I grew up in the 90s and early 2000’s watching TV shows like The Magic School Bus, and Osmosis Jones, and as a result, I would often daydream and fantasize about being able to shrink down to microscopic size and explore the inner workings of the human body. I would doodle and sketch little spaceship-like vehicles that could use robotic arms to grasps medicines and deliver them directly to cancer cells and envisioned swarms of robots that deployed like fighter jets to destroy bad bacteria and viruses that were infecting an area of the body. Now 25-years later, new research might help make parts of those fantasies come true.
A team of researchers at the University of California San Diego have developed a new micromotor that is capable of pushing individual cells around as well as other nano-sized particles. This new motor is powered by ultrasound and uses magnetics to steer. More importantly, it can push these microscopic particles around accurately in very crowded spaces such as blood vessels.
“These microswimmers provide a new way to manipulate single particles with precise control and in three dimensions, without having to do special sample preparation, labeling, surface modification,” said Joseph Wang, a professor of nanoengineering at the University of California San Diego.
The team announced their research in a paper published in the journal, Science Advances earlier this fall, and demonstrated how these tiny motors work by pushing around individual silica particles as well as HeLa cells in an aqueous media without interacting with any other particles that were closely sharing the same small space. The team demonstrated precise control of the motors by moving particles around to spell out letters and was able to use the motors to move cells in three dimensions by climbing tiered blocks and stairs.
“We have a lot of control over the motion, unlike a chemically fueled micromotor that relies on random motion to reach its target,” said Fernando Soto, a nanoengineering Ph.D. student at UC San Diego. “Also, ultrasound and magnets are biocompatible, making this micromotor system attractive for use in biological applications.”
“The micromotors are hollow, half capsule-shaped polymer structures coated with gold. They contain a small piece of magnetic nickel in their bodies, which allows them to be steered with magnets. The inner surface is chemically treated to repel water so that when it is submerged in water, an air bubble spontaneously forms inside the micromotor,” the team said in a press release. “This trapped bubble allows the micromotor to respond to ultrasound. When ultrasound waves hit, the bubble oscillates inside the micromotor, creating forces that propel its initial movement. To keep the micromotor moving, researchers apply an external magnetic field. By changing the direction of the magnetic field, researchers can steer the micromotor in different directions and alter its speed.”
Just like the cartoons of my youth, these little motors could deliver radioactive particles or chemotherapy drugs straight to cancer cells, or aid in delivering antibiotics directly to an infected area. One could even imagine a scenario where these micro-motors are equipped with microscopic knives and are deployed to physically destroy parasites nested deep within the brain that would otherwise be extremely hard to kill with drugs or invasive surgery. Imagine swallowing a pill that contains hundreds of tiny robots powered by these motors that then sail off to repair damage in the spinal column, joints, or even the brain. They could be used to manually remove plaque from the brain that is believed to cause memory loss and body functionality in the elderly. The possibilities are endless, and I for one and very excited to see this technology progress!