Establishment of a Raman microsphere-based immunochromatographic method for the combined detection of influenza A and B viruses and SARS-CoV-2 antigen on a single T-line

A simple and rapid method based on Raman microsphere immunochromatography was developed in this study for the simultaneous detection of influenza A and B viruses and SARS-CoV-2 on a single test T-line. Three types of Raman microspheres with different Raman characteristics were used as the signal sources and were labelled with monoclonal antibodies against FluA, FluB and SARS-CoV-2, respectively. A mixture of antibodies containing anti-FluA monoclonal antibody, anti-FluB monoclonal antibody and anti-SARS-CoV-2 was sprayed on the detection line (T), and goat polyclonal antibody to chicken (IgY) encapsulated on the quality control line (C), for qualitative detection of these three viruses by the double antibody sandwich method. The results demonstrated that the LOD values were 0.5 ng mL^-1 for FluA, 0.25 ng mL^-1 for FluB, and 0.5 ng mL^-1 for SARS-CoV-2. The method showed good repeatability for the respiratory viral antigens, with CV values below 15%. Oxymetazoline and commonly used oral medications did not interfere with the test results; the strips did not cross-react with common respiratory virus antigens, demonstrating good specificity. This method does not require any complicated pre-treatment, and all three viruses can be detected simultaneously by titrating one sample, which improves the detection efficiency. The Respiratory Pathogen Multiplex provides a scientific basis for preventing and controlling the spread of respiratory diseases by analyzing data to understand epidemiological trends and the spread of pathogens.