Microtubule-based active fluids with improved lifetime, temporal stability and miscibility with passive soft materials

We have developed several distinct model systems of microtubule-based 3D active isotropic fluids and have compared their dynamical and structural properties. The non-equilibrium dynamics of these fluids is powered by three different types of kinesin motors: a processive motor, a non-processive motor, and a motor which is permanently linked to a microtubule backbone. The fourth modification uses specific microtubule crosslinkers to induce bundle formation instead of a non-specific depletant. In comparison to the formerly developed systems, each new active fluid formulation has certain enhanced properties. Firstly, linking motors to the microtubule backbone enhances the fluid lifetime from hours to several days. Furthermore, switching to the non-processive motors significantly increases the temporal stability of the active dynamics, while using specific cross-linkers yields systems that can incorporate other passive soft materials, such as, polymer gels or liquid crystals. These novel developed model systems will significantly aid and improve our ability to quantify diverse phenomena observed in microtubule based active matter.