Study On The Fabrication Of Small-diameter Artificial Vascular Graft By Rapid Laser Fabrication Technology

Nowadays，cardiovascular and cerebrovascular diseases have replace cancerand respiratory diseases become the most common causes of morbidity and mortalityin patients all over the world. The most effective methods treating the disease arevascular repair, bypass, and reconstruction using the substitutes. The gold standardmaterial in bypass surgery of blood vessels remains the patient’s own artery or vein.However, this material may be unavailable, or may suffer vein graft disease, so cannot be used widely. Synthetic vascular prostheses, namely polyethylene terephthalate(PET, Dacron) and expanded polytetrafluoroethylene (ePTFE), perform well aslarge-caliber replacements, and have been used in clinical already. However, theirlong-term patency is discouraging in small-caliber applications. This failure is mainlya result of lacking of endothelial cells and anastomotic intimal hyperplasia caused byhemodynamic disturbances. So the research in the field of small-caliber vascularsubstitutes has become one focus of modern medicine.In this thesis, we introduce a novel method to fabricate small-caliber vasculargraft called rapid rotating exposure method. Focusing the UV light on the inner wallof a cylindrical mold, which is rotatable and transparent. Then, polymerize thepre-polymer in the mold using a UV-light under constant rotating. Bio-mimic micro-and nano structure was fabricated on the inner surface using a femtosecond laseramplifier, when the thickness of the polymer tube reached a certain value. Thestructure of the blood vessel is dynamic, complex, and cross-scale. Therefore, the bio-mimic structure is not only needed by the inner surface but also the outer.Polymeric systems with controlled patterns have attracted increasing interest inrecent years because of their wide range applications, such as microdevices, sensors,adhesives and biological cell studies. Here, we introduce a novel and relativelylow-cost, low-tech, self-wrinkling method to fabricate long-range order wrinklepattern based on a commonly used biocompatibility material, polymerized Poly(ethylene glycol)-diacrylate (PEGDA), which is a UV-curable liquid resin. Weattribute the unique performance to the competition of the bending of the skin andcompressing of the bulk of PEGDA hydrogel film. In particular, the spontaneouspatterns can not only formed on planar substrates but also curved substrates. Theprinciple of self-assembled buckling patterns of hydrogel flms on curved substrateswas used for the morphogenesis of the outer surface of the polymer tube. Thestructured surface is conducive to the adsorption of endothelial cells and smoothmuscle cells. As a result, the graft consist of a functional endothelial cell layer willimprove the long-time patency obviously.The fabricated small-caliber vascular graft is biocompatibility due to theinherent biocompatibility of PEGDA and the bionic structure. It is expected to be usedin clinical trial via a further research.