Diamonds light up the brain

8 January 2020:

From capturing images of cellular processes to sensing electromagnetic fields in extreme environments, researchers at the Centre for Nanoscale BioPhotonics are harnessing the unique properties of diamonds for a wide variety of applications.

Dr Philipp Reineck, associate investigator at CNBP and Research Fellow at RMIT University, is exploring how diamond fluorescence can be used to sense electrical impulses in the brain.

This research project landed Reineck a prestigious Discovery Early Career Researcher Award (DECRA) from the Australian Research Council in November 2019.

“Diamonds have some extreme properties,” says Reineck. “We can make diamonds that never stop fluorescing. These diamonds are extremely stable, which is a valuable property in many fluorescence imaging and sensing experiments.”

The remarkable stability of diamond could also be used to make new light-based sensors for extreme environments.

“Most materials change and degrade after being exposed to light for a long time,” says Reineck. “This doesn’t happen with diamonds.”

In diamond, fluorescence originates from individual atomic defects in the diamond crystal lattice. These defects can occur naturally or they can be created, for example, by creating a ‘vacancy’. This is done by removing one carbon atom from the lattice and replacing a neighboring one with a nitrogen atom. The defect can then emit single particles of light – also known as photons.

Philipp Reineck in one of RMIT’s optics labs. Credit: RMIT University

Beyond imaging and sensing in biology and other research areas, diamond fluorescence is also useful in quantum physics applications.

“Physicists love it, because you can do quantum experiments at room temperature with fairly simple equipment,” says Reineck. “Most experiments with other ‘quantum materials’ have to be conducted at close to absolute zero temperature, which is difficult, expensive, and time-consuming.”

Reineck is also trying to understand the mechanisms underlying diamond fluorescence and what causes particular defects in the diamond crystal to glow. A major challenge in this area, he says, is figuring out why the optical properties of diamond particles vary depending on their size and shape.

“When we go from pieces that are a few millimetres in size to tiny nanoparticles, the properties can change quite drastically,” says Reineck. “I would like to contribute to our understanding of this, which will allow us to make much better particles for many applications.”

Reineck’s career began in Germany where he completed a diploma in physics and nanotechnology at Ludwig-Maximilian-University in Munich.

After moving to Australia, Reineck did his PhD at Monash University where he investigated how metal nanoparticles can be used to make better solar cells.

After a stint as a postdoctoral research fellow at Swinburne University, Reineck joined CNBP in 2014 to explore how nanomaterials could be used to develop state-of-the-art biomedical imaging and sensing technologies.

With his interdisciplinary background, Reineck says that he’s keen to keep his research interests broad.

Reineck’s plan is to further establish himself in the diamond research field and to explore how new materials can be applied to other areas he’s worked in, such as renewable energy.