DEVELOPMENT OF NOVEL ANTIBACTERIAL BIOACTIVE COATINGS ON MAGNESIUM BASED IMPLANTS TO TREAT INTRA-ARTICULAR FRACTURES

Abstract

Magnesium (Mg) and its alloys have emerged as viable biodegradable materials for orthopedic implants because of their advantageous mechanical compatibility and bioresorbability properties; nevertheless, their rapid corrosion, hydrogen evolution, and infection susceptibility limit their clinical application. In the current study, phosphate coatings were fabricated on pure Mg and AZ31 Mg alloy through a single-step hydrothermal synthesis approach with Ag and Cu being added to improve the antibacterial and corrosion resistance properties. Reaction temperature and an alkaline pH environment were optimized from 125 to 200 °C and 9.0, respectively, for coating nucleation and growth. Structural features were examined by scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis. The electrochemical behavior was evaluated through potentiodynamic polarization and open circuit potential measurements. In vitro degradation was assessed in simulated body fluid (SBF) at 37 °C, and antibacterial performance was determined against Staphylococcus aureus and Escherichia coli using the broth dilution method. From the results obtained, hydrothermal treatment was shown to facilitate the in-situ synthesis of dense magnesium phosphate layers through the dissolution–re-precipitation process, with significant temperature-induced morphology modifications. A highly dense structure free from defects with 98% reduction in the corrosion rate as compared to bare Mg was observed at 150 °C.  AZ31 samples containing 0.05 M% Ag showed the most balanced overall performance. These findings highlight a viable strategy to regulate Mg degradation while imparting antibacterial functionality for biodegradable implant applications.