壳聚糖及其衍生物在生物医药中的研究进展

壳聚糖是一种用途很广的天然高分子化合物,具有无毒、生物相容性、吸附功能、生物可降解性及多种生物学活性等优异性能。本文综述了壳聚糖及其衍生物作为药物载体材料、组织工程材料、医用敷料和抗菌材料的应用,并且其在抗肿瘤方面也有一定的疗效。     

Recent Developments in Chitosan-Based Micro/Nanofibers for Sustainable Food Packaging,Smart Textiles,Cosmeceuticals, and Biomedical Applications

Chitosan has many useful intrinsic properties (e.g., non-toxicity, antibacterial properties, and biodegradability) and can be processed into high-surface-area nanofiber constructs for a broad range of sustainable research and commercial applications. These nanofibers can be further functionalized with bioactive agents. In the food industry, for example, edible films can be formed from chitosan-based composite fibers filled with nanoparticles, exhibiting excellent antioxidant and antimicrobial properties for a variety of products. Processing ‘pure’ chitosan into nanofibers can be challenging due to its cationic nature and high crystallinity; therefore, chitosan is often modified or blended with other materials to improve its processability and tailor its performance to specific needs. Chitosan can be blended with a variety of natural and synthetic polymers and processed into fibers while maintaining many of its intrinsic properties that are important for textile, cosmeceutical, and biomedical applications. The abundance of amine groups in the chemical structure of chitosan allows for facile modification (e.g., into soluble derivatives) and the binding of negatively charged domains. In particular, high-surface-area chitosan nanofibers are effective in binding negatively charged biomolecules. Recent developments of chitosan-based nanofibers with biological activities for various applications in biomedical, food packaging, and textiles are discussed herein.     

Application of Chitosan-Based Biomaterials for Blood Vessel Regeneration

Summary: Vascular diseases are the leading cause of morbidity and mortality in the western world. Autologous vessels remain the standard for coronary grafting and peripheral bypass surgery; however, their availability in patients can be limited. Therapeutic angiogenesis using growth factors, genes, or progenitor cells has been given considerable scientific attention over the last decade, but has not yet provided a definitive clinical benefit. Biomaterials could be developed to protect protein, DNA and cells against hostile conditions. Chitosan, a natural polymer of glucosamine and N-acetyl glucosamine, has been widely studied in tissue engineering due to its biocompatibility, biodegradability, and muco-adhesive and antimicrobial properties. Notably, the application of chitosan has been gaining attention in the vascular field due to its structural similarity to glycosaminoglycans, which are components of a tissue's extracellular matrix. In this review, chitosan-based materials, and their use in tissue engineered blood vessels, and as protein, gene and cell vectors for angiogenic therapy are discussed.     

聚乙二醇化壳聚糖的制备及其应用研究进展

聚乙二醇(PEG)是一种具有无毒、亲油亲水、高生物相容和无免疫原性等特点的化合物。将聚乙二醇结构引入壳聚糖(CTS)糖链中得到的聚乙二醇化壳聚糖,不但保持了CTS的天然性和优良生物降解等特性,还具有更好的水溶性和对有机化合物的结合能力。通过对CTS进行聚乙二醇化改性,可进一拓展其应用领域。本文结合近20年国内外PEG改性CTS的研究特点,围绕PEG改性CTS的制备及其在药物负载与控制释放、组织工程、抗菌材料、生物活性物传递和环境保护等领域的应用进行了总结,并展望其未来的发展趋势。     

Carbon dots enhanced gelatin/chitosan bio-nanocomposite packaging film for perishable foods

Carbon dots(CDs) with intriguing fluorescent property, good biocompatibility, high stability, easy interaction with substrates, are burgeoning carbon nanoparticles with large potential in various applications. Incorporating CDs into the polymer matrix is becoming a popular strategy to endow the complex with new functions. Herein, the green-synthesized CDs was integrated into the mixture of gelatin(derived from waste fish scale) and chitosan, and a multifunctional bio-nanocomposite(defined as Gel...     

Chitosan-Based Hydrogels for Infected Wound Treatment

Wound infections slow down the healing process and lead to complications such as septicemia, osteomyelitis, and even death. Although traditional methods relying on antibiotics are effective in controlling infection, they have led to the emergence of antibiotic-resistant bacteria. Hydrogels with antimicrobial function become a viable option for reducing bacterial colonization and infection while also accelerating healing processes. Chitosan is extensively developed as antibacterial wound dressings due to its unique biochemical properties and inherent antibacterial activity. In this review, the recent research progress of chitosan-based hydrogels for infected wound treatment, including the fabrication methods, antibacterial mechanisms, antibacterial performance, wound healing efficacy, etc., is summarized. A concise assessment of current limitations and future trends is presented.     

