Hydroxyapatite-Coated Ti6Al4V With Liposome-Encapsulated Gooseberry Extract for Orthopedic Applications

Abstract

This study investigates gooseberry (Phyllanthus emblica) extract (GB) as a bioactive additive to provide antibacterial activity and activity against osteosarcoma cells in hydroxyapatite-coated Ti6Al4V implants while maintaining osteoblast cytocompatibility. Aqueous extraction of GB yields a multicomponent formulation containing hydrophilic bioactive constituents that are prone to rapid release and poor retention under physiological conditions, thereby limiting their utility in implant-based delivery systems. To address this limitation, GB was encapsulated within liposomes to mitigate burst release and enable sustained delivery from implant surfaces. When incorporated onto plasma-sprayed hydroxyapatite-coated Ti6Al4V substrates, liposomal encapsulation reduced burst release within the first 48 h by 18% at pH 5.0 and 27% at pH 7.4. The formulation reduced osteosarcoma cell viability by 58% ± 7% after 11 days and decreased Pseudomonas aeruginosa and Staphylococcus aureus viability by 78% ± 3% and 45% ± 6%, respectively, within 48 h. Importantly, the system exhibited no cytotoxic effects toward osteoblasts, as demonstrated by MTT cell viability assays. In vivo evaluation of GB-treated implants after 6 weeks further demonstrated no adverse effect on early bone formation, with histological analysis showing a trend toward increased bone formation relative to control implants. These results demonstrate the feasibility of stabilizing and delivering a complex, hydrophilic natural extract from implant surfaces using liposomal encapsulation while maintaining osteoblast compatibility and without adversely affecting early bone formation in vivo.