Epithelial cell adhesion efficacy of a novel peptide identified by panning on a smooth titanium surface

Epithelial attachment via the basal lamina on the tooth surface provides an important structural defence mechanism against bacterial invasion in combating periodontal disease. However, when considering dental implants, strong epithelial attachment does not exist throughout the titanium-soft tissue interface, making soft tissues more susceptible to peri-implant disease. This study introduced a novel synthetic peptide(A10) to enhance epithelial attachment. A10 was identified from a bacterial peptide display library and synthesized. A10 and protease-activated receptor 4-activating peptide(PAR4-AP, positive control) were immobilized on commercially pure titanium. The peptide-treated titanium showed high epithelial cell migration ability during incubation in platelet-rich plasma. We confirmed the development of dense and expanded BL(stained by Ln5) with pericellular junctions(stained by ZO1) on the peptide-treated titanium surface. In an adhesion assay of epithelial cells on A10-treated titanium, PAR4-AP-treated titanium, bovine root and non-treated titanium, A10-treated titanium and PAR4-AP-treated titanium showed significantly stronger adhesion than non-treated titanium. PAR4-AP-treated titanium showed significantly higher inflammatory cytokine release than non-treated titanium. There was no significant difference in inflammatory cytokine release between A10-treated and non-treated titanium. These results indicated that A10 could induce the adhesion and migration of epithelial cells with low inflammatory cytokine release. This novel peptide has a potentially useful application that could improve clinical outcomes with titanium implants and abutments by reducing or preventing peri-implant disease.

Effects of grafting cell penetrate peptide and RGD on endocytosis and biological effects of Mg-CaPNPs-CKIP-1 siRNA carrier system in vitro

Calcium phosphate nanoparticles(CaPNPs)have good biocompatibility as gene carriers;however,CaPNPs typically exhibit a low transfection efficiency.Cell penetrate peptide(TAT)can increase the uptake of nanoparticles but is limited by its non-specificity.Grafting adhesion peptide adhesion peptide on carriers can enhance their targeting.The Plekho1 gene encodes casein kinase-2 interacting protein-1(CKIP-1),which can negatively regulate osteogenic differentiation.Based on the above,we produced a Mg-CaPNPs-RGD-TAT-CKIP-1 siRNA carrier system via hydrothermal synthesis,silanization and adsorption.The effects of this carrier system on cell endocytosis and biological effects were evaluated by cell culture in vitro.The results demonstrate that CaPNPs with 7%Mg(60 nm particle size,short rod shape and good dispersion)were suitable for use as gene carriers.The carrier system boosted the endocytosis of MG63 cells and was helpful for promoting the differentiation of osteoblasts,and the dual-ligand system possessed a synergistic effect.The findings of this study show the tremendous potential of the Mg-CaPNPs-RGD-TAT-CKIP-1 siRNA carrier system for efficient delivery into cells and osteogenesis inducement.