Bioglass-Doped Hydroxyapatite Sol-Gel Coatings Enhance Curcumin Release and Biological Performance of Ti6Al4V Orthopedic Implants

Curcumin is a bioactive polyphenol exhibiting antibacterial and antiosteosarcoma properties; however, its clinical translation is constrained by poor aqueous solubility and low bioavailability. In this work, bioglass (BG) was incorporated into sol-gel-derived hydroxyapatite (HA) coatings on Ti6Al4V substrates to enable compositional control over curcumin release and biological response. HA coatings containing 1, 2.5, and 5 wt % BG were fabricated to investigate the influence of BG content on release behavior and multifunctional performance. Increasing BG content enhanced curcumin release by up to 1.4-fold at pH 5.0 and 1.6-fold at pH 7.4 relative to HA controls, consistent with increased coating degradation and microstructural changes associated with increasing BG content. The release profiles exhibited an initial burst followed by an asymptotic plateau, consistent with sustained release from the coating. BG-containing coatings also promoted osteoblast viability, increasing metabolic activity by up to 70% with BG alone and up to 86% in BG-containing curcumin-loaded coatings. In contrast, curcumin selectively reduced osteosarcoma cell viability by 67% after 11 days, accompanied by increased reactive oxygen species generation and mitochondrial dysfunction, suggesting oxidative stress-mediated cytotoxicity. Antibacterial testing demonstrated up to 78% reduction in Staphylococcus aureus viability after 72 h. These results demonstrate that compositional tuning of BG within HA coatings enables simultaneous control of drug release and selective biological responses, providing a multifunctional platform for orthopedic implants that supports osteoblast activity while mitigating infection and tumor recurrence risks.