Preparation Of Gold Nanoparticles Modified Composite Polycaprolactone Nanofiber Membrane And Research On Its Osteogenic Properties

BackgroundOral and maxillofacial inflammation,tumor,congenital deformity,trauma and so on often cause different degrees of oral bone tissue defects,usually need to use a variety of bone tissue engineering scaffold materials to complete the repair work.The central link of tissue engineering technology is the design of scaffold materials,and the nanofiber membrane constructed by electrospinning is not only similar to the extracellular matrix in structure,but also has good physical and chemical properties,and has a wide range of applications in the fields of drug release,wound excipients and tissue engineering scaffolds.In addition,polymer materials commonly used in electrospinning have problems such as poor hydrophilicity and low mechanical strength,and the lack of functional groups limits their application in bone tissue engineering.The development and application of gold nanoparticles(AuNPs)has always been a hot topic in the field of medical biology.In recent years,the research of AuNPs in the field of bone tissue regeneration has also made a great breakthrough.A novel composite tissue engineering scaffold was constructed by combining AuNPs as functional groups and electrospun fibers.It is expected to provide a new scaffold material for the repair of oral and maxillofacial bone defects.ObjectiveThe purpose of this study is to construct a functional tissue engineering scaffold by electrospinning technology with high mechanical properties with good biocompatibility and osteogenic function,and to study its physicochemical properties,cytocompatibility and in vitro osteogenesis effect.Material and MethodsPolycaprolactone(PCL)nanofiber membrane was prepared by electrospinning technology.Dopamine(PDA)was uniformly attached to the surface of the PCL nanofiber.The 45nm AuNPs were prepared by chemical reduction method.The AuNPs were adsorbed on the PCL/PDA nanofiber membrane by PDA coating to form a composite nanofiber film as a scaffold for bone tissue engineering.The composite nanofiber membrane was characterized by SEM,TEM,XPS,mechanical test,hydrophilic test and other methods.The composite nanofiber membrane was co-cultured with rat bone marrow mesenchymal stem cells(RBMSCs),and the cell activity was detected by CCK-8.The osteogenesis differentiation of BMSCs were detected by ALP activity,ALP staining and RT-q PCR.ResultsThe results show that:(1)The gold nanoparticles prepared by chemical reduction method were spherical and had good dispersion with an average particle size of about 45nm under the electron microscope.(2)Scanning electron microscopy showed that the PCLnanofiber membrane was a uniform nanofibrous structure,and interwoven in a network.After the treatment of PDA,the surface of the membrane became rough.(3)High power scanning electron microscope observation showed that a large number of gold nanoparticles were attached to the surface of PCL/PDA composite films after AuNPs treatment,while the surface of PCL nanofibers without polydopamine modification almost did not contain gold nanoparticles.The results of XPS and micro-CT further confirmed that gold nanoparticles were successfully adsorbed on the surface of PCL/PDA composite nanofibers.(4)Mechanical properties:the tensile fracture mechanical properties of the three different nanofiber membranes could be seen that PCL/PDA@AuNPs composite nanofiber membrane has higher elastic modulus and tensile strength with the maximum elongation at break.(5)The detection of hydrophilic contact angle shows that compared to the PCL fiber membrane and PCL/PDA composite fiber membrane,the PCL/PDA@AuNPs composite nanofiber membrane has better hydrophilicity.Rat bone marrow mesenchymal stem cells(r BMSCs)were co-cultured with composite nanofibrous membranes containing different amounts of AuNPs.The growth of cells on different fibrous membranes was observed by scanning electron microscopy and fluorescence staining.The number and adhesion of cells on the composite membrane containing AuNPs were better.CCK-8 test?ALP active staining and ALP quantification showed that PCL/PDA@AuNPs(2)had better cytocompatibility and ability to induce osteogenic differentiation of r BMSCs.RT-q PCR assay was performed to detect the expression of osteogenic related genes by using PCL/PDA@AuNPs(2).The results showed that PCL/PDA@AuNPs(2)could promote the early expression of ALP,Runx2,Col-I and OPN of r BMSCs osteoblasts,and had a good effect on osteoblast differentiation.ConclusionAfter surface treatment of PDA,PCL nanofiber membrane obtained by electrospinning not only enhanced the physical and chemical properties of the fiber membrane,but also made gold nanoparticles firmly attached to the fiber membrane,which further improved the mechanical strength of the nanofiber membrane and enhanced its hydrophilicity,thus forming scaffold materials with good biocompatibility:PCL/PDA@AuNPs composite nanofiber membrane.The cell viability and osteogenic properties of r BMSCs co-cultured with AuNPs(60g?g/cm~2)showed that the composite nanofibrous membrane was cytocompatible.The composite nanofibrous membrane with appropriate AuNPs(60?g/cm~2)could induce osteogenic differentiation of RBMSCs and promote the expression of osteogenic related genes,showing a good potential to promote bone tissue regeneration,which was expected to be a new bone tissue repair material.