Preparation And Biological Properties Of Poly-peptide Modified Catechol-chitosan

Due to the unique anatomical structure of deciduous teeth and poor oral hygiene of children,high incidence of deciduous dental pulp disease and periapical diseases are caused.The most common treatment for deciduous pulpitis or periapical periodontitis is root canal therapy.Although root canal treatment can retain diseased teeth and extend their retention time,the teeth after root canal treatment become brittle,and the are easier to break or split than normal teeth,even prematurely loss.In recent years,with the development of cell biology and molecular biology,the treatment of deciduous dental pulp diseases and periapical diseases has slowly progressed toward the direction of biological therapy.Therefore,we envisage whether it is possible to prepare a material that serves as a carrier for dental pulp stem cells,promote the regeneration of pulp tissue,reconstruct the dental pulp system,and truly transform the treatment of endodontic and periapical diseases into biological therapyand provide new therapeutic approaches for the repair of dental pulp tissue.In this experiment,the research group chemically grafted catechol groups with strong tissue adhesive properties and biocompatibility into chitosan molecules,in addition,a poly-peptide(RADA16-RGD)capable of promoting migration,adhesion,and proliferation between cells is compounded therein.Cross-linking using natural cross-linking agent Genipin to prepare a new scaffolding material-poly-peptide modified catechol-Chitosan hydrogel,promotes stem cells from human exfoliated deciduous teeth adherence and proliferation on the surface,and provides dental pulp regeneration for deciduous teeth.We tracked the synthesis process of hydrogels by infrared spectroscopy,applied scanning electron microscopy images to analyze the structure of the materials,and applied mechanical strength,rheology,and moisture content to evaluate the physical and chemical properties of the materials.Results: We found that the catechol group was successfully grafted onto the chitosan molecule and showed uniform porous structure under the electron microscope,and it was superior to chitosan in other physical and chemical properties.After adding the poly-peptide,its functional group structure and physicochemical properties are similar to that of catechol chitosan,and no major physical and chemical properties change will occur due to the addition of the poly-peptide.In addition,in order to detect the biological properties of polypeptide modified catechol-Chitosan,we conducted molecular biology studies.First,dental pulp cells were extracted by enzyme-linked immunosorbent assay,then the osteogenesis and adipogenesis were identified.The cytotoxicity of the material was detected by MTT assay.The cells were co-cultured with the scaffold material,then the growth and extension of the cells on the surface of the material were observed by scanning electron microscope and HE staining.The cells were counted to evaluate whether the polypeptide modified catechol chitosan could promote cell proliferation on its surface.In the experiment,we successfully extracted the dental pulp cells and demonstrated that the extracted dental pulp cells had multi-differentiation ability through osteogenesis induction and adipogenesis induction.The MTT assay showed no cytotoxicity.Cell adhesion experiments showed that the poly-peptide modified catechol-Chitosan was superior to chitosan and catechol chitosan in terms of cell adhesion,proliferation,and extension.In summary,the experimentally-prepared poly-peptide modified catechol-Chitosan is a promising scaffold material.