Researchers at the Massachusetts Institute of Technology (MIT) have found a way to combine utrathin electronics with miniature particles, moving a step closer to creating microscopic machines, or tiny floating robots, that could be used to probe the human gut for disease, search the environment for pollutants and other tasks.
The devices — referred to as aerosolizable electronic devices— could be cheaper or easier to deploy for some tasks than drones, satellites or sensors.
The researchers will present their work today at the 255th National Meeting & Exposition of the American Chemical Society (ACS) in New Orleans. Theirs will be one of more than 13,000 presentations on a wide range of science topics.
“You can make electronic circuits that are a single atom thick, which is just insanely thin,” Michael Strano, Ph.D., says. “One creative use no one has thought of until now is taking these electronics and grafting them onto a colloidal particle. The particle, which can float in the air like a speck of dust, has simple computing functions. You can bring these new electronics to environments they otherwise could not access.”
As a first step, the researchers needed to develop a compatible set of electronic components for the particle’s coating to form a closed autonomous circuit. “This was difficult to do,” says Volodymyr Koman, Ph.D., a research fellow in Strano’s group at MIT. “We went through a number of different devices to meet certain power and energy requirements.”
In the end, Strano’s team selected a biocompatible material called SU-8 for the micrometer-sized particles and etched them to create a closed circuit consisting of a power source, a detector and a memory device.
The researchers then checked whether and how far the electronic particles could travel. They aerosolized them and propelled them toward a target; the tiny particles flew a couple of feet.
The researchers envision a range of uses for these miniature flying machines. Monitoring large areas for bacteria, spores, smoke, dust or toxic fumes currently requires enormous resources, Koman says. Satellites or a fleet of flying drones can do these tasks but they are expensive, while on-the-ground sensors require labor-intensive installation, which is often slow in comparison to the aerosol spreading velocity.
“As an alternative, we introduce the concept of an aerosolizable electronic device,” he says. As one example, the researchers tested the tiny devices in a simulated gas pipeline. The flying machines successfully sailed through the test chamber and detected the presence of carbon particulates or volatile organic compounds along the way and stored this information in memory.
“We put small retroreflectors on the particles — like you have on your bicycles — so they reflect light and allow us to rapidly find the particles,” Koman says.
After the data from the devices is collected, the memory can then be wiped so the miniature machines can be reused.
The researchers’ next steps are to develop particles for additional applications, including as monitors of the human digestive system. “This is the right idea and the right time,” says Strano. “Think of these as proto-robots.”
Strano and Koman had funding from the U.S. Office of Naval Research Multi University Research Initiative. Koman is supported by the Swiss National Science Foundation.
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