618

Matos, Breno Noronha; Reis, Thaiene Avila; Gratieri, Taís; Gelfuso, Guilherme Martins

2015-04-01

15

Folate mediated in vitro targeting of depolymerised trimethylated chitosan having arginine functionality.  

PubMed

Delivery vectors having targeting ligands provide an impending impact on cancer gene therapy. Our work focuses on folate mediated targeting induced by conjugating poly(ethylene glycol)-folate (PEG-FA) with arginine modified chitosan polymer having low molecular weight of 15 kDa and high degree of quaternization (ATFP15H). The ATFP15H derivative on condensation with plasmid DNA formed nanoparticles with core shell nanostructure. It also affirmed good buffering capacity. The derivative was found to protect DNA from DNase I degradation and also from disassembly in presence of negatively charged plasma proteins. It exhibited blood compatibility in terms of percentage hemolysis, erythrocyte aggregation and also by platelet activation. At a concentration of 10 microg, the capability of the derivative to enhance cell growth at normal cell growing conditions was observed. The transfection efficiency was also found to be comparable to PEI when transfected in KB cell line, which over expressed the folate receptor (FR) in presence of 10% fetal bovine serum (FBS). On comparison with native chitosan and trimethylated chitosan, ATFP15H derivative exhibited high cellular uptake and nuclear localization due to the superior colloidal stability attained on conjugation with polyethylene glycol. This has been ascertained by flow cytometry and YOYO labeling of plasmid DNA. PMID:20580766

Morris, Viola B; Sharma, Chandra P

2010-08-15

16

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

17

Targeted delivery of vaccine to dendritic cells by chitosan nanoparticles conjugated with a targeting Peptide ligand selected by phage display technique.  

PubMed

The paper presents a novel dendritic cells (DC)-targeting peptide, TPAFRYS (TP) identified by phage display technique and conjugated to chitosan in order to develop an efficient DC-targeting vaccine delivery carrier. TP-conjugated chitosan nanoparticles (TPC-NPs) were prepared with ovalbumin (OVA) as a model vaccine by ionic gelation. Flow cytometry and immunocytochemistry studies demonstrated the higher targeting ability of TPC-NPs to DCs in compared to chitosan NPs. Moreover, TPC-NPs exhibited higher targeting specificity in DCs than macrophage and myoblasts. Furthermore, immunization of mice with OVA-loaded TPC-NPs enhanced OVA-specific serum IgG and IgG isotype antibodies production. Thus, DC-targeting strategy demonstrates a potential approach to enhance the effectiveness of vaccines. PMID:25393207

Jung, Su-Na; Kang, Sang-Kee; Yeo, Guen-Hye; Li, Hai-Ying; Jiang, Tao; Nah, Jae-Woon; Bok, Jin-Duck; Cho, Chong-Su; Choi, Yun-Jaie

2015-03-01

18

Design and synthesis of dual-ligand modified chitosan as a liver targeting vector.  

PubMed

Vector plays an important role in hepatic targeted drug delivery system. In this study, a novel material as a liver targeting vector, dual-ligand modified chitosan (GCGA) composed of chitosan (CTS), glycyrrhetinic acid (GA) and lactobionic acid (LA), was designed and synthesized by an orthogonal experiment with two-step synthesis under mild conditions. The synthesized final product was characterized and confirmed by FTIR and (1)H-NMR spectroscopy, and DS of GA and LA in CTS were measured to be 13.77 and 16.74 mol% using (1)H-NMR, respectively. The cytotoxicity of CTS and GCGA was concentration dependent which was inverse proportion to the cell viability by MTT assay using L929 cell line, and inhibitory concentration 50% (IC50) was 0.2 mg/ml for GCGA. The in vitro targeting efficiency and the in vitro cellular uptake were investigated. Compared with CTS NPs and GA-CTS NPs, GCGA NPs showed good cell specificity to BEL-7402 cells via the dual-ligand-receptor-mediated recognition, leading to a higher affinity to BEL-7402 cells. The results suggested that GCGA described here has the potential to be used as an effective vector for hepatic targeted drug therapy. PMID:22105225

Chen, Houxiang; Li, Min; Wan, Tao; Zheng, Qichang; Cheng, Mingrong; Huang, Shiqi; Wang, Yong

2012-02-01

19

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

PubMed

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

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

2013-10-01

20

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

PubMed

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

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

2012-01-10

21

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

PubMed

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

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

2014-12-01

22

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

PubMed

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

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

2011-06-13

23

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

PubMed Central

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

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

2012-01-01

24

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

PubMed

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

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

2014-08-01

25

Microencapsulation of coupled folate and chitosan nanoparticles for targeted delivery of combination drugs to colon.  

PubMed

Abstract Folate-chitosan nanoparticles, co-loaded with 5-fluourouacil (5-FU) and leucovorin (LV) and prepared by ionic gelation technology were physically microencapsulated by enteric polymer using a solvent evaporation method. Average particle size of the microencapsulated particles was in the range of 15 to 35?µm. High drug encapsulation efficiency was obtained for both 5-FU and LV in the microencapsulated particles. Both drugs were in amorphous state in the microencapsulated particles. By enteric coating, excellent pH-dependent release profile was achieved and no drug release was observed in simulated gastric and intestinal fluids. However, when the pH value reached the soluble threshold of Eudragit S-100, a constant and slow drug release was observed. The results indicated that these microencapsulated particles are a promising vehicle for selectively targeting drugs to colon in the chemotherapy of colon cancer. PMID:25198909

Li, Puwang; Yang, Ziming; Wang, Yichao; Peng, Zheng; Li, Sidong; Kong, Lingxue; Wang, Qinghuang

2014-09-01

26

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

PubMed

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

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

2014-10-01

27

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

28

Fabrication of lactobionic-loaded chitosan microcapsules as potential drug carriers targeting the liver  

Microsoft Academic Search

This paper demonstrates a general approach for fabrication of lactobionic chitosan microcapsules using layer-by-layer assembly via click chemistry. Chitosan was selectively modified with either azide (CHI-Az) or alkyne (CHI-Alk) groups. The growth of the CHI-Az\\/CHI-Alk click multilayer was studied experimentally by multilayer assembly on planar supports. Linear buildup of the film was observed. The chitosan click capsules were also analyzed

Jing Zhang; Cao Li; Zhi-Yuan Xue; Hai-Wei Cheng; Fu-Wei Huang; Ren-Xi Zhuo; Xian-Zheng Zhang

2011-01-01

29

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

Microsoft Academic Search

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

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

2001-01-01

30

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

Microsoft Academic Search

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

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

2000-01-01

31

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

PubMed

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

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

2006-05-01

32

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

PubMed

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

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

2014-03-10

33

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

PubMed

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

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

2010-12-01

34

High molecular weight chitosan derivative polymeric micelles encapsulating superparamagnetic iron oxide for tumor-targeted magnetic resonance imaging  

PubMed Central

Magnetic resonance imaging (MRI) contrast agents based on chitosan derivatives have great potential for diagnosing diseases. However, stable tumor-targeted MRI contrast agents using micelles prepared from high molecular weight chitosan derivatives are seldom reported. In this study, we developed a novel tumor-targeted MRI vehicle via superparamagnetic iron oxide nanoparticles (SPIONs) encapsulated in self-aggregating polymeric folate-conjugated N-palmitoyl chitosan (FAPLCS) micelles. The tumor-targeting ability of FAPLCS/SPIONs was demonstrated in vitro and in vivo. The results of dynamic light scattering experiments showed that the micelles had a relatively narrow size distribution (136.60±3.90 nm) and excellent stability. FAPLCS/SPIONs showed low cytotoxicity and excellent biocompatibility in cellular toxicity tests. Both in vitro and in vivo studies demonstrated that FAPLCS/SPIONs bound specifically to folate receptor-positive HeLa cells, and that FAPLCS/SPIONs accumulated predominantly in established HeLa-derived tumors in mice. The signal intensities of T2-weighted images in established HeLa-derived tumors were reduced dramatically after intravenous micelle administration. Our study indicates that FAPLCS/SPION micelles can potentially serve as safe and effective MRI contrast agents for detecting tumors that overexpress folate receptors. PMID:25709439

Xiao, Yunbin; Lin, Zuan Tao; Chen, Yanmei; Wang, He; Deng, Ya Li; Le, D Elizabeth; Bin, Jianguo; Li, Meiyu; Liao, Yulin; Liu, Yili; Jiang, Gangbiao; Bin, Jianping

2015-01-01

35

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

PubMed Central

Background Targeting drugs to their sites of action to overcome the systemic side effects associated with most antineoplastic agents is still a major challenge in pharmaceutical research. In this study, the monoclonal antibody, trastuzumab, was used as a targeting agent in nanoparticles carrying the antitumor drug, doxorubicin, specifically to its site of action. Methods Chitosan-doxorubicin conjugation was carried out using succinic anhydride as a crosslinker. Trastuzumab was conjugated to self-assembled chitosan-doxorubin conjugate (CS-DOX) nanoparticles (particle size, 200 nm) via thiolation of lysine residues and subsequent linking of the resulted thiols to chitosan. Conjugation was confirmed by gel permeation chromatography, differential scanning calorimetry, Fourier transform infrared spectroscopy, and 1H nuclear magnetic resonance spectroscopy studies. Dynamic light scattering, transmission electron microscopy, and zeta potential determination were used to characterize the nanoparticles. Results CS-DOX conjugated nanoparticles had a spherical shape and smooth surface with a narrow size distribution and core-shell structure. Increasing the ratio of doxorubicin to chitosan in the conjugation reaction gave rise to a higher doxorubicin content but lower conjugation efficiency. Trastuzumab-decorated nanoparticles (CS-DOX-mAb) contained 47 ?g/mg doxorubicin and 33.5 ?g/mg trastuzumab. Binding of trastuzumab to the nanoparticles was further probed thermodynamically by isothermal titration calorimetry. Fluorescence microscopy demonstrated enhanced and selective uptake of CS-DOX-mAb by Her2+ cancer cells compared with nontargeted CS-DOX nanoparticles and free drug. Conclusion Antibody-conjugated nanoparticles were shown to discriminate between Her2+ and Her2? cells, and thus have the potential to be used in active targeted drug delivery, with reduction of drug side effects in Her2+ breast and ovarian cancers. PMID:21976974

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

2011-01-01

36

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

PubMed Central

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

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

2014-01-01

37

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 171.6 nm, 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 24 h 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

38

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

PubMed

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

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

2012-08-30

39

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

PubMed Central

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

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

2012-01-01

40

Chitosan–pectin polyelectrolyte complex as a carrier for colon targeted drug delivery  

PubMed Central

Objective The objective of present work was to prepare a polyelectrolyte complex (PEC) between chitosan (polycation) & pectin (polyanion) and to develop enteric coated tablets for colon delivery using the PEC. Methodology The PECs were prepared using different concentrations of chitosan and pectin. Drug loaded enteric coated tablets were prepared by wet granulation method using PEC to sustain the release at colon and coating was done with Eudragit S 100 to prevent the early release of the drug in stomach and intestine. Two independent variable, % PEC (chitosan/pectin) and % coating were optimized by 32 full factorial design. Statistical model were also used to supplement the optimization. DSC was performed to confirm the interaction between the polyions. Developed formulations were evaluated for physical appearance, weight variation, thickness, hardness, friability, % swelling, assay, in-vitro and ex-vivo drug release studies to investigate the PEC's ability to deliver the drug to colon. Ex-vivo release study using rat caecal content was also carried out on optimized formulation. Results and discussion DSC results confirmed chitosan/pectin interaction and subsequent formation of PEC. The optimized formulation containing 1.1% of PEC and 3% of coating showed highest swelling and release in alkaline pH mechanism of which was found to be microbial enzyme dependent degradation established by ex-vivo study using rat caecal content. PMID:24563596

Pandey, Sonia; Mishra, Ashish; Raval, Pooja; Patel, Hetal; Gupta, Arti; Shah, Dinesh

2013-01-01

41

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

PubMed

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

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

2011-07-01

42

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

NASA Astrophysics Data System (ADS)

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

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

2010-11-01

43

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

Microsoft Academic Search

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

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

2006-01-01

44

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

PubMed

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

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

2015-05-01

45

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

PubMed

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

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

2014-10-01

46

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

PubMed Central

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

Wang, Hao; Xu, Yongdong; Zhou, Xiao

2014-01-01

47

Docetaxel-loaded chitosan microspheres as a lung targeted drug delivery system: in vitro and in vivo evaluation.  

PubMed

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 µm); the encapsulation efficiency and drug loading of prepared microspheres were 88.1% ± 3.5% and 18.7% ± 1.2%, respectively. In vitro release indicated that the DTX microspheres had a well-sustained release efficacy and in vivo studies showed that the microspheres were found to release the drug to a maximum extent in the target tissue (lung). The prepared microspheres were found to possess suitable physico-chemical properties and the particle size range. The sustained release of DTX from microspheres revealed its applicability as drug delivery system to minimize the exposure of healthy tissues while increasing the accumulation of therapeutic drug in target sites. PMID:24577314

Wang, Hao; Xu, Yongdong; Zhou, Xiao

2014-01-01

48

Optimization of multifunctional chitosan-siRNA nanoparticles for oral delivery applications, targeting TNF-? silencing in rats.  

PubMed

Secretion of tumor necrosis factor-? (TNF-?) by macrophages plays a predominant role in the development and progression of various inflammatory diseases. In the current contribution, multifunctional nanoparticles (NPs) containing TNF-? siRNA targeting macrophages via oral administration were developed to knockdown TNF-? expression against acute hepatic injury in rats. Mannose-modified trimethyl chitosan-cysteine (MTC) NPs were prepared by self-assembly method (sa-MTC NPs), ionic gelation and siRNA entrapment method (en-MTC NPs), and ionic gelation and siRNA adsorption method (ad-MTC NPs). Among them, en-MTC NPs demonstrated the best stability against ionic challenges with desired siRNA integrity against nucleases. By targeting normal enterocytes and M cells that express mannose receptors, en-MTC NPs notably promoted intestinal absorption of siRNA in rats. They further facilitated siRNA internalization by rat peritoneal exudate cells (PECs) via lipid-raft involved endocytosis and macropinocytosis, thus inducing effective in vitro TNF-? knockdown. Orally delivered en-MTC NPs at a low siRNA dose of 50?g/kg inhibited systemic TNF-? production and decreased TNF-? mRNA levels in macrophage-enriched liver, spleen, and lung tissues, which consequently protected rats from acute hepatic injury. Therefore, the en-MTC NPs would provide an effective approach to orally deliver TNF-? siRNA for the anti-inflammatory therapy. PMID:25662912

He, Chunbai; Yin, Lichen; Song, Yudong; Tang, Cui; Yin, Chunhua

2015-04-15

49

Synthesis of a novel glycoconjugated chitosan and preparation of its derived nanoparticles for targeting HepG2 cells.  

PubMed

In the study, a novel chitosan (CS) derivative conjugated with multiple galactose residues in an antennary fashion (Gal-m-CS) was synthesized. A galactosylated CS (Gal-CS) was also prepared by directly coupling lactobionic acid on CS. Using an iontropic gelation method, CS and the synthesized Gal-CS and Gal-m-CS were used to prepare nanoparticles (CS, Gal-CS, and Gal-m-CS NPs) for targeting hepatoma cells. TEM examinations showed that the morphology of all three types of NPs was spherical in shape. No aggregation or precipitation of NPs in an aqueous environment was observed during storage for all studied groups, as a result of the electrostatic repulsion between the positively charged NPs. Little fluorescence was observed in HepG2 cells after incubation with the FITC-labeled CS NPs. The intensity of fluorescence observed in HepG2 cells incubated with the Gal-m-CS NPs was stronger than that incubated with the Gal-CS NPs. These results indicated that the prepared Gal-m-CS NPs had the highest specific interaction with HepG2 cells among all studied groups, via the ligand-receptor-mediated recognition. PMID:17316043

Mi, Fwu-Long; Wu, Yong-Yi; Chiu, Ya-Lin; Chen, Mei-Chin; Sung, Hsing-Wen; Yu, Shu-Huei; Shyu, Shin-Shing; Huang, Mei-Feng

2007-03-01

50

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

PubMed Central

Chitosan (CS) nanoparticles of thymoquinone (TQ) were prepared by the ionic gelation method and are characterized on the basis of surface morphology, in vitro or ex vivo release, dynamic light scattering, and X-ray diffractometry (XRD) studies. Dynamic laser light scattering and transmission electron microscopy confirmed the particle diameter was between 150 to 200 nm. The results showed that the particle size of the formulation was significantly affected by the drug:CS ratio, whereas it was least significantly affected by the tripolyphosphate:CS ratio. The entrapment efficiency and loading capacity of TQ was found to be 63.3% ± 3.5% and 31.23% ± 3.14%, respectively. The drug-entrapment efficiency and drug-loading capacity of the nanoparticles appears to be inversely proportional to the drug:CS ratio. An XRD study proves that TQ dispersed in the nanoparticles changes its form from crystalline to amorphous. This was further confirmed by differential scanning calorimetry thermography. The flat thermogram of the nanoparticle data indicated that TQ formed a molecular dispersion within the nanoparticles. Optimized nanoparticles were evaluated further with the help of scintigraphy imaging, which ascertains the uptake of drug into the brain. Based on maximum concentration, time-to-maximum concentration, area-under-curve over 24 hours, and elimination rate constant, intranasal TQ-loaded nanoparticles (TQ-NP1) proved more effective in brain targeting compared to intravenous and intranasal TQ solution. The high drug-targeting potential and efficiency demonstrates the significant role of the mucoadhesive properties of TQ-NP1. PMID:23180965

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

2012-01-01

51

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

PubMed Central

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

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

2015-01-01

52

Enhanced drug-loading and therapeutic efficacy of hydrotropic oligomer-conjugated glycol chitosan nanoparticles for tumor-targeted paclitaxel delivery.  

PubMed

Enhanced drug-loading and therapeutic efficacies are highly essential properties for nanoparticles as tumor-targeting drug carriers. Herein, we developed the glycol chitosan nanoparticles with hydrotropic oligomers (HO-CNPs) as a new tumor targeting drug delivery system. For enhancing drug-loading efficiency of paclitaxel in drug carriers, hydrotropic 2-(4-(vinylbenzyloxy)-N,N-diethylnicotinamide) (VBODENA-COOH) oligomers, that were used for enhancing the aqueous solubility of paclitaxel, were directly conjugated to glycol chitosan polymers. The amphiphilic conjugates readily formed nanoparticle structure (average size=302 ± 22 nm) in aqueous condition. Water-insoluble paclitaxel (PTX) was readily encapsulated into HO-CNPs with a high drug-loading amount up to 24.2 wt.% (2.4 fold higher than other polymeric nanoparticles) by a simple dialysis method. The PTX encapsulated HO-CNPs (PTX-HO-CNPs; average size=343 ± 12 nm) were very stable in aqueous media up to 50 days. Also, PTX-HO-CNPs presented rapid cellular uptake and lower cytotoxicity in cell culture system, compared to Cremophor EL/ethanol formulation of PTX. In tumor-bearing mice, the extravasation and accumulation of PTX-HO-CNPs in tumor tissue were precisely observed by intravital fluorescence imaging techniques. Furthermore, PTX-HO-CNPs showed the higher therapeutic efficacy, compared to Abraxane®, a commercialized PTX-formulation. These overall results demonstrate its potential as a new nano-sized PTX carrier for cancer treatment. PMID:24035978

Koo, Heebeom; Min, Kyung Hyun; Lee, Sang Cheon; Park, Jae Hyung; Park, Kinam; Jeong, Seo Young; Choi, Kuiwon; Kwon, Ick Chan; Kim, Kwangmeyung

2013-12-28

53

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

54

Site specific/targeted delivery of gemcitabine through anisamide anchored chitosan/poly ethylene glycol nanoparticles: an improved understanding of lung cancer therapeutic intervention.  

PubMed

Gemcitabine (2', 2'-difluorodeoxycytidine) is a deoxycytidine analog with significant antitumor activity against variety of cancers including non-small cell lung cancer. However, rapid metabolism and shorter half-life of drug mandate higher dose and frequent dosing schedule which subsequently results into higher toxicity. Therefore, there is a need to design a vector which can reduce the burden of frequent dosing and higher toxicity associated with the use of gemcitabine. In this study, we investigated the possibility of improving the targeting potential by employing the surface modification on Chitosan/poly(ethylene glycol) (CTS/PEG) Nanoparticles. We demonstrate formulation and characterization of chitosan/poly(ethylene glycol)-anisamide (CTS/PEG-AA) and compared its efficiency with CTS/PEG and free gemcitabine. Our results reveal its sizeable compatibility, comparatively less organ toxicity and higher antitumor activity in vitro as well as in vivo. This wealth of information surfaces the potential of CTS/PEG-AA nanoparticles as a potent carrier for drug delivery. In brief, this novel carrier opens new avenues for drug delivery which better meets the needs of anticancer research. PMID:23041219

Garg, Neeraj K; Dwivedi, Priya; Campbell, Christopher; Tyagi, Rajeev K

2012-12-18

55

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

PubMed Central

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

2014-01-01

56

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

PubMed Central

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

Shrestha, Annie; Hamblin, Michael R.

2012-01-01

57

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

PubMed

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

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

2015-02-01

58

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

PubMed

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

Ofokansi, Kenneth Chibuzor; Kenechukwu, Franklin Chimaobi

2013-01-01

59

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

PubMed Central

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

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

2014-01-01

60

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

PubMed Central

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

Ofokansi, Kenneth Chibuzor; Kenechukwu, Franklin Chimaobi

2013-01-01

61

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

PubMed Central

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

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

2011-01-01

62

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 300 nm diameter and +22 mV 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

63

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

PubMed Central

Background A critical disadvantage for successful chemotherapy with paclitaxel (PTX) is its nontargeting nature to cancer cells. Folic acid has been employed as a targeting ligand of various anticancer agents to increase their cellular uptake within target cells since the folate receptor is overexpressed on the surface of such tumor cells. In this study, a novel biodegradable deoxycholic acid-O-carboxymethylated chitosan–folic acid conjugate (DOMC-FA) was used to form micelles for encapsulating the anticancer drug PTX. Methods and results The drug-loading efficiency, encapsulation efficiency, in vitro drug release and physicochemical properties of PTX-loaded micelles were investigated in detail. In vitro cell culture studies were carried out in MCF-7 cells, a human breast carcinoma cell line, with folate receptor overexpressed on its surface. An increased level of uptake of folate-conjugated micelles compared to plain micelles in MCF-7 cells was observed, and the enhanced uptake of folate-micelles mainly on account of the effective process of folate receptor-mediated endocytosis. The MTT assay, morphological changes, and apoptosis test implied that the folate-conjugated micelles enhanced the cell death by folate-mediated active internalization, and the cytotoxicity of the FA-micellar PTX (DOMC-FA/PTX) to cancer cells was much higher than micelles without folate (DOMC/PTX) or the commercially available injectable preparation of PTX (Taxol). Conclusion Results indicate that the PTX-loaded DOMC-FA micelle is a successful anticancertargeted drug-delivery system for effective cancer chemotherapy. PMID:22287842

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

2012-01-01

64

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

PubMed Central

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

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

2014-01-01

65

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

Microsoft Academic Search

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

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

2009-01-01

66

Pegylation effect of chitosan based polyplex on DNA transfection.  

