A tool that uses light to manipulate matter inside living cells is being used to help scientists understand how proteins assemble into different liquid and gel-like solid states, a key to understanding many critical cellular operations. Marvels of complexity, cells host many thousands of simultaneous chemical reactions. Some reactions happen inside specialized compartments, called organelles. Certain organelles, however, lack any membrane to wall themselves off from the rest of the matter floating within cells. These membrane-less organelles somehow persist as self-contained structures amidst a cellular sea of water, proteins, nucleic acids, and other molecules. Scientists at Princeton University have developed a new tool -- dubbed “optoDroplet” -- that offers unprecedented access to manipulating and understanding the chemistry that allows membrane-less organelles to function. "This optoDroplet tool is starting to allow us to dissect the rules of physics and chemistry that govern the self-assembly of membrane-less organelles," said Clifford Brangwynne, Ph.D., an Assistant Professor of Chemical and Biological Engineering at Princeton and senior author of a paper published online in Cell on December 29, 2016. "The basic mechanisms underlying this process are very poorly understood, and if we get a handle on it, there might be a hope for developing interventions and treatments for devastating diseases connected with protein aggregation, such as ALS." The Cell article is titled “Spatiotemporal Control of Intracellular Phase Transitions Using Light-Activated optoDroplets.” Previous research has demonstrated that membrane-less organelles assemble within the cell by a process known as a phase transition: examples of familiar phase transitions include water vapor condensing into dew droplets or liquid water freezing into solid ice.Login Or Register To Read Full Story