  In macroscopic mechanical devices torque is transmitted through gearwheels
and clutches. In the construction of devices at the nanoscale, torque and its
transmission through soft materials will be a key component. However, this
regime is dominated by thermal fluctuations leading to dissipation. Here we
demonstrate the principle of torque transmission for a disc-like colloidal
assembly exhibiting clutch-like behaviour, driven by $27$ particles in optical
traps. These are translated on a circular path to form a rotating boundary that
transmits torque to additional particles confined to the interior. We
investigate this transmission and find that it is determined by solid-like or
fluid-like behaviour of the device and a stick-slip mechanism reminiscent of
macroscopic gearwheels slipping. The transmission behaviour is predominantly
governed by the rotation rate of the boundary and the density of the confined
system. We determine the efficiency of our device and thus optimise conditions
to maximise power output.
