Tiny robots made out of carbon could be the next big thing | Folio

Tiny robots made out of carbon could be the next big thing

They're too small to see with the naked eye, but microrobots could someday have applications from targeting tumours to purifying water and detecting flaws in pipelines.

• April 18, 2024
• By Geoff McMaster

Mahdi Hamidi works on next-generation robots so small they can't be seen with the naked eye.

In explaining his research, the professor in the Department of Mechanical Engineering alludes to the 1966 science-fiction film Fantastic Voyage, about a submarine vessel and its crew shrunk to microscopic size so they can travel through a scientist's body to remove a blood clot from his brain.

The day may not be so far off, says Hamidi, when tiny robots or "actuators" will be capable of swimming through a person's bloodstream to attack a tumour, harmlessly self-destructing once they have completed their task.

"Imagine millions of these microrobots that can detect a chemical released from a tumour inside the brain - they find their way to that area, encapsulate the tumour and stop its growth."

Fully realizing that dream still requires further collaboration by teams of engineers and medical specialists to make materials biocompatible, but Hamidi is already part way there. In a recent study published in the prestigious journal Advanced Materials, he demonstrates that such actuators - the submarines, if you will - can be built with carbon nanotubes, each five nanometres or 10,000 times thinner than a human hair, laid on a silicon wafer.

The entire structure can be as small as five microns, or one-twentieth the width of a human hair. It's activated by an electric charge prompting it to move in a predetermined way, say bending or opening and closing, to fulfil a specific application.

"You can simply send an electric signal, for example, and an electrochemical reaction happens around the surface of the micro-actuator, resulting in swelling used to open and close its open end," says Hamidi.

While still in its preliminary stage, the same technology could be used to activate the micro-actuator to bend, and ultimately walk or swim, he says.

Beyond medical applications - where microrobots, for example, may one day be used non-invasively to conduct a colonoscopy, pelvic exam or blood test - Hamidi says other researchers are considering how they might be used for water purification, swimming through a body of water to scavenge for pollutants, or in the oil and gas industry to detect flaws in pipelines.

Hamidi is also exploring how to attach nano-scale computer chips to his actuators, and even working on minuscule batteries with just enough charge to get the job done on any given mission.

"If they had processors onboard, that would be a game changer," he says. "The microrobot could be connected to the internet, and you could perhaps change the program during its mission."

His playing field may be as small as it gets, but Hamidi is well aware that his true challenge is thinking big.

"These are things I'm always thinking about. I believe if I don't do it, I'm pretty sure somewhere in the world there are some very smart people who will do it."

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