Chitosan Oligomers Research Articles

Multifunctional Hybrid Materials From Poly(3‐Hydroxybutyrate), TiO2 Nanoparticles, and Chitosan Oligomers by Combining Electrospinning/Electrospraying and Impregnation

Several types of fibrous material containing poly(3-hydroxybutyrate) (PHB), nanosized TiO2 -anatase (nanoTiO2 ), and chitosan oligomers are prepared by combining the electrospinning, electrospraying, and impregnation techniques. Simultaneous electrospinning/electrospraying provides uniform distribution of electrosprayed nanoTiO2 along the PHB fibers and throughout the mat. Hybrid materials of different design manifest excellent photocatalytic activity, even after repeated use. They exhibit high bactericidal activity against Escherichia coli. In addition, the fibrous scaffolds are compatible with human mesenchymal stem cells and provide a favorable environment for their development.

Anti-biofouling 3D porous systems: the blend effect of oxazoline-based oligomers on chitosan scaffolds

The production, characterization and anti-biofouling activity of 3D porous scaffolds combining different blends of chitosan and oxazoline-based antimicrobial oligomers is reported. The incorporation of ammonium quaternized oligo(2-oxazoline)s into the composition of the scaffold enhances the stability of the chitosan scaffold under physiological conditions as well as its ability to repel protein adsorption. The blended scaffolds showed mean pore sizes in the range of 18–32 μm, a good pore interconnectivity and high porosity, as well as a large surface area, ultimate key features for anti-biofouling applications. Bovine serum albumin (BSA) adhesion profiles showed that the composition of the scaffolds plays a critical role in the chitosan–oligooxazoline system. Oligobisoxazoline-enriched scaffolds (20% w/w, CB8020) decreased protein adsorption (BSA) by up to 70%. Moreover, 1 mg of CB8020 was able to kill 99.9% of Escherichia coli cells upon contact, demonstrating its potential as promising material for production of tailored non-fouling 3D structures to be used in the construction of novel devices with applications in the biomedical field and water treatment processes.

In situ continuous growth formation of synthetic biominerals

Continuous self-assembled growth of both the organic and inorganic components of materials with nacre-like structure is achieved upon mineralisation of chitin and chitosan scaffolds using a combined soaking method and the inclusion of poly(acrylic acid) and chitosan oligomers as additives.

Fabrication of Chitosan-Poly(ethylene glycol) Hybrid Hydrogel Microparticles via Replica Molding and Its Application toward Facile Conjugation of Biomolecules

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

Computer modeling of chitosan adsorption on a carbon nanotube

Molecular dynamics (MD) simulation results for the adsorption process of chitosan oligomer on a carbon nanotube (CNT) are presented. An ab initio DFT calculation is performed to obtain the optimal geometric parameters and charge distribution in chitosan. Then by means of classic molecular dynamics the binding energy of a chitosan molecule with CNT calculated. It is found that the character of the interaction between a chitosan molecule and CNT is non-specific.

Cellular uptake of DNA–chitosan nanoparticles: The role of clathrin- and caveolae-mediated pathways

The success of gene therapy depends on efficient delivery of DNA and requires a vector. A promising non-viral vector is chitosan. We tailored chitosan to optimize it for transfection by synthesizing self-branched and trisaccharide-substituted chitosan oligomers (SBTCO), which show superior transfection efficacy compared with linear chitosan (LCO). The aim of the work was to compare the cellular uptake and endocytic pathways of polyplexes formed by LCO and SBTCO. Both polyplexes were taken up by the majority of the cells, but the uptake of LCO was lower than SBTCO polyplexes. LCO polyplexes were internalized through both clathrin-dependent and clathrin-independent pathways, whereas SBTCO polyplexes were primarily taken up by clathrin-independent endocytosis. The different level of cellular uptake and the distinct endocytic pathways, may explain the difference in transfection efficacy. This was supported by the observation that photochemical internalization increased the transfection by LCO polyplexes considerably, whereas no effect on transfection was found for SBTCO polyplexes.

