Ontario Tech University researcher: some of the biggest questions in science are answered at the smallest possible scale

Major advancements in our understanding of fundamental science often happen at scales visible by our eyes. A new chemical to help clean up an environmental spill, or even a cell specimen on a microscope slide are examples of materials that are relatively easy for a human to see or envision.

But much of scientific research happens on a scale that is so tiny that the processes are almost impossible to imagine or comprehend. Nisha Agarwal, PhD, an Assistant Professor of Physics with Ontario Tech University’s Faculty of Science, explores the physical properties of elements and materials at these small scales. Her research aims to help scientists and engineers discover new generations of materials that are stronger, lighter, and hopefully more effective or practical for society than anything that’s come before them.

“Advanced materials have the potential to make our lives better in so many ways, be it renewable and sustainable sources of energy, new pharmaceuticals for medicine, or superior-strength products in the way carbon-fibres enhance the performance or durability of a tennis racket,” says Dr. Agarwal. “In fundamental science, new properties and new phenomena are uncovered at the ‘nanoscale’, a super-small scale too tiny for most microscopes to see, that allows researchers to observe and consider an almost infinite number of physical characteristics of a given material.”

How small is nanoscale? A nanometre is one-billionth of a metre. Your fingernails grow by about one nanometre every second. To put nanoscale in perspective: if the diameter of a typical toy marble was one nanometre, then the diameter of the entire Earth would be about one metre.

“For example, think of the element gold, which has well-defined properties such as its golden colour, a property we can see,” explains Dr. Agarwal. “Colour is but one physical property. But when you zoom in on a sample of gold, down to the nanoscale, and you shine light on it with different wavelengths, you can tell even more about the special properties of gold than just its colour. That can be true of just about any compound. Some of those properties can be unique; you might be able to come up with some very creative, technological advances based on properties of a compound that you can only detect at the nanoscale.  That’s nanotechnology.”

Dr. Agarwal has co-authored a highly technical research article on how light starts forming a vortex or ‘tornadoes of light energy’ within a single elliptical ‘nanohole’ in a gold film. These effects will allow for advancing technology by enabling visualization of features much smaller than light itself, also known as ‘super-resolution’ imaging.

The collaborative work with experts from Istituto per i Processi Chimico Fisici – Consiglio Nazionale delle Ricerche and the University of Messina in Sicily, Italy was recently published in the influential journal Nature Scientific Reports*.

“Nanotechnology gives science the ability to do more with less,” says Dr. Agarwal. “Nanotechnology has enabled the efficient storage of data. A computer system once took up the space of an entire room. Floppy disks in the 1990s could only save about 1.4 megabytes of data. With today’s handheld devices, a photograph is about twice that size. Today you would need two full floppy disks to store just that one photo.”

Other everyday products that benefit from nanotechnology research include:

• Fabrication of silver nanoparticles embroidered in fabric with anti-bacterial property to make clothing odour-resistant.
• Cosmetic and skin care products that use nanoparticles to deliver vitamins deeper into the skin.
• Hollow nanoparticles for delivering drugs to a particular site in the human body to kill cancer cells without harming the healthy cells surrounding a tumour.
• Manufacturing of highly efficient lithium-ion batteries that use nanoparticle-based electrodes to power plug-in electric vehicles.
• Use of carbon nanofibres in flame-retardant materials formed by coating with the foam used in furniture.

“You can’t use tongs to pick up a strand of hair; you need tweezers,” says Dr. Agarwal. “To pick up atoms at nanoscale, scientists require what you might call ‘optical tweezers’. When you think about the possibilities of being able to explore the physical-chemical properties of the 118 natural elements we currently know of at ‘super-resolution’, you get the picture. Just like the first image we saw recently in the news of a black hole surrounded by light vortices, we may not yet understand the practical application of the phenomena we are observing. With nanotechnology, we are now at the point of discovering new phenomena previously unknown to humankind. And that’s important for the future of science.”

*Article co-authors:

• Claudia Triolo, University of Messina (Messina, Italy)
• Salvatore Savasta, University of Messina; and Theoretical Quantum Physics Laboratory, Cluster for Pioneering Research, RIKEN (Wako-Shi, Saitama, 351-0198, Japan).
• Alessio Settineri, University of Messina
• Sebastiano Trusso, CNR-IPCF, Istituto per i Processi Chimico-Fisici del CNR (Messina, Italy)
• Rosalba Saija, University of Messina
• Salvatore Patanè, University of Messina

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“Nature is one of the top-leading publishers of papers from any area of science with great potential impact and whose importance extends well beyond the confines of the specific discipline concerned. A Nature publication for Dr. Agarwal highlights her research excellence and the scientific and technological impact of the research she is conducting.”
-Greg Crawford, PhD, Dean, Faculty of Science