Rsearch On Pereparation Multi-Channel Artificial Nerve Conduit Based On Electrospinning And 3D Printing

Peripheral nerve defects caused by accidents and iatrogenic injuries,if the patient does not receive timely treatment,may lead to lifelong disability.When the length of the nerve defect exceeds 5 mm,the end of the nerve cannot be sutured end-to-end,and a nerve graft is required to bridge the defect.Autologous nerve transplantation is recognized as the gold standard for the treatment of nerve injury,but it has the disadvantages of limited supply and disease on the donor site.Nerve conduits have great prospects in bridging peripheral nerve injuries by providing physical guidance and biological clues,and are increasingly regarded as potential alternatives for autologous nerve transplantation.In this study,a combination of electrospinning and 3D printing was proposed to prepare a multi-channel artificial nerve conduit,and reduced graphene oxide was introduced to prepare composite materials.The preparation process was studied and the structure and performance of the multi-channel nerve conduit were evaluated.Mainly include the following aspects:Through 3D printing single factor experiment and orthogonal experiment,the optimized preparation process parameters of the multi-channel nerve conduit microgroove were determined.The five main process parameters(printing temperature,nozzle height,nozzle inner diameter,scanning speed and feeding speed)that affect the3 D printing results were analyzed,and appropriate parameters were obtained for the next orthogonal experiment.A three-level orthogonal experiment with three factors(inner diameter of the print head,scanning speed and feed speed ratio)was designed,and the printing line width and height and average deviation were used as evaluation indicators.The range analysis results obtained the influence of process factors on the printing results.The size determines the optimal parameters for the preparation of the nerve conduit microgrooves by 3D printing.The polycaprolactone/reduced graphene oxide(PCL/RGO)nerve conduit basement membrane was prepared by electrospinning technology.By adjusting the content of RGO in the composite fiber film,the influence of different content of RGO on the structure and performance of the composite was analyzed.The results show that through the structure and performance characterization,the addition of RGO reduces the fiber diameter,improves the overall morphology of the fiber membrane,and improves the water absorption and hydrophilicity to a certain extent,which is beneficial to improve cell adhesion.It provides material ratio selection for the preparation of nerve conduit basement membrane.Using the optimized process parameters obtained by the 3D printing orthogonal experiment,3D printing micro grooves on the basement membrane of the nerve conduit successfully rolled the inner layer of the nerve conduit,and the 2mm thin shaft retractor was used for electrospinning to obtain the outer tube of the nerve conduit.Layers,inner and outer layers are assembled to finally prepare a multi-channel artificial nerve conduit.The performance of the nerve conduit was characterized by size test,mechanical test,in vitro degradation test and cytotoxicity test.It is proved that the multi-channel nerve conduit prepared by electrospinning and 3D printing technology has good pore size and porosity,and meets mechanical properties and controllable degradation in vitro.Cytotoxicity experiments show that both pure PCL and PCL/RGO nerve conduits show Good cell affinity.