Plasma-sprayed 45S5-bioactive glass coating provides superior anti-biofilm activity compared to hydroxyapatite coating while maintaining host cell cytocompatibility and antibacterial immune activation

Periprosthetic joint infections (PJIs) are a major complication in joint arthroplasty, leading to higher mortality, poorer outcomes, and increased failure rates in revision surgeries. Revision challenges include patient risk factors, bacterial resistance, and the need for implants that combine biological integration with antibacterial effects. The 45S5-bioactive glass (BG), with its unique osseointegration and antibacterial properties, shows promise over hydroxyapatite (HA), though its high-temperature crystallization limits the appropriate coating technologies. Using atmospheric plasma spraying (APS) with controlled thermal exposure, we successfully applied coatings of Ti-6Al-4V alloys with either HA or BG, while preserving bioactivity and mechanical properties of the BG coating. This study compared HA and BG coated Ti-6AI-4 V discs in terms of cytocompatibility, effect on biofilm formation and macrophage immune response. In doing so, we demonstrated that both coatings showed comparable attachment and viability of human bone marrow stromal cells (BMSC). We found a significant reduction in biofilm formation of Staphylococcus epidermidis (SE) on the BG coatings, while a pro-inflammatory macrophage activation by bacterial colonization and biofilm formation was preserved. Overall, our study shows that BG exhibits the same properties as HA regarding BMSC attachment and survival, whereas it is superior regarding its anti-biofilm characteristics further allowing for macrophage immunocompetence against bacterial colonization. Therefore, incorporating BG coated implants into revision joint arthroplasty has the potential to enhance and advance current coating strategies by providing a multifunctional approach that combines osteoconductive and antibacterial properties. • Atmospheric plasma spraying (APS) enables the successful deposition of 45S5 bioactive glass coatings on Ti-6Al-4V alloys • 45S5 bioactive glass coatings exhibit cytocompatibility with human bone marrow stromal cells comparable to that of state-of-the-art hydroxyapatite coatings • 45S5 bioactive glass coatings significantly reduce Staphylococcus epidermidis biofilm formation compared to conventional hydroxyapatite coatings • 45S5 bioactive glass coatings promote a pro-inflammatory and antibacterial macrophage polarization upon Staphylococcus epidermidis colonization • 45S5 bioactive glass coatings represent a promising multifunctional alternative to hydroxyapatite coatings for revision joint arthroplasty