Chronoamperometry-Based Redox Cycling for Application to Immunoassays

Abstract

In this work, the chronoamperometry-based redox cycling of 3,3',5,5'-tetramethylbenzidine (TMB) was performed by using interdigitated electrode (IDE). The signal was obtained from two sequential chronoamperometric profiles: (1) with the generator at the oxidative potential of TMB and the collector at the reductive potential of TMB, and (2) with the generator at the reductive potential of TMB and the collector at the oxidative potential of TMB. The chronoamperometry-based redox cycling (dual mode) showed a sensitivity of 1.49 μA/OD, and the redox cycling efficiency was estimated to be 94% (n = 10). The sensitivities of conventional redox cycling with the same interdigitated electrode and chronoamperometry using a single working electrode (single mode) were estimated to be 0.67 μA/OD and 0.18 μA/OD, respectively. These results showed that the chronoamperometry-based redox cycling (dual mode) could be more effectively used to quantify the oxidized TMB than other amperometric methods. The chronoamperometry-based redox cycling (dual mode) was applied to immunoassays using a commercial ELISA kit for medical diagnosis of the human hepatitis B virus surface antigen (hHBsAg). Finally, the chronoamperometry-based redox cycling (dual mode) provided more than a 10-fold higher sensitivity than conventional chronoamperometry using a single working electrode (single mode) when applied to a commercial ELISA kit for medical diagnosis of hHBsAg.

Capacitive biosensor based on vertically paired electrodes for the detection of SARS-CoV-2

“…The IDE has been used for the analysis of capacitive changes that occur owing to the protein adsorption on IDEs ( Jung et al, 2014 ; Lee et al, 2018a ; Luka et al, 2019 ; Quoc et al, 2019 ). Usually, an IDE is composed of serially connected capacitors comprising electrodes and dielectric layers between electrodes.…”

“…The binding of analytes using the specific interactions between antigens and antibodies induced quantitative capacitive changes on the capacitive biosensors according to the bound analyte amount ( Chen et al 2019 , 2020 ; Tang et al, 2014 ). Such capacitive biosensors frequently use interdigitated electrodes (IDEs) as transducers with immobilized antibodies against target analytes ( Jung et al, 2014 ; Kim et al, 2021 ; Lee et al, 2018a ; Luka et al, 2019 ; Park et al, 2021 ; Quoc et al, 2019 ). The capacitance (C) measured from IDEs had the relation C = εㆍ N ㆍ A / d , where ε represents the permittivity constant, N represents the number of electrode pairs (for a single electrode pair, N=1), A represents the electrode area, and d represents the electrode gap.…”

A Label-Free Electrochemical Immunosensor for CEA Detection on a Novel Signal Amplification Platform of Cu2S/Pd/CuO Nanocomposites

“…The sensitivity of the unlabeled immunosensor mainly depends on the reducibility of the constructed material to H 2 O 2 (Yan et al, 2018). Chronoamperometry (i-t) can be used to compare the catalytic activities of different modified materials (Lee et al, 2018). As shown in Figure 4B, naked GCE has no catalytic activity for H 2 O 2 (curve a).…”

Advanced Solid State Nano-Electrochemical Sensors and System for Agri 4.0 Applications

“…By contrast, electrochemical sensors have a number of adventitious properties that make them particularly suitable for point-of-use applications. They are highly sensitive and portable, are relatively low cost, exhibit a rapid time-to-result, are highly versatile e.g., different, electrode materials (C, Au, Pt) are suitable for a variety of different chemical molecules, and may be modified with a large variety of biomolecules for bio-sensing applications [ 21 , 22 , 23 , 24 ]. Furthermore, they are low power and provide an electrical transduction signal, which may be fed directly into electronic systems (without conversion) amplified, undergo edge analytics with the resultant data sent to the cloud [ 25 , 26 ].…”