eCovSens-Ultrasensitive Novel In-House Built Printed Circuit Board Based Electrochemical Device for Rapid Detection of nCovid-19 antigen, a spike protein domain 1 of SARS-CoV-2

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, also known as 2019-nCov or nCovid-19) outbreak has become a huge public health issue due to its rapid transmission making it a global pandemic. Currently, there are no vaccines or drugs available for nCovid-19, hence early detection is crucial to help and manage the outbreak. Here, we report an inhouse built biosensor device (eCovSens) and compare it with a commercial potentiostat machine for the detection of nCovid-19 spike protein antigen (nCovid-19 Ag) in spiked saliva samples. A potentiostat based sensor was fabricated using fluorine doped tin oxide electrode (FTO) drop casted with gold nanoparticle (AuNPs) and immobilized with nCovid-19 monoclonal antibody (nCovid-19 Ab) to measure change in the electrical conductivity. Similarly, eCovSens was used to measure change in electrical conductivity by immobilizing nCovid-19 Ab on screen printed carbon electrode (SPCE). The performances of both sensors were recorded upon interaction of nCovid-19 Ab with its specific nCovid-19 Ag. Under optimum conditions, the FTO based immunosensor and proposed SPCE-based biosensor device displayed high sensitivity for early detection of nCovid-19 Ag, ranging from 1 fM to 1 µM. Our in-house developed eCovSens device can successfully detect nCovid-19 Ag at 10 fM concentration in standard buffer that is in close agreement with FTO/AuNPs sensor where AuNPs were used for the amplification of the electrical signal. The limit of detection (LOD) was found to be 90 fM with eCovSens and 120 fM with potentiostst in case of spiked saliva samples. The proposed portable point of care (PoC) eCovSens device can be used as an alternative diagnostic tool for the rapid (within 10-30 s) detection of nCovid-19 Ag traces directly in patient saliva samples that displayed high sensitivity, stability, and specificity.

Functionalized TiO2 Nanotube-Based Electrochemical Biosensor for Rapid Detection of SARS-CoV-2

“…Lahyquah et al [ 18 ] used an array of carbon electrodes modified with gold nanoparticles for the detection of MERS-CoV. Very recently, a biosensor using gold nanoparticle decorated FTO glass immobilized with nCovid-19 monoclonal antibody was reported for the detection of SARS-CoV-2 [ 22 ]. The functionality of the electrochemical biosensor can be further improved by nanostructuring the electrode as it increases the electrochemical reaction rate due to an increased electrode surface area to volume ratio, thereby increasing the electrode surface area to analyte fluid volume.…”

Gold Nanorod Assisted Enhanced Plasmonic Detection Scheme of COVID‐19 SARS‐CoV‐2 Spike Protein

“…had a LOD of 90 × 10 −15 m and it displayed high linearity in the range of 1 × 10 −15 m to 10 × 10 −6 m concentration of the virus. [ 26 ] Since no particular benchmark has been arrived regarding the LOD, we believe that by incorporating properly customized Au NRs the LOD can be lowered down by several orders of magnitude.…”

“…This testing scheme mainly utilizes the reactivity between specific antibodies developed by the human immune system in response to the presence of viral antigens. [ 21–30 ] Many researchers have come up with unique schemes for detecting the spike protein of the SARS‐CoV‐2 virus. Mahari et al.…”

“…used fluorine doped tin oxide electrode along with Au nanoparticles as a detection scheme. [ 26 ] Zhang et al. designed a graphene field effect transistor (FET) that was highly sensitive to the SARS‐CoV‐2 virus spike protein antibody–antigen interaction.…”

Biomedical Science to Tackle the COVID-19 Pandemic: Current Status and Future Perspectives

“…An electrochemical biosensor measuring the current as a function of the bound amount of SARS-CoV-2 antigen has been reported [ 225 ]. If the genome amplification is required, this might be easily achieved by coupling the loop-mediated isothermal amplification (LAMP) method to AuNP-based colorimetric biosensor for COVID-19 diagnosis [ 226 ].…”