An oral environmental responsive complex with mineralisation-antibacterial dual-activities for the prevention and treatment of early dental caries

Objective This study aimed to develop an oral environment-responsive complex with mineralisation-antibacterial dual-activities for preventing and treating early dental caries. Methods The complex was synthesized with phosphorylated starch serving as a template to stabilize calcium phosphate prenucleation clusters (CaP-PNCs) and silver nanoclusters (AgNCs). The binding properties of the complex on human enamel were evaluated using confocal laser scanning microscopy (CLSM). Antibacterial efficacy against Streptococcus mutans , including both planktonic bacteria and biofilms, was assessed through colony counting, scanning electron microscopy (SEM), and live/dead staining. Remineralization effects on artificially demineralized enamel were analyzed using SEM, CLSM, and energy-dispersive X-ray spectroscopy (EDS). Cytotoxicity on MC3T3 cells was tested using CCK-8 assays. Results The CaP-PNCs/AgNCs complex demonstrated strong binding to human enamel. In the presence of α-amylase, the complex exhibited potent antibacterial effects, achieving a 90% reduction in planktonic Streptococcus mutans viability and and significantly disrupted biofilms. Remineralization assays showed a 70-100 μm hydroxyapatite layer resembling natural enamel in structure and composition. Notably, the complex maintained effective remineralization capabilities even under cariogenic bacterial challenge. Cytotoxicity evaluations on MC3T3 cells indicated no adverse effects on viability. Conclusion This complex enables targeted antibacterial action and biomimetic mineralization through responsively release of AgNCs and CaP-PNCs in oral environment, simultaneously addressing biofilm disruption and promoting enamel regeneration for the treatment of early caries. Clinical Significance The oral environmental responsive design provides a minimally invasive strategy to repair demineralized enamel while suppressing pathogenic biofilms, bridging non-invasive prevention and structural restoration in caries management.