Constructing Composite Biofilms And Multilayer Microcapsules Of Nanosilver/Biopolymer

Biopolymers are well known examples for renewable source and environmental friendly polymeric materials. Biopolymers have been used widely in biomedical fields for their excellent biocompatibility, biodegradability, renewability. And they may positively support cell adhesion and function. However, some biopolymers show poor mechanical and environment resistance properties or are limited in antibacterial properties. Nanotechnology is a most promising technology for its wide range of applications in medicine. For example, silver at nanoscale exhibits remarkably unusual physical, chemical and biological properties. Due to their strong antibacterial activity, nanosilver coatings can be used to prepare various textiles as well as coatings of certain implants. Recently, many workers focus on the combination of biopolymer and nanosilver to construct various composite. In this work, we have prepared biopolymer/nanaosilver composite, and then characterized its performance utilizing the corresponding instruments.First, we present a new method to construct biopolymer/nanoparticle composite films with conductivity and antibacterial activity by electrodeposition. This method can be employed to build biopolymer/nanoparticle composite hydrogels or coatings on various electrodes or conductive substrates. It is found that the deposited hydrogels and their dried films are smooth and homogeneous due to the elimination of H2 bubbles by addition of H2O2 in electrodeposition process. Importantly, the composite films are strong enough to completely and readily be peeled from the electrodes after reacting with EDC, which can prepare a type of biopolymer/nanoparticle film for further applications. Furthermore, the electrodeposition technique is able to offer controllable and convenient method to construct composite films with diverse shapes. The composite films display improved conductivity and in vitro antibacterial activity against Escherichia coli and Staphylococcus aureus, which may provide attractive applications in biomedical fields such as artificial muscles, skin biomaterials and neuroprosthetic implants.Second, we employ nanosilver and microbial transglutaminase as modifiers to improve the performance of the gelatin. We hope to obtain a kind of biomaterial with good biocompatibility, nontoxicity, as well as improved mechanical strength, stability and antibacterial activity. We use rheological test to study the process of gel formation of silver/gelatin composite. Compared with gelatin, silver/gelatin composite shows better antibacterial activity. With its improved stability, mechanical strength and antibacterial activity, this enzymatically modified silver/gelatin composite could be a promising biomaterial in further applications of skin tissue engineering.Third, we assemble a microfluidic channel for controllable preparation of sodium carboxymethylcellulose/chitosan multilayer capsules, which are assembled by electrostatic interaction. We use microscope to study the morphology of multilayer capsules. The multilayer capsules can encapsulate different materials(e.g., fluorescent materials and nanoparticles) at the same time. This is an effective method for weakening the interaction of the capsuled materials due to being encapsulated in multilayer framework.In this work, nanosilver is enlisted as a modifier to improve the performance of biopolymer materials, such as chitosan, gelatin, and sodium carboxymethylcellulose. We use electrodeposition technology to construct chitosan/gelatin/nanosilver composite films, and utilize gas-liquid microfluidic method to prepare sodium carboxymethylcellulose/chitosan multilayer microcapsules. The biopolymer/nanosilver composite could be a promising biomedical material in further applications. It can also provide an effective method for the construction of other biopolymers/nanosilver composite materials.