Remineralization of enamel caries by an amelogenin-derived peptide and fluoride in vitro

Dental caries is one of the most common oral diseases in the world.This study was tantamount to investigate the combinatory effects of an amelogenin-derived peptide(called QP5)and fluoride on the remineralization of artificial enamel caries.The peptide QP5 was synthesized and characterized,and the binding capability of the peptide on hydroxyapatite(HA)and demineralized tooth enamel surface was analysed.Then,the mineralization function of the peptide and fluoride was studied through the spontaneous mineralization testing and remineralization on enamel caries in vitro.First,the novel peptide QP5 could bind on the hydroxyapatite and demineralized tooth enamel surfaces.Second,QP5 can transitorily stabilize the formation of amorphous calcium phosphate and direct the transformation into hydroxyapatite crystals alone and in combination with fluoride.In addition,compared to blocks treated by peptide QP5 alone or fluoride,the sample blocks showed significantly higher surface microhardness,lower mineral loss and shallower lesion depth after treatment with a combination of QP5 and fluoride at high or low concentrations.The peptide QP5 could control the crystallization of hydroxyapatite,and combinatory application of peptide QP5 and fluoride had a potential synergistic effect on the remineralization of enamel caries.

Promoting effect of a calcium-responsive self-assemblyβ-sheet peptide on collagen intrafibrillar mineralization

Recently,a de novo synthetic calcium-responsive self-assemblyβ-sheet peptide ID8(Ile-Asp-Ile-Asp-Ile-Asp-Ile-Asp)has been developed to serve as the template inducing hydroxyapatite nucleation.The aim of this study was to evaluate the effect of ID8 on intrafibrillar mineralization of collagen making full use of its self-assembly ability.The mineralization experiments were carried out in vitro on both bare TypeⅠcollagen and fully demineralized dentin samples.The calcium-responsive self-assembly of ID8 was revealed by circular dichroism spectrum,8-anilino-1-naphthalenesulfonic acid ammonium salt hydrate assay,attenuated total reflection Fourier transform infrared spectrum(ATR-FTIR)and transmission electron microscope(TEM).Polyacrylic acid(450 kDa)with a concentration of 100μg ml^(-1)was selected as the nucleation inhibitor based on the determination of turbidimetry and TEM with selected area electron diffraction(TEM-SAED).The results showed that collagen intrafibrillar mineralization was significantly promoted with the pretreatment of self-assembly ID8 detected by TEM-SAED,SEM,X-ray diffraction and ATRFTIR.The pretreatment of collagen utilizing self-assembly ID8 not only enhanced intermolecular hydrogen bonding but also contributed to calcium retention inside collagen and significantly increased the hydrophilicity of collagen.These results indicated that peptides with self-assembly properties like ID8 are expected to be potential tools for biomimetic mineralization of collagen.

Evaluating the potential of an amelogenin-derived peptide in tertiary dentin formation

Several novel biomaterials have been developed for dental pulp capping by inducing tertiary dentin formation.The aim of this study was to evaluate the effect of QP5,an amelogenin-based peptide,on the mineralization of dental pulp cells(DPCs)in vitro and in vivo.The cell viability of human DPCs(hDPCs)after treatment with QP5 was determined using the Cell Counting Kit-8(CCK-8).Migration of hDPCs was assessed using scratch assays,and the pro-mineralization effect was determined using alkaline phosphatase(ALP)staining,alizarin red staining and the expression of mineralization-related genes and proteins.The results showed that QP5 had little effect on the cell viability,and significantly enhanced the migration capability of hDPCs.QP5 promoted the formation of mineralized nodules,and upregulated the activity of ALP,the expression of mRNA and proteins of mineralization-related genes.A pulp capping model in rats was generated to investigate the biological effect of QP5.The results of micro-computed tomography and haematoxylin and eosin staining indicated that the formation of tertiary dentin in QP5-capping groups was more prominent than that in the negative control group.These results indicated the potential of QP5 as a pulp therapy agent.