Ultra-sensitive detection of SARS-CoV-2 S1 protein by coupling rolling circle amplification with poly(N-isopropylacrylamide)-based sandwich-type assay

• Published in: Talanta (Oxford) Vol. 279; p. 126572
• Main Authors: Feng, Yu, Yi, Kebing, Gong, Feng, Zhang, Yaran, Shan, Xiaoyun, Ji, Xinghu, Zhou, Fuxiang, He, Zhike
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2024
• Subjects: Aptamer; Poly(N-isopropylacrylamide); Rolling circle amplification; SARS-CoV-2; SARS-CoV-2; Aptamer; Poly(N-isopropylacrylamide); Rolling circle amplification
• ISSN: 0039-9140; 1873-3573; 1873-3573
• DOI: 10.1016/j.talanta.2024.126572

In the past few years, the COVID-19 pandemic, caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) seriously threatens global public health security due to its high contagiousness. It remains of vital importance to develop a rapid and sensitive assay for SARS-CoV-2. In this work, we proposed a sandwich-type assay based on poly(N-isopropylacrylamide) (PNIPAM), allowing efficient detection of the SARS-CoV-2 S1 protein in the homogeneous solution. Firstly, a direct sandwich-type assay was established with a linear range of 0.2–2 μg/mL and a limit of detection (LOD) of 0.11 μg/mL, which could realize rapid detection in about 1 h. Furthermore, the sandwich-type assay coupled with rolling circle amplification (RCA) obtained an increase in sensitivity of 5.9 × 104 folds with a wide linear range of 0.01 − 100 ng/mL and a LOD of 1.88 pg/mL. The average recoveries in unpretreated saliva were 90 %–113.0 %, indicating the potential of the developed method for application in practical samples. Given the high selectivity and sensitivity of the developed method, it has a significant potential for rapid and early detection of SARS-CoV-2. [Display omitted] •PNIPAM ensured the homogeneous reaction, enhancing the reaction efficiency.•The sandwich complex could be separated by simple thermal precipitation.•The direct sandwich-type assay could realize rapid detection in about 1 h.•The sandwich assay coupled with RCA achieved a 5.9 × 104-fold sensitivity enhancement.