The comparison of the effect of enzyme, peroxide, plasma and chitosan processes on wool fabrics and evaluation for antimicrobial activity

Pretreated (enzymatic and enzymatic+hydrogen peroxide) knitted wool fabrics were treated with atmospheric argon and air plasma to improve their adsorption capacity. After plasma treatments chitosan solution was applied to have antimicrobial effect on wool fabrics. The treated fabrics were evaluated in terms of washing stability as well as antimicrobial activity. The surface morphology was characterised by SEM images and FTIR analysis. From the results it was observed that atmospheric plasma treatment had an etching effect and increased the functionality of a wool surface. Atmospheric plasma treatment also enhanced the adhesion of chitosan to the surface and improved the antimicrobial activity of the wool sample. Argon was found to be more effective than air, since argon radicals played an important role in killing and removing bacteria. No significant difference in washing durability was observed in terms of plasma treatments. The samples of combined pretreatment processes had good washing durability even after 10 washing cycle. From the SEM images it was observed that combination of plasma and the other pre-treatment processes gave less damage than only one process.     

Study of antimicrobial activity of aloevera, chitosan, and curcumin on cotton, wool, and rabbit hair

Aloevera, chitosan, and curcumin were applied in alone and in combination with each others on cotton, wool and rabbit hair by exhaustion method for the assessment of their antimicrobial activity. The antimicrobial activity of these natural ingredients was better in peroxide treated cotton, formic acid treated wool/rabbit hair fibrous substrates than their corresponding intact ones. Aloevera shown better antimicrobial activity than chitosan and curcumin when applied alone and its antimicrobial activity was enhanced by addition of both chitosan and curcumin. The application of aloevera+chitosan+curcumin combination on peroxide treated cotton and formic acid treated wool/rabbit hair fibrous substrate was fast up to twenty five washing cycles.     

壳聚糖处理对采后建阳桔柚果实品质和贮藏特性的影响

探讨不同浓度壳聚糖处理对采后建阳桔柚果实在(10±1)℃下贮藏的生理特性、营养品质和贮藏特性的影响。结果表明：与对照果实相比,壳聚糖处理能降低建阳桔柚果实的呼吸强度,延缓果皮细胞膜透性的升高,抑制果实表面色调角h°值下降,果肉能保持较高的可溶性固形物、可滴定酸度、总糖、维生素C和类胡萝卜素含量,减少建阳桔柚果实失重和腐烂,保持较高商品率。其中以稀释500倍壳聚糖处理的保鲜效果最佳,果实商品率一直保持在95%以上,感病指数控制在0.1以下,而且果肉基本无汁胞枯水现象,贮藏后期果实的失重率可控制在5%以内。因此认为,稀释500倍壳聚糖处理是保持采后建阳桔柚品质、延长其保鲜期的有效方式。     

Long-Term Feeding of Chitosan Ameliorates Glucose and Lipid Metabolism in a High-Fructose-Diet-Impaired Rat Model of Glucose Tolerance

This study was designed to investigate the effects of long-term feeding of chitosan on plasma glucose and lipids in rats fed a high-fructose (HF) diet (63.1%). Male Sprague-Dawley rats aged seven weeks were used as experimental animals. Rats were divided into three groups: (1) normal group (normal); (2) HF group; (3) chitosan + HF group (HF + C). The rats were fed the experimental diets and drinking water ad libitum for 21 weeks. The results showed that chitosan (average molecular weight was about 3.8 × 10⁵ Dalton and degree of deacetylation was about 89.8%) significantly decreased body weight, paraepididymal fat mass, and retroperitoneal fat mass weight, but elevated the lipolysis rate in retroperitoneal fats of HF diet-fed rats. Supplementation of chitosan causes a decrease in plasma insulin, tumor necrosis factor (TNF)-α, Interleukin (IL)-6, and leptin, and an increase in plasma adiponectin. The HF diet increased hepatic lipids. However, intake of chitosan reduced the accumulation of hepatic lipids, including total cholesterol (TC) and triglyceride (TG) contents. In addition, chitosan elevated the excretion of fecal lipids in HF diet-fed rats. Furthermore, chitosan significantly decreased plasma TC, low-density lipoprotein cholesterol (LDL-C), very-low-density lipoprotein cholesterol (VLDL-C), the TC/high-density lipoprotein cholesterol (HDL-C) ratio, and increased the HDL-C/(LDL-C + VLDL-C) ratio, but elevated the plasma TG and free fatty acids concentrations in HF diet-fed rats. Plasma angiopoietin-like 4 (ANGPTL4) protein expression was not affected by the HF diet, but it was significantly increased in chitosan-supplemented, HF-diet-fed rats. The high-fructose diet induced an increase in plasma glucose and impaired glucose tolerance, but chitosan supplementation decreased plasma glucose and improved impairment of glucose tolerance and insulin tolerance. Taken together, these results indicate that supplementation with chitosan can improve the impairment of glucose and lipid metabolism in a HF-diet-fed rat model.     

