https://phys.org/news/2018-11-technique-biology-nanoscale.html

At the basis of much of biology are cells and, at even smaller scales, cell-like bubbles that float around in liquid doing critically important jobs. So, for instance, neurons communicate in our brain through vesicles that carry information and chemicals from one neuron to the next. The HIV virus is another tiny vesicle. Over time, the vesicle carrying HIV changes and becomes stiffer, which indicates that the virus is becoming more infectious.

But studying the properties of these tiny and critically important cellular sacs that travel through organisms in fluids has been difficult, especially when researchers get to the smallest floaters that are 40-100 nanometers in size. To study biological processes at tiny scales, the researchers use atomic force microscopes, which require removing the vesicles from their natural floating homes. The process is expensive, cumbersome, and slow. Furthermore, by taking them out of their natural settings, the biological materials also don't necessarily exhibit their natural behavior, said Dutta.