Researchers at MIT have created cell-sized robots that may someday be used to inspect and analyze hard-to-reach locations, from oil pipelines to the human body.

The trick: Adding tiny electronic circuits to tiny, floating particles.

The nano-circuits, made of two dimensional materials and measuring just 100 micrometers across, operate by piggybacking on minuscule particles called colloids – molecules that stay suspended indefinitely in a liquid or in air.

Michael Strano, chemical engineering professor at MIT and senior author of the study published in this month’s Nature Nanotechnology, sees a maneuverability advantage to grafting complete, intact electronic circuits onto colloids.

“Colloids can access environments and travel in ways that other materials can’t,” Strano said in a recent MIT press release.

Optical images show circuits made by the research team, attached to particles just a few hundred nanometers across. (Image Credit: MIT)

Think dust particles, for example, which float indefinitely in the air, supported by the random motions of colliding air molecules. Similarly, colloids held in liquid never settle out.

Now imagine MIT’s tiny device, suspended, as it travels through a pipeline – an application that the researchers consider valuable especially for the oil and gas industry.

Current pipe inspection requires expensive instrumentation, as well as workers having to physically move along the entire distance of the line.

In theory, say the researchers, the cell-sized robots could be placed in one end of the pipeline, carried along with the oil flow, and then removed at the end, providing a record of the conditions along the way, including the presence of contaminants.

MIT’s current nanomachines can detect chemicals, like ammonia or soot from pipe exhausts. The devices also contain tiny location-tracking retroreflectors, and can be interrogated through probes to deliver their data.

And more applications are possible, according to MIT postdoc Volodymyr Koman, the paper’s lead author.

“We created microrobots that can access otherwise inaccessible places,” Koman told Tech Briefs. “We are excited about the broad range of their applications, ranging from biomedical diagnostic devices to environmental probes to study geological samples and biochemical reactors.”

The miniature robots, for example, could be used as diagnostic tools in the body, passing through the digestive tract and searching for signs of inflammation or other disease indicators.

Additionally, the nanomachines may someday be placed in midair as well, monitoring the compounds present inside a chemical processor or refinery.

The Power of Tiny Robots

In addition to chemical detection, the nanorobots also respond to light, allowing the devices to be self-powered.

A photodiode provides just the right amount of energy to run the robots’ circuits and perform the basic commands of sensing information, storing the data, writing it to 1-bit memory, and reading it out.

Traditional microchips, made from silicon or CMOS, require high amounts of energy, leading Koman to try out two-dimensional electronic materials, including graphene and transition-metal dichalcogenides, which he discovered could be attached to colloid surfaces, remaining operational even after being launched into air or water.

“Conventional electronics is power-thirsty and requires high voltages,” Koman told Tech Briefs. “We found that 2D materials can operate under nanowatts of power that was supplied to them remotely via light.”

The attachment to the colloids give the devices a mechanical rigidity, making them large enough to become entrained in a given flow. The autonomous particles – a key feature, according to Koman – contain the electronics for power generation, computation, logic, and memory storage.

“Demonstrating a complete autonomous circuit is a milestone for us,” said Koman. “Thanks to the modularity of electrical components, we plan to put more sensors and more memory in future devices, making them perform even more complex tasks.”

In ongoing work, the team hopes to add communications capabilities to allow the particles to deliver their data without the need for physical contact.

What do you think? Where do you see cell-sized robots being used? Write your responses in the comments section below.