Exploration of microstructural characteristics, mechanical properties, and in vitro biocompatibility of biodegradable porous magnesium scaffolds for orthopaedic implants

Abstract

In this study, porous magnesium (Mg) scaffolds were investigated with varying strontium (Sr) and constant zinc (Zn) concentrations through the powder metallurgy process. All samples were examined at room temperature to evaluate their microstructure, mechanical and in-vitro degradation behavior, and biological properties. Results indicated that the addition of Sr was associated with fine average grain size, increased mechanical strength, and a decreased corrosion rate. All samples show small isolated and open interconnected pores (porosities: 18-30%, pores: 127-279 µm) with a suitable surface roughness of less than 0.5 µm. All samples have mechanical properties that are hemocompatible and closer to those of natural bone. Mg-4Zn-2Sr has the highest hardness (102.61 ± 15.1 HV) and compressive strength (24.80 MPa) than Mg-4Zn-0.5Sr (85 ± 8.5 HV, 22.14 MPa) and Mg-4Zn-1Sr (97.71 ± 11.2 HV, 18.06 MPa). Immersion results revealed that samples in PBS solutions have excellent degradability properties, which makes them a promising biodegradable material for orthopaedic applications. The scaffold with the highest Sr concentration shows the best optimized mechanical and degradation behavior out of the three scaffolds, with a 2.7% hemolysis rate.