Preparation Of SF/PLGA Nanofiber Scaffolds By Multi-mode Electrospinning And Its Application

Electrospinning is one of the effective methods to produce nanofibers.The preparation of nanofibers by this technology has many advantages,such as high porosity and small diameter.Therefore,this technology is widely used in various fields such as tissue engineering scaffolds and material filtration.Scaffolds prepared by electrospinning technology have the following characteristics:1)Scaffolds can simulate the native extracellular matrix(ECM)topology structure,high porosity and specific surface area which can support cells adhesion and differentiation;2)By adjusting the properties of the electrospinning solution and spinning process parameters,nanofibers with different morphologies and diameters can be obtained,which can meet the requirements of different tissues;3)By choosing natural or synthetic materials,or the two mixed materials,scaffolds with good mechanical properties and biological properties can be obtained to meet different needs.Therefore,using this technology to prepare different types of tissue engineering scaffolds has become a research hotspot.A multifunctional electrospinning experimental system is designed,which effectively reduces the cost of experimental equipment.The receiver designed multimode of single drum electrode,static parallel double drum electrode and dynamic parallel double drum electrode to complete the multiple tasks of electrospinning process research and preparation application.The injection pump adopts stepping motor as the actuator to achieve a straight line reciprocating movement.The PLC is used as the controller.It adjusts the syringe pump,high-voltage power supply and receiver through the manmachine interface,so as to control the electrospinning experiment.The fuzzy control PID controller is designed for the spinning solution flow rate system to further improve the stability of the flow rate.In order to control the flow rate of spinning solution more accurately,the model of the flow rate control system is analyzed first,and the fuzzy control does not need to establish a very accurate mathematical model of the controlled object,which can make the deviation as close to zero as possible and better realize the regulation of fiber properties.The box Behnken design(BBD)method of Response Surface Methodology is selected to optimize the electrospinning process,and the diameter prediction model is studied.The relationship between the diameter of nanofibers prepared by electrospinning technology and its influencing factors can not be accurately digitized.The binary regression model of fiber diameter and experimental conditions is established,the influence degree of various factors on fiber diameter through the analysis of the obtained model is obtained.Moreover,the change trend of fiber diameter with experimental conditions can be seen more intuitively through the three-dimensional diagram of response surface analysis.In the electrospinning process,there are many influencing factors,such as solution concentration,spinning voltage,solution flow rate and receiving distance.The BBD design method of three factors(solution concentration,electrospinning voltage and solution flow rate)and three levels is adopted in the surface response design.The effects of experimental electrospinning parameters on lactic acidglycolic acid copolymer(PLGA)and silk fibroin(SF)fiber diameter are systematically studied,and the binary regression model is established.The comparison between the predicted value and the actual value provides a basis for obtaining the best electrospinning parameters in the later test of this study.The Sandwich layered electrospun SF and PLGA is selected to construct fiber scaffolds.SF is a natural polymer material with good biocompatibility.Its low cytotoxicity,inflammatory reaction and relatively low manufacturing cost make it widely used in the field of biomedicine.PLGA has good biocompatibility and processability.It is one of the preferred materials for preparing tissue engineering scaffolds.The brittleness of SF is overcome,the mechanical properties of SF and the hydrophilicity and biocompatibility of PLGA are both improved by composing spinning of SF and PLGA.Not only the shortcomings of single material,but also the shortcomings of material property denaturation caused by mixing and dissolving are overcome by the scheme of layered electrospinning.The nano-fiber scaffold is designed as sandwich type,PLGA is placed in the middle,SF is placed on both sides,which not only solves the fragile performance of SF itself,but also does not affect the biological performance of SF in cell culture.Therefore,the sandwich type composite nano-fiber scaffold can be applied to skin tissue engineering.The performance properties and biological evaluation of SF/PLGA fiber scaffolds obtained by electrospinning are carried out.The selected electrospinning materials are used electrospinning technology to construct a composite nanofiber scaffold with the average diameter of nanofibers as the target value.The growth morphology of cells on nanofibers was observed by laser confocal microscope and scanning electron microscope.The proliferation of cells on electrospun nanofiber membrane is observed by CCK-8 method.The experimental results show that SF/PLGA composite nanofiber membrane can provide a good growth environment for cells without cytotoxicity,and has a good application prospect in the field of tissue engineering.