Functionalized graphene nano-platelet reinforced magnesium-based biocomposites for potential implant applications

Magnesium (Mg) is an attractive candidate for fracture fixation implants due to its bioabsorbability. However, their mechanical properties under load and in biological environments appear to be insufficient, and bacterial biofilm formation may further complicate the situation. In this paper, for the first time, functionalized graphene nanoplatelets (FGNPs) as reinforcement in Mg-3Zn-0.5Zr (ZK30) alloy matrix were homogeneously prepared using semi-powder metallurgy (SPM) method, and subsequently, the composites were prepared using spark plasma processing (SPS). The compressive strength test was performed for different composites before and after immersion in simulated body fluid (SBF). The ZK30/0.5FGNPs composite shows a significantly higher ultimate compressive strength (UCS) compared to the other composites, 285 +/- 11 MPa before and 220 +/- 9 MPa after exposure to the SBF environment, compared to the ZK30 alloys; which shows 195 +/- 8 MPa before and 135 +/- 5 MPa after 14 days of exposure to SBF environment. Furthermore, after evaluating the antibacterial activity, it was proved that adding FGNPs nanofillers to the ZK30 matrix could impressively prevent the growth and colonization of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Cytotoxicity studies also confirm that composites with low amounts of FGNPs do not show cytotoxic behavior against MG63 cells, while higher loadings of FGNPs lead to toxicity. In general, according to this research results, ZK30/0.5FGNPs composite can be used for the application of loaded implants and the treatment of bone infection.