Peptide decorated demineralized dentin matrix with enhanced bioactivity, osteogenic differentiation via carboxymethyl chitosan

Objectives To improve the biocompatibility and osteogenic activity of demineralized dentin matrix (DDM) by grafting peptides on its surface. Methods DDM was obtained by pulverizing extracted human teeth that had been systematically demineralized and dried. Four groups of materials were evaluated: DDM, DDM/carboxymethyl chitosan (CMC), DDM/CMC/bone forming peptide-1 (BFP-1), and blank. X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and fluorescence localization were used to characterize the surface of the DDM materials. Cell viability was assessed using a CCK8 assay, scanning electron microscopy (SEM) and in vitro osteogenesis was analyzed using real-time RT-PCR (RT-qPCR) and Alizarin red and alkaline phosphatase staining. Three different materials were implanted into mandibular bone defects in rats. After 8 weeks, bone regeneration was assessed by histomorphometry of HE-stained slides. Results FT-IR, XPS, and fluorescence microscopy demonstrated that the DDM surfaces were successfully modified with BFP-1. The CCK8 assay indicated that the proliferation of cells is higher on the DDM/CMC/BFP-1 material than on DDM or DDM/CMC (P < 0.05). Cells were more likely to adhere to DDM/CMC/BFP-1, as observed by SEM. Greater in vitro osteogenesis was observed in the DDM/CMC/BFP-1 group which displayed stronger alkaline phosphatase activity, more alizarin red-stained nodules, and higher target gene expression, as detected by RT-qPCR (P＜0.05). HE staining of in vivo explants indicated that greater quantities of new bone had formed in the DDM/CMC/BFP-1 group. Significance Compared with DDM, DDM/CMC/BFP-1 exhibited superior biocompatibility and osteogenesis, using a method of surface modification that has great potential for future clinical use.