Promotion of Biomimetic Mineralization via Preinfiltration of Mineral Precursors

Intrafibrillar mineralization plays an important role in dentin repair. Current research on intrafibrillar mineralization primarily focuses on the precise positioning of mineral precursors within collagen and the reduction of mineralization time. Inspired by the multifunctionality of noncollagenous proteins (NCPs), we developed a dual-analogue system, 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) followed by 3-(3,4-dihydroxyphenyl)-l-alanine (l-DOPA)-stabilized amorphous calcium phosphate (M + LA), which integrated a nucleation inhibitor l-DOPA and inducer 10-MDP. In this study, we investigated the impact of a preinfiltration strategy using the M + LA system on intrafibrillar mineralization. l-DOPA with a concentration of 250 μg mL-1, acting as a mussel-inspired nucleation inhibitor, was demonstrated to stabilize amorphous calcium phosphate (ACP) precursors within 2 h at 37 °C, with the formed precursors termed "LACP" (l-DOPA-stabilized amorphous calcium phosphate). Numerous LACP precursors were immobilized within collagen via the M + LA system, referred to as "preinfiltration." The M + LA system exhibited no significant cytotoxicity, as evidenced by the biocompatibility evaluation through a modified trans-dentin disk model. Notably, the M + LA preinfiltration strategy significantly reduced intrafibrillar mineralization time to 3 h, superior to that of bare collagen and MDP-modified collagen. Furthermore, the resulting mineralized M + LA-modified collagen achieved functional mechanical properties. Moreover, 10-MDP-Ca nanolayering was generated via a bottom-up approach during the preinfiltration process. This study introduces a preinfiltration strategy for promoting intrafibrillar mineralization, which provides a reference for understanding the mechanism of intrafibrillar mineralization and shows promising clinical application prospects for dentin repair.