| Currently, nosocomial infection is an outstanding problem in clinical that urged to besolved. At present, almost all of the raw materials that used for product medical apparatus,instruments, and artificial biological materials in clinical, such as polyurethane, siliconerubber, and natural rubber latex, does not have antibacterial activities. Thereforemicroorganisms are easy to attach and proliferate on the surface which becomes the chiefculprit of nosocomial infection. Researchers found that whether the long-term orshort-term biomaterials retained in the body often caused a variety of bacterial infections.According to the data from the U.S disease control and prevention center (CDC), thebuilt-in type medical equipment infection ranked fifth to all the death reason ofhospitalized patients in U. S, and about45%of hospital infections were associated with theuse of artificial biological materials. Develop materials of antibacterial properties forbiomedical materials application is of great significance.Ideal antibacterial biomaterials should have excellent antibacterial property, goodbiocompatibility and good formability, to ensure its application function. Silk Fibroin (SF)is a type of natural polymer material with good biocompatibility. At the same time, as theout protection shell material of silkworm through pupal stage, silk has the ability to resistagainst bad environment showing a certain degree of antibacterial activity, attract mostinterests of researchers in field of biological materials. However, pure SF has defects ofpoor formability, and poor antibacterial effect. Polyurethane (PU) is a kind of composed ofalternating hard and soft chain segment set polymer. It has excellent mechanical propertiesbecause of its unique micro phase separation structure, and was widely used in medicalapparatus and instruments such as artificial organs and medical catheter. However, as othersynthetic polymer materials, polyurethane also has problems of coagulation, calcificationand infection. Nano silver was widely used in the field of biomaterial because of itsproperties of broad-spectrum antimicrobial activity and avoiding occurrences of resistantbacteria. This project choose the silk fibroin and polyurethane to prepare silk/polyurethanecompound polymer, and add the antibacterial agent of Ag+to develop a new type of antibacterial composite materials contained with silver.Nanometer silk fibroin (SFP) was prepared by the process of salt dissolving andenzyme hydrolysis technology. SFP and PU at the different rate were resolved in the samesolvent of DMF to prepare the SFP/PU compounds and add silver nitrate to the system ofSFP/PU. Ag+can be removed by SF to silver nanoparticles and distribute in the compositecompound, and the silk/polyurethane composites material containing silver(SFP/PU/Ag)was obtained after removing the DMF solvent in water. A series of different specificationsof the composite material was prepared for testing the silver content and ratio of SFP/PUinfluence on material properties. The composite film materials were prepared throughsolvent phase transformation method for investigating the structure and properties of thesecomposite materials. The structure of SFP/PU/Ag were characterized by UV, IR, SEM,TG-DSC, and RGR tensile test; Weightlessness measurement were carried out to study thestability of the material in water and simulated body fluid; The antibacterial properties ofSFP/PU/Ag film were investigated by bacteriostatic ring qualitative test and bacteriostaticrate quantitative test method; The cytotoxicity of the composite material were determinedby MTT method. The blood compatibility of SFP/PU/Ag film composite materials wasinvestigated by hemolytic test, dynamic coagulation test, and platelet adhesion test.The results showed that SFP/PU at weight ratio of30/70, silver at content SFP/PUsystem total quality of1%, the morphology of silver nanoparticles were the most excellent;Silk fibroin embedded in SFP/PU/Ag composite material in shape of tiny linear-particles ormicrospheres, and the size of silver particles were about50~200nm and had a certaindegree of gatherings and distribution in SFP/PU/Ag film internally and externally. Themechanical properties can be adjusted by controlling the ratio of SFP/PU, and SFP/PU at30/70shows the most excellent tensile strength. SFP/PU/Ag film materials in water andsimulated body fluid (SBF) solution occur a low loss rate, better stability, suggests thatmaterials have a stable combine way; From the antibacterial test, the obvious bacteriostaticring larger than7mm were found, showing that all composite materials contained withsilver (SFP/PU/Ag) show strong antibacterial effect on escherichia coli, staphylococcusaureus, and pseudomonas aeruginosa. Cytotoxicity test results show that SFP/PU/Ag filmmaterial most cytotoxic score are at0or1showing slightly effect on cell growth but doesnot lead to cytotoxicity, conform to the requirements of the cellular compatibility ofbiological materials; Blood compatibility test results show that SFP/PU/Ag compositemembrane of the hemolysis rate was less than5%, and have a certain anticoagulant effect,platelet consumption rate were lower than40%, conform to the requirements of biomedical materials.The results preliminarily proved that the composite materials could be a goodcandidate of medical device surface coating materials or medical catheter materialsapplication. |
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