PubMed

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

Lin, Wen Jen; Hsu, Wan Yi

2015-04-20

67

Chitosan/siRNA nanoparticle targeting demonstrates a requirement for single-minded during larval and pupal olfactory system development of the vector mosquito Aedes aegypti  

PubMed Central

Background Essentially nothing is known about the genetic regulation of olfactory system development in vector mosquitoes, which use olfactory cues to detect blood meal hosts. Studies in Drosophila melanogaster have identified a regulatory matrix of transcription factors that controls pupal/adult odorant receptor (OR) gene expression in olfactory receptor neurons (ORNs). However, it is unclear if transcription factors that function in the D. melanogaster regulatory matrix are required for OR expression in mosquitoes. Furthermore, the regulation of OR expression during development of the larval olfactory system, which is far less complex than that of pupae/adults, is not well understood in any insect, including D. melanogaster. Here, we examine the regulation of OR expression in the developing larval olfactory system of Aedes aegypti, the dengue vector mosquito. Results A. aegypti bears orthologs of eight transcription factors that regulate OR expression in D. melanogaster pupae/adults. These transcription factors are expressed in A. aegypti larval antennal sensory neurons, and consensus binding sites for these transcription factors reside in the 5’ flanking regions of A. aegypti OR genes. Consensus binding sites for Single-minded (Sim) are located adjacent to over half the A. aegypti OR genes, suggesting that this transcription factor functions as a major regulator of mosquito OR expression. To functionally test this hypothesis, chitosan/siRNA nanoparticles were used to target sim during larval olfactory development. These experiments demonstrated that Sim positively regulates expression of a large subset of OR genes, including orco, the obligate co-receptor in the assembly and function of heteromeric OR/Orco complexes. Decreased innervation of the antennal lobe was also noted in sim knockdown larvae. These OR expression and antennal lobe defects correlated with a larval odorant tracking behavioral defect. OR expression and antennal lobe defects were also observed in sim knockdown pupae. Conclusions The results of this investigation indicate that Sim has multiple functions during larval and pupal olfactory system development in A. aegypti. PMID:24552425

2014-01-01

68

Chitosan Microspheres in Novel Drug Delivery Systems  

PubMed Central

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

Mitra, Analava; Dey, Baishakhi

2011-01-01

69

Chitosan against cutaneous pathogens  

PubMed Central

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

2013-01-01

70

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

71

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

72

Biomedical applications of carboxymethyl chitosans.  

PubMed

This review outlines the recent developments on carboxymethyl chitosan-based bio-medical applications. Carboxymethyl chitosan, a water soluble derivative of chitosan, with enhanced biological and physicochemical properties compared to chitosan, has emerged as a promising candidate for different biomedical applications. Introducing small chemical groups like carboxymethyl to the chitosan structure can drastically increase the solubility of chitosan at neutral and alkaline pH values without affecting their characteristic properties. Due to improved biocompatibility, high moisture retention ability more viscosity and enhanced antimicrobial property of carboxymethyl chitosan than chitosan makes it promising candidate for hydrogels and wound healing applications. The biodegradability and biocompatibility of carboxymethyl chitosan has significant interest with application as biomaterial for tissue engineering. Apart from this, the easy of carboxymethyl chitosan can be easily processed into nanoparticles so it has shown promise for drug delivery, bioimaging, biosensors and gene therapy applications. The contribution of carboxymethyl chitosan to green chemistry in the recent years has also been given in detail. This review will focus on preparative methods and physicochemical and biological properties of carboxymethyl chitosan with particular emphasis on biomedical and pharmaceutical applications of this derivative of chitosan. PMID:23044156

Upadhyaya, Laxmi; Singh, Jay; Agarwal, Vishnu; Tewari, Ravi Prakash

2013-01-01

73

Synthesis and ultraviolet visible spectroscopy studies of chitosan capped gold nanoparticles and their reactions with analytes.  

PubMed

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

Mohd Sultan, Norfazila; Johan, Mohd Rafie

2014-01-01

74

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

PubMed Central

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

Mohd Sultan, Norfazila

2014-01-01

75

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

76

Physical properties of fungal chitosan  

Microsoft Academic Search

Fungi are promising alternative sources of chitosan. This study evaluated the physical properties of fungal chitosan from\\u000a Absidia coerulea (AF 93105), Mucor rouxii (Ag 92033), and Rhizopus oryzae (Ag 92033). FT-IR and X-ray diffraction of the extracted products showed typical chitosan peak distributions which confirmed\\u000a the extracted products to be chitosan. All of their glucosamine contents and degrees of deacetylation

Wei-Ping Wang; Yu-Min Du; Xiao-Ying Wang

2008-01-01

77

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

78

Efficient siRNA delivery and tumor accumulation mediated by ionically cross-linked folic acid-poly(ethylene glycol)-chitosan oligosaccharide lactate nanoparticles: for the potential targeted ovarian cancer gene therapy.  

PubMed

For effective ovarian cancer gene therapy, systemic administrated tumor-targeting siRNA/folic acid-poly(ethylene glycol)-chitosan oligosaccharide lactate (FA-PEG-COL) nanoparticles is vital for delivery to cancer site(s). siRNA/FA-PEG-COL nanoparticles were prepared by ionic gelation for effective FA receptor-expressing ovarian cancer cells transfection and in vivo accumulation. The chemical structure of FA-PEG-COL conjugate was characterized by MALDI-TOF-MS, FT-IR and (1)H NMR. The average size of siRNA/FA-PEG-COL nanoparticles was approximately 200 nm, and the surface charge was +8.4 mV compared to +30.5 mV with siRNA/COL nanoparticles. FA-PEG-COL nanoparticles demonstrated superior compatibility with erythrocytes in terms of degree of aggregation and haemolytic activity and also effects on cell viability was lower when compared with COL nanoparticles. FA grafting significantly facilitated the uptake of nanoparticles via receptor mediated endocytosis as demonstrated by flow cytometry. The in vitro transfection and gene knockdown efficiency of HIF-1? were superior to COL nanoparticles (76-62%, respectively) and was comparable to Lipofectamine 2000 (79%) as demonstrated by RT-qPCR and Western blot. Gene knockdown at the molecular level translated into effective inhibition of proliferation in vitro. Accumulation efficiency of FA-PEG-COL nanoparticles was investigated in BALB/c mice bearing OVK18 #2 tumor xenograft using in vivo imaging. The active targeting FA-PEG-COL nanoparticles showed significantly greater accumulation than the passive targeting COL nanoparticles. Based on the results obtained, siRNA/FA-PEG-COL nanoparticles show much potential for effective ovarian cancer treatment via gene therapy. PMID:24178005

Li, Tony Shing Chau; Yawata, Toshio; Honke, Koichi

2014-02-14

79

Carbohydrate-functionalized chitosan fiber for influenza virus capture.  

PubMed

The high transmissibility and genetic variability of the influenza virus have made the design of effective approaches to control the infection particularly challenging. The virus surface hemagglutinin (HA) protein is responsible for the viral attachment to the host cell surface via the binding with its glycoligands, such as sialyllactose (SL), and thereby is an attractive target for antiviral designs. Herein we present the facile construction and development of two SL-incorporated chitosan-based materials, either as a water-soluble polymer or as a functional fiber, to demonstrate their abilities for viral adhesion inhibition and decontamination. The syntheses were accomplished by grafting a lactoside bearing an aldehyde-functionalized aglycone to the amino groups of chitosan or chitosan fiber followed by the enzymatic sialylation with sialyltransferase. The obtained water-soluble SL-chitosan conjugate bound HA with high affinity and inhibited effectively the viral attachment to host erythrocytes. Moreover, the SL-functionalized chitosan fiber efficiently removed the virus from an aqueous medium. The results collectively demonstrate that these potential new materials may function as the virus adsorbents for prevention and control of influenza. Importantly, these materials represent an appealing approach for presenting a protein ligand on a chitosan backbone, which is a versatile molecular platform for biofunctionalization and, thereby, can be used for not only antiviral designs, but also extensive medical development such as diagnosis and drug delivery. PMID:21978096

Li, Xuebing; Wu, Peixing; Gao, George F; Cheng, Shuihong

2011-11-14

80

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. PMID:20479963

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

2010-01-01

81

Chitosan hollow fiber membranes.  

PubMed

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

Modrzejewska, Zofia; Eckstein, Wojciech

2004-01-01

82

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

Microsoft Academic Search

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

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

2012-01-01

83

Antimicrobial action of exogenous chitosan.  

PubMed

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

Cuero, R G

1999-01-01

84

Thermophysical properties of chitosan, chitosan–starch and chitosan–pullulan films near the glass transition  

Microsoft Academic Search

The thermo-mechanical properties of aqueous solution-casted films of chitosan (C), starch–chitosan (SC) and pullulan–chitosan (PC) blends were examined by Dynamic Mechanical Thermal Analysis (DMTA) and large deformation tensile testing. Incorporation of sorbitol (10 and 30% d.b.) and\\/or adsoprtion of moisture by the films resulted in substantial depression of the glass transition (Tg) of the polysaccharide matrix due to plasticization. For

Athina Lazaridou; Costas G. Biliaderis

2002-01-01

85

Chemically modified chitin and chitosan as biomaterials  

Microsoft Academic Search

Recent studies of the chemical modification of chitin and chitosan are discussed from the viewpoint of biomedical applications. Special emphasis is placed on the role of individual functional groups in applications of modified chitosan. The modifications discussed here include chitosan attached to sugars, dendrimers, cyclodextrins, crown ethers, and glass beads. Among these derivatives, sugar-modified chitosans are excellent candidates for drug

Hitoshi Sashiwa; Sei-ichi Aiba

2004-01-01

86

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

87

C3, C5, and factor B bind to chitosan without complement C. Marchand,1,2  

E-print Network

with cationic chitosan par- ticles. Zymosan, a yeast ghost particle, activated comple- ment in serum. Complement activation is marked by the formation of a C3 convertase complex on the surface of target cells

Buschmann, Michael

88

Positive charge of chitosan retards blood coagulation on chitosan films.  

PubMed

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

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

2013-05-01

89

Antibacterial activity of chitosans and chitosan oligomers with different molecular weights  

Microsoft Academic Search

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

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

2002-01-01

90

Buoyant sustained release granules based on chitosan.  

PubMed

Attempts to develop sustained release intragastric 'floating' granules based on chitosan are described, using chitosan of different degrees of deacetylation (chitosan H and L), in granular form or in laminated preparations. The granules were made from chitosan H (chitosan H granules), from a 1:1 mixture of chitosan H and L (1:1 mixture granules), from a 1:2 mixture of chitosan H and L (1:2 mixture granules), or from chitosan L (chitosan L granules). They were prepared by a method involving deacidification, had internal cavities, were immediately buoyant in both acidic and neutral fluids, and gave sustained release of prednisolone (used as a model drug). The laminated preparations, composed of a chitosan granule layer and a chitosan L membrane, were also immediately buoyant in the same fluids, and also provided sustained release of the model drug. The release properties were controlled by regulating the chitosan L content of the granules, or the chitosan L membrane thickness of the laminate. In an absorption study using beagle dogs, sustained drug absorption from these preparations was obtained. PMID:2775446

Inouye, K; Machida, Y; Sannan, T; Nagai, T

1989-01-01

91

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

PubMed

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

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

2015-05-01

92

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

PubMed Central

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

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

2014-01-01

93

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

PubMed

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

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

2014-02-15

94

Modified chitosan carrying phosphonic and alkyl groups  

Microsoft Academic Search

The introduction of an alkyl chain onto a water soluble modified chitosan (N-methylene phosphonic chitosan) offer the presence of hydrophobic and hydrophilic branched for controlling solubility properties. A simple methodology for the preparation of a new chitosan derivative surfactant, N-lauryl-N-methylene phosphonic chitosan, has been developed. Its chemical identity was determined by FTIR and confirmed by 1H and 13C NMR. The

V. M. Ramos; N. M. Rodr??guez; M. S. Rodr??guez; A. Heras; E. Agulló

2003-01-01

95

Versatile carboxymethyl chitin and chitosan nanomaterials: a review.  

PubMed

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

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

2014-01-01

96

Optimization of microalgae coagulation process using chitosan  

Microsoft Academic Search

Here, we report on the harvesting of microalgae cells by coagulation using chitosan and the optimization of this process. Chitosan is a natural and environmentally friendly biopolymer created by the extensive deacetylation of chitin from shrimp, crab and crawfish. Although conventional chemical coagulants such as alum may have negative impacts on human health, the use of chitosan as coagulant is

A. L. Ahmad; N. H. Mat Yasin; C. J. C. Derek; J. K. Lim

2011-01-01

97

Porous chitosan scaffolds for tissue engineering  

Microsoft Academic Search

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

Sundararajan V. Madihally; Howard W. T. Matthew

1999-01-01

98

The chitosan yield of zygomycetes at their optimum harvesting time  

Microsoft Academic Search

Fungi are a promising alternative source of chitosan. Fungi can be manipulated to give chitosan of more consistent and desired physico-chemical properties compared to chitosan obtained from crustacean sources. Chitosan was extracted from the mycelia of Rhizopus oryzae USDB 0602 at various phases of growth. The growth phase which produced the most extractable chitosan was determined to be the late

Su Ching Tan; Teck Koon Tan; Sek Man Wong; Eugene Khor

1996-01-01

99

Development of a chitosan-based nanoparticle formulation for delivery of a hydrophilic hexapeptide, dalargin.  

PubMed

Nanoparticle based delivery systems can offer opportunities for targeting, controlled release, and enhanced stability of their drug, protein, or gene therapy payload. This study investigated the use of chitosan in combination with the ionic additives sulfobutyl-ether-7-beta-cyclodextrin (SB-CD) or SB-CD/dextran sulfate (SB-CD/DS) mixture in comparison with chitosan: DS in the formulation of nanoparticles incorporating the hexapeptide dalargin. The physical characteristics (particle size, zeta potential), entrapment and loading efficiency, and release of dalargin were quantified. It was demonstrated that anionic cyclodextrin, SB-CD, can be used in complex coacervation with chitosan, with and without the presence of DS, to form nanoparticles. The presence of SB-CD or DS in the nanoparticle formulation and the weight ratio of chitosan to anionic additive(s) influenced the physical properties of the nanoparticles and their ability to carry dalargin. In addition, the particle size of nanoparticles was also affected by the molecular weight of chitosan and DS. The use of either DS or SB-CD/DS mixture produced chitosan nanoparticles with small particle size, high dalargin entrapment efficiency, enhanced peptide stability, and sustained release characteristics. PMID:18655140

Chen, Yan; Siddalingappa, Basavaraj; Chan, Phoebe H H; Benson, Heather A E

2008-01-01

100

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

PubMed

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

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

2014-12-01

101

Environmental applications of chitosan and its derivatives.  

PubMed

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

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

2015-01-01

102

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

PubMed Central

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

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

2013-01-01

103

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

E-print Network

Chitosan modified with gadolinium diethylenetriaminepentaacetic acid for magnetic resonance imaging online 22 January 2010 Keywords: Chitosan DTPA Gadolinium Covalent bonding DNA pEGFPLuc Gene delivery STEM SEM ITC NMR a b s t r a c t We have prepared chitosan (CH)­gadolinium (Gd

Buschmann, Michael

104

Chitosan Modification and Pharmaceutical/Biomedical Applications  

PubMed Central

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

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

2010-01-01

105

Chitosan-based gastrointestinal delivery systems  

Microsoft Academic Search

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

Radi Hejazi; Mansoor Amiji

2003-01-01

106

Xylan chitosan conjugate - A potential food preservative  

Microsoft Academic Search

Xylan, a hemicellulose extracted from corn cobs, was co-heated with chitosan to prepare a polysaccharide-based food preservative. UV absorbance, browning and fluorescence changes indicated the presence of Maillard reaction between the two reactants. Antioxidant capacities, including 2,2-diphenyl-1-picrylhydrazyl (DPPH·) radical-scavenging activity and reducing power, showed that the xylan-chitosan conjugates possessed excellent antioxidant activity depending on the heating time while chitosan or

Xiaoxia Li; Xiaowen Shi; Miao Wang; Yumin Du

2011-01-01

107

Megalin-mediated specific uptake of chitosan/siRNA nanoparticles in mouse kidney proximal tubule epithelial cells enables AQP1 gene silencing.  

PubMed

RNAi-based strategies provide a great therapeutic potential for treatment of various human diseases including kidney disorders, but face the challenge of in vivo delivery and specific targeting. The chitosan delivery system has previously been shown to target siRNA specifically to the kidneys in mice when administered intravenously. Here we confirm by 2D and 3D bioimaging that chitosan formulated siRNA is retained in the kidney for more than 48 hours where it accumulates in proximal tubule epithelial cells (PTECs), a process that was strongly dependent on the molecular weight of chitosan. Chitosan/siRNA nanoparticles, administered to chimeric mice with conditional knockout of the megalin gene, distributed almost exclusively in cells that expressed megalin, implying that the chitosan/siRNA particle uptake was mediated by a megalin-dependent endocytotic pathway. Knockdown of the water channel aquaporin 1 (AQP1) by up to 50% in PTECs was achieved utilizing the systemic i.v. delivery of chitosan/AQP1 siRNA in mice. In conclusion, specific targeting PTECs with the chitosan nanoparticle system may prove to be a useful strategy for knockdown of specific genes in PTECs, and provides a potential therapeutic strategy for treating various kidney diseases. PMID:25157280

Gao, Shan; Hein, San; Dagnæs-Hansen, Frederik; Weyer, Kathrin; Yang, Chuanxu; Nielsen, Rikke; Christensen, Erik I; Fenton, Robert A; Kjems, Jørgen

2014-01-01

108

Megalin-Mediated Specific Uptake of Chitosan/siRNA Nanoparticles in Mouse Kidney Proximal Tubule Epithelial Cells Enables AQP1 Gene Silencing  

PubMed Central

RNAi-based strategies provide a great therapeutic potential for treatment of various human diseases including kidney disorders, but face the challenge of in vivo delivery and specific targeting. The chitosan delivery system has previously been shown to target siRNA specifically to the kidneys in mice when administered intravenously. Here we confirm by 2D and 3D bioimaging that chitosan formulated siRNA is retained in the kidney for more than 48 hours where it accumulates in proximal tubule epithelial cells (PTECs), a process that was strongly dependent on the molecular weight of chitosan. Chitosan/siRNA nanoparticles, administered to chimeric mice with conditional knockout of the megalin gene, distributed almost exclusively in cells that expressed megalin, implying that the chitosan/siRNA particle uptake was mediated by a megalin-dependent endocytotic pathway. Knockdown of the water channel aquaporin 1 (AQP1) by up to 50% in PTECs was achieved utilizing the systemic i.v. delivery of chitosan/AQP1 siRNA in mice. In conclusion, specific targeting PTECs with the chitosan nanoparticle system may prove to be a useful strategy for knockdown of specific genes in PTECs, and provides a potential therapeutic strategy for treating various kidney diseases. PMID:25157280

Gao, Shan; Hein, San; Dagnæs-Hansen, Frederik; Weyer, Kathrin; Yang, Chuanxu; Nielsen, Rikke; Christensen, Erik I; Fenton, Robert A; Kjems, Jørgen

2014-01-01

109

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

PubMed

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

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

2014-01-01

110

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. PMID:24959076

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

2014-01-01

111

Perspectives on: Chitosan Drug Delivery Systems Based on their Geometries  

Microsoft Academic Search

Chitosan is a natural polymer that has many physicochemical (polycationic, reactive OH and NH2 groups) and biological (bioactive, biocompatible, biodegradable) properties. These unique properties make chitosan an excellent material for the development of new biomedical applications. One of the most well known biomedical chitosan applications is in drug delivery systems. Chitosans have been used in the design of many different

Emir Baki Denkbas; Raphael M. Ottenbrite

2006-01-01

112

Chitosan nanoparticles as a novel delivery system for ammonium glycyrrhizinate  

Microsoft Academic Search

The ammonium glycyrrhizinate-loaded chitosan nanoparticles were prepared by ionic gelation of chitosan with tripolyphos- phate anions (TPP). The particle size and zeta potential of nanoparticles were determined, respectively, by dynamic light scattering (DLS) and a zeta potential analyzer. The effects, including chitosan molecular weight, chitosan concentration, ammonium gly- cyrrhizinate concentration and polyethylene glycol (PEG) on the physicochemical properties of the

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

2005-01-01

113

Chitosan/halloysite nanotubes bionanocomposites: structure, mechanical properties and biocompatibility.  

PubMed

Incorporation of nanosized reinforcements into chitosan usually results in improved properties and changed microstructures. Naturally occurred halloysite nanotubes (HNTs) are incorporated into chitosan for forming bionanocomposite films via solution casting. The electrostatic attraction and hydrogen bonding interactions between HNTs and chitosan are confirmed. HNTs are uniformly dispersed in chitosan matrix. The tensile strength and Young's modulus of chitosan are enhanced by HNTs. The storage modulus and glass transition temperature of chitosan/HNTs films also increase significantly. Blending with HNTs induces changes in surface nanotopography and increase of roughness of chitosan films. In vitro fibroblasts response demonstrates that both chitosan and chitosan/HNTs nanocomposite films are cytocompatibility even when the loading of HNTs is 10%. In summary, these results provide insights into understanding of the structural relationships of chitosan/HNTs bionanocomposite films in potential applications, such as scaffold materials in tissue engineering. PMID:22743347

Liu, Mingxian; Zhang, Yun; Wu, Chongchao; Xiong, Sheng; Zhou, Changren

2012-11-01

114

Biocompatibility of chitosan-coated iron oxide nanoparticles with osteoblast cells  

PubMed Central

Background: Bone disorders (including osteoporosis, loosening of a prosthesis, and bone infections) are of great concern to the medical community and are difficult to cure. Therapies are available to treat such diseases, but all have drawbacks and are not specifically targeted to the site of disease. Chitosan is widely used in the biomedical community, including for orthopedic applications. The aim of the present study was to coat chitosan onto iron oxide nanoparticles and to determine its effect on the proliferation and differentiation of osteoblasts. Methods: Nanoparticles were characterized using transmission electron microscopy, dynamic light scattering, x-ray diffraction, zeta potential, and vibrating sample magnetometry. Uptake of nanoparticles by osteoblasts was studied by transmission electron microscopy and Prussian blue staining. Viability and proliferation of osteoblasts were measured in the presence of uncoated iron oxide magnetic nanoparticles or those coated with chitosan. Lactate dehydrogenase, alkaline phosphatase, total protein synthesis, and extracellular calcium deposition was studied in the presence of the nanoparticles. Results: Chitosan-coated iron oxide nanoparticles enhanced osteoblast proliferation, decreased cell membrane damage, and promoted cell differentiation, as indicated by an increase in alkaline phosphatase and extracellular calcium deposition. Chitosan-coated iron oxide nanoparticles showed good compatibility with osteoblasts. Conclusion: Further research is necessary to optimize magnetic nanoparticles for the treatment of bone disease. PMID:23118539

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

2012-01-01

115

Chitin-chitosan: Properties, benefits and risks  

Microsoft Academic Search

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

S. S. Koide

1998-01-01

116

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

117

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

118

Chitosan for Improving Orchid Production and Quality  

Microsoft Academic Search

Chitosan is a deacetylated derivative of chitin that is derived from the cell walls of fungi, crustacean exoskeletons, cuticles of insects and some algae. It is considered environmental friendly for agricultural uses as it is easily degradable and non toxic to humans. Chitosan and its derivatives have been reported to elicit natural defence responses in plants and it has been

Apiradee Uthairatanakij

2007-01-01

119

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. PMID:23833516

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

2013-01-01

120

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

121

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. PMID:23355068

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

2013-01-01

122

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. PMID:24932114

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

2013-01-01

123

Galactosylated chitosan\\/DNA nanoparticles prepared using water-soluble chitosan as a gene carrier  

Microsoft Academic Search

Water-soluble chitosan (WSC) was used to increase the stability of chitosan in water and decrease the cytotoxicity induced by acetic acid. Lactobionic acid (LA) bearing galactose group was coupled with WSC for hepatocytes specificity. The composition of galactose in galactosylated chitosan (GC) was determined by NMR spectroscopy. The GC was complexed with plasmid DNA in various GC\\/DNA (N\\/P) charge ratios

Tae Hee Kim; In Kyu Park; Jae Woon Nah; Yun Jaie Choi; Chong Su Cho

2004-01-01

124

Probing cellular behaviors through nanopatterned chitosan membranes  

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

125

Green synthesis approach: extraction of chitosan from fungus mycelia.  

