Chen Chaozhan, Ran Bin, Wang Zhenxing, Zhao Hongli, Lan Minbo, Chen Huaying, Zhu Yonggang
School of Science, Harbin Institute of Technology, Shenzhen Shenzhen 518055 China.
Shanghai Key Laboratory of Functional Materials Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology Shanghai 200237 PR China.
RSC Adv. 2020 Nov 10;10(67):41110-41119. doi: 10.1039/d0ra07694e. eCollection 2020 Nov 9.
Micropillar array electrodes (μAEs) have been widely applied in electrochemical detection owing to their advantages of increased mass transport, lower detection limit, and potential to be miniaturized. This paper reports the fabrication, simulation, surface modification, and characterization of PDMS-based μAEs coated with gold films. The μAEs consist of 9 × 10 micropillars with a height of either 100 μm, 300 μm, or 500 μm in a 0.09 cm region. Numerical simulation was employed to study the influence of geometrical parameters on the current density. The μAEs were fabricated by soft lithography and characterized using both SEM and cyclic voltammetry. Experiments revealed that high pillars enabled enhanced voltammetric current density regardless of the scan rates. The platinum-palladium/multi-walled carbon nanotubes (Pt-Pd/MWCNTs) were coated on the μAEs to improve their electrochemical detection capability. The μAEs demonstrated 1.5 times larger sensitivity compared with the planar electrode when hydrogen peroxide was detected. Furthermore, μAE500 with Pt-Pd/MWCNTs was employed to detect sarcosine, a potential biomarker for prostate cancer. The linear range and limit of detection for sarcosine were from 5 to 60 μM and 1.28 μM, respectively. This detection range covers the concentration of sarcosine in human tissues (0-60 μM). These results suggest that the μAEs have better detection performance in comparison to planar electrodes due to their large surface area and pillar height. This paper provides essential guidelines for the application of μAEs in high sensitivity electrochemical detection of low abundance analytes.
微柱阵列电极（μAEs）因其在传质增强、检测限降低以及易于小型化等方面的优势，已在电化学检测中得到广泛应用。本文报道了涂覆金膜的基于聚二甲基硅氧烷（PDMS）的μAEs的制备、模拟、表面修饰及表征。μAEs由9×10个微柱组成，在0.09平方厘米的区域内，微柱高度分别为100μm、300μm或500μm。采用数值模拟研究几何参数对电流密度的影响。μAEs通过软光刻技术制备，并使用扫描电子显微镜（SEM）和循环伏安法进行表征。实验表明，无论扫描速率如何，高微柱均能提高伏安电流密度。在μAEs上涂覆铂钯/多壁碳纳米管（Pt-Pd/MWCNTs）以提高其电化学检测能力。在检测过氧化氢时，μAEs的灵敏度比平面电极高1.5倍。此外，采用涂覆有Pt-Pd/MWCNTs的μAE500检测肌氨酸，肌氨酸是前列腺癌的一种潜在生物标志物。肌氨酸的线性范围和检测限分别为5至60μM和1.28μM。该检测范围涵盖了人体组织中肌氨酸的浓度（0 - 60μM）。这些结果表明，由于其较大的表面积和柱高，μAEs与平面电极相比具有更好的检测性能。本文为μAEs在低丰度分析物的高灵敏度电化学检测中的应用提供了重要指导。
