Sand-sized batteries can energize microrobots inside the human body

Engineers have developed sand-sized batteries capable of powering tiny robots that can deliver drugs inside the human body.

Engineers at the Massachusetts Institute of Technology (MIT) have reached a breakthrough in nanorobotics that can advance the use of tiny robots in the healthcare and energy sectors.

As robots become smaller, energy storage technology has become increasingly challenging for scientists. Wet chemistry batteries, for example, are limited to millimeter-scale sizes, complicating the task of providing adequate power for tiny robots.

Previous research has demonstrated that microscale devices can be powered by solar energy. However, this approach has a significant drawback: the robots require a continuous light source, such as a laser, to function.

“If you want a small robot to be able to get into spaces that you couldn’t access otherwise, it needs to have a greater level of autonomy. A battery is essential for something that’s not going to be tethered to the outside world,” said Michael Strano, Professor of Chemical Engineering at MIT.

MIT’s recent research, partially funded by the US Army Research Office and the US Department of Energy, has led to the development of a tiny battery that captures oxygen and uses it to oxidize zinc, generating a current with a potential of up to one volt. This current is sufficient to power a small circuit, sensor, or actuator.

The newly developed battery, thinner than a human hair, could power autonomous robots designed to deliver drugs within the human body or locate leaks in gas pipelines.

During the experiment, the battery successfully fueled a robotic arm that can be raised and lowered. The battery could also power a memristor – an electrical component that can store memories of events by changing its electrical resistance – and a clock circuit, which allows robotic devices to keep track of time.

During the current study, the researchers connected their battery to an external device using a wire. However, they plan to integrate the battery directly into the device in the future.

For applications within the human body, the research team envisions using biocompatible materials that would dissolve once the device is no longer needed. Additionally, the team is working on increasing the battery's voltage to expand its potential applications.

“We think this is going to be very enabling for robotics,” commented Strano.

“We’re building robotic functions onto the battery and starting to put these components together into devices. [..] We’re making the basic building blocks in order to build up functions at the cellular level.”