Ding Jialian, Zhou Ping, Guo Weiliang, Su Bin
Department of Chemistry, Institute of Analytical Chemistry, Zhejiang University, Hangzhou, China.
Front Chem. 2021 Jan 26;8:630246. doi: 10.3389/fchem.2020.630246. eCollection 2020.
Electrochemiluminescence (ECL) imaging analysis based on the ultra-high-density microwell electrode array (UMEA) has been successfully used in biosensing and diagnostics, while the studies of ECL generation mechanisms with spatial resolution remain scarce. Herein we fabricate a gold-coated polydimethylsiloxane (PDMS) UMEA using electroless deposition method for the visualization of ECL reaction process at the single microwell level in conjunction with using microscopic ECL imaging technique, demonstrating that the microwell gold walls are indeed capable of enhancing the ECL generation. For the classical ECL system involving tris(2,2'-bipyridyl)ruthenium (Ru(bpy) ) and tri--propylamine (TPrA), the ECL image of a single microwell appears as a surface-confined ring, indicating the ECL intensity generated inside the well is much stronger than that on the top surface of UMEA. Moreover, at a low concentration of Ru(bpy) , the ECL image remains to be ring-shaped with the increase of exposure time, because of the limited lifetime of TPrA radical cations TPrA. In combination with the theoretical simulation, the ring-shaped ECL image is resolved to originate from the superposition effect of the mass diffusion fields at both microwell wall and bottom surfaces.
基于超高密度微孔电极阵列（UMEA）的电化学发光（ECL）成像分析已成功应用于生物传感和诊断领域，然而，具有空间分辨率的ECL产生机制的研究仍然很少。在此，我们使用化学沉积法制备了一种金涂层聚二甲基硅氧烷（PDMS）UMEA，结合微观ECL成像技术，用于在单个微孔水平上可视化ECL反应过程，证明微孔金壁确实能够增强ECL的产生。对于涉及三（2,2'-联吡啶）钌（Ru(bpy) ）和三丙胺（TPrA）的经典ECL体系，单个微孔的ECL图像呈现为表面受限的环，表明孔内产生的ECL强度远高于UMEA顶表面的强度。此外，在低浓度的Ru(bpy) 下，由于TPrA自由基阳离子TPrA的寿命有限，随着曝光时间的增加，ECL图像仍保持环形。结合理论模拟，解析出环形ECL图像源于微孔壁和底面质量扩散场的叠加效应。
