Jones John Eric, Yu Qingsong, Chen Meng
a Department of Mechanical & Aerospace Engineering , Center for Surface Science and Plasma Technology, University of Missouri , Columbia , MO , USA.
b Nanova, Inc. , Columbia , MO , USA.
J Biomater Sci Polym Ed. 2017 Jan;28(1):15-32. doi: 10.1080/09205063.2016.1239947. Epub 2016 Oct 19.
Trimethylsilane (TMS) plasma nanocoatings were deposited onto stainless steel coupons in direct current (DC) and radio frequency (RF) glow discharges and additional NH/O plasma treatment to tailor the coating surface properties. The chemical stability of the nanocoatings were evaluated after 12 week storage under dry condition (25 °C) and immersion in simulated body fluid (SBF) at 37 °C. It was found that nanocoatings did not impact surface roughness of underlying stainless steel substrates. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy were used to characterize surface chemistry and compositions. Both DC and RF nanocoatings had Si- and C-rich composition; and the O- and N-contents on the surfaces were substantially increased after NH/O plasma treatment. Contact angle measurements showed that DC-TMS nanocoating with NH/O treatment generated very hydrophilic surfaces. DC-TMS nanocoatings with NH/O treatment showed minimal surface chemistry change after 12 week immersion in SBF. However, nitrogen functionalities on RF-TMS coating with NH/O post treatment were not as stable as in DC case. Cell culture studies revealed that the surfaces with DC coating and NH/O post treatment demonstrated substantially improved proliferation of endothelial cells over the 12 week storage period at both dry and wet conditions, as compared to other coated surfaces. Therefore, DC nanocoatings with NH/O post treatment may be chemically stable for long-term properties, including shelf-life storage and exposure to the bloodstream for coronary stent applications.
在直流（DC）和射频（RF）辉光放电条件下，将三甲基硅烷（TMS）等离子体纳米涂层沉积在不锈钢试样上，并进行额外的NH/O等离子体处理以调整涂层表面性能。在25℃干燥条件下储存12周以及在37℃模拟体液（SBF）中浸泡后，评估纳米涂层的化学稳定性。发现纳米涂层不会影响底层不锈钢基材的表面粗糙度。使用X射线光电子能谱和傅里叶变换红外光谱对表面化学和组成进行表征。直流和射频纳米涂层均富含硅和碳；经过NH/O等离子体处理后，表面的氧和氮含量大幅增加。接触角测量表明，经过NH/O处理的直流-TMS纳米涂层产生了非常亲水性的表面。经过NH/O处理的直流-TMS纳米涂层在SBF中浸泡12周后，表面化学变化最小。然而，经过NH/O后处理的射频-TMS涂层上的氮官能团不如直流情况下稳定。细胞培养研究表明，与其他涂层表面相比，在干燥和潮湿条件下储存12周期间，具有直流涂层和NH/O后处理的表面显示出内皮细胞增殖的显著改善。因此，经过NH/O后处理的直流纳米涂层在长期性能方面可能具有化学稳定性，包括保质期储存以及用于冠状动脉支架应用时暴露于血液中。
