Silver-Doped Mesoporous Calcium Phosphate for Controlled Amoxicillin Delivery and Modulation of Osteoblast-like Cell...

Background: Calcium phosphate (CaP)-based materials are widely used for bone defect repair, but their clinical utility is often limited by insufficient antibacterial activity and a lack of controlled drug-release capability. To address this gap, the present study investigates whether silver doping can simultaneously enhance the microstructural properties of mesoporous CaP and modulate its capacity to deliver amoxicillin in a controlled manner, thereby combining osteoconductive, antibacterial, and antibiotic-delivery functions in a single platform. Methods: Mesoporous CaP was synthesized via the polymer sacrificial method and doped with silver at two concentrations (0.5 and 1.0 wt%), both with and without amoxicillin loading, to isolate the individual and combined effects of silver and antibiotic incorporation. The resulting formulations were characterized by XRD, FTIR, SEM, and BET to establish structure-property relationships linking silver content to physicochemical and microstructural features, while their functional performance was assessed through amoxicillin release in PBS over 672 h and through biocompatibility testing on MG-63 osteosarcoma cells via MTT assay at 48, 72, and 120 h. Results: Silver incorporation was found to improve the microstructural properties of the mesoporous CaP and to progressively reduce cumulative amoxicillin release, from approximately 45% in undoped CaP to about 20% at the highest silver content, indicating that silver doping enables tunable, sustained drug release. This modulation of release was accompanied by a favorable biological profile: at 48 h, most formulations showed only moderate effects on MG-63 viability, with comparable IC₅₀ values across groups, while cytotoxicity declined and cell viability increased with longer incubation, reaching the highest proliferation at 120 h for all silver/amoxicillin-containing formulations. Conclusions: Together, these results demonstrate that silver doping does not compromise, and may enhance, the biocompatibility of mesoporous CaP even as it extends antibiotic release. This combination of tunable drug delivery, improved microstructure, and time-dependent biocompatibility positions silver-doped mesoporous CaP as a promising multifunctional platform for antibiotic delivery in bone regenerative medicine.