壳聚糖及其衍生物抗菌活性的研究进展

壳聚糖是自然界目前发现的唯一碱性多糖,具有自然来源丰富,生物相容性好,可被生物降解,安全无毒和抗菌性强等许多天然的优良特性,现其广谱抗菌性已得到广泛的认可,但较差的水溶性限制了它的进一步应用。因此,通过一定的改性方法制备壳聚糖衍生物以提高其水溶性,是目前壳聚糖研究方面的热点之一。本论文就近年来几种常见的壳聚糖亲水改性方法及其衍生物在抗菌方面的应用进展进行综述,以期对壳聚糖的深入研究提供参考。     

Preparation and Properties of Chitosan/Konjac Glucomannan Blend Fibers

Chitosan and konjac glucomannan (KGM) blend fibers were prepared by spinning their solution through a viscose‐type spinneret into a coagulating bath containing aqueous sodium hydroxide and ethanol. The structure and properties of the blend fibers were studied with the aids of infrared spectra (IR), scanning electron micrography (SEM) and X‐ray diffraction (XRD). The structure analysis indicated that there were strong interaction and good miscibility between the chitosan and KGM molecule which resulted from intermolecular hydrogen bonds. Mechanical properties and water‐retention properties were measured. Through controlling blend conditions, blend fibers can obtain better mechanical properties than the pure chitosan fiber. The water‐retention values (WRV) of blend fibers increase as the amount of KGM is raised. The fibers treated with alcoholic solution of acetic acid have good antibacterial activity to Staphylococcus aureus.     

Synthesis and characterization of amphiphilic antibacterial copolymers

Macromolecule antimicrobials have been explored in foundational research and practical application due to their potential merit for reducing the residual toxicity, increasing their efficiency, selectivity, and prolonging the lifetime of the antimicrobial material. In this work, the quaternized poly(styrene)‐b‐poly(DMAEMA) diblock polymers are synthesized by reversible addition‐fragmentation chain transfer polymerization (RAFT). The minimum inhibitory concentration (MIC) evaluation and optical density (OD) method demonstrated that the amphiphilic antibacterial biomaterials have exceptional antibacterial properties. The amphiphilic polycation has an admirable antibacterial property, and these quaternized diblocks are potent biocides and nonhemolytic. The relationship between the structure and activity is discussed with respect to molecular weight of the diblocks and bacteria structural dependence. Copyright © 2011 John Wiley & Sons, Ltd.     

羟烷基壳聚糖制备及应用研究进展

壳聚糖是由甲壳素通过脱乙酰作用得到的一种天然高分子多糖,具有良好的生物相容性、抗菌性、无毒和可生物降解等优点,但壳聚糖水溶性差限制了其在很多方面的应用。为克服壳聚糖在水溶性上的不足,利用壳聚糖结构中氨基和羟基上的活泼氢进行化学改性以引进羟烷基等亲水性基团成为重要手段。本文主要对壳聚糖羟烷基化改性的方法及羟烷基壳聚糖在医药、水处理和组织工程材料等领域的研究和应用现状进行介绍,并对羟烷基壳聚糖未来的发展趋势进行了展望。     

Mussel-Inspired Adhesive,Antibacterial, and Stretchable Composite Hydrogel for Wound Dressing

Hydrogels have attracted extensive attention in the field of biomedicine because of their similar structure to extracellular matrix (ECM) and good biocompatibility. However, the adhesiveness, mechanical properties, and antibacterial properties of conventional hydrogels are not satisfactory. In this study, multifunctional chitosan/polydopamine/polyacrylamide (CS/PDA/PAM) hydrogels are prepared through a nature-inspired strategy. The catechol group of polydopamine (PDA) component endows CS/PDA/PAM hydrogels with tissue adhesion and self-healing properties. The introduction of chitosan (CS) not only greatly improves antibacterial ability, but also enhances the mechanical properties of CS/PDA/PAM hydrogels. Skin wound healing experiments show that CS/PDA/PAM hydrogels could accelerate skin tissue regeneration and promote wound healing. Therefore, CS/PDA/PAM hydrogels have great potential in the application of new wound dressings.     

