Research On Preparation And Biological Properties Of Conductive Nanofibers

Nanotechnology has been developed rapidly,Electrospinning technology is a simple,fast and convenient method,which is widely used in the preparation of various nanomaterials.In the field of biomedical engineering,this technique is used to prepare various biomimetic materials for the treatment,repair or replacement of injured tissues or organs.The molecular structure of polyamide(PA)contains a lot of polar amide groups(-CO-NH-),which provides a friendly interface for cells and biological tissues with good cell compatibility.Preparation of PA nanofibers by electrospinning using PA solution of formic acid.The effects of main electrospinning parameters,such as voltage,collecting distance,humidity,temperature etc.,and solution parameters,for example,concentration etc.,on the microstructure and diameter of PA nanofibers were investigated.Carbon nanotubes are coaxial tubes of several layers,which is made up of hexagonal units composed of six carbon atoms connected to each other.It has a wide range of applications in the field of biomedicine,because of its unique physicochemical properties and good biocompatibility,mechanical properties and conductivity.Preparation of PA/CNTs composite nanofibers to explore the effect of CNTs on the properties of PA/CNTs composite nanofibers.Berberine hydrochloride is extracted from Coptis chinensis with broad antibacterial spectrum and can be metabolized or absorbed by human body,it has little side effect of normal tissue,so as a drug model for preparation of drug-loaded PA nanofibers and drug-loaded PA/CNTs composite nanofibers.The microstructures of nanofibers were observed by scanning electron microscopy(SEM).The mechanical properties of nanofibers were tested by universal testing machine.The conductivity of nanofibers under wetting was tested.The distribution of the drug contained was tested using an energy dispersive spectrometer(EDS).The drug release properties of the drug-loaded nanofibers were tested by in vitro drug release test.The bacteriostasis of drug-loaded nanofibers on Escherichia coli was tested by culturing E.coli on solid and liquid media.Mouse fibroblasts(L929)were inoculated on nanofiber membranes to test their biocompatibility.The results show that with the increase of PA concentration,the diameter of the nanofibers become thicker and the adhesion decreases.When the collection distance increases,the diameter of nanofibers decreases.The nanofibers diameter become thicker due to the increase of electrospinning voltage.When there is high air humidity,the nanofibers diameter become thinner,but there are small microspheres,the adhesion between the nanofibers is more serious.When the ambient temperature is relatively high(45?),nanofibers morphology is better,and relatively low(30?),there were composites were made of nanofibers and microspheres.When the PA solution of formic acid concentration is 12wt%,the voltage is 18 kV,the collection distance is 12 cm,the temperature is 45?,the humidity is 16%,the morphology of nanofibers are better.Compared with PA nanofibers,the morphology of PA/CNTs composite nanofibers does not change significantly,but the mechanical properties of PA/CNTs composite nanofibers are obviously enhanced.With the increase of CNTs content,the diameter of PA/CNTs composite nanofibers decreases and the conductivity increases.When the content of CNTs is 0.9wt%,the elastic modulus and ultimate strength of PA/CNTs composite nanofiber membranes are 802.59±15.24 MPa and 36.45±1.87 MPa,respectively,the conductivity is 2.9570×10-3±1.7570×10-5 S·mm-1.Both of drug-loaded PA nanofibers and drug-loaded PA/CNTs composite nanofibers have drug release properties,and the latter is better than the former.PA nanofiber membranes has no bacteriostatic on Escherichia coli.The bacteriostatsis of the drug loaded PA/CNTs composite nanofibers with different drug concentration in solid medium was more obvious with the increase of drug loading.Drug-loaded PA/CNTs composite nanofibers in liquid culture inhibited the growth of Escherichia coli,and with the increase of drug loading,the inhibitory effect was more obvious.MTT test results and SEM images of L929 cell adhesion and proliferation show that PA nanofibers,drug loaded PA nanofibers,drug loaded PA/CNTs composite nanofibers are not cytotoxic,and they conducive to the adhesion and proliferation of fibroblasts.The conductive composite nanofibers have potential application in repairing nerve tissue and guiding nerve tissue regeneration.