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  • In Situ and 2D and 3D in Silico Redox Cycling Studies for Design Optimization of Coplanar Arrays of Microband Electrodes in a 70 μm × 100 μm Electroactive Footprint
Title: In Situ and 2D and 3D in Silico Redox Cycling Studies for Design Optimization of Coplanar Arrays of Microband Electrodes in a 70 μm × 100 μm Electroactive Footprint
Optimization of redox-cycling currents was performed by adjusting the height (sidewalls,h), width (w), and length (l) of band electrodes and their spacing (wgap) in coplanar arrays restricted to a small-electroactive window of 70 × 100μm. These arrays can function inμL-volumes for chemical analysis (e.g., in-vivo dopamine detection using probes). Experiments were conducted with an array of five electrodes (NE= 5),w= 4.3μm,wgap= 3.7μm,h= 0.150μm, andl= 99.2μm. Reasons for disparities between currents from experiments and approximate equations were determined by high-density mesh simulations and were found to arise from sluggish heterogeneous electron transfer kinetics and diffusion at electrode ends, edges, and heights. Ferricyanide, with its moderately slow kinetics, exhibits redox-cycling currents that fall below predictions by the equations aswgapdecreases and diffusional flux outpaces reaction rates. Simulations aid investigations of various array designs, achievable through conventional photolithography, by decreasingwandwgapand increasingNEto fit within the electroactive window. A coplanar array,NE= 58,w=wgap= 0.6μm,h= 0.150μm andl= 100μm, yielded ferricyanide sensitivities of 0.266, 0.259 nA·μM−1, enhancements of 8 × and 9 × overw=wgap= 4μm, and projected dopamine lower limits of quantitation of 139 nM, 171 nM at generator and collector electrodes, respectively.  more » « less
Award ID(s):
1808286
PAR ID:
10519709
Author(s) / Creator(s):
; ;
Publisher / Repository:
The Electrochemical Society
Date Published:
Journal Name:
Journal of The Electrochemical Society
Volume:
171
Issue:
6
ISSN:
0013-4651
Format(s):
Medium: X Size: Article No. 066512
Size(s):
Article No. 066512
Sponsoring Org:
National Science Foundation
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