Biogenic nanohydroxyapatite derived from Channa striata fish bones using alkaline hydrolysis and calcination

Nanohydroxyapatite (nHA) derived from natural resources is an environmentally sustainable alternative to synthetic HA for biomedical applications. In this study, nHA was synthesized from Channa striata fish bones via a modified two-step alkaline hydrolysis process followed by calcination at 550°C. The physicochemical and structural properties of the material were characterized via Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy with energy-dispersive X-ray spectroscopy, transmission electron microscopy, Brunauer–Emmett–Teller analysis, particle size analysis, and thermogravimetric analysis. Functional groups typical of hydroxyapatite, including phosphate, hydroxyl, and carbonate groups, were identified, and X-ray diffraction confirmed a pure crystalline apatite phase with a Ca/P ratio of 1.71, closely matching the stoichiometry of stoichiometric hydroxyapatite. Morphological evaluation revealed rod-shaped nanoparticles of 20–80 nm, and surface analysis revealed nanoscale features with reduced agglomeration following calcination. Thermogravimetric analysis confirmed the complete removal of organic matter at 550°C. Compared with conventional high-temperature calcination methods, the proposed synthesis route requires lower thermal input while maintaining crystallinity and structural stability. These findings demonstrate the potential of Channa striata fish bones as a promising sustainable precursor for the production of high-quality nHA, highlighting their sustainability as a material for dental and biomedical applications.