In Situ Monitoring of the Movement of a Single Nanovesicle: Toward Elucidating Their Biological Activities in Human Cells

The field of vigorous nanomedicine offers significant possibilities for effective therapeutics of various diseases, and advanced nanovesicles (NVs), represented by artificial liposomes, natural extracellular vesicles, and hybrid cell membrane coating nanoparticles, especially show great potential due to their diverse biological activities. Due to the small size and complex composition of NVs, however, most studies have relied on traditional biochemical analysis of bulk NVs, which are separated from biofluids or synthesized in the laboratory. Although informative, the in situ and dynamic interactions between NVs and human cells are not captured and monitored, which hinders the understanding of the spatiotemporal behaviors and pathological characterizations of single NVs. Inspired by single-particle tracking technology, a powerful tool for elucidating the dynamics of diverse, complex, and heterogeneous systems, and combined with recent advances in innovative NVs labeling strategies and high-spatiotemporal-resolution microscopy techniques, the biological activities of NVs in human cells at the single-vesicle level can be developed and elucidated. Here, the latest advances and challenges in single-NVs analysis, identifying urgent and outstanding questions in the quest to unravel the biology of NVs and their therapeutic applications, are reviewed.