The next big revolution in science may come from the world of the very small. Nanotechnology promises to continue to change the way we manipulate the world around us, from using graphene to create atomically-thin night vision contact lenses to coopting algae to transport chemotherapy drugs to specific parts of the body.
A new study published in the journal Nano Letters may represent that next big leap in the nanoscale world: Researchers have revealed how they have created incredibly small robots that automatically heal fractures and cracks. They showcased their new nanoscopic critters fixing broken electronic circuits, but they could also be adapted to repair tears in biological systems – including our own.
“Such a nanomotor-based repair system represents an important step toward the realization of biomimetic nanosystems that can autonomously sense and respond to environmental changes,” the authors write. This has a “wide range of applications, from self-healing electronics to targeted drug delivery.”
The Janus particles, powered by simple chemistry, are automatically driven towards the cracks. Li et al./Nano Letters
Nanobots aren’t actually a new invention. Back in 2012, a study was published demonstrating how DNA origami – folded DNA segments used to make 3D structures – could be made to dynamically change shape and attack tumors. Some of these origami structures can be used as “Trojan horses” that can infiltrate drug-resistant leukemia cells and kill them from the inside.
For this new study, researchers from the University of California, San Diego, and the University of Pittsburgh focused their efforts on the nanobots’ ability to repair, rather than destroy.
When you are unfortunate enough to receive a wound that bleeds, the platelets in your blood become immediately aware of this and rush together to start clotting it. The team wondered if they could create a nanobot to do the same thing for damaged electronic circuitry, so they set out to create them using “Janus” particles – those made of two distinctive chemical hemispheres.
In this case, the particles contained gold on one side and platinum on the other. When dumped into a solution of hydrogen peroxide, the platinum hemisphere chemically reacts and releases a stream of oxygen. This stream is powerful enough to move these particles, all of which are thousands of times smaller than the width of a human hair, through the solution as if they were using miniature jetpacks.
The little nanobots clumping into the scratch. Li et al./Nano Letters
After making a mixture of Janus particles and hydrogen peroxide, the researchers set up a basic electronic circuit designed to power an LED with a battery. They then scratched the circuit, leaving a gouge one-tenth of the width of a human hair, and rendered it unable to power the LED. Finally, the team poured on the Janus particle solution and found that, after just 30 minutes, the light was working again.
The researchers correctly predicted that, as the platinum side rocketed the nanobots through the solution, their gold hemispheres would be attracted to the “energetic wells” produced by the scratch in the circuit. The particles began to quickly pour into these “wells” and bunch up within the crack. As both metals conduct electricity, the circuit was effectively repaired after enough of them gathered together.
If the researchers build on this concept in order to create a biological equivalent, it may not be long before deep wounds are healed using a nanobot solution.
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