Time-varying stress response and deformation dynamics of topologically-active DNA solutions

Out-of-equilibrium materials that can autonomously alter their rheological and structural properties are at the forefront of active matter and materials engineering research. However, using the topological conversion of the material constituents as a route towards active restructuring and rheological state changes in materials remains underexplored. We recently demonstrated that in situ topological conversion of DNA via restriction enzymes can drive diverse time-varying rheological properties of entangled DNA solutions and composites that depend non-trivially on the lengthscale of the measurement. Yet how the stress response and material deformations propagate across these lengthscales, and how these dynamics depend on the rate of nonlinear straining remains elusive. Here, we use our recently established OpTiDDM (Optical Tweezers integrating Differential Dynamic Microscopy) methods to investigate the spatiotemporally varying rheology and deformation dynamics of topologically-active circular DNA solutions undergoing enzymatically driven linearization and fragmentation. We couple the nonlinear force response to the deformation dynamics and stress propagation field and show that these couplings depend non-trivially on the spatiotemporal scales of the measurements and the DNA concentration.