Microalloy Mg-based degradation implant for intra-osteal fixation

Abstract

The bottleneck for Mg-based degradable implants lies in the mismatching relationship between mechanical properties and degradable rate, resulting in the rapid failure during the in-vivo degradable process and potential toxic role. Herein microalloy-conception has been involved to rectify the equilibrium effects among several aspects. Microstructure, mechanical properties, degradable properties and in-vitro/in-vivo biocompatibility properties of as-extruded pure Mg, Mg-0.15Ca, and Mg-0.15Ca-0.10Mn samples have been investigated. The results show that the Mg-0.15Ca-0.1Mn alloy exhibits a high yield strength (110 MPa) and a low degradable rate (0.82 mm/y). Attractively, the mechanical integrity has been remained in Mg-0.15Ca-0.1Mn alloy after 14 weeks in the rat femoral mode, and a homogenous degradable rate with 0.92 mm/y has been confirmed, which is basically equivalent to the in vitro value. Simultaneously, the low concentration of ions also reveals satisfactory biocompatibility equal to pure Mg, based on organ function and pathological morphology. Our findings reveal that microalloy paves a possible route to design high performance Mg-based intra-osteal fixation implants, resolving the contradictions among the degradable requirements under different body environments.