Surface modification of PET film and fabric by oligo-chitosan treatment

Poly(ethylene terephthalate) (PET) films, comprising surfaces hydrolyzed with caustic soda solution to incorporate the functional groups of carboxylic acids, were treated with a solution containing chitosan oligomer, a cross-linking agent, and a catalyst in order to modify various surface characteristics, including hydrophilicity and anti-staticity. Chitosan oligomers were prepared by depolymerizing chitosan with sodium nitrite. The chitosan molecules were fixed to the PET film surface by the reaction between the carboxylic groups in the PET film and the amino groups of the chitosan molecules. FT-IR(ATR) spectra, surface free energies, anti-staticity and other properties were measured and interpreted in relation to the structural change that was induced in the PET films by these treatments. In addition, we investigated the effect of chitosan oligomer treatment on the handle of polyester fabrics by using Kawabata evaluation system. The hydrophilic and anti-static properties of the PET film were highly improved by alkaline hydrolysis and low-molecular-weight chitosan treatment. The handle of PET fabric was gradually hardened by chitosan treatment with increasing the concentration of chitosan.     

不同浓度壳聚糖处理对采后西番莲果实耐贮性和贮藏品质的影响

为研究不同浓度壳聚糖处理对采后西番莲果实耐贮性和贮藏品质的影响,选取采后‘福建百香果1号’西番莲果实,用稀释50倍、100倍、150倍、200倍、250倍的卡多赞（壳聚糖）溶液浸泡5 min,以用蒸馏水浸泡5 min为对照,果实浸泡后取出晾干,之后用0.015 mm厚的聚乙烯薄膜袋密封包装（每袋装果10个）,置于28℃和相对湿度80%条件下贮藏,贮藏期间每隔3 d取样,用于测定西番莲果实的耐贮性和贮藏品质指标。结果表明：与对照西番莲果实相比,壳聚糖处理能有效降低采后西番莲果实的呼吸强度,延缓果皮细胞膜透性的上升,降低果实失重率,保持较高的果实商品率;此外,壳聚糖处理能保持较高的外果皮L ^*、a ^*、b ^*值及果皮花色素苷、类黄酮和总酚含量,维持较高的果肉可溶性固形物、可滴定酸、可溶性总糖、蔗糖、维生素C和类胡萝卜素含量。因此,壳聚糖处理能增强采后西番莲果实的耐贮性和维持较高的贮藏品质;其中,以稀释200倍的卡多赞溶液处理的保鲜效果最佳,可作为提高西番莲果实采后耐贮性、延长其保鲜期的适宜处理条件。     

Preparation and Characterization of Ferrofluid Stabilized with Biocompatible Chitosan and Dextran Sulfate Hybrid Biopolymer as a Potential Magnetic Resonance Imaging (MRI) T2 Contrast Agent

