Active Flow-Driven DNA Remodeling Generates Millimeter-Scale Mechanical Oscillations, Enabling Self-Morphing Materials

DNA constantly reshapes itself within living cells, a process vital for controlling genes and organising structures, but the underlying physical mechanisms remain unclear. Maya Levanon, Noa S. Goldberg, and colleagues at the Weizmann Institute of Science and Technion, Israel Institute of Technology, now demonstrate that rhythmic DNA reorganization can arise purely from mechanical forces. The team created a system combining DNA with microscopic filaments and molecular motors, revealing that the resulting active flows stretch and tangle the DNA, generating large-scale, coordinated oscillations spanning millimetres. This discovery establishes a fundamental physical route to self-organised motion in materials and offers new principles for designing soft robotic systems capable of autonomous movement and reshaping without relying on complex chemical signalling.

DNA Networks Control Microtubule Gel Mechanics

Scientists investigated how DNA networks influence the mechanical properties and organization of active gels composed of microtubules and motor proteins. The research focused on understanding how DNA length and concentration affect the gel’s flow, the formation of swirling patterns, and overall stability. Using fluorescence microscopy, the team tracked particle and DNA network movement within the active gel, revealing how gel behavior is influenced by DNA concentration and length. Higher DNA concentrations create denser networks, while shorter DNA lengths result in finer mesh sizes. The active gel exhibits complex flow patterns, including large-scale vortices, with the size and dynamics of these vortices influenced by the DNA network.

Analysis of the flow revealed a distribution of energy across different length scales, indicating turbulent-like fluctuations, and the system exhibits both stable and oscillating instabilities depending on parameters like DNA concentration, length, and gel elasticity. Researchers emphasized the importance of distinct length scales, the size of the DNA network, the channel width, and a larger scale associated with the overall gel structure, for understanding the system’s behavior. This research provides valuable insights into the mechanics of biological systems, such as the cytoskeleton, and for designing new materials with tunable properties.

Active Matter Drives Rhythmic DNA Organisation

Scientists demonstrated rhythmic reorganization of DNA within an active material composed of microtubules, kinesin motors, and DNA, creating a self-morphing system. The team engineered a fluid containing microtubules and kinesin motors, inducing bundling with a chemical additive and generating turbulent-like active flows with steady velocities. Long, linear double-stranded DNA, concatenated to approximately 40 micrometers, was introduced, behaving as a flexible polymer with an elastic response. Initially, the active flows stretched and entangled the DNA, promoting the formation of a mesoscopic network that progressively coarsened over time.

Fluorescent labeling revealed a transition from a homogeneous solution to a well-defined network of coarse filaments, distinct from passive DNA solutions. As the network developed, the active fluid shifted from turbulent-like flow to sample-wide, temporally coherent positional oscillations, with tracer particles displaying oscillating displacements reaching 0. 25 millimeters in amplitude. Particle image velocimetry confirmed the growth of coherent rotating domains, increasing in velocity magnitude and periodically reversing direction. This dynamic feedback transformed the composite from a disordered fluid to an active viscoelastic gel, driving coherent, system-scale oscillations and demonstrating a novel route to autonomous material reshaping.

DNA Entanglement Drives Millimeter-Scale Oscillations

This work demonstrates a novel route to rhythmic DNA reorganization, achieving autonomous, system-spanning oscillations within a minimal active composite material. Scientists embedded DNA within an active fluid of microtubules and kinesin motors, creating a self-morphing material where active flows stretch and entangle the DNA. This process spontaneously forms a self-organized viscoelastic network, driving a transition from disordered flow to synchronized, millimeter-scale oscillations with vortices. Initially, the active fluid mixed and stretched the DNA, promoting entanglement and ultimately forming a mesoscopic network.

Fluorescent labeling revealed a transition from a homogeneous solution to a well-defined network of coarse filaments, distinct from passive DNA solutions or fluids lacking microtubules. As the network coarsened, the active fluid shifted from turbulent-like flow to sample-wide, temporally coherent positional oscillations, with tracer particles displaying oscillating displacements growing to 0. 25mm. Particle image velocimetry confirmed the growth of coherent rotating domains, expanding from local patches to 2mm-scale vortices with increasing velocity magnitude. The velocity-velocity correlation length, initially at ~250μm, sharply increased by an order of magnitude to a maximum of 1.

5mm, approaching the channel width, before saturating. This increase tracked DNA-network coarsening, as measured by a growing fluorescence-intensity coefficient of variance. These findings establish a minimal physical route to self-morphing soft materials capable of sustaining system-spanning oscillations in three dimensions.