Applicative Study(Part I):The Excellent Conditions to Remove in Batch Direct Textile Dyes(Direct Red,Direct Blue and Direct Yellow)from Aqueous Solutions by Adsorption Processes on Low-Cost Chitosan Films under Different Conditions

In recent years the development of chitosan (CH) based materials as useful adsorbent polymeric matrices is an expanding field in the area of adsorption science. Even though CH has been successfully used for dye removal from aqueous solutions due to its low cost, no considerations have been made about, for example, the effect of changing the pH of chitosan hydrogelor about the dehydrating effect of Ethanol (EtOH) treatment of chitosan film on the dyes removal from water. Consequently in our laboratory we carried out a study focusing the attention, mainly, on the potential use of CH films under different conditions, such as reducing the intrinsic pH, increasing the hydrophobic character by means of ethanol treatment and neutralization of CH films to improve their absorption power. Textile anionic dyes named Direct Red 83:1, Direct Yellow 86 and Direct Blue 78 have been studied with the aim of reducing the contact time of CH film in waste water improving the bleaching efficiency. Neutralized acid CH film and longtime dehydrated one result to be the better films in dye removal from water. Also the reduction of the CH solution acidity during the film preparation determines the decreasing of the contact time improving the results. The effect of initial dye concentration has been examined and the amount of dye adsorption in function of time t, qt (mg/cm2), for each analyzed film has been evaluated comparing the long term effect with the decoloration rate. A linear form of pseudo-first-order Lagergren model has been used and described. The best condition for removing all examined dyes from various dye solutions appears to be the dehydration of a novel projected CH film obtained by means of the film immersion in EtOH for 4 days. Also CH films prepared by well-known literature procedure and neutralized with NaOH treatment appear having an excellent behavior, however the film treatment requires a large quantity of water and time.

Anastomotic stoma coated with chitosan film as a betamethasone dipropionate carrier for peripheral nerve regeneration

Scar hyperplasia at the suture site is an important reason for hindering the repair effect of peripheral nerve injury anastomosis. To address this issue, two repair methods are often used. Biological agents are used to block nerve sutures and the surrounding tissue to achieve phys- ical anti-adhesion effects. Another agent is glucocorticosteroid, which can prevent scar growth by inhibiting inflammation. However, the overall effect of promoting regeneration of the injured nerve is not satisfactory. In this regard, we envision that these two methods can be combined and lead to shared understanding for achieving improved nerve repair. In this study, the right tibial nerve was transected 1 cm above the knee to establish a rat tibial nerve injury model. The incision was directly sutured after nerve transection. The anastomotic stoma was coated with 0.5 × 0.5 cm^2 chitosan sheets with betamethasone dipropionate. At 12 weeks after injury, compared with the con- trol and poly （D, L-lactic acid） groups, chitosan-betamethasone dipropionate film slowly degraded with the shape of the membrane still intact. Further, scar hyperplasia and the degree of adhesion at anastomotic stoma were obviously reduced, while the regenerated nerve fiber structure was complete and arranged in a good order in model rats. Electrophysiological study showed enhanced compound muscle action potential. Our results confirm that chitosan-betamethasone dipropionate film can effectively prevent local scar hyperplasia after tibial nerve repair and promote nerve regeneration.

Development of Ficus carica Linn leaves extract incorporated chitosan films for active food packaging materials and investigation of their properties

The serious problems caused by extensive usage of petroleum-based plastic materials led to investigating the comprehensive studies and developing active food packaging materials.Even if the chitosan-based films are considered an attractive source,they exhibit some practical difficulties in developing active food packaging applications.Hence,Ficus carica Linn leaves extract(FLE),with the features of its cheapness,easy accessibility and superoxide anion radical scavenging activity,was incorporated into chitosan(CS)film at various concentrations(2%-6%w/w).To the best of our knowledge,this was the first time that FLE was utilized as a bioactive substance incorporated into chitosan films to develop eco-friendly,biodegradable,active food packaging material.The results obtained revealed that FLE incorporation into chitosan films significantly improved the swelling,water solubility and opacity of neat chitosan films.FTIR and morphological analysis indicated that the films produced exhibited smooth structure with homogenous dispersion of FLE.In mechanically,the addition of FLE resulted in a significant reduction in tensile strength while the elasticity of the films was improved.Additionally,the antioxidant and biodegradability properties of neat chitosan films were enhanced significantly.It was concluded that CS-FLE films appeared to be a capable and enhanced option for synthetic polymer-based food packaging materials.Based on the analyses performed,further studies are suggested on the packaging application for various foods and to evaluate the possible interaction of packaging film materials with the compounds of the food products,to avoid possible negative effects.

