Target-triggered cascade signal amplification for sensitive electrochemical detection of SARS-CoV-2 with clinical application

• Main Authors: Deng, Y. (Author), Li, G. (Author), Li, J. (Author), Peng, Y. (Author), Wang, L. (Author), Wang, M. (Author), Xiang, L. (Author), Yang, J. (Author), Zhou, T. (Author)
• Format: Article
• Language: English
• Published: Elsevier B.V. 2022
• Subjects: Ammonia; Amplification; Biosensors; Cascade signal amplification; Chemical detection; Clinical application; Coronavirus; Coronaviruses; COVID-19; Diagnosis; DNA; Electrochemical biosensor; ELectrochemical detection; Global health; RNA; SARS; SARS-CoV-2 RNA; Severe acute respiratory syndrome coronavirus; Severe acute respiratory syndrome coronavirus 2 RNA; Signal amplifications
• Online Access: View Fulltext in Publisher

 The spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to the outbreak of the 2019 coronavirus (COVID-19) disease, which greatly challenges the global economy and health. Simple and sensitive diagnosis of COVID-19 at the early stage is important to prevent the spread of pandemics. Herein, we have proposed a target-triggered cascade signal amplification in this work for sensitive analysis of SARS-CoV-2 RNA. Specifically, the presence of SARS-CoV-2 RNA can trigger the catalytic hairpin assembly to generate plenty of DNA duplexes with free 3′-OH termini, which can be recognized and catalyzed by the terminal deoxynucleotidyl transferase (TdT) to generate long strand DNA. The prolonged DNA can absorb substantial Ru(NH3)6 3+ molecules via electrostatic interaction and produce an enhanced current response. The incorporation of catalytic hairpin assembly and TdT-mediated polymerization effectively lowers the detection limit to 45 fM, with a wide linear range from 0.1 pM to 3000 pM. Moreover, the proposed strategy possesses excellent selectivity to distinguish target RNA with single-base mismatched, three-base mismatched, and random sequences. Notably, the proposed electrochemical biosensor can be applied to analyze targets in complex circumstances containing 10% saliva, which implies its high stability and anti-interference. Moreover, the proposed strategy has been successfully applied to SARS CoV-2 RNA detection in clinical samples and may have the potential to be cultivated as an effective tool for COVID-19 diagnosis. © 2022 Elsevier B.V.