Gold nanostructures modified carbon-based electrode enhanced with methylene blue for point-of-care COVID-19 tests using isothermal amplification

• Published in: Talanta (Oxford) Vol. 265; p. 124841
• Main Authors: Kim, Hyo Eun, Schuck, Ariadna, Park, Hyeonseek, Huh, Hee Jae, Kang, Minhee, Kim, Yong-Sang
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.12.2023; Published by Elsevier B.V
• Subjects: coronavirus; COVID-19; COVID-19 - diagnosis; DNA; Electrochemical sensing; Humans; Loop-mediated isothermal amplification; Methylene Blue; Nanostructures; Nucleic Acid Amplification Techniques - methods; Point-of-Care Systems; Point-of-Care Testing; RNA, Viral - analysis; SARS-CoV-2; SARS-CoV-2 - genetics; Sensitivity and Specificity; COVID-19; Loop-mediated isothermal amplification; coronavirus; Electrochemical sensing; SARS-CoV-2
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2023.124841

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) envelope (E) and RNA-dependent RNA polymerase (RdRP) genes were detected via electrochemical measurements using a screen-printed carbon electrode (SPCE) (3-electrode system) coupled with a battery-operated thin-film heater based on the loop-mediated isothermal amplification (LAMP) technique. The working electrodes of the SPCE sensor were decorated with synthesized gold nanostars (AuNSs) to obtain a large surface area and improve sensitivity. The LAMP assay was enhanced using a real-time amplification reaction system to detect the optimal target genes (E and RdRP) of SARS-CoV-2. The optimized LAMP assay was performed with diluted concentrations (from 0 to 109 copies) of the target DNA using 30 μM of methylene blue as a redox indicator. Target DNA amplification was conducted for 30 min at a constant temperature using a thin-film heater, and the final amplicon electrical signals were detected based on cyclic voltammetry curves. Our electrochemical LAMP analysis of SARS-CoV-2 clinical samples showed an excellent correlation with the Ct value of real-time reverse transcriptase-polymerase chain reaction, indicating successful validation of results. A linear relationship between the peak current response and the amplified DNA was observed for both genes. The AuNS-decorated SPCE sensor with the optimized LAMP primer enabled accurate analysis of both SARS-CoV-2-positive and -negative clinical samples. Therefore, the developed device is suitable for use as a point-of-care test DNA-based sensor for the diagnosis of SARS-CoV-2. [Display omitted] •E and RdRp genes of SARS-CoV-2 were detected using the LAMP technique.•Decorating SPCE sensors with gold nanostars (AuNSs) improved sensitivity.•LAMP was combined with real-time amplification system.•AuNS-decorated SPCE sensors accurately analyzed SARS-C0V-2 samples.