Device Development And Mechanism Study On High-throughput Preparation Of Regenerated Silk Fibroin Nanofibers

Natural silk has been used as a textile fiber in clothing for thousands of years.Silk threads have also been used as surgical sutures for a long time.Silk fibroin(SF),as a natural polymer protein molecule in natural silk,also shows great application potential in the biological field.Recent studies have found that the regenerated silk fibroin(RSF),as a non-toxic and non-side effect biological material,exhibits good air permeability,moisture permeability and hydrophilicity,and its application forms are also various,such as fibers,membranes,nanospheres,etc.Nowadays,RSF has been highly valued by researchers at home and abroad in the application of biomedical materials.On the basis of our previous researches,the self-made modified bubble electrospinning(MBE)device was used to prepare RSF/sodium dodecylbenzene sulfonate(RSF/SDBS)nanofibers in batches at frist;then based on the MBE device,an modified free-surface electrospinning(MFSE1)device was developed and used to prepare RSF/hydroxypropylmethyl cellulose(RSF/HPMC)nanofibers in batches.Both of the two obtained nanofibers were characterized and their cell compatibility was compared.Finally,in order to further improve the production efficiency of nanofibers,three types of free-surface electrospinning(FSE)devices were developed,which are the modified FSE(MFSE)device,the oblique section FSE(OSFSE)device and the spherical section FSE(SSFSE)device,respectively.Maxwell 3D was used to numerically simulate the electric field distribution produced in the above four FSE processes,respectively,and their spinning mechanisms were compared and studied.At the same time,the spinning effects of polyacrylonitrile(PAN)nanofibers prepared in batches by these four FSE devices were experimentally studied,and the numerical simulation results were verified by the experimental data.The details are as follows:(1)RSF/SDBS nanofibers were prepared in batches by MBE.The effects of SDBS and RSF concentrations on the properties of the spinning solution and the morphology,properties and yield of the nanofibers were studied.And the influences of air flow on the quality and yield of products also were analyzed.The results showed that the addition of SDBS improved the spinnability of the RSF solution,while the decrease of gas flow volume enhanced the quality and yield of nanofibers.When the SF concentration was 10 wt%,the SDBS concentration was 0.1 wt%,and the gas flow volume was 50m3/h,the maximum yield could reach 3.10 g/h.(2)Based on the MBE device,MFSE1 was developed and used for high-throughput preparation of RSF/HPMC nanofibers.The effects of the mass ratio of RSF to HPMC and the spinning voltage on the morphology,properties and yield of nanofibers were studied.The results showed that with the increase of HPMC contents,the mechanical properties and hydrophilicity of RSF/HPMC nanofiber membranes would be improved,but the yields of them would decrease.And with the increase of spinning voltage,the yields of nanofibers increased.When the mass ratio of RSF to HPMC was 7:1 and the spinning voltage was 61kV,the quality and yield of the nanofibers obtained were relatively best.In addition,based on the cell micrographs and cell viability tests of human umbilical vein endothelial cells,it was found that the RSF/HPMC nanofiber membrane with the mass ratio of 7:1 had good cell compatibility.(3)Maxwell 3D was used to simulate numerically the electric field distribution produced in the spinning processes of the MBE,MFSE,OSFSE and SSFSE devices,respectively,and their spinning mechanisms were compared and studied.At the same time,the spinning effects of the high-throughput production of polyacrylonitrile(PAN)nanofibers using these four FSE devices were experimentally investigated,and the experimental data verified the numerical simulation results.The results showed that the electric field distribution produced in the FSE process had an important influence on the spinning effects.And all of these four FSE devices could be used to produce nanofibers with a high yield.Among them,SSFSE had the best spinning effect,and the quality and yield of PAN nanofibers fabricated were highest.