Purification, characterization, and action mode of a chitosanase from Streptomyces roseolus induced by chitin

Chitosanase (EC3.2.1.132) catalyzes the hydrolysis of β-1,4-glycosidic bonds in chitosan, converting it into chitooligosaccharides, which exhibit versatile application potentials in food, pharmaceutical, and agricultural areas. In this paper we present a new inducible chitosanase, isolated, and purified from a bacterial culture medium of Streptomyces roseolus DH by precipitation with ammonium sulfate and combined column chromatographies. The SDS–PAGE results show its molecular mass is around 41kDa, with a purity of more than 95%. The purified chitosanase exhibits optimum activity at 50°C, pH 5.0. It is stable between 30 and 60°C and at pH values between 5 and 7. It shows the highest activity towards colloidal chitosan and breaks down glycol chitosan and glycol chitin weakly. The enzyme is significantly inhibited by Cu2+, Co2+, Mn2+, Zn2+, and EDTA, but slightly activated by Mg2+. Further action mode analysis based on chitosan oligomers and a polymer reveals that the chitosanase could split chitooligosaccharides with degree of polymerization (DP) >4 and chitosan in an endolytic manner. The resultant hydrolytes are mainly chitotrisaccharides, indicating it is suitable for the uniform bioconversion of chitosan and its derivatives with high efficiency.

다이옥신계 TCDD(2,3,7,8-Tetrachlorodibenzo-p-dioxin)에 노출된 흰쥐의 지질대사 및 면역관련 인자에 대하여 키토산 올리고머의 분자량별 섭취효과

다이옥신계 TCDD에 노출된 흰쥐의 지질대사 및 면역관련 인자에 대하여 키토산 올리고머의 분자량에 따른 섭취효과를 알아보기 위해 Sprague-Dawley rat(수컷, 6주령)를 이용하여 TCDD를 40 μg/kg BW로 복강 내 주입하고 키토산 올리고머 분자량을 1000 이하, 1000~3000 및 5000~10000으로 수준을 달리하여 4% 첨가하고 3주간 실험하였다. 실험 동물의 장기의 무게에서 간의 상대중량은 TCDD 투여군에서 모두 유의적으로 높았다. 뇌와 고환의 상대중량은 대조군과 TCDD 투여군에 비하여 TCDD 투여와 함께 키토산 올리고머를 섭취한 군에서 모두 현저히 증가하였다. 흉선의 상대 중량은 대조군에 비하여 TCDD 투여군에서 모두 약 1/4 정도로 감소되었다. 혈액성분에서 적혈구의 수는 TCDD 투여에 의한 감소가 TCDD 투여와 함께 키토산 올리고머를 섭취한 군 모두에서 대조군 수준으로 증가되었고, 백혈구의 수와 헤모글로빈 및 헤마토크리트값은 TCDD 투여에 의한 감소가 TCDD 투여와 함께 키토산 올리고머의 분자량이 1000이하인 것(COST)과 5000~10000인 것을 섭취한 군(COLT)에서 회복되는 경향을 보였다. 간 기능에 지표가 되는 효소인 혈청 GOT와 ALP는 대조군에 비하여 TCDD 투여군 모두에서 높은 경향을 보였다. 혈청 총콜레스테롤 및 HDL-콜레스테롤함량은 TCDD 투여에 의한 증가가 TCDD 투여와 함께 키토산 올리고머 분자량이 5000~10000인 것을 섭취한 군(COLT)에서 유의적으로 감소되어 콜레스테롤 억제효과가 나타났다. 간 지질에서는 총 지질과 콜레스테롤 및 중성지방이 유사한 경향으로 대조군에 비하여 TCDD 단독투여 군에서 현저한 증가를 보여 지질축적이 되었는데 TCDD 투여와 함께 키토산 올리고머를 섭취한 군들에서 현저한 지질 억제효과를 내었다. 특히 TCDD투여와 함께 분자량 1000이하의 키토산 올리고머를 섭취한 군(COST)이 TCDD 단독 투여 군에 비하여 간 콜레스테롤을 2/3 정도로, 간 중성지방을 1/2 정도로 뚜렷이 억제하였다. 변 중의 총 지질과 콜레스테롤함량은 TCDD 투여로 증가되는 경향이었고 TCDD 투여와 함께 키토산 올리고머 첨가한 군들에서는 TCDD군보다 대체로 낮은 경향이었다. 담즙산 배설은 대조군에 비하여 TCDD 투여군 모두에서 현저하게 낮았다. 간의 현미경적 관찰에서는 TCDD 투여에 의한 간세포의 지방구 침윤과 세포크기의 다양성, 간세포의 과염 색상과 공포변성이 TCDD 투여와 함께 키토산 올리고머를 섭취한 군 모두에서 현저하게 회복되었다. 혈청의 면역인자인 IgA와 IgM의 농도에서는 대조군과 TCDD 단독투여 군보다 TCDD 투여와 함께 키토산 올리고머의 분자량 5000~10000인 것을 섭취한 군(COLT)이 유의적으로 높은 농도를 나타내었다. 이와 같은 결과로 키토산 올리고머의 분자량이 1000 이하인 것은 혈구수의 회복과 간 지질억제에 효과적이었고, 분자량이 5000~10000인 것은 혈구수의 회복과 함께 혈청 콜레스테롤 저하 및 면역인자들 수준을 증가시키는 경향이 있었다. 특히 간의 조직병변이 키토산 올리고머 식이에 의해 정상으로 회복되는 경향을 관찰할 수 있었다. 그런데 키토산 올리고머의 분자량별 효과에 대하여는 앞으로 더 많은 연구가 필요한 것으로 사료된다.

