Development of a Fluorescent Immunochromatographic Assay Based on Quantum Dot-Functionalized Two-Dimensional Monolayer Ti 3 C 2 MXene Nanoprobes for the Simultaneous Detection of Influenza A Virus and SARS-CoV-2.

Accurate and rapid detection of the influenza A virus (FluA) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can effectively control their spread. We developed a colorimetric and fluorescent dual-functional two-channel immunochromatographic assay (ICA) biosensor to simultaneously detect the above-mentioned viruses. A unique two-dimensional Ti 3 C 2 -QD immunoprobe was established by adsorbing dense quantum dots (QDs) onto the light green monostromatic Ti 3 C 2 MXene surface, resulting in light green colorimetric and superior fluorescence signals and guaranteeing high sensitivity, stability, and excellent liquidity for ICA detection. Rapid visual screening for FluA and SARS-CoV-2 infections was applicable via a green colorimetric signal. Sensitive and quantitative detection of viruses in their early stages of infection was performed by using the fluorescence signal. Our proposed Ti 3 C 2 -QD-ICA biosensor can simultaneously detect 1 ng/mL or 2.4 pg/mL FluA and 1 ng/mL or 6.2 pg/mL SARS-CoV-2 via its colorimetric or fluorescence signals, respectively, with a short testing time (20 min), good reproducibility, specificity, and accuracy. In addition, this method demonstrated sensitivity higher than that of the conventional AuNP-based ICA method in throat swab samples. Hence, our proposed Ti 3 C 2 -QD-ICA method can be potentially applied for the rapid, ultrasensitive, and multiplex detection of respiratory viruses.