Preparation And Characteristics Of Gradient Silk Fibroin/Hydroxyapatite Porous Composites

The gradient SF/HA porous composite used for the scaffold of the cartilage-bone tissueregeneration was prepared with silk fibroin (SF) powder and hydroxyapatite (HA) powdercomposited which obtained by layer-by-layer mould pressing method and NaCl as porogen,Carded on the characteristics of structure and performance and investigated the materialscompared to non-gradient materials.Firstly, the SF powder was obtained by spray drying method, the crystal structure ofwhich was mainly amorphous and mean diameter 296.8 nm. HA powder was obtained byfreeze drying-milling method, and the average diameter of HA was 806.7 nm. The paperresearched how the pore structure parameter was effected by the proportion of HA, SF andNaC1. The result indicated that the porosity, density and average pore size of non-gradientcomposites by mould pressing method were increasing as the proportion of HA/SF andNaCl increasing.Secondly, the linear gradient SF/HA porous composites which pore structure could beadjusted was prepared by layer-by-layer mould pressing method, and characterized byElectron Microprobe, EDS, XRD, SEM and FT-IR. It indicated that the distribution of SFand HA presented gradient along thickness direction of the materials, and the pore of thegradient materials was interconnected when the content of NaCl was up to 600ï¼….Lastly, comparing the structure and mechanics of the gradient SF/HA composites andnon-gradient materials, it indicated that the flexure break energy and compress breakenergy of the gradient SF/HA surpassed the SF/HA non-gradient composites', and it waseasier to formed interconnected pore structures in the gradient SF /HA than in SFnon-gradient materials when NaCl particles were added.