Electrogenerated Chemiluminescence Reporting on Closed Bipolar Microelectrodes and the Influence of Electrode Size

Abstract

We report a fundamental study of the use of Ru(bpy)32+-based electrogenerated chemiluminescence (ECL) as an optical reporting system for the detection of redox-active analyte on closed bipolar microelectrodes, focused on gaining an in-depth understanding of the correlation between ECL emission intensity and electrochemical current. We demonstrate the significant effect that the size of the anodic and cathodic poles has on the resulting ECL signal and show how this influences the quantitative detection of analyte on a closed bipolar electrode. By carefully designing the geometry of the bipolar electrode, the detection performance of the system can be tuned to different analyte concentration ranges. We show that through a simple voltammetric study of the individual reactions, one can understand the coupled bipolar behavior and accurately predict the ECL signal response to a range of analyte concentrations, enabling the accurate prediction of calibration curves.

Utilization of an Electrochemiluminescence Sensor for Atropine Determination in Complex Matrices

“…In addition to the increase in signal, a shift in potential is observed as atropine concentration increases. This shift, although unexpected, can likely be attributed to a combination of the following effects: first, the ruthenium becomes the rate limiting reagent, where the Ru 3+ centers are more rapidly consumed than produced via heterogeneous oxidation at the electrode surface . Second, a slight shift in pH at the electrode surface as a result of the increased concentration of the electrogenerated byproducts: noratropine and formaldehyde.…”

“…This shift, although unexpected, can likely be attributed to a combination of the following effects: first, the ruthenium becomes the rate limiting reagent, where the Ru 3+ centers are more rapidly consumed than produced via heterogeneous oxidation at the electrode surface. 45 Second, a slight shift in pH at the electrode surface as a result of the increased concentration of the electrogenerated byproducts: noratropine and formaldehyde. This is consistent with previous work, which saw a shift in the λ ECLmax at a graphite electrode, 46 highlighting the impact that pH can have.…”

Advances in bipolar electrochemiluminescence for the detection of biorelevant molecular targets

“…This is also true in the case of ECL reporting in the closed-configuration because the size and geometry (i.e. surface area) of both sensing and reporting poles may affect the overall ECL strength [43].…”

Microscale and Nanoscale Electrophotonic Diagnostic Devices

“…Zhang and co-workers demonstrated fluorescence-enabled CBE assays, which has proven to be capable of recording the transient extracellular vesicle release of neurotransmitter molecules, e.g. dopamine (Cox et al 2012; Oja Stephen and Zhang 2015). Xu and co-workers used ECL-based CBEs to detect several important biomarkers, including HL-60 tumor cells (Zhang et al 2016a), and prostate-specific antigen (Wu et al 2015).…”