Promoting effect of proanthocyanidin-amorphous calcium phosphate nanoparticles on biomimetic mineralization of demineralized dentin

Biomimetic mineralization is a new strategy for dentin repair emerging in the field of minimally invasive dentistry in recent years. However, the degradation of collagen fibrils and the lack of sustained supply of calcium and phosphorus ions are two main limitations during dentin biomimetic mineralization. Herein, by integrating the dual effects of collagen protection and mineralization induction, we proposed a novel nanoscale platform called proanthocyanidin-amorphous calcium phosphate nanoparticles (PA-ACP/NPs), which were solid nanospheres with uniform size and good biocompatibility, and could continuously release Ca and P ions in neutral or weak acidic microenvironment. PA-ACP/NPs effectively decreased the endogenous collagenase activity of demineralized dentin matrix and protected demineralized dentin collagen from degradation. Compared with the control ACP/NPs, PA-ACP/NPs induced nearly complete intrafibrillar mineralization of collagen fibrils and facilitated remineralization of demineralized dentin. As an additive of dental adhesives for the preliminary exploration of clinical application forms, the adhesive containing 20 wt% PA-ACP/NPs induced biomimetic intrafibrillar mineralization within the bonding interface after one and three months. PA-ACP/NPs nanoscale delivery exhibits excellent effects on stabilizing collagen fibrils and provides a long-term supply of mineral ions for dentin biomimetic mineralization, being a promising strategy for dentin biomimetic repair.