Fabrication And Biocompatibility Of Electrospun Conductive Silk Nanofiber

With the rising and development of nano technology,nano materials applie in more and more broad.Electrospinning technology is an effective method for preparing nanofiber,nano fibers and nano yars can be obtained which diameters rang from few nanometers to tens of microns by this way.In recent years,electrospun silk nanofiber applied for filter material,Engineering scaffold material,wound dressing material,gauze and other aspects of the application.But mechanical properties of silk fibroin nanofibers have some limit for applications.In this paper,blending and surface coating method was used to change the disadvantage and conductive silk nanofibers was fabricated successfully.It is hoped that the conductive material can use for he repair of peripheral nerve and provide some theoretical basis.Preparation of silk fibroin solution with formic acid/salt dissolving process,the mass fraction of carbon nanotube in the solution was 0,0.5%,1%,1.5%and 2%.Field emission scanning electron microscope and transmission electron microscope used to observe carbon nanotubes in the tunnel of silk nanofiber and found carbon nanotubes can be evenly distributed along the fiber radial in silk nanofibers.Adding little amount of carbon nanotubes can improve the mechanical properties of nano fiber felt,the strength of break was up to 9.94±1.2MPa and fiber flexibility decreased at the same time.The conductivity of fiber was also improved dramatically.The results showed that the addition of carbon nanotubes had no significant effect on the structure and molecular conformation of silk fibroin.Using FeCl₃ as oxidant and dopant,by in situ oxidation polymerization,conductive silk nanofiber mats was successfully prepared polypyrrole/silk fibroin composite nanofibers,the highest conductivity of 1.4±0.2S/cm.Reaction time and concentration of oxidant have important effect on the conductivity of composite materials.Results shown that the reaction temperature is 5?,FeCl₃ solution is 0.8mol/L,reacted 5h can reach the best conductive effect.Through the comprehensive analysis and comparison of two kinds of conductive composite nanofibers,the polypyrrole/silk fibroin nanofiber mats for cell culture of neural stem cells,the results showed that the energy in this type of material attached to the growth,and using different current and conduction time to stimulate neural stem cells,analysis and comparison of electrical stimulation on nerve growth morphology stem cells,value-added effect.The result shown that electrical stimulation has effect on the growth of cell,and low electric and short time stimulation can obtain better result.100?A current,15min/d,continuous 3days and 7days later the test result shows that the activity and growing form of the cell are best.By adding multiwalled carbon nanotubes to spinning solution and coating polypyrrole on the surface of nanofiber,carbon nanotube/silk fibroin composite nanofibers and polypyrrole/silk fibroin nanofiber composites were prepared successfully,the analysis results show that the addition of carbon nanotubes not only on the mechanical properties of silk fibroin nanofibers improved,but also conducive to the improvement of conductivity;the surface of polypyrrole coated conductive properties of silk fibroin nanofibers has significantly increased,the maximum conductivity can reach 1.4±0.2S/cm,and the conductive wire Sunami fiber has good biocompatibility of neural stem cells,neural stem cells can attach to the surface of the material.