Amelogenin Peptide-Chitosan Hydrogel for Biomimetic Enamel Regrowth

Abstract

We designed synthetic peptides that have demonstrated an effective remineralization potential to restore incipient enamel decay. In order to develop a clinically viable approach we incorporated the amelogenin-derived peptides P26 and P32 into chitosan hydrogel and examined their efficacy in the remineralization of enamel. Peptides in chitosan exhibited increased stability in vitro as compared to peptides in solution at room temperature and at 37°C. Tooth models for enamel erosion (sections) and white spot lesions (blocks) were subject to periods of demineralization. Treatment groups were subjected to remineralization in artificial saliva in the presence of P26 and P32 in solution and in chitosan hydrogel (P26-CS and P32-CS). Quantitative light-induced fluorescence (QLF) was employed to analyze mineral density following demineralization and remineralization across all the treatment groups. Scanning electron microscopy and nanoindentation were used to characterize the surface structure and mechanical strength of regrown enamel. Control enamel sections treated in artificial saliva demonstrated randomly distributed, tiny, needle-shaped crystals with a low packing density and porosities displaying mineralization defects. In samples treated with P26-CS or P32-CS a denser coating of organized hydroxyapatite (HAP) crystals was formed covering the entire surfaces of demineralized enamel window. The hardness and modulus of enamel surfaces were increased after treatment with P26-CS and P32-CS with no significant difference in the mechanical properties between the two peptide hydrogels. Analysis of mineral density by QLF showed that in enamel sections P26 peptide alone or P26-CS significantly enhanced the remineralization. In enamel blocks P26 in solution had a better efficacy than P26-CS.

Triple Function of Amelogenin Peptide-Chitosan Hydrogel for Dentin Repair

“…Peptide stability and production costs should be considered when facilitating the large-scale production and selection of peptides for clinical application. Combined with our previous findings on enamel remineralization, the peptide-CS hydrogel has the potential to treat tooth defects on multiple hard tissues, such as in noncarious cervical lesions (Mukherjee et al 2021).…”

“…We have used CS hydrogel to deliver amelogenin and its peptides for biomimetic enamel regrowth and remineralization. In addition to acting as an effective carrier, CS hydrogel has also shown antimicrobial effects and the ability to significantly improve peptides’ stability (Ruan et al 2013; Mukherjee et al 2021). The effectiveness of CS hydrogel in delivering amelogenin for enamel regrowth has also been demonstrated in an ex vivo pH cyclic system mimicking pH fluctuations in the oral cavity (Ruan et al 2016).…”

Synchrotron X-ray Studies of the Structural and Functional Hierarchies in Mineralised Human Dental Enamel: A State-of-the-Art Review

“…The combination of synthetic ACP nanoparticles and peptides was also investigated, a new layer was found on the enamel using SEM, and the texture determined with X-ray diffraction was found to be close to the control enamel [ 238 ]. Other studies reported the use of chitosan and the enamel matrix derivative protein amelogenin and peptides, which lead to the formation of new layers of material [ 239 , 240 ].…”

Synthetic extracellular matrices with function-encoding peptides

“…This peptide increases enamel mineralization and de novo crystalline hydroxyapatite depositions in vitro, and achieved mineralization of enamel in a clinical safety trial (UK National Research Ethics System; project number [10/H1207/75]) conducted in healthy adults with class V ‘white spot’ lesions 167 . Mimicking enamel glycoproteins, 26 and 32 amino acid amelogenin-inspired peptides (P26 and P32) can be engineered as hydrogels to promote the bottom-up formation of multilayered hydroxyapatite crystals on sectioned human molar teeth 168 . Similarly, enamel remineralization can be achieved with shorter amelogenin mimics, such as LEAWPATDKTKREEVD 169 and TKREEVD 170 , and with the tripeptide motif (DSS) derived from dentin phosphoprotein 171 .…”