3D打印生物医用材料研究进展

3D打印(亦称增材制造)技术因其独特的材料成型优势,在组织工程、航空航天、汽车制造、以及电子工业等众多领域显示出巨大的应用潜力。然而,在实际生物医学应用中,3D打印生物器件和组织器官除了要求具有复杂的结构和优异的生物学性能外,其打印结构的表面性质也需满足某些特定的要求,如3D打印组织骨架和器官必须具有生物相容性、抗菌性及细胞粘附性等。因此,将3D打印与传统表面修饰技术相结合,在不改变材料三维结构的基础上调控其表面生物化学性质,从而赋予3D打印生物骨架器官多功能化,可实现更为广泛的应用。本文以3D打印生物骨架及器官的表面修饰为主要内容对就近年来3D打印生物医用材料的最新研究进展进行了综述。     

壳聚糖静电纺纳米纤维的制备和特点

对纯壳聚糖、壳聚糖和聚合物的混合物、壳聚糖和蛋白质的混合物、壳聚糖衍生物、壳聚糖和无机纳米颗粒的混合物等静电纺纳米纤维的制备和特点进行了综述,对部分壳聚糖纳米纤维的应用进行了简述。     

Thiol modified chitosan-silica nanohybrid for antibacterial,antioxidant and drug delivery application

Chitosan exhibits great versatility in various biomedical fields and mesoporous silica nanoparticles have emerged as an interesting material in biomedical areas owing to their outstanding physio-chemical properties. The combination of inorganic silica and organic polymer such as chitosan, make them suitable for a wide range of biomedical applications. Here, we have explored the benefits of chitosan and silica by synthesizing chitosan-silica nanohybrid. In the synthesis of chitosan-silica (CS–Si) nanohybrid, chitosan is modified by thioglycolic acid and mesoporous silica MCM-41(Mobil Composition of Matter number 41) is functionalized by 3-(trimethoxysilyl)-1-propane thiol (TMSP). The modified chitosan and thiol functionalized MCM-41(inorganic network) is then linked through disulfide bond by oxidation process or oxidative coupling, resulting in the formation of inorganic-organic hybrid material. The hybrid material was characterized by FTIR, Raman, XRD, TGA, Zeta potential, EDX, Proton NMR and SEM techniques. The antibacterial results indicated that gram-negative (E. coli) bacteria exhibit better inhibition zone than gram-positive (B. subtilis) bacteria. The DPPH scavenging capability of synthesized hybrid was found to be 68%. The drug (quercetin) encapsulation efficiency of hybrid material was calculated to be 92.38% and more drug releases in acidic medium (pH 5.0) than at pH 7.4, so we can conclude that hybrid material shows pH-dependent drug releasing behavior. The results show that synthesized nano-hybrid material possess good antibacterial and antioxidant activities and is also a good nanocarrier for drug delivery application.     

Design of antibacterial cellulose nanofibril film by the incorporation of guanidine-attached lignin nanoparticles

Cellulose - Cellulose nanofibril (CNF) films have attracted great attention in food packaging application due to their excellent mechanical strength and oxygen barrier properties. If antibacterial...     

Photocrosslinkable chitosan hydrogels and their biomedical applications

Chitosan is a bioactive macromolecule with a wide variety of applications due to its excellent biological properties such as biodegradability, biocompatibility, and antibacterial activity, and so forth. This highlight focuses on the preparation of photoactive chitosans, the formation of photocrosslinkable chitosan hydrogels, and the related photopolymerization mechanisms. Moreover, the great potential applications of photocrosslinkable chitosan hydrogels for human tissues are also discussed. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1862–1871     

Nanotechnology and its challenges in the food sector: a review

Antibacterial activity of nanoparticles has received significant attention worldwide because of their great physical and chemical stability, excellent magnetic properties, and large lattice constant values. These properties are predominate in the food science for enhancing the overall quality, shelf life, taste, flavor, process-ability, etc., of the food. Nanoparticles exhibit attractive antibacterial activity due to their increased specific surface area leading to enhanced surface reactivity. When nanoparticles are suspended in the biological culture, they encounter various biological interfaces, resulting from the presence of cellular moieties like DNA, proteins, lipids, polysaccharides, etc., which helps antibacterial properties in many ways. This paper reviews different methods used for the synthesis of nanoparticles but is specially focusing on the green synthesis methods owing to its non-toxic nature towards the environment. This review highlights their antibacterial application mainly in the food sector in the form of food-nanosensors, food-packaging, and food-additives. The possible mechanism of nanoparticles for their antibacterial behavior underlying the interaction of nano-particles with bacteria, (i) excessive ROS generation including hydrogen peroxide (H₂O₂), OH^? (hydroxyl radicals), and O^?₂ ² (peroxide); and (ii) precipitation of nano-particles on the bacterial exterior; which, disrupts the cellular activities, resulting in membranes disturbance. All these phenomena results in the inhibition of bacterial growth. Along with this, their current application and future perspectives in the food sector are also discussed. Nanoparticles help in destroying not only pathogens but also deadly fungi and viruses. Most importantly it is required to focus more on the crop processing and its containment to stop the post-harvesting loss. So, nanoparticles can act as a smart weapon towards the sustainable move.     

