Preparation of porous Zn-Li alloy scaffolds for bone repair and its degradation behavior in vitro and in vivo

Abstract

Through preparing the porous Zn-0.8Li scaffolds with 50–70 % porosity by using NaCl particles as pore-forming agents in the range of 150–350 µm and 350–550 µm with the infiltration casting method, the present study investigated the pore structure, mechanical properties and weight loss in simulated body fluids (SBF), and conducted the cellular activity and in vivo degradation experiments on porous Zn-0.8Li scaffolds before and after chitosan coating treatment. The results showed that the porous samples with small pore size had higher mechanical properties and lower degradation rate. However, with relatively higher average porosity and through-porosity, the porous samples with large pore size showed better pore connectivity, which provided channels for nutrient transport and promoted the lateral growth of internal tissues. In terms of cell experiments, chitosan coated Zn-0.8Li scaffolds with large pore size had better cell activity and adhesion. Since the coating of chitosan inhibited the release of Zn2+ during the implantation of porous Zn-0.8Li scaffolds in vivo, it effectively promoted the growth of new bone tissue around the porous scaffolds, which provided an ideal microenvironment for the adhesion, proliferation and differentiation of MSCS. The results of this study demonstrated the great potential of chitosan coated porous biodegradable Zn-based scaffolds for bone tissue engineering.