ENGINEERINGNET.BE – The method that Dr Saskia Lindhoud of UTwente uses to separate molecules is inspired by biological systems. For example, cells are good at making sure the right molecules are in the right place to participate in biological processes.
One way cells do this is by making use of compartments. In the classical picture of the cell, these compartments are surrounded by a membrane and are called organelles. These organelles float in the cytosol, the cellular fluid.
But it seems more and more that this cytosol also consists of compartments, so-called membraneless organelles. They look like droplets and form through water-in-water phase separation.
One hypothesis is that these membraneless organelles ensure that the right molecules are in the right place at the right time. Lindhoud: “If we understand how membraneless organelles can separate so precisely, this offers possibilities for separations in chemical processes. Many membraneless organelles form through interactions between positively and negatively charged groups on proteins and RNA.”
In our lab we mimic this with positively and negatively charged polymers. A polymer is a long molecule made up of a long chain of equal parts called monomers. In our study, the monomers are either positively or negatively charged.
When you mix solutions of these positively and negatively charged polymers, drop-like structures are formed with similar properties to membraneless organelles. Like membraneless organelles, our model droplets can selectively take up a protein, in our case lysozyme, from a complex protein mixture.”
“The structure of this enzyme was not affected by the way it was separated. Lysozyme is still able to break down, so the enzyme remains active.”
“Such a separation process of molecules is useful for recovering and recycling chemical substances or drug residues from waste water,” says Lindhoud.
“But we are not there yet. We continue to puzzle on other questions that still exist in the research process of separating molecules. However, our findings are a good step in that direction.”
– .
