The biological cell is basically a miniature factory, which contains a large collection of dedicated protein machines. In a Review, Martin van den Heuvel and Cees Dekker look at recent progress in using some of these proteins to move, manipulate or power artificial, nanoscale devices.

A single living cell is capable of performing a number of tasks: it can create a full copy of itself in less than an hour, sense its environment and respond to it, change its shape, and obtain energy from photosynthesis or metabolism, using principles that are similar to those of solar cells or batteries. And all this functionality comes from a variety of proteins.

In this Review authors focus on catalytic proteins that have moving parts, particularly kinesin and myosin proteins, that show a clear resemblance to machines. They found rotary motors with shaft and bearings and liner motors that move along filament tracks in a step-by-step motion powered by chemical energy derived from ATP or electric forces of ions.

One example is the bacterial flagellar motor used by bacteria such as E. coli as propulsion mechanism by spinning a helical flagellum. This powerful rotary biomotor made from more than 20 different proteins and generates torques of more than 1,000 pN-nm at 100 revolutions per second.

Currently there are some demonstrations of a biomolecular-powered nanostructures. A prominent example is the construction of a ~1 μm nickel nanopropeller rotated by F1-ATPase motor powered with ATP[1].

Although the latest advances in biomolecular motors in nanotechnology showed that the researches can use motor proteins to drive nanoscale components and interface proteins selectively to different materials, the authors note that many are still only at the proof-of-principle stage. And we are yet to witness a functional and useful device made from the biomolecular motors.

Yes there are challenges such as protein denaturation that limits the lifetime to several days but the small size and force-exerting of motor proteins and the range of potential applications gives them unique advantages over current human-made motors.

Upon studying and using biomotors, we will gather a lot of knowledge that is of interest to biology, material science, and chemistry, and it is reasonable to expect spin-offs for medicine, sensors, electronics, or engineering. And thus exploring biomotors in technology will remain an interdisciplinary playground for many years to come.

References: “Motor Proteins at Work for Nanotechnology,” by M.G.L. van den Heuvel and C. Dekker at Delft University of Technology in Delft, Netherlands, DOI: 10.1126/science.1139570

1. R. K. Soonget al., Science 290, 1555 (2000)

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