January 13, 2016

Hybrid nanocrystals to change way cancer is diagnosed and treated

Scientists discover new tools that could change how cancers and brain diseases are diagnosed and treated.

Researchers in the field of nanotechnology engineering, including a team from UOW’s Institute for Superconducting and Electronic Materials (ISEM), have discovered new tools that could change how cancers and brain diseases, such as dementia and Parkinson’s disease are treated in the future.

The latest findings, just announced in Nature Communications, promise a new generation of nanoscale crystals which will give scientists the tools they need to develop less costly and more efficient ways of creating new cancer treatments.

The use of nanocrystals offers more defined images of cancer cells to not only improve surgery procedures but speed up recovery for patients.

The latest development in this field has been discovered by a research team including Professor Dayong Jin (ARC Future Fellow in Biophotonics, Nantechnology and Medical Biotechnology) from the University of Technology Sydney; Professor Shi Xue Dou (ISEM Director); ISEM Research Fellow Dr Yi Du; and their collaborators from the ARC Centre of Excellence for Nanoscale Biophotonics at Macquarie University and the National University of Singapore.

The new hybrid nanocrystals have the potential to act as a vehicle for better targeted human drug delivery.

“Now that nanoparticles can be precisely controlled to create different shapes and sizes, researchers can begin to investigate whether the new type of nanoparticles have an impact on energy conversion in photocatalytic process and the transportation of drugs within the body,” Professor Dou said.

The team’s discovery could form new solutions to getting around the body’s immune system response in the targeted treatment of cancerous cells, which causes both the healthy and diseased cells to die.

“At this stage the treatment for cancer is applying radiation or chemical drugs which tends to be very aggressive,” Professor Jin said. “You might kill the cancer cells, but you can also kill up to 70 to 90 per cent of the healthy cell.

“We see similar problems in the treatment of neurological diseases. There are a lot of drugs to treat these types of diseases, but the problem is the blood brain barrier which protects the brain from infections—a lot of the time the drug tends to circulate in the blood system and not the brain.

“We need to find a new vehicle for drug delivery that allows the healthy cell and blood brain barrier to recognise the drug as a ‘friend’ and not an ‘enemy’.”

The latest research is aimed at developing this new vehicle.

The breakthrough has been a result of more than 800 synthesis experiments carried out for the past three years by Macquarie University student Mr Deming Liu who created a library of 800 different choices of new shaped nanocrystals formed from ordered atom clusters. The different shaped or ‘hybrid’ nanocrystals were systematically characterised by the state-of-the-art facilities at Wollongong’s ISEM. The nanocrystals act as new tools, or a new molecular tag and a potential new vehicle for targeted drug delivery.

Professor Jin said the new type of nanocrystal could also lead to clearer diagnostic bio-imaging such as MRI scans and X-rays.

“Hybrid nanocrystals are multifunctional and able to do different things simultaneously. For example, one can design a super nanoparticle that has optical, magnetic and chemical responses which allows for multiple molality imaging of the disease and [eventually] super high resolution images,” Professor Jin said.

“Having precise diagnostics is also important because when a surgeon operates they need to understand exactly where the tumour is.

“If higher resolution imaging is available, the surgeon will be able to see a precise boundary between the healthy cell and tumour cell which will result in a better outcome for the patient.”

Now that nanoparticles can be precisely controlled to create different shapes and sizes, we can begin to investigate whether the new type of nanoparticles have an impact on the transportation of drugs within the body, according to Professor Dou.

The new hybrid nanocrystals are opening up not only exciting channels on the medical front but also provide an ideal solution to enhance light energy usage of photocatalysts. [Photocatalysis is a reaction which uses light to activate a substance which modifies the rate of a chemical reaction without being involved itself.]

Energy and environmental issues have been a crucial problem in recent decades with increasing consumption of fossil fuels and consequently, more pollutant emissions due to the population explosion and rapid industrialisation.

Professor Dou said to alleviate the crisis, research and development on alternative types of renewable clean energy such as hydrogen fuel, solar energy, and wind power are essential.

“Photocatalysts possess properties that allow for an effective direct transfer of photo-energy in highly reactive chemical species. However, the visible light photocatalytic performances of all existing materials are very low due to low-efficiency usage of visible light.”

It’s at this point the joint research team’s efforts using hybrid nanocrystals comes to the foreground.

As Dr Yi Du points out: “In terms of their applications in photocatalysis, the hybrid nanocrystals add to the photocatalytic system working as energy converters, which convert visible light to the high-energy UV light that can boost the chemistry of oxygen reduction and generation of hydrogen from water -- the two most important reactions in photocatalysis.”

“Heterogeneous photocatalytic system consisting of these nanocrystals and photocatalysts hold a great potential for simultaneous Hydrogen production and pollutants’ degradation simply driven by solar light,” Dr Du said. 

The research paper, ‘Three-dimensional controlled growth of monodisperse sub-50 nm heterogeneous nanocrystals’ was authored by Deming Liu, Xiaoxue Xu, Yi Du, Xian Qin, Yuhai Zhang, Chenshuo Ma, Shihui Wen, Wei Ren, Ewa M. Goldys, James A. Piper, Shixue Dou, Xiaogang Liu and Dayong Jin.

Photo: Dr Yi Du (foreground) with the Director of the Institute for Superconducting and Electronic Materials, Professor Shi Xue Dou, alongside an optical microscope which can observe photocatalytic processes at the atomic/nanoscale level.