| Background and Objective:Periodontitis is an inflammatory disease,and severe periodontitis is the leading cause of tooth loosening and loss.Existing clinical treatment strategies can well control the progression of inflammation,but how to achieve destroyed periodontal tissue,especially functional periodontal regeneration,is still a clinical challenge.Clinically,guided tissue regeneration(GTR)is one of the most important technical means in the field of periodontal regenerative medicine.Typically,during GBR procedures,barrier membranes and osteoinductive materials are placed separately in the defect area,which increases the risk of infection and intraoperative bleeding.In order to solve this problem,the research group designed a Janus composite membrane with a hydrophobic and dense polylactic acid(PLA)on one side and a porous and hydrophilic hydroxyapatite on the other side.The Janus composite membrane of apatite achieves the dual function of blocking the growth of fibrous connective tissue such as gums into the wound area and inducing bone tissue regeneration.In this paper,we obtained Janus porous PLA barrier membrane(porous polylactic acid,PPLA)with one side dense and one side porous by evaporative phase separation,hoping to achieve dual functions through Janus structure.In order to further realize the function of promoting bone regeneration,we assembled the bioactive metal phenolic network(MPN)layer by layer on the surface of the porous structure,and finally formed a Janus porous barrier membrane(PPLA@MPN)with metal polyphenol bioactive interface.This topic mainly includes the following research contents:the assembly behavior of MPN in PPLA and its effect on the physicochemical properties of porous barrier membranes;the proliferation and migration of bone marrow mesenchymal stem cells(BMSC)by PPLA@MPN in vitro,The effect of osteogenic differentiation ability;the in vivo osteogenic effect of MPN was verified through a rat femoral defect model;PPLA@MPN promoted the proliferation,migration and formation of periodontal ligament stem cells(PDLSCs)by in vitro and in vivo experiments.The effect and mechanism of bone differentiation and regeneration of periodontal bone defect in the mandible of Wistar rats were discussed in depth.Materials and Methods:(1)Preparation and characterization of PPLA@MPN porous barrier membrane.The barrier membrane was observed and characterized by scanning electron microscope,energy dispersive spectroscopy,ultraviolet spectrophotometer and Fourier transform infrared spectrometer.The hydrophilicity,mechanical properties,enzymatic degradation rate,and swelling rate of the barrier membrane were also tested.(2)The sustained-release effect and osteogenic effect of PPLA@MPN on drug molecules were verified.A barrier membrane model of PPLA@MPN loaded with rhodamine B and bone morphogenetic protein(BMP-2)was constructed to study the effect of MPN on the sustained release of drug molecules.The growth state of cells on the barrier membrane was observed by scanning electron microscopy and staining of dead and living cells,and the induction of MPN on cell migration and stem cell differentiation was verified in vitro by migration assay and alizarin red staining.Then,the PPLA@MPN barrier membrane was loaded and implanted into a rat femoral defect model to further study the effect of the barrier membrane on osteogenesis in vivo.(3)To verify the regeneration-inducing effect of PPLA@MPN membrane on periodontal bone tissue.The cytotoxicity of the material was characterized by dead and live cell staining and CCK8,and the growth state of cells on the barrier membrane was observed by confocal microscopy and scanning electron microscopy.The immunoregulatory effects of PPLA@MPN membranes were verified by flow cytometry,real-time quantitative PCR,and immunofluorescence staining.The angiogenesis and osteogenic effects of PPLA@MPN membranes were verified by migration experiments,tubule formation experiments,alizarin red staining experiments,and fluorescence quantitative PCR,respectively.Finally,the barrier membrane was implanted into the mandibular periodontal bone defect model of Wistar rats,and the healing of the bone defect was analyzed and compared by Micro CT scanning.Results:(1)The Janus porous barrier membrane-PPLA@MPN with MPN bioactive interface was obtained,and the surface assembly of MPN and its effect on the physicochemical properties of the porous barrier membrane were elucidated.(2)The MPN bioactive interface in the PPLA@MPN porous barrier membrane can realize the controlled and sustained release of drug molecules,promote stem cell homing and osteogenic differentiation behavior.(3)The PPLA@MPN porous barrier membrane can achieve enhanced periodontal bone regeneration through the multiple effects of immune-angiogenesis-osteogenesis.Conclusions:In conclusion,we constructed a PPLA@MPN barrier membrane.The dense PLA surface in the Janus structure can realize the function of the barrier,and the MPN bioactive coating in the porous structure can be realized by means of sustained drug release,cell behavior regulation,and immune microenvironment regulation.The multiple effects of immune-angiogenesisosteogenesis are finally effectively promoted in bone repair in periodontal defects.This study provides an effective periodontal bone tissue regeneration strategy for clinical work,and also provides a tissue-engineered branch barrier membrane material for bone tissue regeneration to promote repair. |
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