Biomaterial availability of magnesium substituted beta-tricalcium phosphate converted from sea urchin <i>Tripneustes gratilla</i> shell

Sea urchin Tripneustes gratilla is one of the valuable fishery products in Taiwan. The edible part of sea urchin is about 10% and the rest is regarded as waste. In this study, sea urchin shell was used here as an ingredient to synthesize magnesium substituted beta-tricalcium phosphate (β-TCMP). Shell powder of the echinoid Tripneustes gratilla was converted by hydrothermal reaction at 180°C for 24 h (referred as SU-180-24 product), and calcinated into tablet at 800°C for 4 h to form the target ingredient (SU-800-4 product). Then these products were tested for chemical composition analysis and bioassays. These products are confirmed to be rich in magnesium and constitute as β-TCMP. Results from bioassays showed that SU-180-24 and SU-800-4 products increased cell viability in human osteosarcoma cell (MG-63). Alkaline phosphatase (ALP) activity of MG-63 cell cultured with SU-800-4 tablet also showed significant increase when compared to commercial β-TCMP. It indicated that sea urchin’s β-TCMP materials including SU-180-24 and SU-800-4 products exhibited the potential for applying as the bone graft material.