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Pour, shake and stir: How gold particles, DNA and water have the potential to shape the future of medicine

Date:
February 28, 2013
Source:
University of Toronto Faculty of Applied Science & Engineering
Summary:
A diagnostic "cocktail" containing a single drop of blood, a dribble of water, and a dose of DNA powder with gold particles could mean rapid diagnosis and treatment of the world's leading diseases in the near future.
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IBBME PhD student Kyryl Zagorovsky and Professor Warren Chan.
Credit: Image courtesy of University of Toronto Faculty of Applied Science & Engineering

A diagnostic 'cocktail,' containing a single drop of blood, a dribble of water and a dose of DNA powder with gold particles, could one day lead to the treatment of the world's leading diseases.

This homegrown brew is being developed by IBBME PhD student Kyryl Zagorovsky and Professor Warren Chan (IBBME), a Canada Research Chair in Nanobiotechnology, and a recent winner of the NSERC E.W.R. Steacie Memorial Fellowship.

"There's been a lot of emphasis in developing simple diagnostics," said Professor Chan. "The question is, how do you make it simple enough, portable enough?"

Professor Chan's lab studies nanoparticles -- in particular, the use of gold particles in sizes so small that they are measured in the nanoscale. He and his group are working on custom-designing nanoparticles to target and illuminate cancer cells and tumours, with the potential of one day being able to deliver drugs to cancer cells.

Zagorovsky's rapid-diagnostic biosensor will allow technicians to test for multiple diseases at one time with one small sample, and with high accuracy and sensitivity. The biosensor relies upon gold particles in much the same vein as your average pregnancy test. With a pregnancy test, gold particles turn the test window red because the particles are linked with an antigen that detects a certain hormone in the urine of a pregnant woman.

"Gold is the best medium," explained Professor Chan, "because it's easy to see. It emits a very intense colour."

Currently, scientists can target a particular disease by linking gold particles with DNA strands. When a sample containing the disease gene (e.g., Malaria) is present, it clumps the gold particles, turning the sample blue.

Rather than clumping the particles together, Zagorovsky immerses the gold particles in a DNA-based enzyme solution (DNA-zyme) that, when the disease gene is introduced, 'snip' the DNA from the gold particles, turning the sample red.

"It's like a pair of scissors," said Zagorovsky. "The target gene activates the scissors that cut the DNA links holding gold particles together."

The advantage is that far less of the gene needs to be present for the solution to show noticeable colour changes, amplifying detection. A single DNA-zyme can clip up to 600 'links' between the target genes.

Just a single drop from a biological sample such as saliva or blood can potentially be tested in parallel, so that multiple diseases can be tested in one sitting.

But the team has also demonstrated that can transform the testing solution into a powder, making it light and far easier to ship than solutions, which degrade over time. Powder can be stored for years at a time, and offers hope that the technology can be developed into efficient, cheap, over-the-counter tests for diseases such as HIV and malaria for developing countries, where access to portable diagnostics is a necessity.

"We've now put all the pieces together," said Professor Chan.


Story Source:

The above post is reprinted from materials provided by University of Toronto Faculty of Applied Science & Engineering. Note: Materials may be edited for content and length.


Journal Reference:

  1. Kyryl Zagorovsky, Warren C. W. Chan. A Plasmonic DNAzyme Strategy for Point-of-Care Genetic Detection of Infectious Pathogens. Angewandte Chemie International Edition, 2013; DOI: 10.1002/anie.201208715

Cite This Page:

University of Toronto Faculty of Applied Science & Engineering. "Pour, shake and stir: How gold particles, DNA and water have the potential to shape the future of medicine." ScienceDaily. ScienceDaily, 28 February 2013. <www.sciencedaily.com/releases/2013/02/130228171529.htm>.
University of Toronto Faculty of Applied Science & Engineering. (2013, February 28). Pour, shake and stir: How gold particles, DNA and water have the potential to shape the future of medicine. ScienceDaily. Retrieved August 31, 2015 from www.sciencedaily.com/releases/2013/02/130228171529.htm
University of Toronto Faculty of Applied Science & Engineering. "Pour, shake and stir: How gold particles, DNA and water have the potential to shape the future of medicine." ScienceDaily. www.sciencedaily.com/releases/2013/02/130228171529.htm (accessed August 31, 2015).

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