PubMed

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

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

2013-12-01

126

Synthesis of aligned hematite nanoparticles on chitosan-alginate films.  

PubMed

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

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

2009-07-01

127

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

128

Engineering Tenofovir Loaded Chitosan Nanoparticles  

PubMed Central

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

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

2011-01-01

129

Effects of carboxymethyl chitosan on the blood system of rats  

SciTech Connect

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

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

2011-04-29

130

Chitosan bicomponent nanofibers and nanoporous fibers  

Microsoft Academic Search

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

Lei Li; You-Lo Hsieh

2006-01-01

131

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

132

Chitosan bicomponent nanofibers and nanoporous fibers.  

PubMed

Nanofibers with average diameters between 20 and 100nm have been prepared by electrospinning of 82.5% deacetylated chitosan (Mv=1600 kDa) mixed with poly(vinyl alcohol) (PVA, Mw=124-186 kDa) in 2% (v/v) aqueous acetic acid. The formation of bicomponent fibers was feasible with 3% concentration of solution containing up to an equal mass of chitosan. Finer fibers, fewer beaded structures and more efficient fiber formation were observed with increasing PVA contents. Nanoporous fibers could be generated by removing the PVA component in the 17/83 chitosan/PVA bicomponent fibers with 1M NaOH (12 h). Fiber formation efficiency and composition uniformity improved significantly when the molecular weight of chitosan was halved by alkaline hydrolysis (50 wt% aqueous NaOH, 95 degrees C, 48 h). The improved uniform distribution of chitosan and PVA in the bicomponent fibers was attributed to better mixing mostly due to the reduced molecular weight and to the increased deacetylation of the chitosan. PMID:16376868

Li, Lei; Hsieh, You-Lo

2006-02-27

133

Physicochemical characterisation of ?-chitosan from Sepioteuthis lessoniana gladius.  

PubMed

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

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

2013-11-15

134

Nucleic acid delivery with chitosan and its derivatives.  

PubMed

Chitosan is a naturally occurring cationic mucopolysaccharide. It is generally biocompatible, biodegradable, mucoadhesive, non-immunogenic and non-toxic. Although chitosan is able to condense nucleic acids (NA) (both DNA and RNA) and protect them from nuclease degradation, its poor water solubility and low transfection efficacy have impeded its use as an NA carrier. In order to overcome such limitations, a multitude of strategies for chitosan modification and formulation have been proposed. In this article, we will first give a brief overview of the physical and biological properties of chitosan. Then, with a special focus on plasmid DNA delivery, we will have a detailed discussion of the latest advances in chitosan-mediated NA transfer. For future research, the following three important areas will be discussed: chitosan-mediated therapeutic small RNA transfer, structure-activity relationships (SAR) in chitosan vector design, and chitosan-mediated oral/nasal NA therapy. PMID:19100795

Lai, Wing-Fu; Lin, Marie Chia-Mi

2009-03-19

135

Plasticized chitosan/polyolefin films produced by extrusion.  

PubMed

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

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

2015-03-01

136

Adsorption of Chromium(VI) on Chitosan?Coated Perlite  

Microsoft Academic Search

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

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

2003-01-01

137

Chitosan as a lipid binder: a langmuir monolayer study of chitosan-lipid interactions.  

PubMed

Owing to its distinct chemico-biological properties, chitosan, a cationic biopolymer, offers a great potential in multifarious bioapplications. One such application is as a dietary antilipidemic supplement to be used to reduce obesity/overweight and to lower cholesterol. The lipid-binding efficiency of chitosan, however, remains debatable. Accordingly, in this study we investigated the interactions of chitosan with selected lipids, cholesterol and fatty acids, the latter including saturated (stearic acid) and unsaturated (oleic, linoleic, alpha-linolenic) acids. The experiments were performed with the Langmuir monolayer technique, in which surface pressure-area isotherms were recorded for the lipid monolayers spread on the acetate buffer pH 4.0 subphase in the absence and presence of chitosan. We found that the presence of chitosan in the subphase strongly influenced the shape and location of the isotherms, proving that there existed attractions between chitosan and lipid molecules. The attractions were revealed by changes of the molecular organization of the monolayers. The common feature of these changes was that all the monolayers studied underwent expansion, in each case reaching saturation with increasing chitosan concentration. In agreement with the lipid molecular structures, the highest expansions were observed for the most unsaturated fatty acids, linoleic and alpha-linolenic, the lowest for stearic acid, with oleic acid and cholesterol being the intermediate cases. By contrast, the main distinguishing feature of these changes was that, although none of the monolayers studied changed its state when completely saturated with chitosan, compared to the parent ones the compactness of the monolayers was modified. The solid monolayers of stearic acid and cholesterol were loosened, whereas those of all the unsaturated acids, liquid in nature, were tightened. On the basis of these results we tentatively propose a mechanism of the chitosan action that includes both electrostatic and hydrophobic lipid-chitosan interactions as well as hydrogen bonding between them. PMID:17630796

Wydro, Pawe?; Krajewska, Barbara; Hac-Wydro, Katarzyna

2007-08-01

138

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

139

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

140

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

141

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

142

Chitosan coated cotton fiber: preparation and physical properties  

Microsoft Academic Search

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

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

2001-01-01

143

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

144

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

PubMed

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

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

2015-01-01

145

Bioconjugation of quantum-dots with chitosan and N,N,N-trimethyl chitosan.  

PubMed

Novel carbohydrate-based hybrids combining chitosan and chemically modified chitosan with CdS inorganic nanoparticles were designed and prepared via aqueous route at room temperature. N,N,N-trimethylchitosan (TM-chitosan) was synthesized aiming at substantially improving the water solubility of chitosan for producing stable colloidal systems. UV-vis spectroscopy, photoluminescence spectroscopy, Nuclear magnetic resonance spectroscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy were used to characterize the synthesis and the relative stability of biopolymer-capped CdS nanocrystals. The results have clearly indicated that chitosan and chitosan-derivative (TM-chitosan) were remarkably effective on nucleating and stabilizing CdS nanoparticles in aqueous suspensions. In addition, the CdS nanocrystals were produced in the so-called "quantum-size confinement regime", with the calculated average size below 3.5 nm and fluorescent activity in the visible range of the spectra. Therefore, a new single-step process was developed for the bioconjugation of quantum dots with water soluble chemically functionalized carbohydrates at room temperature for potential biomedical applications. PMID:24751029

Mansur, Herman S; Mansur, Alexandra A P; Curti, Elisabete; De Almeida, Mauro V

2012-09-01

146

Isolation and characterization of chitin and chitosan from marine origin.  

PubMed

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

Nwe, Nitar; Furuike, Tetsuya; Tamura, Hiroshi

2014-01-01

147

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

PubMed Central

Engineered bone substitutes are being extensively explored in response to growing demand. However, the angiogenesis that occurs during bone formation is often overlooked in scaffold design. In this novel study, we incorporated two small interfering RNAs (siRNAs), ie, small interfering RNA targets casein kinase 2 interaction protein 1 (siCkip-1) and small interfering RNA targets soluble VEGF receptor 1 (siFlt-1), which can promote osteogenesis and angiogenesis, into a chitosan sponge. This scaffold could maintain siRNAs for over 2 weeks in neutral phosphate-buffered saline and degraded rapidly in the presence of lysozyme. The chitosan sponge with siCkip-1 and siFlt-1 in vitro bioactivity was investigated using mesenchymal stem cells. Target genes were significantly suppressed, and osteocalcin, alkaline phosphatase, and vascular endothelial growth factor were significantly upregulated. Alizarin Red staining revealed that mineralization of the extracellular matrix was markedly enhanced by dual transfection. Further analysis by immunofluorescence confirmed that the siRNA-modified scaffold simultaneously improved the expression of osteocalcin and von Willebrand factor. In vivo testing in a skull critical-size defect model showed marked bone regeneration in rats treated with siCkip-1 and siFlt-1. In conclusion, chitosan sponge containing osteogenic and angiogenic siRNAs may be used as a scaffold for bone regeneration. The dual siRNA concept may also be useful in the biofunctionalization of other materials. PMID:25429217

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

2014-01-01

148

Chitosan-silica hybrid porous membranes.  

PubMed

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

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

2014-09-01

149

Chitosan in Mucoadhesive Drug Delivery: Focus on Local Vaginal Therapy  

PubMed Central

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

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

2015-01-01

150

Strong adhesion and cohesion of chitosan in aqueous solutions  

PubMed Central

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

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

2014-01-01

151

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

152

Synergistic antimicrobial activities of natural essential oils with chitosan films.  

PubMed

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

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

2011-12-14

153

Biodegradation of chitosan and its effect on metal bioavailability.  

PubMed

The microbial breakdown of chitosan, a fishery waste-based material, and its derivative cross-linked chitosans, in both non-contaminated and contaminated conditions was investigated in a laboratory incubation study. Biodegradation of chitosan and cross-linked chitosans was affected by the presence of heavy metals. Zn was more pronounced in inhibiting microbial activity than Cu and Pb. It was estimated that a longer period is required to complete the breakdown of the cross-linked chitosans (up to approximately 100 years) than unmodified chitosan (up to approximately 10 years). The influence of biodegradation on the bioavailable fraction of heavy metals was studied concurrently with the biodegradation trial. It was found that the binding behaviour of chitosan for heavy metals was not affected by the biodegradation process. PMID:25263414

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

2015-02-01

154

Chitosan Fibers Modified with HAp/?–TCP Nanoparticles  

PubMed Central

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

Wawro, Dariusz; Pighinelli, Luciano

2011-01-01

155

Growth rate inhibition of phytopathogenic fungi by characterized chitosans  

PubMed Central

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

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

2012-01-01

156

Using nano-chitosan for harvesting microalga Nannochloropsis sp.  

PubMed

In this study, chitosan and nano-chitosan were used as flocculants agents for harvesting microalga Nannochloropsis sp. chitosan was modified to nano-chitosan by crosslinking with sodium tripolyphosphate. The effects of type and dosage of flocculants and the pH of the culture were investigated on biomass recovery. Optimum dosages for both bio-flocculants were found. The results showed that the dosage of flocculant consumption decreases by 40% and biomass recovery increases by 9% when nano-chitosan instead of chitosan is used as flocculant agent. Also, the recycled water from the harvesting process was reused which increases the growth of microalgae by about 7%. Finally, the cost analysis of harvesting process showed the feasibility of using nano-chitosan as flocculation agent. PMID:23415940

Farid, Mohammad Sadegh; Shariati, Ahmad; Badakhshan, Amir; Anvaripour, Bagher

2013-03-01

157

Feasibility of Photocrosslinkable Chitosan as an Embolization Material for Aneurysms  

PubMed Central

Summary The purpose of this study was to evaluate the feasibility of photocrosslinkable chitosan as an embolization material for aneurysms. Three experimental aneurysms were created in three Japanese white rabbits. All of the aneurysms were packed with chitosan hydrogel. Histopathologic data were analyzed on two, seven, and 30 days after embolization. Unorganized clots and minimal inflammation around the applied chitosan hydrogel were observed two days after implantation. After seven days, the chitosan was reduced and inflammatory response appeared. At 30 days, most of the aneurysm lumen was replaced with inflammatory cells, and the remaining chitosan was not observed. Severe complications such as anaphylaxis did not occur after the embolization with the chitosan. These results suggest that photocros-slinkable chitosan might be a candidate for an embolization material for endovascular treatment of cerebral aneurysms. PMID:20587256

Nakai, K.; Kojima, T.; Hattori, K.; Miyachi, S.; Ishihara, M.; Kobayashi, N.; Okamoto, T.; Yoshida, J.

2004-01-01

158

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

PubMed Central

Chitosan, a well known natural cationic polysaccharide, has been successfully implemented in vitro and in vivo as a nonviral delivery system for both plasmid DNA and siRNA. While using chitosan/siRNA polyplexes to knock down specific targets, we have underestimated the effect of nucleic acids binding to chitosan when extracting RNA for subsequent quantitative PCR evaluation of silencing. In vitro transfection using chitosan/siRNA-based polyplexes reveals a very poor recovery of total RNA especially when using low cell numbers in 96 well plates. Here, we describe a method that dramatically enhances RNA extraction from chitosan/siRNA-treated cells by using an enzymatic treatment with a type III chitosanase. We show that chitosanase treatment prior to RNA extraction greatly enhances the yield and the integrity of extracted RNA. This method will therefore eliminate the bias associated with lower RNA yield and integrity when quantifying gene silencing of chitosan-based systems using quantitative real time PCR. PMID:20957169

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

2010-01-01

159

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

160

Formulation and comparative characterization of chitosan, gelatin, and chitosan-gelatin-coated liposomes of CPT-11-HCl.  

PubMed

Liposomes containing phosphatidylcholine and cholesterol (uncoated) and coated by chitosan, gelatin, and combination of chitosan and gelatin were prepared by the modified ethanol injection method. The aim of this work was to formulate and characterize liposomes of camptothecin (CPT)-11-HCl (Irinotecan HCl) containing chitosan, gelatin, and both polymers as coating materials; and also to increase its circulation longevity when compared with the free drug while maintaining the agent in its active lactone form. Size, shape, zeta potential, encapsulation efficiency, stability study, in vitro, and in vivo release study were used for characterization of liposomes. The size of liposomes was in the order of uncoated < chitosan coated < gelatin coated < combination of chitosan and gelatin coated. The zeta potential of liposomes was in the order of combination of chitosan and gelatin coated > chitosan coated > gelatin coated > uncoated. The formulations showed the long-term stability. The encapsulation efficiency of liposomes was in order of combination of chitosan and gelatin coated > gelatin coated > chitosan coated > uncoated. The in vitro and in vivo release of drug was observed in the order of combination chitosan and gelatin coated > gelatin coated > chitosan coated > uncoated. PMID:18951273

Shende, Pravin; Gaud, Ram

2009-05-01

161

Solid polymer electrolyte from phosphorylated chitosan  

SciTech Connect

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

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

2014-03-24

162

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

Federal Register 2010, 2011, 2012, 2013, 2014

...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

163

Preparation of a novel chitosan derivative and use in water treatment  

Microsoft Academic Search

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

Min Zhang; ChengYu Tan; Liang Kong; LuChen Jin

2011-01-01

164

Effect of chitosan and its derivatives as antifungal and preservative agents on postharvest green asparagus.  

PubMed

The antifungal activity and effect of high-molecular weight chitosan (H-chitosan), low-molecular weight chitosan (L-chitosan) and carboxymethyl chitosan (C-chitosan) coatings on postharvest green asparagus were evaluated. L-chitosan and H-chitosan efficiently inhibited the radial growth of Fusarium concentricum separated from postharvest green asparagus at 4 mg/ml, which appeared to be more effective in inhibiting spore germination and germ tube elongation than that of C-chitosan. Notably, spore germination was totally inhibited by L-chitosan and H-chitosan at 0.05 mg/ml. Coated asparagus did not show any apparent sign of phytotoxicity and maintained good quality over 28 days of cold storage, according to the weight loss and general quality aspects. Present results inferred that chitosan could act as an attractive preservative agent for postharvest green asparagus owing to its antifungal activity and its ability to stimulate some defense responses during storage. PMID:24594161

Qiu, Miao; Wu, Chu; Ren, Gerui; Liang, Xinle; Wang, Xiangyang; Huang, Jianying

2014-07-15

165

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

PubMed Central

Background and the purpose of the study Carvedilol nonselective ?-adrenoreceptor blocker, chemically (±)-1-(Carbazol-4-yloxy)-3-[[2-(o-methoxypHenoxy) ethyl] amino]-2-propanol, slightly soluble in ethyl ether; and practically insoluble in water, gastric fluid (simulated, TS, pH 1.1), and intestinal fluid (simulated, TS without pancreatin, pH 7.5) Compounds with aqueous solubility less than 1%?W/V often represents dissolution rate limited absorption. There is need to enhance the dissolution rate of carvedilol. The objective of our present investigation was to compare chitosan and chitosan chlorhydrate based various approaches for enhancement of dissolution rate of carvedilol. Methods The different formulations were prepared by different methods like solvent change approach to prepare hydrosols, solvent evaporation technique to form solid dispersions and cogrind mixtures. The prepared formulations were characterized in terms of saturation solubility, drug content, infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), electron microscopy, in vitro dissolution studies and stability studies. Results The practical yield in case of hydrosols was ranged from 59.76 to 92.32%. The drug content was found to uniform among the different batches of hydrosols, cogrind mixture and solid dispersions ranged from 98.24 to 99.89%. There was significant improvement in dissolution rate of carvedilol with chitosan chlorhdyrate as compare to chitosan and explanation to this behavior was found in the differences in the wetting, solubilities and swelling capacity of the chitosan and chitosan salts, chitosan chlorhydrate rapidly wet and dissolve upon its incorporation into the dissolution medium, whereas the chitosan base, less water soluble, would take more time to dissolve. Conclusion This technique is scalable and valuable in manufacturing process in future for enhancement of dissolution of poorly water soluble drugs. PMID:23351907

2012-01-01

166

Interaction of chitosan with natural or synthetic anionic polyelectrolytes. 1. The chitosan–carboxymethylcellulose complex  

Microsoft Academic Search

Chitosan, the unique cationic groups-containing polysaccharide is a natural, renewable, nontoxic and biodegradable source being considered as ‘ecologically-friendly’ product. It has been studied as partner in several intermacromolecular complexes (IMC) with natural or synthetic anionic polyelectrolytes. The present investigation discusses some new results on the chitosan–carboxymethylcellulose interaction studied in solution by conductometric, potentiometric and turbidimetric titration, and in the solid

Carmen Rosca; Marcel Ionel Popa; Gabriela Lisa; Gabrielle Charlotte Chitanu

2005-01-01

167

Interaction of chitosan and mucin in a biomembrane model environment.  

PubMed

Chitosans have been widely exploited in biological applications, including drug delivery and tissue engineering, especially owing to their mucoadhesive properties, but the molecular-level mechanisms for the chitosan action are not known in detail. It is believed that chitosan could affect the mucus by interacting with the proteins mucins, in a process mediated by the cell membrane. In this study we used Langmuir monolayers of dimyristoylphosphatidic acid (DMPA) as simplified membrane models to investigate the interplay between the activity of mucins and chitosan. Surface pressure and surface potential measurements were performed with DMPA monolayers onto which chitosan and/or mucin was adsorbed. We found that the expanding effect from mucin was considerably reduced when chitosan was injected after mucin had been adsorbed on the DMPA monolayer. The results were consistent with the formation of complexes between mucin and chitosan, thus highlighting the importance of electrostatic interactions. Furthermore, chitosan could remove mucin that was co-deposited along with DMPA in Langmuir-Blodgett (LB) films, which could be ascribed to molecular-level interactions between chitosan and mucin inferred from the FTIR spectra of the LB films. In conclusion, the results with Langmuir and LB films suggest that electrostatic interactions are crucial for the mucoadhesive mechanism, which is affected by the complexation between chitosan and mucin. PMID:22469069

Silva, Cristiane A; Nobre, Thatyane M; Pavinatto, Felippe J; Oliveira, Osvaldo N

2012-06-15

168

New Insights into Chitosan-DNA Interactions Using Isothermal Titration Microcalorimetry  

E-print Network

New Insights into Chitosan-DNA Interactions Using Isothermal Titration Microcalorimetry Pei Lian Ma of deacetylation (DDA), and molecular weight (Mn) of chitosan, using isothermal titration microcalorimetry (ITC

Buschmann, Michael

169

Chemistry and application of chitin and chitosan  

Microsoft Academic Search

Organosoluble derivatives of chitin were prepared and used as precursors for regioselective and quantitative chemical modifications. Based on these precursors, various sugar groups could be introduced to prepare nonnatural branched chitins and chitosans. With a view to establishing a new route to facile modifications, reactivity of ?-chitin was examined and confirmed to be much higher than that of ordinary ?-chitin.

Keisuke Kurita

1998-01-01

170

Implantable applications of chitin and chitosan  

Microsoft Academic Search

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

Eugene Khor; Lee Yong Lim

2003-01-01

171

Chitosan-based nanocarriers for antimalarials  

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

172

Photochemical tissue bonding with chitosan adhesive films  

PubMed Central

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

2010-01-01

173

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

174

Effect of water-soluble P-chitosan and S-chitosan on human primary osteoblasts and giant cell tumor of bone stromal cells  

Microsoft Academic Search

Water-soluble phosphorylated chitosan (P-chitosan) and disodium (1 --> 4)-2-deoxy-2-sulfoamino-beta-D-glucopyranuronan (S-chitosan) are two chemically modified chitosans. In this study, we found that P-chitosan significantly promotes cell proliferation of both human primary osteoblasts (OBs) and the OB like stromal cell component of the giant cell tumor of bone (GCTB) cells at the concentration from 125 to 1000 µg ml-1 at all time

T. Tang; G. Zhang; Carol PY Lau; L. Z. Zheng; X. H. Xie; X. L. Wang; X. H. Wang; K. He; Y. Patrick; L. Qin; Shekhar M. Kumta

2011-01-01

175

Chitosan microspheres as a potential carrier for drugs.  

PubMed

Chitosan is a biodegradable natural polymer with great potential for pharmaceutical applications due to its biocompatibility, high charge density, non-toxicity and mucoadhesion. It has been shown that it not only improves the dissolution of poorly soluble drugs but also exerts a significant effect on fat metabolism in the body. Gel formation can be obtained by interactions of chitosans with low molecular counterions such as polyphosphates, sulphates and crosslinking with glutaraldehyde. This gelling property of chitosan allows a wide range of applications such as coating of pharmaceuticals and food products, gel entrapment of biochemicals, plant embryo, whole cells, microorganism and algae. This review is an insight into the exploitation of the various properties of chitosan to microencapsulate drugs. Various techniques used for preparing chitosan microspheres and evaluation of these microspheres have also been reviewed. This review also includes the factors that affect the entrapment efficiency and release kinetics of drugs from chitosan microspheres. PMID:15072779

Sinha, V R; Singla, A K; Wadhawan, S; Kaushik, R; Kumria, R; Bansal, K; Dhawan, S

2004-04-15

176

Glycerophosphate-based chitosan thermosensitive hydrogels and their biomedical applications.  

PubMed

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

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

2015-03-01

177

Chitosan-caseinate bilayer coatings for paper packaging materials.  

PubMed

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

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

2014-01-01

178

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

179

Effectiveness of chitosan against wine-related microorganisms.  

