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/beta-TCP) as bone filling scaffold material and assessed the bone forming ability of RCP/beta-TCP. Recombinant peptide was thermal crosslinked and freeze-dried to prepare RCP. An aqueous dispersion of beta-TCP fine particles was added to RCP to obtain RCP/beta-TCP. Subsequently, RCP/beta-TCP were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX), and cell culture assessments. Furthermore, RCP/beta-TCP were implanted into rat cranial bone defects for radiographic and histological evaluations. In SEM and EDX analyses of RCP/beta-TCP, beta-TCP particles dose-dependently covered the surface of RCP. Cell culture tests showed that RCP/beta-TCP remarkably promoted proliferation and mRNA expression of various genes, such as integrin beta 1 and osteogenic markers, of osteoblastic MC3T3-E1 cells. Histomorphometric assessment at 4 weeks showed that RCP/beta-TCP significantly promoted new skull bone formation compared to RCP (p < 0.05) and control (no application) (p < 0.01). Accordingly, these findings suggest RCP/beta-TCP possess bone forming capability and would be beneficial for bone tissue engineering therapy.