Boron nitride nanosheet-enhanced coatings for preventing biofilm formation on magnesium implants

As a novel antimicrobial biomaterial, boron nitride nanosheets (BNNS) exhibit a broad antimicrobial spectrum and minimal resistance, offering promising clinical and translational potential. However, research on the antimicrobial and osteogenic properties of BNNS in orthopedic applications is still in its early stages, with the long-term effects on human use remaining unclear. In this study, a BNNS-based composite coating was fabricated on a magnesium substrate using micro-arc oxidation (MAO) and electrophoretic deposition (EPD). The coating, incorporating BNNS and chitosan (CS), aimed to enhance the antibacterial properties of magnesium and prevent bacterial biofilm formation. Surface characterization confirmed a uniform coating rich in BNNS, which improved corrosion resistance and reduced degradation in simulated body fluid (SBF). The BNNS@CS/MAO coating demonstrated superior surface integrity, uniformity, and significant antibacterial activity, particularly against S. aureus. Biofilm assays and crystal violet staining further confirmed its effectiveness in reducing bacterial adhesion and biofilm formation. Molecular dynamics simulations revealed that BNNS disrupt bacterial membranes by perpendicularly penetrating lipid bilayers, contributing to their bactericidal effects. These findings underscore the potential of BNNS-based coatings as a promising strategy to enhance the longevity and performance of magnesium-based implants in biomedical applications.