Recently, Nicholas Charles and researchers from Harvard published a study that used simulations of elastic fibers to probe their response to stretching and rotation applied simultaneously. The results shed light on how DNA, proteins, and other fibrous materials respond to forces and get their intricate shapes.
In my previous post on soft nanoparticles, you were introduced to polymer-based nanoparticles that could be used in biomedical applications, one of which is cancer therapy. These nanoparticles have a range of useful properties for cancer treatments, including their spherical shape and small size (~100 nm), both of which are similar to exosomes, small globules that are used in nature for transferring proteins between cells. Since cells naturally absorb exosomes, artificial particles with this size and shape should also be easy for cells to absorb, which means these particles could be used to deliver drugs into cells. While this idea sounds promising, it hasn’t worked out in practice -- when drug-loaded polymer-based nanoparticles were injected into a tumor, subsequent tests showed that less than 1% of the injected dose entered the cancer cells. Since these particles were the correct size and shape, why didn’t they get inside the target cells?
Granular rearrangement and the deformation of beams under load are two well understood, but very different systems. What happens when you put them together?
Cells use tiny capsules called vesicles to uptake nutrients, to dump waste, and to communicate. They astonishingly alter the mechanics and size of these capsules that are made of very thin layers with an incredible efficacy and speed. But what are the key parameters that govern the formation of these vesicles?