Nondestructive tracking of viral infections by viral protein-initiated fluorescent sensors

Real-time tracking of viral infection processes is critical for elucidating the pathogenic mechanisms and therapeutic targets. A more detailed understanding of viral movement in the extracellular environment <i>in vivo</i> as well as in extraplasmic space requires the development of a tool capable of stable fluorescence without affecting the virus's own physiological chemotaxis. Herein, we report a viral protein-based enhanced targeting (PBET) fluorescent sensor that can image the infection process of live viruses in spaces adjacent to living cells and <i>in vivo</i> environments. Experimental and computational studies have shown that PBET sensors are capable of spontaneous dimer formation and have an enhanced ability to target the electrostatic interactions of functionalized motifs through the restriction of intramolecular motions. The PBET sensor effectively ensured that the attachment process did not affect the physicochemical properties of the virus because of the molecularly induced targeting buffer effect (MITB) binding to the viral surface proteins. Meanwhile, fluorescence intensity, persistence, and minimum labeling concentration, all several times higher than existing fluorescent dyes, ensure that this sensor element can stably and efficiently track viral particle infection timelines at the cellular and tissue levels. This provides a novel platform strategy for antiviral localization studies and the diagnosis of infected areas in patients.IMPORTANCEReal-time viral tracer technology plays a driving role in deconstructing viral infections by demonstrating the infection process and the potential binding regions in multiple dimensions. However, the methods of labeling viruses are still limited to traditional fluorescent protein labeling and loaded fluorescent molecules. These schemes have undoubtedly had a noticeable impact on simple viral structures, with labeled viruses showing fluctuations in infectivity. Therefore, it is important to nondestructively perform the dynamic tracing of viruses. By integrating the existing protein fluorescent labeling schemes and fluorescent molecular charge transfer theory, this study builds a system with nondestructive labeling, dynamic tracing, and labeling mechanism analysis of viruses, which is of great scientific value in the prevention of infectious diseases.