Dual-light control of nanomachines that integrate motor and modulator subunits.

A current challenge in the field of artificial molecular machines is the synthesis and implementation of systems that can produce useful work when fuelled with a constant source of external energy. The first experimental achievements of this kind consisted of machines with continuous unidirectional rotations and translations that make use of 'Brownian ratchets' to bias random motions. An intrinsic limitation of such designs is that an inversion of directionality requires heavy chemical modifications in the structure of the actuating motor part.