Biomimetic mineralized collagen scaffolds enhancing odontogenic differentiation of hDPSCs and dentin regeneration through modulating mechanical microenvironment

Dentin regeneration is a huge challenge because of its complicated structure and the shortage of odontoblasts. Unlike in vitro remineralization of dentin through supersaturation of calcium phosphate, the materials of mineralized collagen scaffolds could recruit the human dental pulp stem cells (hDPSCs) and induce their differentiation in vivo and achieve dentin repair. Inspired by the biomineralization of dentin, herein, mineralized collagen fibrils with various mineralization degrees and mechanical properties were prepared through biomolecule hyaluronic acid (HA) modification, and first time find the mechanical properties have a positive correlation with mineralization degree. When 1.2 mg/mL HA was used to modification, the mineralized HA-modified collagen scaffolds (HA-MCS) with similar modulus and stiffness to that of natural dentin could be obtained. Furthermore, testing ALP activity and alizarin red S staining experiments confirmed the HA-MCS with a biomimetic mechanical microenvironment could enhance the proliferation and differentiation of hDPSCs. Additionally, in vivo experiments performed on the beagle model further proved this point that HA-MCS with a biomimetic mechanical microenvironment could promote dentin regeneration. These results not only elucidate that the modulation of mechanical properties of biomaterials could enhance the proliferation and differentiation of stem cells, but also provide a strategy for hard tissue regeneration.