Choi Jong Seob, Smith Alec S T, Williams Nisa P, Matsubara Tatsuya, Choi Minji, Kim Joon-Wan, Kim Hyung Jin, Choi Seungkeun, Kim Deok-Ho
Department of Biomedical Engineering and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, United States.
Department of Bioengineering, University of Washington, 850 Republican Street, Seattle, WA 98109, United States.
Adv Funct Mater. 2020 Jun 18;30(25). doi: 10.1002/adfm.201910660. Epub 2020 Apr 22.
In this study, we report nanopatterned Nafion microelectrode arrays for in vitro cardiac electrophysiology. With the aim of defining sophisticated Nafion nanostructures with highly ionic conductivity, fabrication parameters such as Nafion concentration and curing temperature were optimized. By increasing curing temperature and Nafion concentration, we were able to control the replication fidelity of Nafion nanopatterns when copied from a PDMS master mold. We also found that cross-sectional morphology and ion current density of nanopatterned Nafion strongly depends on the fabrication parameters. To investigate this dependency, current-voltage analysis was conducted using organic electrochemical transistors (OECT) overlaid with patterned Nafion substrates. Nanopatterned Nafion was found to allow higher ion current densities than unpatterned surfaces. Furthermore, higher curing temperatures were found to render Nafion layers with higher ion/electrical transfer properties. To optimize nanopattern dimensions, electrical current flows, and film uniformity, a final configuration consisting of 5% nanopatterned Nafion cured at 65°C was chosen. Multielectrode arrays (MEAs) were then covered with optimized Nafion nanopatterns and used for electrophysiological analysis of two types of induced pluripotent stem cell-derived cardiomyocytes (iPSCs-CMs). These data highlight the suitability of nanopatterned Nafion, combined with MEAs, for enhancing the cellular environment of iPSC-CMs for use in electrophysiological analysis .
在本研究中，我们报道了用于体外心脏电生理学的纳米图案化的Nafion微电极阵列。为了定义具有高离子传导率的精密Nafion纳米结构，我们优化了诸如Nafion浓度和固化温度等制造参数。通过提高固化温度和Nafion浓度，我们能够在从PDMS母模复制时控制Nafion纳米图案的复制保真度。我们还发现，纳米图案化Nafion的横截面形态和离子电流密度强烈依赖于制造参数。为了研究这种依赖性，我们使用覆盖有图案化Nafion基板的有机电化学晶体管（OECT）进行了电流-电压分析。发现纳米图案化的Nafion比未图案化的表面允许更高的离子电流密度。此外，发现更高的固化温度会使Nafion层具有更高的离子/电传输特性。为了优化纳米图案尺寸、电流流动和膜均匀性，选择了由在65°C固化的5%纳米图案化Nafion组成的最终配置。然后将多电极阵列（MEA）覆盖上优化的Nafion纳米图案，并用于两种诱导多能干细胞衍生的心肌细胞（iPSC-CM）的电生理分析。这些数据突出了纳米图案化Nafion与MEA相结合在增强用于电生理分析的iPSC-CM细胞环境方面的适用性。
