Enhanced corrosion resistance, antibacterial activity and biocompatibility of gentamicin-montmorillonite coating on Mg alloy- in vitro and in vivo studies

Implant-associate infection (IAI) is a major cause of failure of bone implant materials, and one of the significant challenges in clinical managements. A synergistic coating strategy combining montmorillonite (MMT) sustained release, adsorption of bacteria and gentamicin (GS) bactericidal is proposed herein to tackle infection issues. Surface morphology, microstructure and chemical composition of the samples were investigated using SEM, XRD, FT-IR and XPS. Electrochemical experiments and immersion experiments reveal that corrosion resistance of Mg samples with GS/MMT coatings was higher than that of bare Mg alloy substrate in DMEM solution. In vitro studies demonstrated that the GS/MMT coating had a significant inhibitory effect on Escherichia coli ( E. coli) and Staphylococcus aureus ( S. aureus). The viability of MC3T3-E1 cells was 92.7% after a co-culturing for 72 h. After a subcutaneous transplantation of 90 days, the survival rate was 100% for GS/MMT-coated Mg alloy specimens with no infection at the implantation sites and no toxic damage to liver, kidney and local muscles pathological sections. This study provides a novel method for the preparation of sustained-release antimicrobial coatings on biodegradable Mg alloys as promising candidates for orthopedic implant materials. (c) 2021 Published by Elsevier Ltd on behalf of Chinese Society for Metals.

Automated summary

This study proposes a synergistic coating strategy that combines sustained release of montmorillonite, bacteria adsorption, and gentamicin bactericidal to address implant-associated infections. In vitro experiments demonstrate the significant antibacterial effects of the coating on Escherichia coli and Staphylococcus aureus. Moreover, the transplanted Mg alloy specimens with the coating showed no infection at the implantation sites and no toxic damage to the liver, kidney, and local muscles.