A Dual-Response Quantum Dot Biosensor for Viral Protease and Nucleic Acid Detection.

The ongoing circulation of SARS-CoV-2 and seasonal influenza viruses poses significant diagnostic challenges due to overlapping clinical symptoms and the risk of coinfections. Current detection methods, such as RT-qPCR and immunoassays, face limitations, including time-consuming protocols, the inability to differentiate viable viruses, and poor suitability for in vivo imaging. To address this, we developed a quantum dot-based Förster resonance energy transfer (FRET) biosensor (QDB) for the simultaneous detection of SARS-CoV-2 and influenza viruses. The biosensor exploits the specific cleavage of the SARS-CoV-2 main protease and the recognition of influenza viral RNA to produce distinct fluorescence signals. The dual-response biosensor offers rapid response, high specificity, membrane permeability, and biocompatible detection, supporting both in vitro detection and potential in vivo imaging. By modifying the recognition elements, this platform is readily adaptable for multiplexed detection of diverse pathogens, offering significant potential for clinical diagnostics and therapeutic guidance.