Topologically Active Polymers

ongoing

"Synthetic and biological polymers are everywhere, they make up a wide range of materials, from every-day plastics to living cell. The study of how polymers behave in solution is a well-established research field that allows the informed design of commercial products, from plastics to rocket propellant. Most of the polymers used in everyday applications have a fixed structure that cannot be changed in time and this assumption lies at the heart of classic polymer physics. In this project, I propose to shift this paradigm by considering polymers whose architecture can be modified in time via topological operations that cut and glue the polymers' backbone at the expense of energy. Polymers undergoing these operations can dynamically and selectively alter their architecture or topology and I thus name them ""topologically active polymers"" (TAPs). This project is inspired by the facts that the DNA in every living entity is constantly topologically altered in time to fulfil a range of basic functions (e.g. cell division) and that DNA is increasingly employed as a building block for responsive and multifunctional materials. I propose to computationally design and explore generic systems of TAPs and then experimentally realise them as solutions of DNA functionalised by special classes of ATP-consuming proteins. These active complex fluids are expected to display unconventional behaviours intimately linked to the accessible space of topologies, their dynamic morphology and non-equilibrium kinetics. For instance, they are expected to selectively respond to the concentration of certain proteins, e.g. Topoisomerase, that are enriched in cancer cells. Given the fundamental importance of polymer science and the ubiquity of topology-altering proteins in vivo, this exciting bottom-up project will not only open a new area of fundamental research with potential far-reaching applications but will also shed new light into the workings of certain vitally important classes of proteins."