Chiral motion of a self-assembled active chain.

Chirality, or the breaking of left-right symmetry, is ubiquitous in biology and may arise from

the rotational motion of cells. However, the exact mechanism of how such spontaneous

chiral rotations arise is yet to be discovered. Here, we hypothesize that the chiral rotational

motion of chains of particles may arise if their propulsion is directed at an offset angle to the

chain axis. While motivated by migrating biological cells, our model may be realized in more

controlled settings such as molecular motor-propelled biofilaments, or synthetic, chemically

active colloids with electric or magnetic dipole interactions. We use Brownian dynamics

simulations to examine the motion of self-assembled chains of model chiral dipolar particles

for different motility values, offset angles, and chain bending stiffness. We show that

active, flexible chains with off-axis propulsion result in net rotation in the direction of the

offset. The rate of rotation increases with offset angle and self-propulsion. In future work, we

will build a theoretical model that shows how the torque causing the rotation arises from the

offset velocity and curvature of the chains.