仿生电信号血管材料调控血管组织再生与功能稳态的作用研究

There is clear and unmet clinical need to develop functionally superior small-diameter artificial vascular grafts for blood vessel tissue regeneration. Bio-electricity plays an important role in maintaining normal tissue physiological functionality and has been shown to improve the repair of injured tissues. Various applications of bio-electrical factors in bone, heart, and other tissue engineering scaffolds, have proven effective in promoting tissue regeneration. However, the incorporation of bio-electrical factors in the construction of vascular grafts and the considerations of the roles of electrical stimulation on vascular regeneration in this context, have yet to be studied. Therefore, in this study, we aim to measure the piezoelectric coefficient of native artery vessels and analyze the characteristics of generated electrical signals, thus providing parameters to match for the incorporation of bio-electric factors into vascular grafts. Next, we will use pziezoelectric polymers to prepare small-diameter vascular grafts capable of releasing electrical signals comparable to the natural artery tissue. Grafts will be fabricated and optimized through the combined use of electrostatic spinning, melt-spinning and wet-spinning. The regulating effect and action mechanism of electrical stimulation released by piezoelectric vascular grafts on the behavior of vascular cells and macrophages will be studied by using dynamic culture devices. Finally, the animal models for vascular implantation model will be used to evaluate the influence of electrical stimulation released by piezoelectric vascular grafts on vascular patency and tissue regeneration. The regulatorying effects and its signal transduction mechanisms resulting from of electrical stimulation relating to the in regulation of vascular regeneration will can be systematically clarified through the in vivo and in vitro experiments. The implementation of this project will provide a new concept for the construction of small-diameter artificial vascular graft and help promote their development toward clinical studies.

研发可用于替换受损/堵塞血管的小口径人工血管具有重要意义。生物电对许多组织的功能维持和损伤修复起重要的调控作用。在构建骨、心脏等支架时引入生物电因素均能有效促进组织再生。但人工血管的构建是否需要考虑生物电因素，以及电刺激在血管再生与功能稳态维持中的作用尚无研究。因此，本项目拟对小口径动脉血管的压电系数及其释放的电信号特征进行分析，为血管材料引入生物电因素提供参数依据。然后，以压电聚合物为原料，通过静电纺丝、熔融纺丝与湿法纺丝技术的单独或联合使用，制备可仿生天然动脉电信号的压电小口径血管材料。在动态培养下，研究压电血管材料释放电刺激对血管细胞和巨噬细胞行为的调控作用及其作用机制。通过动物体内移植，研究压电血管材料释放电刺激对血管组织再生与功能稳态维持的影响。通过体、内外实验的相互验证系统阐明电刺激调控血管再生的信号传导机制。该项目的实施将为血管损伤修复提供新型的小口径人工血管。

在骨、心脏等修复材料中引入生物电因素已经取得了有效的促再生效果，但是人工血管的构建是否需要考虑生物电因素，以及电刺激在血管再生的作用尚无研究。压电材料是一种具有压电效应的智能材料，能够实现机械信号与电信号的转换。为此，我们以压电聚合物聚偏二氟乙烯-三氟乙烯[P(VDF-TrFE)]为原料，采用静电纺丝技术构建了具有压电效应的P(VDF-TrFE)人工血管，该压电血管体内植入后能够将血液压力转化成电信号。我们通过改变后处理退火温度调控血管材料结晶度、β相含量以及C-F键构象，进而阐明了P(VDF-TrFE)血管材料结晶度与力学性能、P(VDF-TrFE) 血管材料β相含量与压电性和P(VDF-TrFE) 血管材料C-F键构象与表面电势的构效关系。由于P(VDF-TrFE)的压电性无法被完全消除，我们选择不具有压电效应的聚己内酯（PCL）作为对照材料。通过纺丝参数的调控，我们制备了与电纺P(VDF-TrFE)血管材料在纤维直径，孔径，壁厚，力学特性以及亲疏水性上具有相同特征的电纺PCL血管材料作为对照组，既对照组电纺PCL血管材料与电纺P(VDF-TrFE)血管材料仅在电学性能上有所差异。通过AV-Shunt等实验，我们发现带有强的负表面电势的P(VDF-TrFE)血管材料能够通过静电排斥作用防止带负电荷的血小板、红细胞等凝血基质在纤维表面粘附，有效提高材料的血液相容性。我们通过大鼠腹主动脉血管移植实验研究了血管材料在体内释放的电信号的生物学作用，结果表明压电刺激有效促进了血管再生。我们通过Flexcell-5000T细胞应力加载系统模拟血管材料在体内的形变，施加形变以使P(VDF-TrFE)膜释放电信号，通过该方法证实了压电刺激调整了血管内皮细胞生长因子（VEGF）的可变剪切，进而促进了内皮细胞增殖与迁移。本项目的实施证实了电信号刺激有利于人工血管再生，推动了人工血管的发展。