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

Nanohydroxyapatite (nHA) derived from natural resources has emerged as a sustainable alternative to synthetic nHA for biomedical applications. In this study, nHA was synthesized from Channa striata fish bones using a modified two-step alkaline hydrolysis followed by calcination at 550 °C. The structural and physicochemical properties of the material were characterized using 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 (PSA), and thermogravimetric analysis. The results confirmed the formation of phase-pure crystalline hydroxyapatite with characteristic phosphate, hydroxyl, and carbonate functional groups. The Ca/P ratio (1.71) was close to the stoichiometric value, indicating high compositional purity. Morphological analysis revealed rod-shaped nanoparticles with an average size of ~ 60 nm, while PSA indicated a broader size distribution due to particle agglomeration. The applied calcination temperature effectively removed organic components while preserving nanoscale structural features. In addition, antibacterial activity against Streptococcus mutans was demonstrated, suggesting potential for dental applications. These findings indicate that the proposed synthesis approach enables the production of phase-pure biogenic nHA with controlled nanoscale characteristics under moderate calcination conditions, highlighting Channa striata fish bones as a sustainable and cost-effective precursor for biomedical and dental materials.