Integrated transcriptomic and proteomic study on the different molecular mechanisms of PC12 cell growth on chitosan and collagen/chitosan films

The purpose of this article is to integrate the transcriptomic analysis and the proteomic profiles and to reveal and compare the different molecular mechanisms of PC12 cell growth on the surface of chitosan films and collagen/chitosan films.First,the chitosan films and the collagen/chitosan films were prepared.Subsequently,the cell viability assay was performed;the cell viability of the PC12 cells cultured on the collagen/chitosan films for 24 h was significantly higher than that on the chitosan films.Then,with cDNA microarray,the numbers of differentially expressed genes of PC12 cells on the surface of chitosan and collagen/chitosan films were 13349 and 5165,respectively.Next,the biological pathway analysis indicated that the differentially expressed genes were involved in 40 pathways directly related to cell adhesion and growth.The integrated transcriptomic and our previous proteomic analysis revealed that three biological pathways-extracellular matrix-receptor interaction,focal adhesion and regulation of actin cytoskeleton-were regulated in the processes of protein adsorption,cell adhesion and growth.The adsorbed proteins on the material surfaces further influenced the expression of important downstream genes by regulating the expression of related receptor genes in these three pathways.In comparison,chitosan films had a strong inhibitory effect on PC12 cell adhesion and growth,resulting in the significantly lower cell viability on its surface;on the contrary,collagen/chitosan films were more conducive to promoting PC12 cell adhesion and growth,resulting in higher cell viability.

Electrochemical study and application on rutin at chitosan/graphene films modified glassy carbon electrode

Graphene（G） was dispersed into 0.5% chitosan（Chit） solution,then the composite films were coated on glassy carbon electrode（GCE）,the electrochemical behavior of rutin on a Chit/G modified GCE was investigated and the electrochemical parameters of rutin were calculated.Rutin effectively accumulated on the Chit/G/GCE and caused a pair of redox peaks at around 408 mV and 482 mV（vs.SCE） in 0.1M phosphate buffer solution（pH 4.0）.Under optimized conditions,the anodic peak current was linear to the rutin concentration in the range of 5×107-1.04×105M.The regression equation was：y 9.9219x-0.0025,r=0.9958.The proposed method was successfully used for the determination of rutin content in tablet samples with satisfactory results.

Preparation and Characterization of Chitosan/Carboxymethylated Konjac Glucomannan Blend Films

In order to improve the mechanical and water swelling properties of the chitosan (CS) film, a series of transparent films were prepared by blending 2%(weight) chitosan acetic acid solution with 1.5%(weight) carboxymethylated konjac glucomannan (CMKGM) aqueous solution according to predetermined ratio and drying at 30°C. The morphological structure, miscibility, thermal stability, mechanical properies, and swelling capacity of the blend films were studied by infrared (IR), X-ray diffraction (XRD), differential thermal analysis (DTA), scanning electron micrograph (SEM), and measurements of the mechanical properties and swelling properties. The results demonstrated that there was strong interaction and good miscibility between CS and CMKGM resulted from intermolecular hydrogen bonding and electrostatic force. The mechanical properties in dry state and wet state, thermostability, and water swelling properties of the blend films were obviously improved. The best values of the tensile strength in the dry and wet state achieved 89 MPa and 49 MPa, respectively, when the CMKGM content was 30%(weight). The CS/ CMKGM blend films provided promising biomedical applications.

A study of chitosan blend film as a carrier of corneal endothelial cells

In order to evaluate the cytocompatibility and biocompatibility of a new kind of chitosan blend film as a carrier of corneal endothelial cell, rabbit corneal endothelial cells cultured in vitro were breeded onto the film. After a cell monolayer formed, the scanning electron micrography was performed. After inplanted into anterior chamber, slit lamp observation, thickness metering, specular microscopy and HE staining were performed at random time after operation to evaluate the biocompatibility. Inflmmnation in anterior, thickness of cornea, cell density, hexagonality and cell size of the surgical cornea were taken as the indexes of biocompatibility. The cultured cells exhibited a confluent monolayer 10 days after incubation, which proved the satisfactory cytocompatibility of this film. Biocompatibility assay results suggested the implantation feasibility of the film as a carder of corneal endothelial cells.