PubMed

The antimicrobial action of chitosan against wine related microorganisms, including Lactobacillus plantarum, Saccharomyces cerevisiae, Oeonococcus oeni, Lactobacillus hilgardii, Brettanomyces bruxellensis, Hanseniaspora uvarum and Zygosaccharomyces bailii was examined in laboratory media. In order to assess the potential applicability of chitosan as a microbial control agent for wine, the effect of chitosan, applied individually and/or in combination with sulphur dioxide (SO2), on the growth of microorganisms involved in various stages of winemaking and on the fermentative performance of S. cerevisiae was investigated. Of the seven wine-related microorganisms studied, S. cerevisiae exhibited the strongest resistance to antimicrobial action of chitosan in laboratory media with a minimum inhibitory concentration (MIC) greater than 2 g/L. L. hilgardii, O. oeni and B. bruxellensis were the most susceptible to chitosan since they were completely inactivated by chitosan at 0.2 g/L. The MIC of chitosan for L. plantarum, H. uvarum and Z. bailii was 2, 0.4 and 0.4 g/L, respectively. In wine experiments, it was found that chitosan had a retarding effect on alcoholic fermentation without significantly altering the viability and the fermentative performance of S. cerevisiae. With regard to non-Saccharomyces yeasts (H. uvarum and Z. bailii) involved in winemaking, the early deaths of these yeasts in mixed cultures with S. cerevisiae were not probably due to the antimicrobial action of chitosan but rather due to ethanol produced by the yeasts. The complex interactions between chitosan and wine ingredients as well as microbial interactions during wine fermentation considerably affect the efficacy of chitosan. It was concluded that chitosan was worthy of further investigation as an alternative or complementary preservative to SO2 in wine industry. PMID:25528342

Ba?der Elmac?, Simel; Gülgör, Gök?en; Tokatl?, Mehmet; Erten, Hüseyin; ??ci, Asl?; Özçelik, Filiz

2015-03-01

180

Characterization of PVA-Chitosan Nanofibers Prepared by Electrospinning  

Microsoft Academic Search

PVA\\/Chitosan nanocomposite fibers were prepared by electrospinning method. The weight ratio of PVA:Chitosan was fixed at 80:20 in 2% Acetic acid. The concentration of the PVA\\/Chitosan solution was varied from 3 to 5 wt%. The viscosity of precursor solution was determined by Ubbelohe viscometer. The results revealed that the mixture solution viscosity is directly proportional to its concentration. The morphology

K. Paipitak; T. Pornpra; P. Mongkontalang; W. Techitdheer; W. Pecharapa

2011-01-01

181

Surface states of PVA\\/chitosan blended hydrogels  

Microsoft Academic Search

Hydrogels were prepared from blends of poly(vinyl alcohol) (PVA) and chitosan in varying proportions. Electron spectroscopy analysis of the resulting hydrogel membranes, cast on glass plates, revealed that the chitosan component was concentrated on the surface of the air-surface side of the membranes and was nearly constant from 10 to 40wt% of chitosan content of the blends. The increasing water-contact

T Koyano; N Koshizaki; H Umehara; M Nagura; N Minoura

2000-01-01

182

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

183

Controlling chitosan-based encapsulation for protein and vaccine delivery.  

PubMed

Chitosan-based nano/microencapsulation is under increasing investigation for the delivery of drugs, biologics and vaccines. Despite widespread interest, the literature lacks a defined methodology to control chitosan particle size and drug/protein release kinetics. In this study, the effects of precipitation-coacervation formulation parameters on chitosan particle size, protein encapsulation efficiency and protein release were investigated. Chitosan particle sizes, which ranged from 300 nm to 3 ?m, were influenced by chitosan concentration, chitosan molecular weight and addition rate of precipitant salt. The composition of precipitant salt played a significant role in particle formation with upper Hofmeister series salts containing strongly hydrated anions yielding particles with a low polydispersity index (PDI) while weaker anions resulted in aggregated particles with high PDIs. Sonication power had minimal effect on mean particle size, however, it significantly reduced polydispersity. Protein loading efficiencies in chitosan nano/microparticles, which ranged from 14.3% to 99.2%, were inversely related to the hydration strength of precipitant salts, protein molecular weight and directly related to the concentration and molecular weight of chitosan. Protein release rates increased with particle size and were generally inversely related to protein molecular weight. This study demonstrates that chitosan nano/microparticles with high protein loading efficiencies can be engineered with well-defined sizes and controllable release kinetics through manipulation of specific formulation parameters. PMID:24560459

Koppolu, Bhanu Prasanth; Smith, Sean G; Ravindranathan, Sruthi; Jayanthi, Srinivas; Suresh Kumar, Thallapuranam K; Zaharoff, David A

2014-05-01

184

In situ chitosan gelation initiated by atmospheric plasma treatment.  

PubMed

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

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

2014-03-15

185

Applied Usage of Yeast Spores as Chitosan Beads  

PubMed Central

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 Cu2+, Cr3+, and Cd2+, 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

2014-01-01

186

Development of monetite/phosphorylated chitosan composite bone cement.  

PubMed

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

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

2014-02-01

187

Chitosan in nasal delivery systems for therapeutic drugs.  

PubMed

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

Casettari, Luca; Illum, Lisbeth

2014-09-28

188

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

Microsoft Academic Search

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

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

2002-01-01

189

Synergistic effect of poly(ethylenimine) on the transfection efficiency of galactosylated chitosan/DNA complexes.  

PubMed

The use of chitosan for gene delivery is limited due to the low transfection efficiency and difficulty in transfecting into a variety of cell types, especially the hepatoma cells. In order to solve this problem, lactobionic acid (LA) bearing galactose group was coupled with water-soluble chitosan (WSC) for liver specificity and poly(ethylenimine) (PEI) was combined to galactosylated chitosan (GC)/DNA complexes to enhance the transfection efficiency. For initial study, the effect of PEI on the transfection efficiency of WSC/DNA complex was studied in HeLa, A549 and 293 T cells, and bafilomycin A1 was used to ascertain the mechanism of synergistic effect. Transfection efficiency, cytotoxicity, and physicochemical properties of GC/DNA complex combined with PEI were investigated to determine the potential for the hepatocyte-targeting. The combination of PEI with WSC/DNA and GC/DNA complex dramatically increased the luciferase expression 10- to 1000-fold in various cell lines, and the synergistic effect was proved to be induced by proton sponge effect of PEI. The transfection of GC/DNA complex in HepG2 was much higher than that of WSC/DNA even after combination with PEI, and was highly inhibited in the presence of galactose. Cytotoxicity of PEI was much decreased by combination with GC/DNA complex. And PEI was proved to be coated on the surface of GC/DNA complex through the ionic interaction. PMID:15949861

Kim, Tae Hee; Kim, Su Il; Akaike, Toshihiro; Cho, Chong Su

2005-07-20

190

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

E-print Network

solutions of chitosan in a glycerol phosphate buffer (chitosan-GP) with physiological pH and osmolality wereUltrastructure of Hybrid Chitosan-Glycerol Phosphate Blood Clots by Environmental Scanning Electron that glycerol phosphate diffuses freely from chitosan-GP gels (by EDS of phosphorus) and that hyperosmotic

Buschmann, Michael

191

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

E-print Network

phosphate buffer (chitosan­GP) with phys- iological pH and osmolality were mixed with autologous bloodUltrastructure of Hybrid Chitosan­Glycerol Phosphate Blood Clots by Environmental Scanning Electron chitosan; chitosan­glycerol phosphate; biomaterials; blood; glutaraldehyde; paraformaldehyde; environmental

Buschmann, Michael

192

Monosaccharides and chitosan sensing in bud growth and petal pigmentation in Eustoma grandiflorum (Raf.) Shinn  

Microsoft Academic Search

This study focused on the application of chitosan and monosaccharide to lisianthus cultivars in vitro. Buds from three cultivars, ‘Asuka no Asa’, ‘Mickey Rose’, and ‘Royal Violet’, were kept in a holding solution containing different sugars, with or without chitosan. The cultivars showed distinct variations in flower bud development on treatment with chitosan. Following treatment with fructose and chitosan, a

A. F. M. Jamal Uddin; Fumio Hashimoto; Keiichi Shimizu; Yusuke Sakata

2004-01-01

193

Enhanced abilities of highly swollen chitosan beads for color removal and tyrosinase immobilization  

Microsoft Academic Search

The enhancement of abilities for the removal of reactive dyes and immobilization of tyrosinase onto highly swollen chitosan beads was demonstrated compared to the use of common chitosan flakes. Chitosan was prepared from natural cuttlebone wastes. It was shown that the adsorption capacity of dyes at 30°C using swollen chitosan beads was around five times greater than that using common

Feng-Chin Wu; Ru-Ling Tseng; Ruey-Shin Juang

2001-01-01

194

Food applications of chitin and chitosans  

Microsoft Academic Search

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

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

1999-01-01

195

Sorption of malachite green on chitosan bead  

Microsoft Academic Search

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

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

2008-01-01

196

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

197

Chitosan films and blends for packaging material.  

PubMed

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

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

2015-02-13

198

ECM-Chitosan Bandage for Tissue Repair  

NASA Astrophysics Data System (ADS)

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

Lauto, Antonio; Longo, Leonardo

2010-05-01

199

Nitric Oxide-Releasing Chitosan Oligosaccharides as Antibacterial Agents  

PubMed Central

Secondary amine-functionalized chitosan oligosaccharides of different molecular weights (i.e., ~2500, 5000, 10000) were synthesized by grafting 2-methyl aziridine from the primary amines on chitosan oligosaccharides, followed by reaction with nitric oxide (NO) gas under basic conditions to yield N-diazeniumdiolate NO donors. The total NO storage, maximum NO flux, and half-life of the resulting NO-releasing chitosan oligosaccharides were controlled by the molar ratio of 2-methyl aziridine to primary amines (e.g., 1:1, 2:1) and the functional group surrounding the N-diazeniumdiolates (e.g., polyethylene glycol (PEG) chains), respectively. The secondary amine-modified chitosan oligosaccharides greatly increased the NO payload over existing biodegradable macromolecular NO donors. In addition, the water-solubility of the chitosan oligosaccharides enabled their penetration across the extracellular polysaccharides matrix of Pseudomonas aeruginosa biofilms and association with embedded bacteria. The effectiveness of these chitosan oligosaccharides at biofilm eradication was shown to depend on both the molecular weight and ionic characteristics. Low molecular weight and cationic chitosan oligosaccharides exhibited rapid association with bacteria throughout the entire biofilm, leading to enhanced biofilm killing. At concentrations resulting in 5-log killing of bacteria in Pseudomonas aeruginosa biofilms, the NO-releasing and control chitosan oligosaccharides elicited no significant cytotoxicity to mouse fibroblast L929 cells in vitro. PMID:24268196

Lu, Yuan; Slomberg, Danielle L.; Schoenfisch, Mark H.

2014-01-01

200

Some biomedical applications of chitosan-based hybrid nanomaterials  

NASA Astrophysics Data System (ADS)

Being naturally abundant resources and having many interesting physicochemical and biological properties, chitin/chitosan have been found to be useful in many fields, especially biomedical ones. This paper describes the strategy to design multifunctional, hybrid chitosan-based nanomaterials and test them in some typical biomedical applications.

Tran, Dai Lam; Dien Pham, Gia; Phuc Nguyen, Xuan; Hoang Vu, Dinh; Thinh Nguyen, Ngoc; Hoang Tran, Vinh; Thu Trang Mai, Thi; Binh Nguyen, Hai; Duong Le, Quang; Ngoan Nguyen, Thi; Cham Ba, Thi

2011-12-01

201

Applications and Environmental Aspects of Chitin and Chitosan  

Microsoft Academic Search

A survey on the properties of the natural nitrogen-containing polysaccharides chitin and chitosan is given. Outstanding features are the materials' mechanical and chemical properties which offer numerous, largely unexplored applications in technology, chemistry, medicine, and agriculture. Derivatives of chitin and chitosan are accessible by reactions of the hydroxy and amino groups with appropriate reagents. Various types of gels, membranes, and

Martin G. Peter

1995-01-01

202

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

203

Cell response to Electrospun PVA and PVA\\/Chitosan nanofibers  

Microsoft Academic Search

PVA and chitosan have been used for many tissue engineering applications. However, most of the studies use only single polymer to fabricate nanofibers. Therefore, the purpose of this study is to fabricate PVA and PVA\\/Chitosan nanofiber scaffold for potential tissue engineering applications. The nanofrous scaffold was produced via electrospinning. NIH 3T3 fibroblast cells were seeded onto scaffolds for different time

J. I. Liang; H. C. Hsu; Y. H. Nien; F. C. Su; H. W. Wu; J. P. Chen; M. L. Yeh

2009-01-01

204

Physical properties and molecular behavior of chitosan films.  

PubMed

Chitosan films, varying in molecular weight and degree of deacetylation, were prepared by a casting technique using acetic acid as a dissolving vehicle. The physicochemical properties of the films were characterized. Both molecular weight and degree of deaceylation affected the film properties. Powder X-ray diffraction patterns and differential scanning calorimetry thermograms of all chitosan films indicated their amorphous state to partially crystalline state with thermal degradation temperature lower than 280-300 degrees C. The increase in molecular weight of chitosan would increase the tensile strength and elongation as well as moisture absorption of the films, whereas the increase in degree of deacetylation of chitosan would either increase or decrease the tensile strength of the films depending on its molecular weight. Moreover, the higher the degree of deacetylation of chitosan the more brittle and the less moisture absorption the films became. All chitosan films were soluble in HCl-KCl buffer (pH 1.2), normal saline, and distilled water. They swelled in phosphate buffer (pH 7.4), and cross-linking between chitosan and phosphate anions might occur Finally, transmission infrared and 13C-NMR spectra supported that chitosan films prepared by using acetic acid as a dissolving were chitosonium acetate films. PMID:11266226

Nunthanid, J; Puttipipatkhachorn, S; Yamamoto, K; Peck, G E

2001-02-01

205

Effects of steam sterilization on thermogelling chitosan-based gels.  

PubMed

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

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

2001-01-01

206

Antimicrobial and physicochemical properties of chitosan-HPMC-based films.  

PubMed

To prepare composite films from biopolymers with anti-listerial activity and moisture barrier properties, the antimicrobial efficiency of chitosan-hydroxy propyl methyl cellulose (HPMC) films, chitosan-HPMC films associated with lipid, and chitosan-HPMC films chemically modified by cross-linking were evaluated. In addition, the physicochemical properties of composite films were evaluated to determine their potential for food applications. The incorporation of stearic acid into the composite chitosan-HPMC film formulation decreased water sensitivity such as initial solubility in water and water drop angle. Thus, cross-linking of composite chitosan-HPMC, using citric acid as the cross-linking agent, led to a 40% reduction in solubility in water. The water vapor transfer rate of HPMC film, approximately 270 g x m(-2) x day(-1) x atm(-1), was improved by incorporating chitosan and was further reduced 40% by the addition of stearic acid and/or cross-linking. Anti-listerial activity of films was determined on solid medium by a numeration technique. Chitosan-HPMC-based films, with and without stearic acid, inhibited the growth of Listeria monocytogenes completely. On the other hand, a loss of antimicrobial activity after chemical cross-linking modification was observed. FTIR and 13C NMR analyses were then conducted in order to study a potential chemical modification of biopolymers such as a chemical reaction with the amino group of chitosan. To complete the study, the mechanical properties of composite films were determined from tensile strength assays. PMID:15479027

Möller, Heike; Grelier, Stéphane; Pardon, Patrick; Coma, Véronique

2004-10-20

207

Electrically Conductive Chitosan/Carbon Scaffolds for Cardiac Tissue Engineering  

PubMed Central

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

2015-01-01

208

Time-dependent effects of chitosan on dentin structures.  

PubMed

Complete debridement with smear layer removal are essential measures for achieving a successful outcome of root canal treatment. The aim of this study was to evaluate the effects of chitosan at different concentrations on the removal of the smear layer and on dentin structure after 3 and 5 min of application. Twelve recently extracted maxillary canine teeth were instrumented using the crown-down technique and irrigated with 1% sodium hypochlorite. The specimens were distributed according to the time and concentration of the final irrigating solution: G1: 0.1% chitosan for 3 min; G2: 0.2% chitosan for 3 min; G3: 0.37% chitosan for 3 min; G4: 0.1% chitosan for 5 min; G5: 0.2% chitosan for 5 min; G6: 0.37% chitosan for 5 min. All samples were prepared for SEM analysis. G1 exhibited removal of the smear layer, but not the smear plugs. G2 showed visible and open tubules with slight erosion of the peritubular dentin. Cleaning in G3 was similar to that in G2, however, the erosive effect was greater. There was expansion of the diameter of the tubules in G4; and in G5 and G6, there was severe erosion with deterioration of dentin surface. In conclusion, 0.2% chitosan for 3 min appeared to be efficient for removing the smear layer, causing little erosion of dentin. PMID:23207849

Silva, Polliana Vilaça; Guedes, Débora Fernandes Costa; Pécora, Jesus Djalma; da Cruz-Filho, Antonio Miranda

2012-01-01

209

Chitosan-calcium carbonate composites by a biomimetic process  

Microsoft Academic Search

The crystal growth of calcium carbonate on a chitosan substrate was achieved using a supersaturated calcium carbonate solution, by using various additives, such as 6-aminocaproic acid (6AA) and polyacrylic acid (PAA). Polyacrylic acid modified the chitosan-film surface and promoted the nucleation of calcium carbonate crystals. In the absence of polyacrylic acid, sporadic nucleation and crystallization was observed via optical microscopy.

Sukun Zhang; K. E. Gonsalves

1995-01-01

210

Mucoadhesive 4-carboxybenzenesulfonamide-chitosan with antibacterial properties.  

PubMed

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

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

2013-04-15

211

Synthesis and study of water-soluble chitosan-O-poly(ethylene glycol) graft copolymers  

Microsoft Academic Search

Novel chitosan-O-poly(ethylene glycol) graft copolymers were synthesized. Etherification of N-phthaloyl chitosan by poly(ethylene glycol) monomethyl ether (MPEG) iodide was carried out in dimethylformamide in the presence of silver oxide. Varying the ratio of MPEG iodide to chitosan, different degree of O-substitution of MPEG to monosaccharide residue of chitosan (5–197%) was obtained. Chemical structure of the new chitosan derivatives was confirmed

Natalija Gorochovceva; Ri?ardas Makuška

2004-01-01

212

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

213

Nitrate and phosphate removal by chitosan immobilized Scenedesmus.  

PubMed

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

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

2008-03-01

214

Antibacterial activity of polyacrylonitrile-chitosan electrospun nanofibers.  

PubMed

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

Kim, Sam Soo; Lee, Jaewoong

2014-02-15

215

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

216

Molecular spectroscopic analysis of nano-chitosan blend as biosensor  

NASA Astrophysics Data System (ADS)

Chitosan/starch and chitosan/gelatin of different ratios were prepared following casting method. FTIR results indicate the formation of hydrogen bonding which dedicates the prepared blends for interaction with wide range of molecules specially those of NH 2 and COOH terminals. The results obtained with molecular modeling PM3 model are in agreement with spectroscopic data. As a result of increasing starch and gelatin in chitosan blends HOMO-LUMO energy slightly decreased while total dipole moment increased. UV-vis spectroscopy indicated the suitability of chitosan/starch blend as a glycine sensor. Further enhancement in the sensing performance of chitosan/starch blend was achieved by introducing 5 nm TiO 2 into the blend.

Ibrahim, Medhat; Mahmoud, Abdel Aziz; Osman, Osama; Refaat, Ahmed; El-Sayed, El-Sayed M.

2010-11-01

217

Antioxidant effects of chitin, chitosan, and their derivatives.  

PubMed

Chitin, chitosan, and their derivatives are considered to promote diverse activities, including antioxidant, antihypertensive, anti-inflammatory, anticoagulant, antitumor and anticancer, antimicrobial, hypocholesterolemic, and antidiabetic effects, one of the most crucial of which is the antioxidant effect. By modulating and improving physiological functions, chitin, chitosan, and their derivatives may provide novel therapeutic applications for the prevention or treatment of chronic diseases. Antioxidant activity of chitin, chitosan, and their derivatives can be attributed to in vitro and in vivo free radical-scavenging activities. Antioxidant effect of chitin, chitosan, and their derivatives may be used as functional ingredients in food formulations to promote consumer health and to improve the shelf life of food products. This chapter presents an overview of the antioxidant activity of chitin, chitosan, and their derivatives with the potential utilization in the food and pharmaceutical industries. PMID:25300540

Ngo, Dai-Hung; Kim, Se-Kwon

2014-01-01

218

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

Microsoft Academic Search

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

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

2007-01-01

219

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

PubMed Central

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

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

2013-01-01

220

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

Microsoft Academic Search

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

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

2007-01-01

221

Chitosan removes toxic heavy metal ions from cigarette mainstream smoke  

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

222

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

PubMed

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

223

Chitin, chitosan, and its derivatives for wound healing: old and new materials.  

PubMed

Chitin (?-(1-4)-poly-N-acetyl-D-glucosamine) is widely distributed in nature and is the second most abundant polysaccharide after cellulose. It is often converted to its more deacetylated derivative, chitosan. Previously, many reports have indicated the accelerating effects of chitin, chitosan, and its derivatives on wound healing. More recently, chemically modified or nano-fibrous chitin and chitosan have been developed, and their effects on wound healing have been evaluated. In this review, the studies on the wound-healing effects of chitin, chitosan, and its derivatives are summarized. Moreover, the development of adhesive-based chitin and chitosan are also described. The evidence indicates that chitin, chitosan, and its derivatives are beneficial for the wound healing process. More recently, it is also indicate that some nano-based materials from chitin and chitosan are beneficial than chitin and chitosan for wound healing. Clinical applications of nano-based chitin and chitosan are also expected. PMID:25780874

Azuma, Kazuo; Izumi, Ryotaro; Osaki, Tomohiro; Ifuku, Shinsuke; Morimoto, Minoru; Saimoto, Hiroyuki; Minami, Saburo; Okamoto, Yoshiharu

2015-01-01

224

Evaluation of Hemagglutination Activity of Chitosan Nanoparticles Using Human Erythrocytes  

PubMed Central

Chitosan is a polysaccharide composed of randomly distributed chains of ?-(1-4) D-glucosamine and N-acetyl-D-glucosamine. This compound is obtained by partial or total deacetylation of chitin in acidic solution. The chitosan-based hemostatic agents have been gaining much attention in the management of bleeding. The aim of this study was to evaluate in vitro hemagglutination activity of chitosan nanoparticles using human erythrocytes. The preparation of nanoparticles was achieved by ionotropic gelification technique followed by neutralization with NaOH 1?mol/L?1. The hemagglutination activity was performed on a solution of 2% erythrocytes (pH 7.4 on PBS) collected from five healthy volunteers. The hemolysis determination was made by spectrophotometric analysis. Chitosan nanoparticle solutions without NaOH addition changed the reddish colour of the wells into brown, suggesting an oxidative reaction of hemoglobin and possible cell lysis. All neutralized solutions of chitosan nanoparticles presented positive haemagglutination, without any change in reaction color. Chitosan nanoparticles presented hemolytic activity ranging from 186.20 to 223.12%, while neutralized solutions ranged from 2.56 to 72.54%, comparing to distilled water. Results highlight the need for development of new routes of synthesis of chitosan nanoparticles within human physiologic pH.

de Lima, Jefferson Muniz; Sarmento, Ronaldo Rodrigues; de Souza, Joelma Rodrigues; Brayner, Fábio André; Feitosa, Ana Paula Sampaio; Padilha, Rafael; Alves, Luiz Carlos; Porto, Isaque Jerônimo; Batista, Roberta Ferreti Bonan Dantas; de Oliveira, Juliano Elvis; de Medeiros, Eliton Souto; Bonan, Paulo Rogério Ferreti; Castellano, Lúcio Roberto

2015-01-01

225

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

226

Isolation of chitosan from Ganoderma lucidum mushroom for biomedical applications.  

