Influence of PRP/GelMA-MAO composite coating on magnesium alloy implants in bone regeneration effect and bio-corrosion properties

The mismatch between the degradation rate of magnesium (Mg) alloy implants and bone regeneration remains a critical challenge in orthopedic applications. This study presented a PRP/GelMA-MAO composite coating on Mg alloy to synergistically address biocorrosion control, antibacterial efficacy, and bone regeneration. By integrating micro-arc oxidation (MAO) with platelet-rich plasma (PRP)-loaded gelatin methacrylate (GelMA), the composite coating achieved multifunctionality. Incorporation of Ag+ ions during MAO endowed broad-spectrum antibacterial activity, achieving 95.1 % and 93.8 % inhibition rates against E. coli and S. aureus, respectively. PRP enhanced GelMA adhesion to MAO, forming a bioactive coating that promoted osteogenic differentiation of BMSCs and accelerated new bone formation in vivo (19.55 % increase in BV/TV at 28 days). The addition of PRP enhanced the adhesion of GelMA to the MAO coating, significantly slowed down the degradation of the implant, and increased the coating impedance to 1.58 × 107 Ω cm2. These findings demonstrate that the PRP/GelMA-MAO coating effectively balances degradation kinetics with bone healing, offering a promising strategy for clinically viable biodegradable Mg implants.