Lee Hwi Yong, Barber Cedrick, Minerick Adrienne R
Department of Chemical Engineering, Michigan Technological University, Houghton, MI, USA.
Electrophoresis. 2015 Aug;36(15):1666-73. doi: 10.1002/elps.201500227. Epub 2015 Jul 14.
Many microfluidic devices, also known as lab-on-a-chip devices, employ electrochemical detection methods using microelectrodes. Miniaturizing electrodes inevitably reduces electrode sensitivity and decreases the S/N, which limits applications within microfluidic devices. However, microelectrode surface modification can increase the surface area and sensitivity. In the present work, we report substantial improvement in platinum electrode performance and sensitivity by coating with carbon from red blood cells. The larger goal of this work was to measure DC electrical resistances of red blood cell suspensions in a microchannel for hematocrit determination. It was observed that as current responses of red blood cell suspensions were measured, the platinum electrode performance (reproducibility and S/N) improved with time. The platinum electrode electrocatalytic activity for red blood cell current measurements improved by 140%. Systematic experimentation revealed that red blood cells adsorb and carbonize the platinum electrode surfaces. The electrode surfaces before and after performance improvements were analyzed by field emission scanning electron microscopy, energy dispersive spectrometry, and Raman spectrometry. The formed carbon layers on the electrode surfaces were found to be proteomic and increased surface area with a porous three-dimensional structure, thus improving performance and stabilizing currents.
许多微流控设备，也被称为芯片实验室设备，采用使用微电极的电化学检测方法。电极小型化不可避免地会降低电极灵敏度并减小信噪比，这限制了微流控设备中的应用。然而，微电极表面修饰可以增加表面积和灵敏度。在本工作中，我们报告了通过用来自红细胞的碳进行涂层，铂电极性能和灵敏度有了显著提高。这项工作的更大目标是测量微通道中红细胞悬浮液的直流电阻以确定血细胞比容。观察到在测量红细胞悬浮液的电流响应时，铂电极性能（重现性和信噪比）随时间而改善。用于红细胞电流测量的铂电极电催化活性提高了140%。系统实验表明红细胞吸附并碳化铂电极表面。通过场发射扫描电子显微镜、能量色散光谱和拉曼光谱对性能改进前后的电极表面进行了分析。发现电极表面形成的碳层具有蛋白质组学特性，并且具有多孔三维结构，增加了表面积，从而提高了性能并稳定了电流。
