Electrostatic Spinning Method Prepared PCL_PLA Nanofibers And Its Research In Biological Materials

Electrospinning is a technology that be capable of producing continuous nano fibers under high voltage field nowadays. By slenderizing the polymer to form one-dimensional nano-fiber with high porosity and larger specific surface area which can be widely used in tissue engineering bracket or imitate cell extracellular matrix including functional scaffolds for cell growth. As for the substrate materials, well biocompatibility and biodegradability characteristics of the material are demanded.In this paper, polycaprolactone and polylactic acid were selected as a scaffold material, utilizing electrospinning to prepare composite nanofiber scaffolds. Firstly, the spinning process conditions were optimized to prepare suitable biological material pertinence nanofibers. Then, by means of diverse testing, various properties of the stent material were studied such as scanning electron microscopy (SEM), mechanical properties, infrared spectroscopy, fluorescence spectrum, burst strength. With those indexes the fiber morphology, the stress and strain of the stent, the ratio of materials, biological adaptability and vascular material can withstand burst pressure performance were characterized.The results showed that under the electrospinning parameters of8%-10%wt solution concentration, voltage of28KV to30KV, the receive distance of10cm to15cm, nano-fiber with relatively preferable morphology and diameter distribution was obtained. If the concentration of the solution is increased from6%to8%with other experiment parameter remain unchanged, the occurrence of beads was reduced while the fiber diameter increases into good uniformity. However, the fiber diameter became thicker accompanied by breakage, eventually failure to form continuous nanofibers when the concentration of the solution is increased from8%to12%. When the voltage rises from24KV to28KV, the fiber diameter is decreased, and beaded significantly disappears. On the contrary, a fiber diameter became obviously thicker and a rough surface of the fiber membrane was formed at the38KV voltage. In the optimizing process of received distance, the fibers were flattened at5cm. Yet the receive amount of fibers is suffering from a significant loss at20cm.The PCL/PLA nanofibers were collected on a rotation drum. A higher radial orientation fiber membrance was obtained under the rotational speed of1000r/min than those obtained under500and1500r/min, from the profiles of the scanning electron microscopy (SEM). The infrared spectroscopy of the PCL/PLA blend fiber membrane did not any new peaks, and that showed no group mutation in the spinning process of the two materials. Referring comprehensive test results of SEM, mechanical properties and burst strength, a good overall performance nano-fiber membrane was acquired at PCL/PLA ratio of1:1, voltage of28kV and10cm receive distance. In addition, a fluorescent protein is introduced into the electrostatic spinning scaffold material, and cultured with medium to study the diffusion speed of the fluorescent protein in a certain period of time, fluorescence spectra was characterized. The saturation concentration is about20.5mg/ml.This thesis show that a certain ratio of nano fibers by electrospinning preparation of PCL/PLA stent material has a certain mechanical properties and biological properties. Among the tissue engineering scaffold material preparation technology,electrospinning nano-fibers has excellent porous three-dimensional porous scaffold structure exists in a certain space on the structure, it is possible to meet needs such as tissue engineering.