Podila Ramakrishna, Moore Thomas, Alexis Frank, Rao Apparao
Department of Physics, Clemson University, USA.
J Vis Exp. 2013 Mar 1(73):e50276. doi: 10.3791/50276.
Atomically smooth graphene as a surface coating has potential to improve implant properties. This demonstrates a method for coating nitinol alloys with nanometer thick layers of graphene for applications as a stent material. Graphene was grown on copper substrates via chemical vapor deposition and then transferred onto nitinol substrates. In order to understand how the graphene coating could change biological response, cell viability of rat aortic endothelial cells and rat aortic smooth muscle cells was investigated. Moreover, the effect of graphene-coatings on cell adhesion and morphology was examined with fluorescent confocal microscopy. Cells were stained for actin and nuclei, and there were noticeable differences between pristine nitinol samples compared to graphene-coated samples. Total actin expression from rat aortic smooth muscle cells was found using western blot. Protein adsorption characteristics, an indicator for potential thrombogenicity, were determined for serum albumin and fibrinogen with gel electrophoresis. Moreover, the transfer of charge from fibrinogen to substrate was deduced using Raman spectroscopy. It was found that graphene coating on nitinol substrates met the functional requirements for a stent material and improved the biological response compared to uncoated nitinol. Thus, graphene-coated nitinol is a viable candidate for a stent material.
原子级光滑的石墨烯作为一种表面涂层，有潜力改善植入物的性能。这展示了一种用纳米厚的石墨烯层涂覆镍钛诺合金的方法，用于作为支架材料。石墨烯通过化学气相沉积在铜基底上生长，然后转移到镍钛诺基底上。为了了解石墨烯涂层如何改变生物反应，研究了大鼠主动脉内皮细胞和大鼠主动脉平滑肌细胞的细胞活力。此外，用荧光共聚焦显微镜检查了石墨烯涂层对细胞粘附和形态的影响。细胞用肌动蛋白和细胞核进行染色，与涂覆石墨烯的样品相比，原始镍钛诺样品之间存在明显差异。使用蛋白质印迹法测定大鼠主动脉平滑肌细胞的总肌动蛋白表达。用凝胶电泳测定血清白蛋白和纤维蛋白原的蛋白质吸附特性，这是潜在血栓形成性的一个指标。此外，使用拉曼光谱推断纤维蛋白原向基底的电荷转移。结果发现，镍钛诺基底上的石墨烯涂层满足了支架材料的功能要求，与未涂覆的镍钛诺相比，改善了生物反应。因此，涂覆石墨烯的镍钛诺是一种可行的支架材料候选物。