<sup>1</sup>H-NMR Analysis of Degree of Substitution in N,O-Carboxymethyl Chitosans from Various Chitosan Sources and Types

N,O-Carboxymethyl chitosans were synthesized by the reaction between shrimp, crab and squid chitosans with monochloroacetic acid under basic conditions at 50°C. The mole ratio of reactants was obtained from various reaction conditions of shrimp chitosan polymer and oligomer types. The mole ratio 1:12:6 of chitosan:sodium hydroxide:monochloroacetic acid was used for preparing carboxymethyl of chitosan polymer types while carboxymethyl of chitosan oligomer types were used the mole ratio 1:6:3 of chitosan:sodium hydroxide:monochloroacetic acid. The chemical structure was analyzed by fourier transformed infrared spectroscopy (FT-IR) and proton nuclear magnatic resonance spectroscopy (1H-NMR). The FT-IR was used for confirm the insertion of carboxymethyl group on chitosan molecules. The 1H-NMR was used for determining the degree of substitution (DS) of carboxymethylation at hydroxyl and amino sites of chitosans. Carboxymethyl chitosan samples had the total DS of carboxymethylation ranging from 1.0-2.2. The highest of DS of carboxymethylation was from shrimp chitosan oligomer type.

New polyelectrolyte complex of chitosan: Preparation, characterization, and application as a biocontrol agent carrier

In this study, a novel water-insoluble polyelectrolyte complex between chitosan and poly(acrylic acid- co-maleic acid) was prepared and characterized. The chitosan used (M̅v = 23,000–60,000 g/mol) formed water-insoluble polyelectrolyte complexes at pH 2.2–4.8 and water-soluble chitosan oligomers (M̅v = 2,700 g/mol) at pH 2.2–7.4. The polyelectrolyte complexes formed were used in the preparation of novel carriers for a Trichoderma spp. biocontrol agent. Three types of beads were prepared: noncross-linked chitosan beads, coated with a chitosan/poly(acrylic acid- co-maleic acid) polyelectrolyte complex; genipin-cross-linked chitosan beads; and cross-linked chitosan beads, coated with a chitosan/poly(acrylic acid- co-maleic acid) polyelectrolyte complex. Trichoderma viride was immobilized either in the bulk or in the surface layer of the beads. The microbiological tests confirmed that T. viride immobilized in either mode maintained viability and the capacity to develop and to inhibit the growth of the pathogenic soil microorganisms, Alternaria and Fusarium.

