Bio-based composite membranes from fish scales: A novel approach to harnessing collagen and hydroxyapatite for tissue engineering applications

Fish scales, a by-product of the fishing industry, have been identified as a potential source of hydroxyapatite and collagen due to their inherent composition. The present study aims to develop a bio-based membrane from fish scales as a raw material, evaluating its suitability for tissue engineering applications. The characterisation of the resulting membranes was performed by infrared spectroscopy, which allowed the identification of peaks corresponding to the vibrational modes of the amides present in collagen. The presence of hydroxyapatite was confirmed by X-ray diffraction, the results of which were in agreement with the ICDD 009–0431 standard. The collagen denaturation temperature (70 °C) was determined using differential scanning calorimetry. Furthermore, the mechanical properties were evaluated by uniaxial tensile tests, following the standards of ASTM-D1708–96, and the Young's moduli were obtained as 7179 ± 77 kPa in dry conditions and 760 ± 133 kPa in wet conditions. In tests with human gingival fibroblasts, the fish scale-derived membranes showed higher cell viability and significantly higher proliferation rates compared to the commercial type I collagen membrane used as a control (Matrixflex™, obtained from highly purified porcine peritoneum), highlighting the potential of fish scale-derived membranes as bio-based composite materials.