Abstract
Synthetic biomaterials are widely used as bone graft substitutes, but their osteogenic capacity is limited as they lack osteogenic growth factors. This study aimed to enhance the osteogenesis of a novel hydroxyapatite/aragonite (HAA) biomaterial by incorporating decellularized bone matrix and bone morphogenetic protein (BMP)-2 and BMP-7 (BMP-2/7). Human umbilical mesenchymal stem cells (MSCs) were able to proliferate and differentiate on HAA. HEK-293T cells exogenously expressing BMP-2/7 successfully secreted BMP-2/7, which was assessed by enzyme-linked immunosorbent assay. By establishing a co-culture of MSCs with HEK-293T cells expressing BMP-2/7, we successfully created an artificial allograft that integrates both synthetic biomaterials and functional organic components, offering the potential to enhance osteogenesis. The decellularized (by freeze/thawing) functional HAA was implanted between the tibia and anterior tibialis muscle in murine models and assessed the induced bone formation via micro-computer tomography, histology, and osteogenic markers mRNA expression by a reverse transcription-quantitative polymerase chain reaction. A significant increase in new bone formation was seen in the functional HAA implanted group. In conclusion, this study revealed that bone formation following the HAA implantation can be enhanced by a functional decellularized matrix, comprising BMP-2/7, via in vitro tissue engineering using MSCs and HEK-293T cells expressing BMP-2/7.