Simulation of Fast-Scan Nanogap Voltammetry at Double-Cylinder Ultramicroelectrodes.
Simulation of Fast-Scan Nanogap Voltammetry at Double-Cylinder Ultramicroelectrodes.
复制标题
DOI：
10.1149/2.0051812jes
复制
发表时间：
2018
影响因子：
3.9
通讯作者：
Pavithra Pathirathna;Ryan J Balla;S. Amemiya
中科院分区：
文献类型：
--
作者：
Pavithra Pathirathna;Ryan J Balla;S. Amemiya
快速扫描循环伏安法（FSCV）具有很高的时间分辨率，在基础电化学和应用电化学中被广泛应用，可以利用超微电极（UME）定量研究电子传递和神经传递的快速动力学过程。然而，更快的电位扫描线性地增加背景电流，其必须被减去以用于定量FSCV。在这里，我们数值模拟快速扫描纳米间隙伏安法（FSNV）的定量检测扩散氧化还原物种下的准稳态，而不需要背景扣除，同时保持高的时间分辨率的瞬态FSCV。FSNV的这些优点源自于与具有单个UME的FSCV相比，使用具有纳米宽间隔的平行对圆柱形UME。在FSNV中，跨纳米间隙的扩散氧化还原循环在发生器电极处被伏安法驱动，并且在集电极处被安培法监测，而没有瞬态背景。我们发现，圆柱形集电极可以达到准稳态~104倍的速度比具有相同尺寸的发生器电极，以允许快速扫描。双微柱体和纳米柱体UME分别实现了如针对体内FSCV实践的每秒数百伏和如针对超FSCV实现的每秒兆伏的准稳态FSNV。提出了合理设计和简单制作的双圆柱体微电极，以拓宽纳米间隙伏安法的应用。
High temporal resolution of fast-scan cyclic voltammetry (FSCV) is widely appreciated in fundamental and applied electrochemistry to quantitatively investigate rapid dynamics of electron transfer and neurotransmission using ultramicroelectrodes (UMEs). Faster potential scan, however, linearly increases the background current, which must be subtracted for quantitative FSCV. Herein, we numerically simulate fast-scan nanogap voltammetry (FSNV) for quantitative detection of diffusing redox species under quasi-steady states without the need of background subtraction while maintaining high temporal resolution of transient FSCV. These advantages of FSNV originate from the use of a parallel pair of cylindrical UMEs with nanometer-wide separation in contrast to FSCV with single UMEs. In FSNV, diffusional redox cycling across the nanogap is driven voltammetrically at the generator electrode and monitored amperometrically at the collector electrode without the transient background. We reveal that the cylindrical collector electrode can reach quasi-steady states ~104 times faster than the generator electrode with identical sizes to allow for fast scan. Double-microcylinder and nanocylinder UMEs enable quasi-steady-state FSNV at hundreds volts per second as practiced for in-vivo FSCV and megavolts per second as achieved for ultra-FSCV, respectively. Rational design and simple fabrication of double-cylinder UMEs are proposed to broaden the application of nanogap voltammetry.