A New Bifunctional Chitosanase Enzyme from Streptomyces sp. and Its Application in Production of Antioxidant Chitooligosaccharides

Chitosanases produced by microbes and plants are getting attention to explore vastly available marine waste. Chitooligosaccharides and glucosamine can be produced using chitosanase enzyme and have applications in food, pharma and other industries. A potential microbial chitosanase source was found after isolation and screening of chitosan degrading microbes from garden soil. An isolate, designated as C6 produced chitosanase enzyme upon induction by chitosan substrates. Production of 6 U/ml of chitosanase enzyme was achieved from this isolate on chitosan minimal salt broth medium at 32 °C after 3 days of growth. The enzyme was able to hydrolyse both chitosan and cellulosic substrates. Enzymatic production of D -glucosamine and chitooligosaccharides were studied with various chitosan substrates using crude enzyme. The yield of glucosamine was found to be 40% after 2 h of reaction at 40 °C, and chitosan oligomers were produced having two to six polymerizations at 60 °C reaction temperature. The hydrolysates showed 50% antioxidant activity as compared to ascorbic acid.

Corneal gene delivery: chitosan oligomer as a carrier of CpG rich, CpG free or S/MAR plasmid DNA

Corneal gene therapy can potentially treat acquired and inherited corneal disorders that otherwise lead to blindness. In a previous study on the development of effective vectors for corneal gene delivery, we showed that a particular formulation of chitosan-DNA nanoparticles, based on ultrapure chitosan oligomers injected into rat corneas, led to transgene expression that was 5.4-fold higher than that obtained using polyethylenimine-DNA nanoparticles. In the present study, we investigate the same formulation of chitosan-DNA nanoparticles as carriers of six different plasmids for corneal gene delivery. Size, zeta potential, the ability to condense plasmid DNA, and transfection efficiency in cell cultures and in rat corneas, were all investigated. Size, zeta potential, the ability to condense plasmid DNA, and transfection efficiency in cell cultures did not substantially vary for nanoparticles based on different plasmids. One day post-injection of nanoparticles into rat corneas, we found that a CpG-free plasmid DNA, pCpG-Luc, which has an EF1α promoter, led to transgene expression that was 7.1-fold higher than that for gWiz-Luc, a commercially available plasmid DNA with a cytomegalovirus (CMV) promoter used in our previous study; 116.8-fold higher than that for pEPI-CMV, a commercially available plasmid that has a scaffold/matrix attachment region (S/MAR) sequence and a CMV promoter; and 76.8-fold higher than that for pEPI-UbC, an experimental plasmid that has an S/MAR sequence and a ubiquitin C promoter. The present study reveals the potential of comparing various plasmids as an approach for enhancing transgene expression. The delivery system designed in the present study represents the next step in the development of effective vectors for corneal gene therapy.

Study on Synthesis Chitosan Oligomer Stabilized Silver Nanoparticles Using Green Chemistry and Their Burn Wound Healing Effects

ABSTRACTThe preparation of metal nanoparticles is a major research area in technical engineering due to their unusual properties, such as catalytic activity, novel electronic, optic and magnetic properties and biotechnology. Specially, silver has been used for years in the medical field for antimicrobial applications because it known for its antimicrobial properties and even has shown to prevent HIV binding to host cells. Common synthesis, chemical and physical methods using chemical reducing agent and organic solvent are not too suitable to have application to bioengineering because they should have associated environmental toxicity or biological hazards. Development of sustainable processes through green chemistry is attractive about the elimination or minimization of chemical waste. Here, we introduce the green method for preparation of silver nanoparticles using chitosan oligomer as both reducing and stabilizing agent in water. We expect that the use of environmentally benign solvent and chitosan oligomer to prepare silver nanoparticles offers numerous benefits and compatibility for pharmaceutical and biomedical applications.

