An electrochemical, fluorescent, and colorimetric triple-mode homogeneous biosensor for the simultaneous detection of influenza A, influenza B, and SARS-CoV-2

Influenza A, influenza B, and SARS-CoV-2 are prevalent during the influenza season, and their symptoms are very similar. To enhance symptomatic and precise treatment, there is an urgent need for multi-pathogen simultaneous detection technology to rapidly identify the three viruses. Therefore, a homogeneous nucleic acid detection system has been developed based on DNA -RNA hybridization. This system depends on the most crucial triplemode probe consisting of a common fluorophore and an electrochemically active group to produce electrochemical, fluorescent, and colorimetric signal responses. Based on the electrochemical signal, supplemented by fluorescent and colorimetric signals, it enables rapid and sensitive detection of influenza A, influenza B, and SARS-CoV-2, with a detection limit of 0.3 aM for synthetic DNA in 40 minutes, and a detection limit of 100 CFU/ mL for engineered bacteria. In simulated sample detection, the system enables accurate identification of samples from multiple sources, such as serum, saliva, and nasopharyngeal swab, with a wide sample applicability range. In addition, the system can be utilized in conjunction with a microfluidic chip and a portable electrochemical instrument to simultaneously detect three viruses in clinical samples, making it convenient for non-professionals in remote areas to obtain results in a short period of time. This work provides a simple and scalable research idea and solution for the simultaneous detection of pathogens.