Colonies of social insects are capable of self-organizing and
accomplishing complex tasks through individual interactions. For
example, to march across large gaps, ants grip the bodies of each other,
forming a living bridge that allows the colonies to reach the other
side. Inspired by this swarm behavior of ants, scientists from the
Chinese University of Hong Kong developed a nanoparticle self-assembly
system that can fix broken electrical circuits.
The nanoparticles, made of iron oxide, have magnetic properties and can be controlled by a magnetic field. They are coated with a layer of gold that can conduct electricity. Under an external magnetic field,
the nanoparticles can self-organize into a ribbon-like, conductive
structure. The length and thickness 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. This "microswarm" system has demonstrated
capabilities of fixing broken microscale circuits by making a stable and
permanent conductive pathway between two disconnected electrodes,
mimicking the structure and functionality of ant bridges.
This work is an interesting example of how science and technology can
be inspired by nature. Similar to the ant colonies, a large number of
nanoparticles are able to collectively accomplish tasks that are beyond
the capabilities of one single nanoparticle. At the current stage, the
nanoparticle ribbons can only fix broken circuits on a two-dimensional
surface. Future development of this system should focus on improving the
precision of nanoparticle assembly, and possibly developing an approach
to make connections across a three-dimensional gap, which will then
truly resemble the ant bridges.