PubMed

Chitin biopolymer production and its by-product chitosan show great potential. These biomaterials have great applicability in various fields because they are non-toxic, biodegradable, biocompatible, and have antimicrobial effects. The most common source of chitin and chitosan is the crustaceous shell; however, mushrooms are an alternative source for isolating these biopolymers because their cellular wall has a high content of chitin, which may be transformed into chitosan through a deacetylation reaction. The main objective of this research was to obtain chitosan through the deacetylation of chitin isolated from the Ganoderma lucidum basidiomycetes mushroom, which is obtained through biotechnological culture. The material characterization was performed using X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, and an evaluation of cytotoxicity comparing the results obtained with results for commercial chitosan. Protocol results showed that chitosan obtained from this mushroom had a significant similitude with commercial chitosan, yet the one obtained using P2 protocol was the one that rendered the best results: including diffractogram peaks, characteristic infrared analysis bands, and an 80.29 % degree of deacetylation. Cytotoxicity in vitro testing showed that the material was non-toxic; furthermore, it rendered very promising information regarding the evaluation of future applications of this biomaterial in the field of biomedicine. PMID:25716022

Mesa Ospina, Natali; Ospina Alvarez, Sandra Patricia; Escobar Sierra, Diana Marcela; Rojas Vahos, Diego Fernando; Zapata Ocampo, Paola Andrea; Ossa Orozco, Claudia Patricia

2015-03-01

227

Rheological and structural studies of carboxymethyl derivatives of chitosan  

SciTech Connect

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

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

2014-05-15

228

Synthesis and properties of Chitosan-silica hybrid aerogels  

SciTech Connect

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

Ayers, Michael R.; Hunt, Arlon J.

2001-06-01

229

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

230

Chitosan-based nanofibrous membranes for antibacterial filter applications.  

PubMed

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

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

2013-01-30

231

Evaluation of hemagglutination activity of chitosan nanoparticles using human erythrocytes.  

PubMed

Chitosan is a polysaccharide composed of randomly distributed chains of ?-(1-4) D-glucosamine and N-acetyl-D-glucosamine. This compound is obtained by partial or total deacetylation of chitin in acidic solution. The chitosan-based hemostatic agents have been gaining much attention in the management of bleeding. The aim of this study was to evaluate in vitro hemagglutination activity of chitosan nanoparticles using human erythrocytes. The preparation of nanoparticles was achieved by ionotropic gelification technique followed by neutralization with NaOH 1?mol/L(-1). The hemagglutination activity was performed on a solution of 2% erythrocytes (pH 7.4 on PBS) collected from five healthy volunteers. The hemolysis determination was made by spectrophotometric analysis. Chitosan nanoparticle solutions without NaOH addition changed the reddish colour of the wells into brown, suggesting an oxidative reaction of hemoglobin and possible cell lysis. All neutralized solutions of chitosan nanoparticles presented positive haemagglutination, without any change in reaction color. Chitosan nanoparticles presented hemolytic activity ranging from 186.20 to 223.12%, while neutralized solutions ranged from 2.56 to 72.54%, comparing to distilled water. Results highlight the need for development of new routes of synthesis of chitosan nanoparticles within human physiologic pH. PMID:25759815

de Lima, Jefferson Muniz; Sarmento, Ronaldo Rodrigues; de Souza, Joelma Rodrigues; Brayner, Fábio André; Feitosa, Ana Paula Sampaio; Padilha, Rafael; Alves, Luiz Carlos; Porto, Isaque Jerônimo; Batista, Roberta Ferreti Bonan Dantas; de Oliveira, Juliano Elvis; de Medeiros, Eliton Souto; Bonan, Paulo Rogério Ferreti; Castellano, Lúcio Roberto

2015-01-01

232

Oxaliplatin-chitosan nanoparticles induced intrinsic apoptotic signaling pathway: a "smart" drug delivery system to breast cancer cell therapy.  

PubMed

This study was to investigate "smart" pH-responsive drug delivery system (DDS) based on chitosan nano-carrier for its potential intelligent controlled release and enhancing chemotherapeutic efficiency of Oxalipaltin. Oxaliplatin was loaded onto chitosan by forming complexes with degradable to construct nano-carrier as a DDS. Oxaliplatin was released from the DDS much more rapidly at pH 4.5 than at pH 7.4, which is a desirable characteristic for tumor-targeted drug delivery. Furthermore, the possible intrinsic apoptotic signaling pathway was explored by Western blot. It was found that expression of Bax, Bik, cytochrome C, caspase-9 and -3 was significantly up-regulated while the Bcl-2 and Survivin were inhibited in breast cancer MCF-7 cells. For instance, nanoparticles inducing apoptosis in caspase-dependent manner indicate that chitosan nanoparticles could act as an efficient DDS importing Oxalipaltin to target cancer cells. These approaches suggest that "smart" Oxaliplatin delivery strategy is a promising approach to cancer therapy. PMID:24472507

Vivek, Raju; Thangam, Ramar; Nipunbabu, Varukattu; Ponraj, Thondhi; Kannan, Soundarapandian

2014-04-01

233

Chitosan-induced antiviral activity and innate immunity in plants.  

PubMed

Immunity represents a trait common to all living organisms, and animals and plants share some similarities. Therefore, in susceptible host plants, complex defence machinery may be stimulated by elicitors. Among these, chitosan deserves particular attention because of its proved efficacy. This survey deals with the antiviral activity of chitosan, focusing on its perception by the plant cell and mechanism of action. Emphasis has been paid to benefits and limitations of this strategy in crop protection, as well as to the potential of chitosan as a promising agent in virus disease control. PMID:25226839

Iriti, Marcello; Varoni, Elena Maria

2015-02-01

234

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. PMID:17722528

Bowman, Katherine; Leong, Kam W

2006-01-01

235

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

PubMed Central

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

2013-01-01

236

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

237

Inactivation of Heparin by Cationically Modified Chitosan  

PubMed Central

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

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

2014-01-01

238

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

239

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

240

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

PubMed Central

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

2014-01-01

241

Properties of Novel Hydroxypropyl Methylcellulose Films Containing Chitosan Nanoparticles  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

242

Emerging chitin and chitosan nanofibrous materials for biomedical applications  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

243

Chitosan based oligoamine polymers: synthesis, characterization, and gene delivery.  

PubMed

A series of chitosan-based oligoamine polymers was synthesized from N-maleated chitosan (NMC) via Michael addition with diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA) and linear polyethylenimine (M(n) 423), respectively. The resulted polymers exhibited well binding ability to condense plasmid DNA to form complexes with size ranging from 200 to 600 nm when the polymer/DNA weight ratio was above 7. The polymer/DNA complexes observed by scanning electron microscopy (SEM) exhibited a compact and spherical morphology. The cytotoxicity assay showed that the synthesized polymers were less toxic than that of PEI(25 K). The gene transfection effect of resulted polymers was evaluated in 293T and HeLa cells, and the results showed that the gene transfection efficiency of these polymers was better than that of chitosan. Moreover, the transfection efficiency was dependent on the length of the oligoamine side chains and the molecular weight of the chitosan derivatives. PMID:19303039

Lu, Bo; Wang, Chang-Fang; Wu, De-Qun; Li, Cao; Zhang, Xian-Zheng; Zhuo, Ren-Xi

2009-07-01

244

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

2014-08-21

245

Chitosan nanofibers fabricated by combined ultrasonic atomization and freeze casting.  

PubMed

Aligned chitosan nanofibers exhibiting diameters smaller than 100nm were easily prepared by combining ultrasonic atomization with freeze casting. A major advantage of this approach is the use of distilled water as main solvent. Scanning electron microscopy demonstrated that fiber diameter and morphology mainly depended on the atomizing tools, freezing temperature, and chitosan solution viscosity. Minimum diameter and uniform orientation were achieved using an electric flosser as an atomizing tool, liquid nitrogen as a coolant, 0.4wt% aqueous chitosan solution (molecular weight=22kDa), and a small amount of lactic acid as solvent at 0°C. The resulting chitosan nanofibers may find application in biomedical and food engineering. Moreover, this new technology may be applicable to other natural and synthetic water-soluble polymers. PMID:25817638

Wang, Yihan; Wakisaka, Minato

2015-05-20

246

S-protected thiolated chitosan: Synthesis and in vitro characterization  

PubMed Central

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

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

2012-01-01

247

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

248

Preparation of water soluble chitosan by hydrolysis using hydrogen peroxide.  

PubMed

Chitosan is not soluble in water, which limits its wide application particularly in the medicine and food industry. In the present study, water soluble chitosan (WSC) was prepared by hydrolyzing chitosan using hydrogen peroxide under the catalysis of phosphotungstic acid in homogeneous phase. Factors affecting hydrolysis were investigated and the optimal hydrolysis conditions were determined. The WSC structure was characterized by Fourier transform infrared spectroscopy. The resulting products were composed of chitooligosaccharides of DP 2-9. The WSC content of the product and the yield were 94.7% and 92.3% (w/w), respectively. The results indicate that WSC can be effectively prepared by hydrolysis of chitosan using hydrogen peroxide under the catalysis of phosphotungstic acid. PMID:23603076

Xia, Zhenqiang; Wu, Shengjun; Chen, Jinhua

2013-08-01

249

Synthesis of chitosan derivative with diethyldithiocarbamate and its antifungal activity.  

PubMed

With an aim to discover novel chitosan derivatives with enhanced antifungal properties compared with chitosan. Diethyl dithiocarbamate chitosan (EtDTCCS) was investigated and its structure was well identified. The antifungal activity of EtDTCCS against Alternaria porri (A. porri), Gloeosporium theae sinensis Miyake (G. theae sinensis), and Stemphylium solani Weber (S. solani) was tested at 0.25, 0.5, and 1.0 mg/mL, respectively. Compared with plain chitosan, EtDTCCS shows better inhibitory effect with 93.2% inhibitory index on G. theae sinensis at 1.0 mg/mL, even stronger than for polyoxin (82.5%). It was inferred derivatives of this kind may find potential applications for the treatment of various crop-threatening diseases. PMID:24530333

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

2014-04-01

250

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

251

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

PubMed

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

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

2015-03-01

252

Effect of chitosan on Salmonella Typhimurium in broiler chickens.  

PubMed

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

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

2014-02-01

253

Stability of trans-resveratrol incorporated in chitosan microspheres  

Microsoft Academic Search

trans-Resveratrol, (3,5,4'-trihydroxy-trans-stilbene), a phenolic compound present in some plant species, have been shown to posses antioxidative, anticarcinogenic and antitumour properties. However, under UV light, it turns into -cis form and looses its bioactivity.This study aims to increase the stability of trans-Resveratrol by loading it into chitosan microspheres. Within this context, the trans-Resveratrol loaded chitosan microspheres was produced by spray drying

D. Altiok; E. Altiok; Ouz Bayraktar; F. Tihminlioglu

2009-01-01

254

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

255

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

256

Recovery of recombinant Escherichia coli by chitosan-conjugated magnetite  

Microsoft Academic Search

Magnetic separation of a recombinant Escherichia coli harboring the ?-galactosidase gene was investigated. We prepared a chitosan-conjugated magnetite (chitosan-mag) that disperses well in aqueous solution. After adding it to a cell suspension, it can recover various microorganisms including E. coli as the precipitant within only 1min. Over 90% of E. coli cells were recovered in a wide pH range from

Hiroyuki Honda; Atsushi Kawabe; Masashige Shinkai; Takeshi Kobayashi

1999-01-01

257

Adsorption of chromium onto cross-linked chitosan  

Microsoft Academic Search

While chitosan biopolymer from crustacean shells is recognized as a good adsorbent of metals from aqueous solutions, chemical cross-linking is necessary to avoid biopolymer solubility in acidic medium. Adsorption of chromium onto cross-linked chitosan is realized by means of analysis of pH influence, particle size, adsorbent weight, concentration and oxidation state of metal. Concentrations of chromium in solution are determined

Graciela Rojas; Jorge Silva; Jaime A. Flores; Angélica Rodriguez; Martha Ly; Holger Maldonado

2005-01-01

258

Enhanced Topical Delivery of Terbinafine Hydrochloride with Chitosan Hydrogels  

Microsoft Academic Search

Chitosan-based carriers have important potential applications for the administration of drugs. In the present study, topical\\u000a gel formulations of terbinafine hydrochloride (T-HCl) were prepared using different types of chitosan at different molecular\\u000a weight, and the antifungal inhibitory activity was evaluated to suggest an effective formulation for the treatment of fungal\\u000a infections. The characteristics of gel formulations were determined with viscosity

?pek Özcan; Özlem Abac?; Alev Haliki Uztan; Buket Aksu; Hayal Boyac?o?lu; Tamer Güneri; Özgen Özer

2009-01-01

259

Preparation and characterization of chitosan microspheres for doxycycline delivery  

Microsoft Academic Search

Doxycycline-loaded chitosan microspheres were developed using a novel water-in-oil emulsion technique, involving oil phase ionic gelation. Microspheres were prepared by using 6% v\\/v of chitosan (3% w\\/v in acetic acid), soya oil–n-octanol oil mixture (1:2 v\\/v) as continuous phase and 5% span 80 as emulsifier. Doxycycline was entrapped by equilibrium swelling method with 8.4% total entrapment. The drug-loaded spheres were

S. Shanmuganathan; N. Shanumugasundaram; N. Adhirajan; T. S. Ramyaa Lakshmi; Mary Babu

2008-01-01

260

Preparation of alginate\\/galactosylated chitosan scaffold for hepatocyte attachment  

Microsoft Academic Search

Galactose-carrying lactobionic acid was covalently coupled with chitosan for determining hepatocyte specificity. Galactosylated chitosan (GC) was reacted with Ca-alginate (ALG) gel through the electrostatic interaction of carboxylic groups of alginate with amine groups of GC. Highly porous, three-dimensional sponge composed of ALG and GC was prepared to provide specific hepatocyte recognition signals and enhance the mechanical property of the ALG

Taek Woong Chung; Jun Yang; Toshihiro Akaike; Kwang Yong Cho; Jae Woon Nah; Su Il Kim; Chong Su Cho

2002-01-01

261

Effect of chitosan on dyeing of chemical fibres  

Microsoft Academic Search

Treatment with chitosan before dyeing significantly improves the properties of fabrics made of polyester and polyamide fibres:\\u000a it increases the intensity and fastness of the colors of the fabrics; the capillary and sorption properties of the fabrics\\u000a are improved due to swelling of the chitosan film on the fibre; the mechanism of dyeing textile materials is significantly\\u000a altered by not

I. I. Manyukova; V. V. Safonov

2009-01-01

262

Effect of Chitosan on Salmonella Typhimurium in Broiler Chickens  

PubMed Central

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

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

2014-01-01

263

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

264

Galactosylated chitosan/DNA nanoparticles prepared using water-soluble chitosan as a gene carrier.  

PubMed

Water-soluble chitosan (WSC) was used to increase the stability of chitosan in water and decrease the cytotoxicity induced by acetic acid. Lactobionic acid (LA) bearing galactose group was coupled with WSC for hepatocytes specificity. The composition of galactose in galactosylated chitosan (GC) was determined by NMR spectroscopy. The GC was complexed with plasmid DNA in various GC/DNA (N/P) charge ratios and the resulting complex was characterized by dynamic light scattering, gel retardation, and turbidity to determine the particle sizes, complex formation, and complex stability, respectively. Cytotoxicity and transfection efficiency of GC were also studied in cultured HepG2 human hepatoblastoma cell line and HeLa human cervix epithelial carcinoma cells. The complete GC/DNA complex was formed at the charge ratio of 5 and the GC/DNA complex to DNase I resistance was obtained. Particle sizes decreased with increasing charge ratio of GC to DNA and had a minimum value around 120 nm at the charge ratio of 5. And no significant difference in particle sizes from the charge ratio of 5-20 was found. The suspension of GC/DNA complexes exhibited no significant change in turbidity at the charge ratios of 10, indicating the complete shielding of DNA charge. Cytotoxicity study showed that GC prepared by the water-soluble chitosan had no cytotoxic effects on cells. And transfection efficiency into HepG2, which has asialoglycoprotein receptors (ASGP-R), was higher than that into HeLa without ASGP-R. PMID:15020154

Kim, Tae Hee; Park, In Kyu; Nah, Jae Woon; Choi, Yun Jaie; Cho, Chong Su

2004-08-01

265

Coating cortical bone allografts with periosteum-mimetic scaffolds made of chitosan, trimethyl chitosan, and heparin.  

PubMed

Bone allografts have very limited healing leading to high rates of failure from non-union, fracture, and infection. The limited healing of bone allografts is due in large part to devitalization and removal of the periosteum, which removes osteogenic cells and osteoinductive signals. Here we report techniques for directly coating cortical bone with tissue scaffolds, and evaluate the scaffolds' capacity to support osteoprogenitor cells. Three types of coatings are investigated: N,N,N-trimethyl chitosan-heparin polyelectrolyte multilayers, freeze-dried porous chitosan foam coatings, and electrospun chitosan nanofibers. The freeze-dried and electrospun scaffolds are also further modified with polyelectrolyte multilayers. All of the scaffolds are durable to subsequent aqueous processing, and are cytocompatible with adipose-derived stem cells. Alkaline phosphatase and receptor activator of nuclear factor kappa-B ligand expression at days 7 and 21 suggest that these scaffolds support an osteoprogenitor phenotype. These scaffolds could serve as periosteum mimics, deliver osteoprogenitor cells, and improve bone allograft healing. PMID:25817653

Romero, Raimundo; Chubb, Laura; Travers, John K; Gonzales, Timothy R; Ehrhart, Nicole P; Kipper, Matt J

2015-05-20

266

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

PubMed

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

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

2013-01-01

267

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

268

A biomimetic chitosan derivates: preparation, characterization and transdermal enhancement studies of N-arginine chitosan.  

PubMed

A novel arginine-rich chitosan (CS) derivates mimicked cell penetration peptides; N-Arginine chitosan (N-Arg-CS) was prepared by two reaction methods involving activated L-arginine and the amine group on the chitosan. FTIR spectra showed that arginine was chemically coupled with CS. Elemental analysis estimated that the degrees of substitution (DS) of arginine in CS were 6%, 31.3% and 61.5%, respectively. The drug adefovir was chosen as model and its permeation flux across excised mice skin was investigated using a Franz diffusion cell. The results showed that the most effective enhancer was 2% (w/v) concentration of 10 kDa N-Arg-CS with 6% DS. At neutral pH, the cumulative amount of adefovir permeated after 12 hours was 2.63 ± 0.19 mg cm(-2) which was 5.83-fold more than adefovir aqueous solution. Meanwhile N-Arg-CS was 1.83, 2.22, and 2.45 times more effective than Azone, eucalyptus and peppermint, respectively. The obtained results suggest that N-Arg-CS could be a promising transdermal enhancer. PMID:21829153

Lv, Hui-Xia; Zhang, Zhen-Hai; Wang, Xiao-Pan; Cheng, Qing-Qing; Wang, Wei; Huang, Xu-Hui; Zhou, Jian-Ping; Zhang, Qiang; Hou, Lu-Lu; Huo, Wei

2011-01-01

269

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

270

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

271

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

272

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

273

Development of thermoplastic starch blown film by incorporating plasticized chitosan.  

PubMed

The objective of the present work was to improve blown film extrusion processability and properties of thermoplastic starch (TPS) film by incorporating plasticized chitosan, with a content of 0.37-1.45%. The effects of chitosan on extrusion processability and melt flow ability of TPS, as well as that on appearance, optical properties, thermal properties, viscoelastic properties and tensile properties of the films were investigated. The possible interactions between chitosan and starch molecules were evaluated by FTIR and XRD techniques. Chitosan and starch molecules could interact via hydrogen bonds, as confirmed from the blue shift of OH bands and the reduction of V-type crystal formation. Although the incorporation of chitosan caused decreased extensibility and melt flow ability, as well as increased yellowness and opacity, the films possessed better extrusion processability, increased tensile strength, rigidity, thermal stability and UV absorption, as well as reduced water absorption and surface stickiness. The obtained TPS/chitosan-based films offer real potential application in the food industry, e.g. as edible films. PMID:25439934

Dang, Khanh Minh; Yoksan, Rangrong

2015-01-22

274

Rheological study of chitosan acetate solutions containing chitin nanofibrils.  

PubMed

Rheological properties of chitosan acetate solutions containing chitin nanofibrils (n-chitin) and biocompatible plasticizers intended for preparation of biodegradable films are reported in the steady, oscillatory and transient shear flow. The experiments were performed on slurries with an optimum proportion of 65/35 wt.% between chitosan and n-chitin in the films which was determined from our results of mechanical properties and absorption of water vapor. The time-dependent dynamic experiments revealed the chitin nanofibrils as an effective "gelling agent" of chitosan phase. The phenomenon is explained by a chitosan-like surface of n-chitin and by the interactions inducing orientational cooperativity of chitosan molecules dissolved in close neighborhood of the anisotropic chitin nanofibrils. Additions of glycerol or poly(ethylene glycol), improving mechanical properties of the films, delay significantly the onset of gelation of chitosan/n-chitin slurries. The effect is induced by an increase in viscosity of the slurries and by their enhanced chaotropic character. PMID:25129805

Mikešová, Jana; Hašek, Jind?ich; Tishchenko, Galina; Morganti, Pierfrancesco

2014-11-01

275

Chitosan Composites for Bone Tissue Engineering—An Overview  

PubMed Central

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

Venkatesan, Jayachandran; Kim, Se-Kwon

2010-01-01

276

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

277

Chitosan as a sustainable organocatalyst: a concise overview.  

PubMed

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

El Kadib, Abdelkrim

2015-01-01

278

Fluorescent imino and secondary amino chitosans as potential sensing biomaterials.  

PubMed

A variety of fluorescent imino and secondary amino chitosans were synthesized under very mild conditions by reaction of the biopolymer amino functions with aromatic aldehydes in an acidified methanolic suspension. Simultaneous reactions of several aldehydes with chitosan were successfully carried out, and kinetic studies showed that 1-pyrenecarboxaldehyde reacts the fastest among them. An unprecedented study on the evaluation of the degree of N-substitution (DS, ranging from 31.7% to 12.0%) for the chitosan Schiff bases by using solid state CPMAS (13)C NMR is performed. A linear correlation between the DS obtained for the secondary amino chitosans by (1)H NMR (55.3-10.2%) and those obtained by CPMAS (13)C NMR (34.4-13.8%) has allowed us to calculate an empirical correlation factor that could be applied on chitosan-based aromatic systems. The new chiral-labelled chitosan derivatives exhibit a stable fluorescent behaviour, which was used to explore solvent sensoring applications. PMID:25843861

Jatunov, Sorel; Franconetti, Antonio; Prado-Gotor, Rafael; Heras, Angeles; Mengíbar, Marian; Cabrera-Escribano, Francisca

2015-06-01

279

Synthesis and anticoagulant activity of the quaternary ammonium chitosan sulfates.  

