Manufacture And Application In Tissue Engineering Of Silk Fibroin Nanofiber Produced By Air/jet Electrospinning

Along with the development of nano-technology, the manufacture method of one dimension nano material--electrospinning was highlighted in recent years. Compared with the traditional structure of biological materials, the material produced byelectrospinning has some extra merites as listed behind. â‘ Special three dimensional porous structure with the pores fully interpenetrated, â‘¡very large surface area to volume ratio which is fit for the cell adhesion and the anchor of functional protein, â‘¢the ability of producing material with multilayer and multiphaseor hollow fibers which has the advantage for producing organic and inorganic composite and functional gradient material or drugcontrolled release system, â‘£ having the accordance with thesupport tissue in micro-structure, so it provide a method for simulating the extra cellular matrix. So in recent years, theelectrospinning nanofibers has been using as tissue engineering scaffold material. The unique air/jet electrospinning device has provide a brand new method for producing nano-fibers.In this case, we have chosen the silk as the object for it has abundant supply and is excellent in mechanical and biological property. The purpose of this study is to determine the property of the silk for being electrospun and look for the difference between traditional electrospinning and air/jet electrospinning. With the effect of different electric voltage, solution concentration, distance between two electric pole, air flow rate, look for the difference of the two techniques, to find out the applicable management of air/jet electrospinning and polish up the device.In this study, silk fibroin nano-fibers could be made by the two methods, and the average diameter could be limited under lOOnm degree. And the nonwovens of silk fibroin nanofibers could be made also. In electrospinning, it could be observed that the diameter of the silk fibroin could be raised by increasing the concentration of the solution or the distance between the electric pole, when elevate the electric voltage the fiber diameter could be decreased. In air/jet electrospinning, the diameter of the fiber could also be decreased by increasing the air flow rate. But in the latter situation, the diameter of the fiber has no difference when the distance of the electric pole increased from 10cm to 20 cm which is different with the situation of the electrospinning, it meansthat the stretching distance of the fibers could be extended in which the molecular chain could be made paralleled to each other and the mechanical and geometric property could be improved with this method. It is found that few beads and less fiber conglutination were observed in the air/jet electrospinning specimen, but not in the specimen under 10cm situation. There is still a hard work for make the electric voltage and air flow work together properly. In addition, it is found when add some PVA into the solution the volume of the silk fibroin could be cut down without destroying the size property of the fiber. So it could be done by blending the polymer into the protein solution for improving the mechanical property of the fiber.Most of the cells in the human body are adherent cell, and the cells could spread and proliferate unless the cells were adhered. In vivo or in vitro, the first thing that cells touched is the surface of the material. So it is very important for estimating the tissue engineering scaffold, to detect the cell adherence and proliferation on the material surface. In this study, the laser confocal scanning microscope, scanning electro microscope and the MTT were used to detect the adherence and proliferation of the human gingival fibroblast(HGF), rat' s marrow stromal cell(BMSC), human umbilical vein endothelial cell strain (ECV-304), and KB cell strain on the surface of the silk fibroin nano-fiber nonwovens.Except the KB cell strain, all other cells demonstrate good affinity with the nonwovens. In the 4h situation, cells establishedfirm adherence on the surface of the nonwovens, and 35. 78%-75.9% cells had being spreading. The HGF, BMSC, ECV-304 could proliferate on the nonwovens and have better proliferation rate than the control.From the work, it was found that the silk fibroin could be made into nano fibers through air-jet electrospinning, and the cells could adhere, spread; and proliferate on the surface of the nano-fiber nonwovens. The silk fibroin nanofibers has got the advantage to be good tissue engineering scaffold.