Impedimetric Sensing: An Emerging Tool for Combating the COVID-19 Pandemic

Abstract

The COVID-19 pandemic revealed a pressing need for the development of sensitive and low-cost point-of-care sensors for disease diagnosis. The current standard of care for COVID-19 is quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). This method is sensitive, but takes time, effort, and requires specialized equipment and reagents to be performed correctly. This make it unsuitable for widespread, rapid testing and causes poor individual and policy decision-making. Rapid antigen tests (RATs) are a widely used alternative that provide results quickly but have low sensitivity and are prone to false negatives, particularly in cases with lower viral burden. Electrochemical sensors have shown much promise in filling this technology gap, and impedance spectroscopy specifically has exciting potential in rapid screening of COVID-19. Due to the data-rich nature of impedance measurements performed at different frequencies, this method lends itself to machine-leaning (ML) algorithms for further data processing. This review summarizes the current state of impedance spectroscopy-based point-of-care sensors for the detection of the SARS-CoV-2 virus. This article also suggests future directions to address the technology’s current limitations to move forward in this current pandemic and prepare for future outbreaks.

An overview of electrochemical biosensors used for COVID-19 detection

“…This type of biosensor can reach low detection limits, is less reactive and takes less time compared to RT-PCR, presenting great potential for large-scale production. 60,61,70,83 An innovation in the area of electrochemical biosensors is the possibility of not using probes in the detection process, but rather materials that undergo redox reactions on their own, making the process more economical. Biosensors without the use of probes such as the ferri/ferrocyanide pair and methylene blue are described below.…”

“…The impedance can be obtained in the presence or absence of a redox couple, which indicates whether the impedance is faradaic or non-faradaic, respectively. 60,61 In faradaic biosensors, also known as impedimetric biosensors, the antibodies are immobilized on the electrodes. The electrode is then coated with a blocking layer, resulting in a change in electron transfer.…”

Sustainable agriculture with LEAFS: a low-cost electrochemical analyzer of foliage stress

“…The challenges related to these methods, including sensitivity to interference, limitations in sensitivity, and the need for specialized knowledge, also have driven for alternative methods, like electrochemistry. [18][19][20] Electrochemical analysis offers high sensitivity and selectivity, [21][22][23][24][25] ensuring accurate detection from complex plant matrices. Additionally, the rapidity of electrochemical reactions enables fast detection, 26 and their costeffectiveness, coupled with portability, also makes them particularly attractive.…”

“…Electrochemical analysis offers high sensitivity and selectivity, 21–25 ensuring accurate detection from complex plant matrices. Additionally, the rapidity of electrochemical reactions enables fast detection, 26 and their cost-effectiveness, coupled with portability, also makes them particularly attractive.…”

Effect of Applied AC Voltage on the Performance of Non-Faradaic Impedimetric Biosensors

“…They have been used for the detection of a variety of diseases including chronic diseases and infectious diseases. [1][2][3][4][5] Unlike other electrochemical methods, EIS provides a complete description of the antibody/antigen interaction at the electrode/electrolyte interface. EIS translates such interaction to an impedimetric measurement over a wide frequency range.…”