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Because antibacterial biological dressing has good biocompatibility, antibacterial anti-inflammatory properties, such dressings have been closely watched at home and abroad and deep-level research, which is reflected in the treatment of burns a significant advantage, in recent years, is widely used in clinical treatment. The antibacterial properties of biological dressings largely determines its raw materials, preparation process and microstructure. The first task of chitosan (CS) / alcohol (PVA) sponge preparation, that the CS and PVA compound, obtained by acetalization reaction of CS / PVA sponge. Test results showed that the product compact and uniform pores, the size of each through hole. The water absorption, moisture resistance, air permeability, tensile strength was 464%, 42.5%, 36.7%, 56.3 MPa, CS / PVA sponge porosity of 83%, mostly in diameter 200μm between 450μm. Acetalized PVA has a dense crosslinked structure of the foam obtained to ensure high tensile strength; porous dense structure makes the material has good water absorption, and permeability; CS and PVA are rich in hydrophilic hydroxy and amino groups, to ensure that materials of high water absorption and moisture. MTT assay shows that the material L929 mouse fibroblasts for no obvious toxicity, indicating that the composition of the material has good biological activity, and the optimal preparation of the material also ensures histocompatibility. Secondly, in the pre-test the prepared CS / PVA sponge structure and properties of defects, try adding PVA-1799 to PVA-AH26 in order to improve the structure and properties of materials. Mechanical device using wildcard, SEM, mercury instrument, such as testing methods, improved study of the physical properties of materials, including water absorption, moisture rate, permeability, material morphology, pore size parameter, pore size distribution, etc., while the two kinds of products listed on the comparison of the performance, so as to explore prepare CS / PVA sponge optimal formulation and process. The results show that, CS / PVA sponge porosity and pore size distribution, water absorption and air permeability rate of PVA-1799 content with increasing, and this is because of the low degree of PVA-1799 better foaming properties and can produce more foam structure, making CS / PVA foam sponge PVA-1799 content with increasing distribution is more uniform, dense; PVA-AH26 higher degree of polymerization, high molecular weight, and it is acetalized a high degree of crosslinking, high strength, can enhance the mechanical strength of the material, so that CS / PVA sponge tensile strength with increasing content of PVA-AH26 is enhanced; these two types of PVA have a large amount of hydroxyl groups, with chitosan sugar, amino and hydroxy, ensuring CS / PVA sponge high moisture rate reached 94%. By listing the product performance and Two, it was found PVA ratio of AH26: 1799 = 8:2 was obtained when the CS / PVA sponge the best overall performance, its porosity, density, pore size distribution, tensile strength, water absorption , moisture ratio, permeability rates were 86%, 0.346g / cm 3 , 420 6 60μm (maximum distribution of 500μm), 56Mpa, 601%, 98%, 37 %. Comprehensive physical properties of the product marketed products with these two quite meet the medical sponge skin dressings physical performance requirements. Thirdly, the nano-silver antimicrobial material (containing silver SiO 2 ) added to the pre-prepared CS / PVA sponge to explore this new material as an antibacterial biological dressings possibilities. By ethanol / water / NaOH solution, construct a nanoscale adsorbed phase reactor, adsorption of silver nanoparticles prepared nano SiO 2 powder; would contain silver SiO 2 powder is added to the CS / PVA reaction solution obtained by the acetalization reaction of Ag / SiO 2 nanoparticles CS / PVA sponge. TEM images show that the particle size distribution of nano-silver 5 1 0nm, uniformly dispersed in SiO 2 colloid; XRD results show that Ag / SiO 2 4 particles of silver strong peaks corresponding to (111), (200), (220), (311) crystal plane, and the sample is very sharp diffraction peaks, indicating that the silver particles have a good face-centered cubic structure, and good crystal, is calculated according to Scherrer formula nano silver particles have an average diameter of 8.87 nm, and a TEM photograph consistent with the results observed; UV-Vis test results show that most of the silver nanoparticles to Ag 2 O form, only a small part to elemental silver Ag 0 exist; DSC test result appears in nano-Ag particles transition temperature 340 ℃; nano silver in vitro release profiles showed the presence of burst release, gentle to accelerate the release of three stages, the cumulative release of 89%. Through research material on L929 mouse fibroblasts toxicity, cells found in this material did not produce significant toxicity, and have the effect of promoting the cell growth. By studying the product sterilization experiments and found that the product of the Staphylococcus aureus, Escherichia coli, Candida albicans, Pseudomonas aeruginosa and Salmonella typhi five kinds of experimental strains have good bactericidal effect. Finally, the nano-silver antibacterial materials (nano-silver / PEG solution) added to the pre-prepared CS / PVA sponge to explore the biological material as an antimicrobial dressing possibilities. By reduction in polyglycol of nano silver particles, and the acetalization reaction of PVA, the nano silver / PEG solution was added to CS / PVA blend solution was prepared containing nano silver / PEG - CS / PVA sponge. TEM images show a particle size distribution of nano-silver 10 2 0nm, good dispersibility; XRD results show that the sample containing silver (111), (200), (220) crystal plane three , and the crystal is very good, according to Scherrer formula diameter of nano-silver particles in the TEM photograph consistent with the results observed; UV-Vis test results show that the sample occurs at 275nm and 355nm characteristic absorption peak of silver, nano-silver large partly in Ag 2 O form, only a small part to elemental silver Ag 0 exist; Nano Silver Nano vitro release curve shows the presence of silver release burst release, gentle two phase, the cumulative release of 95%. MTT assay that the material on L929 mouse fibroblast cells did not produce significant toxicity. By studying the product sterilization experiments and found that the product of the five kinds of experimental strains have good bactericidal effect. Therefore, in this study the above two products may be new biological antimicrobial dressings.
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