PubMed

Quaternary ammonium chitosan sulfates with diverse degrees of substitution (DS) ascribed to sulfate groups between 0.52 and 1.55 were synthesized by reacting quaternary ammonium chitosan with an uncommon sulfating agent (N(SO(3)Na)(3)) that was prepared from sodium bisulfite (NaHSO(3)) through reaction with sodium nitrite (NaNO(2)) in the aqueous system homogeneous. The structures of the derivatives were characterized by FTIR, (1)H NMR and (13)C NMR. The factors affecting DS of quaternary ammonium chitosan sulfates which included the molar ratio of NaNO(2) to quaternary ammonium chitosan, sulfated temperature, sulfated time and pH of sulfated reaction solution were investigated in detail. Its anticoagulation activity in vitro was determined by an activated partial thromboplastin time (APTT) assay, a thrombin time (TT) assay and a prothrombin time (PT) assay. Results of anticoagulation assays showed quaternary ammonium chitosan sulfates significantly prolonged APTT and TT, but not PT, and demonstrated that the introduction of sulfate groups into the quaternary ammonium chitosan structure improved its anticoagulant activity obviously. The study showed its anticoagulant properties strongly depended on its DS, concentration and molecular weight. PMID:21996571

Fan, Lihong; Wu, Penghui; Zhang, Jinrong; Gao, Song; Wang, Libo; Li, Mingjia; Sha, Mingming; Xie, Weiguo; Nie, Min

2012-01-01

280

Synthesis and antifungal activity of thiadiazole-functionalized chitosan derivatives.  

PubMed

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

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

2013-05-24

281

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

282

Palladium adsorbing properties of UV-curable chitosan derivatives and surface analysis of chitosan-containing paint.  

PubMed

The results of X-ray photoelectron spectroscopy (XPS) analyses indicated that palladium chloride was adsorbed on a plastic surface coated with a chitosan-containing paint (C-Paint), and was completely reduced to Pd(0) after reduction with dimethylamine-borane. To improve the stability and hardening properties of C-Paint, UV-curable chitosan derivatives, such as N-[3-methoxy-4-(2-hydroxy-3-methacryloyloxypropoxy)phenyl]methylated chitosan and N-(3-methoxy-4-methacryloyloxyphenyl)methylated chitosan, were synthesized. The derivatives showed better affinity for organic solvents. After UV irradiation for 20s, an acidic solution of these derivatives was transformed to a gel, and the dried films exhibited good palladium(II) adsorption at pH 1.1. PMID:18155291

Renbutsu, E; Okabe, S; Omura, Y; Nakatsubo, F; Minami, S; Shigemasa, Y; Saimoto, H

2008-07-01

283

Immobilisation of Fenugreek ?-amylase on chitosan/PVP blend and chitosan coated PVC beads: a comparative study.  

PubMed

A Box-Behnken design of Response Surface Methodology (RSM) was utilised for optimisation of parameters affecting immobilisation of Fenugreek ?-amylase on chitosan coated PVC (polyvinyl chloride) beads and beads made from chitosan/PVP (polyvinylpyrrolidone) blend, which resulted in 85.2% and 81% immobilisation efficiency, respectively. Immobilisation resulted in shift of pH optima while the optimum temperature remained unaffected. Enhancement in thermal stability of the enzyme was observed on conjugation with both the matrices. The immobilised enzyme appeared suitable for industrial applications due to the non-toxic nature of chosen matrices, ease of immobilisation procedure, enhanced stability and reusability with retention of 72% and 60% residual activity after 10 uses for the enzyme immobilised on chitosan coated PVC beads and on the beads of chitosan/PVP blend, respectively. PMID:25442629

Srivastava, Garima; Roy, Sonam; Kayastha, Arvind M

2015-04-01

284

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

PubMed Central

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

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

2014-01-01

285

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

E-print Network

, modification, and characterization of chitosan films, and we review a number of demonstrated chitosan. These types of micro- devices typically need to be functionalized with biomolecules such as DNA, enzymes

Rubloff, Gary W.

286

A novel soft and cotton-like chitosan-sugar nanoscaffold.  

PubMed

A novel type of chitosan nanoscaffold with a soft and cotton-like appearance is proposed. The key to success is based on two points: (i) the change in morphology of chitin whisker to chitosan nanoscaffold and (ii) the surface modification of the nanoscaffold chitosan with a sugar unit. Simple deacetylation of chitin whisker gives a colloidal solution of chitosan, of which the chitosan is in a nanoscaled scaffold. Surface functionalization of the chitosan nanoscaffold with lactose or maltose via a heterogeneous system in water at room temperature results in a soft and cotton-like chitosan containing mesopores. As all steps are organic solvent free, this chitosan-sugar nanoscaffold might be a promising material for biopolymer-supported tissue engineering. PMID:16794997

Phongying, Sasiprapha; Aiba, Sei-ichi; Chirachanchai, Suwabun

2006-10-15

287

PEGylated chitosan complexes DNA while improving polyplex colloidal stability and gene transfection efficiency.  

PubMed

Chitosan is widely explored as a gene delivery vehicle due to its ability to condense DNA, facilitate transport, and subsequent release allowing gene expression, as well as protecting the DNA. Here, we investigate the enhancement of chitosan-DNA dispersion stability while maintaining transfection efficacy by PEGylation of chitosan. Molecular properties of fully deacetylated chitosans and degree of PEGylation were investigated with respect to compaction of DNA, stability and transfection efficacy. Each of the three chitosan samples with varying chain lengths was PEGylated at three different degrees. The chitosans with degree of PEGylation from 0.6 to 1.9% made polyplexes with DNA. PBS induced colloidal aggregation of polyplexes with initial radius of about 100 nm observed for nonPEGylated chitosans was suppressed for 1.9% PEGylated chitosans. The observed increase in transfection efficacy coinciding with increased polyplex colloidal stability suggests that aggregation of gene-delivery packages may reduce the transfection efficacy. PMID:23544560

Maurstad, Gjertrud; Stokke, Bjørn T; Vårum, Kjell M; Strand, Sabina P

2013-04-15

288

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

289

Chitosan-phospholipid blend for sustained and localized delivery of docetaxel to the peritoneal cavity.  

PubMed

Localized and sustained delivery of chemotherapeutics presents a "magic bullet" effect by providing high drug concentrations at the target site, extended drug exposure and reduced systemic toxicity. In the present study, an injectable chitosan-phospholipid (PoLi(gel)) blend is put forth as a strategy to achieve sustained and localized delivery of docetaxel (DTX) following intraperitoneal (IP) administration. The stability of the blend was confirmed in vitro, by turbidity measurements and attributed to specific molecular interactions and the organization of the materials within the blend, as evidenced by FTIR analysis and confocal laser scanning microscopy, respectively. The chitosan and phospholipid were found to colocalize in regions surrounding a mean object area of 11.2mum(2) with colocalization coefficients of 43% and 46% for the chitosan and phospholipid, respectively. The PoLi(gel) blend afforded sustained drug release as seen both in vitro (2.4+/-0.7% DTX per day) and in vivo (4.4+/-0.7% DTX per day). Constant concentrations of DTX were observed over a 2-week period in plasma and relevant peritoneal tissues, with no signs of toxicity or inflammation, following IP administration of the blend in healthy CD-1 mice. At DTX doses of 28.8 and 19.2mg/kg, the blend showed significant tumor inhibition of 87.3+/-9.3% and 74.1+/-25.9%, respectively, in a murine xenograft model of human ovarian adenocarcinoma. This localized delivery system has shown excellent potential for sustained IP treatment of cancers, such as ovarian, that reside in the peritoneal cavity. PMID:19442712

Zahedi, Payam; De Souza, Raquel; Piquette-Miller, Micheline; Allen, Christine

2009-07-30

290

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

PubMed

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

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

2015-01-01

291

Chitosan–RGDSGGC conjugate as a scaffold material for musculoskeletal tissue engineering  

Microsoft Academic Search

In the present study, we have developed a novel and versatile method for the preparation of chitosan-peptide complex based on the selective reaction of chitosan with 2-iminothiolane. The new type of SH-chitosan derivative showed an excellent solubility to aqueous solution even in the alkaline conditions. This characteristic greatly facilitated further modification study of chitosan with a variety of bioactive substances.

Tatsuya Masuko; Norimasa Iwasaki; Shintaro Yamane; Tadanao Funakoshi; Tokifumi Majima; Akio Minami; Noriko Ohsuga; Takashi Ohta; Shin-Ichiro Nishimura

2005-01-01

292

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

Microsoft Academic Search

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

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

2008-01-01

293

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

Microsoft Academic Search

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

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

1998-01-01

294

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

Microsoft Academic Search

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

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

2001-01-01

295

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

296

Nutraceuticals in lipid-lowering treatment: a narrative review on the role of chitosan.  

PubMed

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

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

2015-05-01

297

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

PubMed

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

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

2013-06-01

298

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

PubMed Central

By targeted deletion of the polyglutamate operon (pga) in Bacillus licheniformis F11, a derivative form, F11.1 (?pga), was obtained that, along with lacking polyglutamate (PGA) formation, displayed enhanced proteolytic activities. The phenotypic properties were maintained in a strain in which the chiBA operon was additionally deleted: F11.4 (?chiBA ?pga). These genetically modified strains, carrying the ?pga deletion either alone (F11.1) or together with the ?chiBA (F11.4) deletion, were used in fermentations (20-liter scale) aiming at the deproteinization of shrimp shells in order to obtain long-chain chitin. After chemical deacetylation, the resulting chitosan samples were analyzed by nuclear magnetic resonance spectroscopy, size exclusion chromatography, and viscometry and compared to a chitosan preparation that was produced in parallel by chemical methods by a commercial chitosan supplier (GSRmbH). Though faint lipid impurities were present in the fermented polysaccharides, the viscosity of the material produced with the double-deletion mutant F11.4 (?pga ?chiBA) was higher than that of the chemically produced and commercially available samples (Cognis GmbH). Thus, enhanced proteolytic activities and a lack of chitinase activity render the double mutant F11.4 a powerful tool for the production of long-chain chitosan. PMID:20971870

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

2010-01-01

299

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

PubMed

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

Kubiak, Tomasz

2014-01-01

300

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

PubMed

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

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

2014-10-01

301

A new linear potentiometric titration method for the determination of deacetylation degree of chitosan  

Microsoft Academic Search

The degree of deacetylation (DD) is one of the most important properties of chitosan. Therefore, a simple, rapid and reliable method for the determination of DD of chitosan is essential. In this report, two new potentiometric titration functions are derived for the determination of DD of chitosan. The effects of the precipitation and the errors induced in pH measurement are

Xuan Jiang; Lirong Chen; Wei Zhong

2003-01-01

302

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

Microsoft Academic Search

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

Sureerat Phuvasate; Yi-Cheng Su

2010-01-01

303

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

Microsoft Academic Search

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

Amita Ummadisingu; Suresh Gupta

2012-01-01

304

The antifungal properties of chitosan in laboratory media and apple juice  

Microsoft Academic Search

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

S. Roller; N. Covill

1999-01-01

305

Preparation and immunological effectiveness of a swine influenza DNA vaccine encapsulated in chitosan nanoparticles  

Microsoft Academic Search

Preparation conditions of a DNA vaccine against swine influenza encapsulated in chitosan nanoparticles were determined. The nanoparticles were prepared according to a complex coacervation method using chitosan as a biodegradable matrix forming polymer. Under the preparation conditions, chitosan nanoparticles containing the DNA vaccine were produced with good morphology, high encapsulation rate and high stability. Transfection test indicated that the vaccine

Kai Zhao; Xingming Shi; Yan Zhao; Haixia Wei; Qingshen Sun; Tingting Huang; Xiaoyan Zhang; Yunfeng Wang

2011-01-01

306

Response of gladiolus ( Gladiolus spp) plants after exposure corms to chitosan and hot water treatments  

Microsoft Academic Search

The state of Morelos, Mexico has gradually become an important producer of gladiolus. Some preconditioning treatments of corms are empirically done causing uneven emergence and low quality of flowers. In this investigation, before planting, gladiolus corms var. ‘Blanca Borrego’ were dipped in chitosan (chitosan reagent and commercial chitosan Biorend®), in hot water at various temperatures and in treatments combined with

Margarita Ramos-García; Salvador Ortega-Centeno; Ana N. Hernández-Lauzardo; Elsa Bosquez-Molina; Silvia Bautista-Baños

2009-01-01

307

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

308

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

309

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

PubMed Central

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

2012-01-01

310

Chitosan for gene delivery and orthopedic tissue engineering applications.  

PubMed

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

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

2013-01-01

311

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

312

Intranasal Delivery of Chitosan Nanoparticles for Migraine Therapy  

PubMed Central

Objective The objective of the research was to formulate and evaluate sumatriptan succinate-loaded chitosan nanoparticles for migraine therapy in order to improve its therapeutic effect and reduce dosing frequency. Material and Methods The Taguchi method design of experiments (L9 orthogonal array) was applied to obtain the optimized formulation. The sumatriptan succinate-loaded chitosan nanoparticles (CNPs) were prepared by ionic gelation of chitosan with tripolyphosphate anions (TPP) and Tween 80 as surfactant. Results The CNPs had a mean size of 306.8 ± 3.9 nm, a zeta potential of +28.79 mV, and entrapment efficiency of 75.4 ± 1.1%. The in vitro drug release of chitosan nanoparticles was evaluated in phosphate buffer saline pH 5.5 using goat nasal mucosa and found to be 76.7 ± 1.3% within 28 hours. Discussion The release of the drug from the nanoparticles was anomalous, showing non-Fickian diffusion indicating that drug release is controlled by more than one process i.e. the superposition of both phenomena, a diffusion-controlled as well as a swelling-controlled release. This is clearly due to the characteristics of chitosan which easily dissolves at low pH, thus a nasal pH range of 5.5 ± 0.5 supports it very well. The mechanism of pH-sensitive swelling involves protonation of the amine groups of chitosan at low pH. This protonation leads to chain repulsion, diffusion of protons and counter ions together with water inside the gel, and the dissociation of secondary interactions. Conclusion The results suggest that sumatriptan succinate-loaded chitosan nanoparticles are the most suitable mode of drug delivery for promising therapeutic action. PMID:24106677

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

2013-01-01

313

Chitosan/Interfering RNA nanoparticle mediated gene silencing in disease vector mosquito larvae.  

PubMed

Vector mosquitoes inflict more human suffering than any other organism-and kill more than one million people each year. The mosquito genome projects facilitated research in new facets of mosquito biology, including functional genetic studies in the primary African malaria vector Anopheles gambiae and the dengue and yellow fever vector Aedes aegypti. RNA interference- (RNAi-) mediated gene silencing has been used to target genes of interest in both of these disease vector mosquito species. Here, we describe a procedure for preparation of chitosan/interfering RNA nanoparticles that are combined with food and ingested by larvae. This technically straightforward, high-throughput, and relatively inexpensive methodology, which is compatible with long double stranded RNA (dsRNA) or small interfering RNA (siRNA) molecules, has been used for the successful knockdown of a number of different genes in A. gambiae and A. aegypti larvae. Following larval feedings, knockdown, which is verified through qRT-PCR or in situ hybridization, can persist at least through the late pupal stage. This methodology may be applicable to a wide variety of mosquito and other insect species, including agricultural pests, as well as other non-model organisms. In addition to its utility in the research laboratory, in the future, chitosan, an inexpensive, non-toxic and biodegradable polymer, could potentially be utilized in the field. PMID:25867635

Zhang, Xin; Mysore, Keshava; Flannery, Ellen; Michel, Kristin; Severson, David W; Zhu, Kun Yan; Duman-Scheel, Molly

2015-01-01

314

Development of chitosan-coated gold nanoflowers as SERS-active probes.  

PubMed

Surface-enhanced Raman scattering (SERS) has been intensely researched for many years as a potential technique for highly sensitive detection. This work, through the reduction of HAuCl(4) with pyrrole in aqueous solutions, investigated a facile one-pot synthesis of flower-like Au nanoparticles with rough surfaces. The formation process of the Au nanoflowers (AuNFs) was carefully studied, and a spontaneous assembly mechanism was proposed based on the time-course experimental results. The key synthesis strategy was to use pyrrole as a weak particle stabilizing and reducing agent to confine crystal growth in the limited ligand protection region. The nanometer-scale surface roughness of AuNFs provided several hot spots on a single particle, which significantly increased SERS enhancement. Good biocompatible stable Raman-active probes were synthesized by coating AuNFs with chitosan. The conservation of the SERS effects in living cells suggested that the chitosan-capped AuNFs could be suitable for highly sensitive detection and have potential for targeting of tumors in vivo. PMID:20720293

Xu, Dan; Gu, Jiangjiang; Wang, Weina; Yu, Xuehai; Xi, Kai; Jia, Xudong

2010-09-17

315

Preparation and Characterization of SDF-1?-Chitosan-Dextran Sulfate Nanoparticles.  

PubMed

Chitosan (CS) and dextran sulfate (DS) are charged polysaccharides (glycans), which form polyelectrolyte complex-based nanoparticles when mixed under appropriate conditions. The glycan nanoparticles are useful carriers for protein factors, which facilitate the in vivo delivery of the proteins and sustain their retention in the targeted tissue. The glycan polyelectrolyte complexes are also ideal for protein delivery, as the incorporation is carried out in aqueous solution, which reduces the likelihood of inactivation of the proteins. Proteins with a heparin-binding site adhere to dextran sulfate readily, and are, in turn, stabilized by the binding. These particles are also less inflammatory and toxic when delivered in vivo. In the protocol described below, SDF-1? (Stromal cell-derived factor-1?), a stem cell homing factor, is first mixed and incubated with dextran sulfate. Chitosan is added to the mixture to form polyelectrolyte complexes, followed by zinc sulfate to stabilize the complexes with zinc bridges. The resultant SDF-1?-DS-CS particles are measured for size (diameter) and surface charge (zeta potential). The amount of the incorporated SDF-1? is determined, followed by measurements of its in vitro release rate and its chemotactic activity in a particle-bound form. PMID:25650558

Bader, Andrew R; Li, Tina; Wang, Weiping; Kohane, Daniel S; Loscalzo, Joseph; Zhang, Ying-Yi

2015-01-01

316

Development of chitosan-coated gold nanoflowers as SERS-active probes  

NASA Astrophysics Data System (ADS)

Surface-enhanced Raman scattering (SERS) has been intensely researched for many years as a potential technique for highly sensitive detection. This work, through the reduction of HAuCl4 with pyrrole in aqueous solutions, investigated a facile one-pot synthesis of flower-like Au nanoparticles with rough surfaces. The formation process of the Au nanoflowers (AuNFs) was carefully studied, and a spontaneous assembly mechanism was proposed based on the time-course experimental results. The key synthesis strategy was to use pyrrole as a weak particle stabilizing and reducing agent to confine crystal growth in the limited ligand protection region. The nanometer-scale surface roughness of AuNFs provided several hot spots on a single particle, which significantly increased SERS enhancement. Good biocompatible stable Raman-active probes were synthesized by coating AuNFs with chitosan. The conservation of the SERS effects in living cells suggested that the chitosan-capped AuNFs could be suitable for highly sensitive detection and have potential for targeting of tumors in vivo.

Xu, Dan; Gu, Jiangjiang; Wang, Weina; Yu, Xuehai; Xi, Kai; Jia, Xudong

2010-09-01

317

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

Microsoft Academic Search

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

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

2007-01-01

318

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

Microsoft Academic Search

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

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

2011-01-01

319

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

PubMed

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

Wu, Shengjun

2014-04-01

320

[Preparation and characterization of chitosan membrane for solid phase microextraction technique].  

PubMed

Chitosan is a kind of natural polymers containing plenty of amido and hydoxy. The chitosan membrane is tough, and since the partition coefficient of chlorophyll between chitosan membrance and water is as high as 9,090, the chitosan membrane may beeasily manufactured as solid-phase microextraction membrane for the analysis of chlorophyll. The system may reach a complete equilibrium in 80 min. Then the membrane can be desorbed completely in 30 min in 5% NaOH with ultrasonic. Both IR and XRD indicated that hydrogen bonds between the molecules of chitosan were weakened and amido and hydoxy were considered as the keys during the process of extracting chlorophyll. PMID:16827331

Yang, Hong-li; Wang, Yi-ru; Zhuang, Zhi-xia; Wang, Xiao-ru

2006-01-01

321

Chitosan-nanosilica hybrid materials: Preparation and properties  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

322

High concentration honey chitosan electrospun nanofibers: Biocompatibility and antibacterial effects.  

PubMed

Honey nanofibers represent an attractive formulation with unique medicinal and wound healing advantages. Nanofibers with honey concentrations of <10% were prepared, however, there is a need to prepare nanofibers with higher honey concentrations to increase the antibacterial and wound healing effects. In this work, chitosan and honey (H) were cospun with polyvinyl alcohol (P) allowing the fabrication of nanofibers with high honey concentrations up to 40% and high chitosan concentrations up to 5.5% of the total weight of the fibers using biocompatible solvents (1% acetic acid). The fabricated nanofibers were further chemically crosslinked, by exposure to glutaraldehyde vapor, and physically crosslinked by heating and freezing/thawing. The new HP-chitosan nanofibers showed pronounced antibacterial activity against Staphylococcus aureus but weak antibacterial activity against Escherichia coli. The developed HP-chitosan nanofibers revealed no cytotoxicity effects on cultured fibroblasts. In conclusion, biocompatible, antimicrobial crosslinked honey/polyvinyl alcohol/chitosan nanofibers were developed which hold potential as effective wound dressing. PMID:25817652

Sarhan, Wessam A; Azzazy, Hassan M E

2015-05-20

323

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

324

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

325

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

326

Cartilage regeneration by novel polyethylene oxide/chitin/chitosan scaffolds.  

PubMed

This study presents the application of novel PEO/chitin/chitosan scaffolds for the cultivation of bovine knee chondrocytes (BKCs). The results reveled that the composition strongly affected physicochemical characteristics of the ternary scaffolds. Based on the contours of porosity, the percentage of void space in these scaffolds was estimated to be higher than 90%. In regard to mechanical strength, the composition of 50% chitin and 50% chitosan in the scaffold led to the maximum of Young's modulus. Moreover, large extensibility of the scaffolds occurred at the following range of the composition: PEO > 37.5%, chitin < 25%, and chitosan <62.5%. After cultivation of BKCs over 4 weeks, the percentage of biodegradation was normally between 30 and 60%. The formation of neocartilage was assessed by the amounts of BKCs, glycosaminoglycans and collagens in the cultured BKC-polymer constructs. Better chondrogenesis was obtained at the following range of the composition: 25% < PEO < 40%, 12.5% < chitin < 37.5%, and 30% < chitosan < 50%. Thus, the regeneration of cartilaginous components could be manipulated simply by controlling the composition of PEO, chitin, and chitosan in the hybrid scaffolds. PMID:18771317

Kuo, Yung-Chih; Ku, I-Nan

2008-10-01

327

In vitro damage of Candida albicans biofilms by chitosan  

PubMed Central

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

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

2014-01-01

328

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

329

Blood protein adsorption on sulfonated chitosan and ?-carrageenan films.  