Quantitative 3-D colocalization analysis as a tool to study the intracellular trafficking and dissociation of pDNA-chitosan polyplexes

Multichannel microscopy is frequently used to study intermolecular interactions and spatial relationships between biomolecules and organelles or vesicles in cells. Based on multichannel images, quantitative colocalization analysis can provide valuable information about cellular internalization, vesicular transport, and the intracellular kinetics and location of biomolecules. However, such analyses should be performed carefully, because quantitative colocalization parameters have different interpretations and can be highly affected by image quality. We use quantitative three-dimensional colocalization analysis of deconvolved and chromatic-registered confocal images to study the dissociation of double-labeled pDNA-chitosan polyplexes in HeLa cells and their colocalization with early endosomes. Two chitosans that form polyplexes with highly different transfection efficacies are compared. Pearson's correlation coefficient, Manders' colocalization coefficients, and the intensity correlation quotient are estimated to determine the intracellular localization of polyplexes, free pDNA, and free chitosans. Differences are observed in the amount of uptake, and in the intracellular pathways and rates of dissociation for the two chitosans. The results support previous findings that polyplexes formed by self-branched, glycosylated chitosan oligomers are more favorable for cellular uptake and intracellular trafficking to the nucleus compared with polyplexes formed by linear chitosans.

Cytotoxicity of Chitosan Oligomers Produced by Crude Enzyme Extract from the Fungus Metarhizium Anisopliae in Hepg2 and Hela Cells

Chitooligosaccharides exhibit biological activities, including antitumor, antimicrobial and antioxidant. In this study we used a mixture of chitooligosaccharides produced by enzymatic hydrolysis in two tumor cell lines and assessed the cell proliferation and cytotoxicity of these compounds. The proliferation of HeLa cells was inhibited around by 60%.

Gamma radiation synthesis of plasmonic nanoparticles for dark field cell imaging

Plasmonic nanoparticles including nanogold and nanosilver were prepared from a convenient gamma radiation route. Biocompatible copolymer chitosan oligomer was used as a template for nanoparticle growing. The obtained gold and silver nanoparticle colloids exhibited excellent water solubility and stability and these nanoparticles were well separated and uniform in size. They exhibited bright scattering light in a dark field owing to the surface plasmon resonance effect and could be easily detected even in a single-particle state. When cultured with cells, they would be internalised into cells and their intense scattering light made cells easily identifiable. These plasmonic nanoparticles obtained from the gamma radiation route could be used as promising contrast agents for multi-colour dark field cell imaging.

Chitinolytic and Chitosanolytic Activities from Crude Cellulase Extract Produced by A. niger Grown on Apple Pomace Through Koji Fermentation

Enzyme extracts of cellulase [filter paper cellulase (FPase) and carboxymethyl cellulase (CMCase)], chitinase, and chitosanase produced by Aspergillus niger NRRL-567 were evaluated. The interactive effects of initial moisture and different inducers for FP cellulase and CMCase production were optimized using response surface methodology. Higher enzyme activities [FPase 79.24+/- 4.22 IU/gram fermented substrate (gfs) and CMCase 124.04+/-7.78 IU/gfs] were achieved after 48 h fermentation in solid-state medium containing apple pomace supplemented with rice husk [1&percnt; (w/w)] under optimized conditions [pH 4.5, moisture 55% (v/w), and inducers veratryl alcohol (2 mM/kg), copper sulfate (1.5 mM/kg), and lactose 2% (w/w)] (p<0.05). Koji fermentation in trays was carried out and higher enzyme activities (FPase 96.67+/-4.18 IU/gfs and CMCase 146.50+/-11.92 IU/gfs) were achieved. The nonspecific chitinase and chitosanase activities of cellulase enzyme extract were analyzed using chitin and chitosan substrates with different physicochemical characteristics, such as degree of deacetylation, molecular weight, and viscosity. Higher chitinase and chitosanase activities of 70.28+/-3.34 IU/gfs and 60.18+/-3.82 to 64.20+/-4.12 IU/gfs, respectively, were achieved. Moreover, the enzyme was stable and retained 92-94% activity even after one month. Cellulase enzyme extract obtained from A. niger with chitinolytic and chitosanolytic activities could be potentially used for making low-molecular-weight chitin and chitosan oligomers, having promising applications in biomedicine, pharmaceuticals, food, and agricultural industries, and in biocontrol formulations.

