Topologically Active DNA with ATP-driven Ligation

DNA ligation is a vital biological process that consumes energy to repair double-strand DNA breaks by ATP-driven DNA end-joining reactions. While engineered ligase enzymes are now routinely used in cloning, their role as material actuators is elusive. Here, we design and investigate -via combined experimental and theoretical approaches- complex fluids made of DNA molecules that undergo ATP-driven ligation. Using a pulse field gel electrophoresis and (micro)rheology, we characterise the temporal evolution of the fluid’s elastic and viscous behaviours. Our findings are then rationalised by considering a modified Smoluchowski coagulation equation and coarse-grained living polymer simulations. Our work, inspired by the biology of DNA repair, offers a way to realise non-equilibrium “topologically active” complex fluids that can pave the way for responsive and adaptive materials.