Exosomes are small (30 – 100 nm) extracellular vesicles, or structures within a cell that contain liquid, that transfer biologically active molecules, such as proteins and ribonucleic acid (RNA), between cells. They hold great promise as a delivery mechanism for molecules used to treat a wide range of diseases. However, a lack of understanding about how exosomes are taken up by cells currently limits their therapeutic use.
Exosomes are difficult to image using conventional optical microscopy because of their small size. To overcome this, the NPL team used a custom-built super-resolution structured illumination microscopy (SIM) system to investigate the binding and trafficking of exosomes across cell membranes.