Improved Enzymatic Depolymerization of Chitosan by Ionic Liquid Pretreatment and the Effect of Oligo-Chitosan on Intestinal Flora &lt;i&gt;In Vitro&lt;/i&gt;

It still remains challenging for effective hydrolysis of chitosan into chitosan oligomers. In this work, a pretreatment was conducted on chitosan by an ionic liquid 1-butyl-3-methylimidazolium chloride ([C4mim]Cl), aiming at improving enzymatic depolymerization of chitosan. X-ray diffraction analysis indicated that the inter- and intra-molecular hydrogen bonds within chitosan molecules were broken by [C4mim]Cl and the crystalline was destroyed. The oligo-chitosan hydrolyzed from IL-pretreated chitosan, coded as COS-IL, showed a DP of 3~5, in contrast to DP 5~8 with oligo-chitosan obtained from untreated chitosan(coded as COS-UN). COS-IL was more effective than COS-UN in inhibiting intestinal spoilage bacterials growth and it has positive effect on the growth of intestinal probiotic bacterials.

Chitosan oligomers as drug carriers for renal delivery of zidovudine

Abstract Chitosan oligomers (COS) are water soluble and can be a potential drug carrier for renal targeting delivery. Zidovudine (AZT), a FDA approved antiretroviral drug, has a very short half life and is eliminated very quickly in human plasma and kidney after administration. In this study, AZT-COS conjugates were prepared and evaluated in terms of renal targeting. The in vitro release of AZT from AZT-COS conjugates was confirmed in mice plasma and renal homogenate. The pharmacokinetics study indicated longer mean retention time of AZT-COS conjugates with the values of about 1.5 h than 0.59 h of AZT. The AZT-COS conjugates were found accumulated in kidney other than heart, liver, spleen, lung and brain after i.v. administration, in line with the evidence of the fluorescence imaging of FITC labeled COS in 12 h. In conclusion, AZT-COS conjugates have the potential to be developed into a renal-targeting drug delivery system.

Clean Preparation Process of Chitosan Oligomers in Gly Series Ionic Liquids Homogeneous System

Chitosan oligomers because of its water solubility has some special physiological functions, such as binding lipid, affecting the mitogenic response, restraining the growth of tumors, and was widely used in cosmetics and health. H2O2/Gly (Glycine) series ionic liquids system, a new solvable-catalytic system, was an efficient clean process for preparation of chitosan oligomers. The effects of the anions of Gly series ionic liquids on the solubility and degradation for chitosan were investigated, and the results showed that [Gly]Cl aqueous solution was of good solubility and assistant degradation for chitosan. In additional, the mechanism for oxidative degradation of chitosan in ionic liquids (ILs) was studied. The effect on the property of chitosan oligomers catalyzed by H2O2, in two different kinds of solvents (HAc and [Gly]Cl) were compared. It was found that the performance of moisture absorption and retention of chitosan oligomers using ionic liquid aqueous solution as solvent was better than that using HAc aqueous solution as solvent, and even superior to that of hyaluronic acid. Furthermore, [Gly]Cl could be easily separated from the product and reused with only slight loss. It could provide an efficient and environmental friendly method for the preparation of chitosan oligomers in H2O2/ILs system.