Chitosan Biopolymer Schiff Base: Preparation,Characterization, Optical,and Antibacterial Activity

Natural biopolymer used for hydrogels has attracted increasing attention in the multifaceted areas of biomedical science and engineering. The authors prepared chitosan biopolymer Schiff base by solvent exchange method using a simple aliphatic crosslinker, crotanaldehyde. The identity of Schiff base was confirmed by UV-vis and Fourier-transform infrared spectroscopy. The chitosan Schiff base was evaluated by XRD, TGA, DSC, and SEM. The microbiological screening results demonstrated the antibacterial activity of Schiff base against Escherichia coli and Staphylococcus aureus bacteria. These results suggest that the newly prepared Schiff base may open a new perspective in biomedical applications.     

壳聚糖抗菌活性研究进展

壳聚糖具有无毒、良好的生物相容性、生物可降解性、广谱抗菌性等优良性能,作为新型抗菌剂越来越受学者的青睐。本文主要综述了21世纪以来影响壳聚糖抗菌性能的因素、壳聚糖的抗菌机理以及壳聚糖衍生物抗菌性能等方面的内容。     

Selected Applications of Chitosan Composites

Chitosan is one of the emerging materials for various applications. The most intensive studies have focused on its use as a biomaterial and for biomedical, cosmetic, and packaging systems. The research on biodegradable food packaging systems over conventional non-biodegradable packaging systems has gained much importance in the last decade. The deacetylation of chitin, a polysaccharide mainly obtained from crustaceans and shrimp shells, yields chitosan. The deacetylation process of chitin leads to the generation of primary amino groups. The functional activity of chitosan is generally owed to this amino group, which imparts inherent antioxidant and antimicrobial activity to the chitosan. Further, since chitosan is a naturally derived polymer, it is biodegradable and safe for human consumption. Food-focused researchers are exploiting the properties of chitosan to develop biodegradable food packaging systems. However, the properties of packaging systems using chitosan can be improved by adding different additives or blending chitosan with other polymers. In this review, we report on the different properties of chitosan that make it suitable for food packaging applications, various methods to develop chitosan-based packaging films, and finally, the applications of chitosan in developing multifunctional food packaging materials. Here we present a short overview of the chitosan-based nanocomposites, beginning with principal properties, selected preparation techniques, and finally, selected current research.     

Chitosan: Application in tissue engineering and skin grafting

Tissue Engineering and skin grafting, an essential part of regenerative medicine is one of the fastest growing biomedical fields which could offer an important therapeutic strategy for management of hard to heal wounds. 2D and 3D polymeric scaffolds are prerequisites in this field to promote cell adhesion, proliferation and tissue regeneration. Convergence of technology and research has successfully unveiled unknown properties of Chitosan as a bioactive polymer. Natural abundance, cost effectiveness, biodegradability, biocompatibility and wound healing capabilities of chitosan and its derivatives has drawn the attention of many researchers for its use as an alternative for fabrication of a scaffold in tissue engineering and skin graft. However lower mechanical strength and solubility has limited its application in the biomedical field. It has been found that the derivatization and combination with other polymers can successfully overcome these limitations. This review focuses on the applicability of chitosan and its derivatives in combination with other polymers in tissue engineering and skin grafting along with the novel scaffold fabrication techniques. Studies so far have demonstrated the potential of chitosan and its derivative as a scaffold in the field of regenerative medicine. However, even if the promising results obtained from in-vitro and preclinical studies prove the efficacy of chitosan scaffolds it still has a long way to go to be used in clinical set ups.     

