Investigation on the microstructure, mechanical properties, in vitro degradation behavior and biocompatibility of newly developed Zn-0.8%Li-(Mg, Ag) alloys for guided bone regeneration.

ABSTRACT

In order to develop a biodegradable guided bone regeneration membrane with the required mechanical properties and high corrosion resistance, Zn-0.8%Li(wt), Zn-0.8%Li-0.2%Mg(wt), and Zn-0.8%Li-0.2%Ag(wt) alloys were cast and hot rolled into 0.1-mm thick sheets. The main secondary phase in Zn-0.8%Li-(Mg, Ag) alloys was the LiZn4 nanoprecipitate. Following the addition of minimal amounts of Mg, the tensile strength of the Zn-0.8%Li-0.2%Mg alloy improved, albeit with a greatly reduced elongation and corrosion resistance. The addition of minimal amounts of Ag refined the microstructure, producing fine equiaxed grains (2.3 µm) in the Zn-0.8%Li-0.2%Ag alloy, and promoted a uniform distribution of LiZn4 nanoprecipitates with increased density and refined size. Therefore, the Zn-0.8%Li-0.2%Ag alloy exhibited optimal tensile strength and the highest corrosion resistance, with its elongation reaching 97.9 ±â€¯8.7%. The corrosion products of Zn-0.8%Li-(Mg, Ag) alloys immersed in Ringer's solution for 35 days mainly consisted of zinc oxide and zinc carbonate. In addition, the cytotoxicity test using L929 cells and the evaluation of bone marrow mesenchymal stem cell proliferation indicated that the Zn-0.8%Li-0.2%Ag alloy had good biocompatibility.