Single Molecule Studies of Topologically Complex Polymers

Massachusetts Institute Of Technology, Cambridge MA

Investigators

Abstract

The majority of materials used in society are based on advances in the 20th century related to linear polymers. The next century will take advantage of materials which are composed of molecules with more complex geometries, such as rings or "knitted" collections of rings. Watching single molecules using advanced microscopes and cameras allows one to provide deep insights in the molecular origins of material properties and in turn design more functional materials. Therefore, the major aim of this project is to use DNA as a model system to study ring-like polymers and collections of ring polymers joined into a chainmail-like geometry. The project will also encompass significant educational activities, including developing demonstration materials and exercises to introduce young students to concepts of polymer topology, training students in advanced manufacturing techniques, and structured mentoring of under-represented students. Single molecule studies of linear DNA molecules have provided rich insights in the fields of polymer physics, soft matter, and rheology. There is an emerging interest in polymers with more complex topologies which can translate to new or enhanced material properties. This project will study the polymer dynamics and rheology of topologically complex polymers, combining single molecule DNA experiments with simulations and theory. The PI plans to first start with studies of single circular polymers and then move on to ring assemblies, namely catenated DNA ring net-works in kinetoplasts. The project has three specific objectives: (i) to understand the role of self-entanglement in ring polymers, (ii) to study the equilibrium dynamics of kinetoplasts in the con-text of a model two-dimensional polymer system, and (iii) to study the compression and stretching of kinetoplasts in microfluidic devices. An important feature of this work is to establish kinetoplasts as a two-dimensional polymer system for single molecule polymer rheology studies, akin to what has been done with great success for over two decades with linear DNA. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.