Revealing Mechanisms in the Early Stages of Virus Infection by Single-Virus Tracking

Unraveling the mechanisms of viral infection is crucial for controlling viral transmission and treating viral diseases. Viral infection exhibits highly complex and dynamic processes, involving diverse infection routes, multistep infection procedures, intricate interactions with host cellular components, and even spatiotemporal changes in the hierarchical structure of viral particles. Many critical biological events, such as viral entry, trafficking, and replication, can occur within seconds to minutes. Conventional virology techniques predominantly provide static, averaged information, often failing to accurately capture the dynamic features of viral infection.The advent of dynamic imaging technologies has ushered in a new era for virology research. Among these, single-virus tracking (SVT) represents a revolutionary breakthrough, enabling real-time visualization of individual fluorescently labeled virions using fluorescence microscopy. By reconstructing and statistically analyzing biomolecular trajectories with high spatiotemporal resolution, this approach yields quantitative insights into their dynamic behavior. In contrast to conventional virological methods, SVT offers three key advantages: (1) precise localization of individual viral trajectories during infection, (2) dynamic monitoring of virus-host interactions, and (3) focusing on specific steps in the viral infection. This cutting-edge technique has already demonstrated remarkable success in elucidating the mechanisms of viral infection, providing an unprecedented perspective for understanding viral infection processes.In this Account, we focus on the key problems addressed by dynamic imaging technology, particularly its applications in virology, and discuss how it enables critical discoveries and the key mechanisms of viral infection revealed using this technology. Specifically, we provide an in-depth analysis of three pivotal biological processes during viral infection: (1) the molecular mechanisms of viral entry into host cells, (2) intracellular transport of viral particles, and (3) the dynamic processes of membrane fusion and genome release. Building upon previous research, we present, for the first time, a systematic and comprehensive dynamic landscape of the early stages of viral infection, as revealed by SVT. Through representative case studies, we highlight the remarkable analytical power and broad applicability of dynamic imaging techniques in deciphering molecular mechanisms of biological processes. Finally, we discuss future challenges and directions in this field, highlighting the critical role of interdisciplinary approaches. We envision that enhanced collaboration across physics, chemistry, and life sciences will accelerate SVT's innovative applications in biomedical research and inspire novel strategies for uncovering unexplored mechanisms.