Microrobots prove successful in mouse cancer treatment, scientists eye human trials

Engineers have found a way to send tiny bubble-like spheres to deliver drugs within the body with high precision.

A team of scientists at the California Institute of Technology (Caltech) has developed microrobots that can swim through various bodily fluids, navigate themselves to specific targets in the body, unload therapeutic drugs, and dissolve without causing any damage to health.

"Rather than putting a drug into the body and letting it diffuse everywhere, now we can guide our microrobots directly to a tumor site and release the drug in a controlled and efficient way," said Wei Gao, professor of medical engineering at Caltech and the author of the study.

While nanorobots are not new in the field of robotics, applying robots to the human body has so far been challenging due to the presence of biofluids such as blood, urine, or saliva that could damage the bot. Also, the microrobots that enter the body need to be compatible with the biological organism.

The Caltech team’s discovery is groundbreaking because of the bots' structure. These microrobots are spherical structures made of hydrogel, a jelly-like material used for contact lenses that can trap large amounts of fluid.

Caltech’s scientists created a unique robot structure, enabling the outer sphere to carry the therapeutic cargo to a target site within the body.

Magnetic nanoparticles present in the tiny bot allow scientists to direct them to a desired location within a body using an external magnetic field. When the robots reach their desired place, they stay there while the drug passively diffuses out.

To enable movement, the team designed the microrobot with two openings: one on top and one on the side. When exposed to ultrasound, bubbles vibrate and push fluid out through the openings, propelling the robots forward.

Each microstructure contains an egg-shaped bubble that acts as a highly effective ultrasound contrast agent, allowing real-time monitoring of the bots inside the body.

The little gadgets have already demonstrated high precision in mice, successfully delivering drugs that reduced the size of bladder tumors. Scientists are hoping to test the newly developed technology with humans.

"We think this is a very promising platform for drug delivery and precision surgery. Looking to the future, we could evaluate using this robot as a platform to deliver different types of therapeutic payloads or agents for different conditions. And in the long term, we hope to test this in humans," said Gao.