logo

03 July 2017

University of Melbourne nitrogen-vacancy diamonds scan molecules

There’s always been something illuminating about diamonds. But University of Melbourne researchers are now using them as a ‘magnifying lens’ to the quantum world.

DIAMONDS just got much more valuable. Thanks to Australian research, they will soon become ‘lenses’ offering a powerful view of individual molecules and atoms.

The ability to do this is at the heart of modern drug and materials research.

But current techniques rely on very large and power hungry devices that offer an averaged impression of a limited spectrum of molecule types.

Now, the not-so humble diamond appears on the brink of making clearer, easier observations of a greater variety of nanoscale particles.

“In essence, we’re actually trying to find a way to do measurements that are actually impossible with any machine built anywhere today,” says University of Melbourne postdoctoral researcher Dr Alastair Stacey.

Now a team from the Centre of Excellence for Quantum Computation and Communication Technology and the University of Melbourne have demonstrated diamonds with a unique ‘flaw’ can be used to ‘probe’ the spin of individual atoms and how they connect to others in a molecular chain.

Understanding how such molecules are shaped and interact with each other means new drugs can be tailored to tackle particular needs.

“With these advances in quantum sensing technology, we are opening the door to a new world of scientific investigation that could lead us to gain a better understanding of the smallest building blocks of life.” says project leader Professor Lloyd Hollenberg.

Details of the new tool have been published in today’s edition of the science journal Nature Communications.

SPLINTER IN THE DIAMOND EYE

Dr Stacey says the diamonds will hopefully allow scientists to build a ‘quantum microscope’.

“We’re trying to make tiny MRI machines which are cheaper, and capable of imaging life at a much smaller scan than a hospital MRI is currently capable of. We are trying to get down to the scale of atoms,” he says.

It’s not a new idea. A limited form of scanning at the nanoscale is being used already. But the nuclear MRI process is complex and energy-hungry, involving large magnetic coils and powerful microwave fields.

Lead author James Wood describes the technique as “a dramatic simplification of the nuclear detection process, where we essentially shine light on an atomic-sized defect in diamond and observe its natural response, at a fundamentally quantum level, to the target nuclear spins nearby”.

This is where the tiny flaw comes into play.

University of Melbourne researchers have beamed green lasers into a diamond’s nitrogen-vacancy (an atom-sized hole with a nitrogen atom alongside it, which then glows red) to ‘probe’ the atomic structure of molecules.

University of Melbourne researchers have beamed green lasers into a diamond’s nitrogen-vacancy (an atom-sized hole with a nitrogen atom alongside it, which then glows red) to ‘probe’ the atomic structure of molecules.Source:Supplied

It involves a single missing carbon atom in the tightly packed lattice that creates the diamond’s immensely tight structure. And one of the atoms alongside that hole must be a nitrogen atom.

It’s called a ‘nitrogen-vacancy’.

This ‘flaw’ can occur in natural or manufactured diamonds and gives them an unusual pink colour.

But it can also do much more.

The atom-sized hole can capture two electrons which — with additional light — act as a high resolution ‘probe’ to the quantum world.

“The whole point of the quantum nanoprobe is not only to make it simpler and easier, but do things you can’t do with large machines anyway,” Dr Stacey says.

QUANTUM RESOLUTION

Current molecular imaging machines — called synchrotrons — use intense X-rays to get an ‘averaged’ image of what molecules look like. This process can damage the molecules and only works on certain types.

“So there’s also a whole range of natural molecules we simply can’t get any image from at all,” Dr Stacey says. “We’re trying to plug that gap to improve drug discovery.”

Put simply, the size and sensitivity of the diamond-based device can enable researchers to get much better images from much smaller samples.

And it doesn’t damage the sample it is imaging.

Researchers at the moment are generally working at the “few-atoms scale” on MRI-type machines, Dr Stacey says. “The best conventional MRI can do is 10s of microns, which is millions of times larger in volume than our new approach.”

Such scanning has already been immensely valuable to research.

“Drugs work is very physical, very much shape dependent,” Dr Stacey says. “We need to understand its shape and that of the thing it is supposed to interact with for it to work.”

Once the mechanism of bio-molecular structures is understood, more targeted and effective therapeutics can be designed.

The diamond quantum ‘lens’ could expand the potential for new discoveries enormously.

“We don’t know exactly where it’s going to go,” says Dr Stacey. “The thing that excites us is to — in the future — be essentially able to see the shape and composition of molecules we have simply no idea about now.”

Please follow and like us:

Share
#

Write a comment

10+10 = ?