TwinDemic detection: A non-enzymatic signal amplification system for on-site detection of multiple respiratory viruses

The simultaneous occurrence of multiple respiratory viruses, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 [CoV]) and influenza A virus (IAV), presents a challenge for accurate diagnosis and treatment. To address this, we developed the TwinDemic Detection (TDD) system—an integrated point-of-care diagnostic platform that can simultaneously detect CoV and IAV using a multi-respiratory virus identification approach. The TDD system contains a transparent poly(methyl methacrylate) microfluidic chip with a hydrogel-based gene detection sensor and a handheld fluorescence reader. This system uses a fuel-stimulated DNA probe to detect viral RNA and amplify the fluorescence signal without the need for enzymatic or thermal controls. The system's performance was tested using 45 human nasopharyngeal samples; results revealed positive and negative predictive values of 93.3 % and 96.7 % for CoV, and 100 % and 96.7 % for IAV, respectively. This system enables the accurate and simultaneous detection of multiple respiratory viruses for public health surveillance and shows potential for use as a point-of-care molecular test to monitor a wider range of viruses in the future.