Preparation Of Composite Silk Films Containing Silk Microfibers For Artificial Meniscus

Silk is a kind of natural protein-based fiber that has excellent strength and toughness.Silk fibroin has good biocompatibility and it’s degradation product is harmless to thehuman body. Silk fibroin composite materials have been widely used in drug delivery andtissue engineering fields. The aim of the thesis is to fabricate silk composite films in whichsilk microfibers are randomly orientated. The composite films are expected to havesuperior mechanical and biological properties to the pure silk films, thus holding promisein simulate the layer structure of knee joint meniscus containing collagen microfibers,which is supposed to provide the function of force-buffering during movement. Thestructure, mechanical properties and biological responses of the composite films werestudied and the feasibility for tissue engineering applications were discussed.In this article, we firstly fabricate silk microfibers by silk hydrolysis in alkali solution,the length of the microfibers is about10-600μm. Through optimizing a series of fabricationconditions can we obtain biggest yield and best uniformity. The preparation method can berepeated. In the tensile properties’ measuring study of composite silk films added silkmicrofibers with different proportion, we optimized the preparation methods andconditions of composite silk films. The film-forming effect by add30wt%glycerol is wellthan other insoluble processing method, such as annealing in water, treating in methanoland ultrasonic. We measured the stress dispersion effect of composite silk films bybursting strength experiment and compared with pure silk fibroin films. The compositefilms added1wt%microfibers is superior to the other proportions on microstructure.Microfibers evenly dispersed in the composite silk film. On mechanical properties, thetensile strength reach10.5MPa and the elongation reach56.7%. The tensile propertiesconform to requirements of meniscus surface collagen microfibers layer. Through infrared spectrum, X-ray diffraction, differential thermal analysis to prove that adding microfibersdo not have a significant impact on properties of composite silk films. Excellentbiodegradability and biocompatibility were proved by enzymatic degradation andcytoactive test. The composite silk films containing silk microfibers can be used assubstitute of collagen microfibers layer that plays a role of buffer for artificial constructionof meniscus.This study integrated the silk fibroin microfibers and film into one system. The studylaid a good foundation for artificial structuring meniscus hierarchical structure and theresearch of other engineering repairing materials.