Chitosan is the deacetylated form of chitin and used in numerous applications. Because it is a good dispersant for metal and/or oxide nanoparticle synthesis, chitosan and its derivatives have been utilized as coating agents for magnetic nanoparticles synthesis, including superparamagnetic iron oxide nanoparticles (SPIONs). Herein, we demonstrate the water-soluble SPIONs encapsulated with a hybrid polymer composed of polyelectrolyte complexes (PECs) from chitosan, the positively charged polymer, and dextran sulfate, the negatively charged polymer. The as-prepared hybrid ferrofluid, in which iron chloride salts (Fe³⁺ and Fe²⁺) were directly coprecipitated inside the hybrid polymeric matrices, was physic-chemically characterized. Its features include the z-average diameter of 114.3 nm, polydispersity index of 0.174, zeta potential of −41.5 mV and iron concentration of 8.44 mg Fe/mL. Moreover, based on the polymer chain persistence lengths, the anionic surface of the nanoparticles as well as the high R2/R1 ratio of 13.5, we depict the morphology of SPIONs as a cluster because chitosan chains are chemisorbed onto the anionic magnetite surfaces by tangling of the dextran sulfate. Finally, the cellular uptake and biocompatibility assays indicate that the hybrid polymer encapsulating the SPIONs exhibited great potential as a magnetic resonance imaging T2 contrast agent for cell tracking.     

Chitin and Chitosan: Prospective Biomedical Applications in Drug Delivery,Cancer Treatment,and Wound Healing

Chitin and its derivative chitosan are highly abundant polymers in nature, appearing in both the shells and exoskeletons of various marine and non-marine species. Since they possess favorable properties, such as biocompatibility, biodegradability, non-toxicity, and non-immunogenicity, they have gained recent attention due to their enormous potential biomedical applications. The polycationic surface of chitosan enables it to form hydrogenic and ionic bonds with drug molecules, which is one of its most useful properties. Because chitosan is biocompatible, it can therefore be used in drug delivery systems. The development of chitosan-based nanoparticles has also contributed to the significance of chitin as a drug delivery system that can deliver drugs topically. Furthermore, chitin can be used in cancer treatment as a vehicle for delivering cancer drugs to a specific site and has an antiproliferative effect by reducing the viability of cells. Finally, chitosan can be used as a wound dressing in order to promote the faster regeneration of skin epithelial cells and collagen production by fibroblasts. As discussed in this review, chitin and chitosan have diverse applications in the medical field. Recognizing the biomedical applications of these two polymers is essential for future research in tissue engineering and nanobiotechnology.     

Controlling Properties and Cytotoxicity of Chitosan Nanocapsules by Chemical Grafting

The tunability of the properties of chitosan-based carriers opens new ways for the application of drugs with low water-stability or high adverse effects. In this work, the combination of a nanoemulsion with a chitosan hydrogel coating and the following poly (ethylene glycol) (PEG) grafting is proven to be a promising strategy to obtain a flexible and versatile nanocarrier with an improved stability. Thanks to chitosan amino groups, a new easy and reproducible method to obtain nanocapsule grafting with PEG has been developed in this work, allowing a very good control and tunability of the properties of nanocapsule surface. Two different PEG densities of coverage are studied and the nanocapsule systems obtained are characterized at all steps of the optimization in terms of diameter, Z potential and surface charge (amino group analysis). Results obtained are compatible with a conformation of PEG molecules laying adsorbed on nanoparticle surface after covalent linking through their amino terminal moiety. An improvement in nanocapsule stability in physiological medium is observed with the highest PEG coverage density obtained. Cytotoxicity tests also demonstrate that grafting with PEG is an effective strategy to modulate the cytotoxicity of developed nanocapsules. Such results indicate the suitability of chitosan as protective coating for future studies oriented toward drug delivery.     

Effect of chitosan addition on the surface properties of kenaf (Hibiscus cannabinus) paper

The present paper studies the effect of chitosan, cationic starch and polyvinyl alcohol (PVA) as sizing agents to enhance surface properties of kenaf paper. The polymers were incorporated into the sheets by spray application. The results clearly showed that the addition of chitosan to a sheet formed from beaten fibers had excellent improvement in surface properties, compared to the effect of other additives. Sizing quality of cationic starch fairly matched with the sizing quality of chitosan, however, it was able to reduce the water absorption potential of paper more than chitosan at a same concentration. In most other properties, particularly the most important property for printing papers, surface smoothness, chitosan-sized papers are superior to the paper sized with cationic starch or PVA.     

