[Research on the modification of poly(amido amine) with poly peptides to induce enamel remineralization]

Objective: To develop N-terminal 15-peptide of statherin (SN15)-poly(amido amine) (PAMAM) by grafting the statherin-derived peptide SN15 onto a PAMAM dendrimer for enhanced tooth adsorption and remineralization, and to evaluate its efficacy in promoting the remineralization of demineralized enamel in a simulated oral environment. Methods: SN15 peptides were grafted onto the surface of PAMAM by mercapto-Michael addition reaction. The adhesion force and adsorption capacity of SN15-PAMAM and PAMAM towards hydroxyapatite (HA) were compared and investigated using atomic force microscopy (AFM), among other techniques. The ability of enamel remineralization induced by SN15-PAMAM in simulated saliva environment and under simulated oral acid shock were studied by a coating method. The blank control group was treated with an equal volume of deionized water. The SN15-PAMAM or PAMAM rinse groups were treated with SN15-PAMAM or PAMAM, followed by phosphate-buffered saline rinsing. The nano-amorphous calcium phosphate (NACP) group was treated by NACP only. Each group had a sample size of 6. Transverse microradiography (TMR) and other assays were performed. Results: AFM results showed that the adhesion force between the SN15-PAMAM group and the HA surface was (9.3±1.5) nN, which was significantly higher than that of the PAMAM group [(2.8±1.3) nN] (P<0.05). In the simulated saliva environment for inducing enamel remineralization, the SN15-PAMAM group demonstrated the most significant recovery of surface hardness, reaching 74.48%, which was superior to the 40.72% recovery observed in the PAMAM group. Under simulated oral acid shock, the difference between the two groups became even more pronounced: the hardness recovery for SN15-PAMAM was 61.83%, while for PAMAM it was only 25.19%. Under simulated daily oral acid challenge conditions, SN15-PAMAM and NACP exhibited a synergistic effect. TMR results revealed that the lesion depth in the SN15-PAMAM+NACP group was (38.95±2.70) μm, significantly lower than that in the SN15-PAMAM group [(74.81±3.10) μm], the NACP group [(75.56±3.66) μm], and the blank control group [(106.40±2.35) μm] (all P<0.05). Conclusions: PAMAM, modified with the statherin-derived peptide SN15, enhances enamel remineralization by improving its adsorption to the enamel surface.