Nanozyme‐Based Colorimetric SARS‐CoV‐2 Nucleic Acid Detection by Naked Eye

Abstract Fluorescence‐based PCR and other amplification methods have been used for SARS‐CoV‐2 diagnostics, however, it requires costly fluorescence detectors and probes limiting deploying large‐scale screening. Here, a cut‐price colorimetric method for SARS‐CoV‐2 RNA detection by iron manganese silicate nanozyme (IMSN) is established. IMSN catalyzes the oxidation of chromogenic substrates by its peroxidase (POD)‐like activity, which is effectively inhibited by pyrophosphate ions (PPi). Due to the large number of PPi generated by amplification processes, SARS‐CoV‐2 RNA can be detected by a colorimetric readout visible to the naked eye, with the detection limit of 240 copies mL −1 . This conceptually new method has been successfully applied to correctly distinguish positive and negative oropharyngeal swab samples of COVID‐19. Colorimetric assay provides a low‐cost and instrumental‐free solution for nucleic acid detection, which holds great potential for facilitating virus surveillance.