A new study has found minuscule diamonds and rubies could be the nanomaterials of choice for researchers aiming to explore cellular and molecular processes inside the living body.
A research team at the ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP) - led by Dr Philipp Reineck from the School of Science - tested the ruby and diamond particles, more than 1,000 times smaller than the diameter of a hair, alongside other nanoparticles for use in biological imaging, and found that they have a higher degree of stability, critical to achieving imaging success.
"Fluorescing nanoparticles can be used as ‘tiny lamps’ that when placed in the body, are able to light up cells and their internal processes," Reineck explained.
"We shine light at the biological sample of interest in a very controlled way and the nanomaterials send light back, helping us to see very specifically what is happening, right down to a molecule and protein level.
"This is the area we’re focused on, exploring how the ‘very small’ can help us in answering some of the very big questions in biology."
In the study published in the journal Advanced Optical Materials, the team compared seven types of fluorescent nanomaterials – organic dyes, semiconductor quantum dots, fluorescent beads, carbon dots and gold nanoclusters, as well as the nano sized diamonds and rubies.
Characteristics tested for included levels of fluorescence brightness and photostability (resistance to change under the influence of light), as well as how efficiently these new materials can be imaged using standard microscopes used in biology.
"Nanomaterials have widely differing characteristics and we need to determine which materials will work best in which imaging application," Reineck said.
"What our study clearly shows is that nanodiamonds and nanorubies are excellent materials for long-term biological imaging.
"These two materials provide acceptable levels of brightness and the best photostability by far, when compared to the other materials that were tested."
In other study findings, Reineck noted clear trade-offs in many of the nanomaterials examined.
"We found that ideal levels of photostability generally mean a sacrifice in brightness and vice versa," he said.
"For example, during testing, the organic dyes and carbon dots were much brighter than the rubies and the diamonds - but photobleaching (or fading) was a major issue, impacting their practical imaging use."
Reineck’s next step will be to work closely with biologists and medical researchers within the CNBP to develop selected nanomaterials so that they can be used with the needed precision and reliability to light-up real-world biological environments.
Future application of the materials will relate to fertility, chronic pain and heart disease research, key focus areas for the CNBP.
"The real treasure isn’t the rubies or the diamonds," Reineck said.
"It will be the way in which we use these materials to shed new light on the incredibly complex processes taking place in the living body, helping us understand a whole host of matters relating to health, wellbeing and disease."
The Centre for Nanoscale BioPhotonics (CNBP) is an Australian Research Council Centre of Excellence, with research focussed nodes at the University of Adelaide, Macquarie University and RMIT University.
A $40m initiative, the CNBP is focused on developing new light-based imaging and sensing tools, that can measure the inner workings of cells, in the living body.
Story: Petra van Nieuwenhoven