壳聚糖及其衍生物的制备和保湿吸湿性能评价

简要介绍了壳聚糖及其衍生物的制备方法和物化性质。以甘油、山梨醇和透明质酸为参照物，在一定相对湿度下考察了壳聚糖、羧甲基壳聚糖、N—羧丁基壳聚糖等几种保湿剂的保湿吸湿性能。结果显示，羧甲基壳聚糖和N—羧丁基壳聚糖的保湿吸湿性能最优，完全可以替代透明质酸，作为多种化妆品的保湿剂。     

Chitosan adsorbents for dye removal: a review

One of the most important decontamination techniques is considered to be adsorption. It is fast, simple, low cost with many opportunities to modify the initial materials after appropriate synthesis routes etc. Numerous adsorbent materials have been prepared in the last few years having as the ultimate scope to remove some pollutants especially from contaminated waters (effluents originating from industry). But the composition of each type of effluent varies. Dyes are some major components of industrial wastewaters. Chitosan (poly‐β‐(1 → 4)‐2‐amino‐2‐deoxy‐d ‐glucose) is a nitrogenous (amino‐based) polysaccharide which is produced in large quantities by N‐deacetylation of (its source compound) chitin. The major advantage of chitosan is the existence of modifiable positions in its chemical structure. Modification of the chitosan molecule by (i) grafting (inserting functional groups) or (ii) crosslinking reactions (uniting the macromolecular chains with each other) leads to the formation of chitosan derivatives with superior properties (enhancement of adsorption capacity and resistance in extreme medium conditions, respectively). This review summarizes the important contribution of chitosan derivatives to the dye removal process by adsorption. © 2017 Society of Chemical Industry     

Chitosan for wastewater treatment

Chitosan (an amino‐polysaccharide obtained from deacetylation of chitin, the major constituent of crustaceous shells and insect cuticles) presents a cationic character in acidic media allowing its dissolution, its shaping and possible ion‐exchange interactions with anionic compounds (a property applied in adsorption and coagulation–flocculation processes). In neutral media, non‐protonated amino groups allow complexation of metal cations or organic chemicals. These different properties explain the interest taken by the scientific community in using this biopolymer. In solution it contributes to complex metals and their recovery by complexation‐assisted ultrafiltration. It can also be used to coagulate–flocculate organic compounds (as anionic dyes). In the solid state, it can be used for metal ion adsorption, as well as adsorption of organic compounds (dyes, pesticides, drugs, endocrine disruptors, etc.). The adsorption and coagulation–flocculation processes will be compared and examples considered. Moreover, it is noteworthy that the thermal degradation of this type of material is also more environmentally friendly than that of conventional synthetic resins (production of hazardous by‐products, etc.), a supplementary advantage of these biopolymer‐based sorbents. Combined with its ability to be chemically or physically modified improving the potential and phase separation of chitosan‐based materials, all these properties mean it is an excellent candidate for wastewater treatment. © 2017 Society of Chemical Industry     

羟丙基纤维素／壳聚糖抗菌剂的制备及性能研究

以天然纤维素醚衍生物羟丙基纤维素和壳聚糖为基本原料,制备了羟丙基纤维素／壳聚糖（CSPC）抗菌剂。利用傅立叶变换红外光谱（FT-IR）、热重一差热分析（TG-DSC）、静置法、最小抑菌浓度（MIC）对CSPC抗菌剂进行表征,结果表明该抗菌剂一方面具有优良的抑菌特性,且抑制真菌生长的能力强于细菌,另一方面具有对温度的敏感特性,CSPC抗菌剂耐温性可达250℃,且酸碱稳定性良好。     

Fabrication of Chitosan/Silk Fibroin Composite Nanofibers for Wound-dressing Applications

Chitosan, a naturally occurring polysaccharide with abundant resources, has been extensively exploited for various biomedical applications, typically as wound dressings owing to its unique biocompatibility, good biodegradability and excellent antibacterial properties. In this work, composite nanofibrous membranes of chitosan (CS) and silk fibroin (SF) were successfully fabricated by electrospinning. The morphology of electrospun blend nanofibers was observed by scanning electron microscopy (SEM) and the fiber diameters decreased with the increasing percentage of chitosan. Further, the mechanical test illustrated that the addition of silk fibroin enhanced the mechanical properties of CS/SF nanofibers. The antibacterial activities against Escherichia coli (Gram negative) and Staphylococcus aureus (Gram positive) were evaluated by the turbidity measurement method; and results suggest that the antibacterial effect of composite nanofibers varied on the type of bacteria. Furthermore, the biocompatibility of murine fibroblast on as-prepared nanofibrous membranes was investigated by hematoxylin and eosin (H&E) staining and MTT assays in vitro, and the membranes were found to promote the cell attachment and proliferation. These results suggest that as-prepared chitosan/silk fibroin (CS/SF) composite nanofibrous membranes could be a promising candidate for wound healing applications.     

