Extraction and degradation rate analysis of calcium phosphate from diverse fish Bones: A comparative study

Converting waste fish bones into bioactive materials presents an innovative and eco-friendly approach to materials science. Fish bones, often discarded as waste in the seafood industry, are rich in calcium (Ca) and phosphorous (P), making them ideal precursors for Calcium phosphate (CaP) materials. In this study, different kinds of CaP materials were successfully extracted from diverse fish bone types like Carp fish (CF), Atlantic bonito (AB) and Gilt-head bream (GB) using a heat treatment method. The extracted white powders were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), Transmission electron microscopy (TEM), and Inductively coupled plasma mass spectrometry (ICP-MS) techniques and the outcomes compared the most popular phase of CaP material like β -tricalcium phosphate (β-TCP) and Hydroxyapatite (HA) which they are synthesized using microwave refluxing equipment. The XRD pattern of the CF sample closely corresponded with the HA phase, while the AB and GB samples aligned with the biphasic calcium phosphate (HA/β-TCP) phase. The FTIR spectra analysis identified the presence of phosphate, hydroxyl, and carbonate groups. The XPS spectra determined the Ca/P ratio to range between 1.32 and 1.57. In vitro degradation studies were performed in phosphate-buffered saline (PBS) at 37 °C over 1, 3, 7, and 14 days. The ion release profiles of Ca²⁺ and P⁵⁺ were monitored, revealing the most significant degradation rate occurred between 7 and 14 days. The highest leaching levels of Ca ions were observed in the AB fish bones, with concentrations reaching approximately 87.35 mg/L after 14 days of immersion. Based on the results, it is concluded that the biphasic calcium phosphate derived from AB, along with its Ca, P, and other minerals content, exhibits a higher degradation rate than other samples. This indicates its potential as a promising bioactive material suitable for use as a bone tissue substitute.