Bone forming ability of recombinant human collagen peptide granules applied with β‐tricalcium phosphate fine particles

Recombinant human collagen peptide, developed based on human collagen type I, contains an arginyl‐glycyl‐aspartic acid (RGD)‐rich motif to enhance cell behavior and is anticipated as a xeno‐free polymer material for use in tissue engineering. We fabricated granules containing recombinant human collagen peptide (RCP) applied with beta‐tricalcium phosphate fine particles (RCP/β‐TCP) as bone filling scaffold material and assessed the bone forming ability of RCP/β‐TCP. Recombinant peptide was thermal crosslinked and freeze‐dried to prepare RCP. An aqueous dispersion of β‐TCP fine particles was added to RCP to obtain RCP/β‐TCP. Subsequently, RCP/β‐TCP were characterized using scanning electron microscopy (SEM), energy dispersive X‐ray spectrometry (EDX), and cell culture assessments. Furthermore, RCP/β‐TCP were implanted into rat cranial bone defects for radiographic and histological evaluations. In SEM and EDX analyses of RCP/β‐TCP, β‐TCP particles dose‐dependently covered the surface of RCP. Cell culture tests showed that RCP/β‐TCP remarkably promoted proliferation and mRNA expression of various genes, such as integrin β1 and osteogenic markers, of osteoblastic MC3T3‐E1 cells. Histomorphometric assessment at 4 weeks showed that RCP/β‐TCP significantly promoted new skull bone formation compared to RCP (p