Electrospinning Preparation Of Nanoyarn Build New Nerve Conduits

Peripheral nerve injury is a common clinical damage, which widely exists in thecar accident, occupational injury and daily life. Autologous nerve grafting remains thegold standard for the majority of peripheral nerve repairs. However, autologous nervegrafting is limited due to unavailability of donor nerves and donor sit morbidity.Autologous transplants have been unable to meet the requirements. Nerve conduits haveemerged as alternatives to autologous nerve grafts. Nerve conduits can provide a suitablemicroenvironment for nerve repair, which can guide cell migration and axon growth.The hollow structure of nerve conduits is not beneficial for cell adhesion, cellgrowth and providing guidance for nerve growth, so it is not in favor of nerve growing tothe far ends. It also affects the speed and effect of nerve repair. In order to solve theproblems, we designed to use the nanoyarn as the core layer of nerve conduits. In thispaper, the nerve conduits were prepared by improved electrospinning apparatus andnanoyarn was obtained by optimizing the electrospinning parameters and collectingapparatus. The device was composed of double electrospinning system, high speedrotating metal funnel and yarn winding device as a collector. The needles were placed onboth sides of the pump and provided the same velocity, with positive and negativevoltage respectively. During the process of electrospinning, by adjusting the angle of thenozzle, nanofibers gathered in high speed rotating funnel mouth. After that nanoyarn wasmoved out by metal rod and made its end winding to the yarn winding device. Nanoyarnwas collected by the winding device rotating. Due to metal funnel and winding devicerotated in different directions, the thousands of nanofibers twisting formation nanoyarn.The nanoyarn had good mechanical properties and biocompatibility. Scanning electronmicroscope (SEM) revealed that the nanoyarn was composed of aligned nanofibers.Mechanical test demonstrated that high orientation degree of nanoyarn had excellent mechanical properities. Schwann cells (SCs) were utilized as cell sources to examin thebiocompatibility of nanoyarn scaffolds. MTT assay showed that nanoyarn with highorientation degree was in favor of the proliferation of the cells and was better thanrandom nanofibers. SEM and laser confocal scanning (CLSM) images confirmed thatSCs spread out well along the axial direction on the nanoyarn, and high orientationdegree of the nanoyarn can induce SCs directional migration.Nanoyarns parallel arrangement in the surface of the metal bar, and fixed at bothends. Metal bar rotating receiving the nanofibers and formed a layer of P (LLA-CL)nanofiber membrane on the outside of nanoyarn. The nerve conduits were filled withnanoyarn. MTT results showed that the nerve conduits were composed of nanoyarnwhich cells grow better than the hollow structure nerve conduits. SEM and CLSMimaged confirmed that Schwann Cells spread out well on the core layer containingnanoyarn nerve conduits, SCs growth along the nanoyarn axes. So the nerve conduitscomposed of nanoyarn were more advantageous to cells proliferation and directionalmigration.