An essential step to control the virus spread in the COVID19 pandemic is to detect the new coronavirus SARS-CoV-2 accurately, specifically, and timely. While RT-PCR-based lab analysis and various fast-testing tools are increasingly accessible, most efforts have been limited to providing qualitative Yes/No answers. Quantitative information remains scarce, such as how the virus load per sample is correlated to the disease severeness, development over time, amond different populations, and the threshold of the virus presence (Yes or No) which affects the false negative (positive) among different methods/tools etc. This work describes an electrochemical detection platform based on in-situ signal amplification, in stark contrast to other tools that depend on sample amplifications. Gold microelectrodes are functionalized with designed nucleic acid probes that recognize specifically with the target RNA sequence/s. In the absence of the target viral RNAs, the recognition probes self fold into short loop structures and disconnect electron transfer pathways. Insignificant baseline current, i.e., ‘noise’, enables the detection of low signals or low abundance analyte. A signal-on mechanism is employed through the binding with the target RNA sequence which turns on the electron transduction pathway. Redox cycling, which is widely used in single entity electrochemistry, further enhances the detection signal. With pulse voltammetry technique readout, atto- to zepto-molar synthetic pure target sequences have been detected in minutes, with the dynamic range up to pico- to nano- molar (that can be further enhanced if needed). The validation of the sensor efficacy, in particular the interference in complex biomatrix, is underway.

Quantitation of SARS-CoV2 viral RNAs with microelectrode sensors

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.