Single Frequency Impedance Analysis on Reduced Graphene Oxide Screen-Printed Electrode for Biomolecular Detection

Abstract

A biofunctionalized reduced graphene oxide (rGO)-modified screen-printed carbon electrode (SPCE) was constructed as an immunosensor for C-reactive protein (CRP) detection, a biomarker released in early stage acute myocardial infarction. A different approach of single frequency analysis (SFA) study was utilized for the biomolecular sensing, by monitoring the response in phase angle changes obtained at an optimized frequency resulting from antigen-antibody interactions. A set of measurements were carried out to optimize a frequency where a maximum change in phase angle was observed, and in this case, we found it at around 10 Hz. The bioelectrode was characterized by contact angle measurements, scanning electron microscopy, and electrochemical techniques. A concentration-dependent response of immunosensor to CRP with the change in phase angle, at a fixed frequency of 10 Hz, was found to be in the range of 10 ng mL to 10 μg mL in PBS and was fit quantitative well with the Hill-Langmuir equation. Based on the concentration-response data, the dissociation constant (K ) was found to be 3.5 nM (with a Hill coefficient n = 0.57), which indicated a negative cooperativity with high anti-CRP (antibody)-CRP (antigen) binding at the electrode surface. A low-frequency analysis of sensing with an ease of measurement on a disposable electroactive rGO-modified electrode with high selectivity and sensitivity makes it a potential tool for biological sensors.

Design and Electrochemical Characterization of Spiral Electrochemical Notification Coupled Electrode (SENCE) Platform for Biosensing Application

“…Generally, electrodes are diversified into different categories based on design, component, and material. Screen-printed three-electrode assemblies with materials like gold, graphene, and carbon are very popular among the scientific community [21]. Bias is applied between the working electrode (WE) and a reference electrode (RE) to get a signature signal output with high sensitivity.…”

Label-Free Electrochemical Immunosensor Based on Conjugated Polymer Film Coated Disposable Electrode for Ultrasensitive Determination of Resistin Potential Obesity Biomarker

“…SFI is an impedance analysis process where a constant frequency is utilized as an induced signal in place of a wide frequency range. This method reduces the complication in signal attainment and processing, and thus a favorable, easy, and low-cost analysis is performed . In this analysis, impedance was recorded at a constant frequency obtained by Bode plot, and impedance changes were monitored in phosphate buffer containing target antigen .…”

Screen-printed carbon electrode/natural silica-ceria nanocomposite for electrochemical aptasensor application

“…Typically, ENaC protein is detected by enzyme-linked immunosorbent assay (ELISA) [4,32], but this method is time consuming and expensive [27]. Immunosensors can detect low levels of ENaC [3,31] since using antibodies as bioreceptors is highly selective and sensitive [33].…”