Bio-inspired calcium silicate–gelatin bone grafts for load-bearing applications

Bio-inspired calcium silicate–gelatin composites with high strength were prepared through a simple pressing–hydrothermal method for load-bearing applications. The phase composition, morphology, and mechanical properties, including the in vitro fatigue behavior, were evaluated. Additionally, in vitro tests were conducted to investigate the biocompatibility of the composites. The results showed that gelatin was dispersed uniformly in the calcium silicate phase and that there was no phase separation between the two phases. Among the composites studied, the 10 wt% gelatin-containing calcium silicate not only exhibited the maximum value of the compressive strength (141.7 MPa), which is strong enough to be used in load-bearing sites of bone tissue, but also had a higher Weibull modulus, indicating a more uniform strength distribution and higher structural reliability. The stability of the composites was affected by in vitro cyclic loading. The presence of gelatin provided a favorable environment for osteoblast-like cells, resulting in a larger degree of cell proliferation, cell differentiation and mineralized tissue formation compared to the control without gelatin. Based on the above results, the bio-inspired calcium silicate–gelatin composites, in particular that containing 10 wt% gelatin, with high initial strength may be an acceptable bone graft substitute as a candidate for load-bearing tissue repair.