Social insects such as ants have colonies that are capable of accomplishing complex tasks and self-organizing and they do it through individual interactions. They can march across large gaps and they can grip the bodies of each other for support that forms a living bridge that allows the colonies to reach to the other side.
What makes it inspiring is the ants' ability to pull off complex tasks of determining which bridges are worth building at all. When ants sees a gap in its path, they don't stop and retreat but rather they mobilize. The nearby ants will trample on its back until its long enough to span whatever gap is in front of them. Remaing Ants will walk across.
Scientists from the Chinese University of Hong Kong were inspired by this swarm behavior of ants, thus making them develop a nanoparticle self-assembly system that can fix broken electrical circuits. The nanoparticles are made of iron oxide and have magnetic properties that can be controlled by a magnetic field. They basically designed the whole experiment in the way that ants align themselves to build a bridge and close the gap.
(Photo : pubs.acs.org)
These nanoparticles are coated with a layer of gold that can conduct electricity. The nanoparticles can self-organize under an external magnetic field and they can turn into a ribbon-like, conductive structure. The thickness and the length of the nanoparticle ribbon can be controlled by fine-tuning the field, and the ribbons dry into hard structures after the magnetic field has been turned off.
The system known as the "microswarm" has demonstrated capabilities of fixing microscale circuits that are broken by making a permanent and stable conductive pathway between two disconnected electrodes, mimicking the functionality of ant bridges and its structure.
This work is an example of how technology and science can be inspired by nature. A large number of nanoparticles, similar to the ant colonies, are able to collectively accomplish tasks that are beyond the capabilities of a single nanoparticle. At the most recent stage, the nanoparticle ribbons can only fix broken circuits on a two-dimensional surface.
The future development of this system should focus on possibly developing an approach to make connections across a three-dimensional gap and improving the precision of nanoparticle assembly, which will then resemble the ant bridges.