A new application method of chitosan for improved antimicrobial activity on wool fabrics pretreated by different ways

Antimicrobial treatments have become more important for the textile materials especially used in sportswear, activewear, and casual wear since they can easily be contaminated by perspiration leading to bacterial growth and body odor. In this work, antimicrobial activity of chitosan in a silica matrix on pretreated wool fabrics was studied. The pretreatment processes were applied by two different ways (enzymatic and enzymatic+hydrogen peroxide). Afterwards chitosan solutions were applied to the untreated samples and to the samples that were pretreated by two different ways to give antimicrobial effects. The antimicrobial activity of wool fabrics treated in various methods was assessed before and after repeated washings (up to 10 cycles) by the application of standard test method AATCC 147-1998. The morphology of the treated fabrics was investigated by SEM and their characterizations were made by the FT-IR spectral analysis. Results revealed that pretreatment ways and chitosan application methods were quite important for adsorption and diffusion of chitosan on wool fabrics and washing stability. From the SEM images, it was clearly observed that pretreatment processes caused some degradation on the surface of the fiber; but combined processes were found to be less degradative and more effective.     

Synthesis,Characterization, and Antibacterial Activity of Cross-Linked Chitosan-Glutaraldehyde

This present study deals with synthesis, characterization and antibacterial activity of cross-linked chitosan-glutaraldehyde. Results from this study indicated that cross-linked chitosan-glutaraldehyde markedly inhibited the growth of antibiotic-resistant Burkholderia cepacia complex regardless of bacterial species and incubation time while bacterial growth was unaffected by solid chitosan. Furthermore, high temperature treated cross-linked chitosan-glutaraldehyde showed strong antibacterial activity against the selected strain 0901 although the inhibitory effects varied with different temperatures. In addition, physical-chemical and structural characterization revealed that the cross-linking of chitosan with glutaraldehyde resulted in a rougher surface morphology, a characteristic Fourier transform infrared (FTIR) band at 1559 cm⁻¹, a specific X-ray diffraction peak centered at 2θ = 15°, a lower contents of carbon, hydrogen and nitrogen, and a higher stability of glucose units compared to chitosan based on scanning electron microscopic observation, FTIR spectra, X-ray diffraction pattern, as well as elemental and thermo gravimetric analysis. Overall, this study indicated that cross-linked chitosan-glutaraldehyde is promising to be developed as a new antibacterial drug.     

Fabrication of superhydrophobic cellulose/chitosan composite aerogel for oil/water separation

Superhydrophobic cellulose and chitosan composite aerogel (SCECS) is fabricated through a novel and simple approach for the first time. During the preparation of cellulose and chitosan composite aerogel (CECS), chitosan is selfassemble into number micron-diameter particles on the surface of aerogel, which is similar to the micromorphology of a lotus leaf. Based on the rough surface, CECS is modified by sodium stearate through electrostatic interaction and ion exchange. Water contact angles of 156° are obtained for superhydrophobic aerogel. SCECS can remove various oils from water and with absorption capacities of 10 g/g for oil. Furthermore, the special structure of a non-porous of surface and porous layer of internal is benefit to separate surfactant-stabilized water-in-oil emulsions under gravity.     

Enhancing Stability and Mucoadhesive Properties of Chitosan Nanoparticles by Surface Modification with Sodium Alginate and Polyethylene Glycol for Potential Oral Mucosa Vaccine Delivery

Background: The present study aimed to fabricate surface-modified chitosan nanoparticles with two mucoadhesive polymers (sodium alginate and polyethylene glycol) to optimize their protein encapsulation efficiency, improve their mucoadhesion properties, and increase their stability in biological fluids. Method: Ionotropic gelation was employed to formulate chitosan nanoparticles and surface modification was performed at five different concentrations (0.05, 0.1, 0.2, 0.3, 0.4% w/v) of sodium alginate (ALG) and polyethylene glycol (PEG), with ovalbumin (OVA) used as a model protein antigen. The functional characteristics were examined by dynamic light scattering (DLS), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM)/scanning transmission electron microscopy (STEM). Stability was examined in the presence of simulated gastric and intestinal fluids, while mucoadhesive properties were evaluated by in vitro mucin binding and ex vivo adhesion on pig oral mucosa tissue. The impact of the formulation and dissolution process on the OVA structure was investigated by sodium dodecyl-polyacrylamide gel electrophoresis (SDS-PAGE) and circular dichroism (CD). Results: The nanoparticles showed a uniform spherical morphology with a maximum protein encapsulation efficiency of 81%, size after OVA loading of between 200 and 400 nm and zeta potential from 10 to 29 mV. An in vitro drug release study suggested successful nanoparticle surface modification by ALG and PEG, showing gastric fluid stability (4 h) and a 96 h sustained OVA release in intestinal fluid, with the nanoparticles maintaining their conformational stability (SDS-PAGE and CD analyses) after release in the intestinal fluid. An in vitro mucin binding study indicated a significant increase in mucin binding from 41 to 63% in ALG-modified nanoparticles and a 27–49% increase in PEG-modified nanoparticles. The ex vivo mucoadhesion showed that the powdered particles adhered to the pig oral mucosa. Conclusion: The ALG and PEG surface modification of chitosan nanoparticles improved the particle stability in both simulated gastric and intestinal fluids and improved the mucoadhesive properties, therefore constituting a potential nanocarrier platform for mucosal protein vaccine delivery.     

