A nanozyme-catalyzed nasopharyngeal swab sensor for ultra-fast colorimetric detection and highly sensitive Raman spectroscopic qualitative analysis of influenza virus.

Rapid and sensitive detection of pathogenic viruses is essential for controlling pandemics. In this study, the bimetallic metal-organic framework (MOFs) with enhanced peroxidase (POD)-like activity, termed as MIL-101(CoFe), was developed for ultra-fast colorimetric detection and highly sensitive quantitative Raman assay of influenza viruses in nasopharyngeal swab specimens. The synergistic effect between Fe and Co in MIL-101(CoFe) significantly enhanced the POD-like activity, enabling efficient catalysis of the substrate TMB in the presence of H2O2 to produce blue oxidized TMB (ox-TMB), which has a characteristic Raman peak at 1609 cm-1. By modifying the surface of MIL-101(CoFe), with influenza virus antibodies (Anti-FluB-MmAb), the sensor can specifically bind to the viruses on the surface of nasopharyngeal swabs. Consequently, the presence of influenza virus on nasopharyngeal swabs can be rapidly, visibly, and accurately identified by colorimetry, while the intensity of the ox-TMB characteristic peak allows for quantitative Raman spectroscopic analysis of the virus, with a detection limit as low as 1.3 ng/mL within 5 min.