PubMed

Many strategies have been reported to improve compatibility of biopolymers using chemical and physical modifications. One possibility is the introduction of sulfonate groups (R-SO3(-)) in the chitosan chain. Another biopolymer with similar characteristics to those of heparin is ?-carrageenan. This study proposed to investigate the application of these two polymers, based on their potential for globular protein adsorption (BSA and fibrinogen). Polymeric films of chitosan and ?-carrageenan were prepared; all films were characterized by elemental analyses, FTIR, XPS and SEM. Characterization techniques showed that the chitosan chain was modified and confirmed the existence of sulfonate groups, as well as in the ?-carrageenan chain, indicating surfaces with similar chemical properties to those of heparin. The effect of charge density was observed for each adsorption condition (BSA at pH 5.0 and 7.4). A more pronounced adsorption rate was observed at pH 5.0 than at pH 7.4 and equilibrium adsorption was achieved, in both cases, after approximately 20 min. The equilibrium data indicate a lower adsorption rate for the sulfonated chitosan film, in comparison to the other films. These results confirm the potential of modified chitosan for use in applications in which globular protein adsorption should be avoided. PMID:23911741

Lima, Pedro H L; Pereira, Saulo V A; Rabello, Rodrigo B; Rodriguez-Castellón, Enrique; Beppu, Marisa M; Chevallier, Pascale; Mantovani, Diego; Vieira, Rodrigo S

2013-11-01

330

Highly efficient adsorption of chlorophenols onto chemically modified chitosan  

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

331

Antifungal property of quaternized chitosan and its derivatives.  

PubMed

Five water-soluble chitosan derivatives were carried out by quaternizing either iodomethane or N-(3-chloro-2-hydroxypropyl) trimethylammonium chloride (Quat188) as a quaternizing agent under basic condition. The degree of quaternization (DQ) ranged between 28±2% and 90±2%. The antifungal activity was evaluated by using disc diffusion method, minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) methods against Trichophyton rubrum (T. rubrum), Trichophyton mentagrophyte (T. mentagrophyte), and Microsporum gypseum (M. gypseum) at pH 7.2. All quaternized chitosans and its derivatives showed more effective against T. rubrum than M. gypseum and T. mentagrophyte. The MIC and MFC values were found to range between 125-1000 ?g/mL and 500-4000 ?g/mL, respectively against all fungi. Our results indicated that the quaternized N-(4-N,N-dimethylaminocinnamyl) chitosan chloride showed highest antifungal activity against T. rubrum and M. gypseum compared to other quaternized chitosan derivatives. The antifungal activity tended to increase with an increase in molecular weight, degree of quaternization and hydrophobic moiety against T. rubrum. However, the antifungal activity was depended on type of fungal as well as chemical structure of the quaternized chitosan derivatives. PMID:22100980

Sajomsang, Warayuth; Gonil, Pattarapond; Saesoo, Somsak; Ovatlarnporn, Chitchamai

2012-01-01

332

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

333

Development and in vitro characterization of galactosylated low molecular weight chitosan nanoparticles bearing doxorubicin.  

PubMed

The aim of the present research was to evaluate the potential of galactosylated low molecular weight chitosan (Gal-LMWC) nanoparticles bearing positively charged anticancer, doxorubicin (DOX) for hepatocyte targeting. The chitosan from crab shell was depolymerized, and the lactobionic acid was coupled with LMWC using carbodiimide chemistry. The depolymerized and galactosylated polymers were characterized. Two types of Gal-LMWC(s) with variable degree of substitution were employed to prepare the nanoparticles using ionotropic gelation with pentasodium tripolyphosphate anions. Factors affecting nanoparticles formation were discussed. The nanoparticles were characterized by transmission electron microscopy and photon correlation spectroscopy and found to be spherical in the size range 106-320 nm. Relatively higher percent DOX entrapment was obtained for Gal-LMWC(s) nanoparticles than for LMWC nanoparticles. A further increase in drug entrapment was found with nanoparticles prepared by Gal-LMWC with higher degree of substitution. A hypothesis which correlates the ionic concentration of DOX in nanoparticles preparation medium and percent DOX entrapment in cationic polymer has been proposed to explain the enhanced DOX entrapment. In-vitro drug release study demonstrated an initial burst release followed by a sustained release. The targeting potential of the prepared nanoparticles was assessed by in vitro cytotoxicity study using the human hepatocellular carcinoma cell line (HepG(2)) expressing the ASGP receptors on their surfaces. The enthusiastic results showed the feasibility of Gal-LMWC(s) to entrap the cationic DOX and targeting potential of developed Gal-LMWC(s) nanoparticles to HepG(2) cell line. PMID:20414758

Jain, Nitin K; Jain, Sanjay K

2010-06-01

334

Improving effects of chitosan nanofiber scaffolds on osteoblast proliferation and maturation  

PubMed Central

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

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

2014-01-01

335

Carbon and nitrogen limitation increase chitosan antifungal activity in Neurospora crassa and fungal human pathogens.  

PubMed

Chitosan permeabilizes plasma membrane and kills sensitive filamentous fungi and yeast. Membrane fluidity and cell energy determine chitosan sensitivity in fungi. A five-fold reduction of both glucose (main carbon (C) source) and nitrogen (N) increased 2-fold Neurospora crassa sensitivity to chitosan. We linked this increase with production of intracellular reactive oxygen species (ROS) and plasma membrane permeabilization. Releasing N. crassa from nutrient limitation reduced chitosan antifungal activity in spite of high ROS intracellular levels. With lactate instead of glucose, C and N limitation increased N. crassa sensitivity to chitosan further (4-fold) than what glucose did. Nutrient limitation also increased sensitivity of filamentous fungi and yeast human pathogens to chitosan. For Fusarium proliferatum, lowering 100-fold C and N content in the growth medium, increased 16-fold chitosan sensitivity. Similar results were found for Candida spp. (including fluconazole resistant strains) and Cryptococcus spp. Severe C and N limitation increased chitosan antifungal activity for all pathogens tested. Chitosan at 100 ?g ml(-1) was lethal for most fungal human pathogens tested but non-toxic to HEK293 and COS7 mammalian cell lines. Besides, chitosan increased 90% survival of Galleria mellonella larvae infected with C. albicans. These results are of paramount for developing chitosan as antifungal. PMID:25749367

Lopez-Moya, Federico; Colom-Valiente, Maria F; Martinez-Peinado, Pascual; Martinez-Lopez, Jesus E; Puelles, Eduardo; Sempere-Ortells, Jose M; Lopez-Llorca, Luis V

2015-03-01

336

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

337

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

PubMed Central

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

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

2014-01-01

338

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

339

Chitosan-Copper (II) complex as antibacterial agent: synthesis, characterization and coordinating bond- activity correlation study  

NASA Astrophysics Data System (ADS)

The antimicrobial activity of chitosan is unstable and sensitive to many factors such as molecular weight. Recent investigations showed that low molecular weight chitosan exhibited strong bactericidal activities compared to chitosan with high molecular weight. Since chitosan degradation can be caused by the coordinating bond, we attempt to synthesize and characterize the chitosan-Cu (II) complex, and thereafter study the coordinating bond effect on its antibacterial activity against Salmonella enteritidis. Seven chitosan-copper complexes with different copper contents were prepared and characterized by FT-IR, UV-vis, XRD and atomic absorption spectrophotometry (AAS). Results indicated that for chitosan-Cu (II) complexes with molar ratio close to 1:1, the inhibition rate reached 100%.

Mekahlia, S.; Bouzid, B.

2009-11-01

340

Evaluation of chitosans and Pichia guillermondii as growth inhibitors of Penicillium digitatum.  

PubMed

Chitosans were obtained by room-temperature-homogeneous-deacetylation (RTHD) and freeze-pump-out-thaw-heterogeneous-deacetylation (FPT) from chitins purified from fermentations. Commercial chitosan was deacetylated by three-FPT-cycles. Chitosans and Pichia guillermondii were evaluated on the growth of Penicillium digitatum. Medium molecular weight (M(W)) chitosans displayed higher inhibitory activity against the yeast than low M(W) biopolymers. Chitosans with low degree of acetylation (DA) were inhibitory for yeast and mould. Therefore, a low M(W) and high DA chitosan was selected for use against moulds combined with yeasts. Biopolymer and yeasts presented an additive effect, since chitosans were effective to delay spore germination, whereas yeast decreased apical fungal growth. PMID:18031804

Pacheco, Neith; Larralde-Corona, C Patricia; Sepulveda, Jose; Trombotto, Stéphan; Domard, Alain; Shirai, Keiko

2008-07-01

341

Use of chitosan in the treatment of obesity: evaluation of interaction with vitamin B2.  

PubMed

Obesity is a serious health problem and its prevalence has increased over the years. Studies have assessed the polysaccharide chitosan as anti-obesity supplement due to its ability to absorb fats. However, this property may cause the interaction of chitosan with essential substances for the proper functioning of the body, such as vitamins. In this context, the purpose of the present study was to evaluate interactions of the chitosan with vitamin B2. These interactions were evaluated in the absence and the presence of acid aqueous solution of chitosan using fluorescence and ultraviolet-visible absorption measurements of vitamin B2. Results showed that the rigid microenvironment generated by chitosan solution modifies the photophysics properties of vitamin B2. Thus, chitosan is able to eliminate vitamin B2 and the present study aims to warn of excessive loss of vitamins or other nutrients by the body during prolonged treatment with chitosan. PMID:21155669

Rodrigues, Máira Regina; Oliveira, Hueder Paulo M; Lacerda, Fábio Vieira

2011-05-01

342

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

343

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

344

Development of multifunctional chitosan beads for fluoride removal.  

PubMed

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

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

2009-08-15

345

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

346

Chitosan beads loaded with essential oils in cosmetic formulations.  

PubMed

The aim of this work is to evaluate the stability and release of chitosan beads loaded with volatile molecules of Mentha piperita essential oil (E.O.) in a cosmetic formulation. The ability of the beads to quickly release Mentha piperita E.O. during use of a cosmetic formulation such as a bath foam is also assessed. The chitosan beads were produced with three different chitosan dispersions gelled with two different gelling solutions: (a) a 10% solution of sodium hydroxide (NaOH) and (b) a 4% solution of sodium tripolyphosphate (TPP). A few properties of six bead samples loaded with Mentha piperita E.O. are assessed. The properties are morphology, size, swelling ability, encapsulation efficiency, stability in time, and fast release of Mentha piperita E.O. during the use phase of the cosmetic formulation. PMID:16832571

Anchisi, C; Meloni, M C; Maccioni, A M

2006-01-01

347

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

348

Study of polyelectrolyte complexes of chitosan and sulfoethyl cellulose  

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

349

Chitosan based edible films and coatings: a review.  

PubMed

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

Elsabee, Maher Z; Abdou, Entsar S

2013-05-01

350

Superhydrophobic chitosan-based coatings for textile processing  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

351

Alginate and Chitosan Gel Nanoparticles for Efficient Protein Entrapment  

NASA Astrophysics Data System (ADS)

Alginate and chitosan nanoparticles were synthesized by ionic gelation of the polymers in the presence of stabilizers (PEG 1500, PEG 6000, TWEEN 80). The stability of 210-240 nm Ca-alginate colloids is affected by nanoparticles ageing and by the presence of a stabilizer. The diameter of chitosan nanoparticles is in the range of 180 to 260 nm and depends on polymer concentration in the reaction mixture, its molecular weight, and stabilizer type. The nanoparticles efficiently entrap a model protein, bovine serum albumin, in the amount up to 0.24 mg per 1 mg of polysaccharide.

Masalova, O.; Kulikouskaya, V.; Shutava, T.; Agabekov, V.

352

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

353

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

PubMed

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

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

2010-12-01

354

Induction of Th1Type Immune Response by Chitosan Nanoparticles Containing Plasmid DNA Encoding House Dust Mite Allergen Der p 2 for Oral Vaccination in Mice  

Microsoft Academic Search

This study was to prepare the chitosan-pDer p 2 nanoparticles and to investigate the effect of chitosan-DNA nanoparticles on immune response in mice by oral delivery of chitosan-DNA nanoparticles. The nanoparticles were synthesized by complexing chitosan with plasmid DNA. The DNA was fully complexed into chitosan-DNA nanoparticles, suggesting a 100% encapsulation efficiency. Chitosan-DNA complex renders a significant protection of the

Guoping Li; Zhigang Liu; Bin Liao; Nanshan Zhong

2009-01-01

355

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

PubMed

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

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

2013-01-01

356

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

PubMed

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

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

2012-05-10

357

Polymeric Carriers for Gene Delivery: Chitosan and Poly(amidoamine) Dendrimers  

PubMed Central

Gene therapy is a potential medical solution that promises new treatments and may hold the cure for many different types of diseases and disorders of the human race. However, gene therapy is still a growing medical field and the technology is still in its infancy. The main challenge for gene therapy is to find safe and effective vectors that are able to deliver genes to the specific cells and get them to express inside the cells. Due to safety concerns, synthetic delivery systems, rather than viral vectors, are preferred for gene delivery and significant efforts have been focused on the development of this field. However, we are faced with problems like low gene transfer efficiency, cytotoxicity and lack of cell-targeting capability for these synthetic delivery systems. Over the years, we have seen a variety of new and effective polymers which have been designed and synthesized specifically for gene delivery. Moreover, various strategies that aimed at enhancing their physicochemical properties, improving transfection efficiency, reducing cytotoxicity as well as incorporating functional groups that offer better targetability and higher cellular uptake are established. Here, we look at two potential polymeric carriers, chitosan and poly(amidoamine) dendrimers, which have been widely reported for gene delivery. For chitosan, the interest arises from their availability, excellent non-cytotoxicity profile, biodegradability and ease of modification. For poly(amidoamine) dendrimers, the interest arises from their ease of synthesis with controlled structure and size, minimal cytotoxicity, biodegradability and high transfection efficiencies. The latest developments on these polymers for gene delivery will be the main focus of this article. PMID:20618156

Xu, Qingxing; Wang, Chi-Hwa; Pack, Daniel Wayne

2012-01-01

358

Coating electrospun chitosan nanofibers with polyelectrolyte multilayers using the polysaccharides heparin and N,N,N-trimethyl chitosan.  

PubMed

A new method is presented for functionalizing electrospun nanofibers with GAGs and growth factors by PEM deposition. Electrospun chitosan nanofibers, spun from trifluoroacetic acid and dichloromethane, were coated with PEMs, using the polysaccharides heparin and N,N,N-trimethyl chitosan. FGF-2 was adsorbed on the PEM-coated nanofibers. Nanofiber neutralization, PEM construction, and FGF-2 adsorption were monitored using FT-IR spectroscopy and X-ray photoelectron spectroscopy. Alcian blue staining was used to confirm the presence of heparin. SEM was used to study nanofiber morphology. PMID:20976723

Almodóvar, Jorge; Kipper, Matt J

2011-01-10

359

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

PubMed

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

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

2013-06-01

360

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

PubMed Central

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

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

2014-01-01

361

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

PubMed Central

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

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

2014-01-01

362

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

PubMed

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

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

2011-04-15

363

Synthesis of chitosan based nanoparticles and their in vitro evaluation against phytopathogenic fungi.  

PubMed

The main aim of present study was to prepare chitosan, chitosan-saponin and Cu-chitosan nanoparticles to evaluate their in vitro antifungal activities. Various nanoparticles were prepared using ionic gelation method by interaction of chitosan, sodium tripolyphosphate, saponin and Cu ions. Their particle size, polydispersity index, zeta potential and structures were confirmed by DLS, FTIR, TEM and SEM. The antifungal properties of nanoparticles against phytopathogenic fungi namely Alternaria alternata, Macrophomina phaseolina and Rhizoctonia solani were investigated at various concentrations ranging from 0.001 to 0.1%. Among the various formulations of nanoparticles, Cu-chitosan nanoparticles were found most effective at 0.1% concentration and showed 89.5, 63.0 and 60.1% growth inhibition of A. alternata, M. phaseolina and R. solani, respectively in in vitro model. At the same concentration, Cu-chitosan nanoparticles also showed maximum of 87.4% inhibition rate of spore germination of A. alternata. Chitosan nanoparticles showed the maximum growth inhibitory effects (87.6%) on in vitro mycelial growth of M. phaseolina at 0.1% concentration. From our study it is evident that chitosan based nanoparticles particularly chitosan and Cu-chitosan nanoparticles have tremendous potential for further field screening towards crop protection. PMID:24141067

Saharan, Vinod; Mehrotra, Akanksha; Khatik, Rajesh; Rawal, Pokhar; Sharma, S S; Pal, Ajay

2013-11-01

364

A study on antifungal activity of water-soluble chitosan against Macrophomina phaseolina.  

PubMed

The objective of this study was to evaluate antifungal effect of water-soluble chitosan (s-chitosan) on Macrophomina phaseolina (M. phaseolina) causing jute seedling infection and monitor the change in activity of released enzymes during infection. The minimum inhibitory concentration (MIC) of s-chitosan for M. phaseolina was found at 12.5g/l and s-chitosan exhibited fungistatic mode of action against this pathogen. The application of s-chitosan (12.5g/l) during infection of jute seedlings by M. phaseolina inhibited fungal infection and length of the seedlings was found almost similar to seedlings without infection. M. phaseolina infected jute seedlings showed length of 22mm over 10 days of incubation and it increased to 58mm in presence of s-chitosan (12.5g/l) during incubation for 10 days. TEM study indicated presence of hyphae in the cortical and epidermal cells of fungus infected jute seedlings indicating colonization by the fungus and it disappeared after treatment with s-chitosan. The changes in enzyme profiles of jute seedling during prevention of fungal infection using s-chitosan helped in proper understanding of mode of action of s-chitosan as antifungal agent. The activity of defense related enzymes like chitosanase and peroxidase in infected seedlings was observed to be enhanced after treatment with s-chitosan. PMID:24747381

Chatterjee, Sudipta; Chatterjee, Bishnu P; Guha, Arun K

2014-06-01

365

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

PubMed

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

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

2014-06-01

366

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

PubMed Central

The objective of this study was to determine whether chitosan (poly-?-1,4-glucosamine) and hydrolysates of chitosan can be used as novel preservatives in foods. Chitosan was hydrolyzed by using oxidative-reductive degradation, crude papaya latex, and lysozyme. Mild hydrolysis of chitosan resulted in improved microbial inactivation in saline and greater inhibition of growth of several spoilage yeasts in laboratory media, but highly degraded products of chitosan exhibited no antimicrobial activity. In pasteurized apple-elderflower juice stored at 7°C, addition of 0.3 g of chitosan per liter eliminated yeasts entirely for the duration of the experiment (13 days), while the total counts and the lactic acid bacterial counts increased at a slower rate than they increased in the control. Addition of 0.3 or 1.0 g of chitosan per kg had no effect on the microbial flora of houmous, a chickpea dip; in the presence of 5.0 g of chitosan per kg, bacterial growth but not yeast growth was substantially reduced compared with growth in control dip stored at 7°C for 6 days. Improved antimicrobial potency of chitosan hydrolysates like that observed in the saline and laboratory medium experiments was not observed in juice and dip experiments. We concluded that native chitosan has potential for use as a preservative in certain types of food but that the increase in antimicrobial activity that occurs following partial hydrolysis is too small to justify the extra processing involved. PMID:10618206

Rhoades, J.; Roller, S.

2000-01-01

367

Nanosized magnetofluorescent Fe 3O 4–curcumin conjugate for multimodal monitoring and drug targeting  

Microsoft Academic Search

Magnetic drug targeting, the targeting of a drug conjugated with a magnetic material under the action of external magnetic field constitutes an important drug delivery system. This paper describes the strategy to design a multifunctional, nanosized magnetofluorescent water-dispersible Fe3O4–curcumin conjugate and its multiple ability to label, target and treat the tumor cells. The conjugate possesses magnetic nano Fe3O4 core, chitosan

Lam Dai Tran; Nhung My T. Hoang; Trang Thu Mai; Hoang Vinh Tran; Ngoan Thi Nguyen; Thanh Dang Tran; Manh Hung Do; Qui Thi Nguyen; Dien Gia Pham; Thu Phuong Ha; Hong Van Le; Phuc Xuan Nguyen

2010-01-01

368

Utilization of chitosan as an antimicrobial agent for pasteurized palm sap (Borassus flabellifer Linn.) during storage.  

PubMed

The objective of this research was to assess the potential of chitosan for improvement the quality of pasteurized palm sap during storage. First, the effect of chitosan content on sensory attributes was investigated to select suitable concentration of chitosan for further study. Fresh palm sap was enriched with chitosan at various concentrations (0-2 g/L) and pasteurized at 80 °C for 10 min, consequently evaluated by consumers. It was found that samples added chitosan in the range of 0-1.00 g/L were considered acceptable. Thus, the addition chitosan in the concentration of 0-1.00 g/L was chosen for further study. The sample without chitosan addition was used as a control sample. Each selected sample was determined for their qualities during storage at 1 week interval. It was found that lightness and transmittance values of all samples tended to increase during storage. Lower PPO and invertase activity were observed in all chitosan-treated samples compared to control sample. Chitosan could minimize the loss of sucrose and the increase in glucose and fructose content during storage. In addition, an increase in chitosan concentration resulted in the increase in DPPH radical scavenging activity. Furthermore, the addition of chitosan could retard the development of microorganism during storage as demonstrated by lower microbial loads compared to control sample. It can be concluded that a combination of pasteurization with chitosan addition (0.50 g/L) and low temperature storage could preserve palm sap for approximately 6 weeks. Thus, the incorporation of chitosan in palm sap could be used as an alternative way to extend shelf life of pasteurized palm sap. PMID:25694681

Naknean, Phisut; Jutasukosol, Keawta; Mankit, Theerarat

2015-02-01

369

Abatement of Azo Dye from Wastewater Using Bimetal-Chitosan  

PubMed Central

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

Asgari, Ghorban; Farjadfard, Sima

2013-01-01

370

Cocatalyst effect in potassium persulfate initiated grafting onto chitosan  

Microsoft Academic Search

Methyl methacrylate and methyl acrylate were grafted onto chitosan by using potassium persulfate alone as redox initiator and in combination with MnCl2 and CuCl2, as inorganic, and both ammonium tartrate and oxalate as organic cocatalysts. The extent of grafting was found to depend mainly on the nature of the cocatalysts used.

J. Retuert; M. Yazdani-Pedram

1993-01-01

371

Chitosan-based mucoadhesive tablets for oral delivery of ibuprofen.  

PubMed

Chitosan and its half-acetylated derivative have been compared as excipients in mucoadhesive tablets containing ibuprofen. Initially the powder formulations containing the polymers and the drug were prepared by either co-spray drying or physical co-grinding. Polymer-drug interactions and the degree of drug crystallinity in these formulations were assessed by infrared spectroscopy and differential scanning calorimetry. Tablets were prepared and their swelling and dissolution properties were studied in media of various pHs. Mucoadhesive properties of ibuprofen-loaded and drug-free tablets were evaluated by analysing their detachment from pig gastric mucosa over a range of pHs. Greater polymer-drug interactions were seen for spray-dried particles compared to co-ground samples and drug loading into chitosan-based microparticles (41%) was greater than the corresponding half-acetylated samples (32%). Swelling and drug release was greater with the half-acetylated chitosan tablets than tablets containing the parent polymer and both tablets were mucoadhesive, the extent of which was dependent on substrate pH. The results illustrate the potential sustained drug delivery benefits of both chitosan and its half-acetylated derivative as mucoadhesive tablet excipients. PMID:22842627

Sogias, Ioannis A; Williams, Adrian C; Khutoryanskiy, Vitaliy V

2012-10-15

372

Vanadium (IV) sorption by chitosan: Kinetics and equilibrium  

Microsoft Academic Search

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

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

1996-01-01

373

Physiology of microbial degradation of chitin and chitosan  

Microsoft Academic Search

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

Graham W. Gooday

1990-01-01

374

Tympanic membrane regeneration using a water-soluble chitosan patch.  

