This study investigated the physicochemical properties of hydroxyapatite (HA) synthesized from Polymesoda erosa shells and the antibacterial potential of HA combined with zinc oxide (ZnO). Polymesoda erosa shells were calcined to produce calcium oxide (CaO), which was subsequently used to synthesize HA via precipitation. Hydroxyapatite (HA) was synthesized and subsequently characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The results indicated high crystallinity and a calcium-to-phosphorus (Ca/P) molar ratio ranging from 1.52 to 1.69, closely resembling the composition of natural bone. At higher sintering temperatures, partial transformation to β-tricalcium phosphate (β-TCP) was observed, enhancing bioactivity. The antibacterial properties were assessed using the disk diffusion technique. While pure hydroxyapatite (HA) exhibited no observable inhibition zones, the addition of 1.5% zinc oxide (ZnO) significantly enhanced antibacterial performance, as evidenced by inhibition zones measuring 0.96 mm against Staphylococcus aureus and 0.62 mm against Escherichia coli. These results suggest that ZnO incorporation effectively imparts antibacterial activity to the HA matrix. The results highlighted the potential of Polymesoda erosa-derived HA-ZnO composites as sustainable biomaterials for regenerative bone applications. Their enhanced bioactivity and antibacterial properties make them promising candidates for advancing suggest their promise in advancing bone tissue engineering and addressing infection-related challenges.

Keywords: Polymesoda erosa, Hydroxyapatite, Zinc oxide, Composite, Antibacterial.