Encapsulation of a novel peptide derived from histatin-1 in liposomes against initial enamel caries in vitro and in vivo

Objectives: Biomimetic mineralization mediated by proteins and peptides is a promising strategy for enamel repair, and its specific application model needs more research. In this work, we exploited a liposomal delivery system for a novel peptide (DK5) derived from histatin-1 (DK5-Lips) as a new biomimetic mineralization strategy against initial enamel caries. Materials: and methods: The DK5-Lips was prepared using calcium acetate gradient method and then the in vitro release, salivary stability and cytotoxicity were studied. Initial enamel caries was created in bovine enamel blocks and subjected to pH-cycling model treated with DK5-Lips. Surface microhardness testing, polarized light microscopy (PLM), and transverse microradiography (TMR) were analyzed. Then the biocompatibility of DK5-Lips was evaluated in the caries model of Sprague-Dawley rats, and the anti-caries effect was assessed using Micro-CT analysis, Keyes scores and PLM in vivo. Results: : DK5-Lips provided a mean particle size of (97.63±4.94)nm and encapsulation efficiency of (61.46±1.44)%, exhibiting a sustained release profile, excellent stability in saliva, and no significant toxicity on human gingival fibroblasts (HGFs). DK5-Lips group had higher surface microhardness recovery, shallower caries depth and less mineral loss in bovine enamel. Animal experiments showed higher volume and density values of residual molar enamel, lower Keyes score, and shallower lesions depth of DK5-Lips group with good biocompatibility. Conclusion: As a safe and effective application model, DK5-Lips could significantly promote the remineralization of initial enamel caries both in vitro and in vivo. Clinical relevance: The potential of liposomes utilization as vehicle for oral delivery of functional peptides may provide a new way for enamel restoration.