| During the surgery of bypass and replacement in vascular, because of thrombosis in small-diameter artificial vascular, which lead to implant failure early. In order to solve the problems of small blood vessels, people do a lot of work in the choice of the polymer materials and the improvement of processing technology, but the effect is not very obvious, therefore, the related research and exploration about the improvement of these problems were done in this paper further.This subject combines with nanotechnology, electrostatic spinning technology, and biomedical material (degradation of materials and biodegradable materials). Small diameter artificial vascular were prepared with independent intellectual property rights, good biocompatibility and being closer to a host of blood vessel to overcome the restenosis in the blood vessels caused by the transplantation.This paper refers to the choice of materials of artificial small blood vessel, and the improvement of electrostatic spinning device in two aspects, on the one hand, changing the collection into corrugated and tapered, on the other hand spinning with double injection pumps in the opposite directions and then choose reasonable tapered and corrugated parameters to produce artificial vascular graft,finally to do Biomechanical testing and culture cell on artificial small blood vessel samples, analysing its biocompatibility and various performance indicators of blood vessels.Using double injection pumps in the opposite directions to spin nanofibers, Produce vascular graft 5mm in diameter with mixed PET and PLLA,drug-loading on which,solvent are chosen with chloroform acetone (volume ratio 2:1), trifluoro ethyl and methylene chloride (volume ratio 4:1) mixed solvents. Through the test analysis of PET/PLLA get the optimal parameters for PET mass ratio is 10%, PLLA mass ratio is 5%, PET:PLLA=5:5, and the analysis of the infrared shows, in the nanoscale conditions, PET,PLLA and drug can not produce chemical reaction, maintaining their characteristics.Prepare the tapered corrugated artificial small blood vessels with different parameters by the created tapered corrugated collection devices, the conclusion is that the process of taking off the film form the device become easyer than before by the improved collection, which can adjust the helix number and helix angle,so as to reduce the chance thrombosis, besides,the inner surface is smooth and spiral grooves are continuous, which will help blood flow smoothly.Finally, do biomechanical testing and culture cell on artificial small diameter blood vessel samples,and the conclusion is that the helical corrugation can improve the bending behavior of the vascular graft obviously.With the thread number and taper angle increasing,the bending behavior of the vascular graft get worse.when the thread number is 4,the vascular graft can meet the requirement of which the state of the blood flow can remain stable and the bending behavior of the vascular graft is good, but the compliance small blood vessel compliance remains to be improved.The uviolizing and quantity of drug have a big influnce on the the state of cell growth on the samples. The corrugated state on the surface of the small blood vessel will effect the growth of cells in some extend, which still need to explore further.Simulate intravascular blood flow situation with the finite element software preliminarily,the simulation results show that the taper Angle and the isolation of blood will influnce corrugated velocity vector and pressure distributionl, with the increase of taper Angle and the increase of the ripples from, the two index become larger,which provides an initial direction for dynamic simulation experiment later.In summary, the small-diameter tapered and corrugated artificial blood vessel was prepared successfully. And the biomechanical property and the biocompatibility were verified through the relevent experiments. A new approach to improve the patency of small-diameter artificial blood vessel was provided. |
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