A Peptide-Based Biomineralization Strategy for Tooth Repair

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PROJECT SUMMARY / ABSTRACT We seek to develop a biomineralization approach to grow a biomimetic enamel-like layer that will have a seamless chemical attachment to natural enamel and dentin. Such a structured biomaterial will prevent progression of tooth decay and will be utilized as an enhanced dental restorative material for treating non- carious cervical lesions (NCCL). We reported that our patent-pending hydrogels composed of chitosan and amelogenin (CS-AMEL) can promote regrowth of an enamel-like layer and remineralize dentin. Here, we will utilize an amelogenin-inspired peptide-based biomimetic strategy. The advantage of using peptides for translational/clinical purposes lies in the fact that short peptides are easier to use as well as more economical and practical for clinical application. The pathway to regulatory approval may also be easier for peptides. We hypothesize that our rationally designed peptide chitosan hydrogel (Amel-P-CS) will stimulate growth of an enamel-like mineralized layer at the dentin/enamel interface and will promote guided remineralization of the dentin collagen compartments, thereby enhancing bonding to the organic content in dentin. Following specific aims are proposed: Aim I) To investigate the assembly and apatite mineral-forming potential of amelogenin- derived peptides P26 and P32 prior to their application in the chitosan hydrogel. We will use CD, Cryo-TEM, micro Raman spectroscopy and in situ AFM to investigate the peptides’ secondary and tertiary structures and their influence on apatite mineralization in the presence and absence of collagen in vitro. Aim II) To develop and optimize the formulation of P26 and P32 peptide-containing chitosan hydrogels (Amel-P-CS) and examine the potential of Amel-P-CS hydrogels to rebuild an enamel-like layer with enhanced mechanical properties and robust attachment to etched enamel surface. Human molar crown slices with demineralized enamel surfaces will be used. Aim III) To examine the potential of Amel-P-CS hydrogels to rebuild an enamel-like layer with enhanced mechanical properties and robust attachment to a demineralized dentin surface. We will further examine the potential of the hydrogels to nucleate and grow apatitic crystals within the dentin collagen compartments, thereby enhancing bonding to the organic content in dentin. Human molar crown slices with demineralized dentin surfaces will be used. Aim IV) To examine the efficacy of Amel-P-CS hydrogels in repairing artificial cervical lesions in ex vivo models where enamel and dentin are exposed. We will use whole extracted teeth subjected to a pH-cycling regimen. In summary: If the goals of proposed aims are achieved, we will deliver a technology (hydrogel delivered on dental trays) that: a) will provide enhanced biomimetic enamel-like coating material, b) effectively rebuild dental structures lost due to NCCL lesions, and c) will prevent dentinal hypersensitivity and progression of tooth decay.