Synthesis and antimicrobial activity of Schiff base of chitosan and acylated chitosan

Chitosan, a biocompatible, biodegradable, nontoxic polymer, is prepared from chitin, which is the second most naturally occurring biopolymer after cellulose. Schiff base of chitosan, sorbyl chitosan, and p‐aminobenzoyl chitosan were synthesized working under high‐intensity ultrasound and their antimicrobial properties were analyzed against Escherichia coli, Staphylococcus aureus, and Aspergillus niger. The structures of the derivatives were characterized by FTIR spectroscopy and elemental analysis. The results of antimicrobial activities indicated that the antimicrobial activities of the derivatives increased with increasing the concentration. The antibacterial activity of schiff base of chitosan against E. coli was stronger, while acylated chitosan had better inhiting effect on S. aureus than others. It was also found that the antifungal activities of the derivatives were stronger than that of chitosan, and schiff base of chitosan was obviously superior to acylated chitosan. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Antibacterial effects of chitosan and its water‐soluble derivatives on E. coli,plasmids DNA,and mRNA

The antibacterial activities of chitosan and its water‐soluble derivatives on E. coli were studied according to four influencing factors in vitro. The antibacterial study showed that chitosan, O‐hydroxyethyl chitosan (O‐HECS), and O‐carboxymethyl chitosan (O‐CMCS) could inhibit the growth of the microbial. To study the antibacterial mechanism, plasmid DNA pBR322 and pUC18 were selected to be the probes to find out the binding abilities of chitosans. Results showed that raw chitosan had a high binding ability with the plasmids and the influencing degrees were stable. The effects of chitosan derivatives on plasmids might be affected by space effect and static effect. With appropriate concentrations and molecular weights, the derivatives might have strong abilities to combine with DNA. The degree of influence of chitosan and its derivatives on plasmids had nothing to do with time. The experiment focusing on the relationship between chitosans and mRNA showed that O‐CMCS would hinder the synthesis of mRNA, and this may give some proof to its antibacterial mechanism. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3521–3528, 2007     

壳聚糖在纤维制品中的应用

综述了壳聚糖在造纸和壳聚糖纤维方面的应用。在造纸方面,壳聚糖可用做纸张增强剂、施胶剂、助留助滤剂、表面改性剂和造纸废液的絮凝剂。壳聚糖纤维具有抗菌性和透气性等优良性能。     

壳聚糖及其衍生物与碘的络合物的抑菌性质研究

利用壳聚糖(CTS)、水杨醛改性壳聚糖(S-CTS)和还原水杨醛改性壳聚糖(RS-CTS)与碘以不同质量比制备络合物,通过碘量法测络合物的摩尔比,UV光谱和IR光谱对络合物进行了表征。考察了CTS和RS-CTS与碘络合物的抑菌性质。结果表明,壳聚糖及其衍生物与碘络合物摩尔比(壳聚糖及其衍生物结构单元与碘之比)分别为:n(CTS)∶n(I2)=1∶0.38,n(S-CTS)∶n(I2)=1∶0.85,n(RS-CTS)∶n(I2)=1∶0.73。CTS和RS-CTS与碘的络合物对金黄色葡萄球菌抑菌敏感度为高度敏感。     

The Effect of Pimelic Acid Interaction on the Mechanical and Thermal Properties of Chitosan and Collagen

An attempt was made on to evaluate the feasibility on interaction of pimelic acid with natural polymers, namely chitosan and collagen, and further assess the functional, mechanical, thermal and biocompatible properties. Pimelic acid cross-linked 3D-scaffold biopolymer of chitosan and collagen displayed appreciable mechanical strength, thermal stability, and biocompatibility. The chemistry of interaction suggested noncovalent interactions play a major role in deciding the property of the said materials and its suitability for biomedical applications.     

壳聚糖及其衍生物对金属离子吸附研究进展

壳聚糖是一种天然高分子,分子中含有大量的氨基和羟基,对金属离子有很好的吸附能力.本文综述了壳聚糖及其衍生物对金属离子的吸附研究情况,并对其发展前景作了展望.     

