Department of Chemistry, Renmin University of China, Beijing, P R China.
Anal Chem. 2011 Aug 15;83(16):6426-30. doi: 10.1021/ac200939g. Epub 2011 Jul 27.
In this study, we develop a new technique to fabricate a reduced graphene oxide (rGO)-based microelectrode array (MEA) with low-cost soft lithography. To prepare patterned rGO, a polydimethylsiloxane (PDMS) mold with an array of microwells on its surface is fabricated using soft lithography, and GO is assembled on an indium tin oxide (ITO) electrode with a layer-by-layer method. The rGO pattern is formed by closely contacting the assembled GO film onto the ITO electrode with the PDMS mold filled with hydrazine solution in the microwells to selectively reduce the localized GO into the rGO. The MEA with patterned rGO as the microelectrode is characterized with Kelvin probe force microscopy (KFM), atomic force microscopy (AFM), and cyclic voltammetry (CV) with ferricyanide in aqueous solution as the redox probe. The KFM and AFM results demonstrate that each rGO pattern prepared under the present conditions is 3 μm in diameter, which is close to that of the PDMS mold we use. The CV results show that the rGO patterned onto the ITO exhibits a sigmoid-shaped voltammogram up to 200 mVs(-1) with a microampere level current response, suggesting that the rGO-based electrode fabricated with soft lithography behalves like a MEA. To demonstrate the potential electroanalytical application of the rGO-based MEA, prussian blue (PB) is electrodeposited onto the rGO-based MEA to form the PB/rGO-based MEA. Electrochemical studies on the formed PB/rGO-based MEA reveal that MEA shows a lower detection limit and a larger current density for the detection of H(2)O(2), as compared with the macroscopic rGO electrode. The method demonstrated here provides a simple and low-cost strategy for the fabrication of graphene-based MEA that are useful for electroanalytical applications.
在这项研究中，我们开发了一种新的技术，使用低成本的软光刻技术制造基于还原氧化石墨烯（rGO）的微电极阵列（MEA）。为了制备图案化的 rGO，使用软光刻技术制造了具有表面微凹阵列的聚二甲基硅氧烷（PDMS）模具，并且通过层层法将 GO 组装到氧化铟锡（ITO）电极上。通过将组装好的 GO 薄膜紧密接触到充满水合肼溶液的微凹 PDMS 模具中的 ITO 电极上，可以形成 rGO 图案，从而选择性地将局部 GO 还原为 rGO。使用 Kelvin 探针力显微镜（KFM）、原子力显微镜（AFM）和以水溶液中的铁氰化物作为氧化还原探针的循环伏安法（CV）对具有图案化 rGO 作为微电极的 MEA 进行了表征。KFM 和 AFM 结果表明，在当前条件下制备的每个 rGO 图案的直径均为 3 μm，接近我们使用的 PDMS 模具的直径。CV 结果表明，在 ITO 上图案化的 rGO 表现出高达 200 mV s(-1)的类正弦形伏安图，具有微安培级的电流响应，表明使用软光刻技术制造的 rGO 基电极表现得像 MEA。为了证明 rGO 基 MEA 的潜在电分析应用，将普鲁士蓝（PB）电沉积到 rGO 基 MEA 上以形成 PB/rGO 基 MEA。对形成的 PB/rGO 基 MEA 的电化学研究表明，与宏观 rGO 电极相比，MEA 对 H(2)O(2)的检测具有更低的检测限和更大的电流密度。这里展示的方法为制造适用于电分析应用的基于石墨烯的 MEA 提供了一种简单且低成本的策略。
