Over the past century, the invention of antennas has revolutionised the way our society works. From giant telescopes that allow us to observe the universe of many light-years ago, to the simple TV devices or cellular phones, we are now able to communicate with objects that are physically very far away from us.
Antennas are arrays of conductor elements that can transmit and receive radio waves (or other wavelengths) in particular directions. Broadly speaking, the working wavelength of an antenna is proportional to its size, meaning that the bigger the antenna is, the longer the wavelength it can transmit. As a result, by increasing the array of conductor elements, scientists and engineers have successfully built giant antennas for the observation of the universe.
Going to the opposite direction i.e. the infinite small has instead been much trickier. What if we wanted to look at transports of energy that lie in the visible wavelength (400-700 nm) which is much smaller than anything we could see with our eyes or manipulate with our hands?
The challenge of building a nano-antenna is therefore an interesting task!
For this purpose, my PhD project targets the creation of small constructs made of gold nanoparticles and DNA that could be used as nano-antennas.
A small DNA piece can be folded into three dimensional structures that can capture and immobilise tiny spheres of gold to a gold substrate. The technique is called DNA origami, because the DNA strands are folded just like a piece of paper in the well-known Japanese art. A DNA origami can also accommodate smaller, fluorescent molecules capable of emitting light in the visible range. Combining DNA nanostructures with gold nanoparticles systems allows the creation of small antennas. In this way we are able to trap light into tiny volumes and look at the interaction of small molecules with gold. Mission accomplished! With the ability of looking at extremely small atom movements, we can also target the transport of information at the nanoscale, influencing the next generation of nanophotonics devices.
NanoDTC Associate, a2021
Image adapted from: https://www.nature.com/articles/s41592-021-01355-5.