Conformation and dynamics of wet externally actuated filaments with tangential active forces.

Abstract

We explore the impact of hydrodynamic interactions on the conformational and dynamical properties of externally driven active polymers with tangential forces using multiparticle collision dynamics simulations. This model applies to non-force-neutral motile polymers, such as biofilaments in motility assays with substrate-fixed molecular motors or colloidal chains driven externally by forces tangential to the backbone exerted through dynamic tweezing. By analyzing active filaments with varying degrees of flexibility, we find that fluid-mediated interactions significantly influence both their conformation and dynamics. These interactions cause polymer conformations to shrink relative to their dry counterparts, especially for semiflexible polymers at high activity levels, where the average size of wet chains becomes nearly three times smaller, due to local buckling of wet polymers. This hydrodynamic-induced shrinkage is a hallmark of active polymers, as fluid-mediated interactions do not affect conformational properties of passive polymers. Furthermore, for tangentially driven polymers where activity and conformation are coupled, hydrodynamic interactions significantly enhance the orientational and translational dynamics compared to their dry counterparts.