Potassium silicate and chitosan application for gray mold management in strawberry during storage

The objective of this study was to investigate the effect of silicon and chitosan as alternative controls for postharvest rot of strawberries (gray mold) caused by Botrytis cinerea. Chitosan and potassium silicate applications were performed at the preharvest stage using the following treatments: chitosan once a week; potassium silicate once a week; potassium silicate once a week + chitosan once a week; and without application. An additional variable was introduced at postharvest, with one-half of the total fruit harvested from each plot dipped in chitosan and the other half not dipped in chitosan. Potassium silicate alone was not effective for rot control. Fruits from plants that received the chitosan application showed 64% less area under the rot progress curve (AURPC) than fruits from plants that were not treated with chitosan. Harvested fruits that were chitosan dipped showed 48% less AURPC than fruits that were not treated at postharvest. Chitosan application in the field and at postharvest is a promising strategy for the management of postharvest strawberry rot.     

壳聚糖处理对采后西番莲果实贮藏期间果皮活性氧代谢的影响

西番莲属于热带果实,采后西番莲果实容易腐烂变质,导致其保鲜期很短,限制了其商业价值。为探讨壳聚糖（卡多赞）处理对采后西番莲果实贮藏期间果皮活性氧代谢的影响,采后‘福建百香果1号’西番莲果实经卡多赞稀释200倍溶液处理5 min,以蒸馏水处理为对照,在(28±1)℃、相对湿度80%条件下贮藏。每隔3 d,测定西番莲果实果皮超氧阴离子自由基（O₂^-·）产生速率、过氧化氢（H₂O₂）含量、丙二醛（MDA）含量、活性氧清除相关酶活性、内源抗氧化物质含量及DPPH自由基清除能力和还原力的变化。结果表明：壳聚糖处理能显著提高西番莲果实果皮超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）等活性氧清除酶活性,保持较高的还原型抗坏血酸（AsA）和还原型谷胱甘肽（GSH）等内源抗氧化物质含量,维持较高的DPPH自由基清除能力和还原力,从而抑制采后西番莲果实果皮O₂^-·和H₂O₂等活性氧的产生,减轻果皮膜脂过氧化,稳定果皮细胞膜结构,最终保持采后西番莲果实的贮藏品质、提高其果实耐贮性。因此认为,卡多赞稀释200倍溶液处理能有效提高采后西番莲果实的活性氧清除能力,降低活性氧积累,从而延缓采后西番莲果实衰老进程,延长其果实保鲜期。     

Dye Adsorption from Aqueous Solution by Cellulose/Chitosan Composite: Equilibrium,Kinetics, and Thermodynamics

A novel eco-friendly porous adsorbent of cellulose (CE)/chitosan (CS) aerogel was prepared through sol-gel process and freeze-drying to remove Congo Red (CR). A series of aerogels were prepared by adjusting the mass ratios of CE and CS. Composite aerogels were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). SEM images showed that it was possible to change the structure of the aerogel by adjusting the amount of chitosan. The effects of dosage of chitosan, initial pH, temperature, adsorbent dosage, contact time, and initial dye concentration on adsorption capacities for CR were studied in detail. Batch adsorption studies showed that aerogel exhibited maximum removal efficiency to CR at a composite ratio of 1:3 and dosage of 2.5 g/l. CE/CS aerogel had excellent adsorption capacities for CR at a pH range of 3-11, which indicated stability of the aerogel in both acidic and alkaline conditions. CR adsorption on the composite aerogel fitted pseudo-second-order kinetics and Langmuir isotherm. The Langmuir isotherm model revealed that the maximum theoretical adsorption capacity of this material for CR was 381.7 mg/g at pH 7.0 at 303 K for 24 h. The adsorption mechanism included electrostatic and chemical interactions. The results indicated that the adsorption capacity of CE/CS aerogels was higher than the other chitosan composites adsorbents.     

