Fabrication Of Bioactivity Polylactic Acid-Based Silver-containing Composite Fibers

Natural bone matrix is composed of fibrin(collagen)and minerals(apatite),which is a typical organic/inorganic composite material.The inorganic compounds in the composite provide the ability of bone conduction and bone bonding,while the polymer can be flexibly designed as a stent,the structure is stable,which can obtained a higher porosity and surface area.Bioactivity is one of the most important properties of electrospun fiber scaffolds for tissue growth.It is reported that mineralization can improve the bioactivity of materials and promote osteoblast activity and new bone formation.Bio-mineralization has been used to study the biological activity of materials.In this paper,the porous PLLA/Gel/n-Ag composite fibers with similar bone structure were prepared by electrospinning.And the electrochemical mineralization method to achieve the purpose of rapid mineralization of calcium phosphate on the surface of the fiber.The optimum conditions of electrospinning of PLLA-based composite fibers were mainly discussed.And compared with traditional in vitro immersion mineralization,and to explore its mechanism.At the same time,change the proportion of the material composition to adjust the hydrophobic properties of the composite fiber and nano-silver(n-Ag)content of calcium phosphate salt mineralization.It is expected to obtain an inorganic/organic composite biomaterial excellent in comprehensive performance.Specific research includes the following parts:(1)Preparation of pure PLLA fiber and optimization of experimental conditions.The results showed that the fiber diameter increases with the po lylactic acid concentration.The spinning is preferred when PLLA(10 million)concentration of 14% and 16%.Preparation of PLLA/n-Ag composite fibers and optimization of experimental conditions.The results showed that the n-Ag morphology is better when the n-Ag concentration is between 3% and 5%.The biological activity of PLLA,PLLA/n-Ag electrospun fibers was investigated by bio-mineralization.The effects of n-Ag concentration and deposition time on the morphology and mineralization of mineralized fibers were discussed.The results showed that the mineralized surface of the fiber is nano-scale and uniformly wrapped on the surface of the fiber.The amount of mineral deposition increases with time,the smaller the fiber diameter,the larger the amount of mineral deposition.(2)The bioactivity of PLLA,PLLA/n-Ag electrospun fibers was investigated by electrodeposition.The effects of electrolyte concentration and deposition time on the morphology and mineralization of mineralized fibers were discussed.The results showed that the morphology of the mineral is better when the electrolyte concentration is 16.7 mmol/L.The mineralized surface of the fiber is flaky,and the amount of mineral deposits increases with time.The larger the fiber diameter is,the larger the amount of mineralization is deposited.(3)Preparation of PLLA/Gel composite fiber.The bioactivity of the composites was investigated by simulated body fluid method.The effects of gelatin concentration(mass ratio of polylactic acid and gelatin were 90/10,80/20,70/30)on the biomineralization and mineralization of composite fibers were discussed.The results showed that the mineralization can be uniformly wrapped on the surface of the composite fiber,Gel can improve the hydrophilicity of the composite fiber.The more gelatin,the stronger the hydrophilicity of the composite fiber and the lower the mineralization amount.Preparation of PLLA/Gel/n-Ag composite fibers.The bioactivity of the composites was investigated by simulated body fluid method.The effects of n-Ag concentration(3%,5%,7%,9%)on the biomineralization and mineralization of composite fibers were discussed.The results showed that n-Ag has better conductivity during the electrospinning process,and the n-Ag surface of the fiber is more.In the process of bio-mineralization,which is conducive to calcium and phosphorus salt heterogeneous nucleation,thereby enhancing the mineralization of materials.The results showed that this paper has successfully proposed a preparation of PLLA/Gel/n-Ag ternary composite fiber,which can adjust the hydrophobicity of the material by changing the ratio of PLLA and Gel,and adjust the amount of n-Ag by changing the content of n-Ag and plays an important role in the preparation of inorganic/organic composite biomaterials with excellent performance.