Electrochemical RT-PCR detection for COVID-19

Welcome to our discussion on the electrochemical detection of COVID-19 using reverse transcription polymerase chain reaction (PCR).


Though PCR is entering the widely used lexicon it is not always understood; a simple definition of PCR is a method by which DNA can be amplified so that it can subsequently detected or measured. The term amplification in this context means that the amount of DNA is increased (multiplied) by the polymerase chain reaction.


There is a hyphenated version of PCR, which is relevant when discussing COVID-19, this is real time PCR, also known as quantitative PCR (qPCR). In qPCR it is possible to measure the amount DNA as a function of time/cycles.  The time it takes for DNA to be detected is proportional to the amount of target DNA in the original sample and so the real-time PCR/qPCR can be a quantitative. 


Of course, COVID-19 a virus and hence has RNA as opposed to DNA. Therefore, when you look at the tests on the market for the detection of an active COVID-19 infection many are best described as RT-PCR, where the RT stands for reverse transcriptase. The sequence of events in aCOVID-19 RT-PCR is that the COVID-19 RNA first undergoes transcription from RNA to DNA, and subsequently the DNA is amplified (multiplied) and in real time the amplification of the DNA is measured.


A flaw in RT-PCR detection of COVID-19 is that it often involves a fluorescent t dye, and it is the binding of this dye to the amplified DNA from the PCR, which is the source of the signal. The issue is that it is hard to make fluorescent base instruments low cost and portable. When you look at the list of commercial fluorescent-based RT-PCR instruments for COVID-19 the smallest are tabletop units, and none can be described as handheld and low cost.


What is required is a small handheld COVID-19 RT-PCR instrument with the same costs and size as a glucose meter.  In order to achieve this the detection science has to be transferred from fluorescence to electrochemistry. All handheld glucose meters on the market are based on the science of bio-electrochemistry, which allows them to be manufactured at relatively low prices.


To convert a fluorescence RT-PCR to an electrochemical RT-PCR is straightforward with a lot of examples in the literature, and a simple google search on ‘electrochemical RT-PCR’ will yield pages of academic hits.


At ZP we have a number of technologies available through our webstore to help those wishing to develop low cost RT-PCR COVID-19 tests using electrochemistry, please don’t hesitate to contact us.