PubMed

Chronic otitis media or tympanic membrane (TM) perforation is one of the most common otologic diseases. Surgical tympanoplasty remains the best treatment option despite the fact that paper patches are frequently used. Although paper patches are not biocompatible or effective, tympanoplasty is an expensive, complex surgery. Tissue engineering techniques offer a new treatment strategy for TM regeneration. In this study, novel tissue-engineered artificial eardrums were fabricated from water-soluble chitosan, which is known to be a good wound-healing biomaterial. The characteristics, cytotoxicity, and healing effects of several water-soluble chitosan patches (WSCPs) made using various concentrations of water-soluble chitosan and glycerol were investigated. The optimal WSCP was fabricated with 3% water-soluble chitosan and 3% glycerol, and it had a thickness of about 35 mum, a tensile strength of 7 MPa, a percent elongation of 101%, a hydrophilic surface, and no cytotoxicity. In vivo studies showed that the WSCPs were more effective than spontaneous healing for the repair of traumatic TM perforations. The healed TMs to which WSCPs were applied had a much higher density of collagen fibers and a better lamina propria layer structure than spontaneously healed TMs. PMID:19691425

Kim, Jang Ho; Choi, Seong Jun; Park, Jung-Sub; Lim, Ki Taek; Choung, Pill-Hoon; Kim, Seung Won; Lee, Jong Bin; Chung, Jong Hoon; Choung, Yun-Hoon

2010-01-01

375

Design and development of nevirapine loaded surfactant free chitosan microemulsion.  

PubMed

Emulsification of liquid paraffin oil in aqueous solutions of chitosan without adding any additional surfactant is studied. The main objective of this study was to evaluate the dispersion of castor oil in aqueous phase in the presence of chitosan, and how this polymer promotes the stability of the obtained emulsions. Nevertheless, chitosan promotes emulsion production by increasing the matrix viscosity and provides stabilization of the oil-water interface by forming a dense hydrophilic polyelectrolytic brush on the water side of interface, which presents a significant barrier for coalescence--both steric and electrostatic. Chitosan stabilizes the emulsion mainly by the steric effect. These steric effects generate Van der Waals repulsion forces when two particles are too close. After loading with antiviral drug nevirapine, these emulsions were characterized in terms of phase contrast microscopy, hot stage microscopy, fluorescence microscopy, particle size, zeta potential, viscosity, entrapment efficiency and release studies using dialysis bag method. The prepared emulsions were stable in terms of mean globule size, change in drug content and retain they cationicity. The formulated emulsions are a promising carrier for nevirapine and other lipophilic drugs. PMID:22125965

Bajaj, Himani; Bisht, Seema; Yadav, Mayank; Singh, Vinod; Singh, Mamta

2011-01-01

376

Formulation and evaluation of chitosan solid lipid nanoparticles of carbamazepine  

PubMed Central

The present work aims at preparing aqueous suspension of Solid lipid Nanoparticles containing Chitosan (CT) which is a biopolymer that exhibits a number of interesting properties which include controlled drug delivery. Carbamezapine (CBZ) is a lipophilic drug which shows it antiepileptic activity by inactivating sodium channels. The solid lipid Nanoparticles (SLN) of Chitosan-CBZ were prepared by using solvent injection method using ethanol as organic solvent. The prepared SLN formulations exhibited high encapsulation efficiency, high physical stability. The drug incorporated SLNs have demonstrated that the controlled release patterns of the drug for prolonged period. The prepared SLNs were characterized for surface morphology by SEM analysis, entrapment efficiency, zeta potential, FTIR, DSC and In-vitro diffusion studies. The hydrodynamic mean diameter and zeta potential were 168.7 ±1.8?nm and ?28.9 ±2.0?mV for SLN-chitosan-CBZ respectively. Therefore chitosan-SLN can be good candidates to encapsulate CBZ and to increase its therapeutic efficacy in the treatment of Epilepsy. PMID:22695222

2012-01-01

377

Atomic force microscopy of gastric mucin and chitosan mucoadhesive systems.  

PubMed Central

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

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

2000-01-01

378

Virus adsorption of water-stable quaternized chitosan nanofibers.  

PubMed

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

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

2014-03-31

379

Chitosan and its derivatives for tissue engineering applications  

Microsoft Academic Search

Tissue engineering is an important therapeutic strategy for present and future medicine. Recently, functional biomaterial researches have been directed towards the development of improved scaffolds for regenerative medicine. Chitosan is a natural polymer from renewable resources, obtained from shell of shellfish, and the wastes of the seafood industry. It has novel properties such as biocompatibility, biodegradability, antibacterial, and wound-healing activity.

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

2008-01-01

380

Rheology of highly swollen chitosan\\/polyacrylate hydrogels  

Microsoft Academic Search

Recently we reported on chitosan hydrogel systems having excellent laser damage resistance. The measured laser damage threshold (LDT) was better than BK7 glass and quartz, commonly used inorganic optical materials, and 20 to 35 times higher than commercial PMMA, a popular polymer optical material. In this study, we continue our investigation of the phase transition behavior of water within the

H. Jianga; T. J. Bunninga; Wright Patterson AFB

381

Typical physicochemical behaviors of chitosan in aqueous solution.  

PubMed

Physicochemical properties of a homogeneous series of chitosans with different degrees of acetylation and almost the same degree of polymerization were investigated in an ammonium acetate buffer. Techniques such as interferometry, static light scattering (in batch or coupled on line with a chromatographic system), and viscometry were processed. All of the results agree with a unique law of behavior only depending on the degree of acetylation of the polymer. Indeed, values of the refractive index increment, radius of gyration, second viral coefficient, and intrinsic viscosity are decreasing in the same way as DA is increasing. Three distinct domains of DA were defined and correlated to the different behaviors of chitosans: (i) a polyeletrolyte domain for DA below 20%; (ii) a transition domain between DA = 20% and 50% where chitosan loses its hydrophilicity; (iii) a hydrophobic domain for DAs over 50% where polymer associations can arise. Conformations of chitosan chains were studied by the calculations of the persistence lengths (L(p)). The average value was found to be close to 5 nm, in agreement with the wormlike chain model, but no significant variation of L(p) with the degree of acetylation was noticed. PMID:12741780

Schatz, Christophe; Viton, Christophe; Delair, Thierry; Pichot, Christian; Domard, Alain

2003-01-01

382

Rheological characterisation of thermogelling chitosan/glycerol-phosphate solutions  

E-print Network

can be neutralised up to physiological pH (,7.2) using b-glycerol phosphate without creating immediate and other physicochemical conditions including control of hydrophobic interactions and hydrogen bonding and wide scope of use. Chitosan has been recommended as an appropriate material for many purposes

Buschmann, Michael

383

Influence of grape pomace extract incorporation on chitosan films properties.  

PubMed

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

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

2014-11-26

384

Uptake and cytotoxicity of chitosan nanoparticles in human liver cells  

SciTech Connect

Despite extensive research into the biomedical and pharmaceutical applications of nanoparticles, and the liver being the main detoxifying organ in the human body, there are limited studies which delineate the hepatotoxicity of nanoparticles. This paper reports on the biological interactions between liver cells and chitosan nanoparticles, which have been widely recognised as biocompatible. Using the MTT assay, human liver cells were shown to tolerate up to 4 h of exposure to 0.5% w/v of chitosan nanoparticles (18 {+-} 1 nm, 7.5 {+-} 1.0 mV in culture medium). At nanoparticle concentrations above 0.5% w/v, cell membrane integrity was compromised as evidenced by leakage of alanine transaminase into the extracellular milieu, and there was a dose-dependent increase in CYP3A4 enzyme activity. Uptake of chitosan nanoparticles into the cell nucleus was observed by confocal microscopic analysis after 4 h exposure with 1% w/v of chitosan nanoparticles. Electron micrographs further suggest necrotic or autophagic cell death, possibly caused by cell membrane damage and resultant enzyme leakage.

Loh, Jing Wen [Laboratory for Drug Delivery, Pharmacy, University of Western Australia, 35 Stirling Hwy, Crawley, 6009 (Australia); Yeoh, George [School of Biomedical, Biomolecular and Chemical Sciences, University of Western Australia, 35 Stirling Hwy, Crawley, 6009 (Australia); Centre for Medical Research, Western Australian Institute for Medical Research, Nedlands, WA 6009 (Australia); Saunders, Martin [Centre for Microscopy, Characterisation and Analysis, University of Western Australia, 35 Stirling Hwy, Crawley, 6009 (Australia); Lim, Lee-Yong, E-mail: limly@cyllene.uwa.edu.a [Laboratory for Drug Delivery, Pharmacy, University of Western Australia, 35 Stirling Hwy, Crawley, 6009 (Australia); School of Biomedical, Biomolecular and Chemical Sciences, University of Western Australia, 35 Stirling Hwy, Crawley, 6009 (Australia)

2010-12-01

385

Enriched fluoride sorption using alumina/chitosan composite.  

PubMed

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

Viswanathan, Natrayasamy; Meenakshi, S

2010-06-15

386

Author's personal copy Precise derivatization of structurally distinct chitosans  

E-print Network

Author's personal copy Precise derivatization of structurally distinct chitosans with rhodamine B of deacetylation; Molecular weight; Rhodamine B isothiocyanate; Rhodamine B; Extinction coefficient; Degree isothiocyanate Odette Ma a,1 , Marc Lavertu a,1 , Jun Sun b , Sophie Nguyen c,d , Michael D. Buschmann a

Buschmann, Michael

387

Phase-separated chitosan–fibrin microbeads for cell delivery  

PubMed Central

Matrix-enhanced delivery of cells is a promising approach to improving current cell therapies. Our objective was to create cell-laden composite microbeads that combine the attractive features of the natural polymers chitosan and fibrin. Liquid polydimethylsiloxane was used to emulsify a chitosan–fibrinogen solution containing suspended human fibroblast cells, followed by initiation of thrombin-mediated polymerization of fibrin and thermal/pH-mediated gelation of chitosan. Chitosan/fibrin weight percent (wt%) ratios of 100/0, 75/25, 50/50 and 25/75 were investigated. Microbead diameters ranged from 275 ± 99 ?m to 38 ± 10 ?m using impeller speeds from 600 to 1400 rpm. Fibroblasts remained viable on day 1 post-fabrication in all matrices, but cell viability was markedly higher in high-fibrin microbeads by day 8 post-fabrication. Cell spreading and interaction with the extracellular matrix was also markedly increased in high-fibrin matrices. Such composite microbeads containing viable entrapped cells have potential for minimally invasive delivery of cells for a variety of tissue repair applications. PMID:21736519

Chen, Zhewei; Wang, Limin; Stegemann, Jan P.

2011-01-01

388

Phase-separated chitosan-fibrin microbeads for cell delivery.  

PubMed

Matrix-enhanced delivery of cells is a promising approach to improving current cell therapies. Our objective was to create cell-laden composite microbeads that combine the attractive features of the natural polymers chitosan and fibrin. Liquid polydimethylsiloxane was used to emulsify a chitosan-fibrinogen solution containing suspended human fibroblast cells, followed by initiation of thrombin-mediated polymerization of fibrin and thermal/pH-mediated gelation of chitosan. Chitosan/fibrin weight percent (wt%) ratios of 100/0, 75/25, 50/50 and 25/75 were investigated. Microbead diameters ranged from 275?±?99?µm to 38?±?10?µm using impeller speeds from 600 to 1400?rpm. Fibroblasts remained viable on day 1 post-fabrication in all matrices, but cell viability was markedly higher in high-fibrin microbeads by day 8 post-fabrication. Cell spreading and interaction with the extracellular matrix was also markedly increased in high-fibrin matrices. Such composite microbeads containing viable entrapped cells have potential for minimally invasive delivery of cells for a variety of tissue repair applications. PMID:21736519

Chen, Zhewei; Wang, Limin; Stegemann, Jan P

2011-01-01

389

Chitosan as template for the synthesis of ceria nanoparticles  

SciTech Connect

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

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

2011-11-15

390

Chitosan and its antimicrobial potential – a critical literature survey  

PubMed Central

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

Raafat, Dina; Sahl, Hans?Georg

2009-01-01

391

Physichemical property and morphology of 5-fluorouracil loaded chitosan nanoparticles  

Microsoft Academic Search

fluorouracil (5-FU), a hydrophilic anticancer drug, was successfully encapsulated into biodegradable chitosan (CS) to form CS\\/5-FU nanoparticles (NPs) by ionic crosslinking technology. The surface morphology of the pure CS NPs and 5- FU loaded NPs was investigated by scanning electron microscopy (SEM); the interaction between CS and 5- florouracil (5-FU) was studied by Fourier transform infrared spectrometer (FTIR); the physical

Puwang Li; Yichao Wang; Zheng Peng; Mary F. She; Lingxue Kong

2010-01-01

392

A chitosan induced 9-lipoxygenase in Adelostemma gracillimum seedlings.  

PubMed

Oxylipins generated by the lipoxygenase (LOX) pathway play an important role in plant defense against biotic and abiotic stress. In chitosan-treated Adelostemma gracillimum seedlings, obvious accumulation of 9-LOX-derived oxylipins, namely 9,10,11-trihydroxy-12-octadecenoic acid, was detected. Using degenerate primers, a LOX-specific fragment putatively encoding LOX was obtained by RT-PCR, and a 2.9-kb full-length cDNA named AgLOX1 was isolated by RACE from chitosan-induced A. gracillimum seedlings. Genomic Southern analysis implied that there was only one copy of AgLOX1 in the A. gracillimum genome. AgLOX1 was expressed in Escherichia coli and the recombinant protein was partially purified. The enzyme converted linoleic and linolenic acids almost exclusively to their 9-hydroperoxides. AgLOX1 encoded a 9-lipoxygenase. Northern blot analysis indicated that chitosan-induced AgLOX1 transcript accumulation peaked at 8 h after initiation of treatment, whereas trihydroxy derivatives accumulation was highest at 24 h after elicitation. Results showed that chitosan-induced AgLOX1 encoded a 9-lipoxygenase potentially involved in the defense response through 9-LOX pathway leading to biosynthesis of antimicrobial compounds in A. gracillimum seedlings. PMID:22312270

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

2012-01-01

393

Recent Advances in Drugs and Prodrugs Design of Chitosan  

Microsoft Academic Search

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

J. Vinsova; E. Vavrikova

394

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

E-print Network

One-Step Analysis of DNA/Chitosan Complexes by Field-Flow Fractionation Reveals Particle Size with chitosan was analyzed by asymmetrical flow field flow fractionation (AF4) with online UV particles.2 Asym- metrical flow field-flow fractionation (AF4), an analytical separation technique in which

Buschmann, Michael

395

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

PubMed

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

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

2014-02-15

396

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

PubMed

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

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

2014-12-19

397

Chitosan based nanocarriers for indomethacin ocular delivery.  

PubMed

Two different chitosan (CS) nanocarriers namely nanoparticles and nanoemulsion were developed to prolong Indomethacin (IM) precorneal residence time and to improve its ocular bioavailability the main limitations in its management of post-operative inflammation and intraocular irritation after cataract extraction. CS-nanoparticles were developed by modified ionic gelation of CS with tripolyphosphate while nanoemulsion was prepared by spontaneous emulsification technique. Transmission electron microscopy revealed regular well-identified spherical shape. The nanoparticles had a mean size of 280 nm, a zeta potential of + 17 mV and high loading efficiency of 84.8 % while the mean size of nanoemulsion was affected by the nature of the surfactant used and varies between 220-690 nm. In vitro release studies, performed under sink conditions, revealed small initial burst release during the first hour followed by slow gradual drug release of 76 and 86% from nanoparticles and nanoemulsion respectively during a 24 h period. In vivo studies and histopathological examination revealed that eyes of rabbits treated with nanoemulsion showed clearer healing of corneal chemical ulcer with moderate effective inhibition of polymorph nuclear leukocytic infiltration (PMNLs) compared with nanoparticles preparation. Moreover, following topical instillation of CS-nanoemulsion to rabbits, it was possible to achieve therapeutic concentration of IM in the cornea through out the duration of the study and fairly high IM level in inner ocular structure, aqueous humor. These levels were significantly higher than those obtained following instillation of IM solution. Therefore, CS nanocarriers developed in this study were able to contact intimately with the cornea providing slow gradual IM release with long-term drug level thereby increasing delivery to both external and internal ocular tissues. PMID:18787795

Badawi, Alia A; El-Laithy, Hanan M; El Qidra, Riad K; El Mofty, Hala; El dally, Mohamed

2008-08-01

398

Imino-chitosan biopolymeric films. Obtaining, self-assembling, surface and antimicrobial properties.  

PubMed

The paper reports the preparation of twelve imino-chitosan biopolymer films by acid condensation of the amino groups of chitosan with various aldehydes, in aqueous medium, followed by slow water removal. FTIR spectroscopy has shown drastic conformation changes of chitosan macromolecular chains—from a stiff coil to a straight one, while wide angle X-ray diffraction evidenced a layered morphology of the biopolymer films. Contact angle and surface free energy determination indicated a higher biocompatibility of the new biopolymers as compared to the chitosan parent, while the microbiological screening demonstrated their self-defense properties against common and virulent pathogen agents. It was concluded that the reversibility of imine forming promotes the self-assembling of imino-chitosan biopolymer films into a lamellar morphology and, on the other hand, the slow release of the antimicrobial aldehyde in the microbiological culture. The obtained results demonstrate that chitosan polyamine is a challenging workbench to functional biodynamic materials. PMID:25498698

Marin, Luminita; Ailincai, Daniela; Mares, Mihai; Paslaru, Elena; Cristea, Mariana; Nica, Valentin; Simionescu, Bogdan C

2015-03-01

399

Effect of deacetylation degree in chitosan composite membranes on pervaporation performance  

SciTech Connect

The effect of the degree of deacetylation in chitosan composite membranes on their pervaporation performance for ethanol dehydration was investigated. The degree of deacetylation of chitosans was measured by using an infrared spectroscopic method and elemental analysis. The chitosan composite membranes were prepared by coating a chitosan solution onto a microporous polyethersulfone membrane with 3--7 nm pore sizes. Then the surface of the top layer (chitosan) of well-dried membranes was crosslinked with sulfuric acid, and pervaporation experiments for binary mixtures (water-ethanol) were carried out at various conditions. In the case of a chitosan membrane with a high degree of deacetylation, the flux increases while the separation factor decreases compared with membranes with a low degree of deacetylation.

Lee, Y.M.; Park, H.B.; Nam, S.Y. [Hanyang Univ., Seoul (Korea, Republic of); Won, J.M.; Kim, H. [Research and Development Management Center for Energy, Seoul (Korea, Republic of)

1998-06-01

400

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

401

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

PubMed Central

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

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

2011-01-01

402

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

PubMed

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

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

2014-01-30

403

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

PubMed

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

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

2014-02-01

404

Collagen/chitosan film containing biotinylated glycol chitosan nanoparticles for localized drug delivery.  

PubMed

The objective of this study was to design a drug delivery system consisting of biotinylated cholesterol-modified glycol chitosan (Bio-CHGC) nanoparticles and fish collagen/chitosan (Col/Ch) film for localized chemotherapy. Bio-CHGC was synthesized, and then its self-assembled nanoparticles were prepared by probe sonication. Doxorubicin (DOX)-loaded Bio-CHGC (DBC) nanoparticles prepared by dialysis had spherical shape, and their sizes were in the range of 330-397nm. Col/Ch/DBC nanoparticle films were fabricated by freeze-drying. SEM showed that the DBC nanoparticles were uniformly distributed into the films, and the films retained their structural integrity. A higher degradation and swelling rate of the drug films led to a higher diffusion rate of the nanoparticles from the films, resulting in an increase in the drug release from nanoparticles. The release of DOX from the films or Bio-CHGC nanoparticles was sensitive to the pH value of the release medium. In addition, the DOX release ratio of the drug films was lower than that of the nanoparticles alone, suggesting that the drug films had a double-sustained effect on the drug release. MTT assay implied that the DBC nanoparticle film showed a higher inhibitory ratio than the film containing nanoparticles without biotin, indicating that biotin moieties in the nanoparticles played an important role in exerting a cytotoxic effect. These data demonstrate that Col/Ch/DBC nanoparticle film has the potential to be used as a localized delivery system for hydrophobic antitumor drugs. PMID:25784300

Chen, Ming-Mao; Huang, Yu-Qing; Cao, Huan; Liu, Yan; Guo, Hao; Chen, Lillian S; Wang, Jian-Hua; Zhang, Qi-Qing

2015-04-01

405

Cytotoxicity of monodispersed chitosan nanoparticles against the Caco-2 cells  

SciTech Connect

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

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

2012-08-01

406

Viscoelastic properties of phosphoric and oxalic acid-based chitosan hydrogels  

Microsoft Academic Search

In a previous work, we have shown that chitosan true physical gelation occurs in some organic and inorganic acids (Hamdine et al. 2004). Two systems presenting similar gelation mechanisms were characterized furthermore in order to investigate the sol–gel transition: the chitosan–phosphoric acid and the chitosan–oxalic acid systems. By performing rheological measurements in the framework of linear viscoelasticity, we have investigated the

Mélina Hamdine; Marie-Claude Heuzey; André Bégin

2006-01-01

407

Preparation and characterization of water-soluble chitin and chitosan derivatives  

Microsoft Academic Search

Chitosan was modified with poly(ethylene glycol)-aldehyde (PEG-aldehyde) of various molecular weights under the various molar ratios of PEG-aldehyde to chitosan. Then the prepared chitosan-PEG hybrid was converted to chitin-PEG hybrid by the acetylation with acetic anhydride. The solubility of various derivatives was investigated in three buffers of various pH. Some of these derivatives were soluble in 0.01 M phosphate buffer

Masatoshi Sugimoto; Minoru Morimoto; Hitoshi Sashiwa; Hiroyuki Saimoto; Yoshihiro Shigemasa

1998-01-01

408

Pore structure of gel chitosan membranes. III. Pressuredriven mass transport measurements  

Microsoft Academic Search

The capillary pore model of water-swollen gels was used to interpret pressure-driven mass transport properties of gel chitosan membranes. Pure water hydraulic permeability coefficients, Lp, and rejection coefficients, R, of 13 solutes ranging in molecular radius from 2.4 Å (methanol) to 16 Å (polyethylene glycol 6000) were measured for an untreated chitosan membrane, for two chitosan membranes crosslinked with glutaraldehyde

Barbara Krajewska

1996-01-01

409

Electrochemical thiocholine inhibition sensor based on biocatalytic growth of Au nanoparticles using chitosan as template  

Microsoft Academic Search

A simple strategy for the design of an electrochemical sensor based on enzyme-induced growth of gold nanoparticles (AuNPs) without adding gold nano-seeds was proposed with acetylcholinesterase (AChE) as a model. Owing to the excellent biocompatibility of chitosan film for the subsequent assembly of biological molecules, chitosan film was first electrochemically deposited on Au electrode surface from a mildly acidic chitosan

Dan Du; Jiawang Ding; Jie Cai; Aidong Zhang

2007-01-01

410

RF hydrazine plasma modification of chitosan for antibacterial activity and nanofiber applications  

Microsoft Academic Search

Chitosan nano powders were modified using RF hydrazine plasma produced at low pressure (26.66Pa) with 13.56MHz frequency at a power of 100W for 30min. Characterization and investigation of the properties of plasma-modified chitosan (PMCh) and non-modified chitosan (Ch) were carried out using an optical monochromator, FTIR, florescence analysis, TGA, SEM, and X-ray techniques. FTIR spectra of PMCh indicated a band

Aysegul Uygun; Melek Kiristi; Lutfi Oksuz; Sorin Manolache; Seyhan Ulusoy