A tiny battery the width of a human hair could be used to power autonomous robots for drug delivery within the human body, researchers have discovered.
A team from the Massachusetts Institute of Technology (MIT) has developed this cell-sized battery, which measures just 0.1 millimeters long and 0.002 millimeters thick.
The battery functions by capturing oxygen from the air and using it to oxidize zinc, generating up to 1 volt of current -- enough to power small circuits, sensors, or actuators.
Professor Michael Strano, the study's senior author, remarked, "We think this is going to be very enabling for robotics." He added, "We’re building robotic functions onto the battery and starting to put these components together onto devices."
Previously, other researchers had developed microscale robots powered by solar energy, but those needed constant light sources like lasers, earning them the nickname ‘marionettes’.
According to Strano, these marionette systems aren't tethered to external power sources, meaning they don't require batteries. Still, for true autonomy, particularly to reach inaccessible places, small robots need batteries.
The high energy density of zinc-air batteries provides longer lifecycles than most battery kinds, which is why they are commonly seen in hearing aids.
To put it simply, the MIT scientists constructed the battery with zinc and platinum electrodes embedded within SU-8, a polymer often used for microelectronics.
When these electrodes mix with oxygen molecules from the air, zinc is oxidized, releasing electrons toward the platinum electrode, which results in current flow.
During experiments, the researchers established the battery could energize a simple actuator, allowing it to raise and lower, as well as power other components like memristors and clock circuits.
These components have significant applications, such as storing data by changing their electrical resistance and keeping robotic devices on time.
The battery also powers various sensors sensitive to environmental chemicals, featuring one made from atomically thin molybdenum disulfide and another from carbon nanotubes.
"We’re constructing the basic building blocks to develop functions at the cellular level," Strano noted.
While the current study linked the battery to external devices via wires, future designs will integrate the battery within the robots themselves.
Strano emphasized, "This is going to form the core of many of our robotic efforts. You could build robots around energy sources like one would design electric cars around batteries."
Future ambitions include tiny robots injected directly inside the human body, where they could localize and release drugs such as insulin. Authorities are considering using biocompatible materials for these robots, which would disintegrate once their job is done.
The research team is also exploring ways to amplify the battery's voltage to expand its potential applications.
The study, published recently, has drawn interest because it opens up new possibilities for the emerging field of medical robotics and autonomy.
The project's lead authors include Ge Zhang, Ph.D., and graduate student Sungyun Yang.
This innovation not only signifies immense strides for robotics but also paints the future of healthcare automation with the potential for vastly improved medical treatments.
With these tiny, powerful batteries, the potential to revolutionize drug delivery systems and other applications is now on the horizon, waiting for full realization.
