Eco-friendly synthesis of dual-layer coated cerium oxide nanoparticles and holmium-substituted hydroxyapatite/polyacrylic acid composite on titanium implants for biomedical applications

Abstract

This study presents an eco-friendly approach to synthesizing a dual-layer coated cerium oxide nanoparticles (CeO₂NPs) and holmium-substituted hydroxyapatite/polyacrylic acid (CeO₂NPs/nHo-HAp/PAA) biocomposite on titanium (Ti) implants for orthopedic applications using electrophoretic deposition. Utilizing biogenic waste-derived precursors, this method offers a sustainable alternative for fabricating multifunctional implant coatings. Structural analysis via XRD confirmed successful CeO₂/nHo incorporation into HAp, while HRSEM revealed a uniform, porous coating beneficial for bone integration. The biocomposite demonstrated superior mechanical strength (360 Hv), improved corrosion resistance in simulated body fluid, and strong antibacterial efficacy against E. coli and S. aureus. Notably, cytotoxicity studies showed potent anticancer activity against osteosarcoma cells (IC₅₀ = 35.27 µg/mL) with minimal toxicity to healthy Vero cells (IC₅₀ = 421.1 µg/mL). Swelling and degradation studies confirmed favourable bioactivity and long term stability. These findings highlight the potential of CeO₂NPs/nHo-HAp/PAA as a sustainable and multifunctional coating for orthopedic implants, enhancing mechanical integrity, antibacterial resistance, and anticancer properties, paving the way for future biomedical applications.