SARS-CoV-2 Aptasensors Based on Electrochemical Impedance Spectroscopy and Low-Cost Gold Electrode Substrates

Abstract

SARS-CoV-2 diagnostic practices broadly involve either quantitative polymerase chain reaction (qPCR)-based nucleic amplification of viral sequences or antigen-based tests such as lateral flow assays (LFAs). Reverse transcriptase-qPCR can detect viral RNA and is the gold standard for sensitivity. However, the technique is time-consuming and requires expensive laboratory infrastructure and trained staff. LFAs are lower in cost and near real time, and because they are antigen-based, they have the potential to provide a more accurate indication of a disease state. However, LFAs are reported to have low real-world sensitivity and in most cases are only qualitative. Here, an antigen-based electrochemical aptamer sensor is presented, which has the potential to address some of these shortfalls. An aptamer, raised to the SARS-CoV-2 spike protein, was immobilized on a low-cost gold-coated polyester substrate adapted from the blood glucose testing industry. Clinically relevant detection levels for SARS-CoV-2 are achieved in a simple, label-free measurement format using sample incubation times as short as 15 min on nasopharyngeal swab samples. This assay can readily be optimized for mass manufacture and is compatible with a low-cost meter.

A Review on Potential Electrochemical Point-of-Care Tests Targeting Pandemic Infectious Disease Detection: COVID-19 as a Reference

“…Using Optimer (optimized aptamers) ligands and mass-fabricated thin-film gold electrode (TFGE) sensors, Lasserre et al reported an impedimetric, low-cost, high-specificity mass testing platform for SARS-CoV-2 S1 protein detection in 15 min [102]. The SARS-CoV-2 S1 domain-specific DNA Optimer was synthesized from a pool of 10 14 sequences, while the TFGE was made using an inexpensive glucose test strip material (i.e., polyester substrate).…”

Progress in Electrochemical Biosensing of SARS-CoV-2 Virus for COVID-19 Management

“…Accordingly, the sensor could detect SP within 15 min with a LOD of 64 fM in COVID-19 patient's nasopharyngeal samples. Other works related to the use of antibodies, aptamers, ACE2, and MIPs as receptors for electrochemical detection of SARS-CoV-2 SP [80][81][82][83][84][85][86] and their analytical performances are summarized in Table 3.…”

Electrochemical biosensors for SARS-CoV-2 detection: Voltametric or impedimetric transduction?

“…Similarly to MIP-based sensors, also virus-imprinted sensors have been realized for detection of several viruses [58] , [59] , [60] . Hussein et al [61] constructed the first impedimetric nanosensor based on a screen-printed carbon electrode modified with carbon nanotubes/tungsten oxide (CNTs/WO 3 ) for imprinting the complete SARS-CoV-2 particles within the polymer to create virus complementary binding sites.…”