Expression and Biochemical Characterization of a Novel Marine Chitosanase from Streptomyces niveus Suitable for Preparation of Chitobiose

It is known that bioactivities of chitooligosaccharide (COS) are closely related to the degree of polymerization (DP); therefore, it is essential to prepare COS with controllable DP, such as chitobiose showing high antioxidant and antihyperlipidemia activities. In this study, BLAST, sequence alignment and phylogenetic analysis of characterized glycoside hydrolase (GH) 46 endo-chitosanases revealed that a chitosanase Sn1-CSN from Streptomyces niveus was different from others. Sn1-CSN was overexpressed in E. coli, purified and characterized in detail. It showed the highest activity at pH 6.0 and exhibited superior stability between pH 4.0 and pH 11.0. Sn1-CSN displayed the highest activity at 50 °C and was fairly stable at ≤45 °C. Its apparent kinetic parameters against chitosan (DDA: degree of deacetylation, >94%) were determined, with K_m and k_cat values of 1.8 mg/mL and 88.3 s⁻¹, respectively. Cu²⁺ enhanced the activity of Sn1-CSN by 54.2%, whereas Fe³⁺ inhibited activity by 15.1%. Hydrolysis products of chitosan (DDA > 94%) by Sn1-CSN were mainly composed of chitobiose (87.3%), whereas partially acetylated chitosan with DDA 69% was mainly converted into partially acetylated COS with DP 2-13. This endo-chitosanase has great potential to be used for the preparation of chitobiose and partially acetylated COS with different DPs.     

Hemostatic,antibacterial and degradable performance of the water-soluble chitosan-coated oxidized regenerated cellulose gauze

In this research, the oxidized regenerated cellulose (ORC) gauze was prepared by oxidation of regenerated cellulose using NO₂/CCl₄, subsequently treated with the dissolved chitosan (CTS) in aqueous acetic acid (CTS/ORC) and finally neutralized with NaOH/C₂H₅OH (CTS/ORC-Na). The hemostatic, antibacterial and degradable properties of treated ORC-based gauze were evaluated. The results of the hemostatic test on rabbit liver and ear-artery injuries showed that the attachment of high molecular weight chitosan to the surface of ORC gauze significantly improved the hemostatic effect of ORC without compromising the antibacterial and degradability of ORC. It is found that the water-soluble CTS/ORC-Na gauze was more suitable as the hemostatic material applied in rabbit liver injury in comparison with in ear-artery injury and it further improved the hemostatic efficacy and enhanced the degradable rate. It is promised that the CTS/ORC gauze and the water-soluble CTS/ORC-Na gauze would be applicable in medical fields such as surgical absorbable hemostats for control bleeding.     

Preparation of Chito-Oligomers by Hydrolysis of Chitosan in the Presence of Zeolite as Adsorbent

An increasing interest has recently been shown to use chitin/chitosan oligomers (chito-oligomers) in medicine and food fields because they are not only water-soluble, nontoxic, and biocompatible materials, but they also exhibit numerous biological properties, including antibacterial, antifungal, and antitumor activities, as well as immuno-enhancing effects on animals. Conventional depolymerization methods of chitosan to chito-oligomers are either chemical by acid-hydrolysis under harsh conditions or by enzymatic degradation. In this work, hydrolysis of chitosan to chito-oligomers has been achieved by applying adsorption-separation technique using diluted HCl in the presence of different types of zeolite as adsorbents. The chito-oligomers were retrieved from adsorbents and characterized by differential scanning calorimetry (DSC), liquid chromatography/mass spectroscopy (LC/MS), and ninhydrin test.