Preparation and Charactcrization of a Novel PDLLA/Chondroitin Sulfate/Chitosan Asymmetry Film

A novel bioactive and bioresorbable asymmetry film was prepared. The PDLLA membrane was activated by 1, 6-hexanediamine to obtain a stable positive charge surface. Chondroitin sulfate and chitosan were then deposited on activated PDLLA membrane via layer-by-layer （LBL） electro-static assembly （ESA） technique. The deposition process was monitored by UV-Vis absorbance spectroscopy. The composite membrane was frozen lyophilized to form the asymmetry film and characterized by attenuated total reflectic （ATR）-FT-IR, XPS and SEM. The experimental results show that a stable 1, 6-hexanediamine layer on PDLLA substrate based on the aminolysis of the polyester and the layer thickness increase linearly first with the increase of the deposited layers, and then increases slowly due to the layer interpenetration. The test results of ATR-FT- IR and SEM show the asymmetry film is modified uniformly with a dense inner layer and a porous sponge outer tayer.

A Novel Biomolecular Immobilization Matrix Based on Nanoporous ZnO/Chitosan Composite Film for Amperometric Hydrogen Peroxide Biosensor

A novel ZnO/Chitosan composite matrix was developed to fabricate the H2O2 biosensor. This material combined the advantages of inorganic species, ZnO, and organic polymer, chitosan. Horseradish peroxidase immobilized in the material maintained its activity well as the usage of glutaraldehyde was avoided. The activity of enzyme was 7.9 times greater than the cross-linked enzyme. The parameters affecting the fabrication and experimental conditions of biosensors were optimized. With the aid of hydroquinone mediator, the biosensor had a fast response of less than 10 s. The linear range was 5.0×10-6 to 2.0× 10-3 mol/L with a sensitivity of 43.8 μA L/mmol. This matrix can also be used to immobilize other biomolecule.

Mechanical Properties of Collagen Biomimetic Films Formed in the Presence of Calcium,Silica and Chitosan

Using eucollagen solutions from ox hide, we cast collagen films to assess the influence of calcium and silica on the reconstitution of the fibrous structure of collagen. The tensile strength and the breaking elongation of the reconstituted collagen films were measured and analysed. Significant differences were observed between reconstituted collagen films with and without calcium and silica. The breaking elongation of the films obtained in the presence of silica was significantly greater, and the degradation was lower than other films of reconstituted collagen. Collagen and chitosan do not exist together as blends in nature, but the specific properties of each may be used to produce in biomimetic way man-made blends with biomedical applications, that confer unique structural, mechanical （detail） and in vivo properties.

Influence of Glutaraldehyde on the Properties and Release Kinetic of α-Tocopherol from Chitosan-based Film

A crosslinked chitosan film with α-tocopherol was produced by a solution casting method. The appearance, mechanical properties, morphology, barrier properties and release kinetics of the α-tocopherol were evaluated. The addition of glutaraldehyde and α-tocopherol decreased the lightness and greenness and increased the yellowness of the chitosan-based film. Moreover, it also affected the compatibility of the film due to a decrease in the opacity values. The elongation at break(EB) and tensile strength(TS) values of the film decreased when the glutaraldehyde and α-tocopherol were added. In contrast, the Young’s modulus(YM) values increased. SEM micrographs showed coarse spots and pores on the surface and cross-section of the film when compared with the chitosan film. Based on the results, it was indicated that the chitosan structure was disconnected by the α-tocopherol, and the glutaraldehyde as a crosslinking agent generated a link between the chitosan network, which could be the cause of the reduced flexibility and the increased surface roughness of the film. However, the glutaraldehyde and α-tocopherol did not result in a significant difference in water vapour permeability(WVP) values. The glutaraldehyde influenced the release kinetics of the α-tocopherol as seen by the decrease of the diffusion coefficient values that were calculated using the Fickian diffusion model.

