Flow Cytometric Analysis of Nanoscale Biological Particles and Organelles

Analysis of nanoscale biological particles and organelles (BPOs) at the single-particle level is fundamental to the in-depth study of biosciences. Flow cytometry is a versatile technique that has been well-established for the analysis of eukaryotic cells, yet conventional flow cytometry can hardly meet the sensitivity requirement for nanoscale BPOs. Recent advances in high-sensitivity flow cytometry have made it possible to conduct precise, sensitive, and specific analyses of nanoscale BPOs, with exceptional benefits for bacteria, mitochondria, viruses, and extracellular vesicles (EVs). In this article, we discuss the significance, challenges, and efforts toward sensitivity enhancement, followed by the introduction of flow cytometric analysis of nanoscale BPOs. With the development of the nano-flow cytometer that can detect single viruses and EVs as small as 27 nm and 40 nm, respectively, more exciting applications in nanoscale BPO analysis can be envisioned.