You may be wondering: Could someone’s implanted micromachine be triggered accidentally by an external magnet or by a malicious person with fiendish magnetic powers? In other words, is the X-Men’s
Magneto a risk factor? “Somebody walking by with a magnet won’t trigger it, but there are some cases where it’s not ideal,” Sia says. His lab is working on other ways to wirelessly drive the mechanism, including an
ultrasound technique.
The hardest part of the design process was getting the material right, Sia says. Very flexible and soft materials are compatible with the body’s soft innards, unlike rigid silicon or metal devices. “But if your material is collapsing like jello, it’s hard to make robots out of it,” he says. “It has to be stiff enough to work like a tiny implantable machine.”
The pieces of the Geneva device were each printed in soft hydrogel.
The next step was in vivo. Sia’s team wanted to see if their devices would work inside the body, with all the complications of chemistry and anatomy. Some mice with bone cancer received implanted devices that were loaded up with a chemo drug; other mice received typical chemotherapy, which floods the whole body with a toxic drug. When the team compared the effects of the device’s localized and periodic delivery of the drug to those of the typical treatment, the results were impressive. The bionic mice’s tumors grew slower, more tumor cells died off, and fewer cells elsewhere in the body suffered peripheral damage.
Fluorescent imaging shows a chemo-delivering device inside a lab mouse.
The clinical possibilities seem obvious—oncologists could deliver more targeted and concentrated doses of powerful chemo drugs, and Sia imagines other uses, like regulating the release of hormones. But the drug delivery device is really just a proof of concept, he says. He’s not rushing out to form a startup: “We have to do the cost-benefit analysis to see if this is really a commercializable device,” he says.
He is bullish, however, on the medical potential of tiny squishy robots in general. Soft and mobile little bots could one day act as internal repair crews, doing a doctor’s work from the inside. (For more on this, check out
IEEE Spectrum’s article on
medical microbots.) Sia says his fabrication platform is capable of turning out a wide variety of devices. “I’m confident that we’ll find something useful,” he says.
Sia won’t say exactly what types of devices his lab is now experimenting with, except to say that they’re looking at implanted devices that move. Here’s my guess: It’s a tiny squishy micromachine that resembles a cuckoo clock.