壳聚糖C6位选择性氧化的研究进展

壳聚糖及其衍生物由于具有良好的生物活性、生物相容性、抗菌性和无毒等性能被广泛应用于众多领域。壳聚糖C6位选择性氧化为羧基的氧化剂主要有N2O4、NO2、CrO3、TEMPO/NaClO/NaBr体系和NaClO2/KBr/4,4’-二(2,2,5,5-四甲基咪唑-3-氧化-1-氧基自由基)苯基醚体系等。国内研究壳聚糖C6位选择性氧化的程度还远远不及国外,有待于在前人工作的基础上不断改进和开发氧化壳聚糖的方法。     

壳聚糖的抗菌机理及其化学改性研究

壳聚糖具有优良的生物特性和广谱、高效的抗菌活性,是开发研制天然抗菌剂的理想对象。概述了壳聚糖对于细菌和真菌的抗菌机理研究以及在增强溶解性和提高抑菌活性方面的化学改性研究。     

壳聚糖及其衍生物在天然织物整理中的应用研究进展

壳聚糖具有良好的抗菌性、吸湿性、反应活性和成纤性,作为新型织物整理剂在纺织产业具有广泛的应用前景。本文综述了近年来壳聚糖及其衍生物在天然织物抗菌、染色、阻燃、防静电、抗紫外和防毡缩等整理中的应用,并就其赋予织物各项性能的机理及影响因素进行讨论。采用对壳聚糖进行改性、与金属化合物的复合使用和对织物表面进行超声、等离子等预处理的方法有利于改善其对织物的整理效果,并对织物的各项物理性能起积极作用。未来壳聚糖基整理剂可在加强某个单一性能的基础上,选择性地引入多个功能性基团,合成符合应用需求的环保型多功能整理剂。     

壳聚糖衍生物的红外光谱分析

合成了以下多种壳聚糖衍生物并测定了它们的红外光谱。这些衍生物是羧酸化壳聚糖 ,苯甲酰化壳聚糖 ,氰乙基壳聚糖 ,羟丙基壳聚糖 ,羟乙基壳聚糖 ,N -羧甲基化壳聚糖 ,壳聚糖的苯甲醛西佛碱 ,N -乙基壳聚糖 ,N -丁二酰化壳聚糖 ,N -顺丁烯二酰化壳聚糖 ,N -邻苯二甲酰化壳聚糖和N -乙酰化壳聚糖。观察到随壳聚糖脱乙酰度的增加 ,酰胺Ⅰ谱带移向低频 ,而酰胺Ⅲ谱带和醇羟基谱带移向高频 ,结果可用氢键的变化加以解释。脂肪族酰化壳聚糖的取代基长度对C =O位置影响很小 ,它们的C =O都能与邻近的N -H和O -H基生成相似的氢键。氰乙基壳聚糖的取代度影响了C -O谱带的位置 ,低取代的 1 0 70cm- 1 和 1 0 30cm- 1 双峰在高取代时被 1 0 61cm- 1 单峰所代替。通过IR测定 ,对丁二酰化壳聚糖和顺丁烯二酰化壳聚糖观察到含自由羧基端的线形取代 ,对邻苯二甲酰化壳聚糖 ,在反应程度较高时还出现环状取代。羧酰化壳聚糖、氰乙基壳聚糖和邻苯二甲酰化壳聚糖的取代度可分别用吸光度比A1 740 /A1 52 7,A2 2 4 9/A1 52 7和A1 71 2 /A1 391 测定     

Chemical Modifications of Chitosan and Its Applications

Chitosan is considered as a promising material in the pharmaceutical and biomedical fields based on its unique biological properties. This review presents chemical modifications of chitosan via using photosensitizers, dendrimers, sugars, cyclodextrins and crown ethers as modifiers and places an emphasis on the applications of chitosan derivatives as carriers in drug delivery systems, as supporting materials for tissue engineering, as dye removing agents and as metal ion adsorbents. Recently, the progress on chemical modifications of chitosan is quite rapid and we are confident that a more extensive range of applications of chitosan derivatives could be expected in the near future.