Sensitive Detection of SARS-CoV-2 Spike Protein Using an Aptamer Sandwich Assay-Based Electrochemical Biosensor

초록

The coronavirus pandemic has highlighted the urgent need for rapid, sensitive, and accurate diagnostic tests to detect SARS-CoV-2, which causes COVID-19 disease. One promising approach is the use of aptamers, which are synthetic single-stranded DNA or RNA molecules possessing the ability to bind to specific targets with high affinity and specificity. In this study, we developed an aptamer-based electrochemical biosensor to detect the SARS-CoV-2 spike protein, a viral antigen commonly utilized in diagnostic assays in a sandwich assay. To fabricate the electrochemical biosensor, a capture aptamer was immobilized onto a gold electrode. The target protein was introduced with a secondary aptamer-conjugated gold nanoparticle (AuNP) to enhance the electrical signals. AuNPs were prepared by utilizing L-ascorbic acid or hyaluronic acid and were functionalized with a secondary aptamer. The secondary aptamer-conjugated AuNPs were first characterized to identify their physicochemical properties. The biosensor exhibited exceptional sensitivity and specificity, with a detection limit of 0.42 pg/mL, and showed no cross-reactivity with other respiratory viruses. The aptamer-based biosensor, coupled with secondary aptamer-conjugated gold nanoparticles, has significant potential as a rapid, cost-effective, and highly sensitive diagnostic tool for COVID-19, as well as for the detection of other infectious agents.

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