Leigh is part of a growing band of molecular architects who have been inspired to emulate the machine-like biological molecules found in living cells – kinesin proteins that stride along the cell’s microscopic scaffolding, or the ribosome that constructs proteins by reading genetic code.
Over the past 25 years, these researchers have devised an impressive array of switches, ratchets, motors, rods, rings, propellers and more – molecular mechanisms that can be plugged together as if they were nanoscale Lego pieces.
Similar molecular switches could one day be used in sensors that respond to heat, light or specific chemicals, or that open the hatch of a nanoscale container to deliver a cargo of drug molecules at precisely the right time and to exactly the correct place in a person’s body.
Stoddart’s switches displayed two properties that would come up again and again in the molecular machines that followed. In 1999, after early experiments with shuttles and switches, the field took a big step forward with the creation of the first synthetic molecular motor8.
Over the past few years, detailed chemical studies and molecular dynamics simulations have shown that this ‘Brownian ratchet’ concept underlies all chemically driven molecular machines, including many biological motors.
Coating a micromotor with light-responsive molecular switches could offer extra control over its movement, he suggests.