‘Fishing’ for early cancer diagnosis

Nanocrystals known as Super Dots can identify one diseased cell in millions. Photo: Thinkstock

Nanocrystals known as Super Dots can identify one diseased cell in millions. Photo: Thinkstock

In summary: 
  • The time it takes to test for some cancers and infections can have a profound effect on the outcome for the patient.
  • Technological developments that draw together the latest advances in physics, chemistry and biology could change all that.

Nanoscale photonics technology that can help to diagnose cancer, detect infection and secure passports and bank notes against fraud is in the running for a Eureka Prize for science, to be announced next week by the Australian Museum.

Newly invented nanocrystals known as Super Dots® have the capability to “fish” a diseased cell from millions in a blood or urine sample, for example, and give an accurate and non-invasive early diagnosis of prostate cancer, says the technology developer, Dayong Jin.

“The Super Dots are so bright and so sensitive that we can use them to link to single molecules, to identify the signalling molecules that are the indicators of disease,” says Professor Jin, from the University of Technology Sydney (UTS).

Professor Jin, Professor Tanya Monro, deputy vice-chancellor research and innovation at the University of South Australia, and Dr Brad Walsh, chief executive of biomarker development company Minomic International Ltd, have been selected as Eureka finalists for “excellence in interdisciplinary scientific research”. The technology was developed and patented at Macquarie University by Professor Jin and his team.

Professor Jin and Professor Monro are chief investigators of the ARC Centre for Nanoscale Biophotonics, which explores new approaches to understanding human cellular processes. This “finding a needle in a haystack” technology draws together the latest advances in physics, chemistry and biology.

“When you hear about cancer, for example, or food contamination, or infective disease outbreaks, the cause of this problem is from a single cell,” says Professor Jin. “The current challenge is you don’t have a method to find this very rare cell from the earliest stage.”

For the past two years, they have been working with Dr Walsh’s company to hone the sensitivity of their diagnostic technique for prostate cancer.

Dr Walsh says early screening is particularly important for younger men at risk of prostate cancer but “there’s a lot of pushback from men about not getting tested” through a digital rectal examination or prostate-specific antigen (PSA) test.

“If you can take a body fluid and detect at a very early stage cancer molecules that are coming from the prostate, you’ll be able to then treat them at an early stage or keep an eye on them and treat them at an appropriate time,” says Dr Walsh.

He says the prostate cancer test should be available to Australians in one to two years. He also predicts the technology will extend to other difficult-to-detect cancers, such as ovarian and even – “the holy grail” – pancreatic cancer.

Professor Jin says the team’s development of a “platform technology” means it can be tailored for a variety of applications, including fast, accurate infection detection in children.

“With current testing, you need at least six hours, and a lot of blood, to find out which pathogen it is and whether it’s serious,” says Professor Jin. Every hour spent on testing, one pathogen at a time, is an hour in which children’s lives may be lost, he says.

By using different optically coded Super Dots to recognise specific pathogens, it is possible to do simultaneous detection of hundreds of targets very quickly and using only a small blood sample.

“Because the Super Dots offer super sensitivity, if there is a single molecule representing the infection, you can quickly identify it,” says Professor Jin.

The diverse impact of Super Dots technology, with its labyrinth of optical barcodes, extends to high-density data storage and counterfeiting applications to protect passports, bank notes and pharmaceuticals. “Secret signatures” invisible to the naked eye and laser scanners are almost “impossible to crack”, says Professor Jin.

In the run-up to Eureka prize night, Professor Jin is juggling a need to be patient with an urge to keep pushing his technology forward.

“Young people like me – I need more patience. On the one hand you’re really excited about technology and knowledge and working as a team, showing it works in the lab. But on the other side, you need to be more patient to make sure your experiments and all the operational procedures comply with regulations. And you need support from the public.”

In the next couple of years, he says, attention will turn to the hot new field of “theranostics”, combining therapy and diagnostics, which has the potential to supercharge the impact of his team’s Super Dots.

The Australian Museum Eureka Prizes will be announced at an awards dinner to be held in Sydney Town Hall on Wednesday August 26.

Health and Science, Brink