Preparation of Fe_(3)O_(4) Film by in-situ Oxidative Hydrolysis on Chitosan

The Fe3O4 films were prepared by in-situ oxidative hydrolysis on chitosan. The structures and characteristics of the prepared Fe3O4 films were investigated by X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, atom force microscopy （AFM）, vibrating sample magnetometry （VSM） and thermogravimetric-differentia thermal analysis （TG-DTA）. The results show that, （1） the as-synthesized Fe3O4 films are pure Fe3O4 with cubic inverse spinel structure; （2） the network structured film can be obtained at lower temperature, and the compact particle film at higher temperature; （3） the prepared Fe3O4 films are super-paramagnetic, and the saturation magnetization is improved with increasing the reaction temperature, which is 49.03 emu/g at 80℃; （4） the temperature of phase transformation from Fe3O4 to a-Fe2O3 is about 495℃. Besides, the formation mechanism of Fe3O4 film was also proposed.

壳聚糖抗菌成膜喷剂在鼻咽癌患者PICC所致接触性皮炎治疗中的应用效果

目的探讨壳聚糖抗菌成膜喷剂在鼻咽癌患者经外周静脉置入中心静脉导管(PICC)置管部位接触性皮炎治疗中的应用效果。方法选取2020-05至2022-04联勤保障部队第909医院因置入PICC所致接触性皮炎的94例鼻咽癌患者为研究对象,其中2020-05至2021-04的46例患者为对照组,2021-05至2022-04的48例患者为观察组。对照组采用地塞米松注射液外涂联合3M透明敷料行PICC换药,观察组采用喷涂壳聚糖抗菌成膜喷剂联合3M透明敷料行PICC换药。对比观察两组患者临床疗效、并发症的发生率、愈合时间、换药次数、患者的自付费用及满意度情况。结果观察组治疗第1周、第2周总有效率(95.83%,100%)均显著高于对照组治疗总有效率(73.91%,89.13%)(P<0.05),观察组愈合时间[(10.43±0.52)d]、换药次数[(3.30±0.69)次]显著短于或少于对照组愈合时间[(18.15±0.33)d]、换药次数[(5.67±0.96)次](P<0.05),观察组患者满意度得分(8.71±0.82)显著高于对照组患者满意度得分(5.67±0.96)(P<0.05),两组患者在导管移位率、脱管率及患者自付费用三方面无明显区别,差异无统计学意义(P>0.05)。结论壳聚糖抗菌成膜喷剂治疗鼻咽癌同步放化疗患者PICC置管部位接触性皮炎效果明显,可减少换药次数,减轻护理工作量,降低局部感染率,提高患者满意度。

Production of chitosan-based composite film reinforced with lignin-rich lignocellulose nanofibers from rice husk

Lignocellulosic nanofibers(LCNFs),implying lignin-containing cellulose fibers,maintain the prop-erties of both lignin and cellulose,which are hydrophobic and hydrophilic,respectively.The pres-ence of hydrophobic lignin in LCNFs is expected to be an economical and attractive option that can improve the thermal and mechanical properties of polymers.Thus,this study was conducted to produce lignin-rich LCNFs from sugar-rich waste obtained from rice husks after acidic pretreat-ment.The LCNFs were produced from the lignin-rich solid fractions obtained after pretreatment and enzymatic hydrolysis,which were then incorporated as an additive into a chitosan-based film.The variations in lignin content in the range of approximately 50.6%-66.8%in differently obtained LCNFs gave significantly different optical strengths and mechanical properties.These controllable processes may allow for customized film formation.Additionally,the glucose-rich liquid fractions obtained after pretreatment and enzymatic hydrolysis were used as a substrate for ethanol fermentation to achieve total utilization of rice husk biomass waste.In conclusion,the lignin-rich biomass fraction holds promise as a suitable material for chitosan-LCNF film and has the potential to increase the economic feasibility of the biomaterial industry.

Adsorption of Toluene on Film Membranes of Chitosan/Nа-CMC

The sorption properties of films on bases of chitosan and sodium carboxyl methylcellulose (Na-CMC) with toluene have been checked. The sorption rate, sorption thermodynamics and isothermal properties of toluene molecules in chitosan/Na-CMC films are analyzed by adsorption-calorimetric method. Thus, it was found that toluene is adsorbed on the chitosan/Na-CMC film by the same patterns of sorption of aromatic compounds, due to the process of penetration of toluene molecules into the network of chitosan macromolecules and this is preceded by the absorption process by the surface of the chitosan/Na-CMC film.

