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.

Recent advances in point-of-care testing of COVID-19

“…Conversely, fluorescence-based methods offer highly sensitive detection and quantification, even at trace analyte levels. This capability is exemplified by the combination of fluorescence and combined with colorimetric techniques, 171 as well as nanoplasmonic amplified impedance measurements 172 combined with colorimetric pathogen detection, have also shown enhanced limits of detection, swift sample-to-response turnaround times, and quantifiable colorimetric signals in human saliva. Additional representative schematics of colorimetric and fluorescence methods for COVID-19 diagnosis are presented in Fig.…”

Signal Amplification Strategy Design in Nanozyme‐Based Biosensors for Highly Sensitive Detection of Trace Biomarkers

“…Test strips allow for the rapid acquisition of qualitative or quantitative results through visual or instrumental observation of the chromogenic reaction occurring on the accumulated complex on the Tline. [73] However, with the vigorous development of other assays Co-Histidine -graphene quantum dots (GQD)-G OXD Chlorpyrifos (0.57 ng mL −1 ) [110] two-dimensional (2D) covalent organic frameworks OXD UO 2 2+ (50×10 −9 m) [111] Globotriose@Au@Fe-TFPA-COP POD Shiga toxins (7 ng mL −1 ) [112] Bi 2 Fe 4 O 9 POD DA (51 nm) [113] Hemin-GE oxide POD CEA (0.05 ng mL −1 ) Ebola (10 pm) [114] Enhancing the catalytic activity of nanozyme signal probes for amplified colorimetric signals via doping modulation strategy Fe@PDA POD L.monocytogenes (2.3 CFU mL −1 ) [115] Single-atom Fe / nitrogen-doped graphene (SA-Fe/NG) POD Cr(VI) (3 nm) [116] ZnBNC SAzymes POD P-phenylenediamine (0.1 μm) [117] Cu-Pt POD Glucose (12.5 mm) [36] Fe-SAzymes POD Galactose (10 mm) [118] DNA /Fe-SAzymes POD Cancer cells (100 cells) [119] FeN/C SAzymes OXD Pesticides (1 nm) [120] Zr-based MOF POD Phosphorylated proteins (0.16 mg mL −1 ) [121] Iron manganese silicate nanozyme POD SARS-CoV-2 (240 copies mL −1 ) [122] Fe-N/S-C OXD GSH (3.92 μm) Hg 2+ (0.17 nm) [35] Cu-Salt-Fe POD Cholesterol (2.73 μm) [123] UIO-66 MOFs POD Hela cells (481 cells mL −1 ) [124] (e.g., ELISA, high-performance liquid chromatography (HPLC), PCR), the advantages of test strips have gradually diminished.…”

Bifunctional Mo2N Nanoparticles with Nanozyme and SERS Activity: A Versatile Platform for Sensitive Detection of Biomarkers in Serum Samples

“…As newly emerging artificial enzymes, nanozymes ingeniously link nanomaterials with enzymology, which have captured extensive interest in food safety, environmental monitoring, and disease diagnosis owing to their significant characteristics of lower cost, higher stability, as well as persistent catalytic efficiency compared with natural enzymes. − It is universally acknowledged that the research on nanozymes for analytical purposes mainly involves the signal visualization of enzyme substrates after catalytic reaction. However, the assay is limited due to the low sensitivity and color interference caused by nanozymes themselves and the sample matrix. , To achieve high sensitivity and accuracy of detection, several technologies have been adopted in the research based on a nanozyme-mediated catalytic platform.…”