Effect of compression ratio on microstructure evolution of Mg−10%Al−1%Zn−1%Si alloy prepared by SIMA process

A new Mg−10%Al−1%Zn−1%Si alloy with non-dendritic microstructure was prepared by strain induced melt activation(SIMA)process.The effect of compression ratio on the evolution of semisolid microstructure of the experimental alloy was investigated.The results indicate that the average size ofα-Mg grains decreases and spheroidizing tendency becomes more obvious with the compression ratios increasing from 0 to 40%.In addition,the eutectic Mg2Si phase in the Mg−10%Al−1%Zn−1%Si alloy transforms completely from the initial fishbone shape to globular shape by SIMA process.With the increasing of compression ratio,the morphology and average size of Mg2Si phases do not change obviously.The morphology modification mechanism of Mg2Si phase in Mg−10%Al−1%Zn−1%Si alloy by SIMA process was also studied.

Improved the biocompatibility of cancellous bone with compound physicochemical decellularization process

Due to the unique microstructures and components of extracellular matrix(ECM),decellularized scaffolds had been used widely in clinical.The reaction of the host toward decellularized scaffolds depends on their biocompatibility,which should be satisfied before applied in clinical.The aim of this study is to develop a decellularized xenograft material with good biocompatibility for further bone repair,in an effective and gentle method.The existing chemical and physical decellularization techniques including ethylene diamine tetraacetic acid(EDTA),sodium dodecyl sulfate(SDS)and supercritical carbon dioxide(SC-CO2)were combined and modified to decellularize bovine cancellous bone(CB).After decellularization,almost 100%of A-Gal epitopes were removed,the combination of collagen,calcium and phosphate was reserved.The direct and indirect contact with macrophages was used to evaluate the cytotoxicity and immunological response of the materials.Mesenchymal stem cells(MSCs)were used in the in vitro cells’proliferation assay.The decellularized CB was proved has no cytotoxicity(grade 1)and no immunological response(NO,IL-2,IL-6 and TNF-α secretion inhibited),and could support MSCs proliferated continuedly.These results were similar to that of commercial decellularized human bone.This study suggests the potential of using this kind of combine decellularization process to fabricate heterogeneous ECM scaffolds for clinical application.