Milk Proteins—Their Biological Activities and Use in Cosmetics and Dermatology

Milk and colostrum have high biological potential, and due to their natural origin and non-toxicity, they have many uses in cosmetics and dermatology. Research is ongoing on their potential application in other fields of medicine, but there are still few results; most of the published ones are included in this review. These natural products are especially rich in proteins, such as casein, β-lactoglobulin, α-lactalbumin, lactoferrin, immunoglobulins, lactoperoxidase, lysozyme, and growth factors, and possess various antibacterial, antifungal, antiviral, anticancer, antioxidant, immunomodulatory properties, etc. This review describes the physico-chemical properties of milk and colostrum proteins and the natural functions they perform in the body and compares their composition between animal species (cows, goats, and sheep). The milk- and colostrum-based products can be used in dietary supplementation and for performing immunomodulatory functions; they can enhance the effects of certain drugs and can have a lethal effect on pathogenic microorganisms. Milk products are widely used in the treatment of dermatological diseases for promoting the healing of chronic wounds, hastening tissue regeneration, and the treatment of acne vulgaris or plaque psoriasis. They are also increasingly regarded as active ingredients that can improve the condition of the skin by reducing the number of acne lesions and blackheads, regulating sebum secretion, ameliorating inflammatory changes as well as bestowing a range of moisturizing, protective, toning, smoothing, anti-irritation, whitening, soothing, and antiaging effects.     

Fabrication of flexible AgNW/cellulose hybrid film with heat preservation and antibacterial properties for agriculture application

In the view of sustainable development and environmental protection, degradable agricultural films with on-demand thermal insulation properties have attracted growing research interest in the last few decades due to the deteriorating environment and extreme climate on the growth and existence of crops. Here, a general strategy has been developed to fabricate degradable silver nanowires modified cellulose (AgNW/cellulose) hybrid film with controllable thermal insulation and antibacterial properties by using plant cellulose and AgNWs as building blocks, PVA and PEG as film forming solvent, as well as their agriculture application. The results show that the AgNWs are evenly dispersed in the three-dimensional grid of cellulose, that they form a film that can withstand a certain tensile force and have good thermal stability. Due to the excellent electrical conductivity, the AgNW/cellulose hybrid films can provide excellent Joule heating, generating rapid thermal response and uniform electrical heating at a low supply voltage of 3 V. In the antibacterial tests against Escherichia coli and Staphylococcus aureus, the AgNW/cellulose hybrid films exhibited large diameters of inhibition zones, revealing the high antibacterial activity. Additionally, the AgNW/cellulose hybrid films showed highly stretchable behavior by delivering a breaking strain of 1.5% with a tensile stress of 0.45 MPa owing to the cross-linked structures of cellulose and AgNWs. Based on the above properties, this study not only provides a potential strategy for the fabrication of flexible and biodegradable agricultural films but also may provide new insights for agricultural thermal management.

     

Designing New Antibacterial Wound Dressings: Development of a Dual Layer Cotton Material Coated with Poly(Vinyl Alcohol)_Chitosan Nanofibers Incorporating Agrimonia eupatoria L. Extract

Wounds display particular vulnerability to microbial invasion and infections by pathogenic bacteria. Therefore, to reduce the risk of wound infections, researchers have expended considerable energy on developing advanced therapeutic dressings, such as electrospun membranes containing antimicrobial agents. Among the most used antimicrobial agents, medicinal plant extracts demonstrate considerable potential for clinical use, due primarily to their efficacy allied to relatively low incidence of adverse side-effects. In this context, the present work aimed to develop a unique dual-layer composite material with enhanced antibacterial activity derived from a coating layer of Poly(vinyl alcohol) (PVA) and Chitosan (CS) containing Agrimonia eupatoria L. (AG). This novel material has properties that facilitate it being electrospun above a conventional cotton gauze bandage pre-treated with 2,2,6,6-tetramethylpiperidinyl-1-oxy free radical (TEMPO). The produced dual-layer composite material demonstrated features attractive in production of wound dressings, specifically, wettability, porosity, and swelling capacity. Moreover, antibacterial assays showed that AG-incorporated into PVA_CS’s coating layer could effectively inhibit Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) growth. Equally important, the cytotoxic profile of the dual-layer material in normal human dermal fibroblast (NHDF) cells demonstrated biocompatibility. In summary, these data provide initial confidence that the TEMPO-oxidized cotton/PVA_CS dressing material containing AG extract demonstrates adequate mechanical attributes for use as a wound dressing and represents a promising approach to prevention of bacterial wound contamination.