These tiny robots could help treat cancer: study

Robots are good for a lot of things: shopping, emotional support, and even insane viral internet challenges.

Scientists are hoping soon that they will also be used to fight cancer – by deploying microscopic robots through our bodies to attack tumors.

"The microrobot concept is really great because you can get micromachines exactly where you need them," says Lihong Wang, a researcher at Caltech's Division of Engineering and Applied Science. He and his partner Wei Gao develop robots that can treat hard-to-reach body parts, especially the digestive tract. According to Wang, the technology could be used for targeted drug delivery or even "microsurgery".

The microbots are made of magnesium and, with the exception of a small, unprotected part, covered with a gold polymer and a parylene polymer that would withstand the digestive enzymes of the stomach. The uncoated area exposes the metal to digestive fluids, which react with magnesium to create tiny bubbles. Scientists say that these bubbles act as a kind of helix for microbeads.

To make the bots clinically useful, Wang and Gao applied a layer of medicine between the metal ball and the polymer layer. For added protection in the harsh environment of the gut, the entire bot is wrapped in paraffin wax.

But the most amazing part of this method is the way they tell microbots where to go. For this, Wang uses a technique that he developed called computerized photoacoustic tomography (PACT).

Infrared laser light pbades through tissues to reach red blood cells, causing the vibration of oxygen-rich hemoglobin molecules. Sensors close to the skin detect the vibrations and badyze the data to create an internal image of the microbot environment, including tumors nearby.

When scientists see their microbots – which appear clearly on the PACT images – near the tumor, they use a high-power near-infrared laser to help them move them forward. The metallic sphere absorbs the light that melts the wax, exposing the uncoated area of ​​the robot and propelling it with bubbles as close as possible to the intended target.

"These micromotors can enter the mucus of the digestive tract and stay there for a long time. It improves the delivery of drugs, "says Gao. "But because they're made of magnesium, they're biocompatible and biodegradable."

Successful animal tests have encouraged Gao and Wang, whose work was published this week in Science Robotics, to advance their research and possibly treat other parts of the human body.

"We have demonstrated the concept that you can reach the diseased area and activate microbots," says Gao. "The next step is to evaluate their therapeutic effect."