Investigation of Chitosan-PVA Composite Films and Their Adsorption Properties

Viscous aqueous solutions of chitosan and polyvinyl alcohol (PVA) were blended to enhance miscibility and avoid polymer phase separation. The mixtures were drop-casted and air dried to yield composite film materials that were characterized by equilibrium water uptake, physical stability in aqueous solution, and thermal stability. Chitosan/PVA blends have greater thermal stability, unique morphology, and reduced solubility in acidic solution, thus extending the useful pH range for chitosan as a sorbent material. The uptake properties of the films was investigated using methylene blue (MB) and a p-nitrophenol (PNP) dyes, where it was found that each single component polymer has greater uptake toward MB than PNP. A direct relationship between film composition (chitosan:PVA) with solution pH and the uptake of MB was observed. The results are in agreement with electrostatic interactions and contributions due to the hydrophobic effect for such composite materials.

壳聚糖基多糖复合膜在食品包装中的研究进展

从力学性能、阻隔性能和抗菌活性等方面出发,综述了壳聚糖/纤维素、壳聚糖/淀粉、壳聚糖/果胶等壳聚糖基复合膜在食品包装中的研究进展,为壳聚糖基复合膜的研究提供了参考。

壳聚糖生物降解薄膜在食品保鲜包装中的应用进展

壳聚糖是天然高分子材料,其来源广,可再生,生物降解性和生物相容性良好,同时也具有优良的成膜性能、抗菌性能和抗氧化性能,在食品保鲜包装领域展现出巨大的应用前景。本文综述了壳聚糖生物降解薄膜的制备方法、改性方法和其在食品保鲜包装中的应用进展,并对壳聚糖生物降解薄膜的未来发展方向进行了展望。今后对壳聚糖食品包装材料的研究,应侧重于降低材料成本,提升材料的安全性;还应加强对新型壳聚糖复合材料的研究,以拓展其应用范围;此外,还应深入研究壳聚糖的保鲜机理和作用方式,从而提升其保鲜效果和适用性。

新型果蔬可食用复合保鲜膜的制备及其保鲜性能研究

为延长室温下果蔬贮藏期,以草莓为研究对象,壳聚糖、羟乙基纤维素、山茱萸油和CaCl_(2)为膜制剂材料,失重率、可溶性固形物含量和丙二醛含量为评价指标,采用单因素试验和四因素三水平的正交试验,考察复合涂膜对草莓保鲜效果的影响。试验结果表明,1.50%壳聚糖、0.75%羟乙基纤维素、1.20%山茱萸油和1.20%CaCl_(2)制备的复合保鲜膜对草莓的保鲜效果较好,能有效减少果实失重率和可溶性固形物含量损失,有效抑制丙二醛含量的生成和积累。

茶多酚对壳聚糖/肉桂醛复合膜性能及鱼肉保鲜效果比较

研究了不同茶多酚浓度对美拉德交联壳聚糖/海藻酸二醛-肉桂醛/壳聚糖-茶多酚(CMR/ADA-CA/CS-TP)三层复合膜性能及草鱼保鲜效果的影响。首先制备基于美拉德反应的壳聚糖交联层,随后层层浇铸海藻酸二醛-肉桂醛层和壳聚糖-茶多酚层,最后烘干成膜。当TP升高时,薄膜的颜色加深且透光率降低。薄膜(TP质量分数为0.04%)的拉伸强度升高至31.22 MPa;而薄膜的断裂伸长率则分布在19.59%~22.44%。然而,薄膜的水蒸气和氧气阻隔能力呈现下降的趋势。当TP质量分数为0.08%,薄膜的DPPH自由基清除能力提高至98.12%;培养24 h后金黄色葡萄球菌和大肠埃希氏菌的菌落总数较对照组减少了56.44%和56.29%。贮藏第8天时,活性膜包裹鱼肉的挥发性盐基氮、硫代硫酸巴比妥酸值和菌落总数较对照组分别降低了45.62%、50.70%和2.33 log CFU/g。综合考虑,TP质量分数为0.06%时,膜的整体性能较好,可延长鱼肉货架期,具有作为活性包装对易腐食品保鲜的潜力。