They Move! - Intracellular Motors

When one thinks of a motor, they often think of a car motor or perhaps an electric motor. Something big hulking machine that makes your car run or spins the beater of your KitchenAid™.  Something similar to this:

Boiling it down however, a motor is something that coverts some form of energy into mechanical energy, that is, movement. Simply, a motor is something that spins. When you remove the notion of a motor being a large electrically driven hunk of metal, all sorts of possibilities arise. Possibilities like tiny nano-sized motors that can go inside cells. Tiny motors, inside your body, inside your cells. And they look pretty cute (the video has no sound).

In collaboration with ESPCI Paris (a physics and chemistry engineering college), Tom Mallouk's research group has created tiny rods made of gold and ruthenium that can be manipulated both collaboratively (many rods together) and independently using ultrasonic waves (sound higher pitched than humans can hear) as propulsion and magnetic waves as steering. Even better, the power-density of the ultrasonics used with the rods is in line with that of medical imaging solutions we use today, so we know its safe. Previous versions of this budding technology were incompatible with biological systems as it used fuels that were hazardous to living cells. These new rods both work well within the cytoplasm of the cell and are nontoxic.

Light Microscope and Scanning Electron Microscope Images of the Nanometers 

Just seeing what these little rods can do gives you an idea of the wide range of applications for these new little critters. Take this video of a bunch of these rods working cooperatively to rotate a line of cells.

In one situation you could make the little rods go insane, blending the internals of the cell. If you were able to target cancer cells with these rods, you could absolutely obliterate the cells, killing the cancer.

On the complete other end of the spectrum, delicate control of the rods could help future scientists learn more about the internal workings of the cytoskeleton of the cell (the network of filaments and tubules that provide support and movement throughout the cell) by poking and prodding around in ways we never have been able to before. Delicate control could also diagnose and provide therapy for various diseases in a noninvasive fashion.

These little rods are not only 50 times thinner than a human hair; they're also 50 times more useful. The technology is still in the very preliminary stages, but progress is being made. Brain surgery in the future may consist of injecting these little rods into your body, having the rods be controlled to go up in your brain, fix whatever needs to be fixed, and then get peed out. That seems a lot better than getting your head cracked open. As long as they don't accidentally crank up the speed and blend your brain...  well that'd be awkward.

If you'd like to learn more about this subject, a PDF of one of his recent publications on the topic can be found here.