A “cocktail” of a drop of blood, a dribble of water, and a dose of DNA powder with gold particles may lead to quicker diagnosis and treatment of many infectious diseases in the near future.
The new cocktail mix has been developed by researchers from University of Toronto’s Institute of Biomaterials and Biomedical Engineering (IBBME) and its details have been published in the journal Angewandte Chemie .
It consists of the same technology that is used in over-the-counter pregnancy tests and could be used to detect diseases from HPV and HIV to malaria.
IBBME Professor and Canada Research Chair in Nanobiotechnology, Warren Chan said:
“There’s been a lot of emphasis in developing simple diagnostics. The question is, how do you make it simple enough, portable enough?”
Chan studies nano particles and the use of gold particles in small sizes. He and his colleagues are developing custom-designed nano particles to target and brighten cancer cells and tumors, with the hopes that one day, drugs will be able to be directly delivered to cancer cells.
Student Kyryl Zagorovsky’s rapid diagnositc biosensor permits technicians to detect multiple diseases at one time with one small sample and with significant sensitivity and preciseness.
The biosensor needs gold particles in the same way as a pregnancy test. Gold particles change the test window red because the particles are associated with an antigen that finds a certain hormone in the urine of a pregnant woman.
Chan explained, “Gold is the best medium, because it’s easy to see. It emits a very intense colour.”
Now, scientists can pinpoint the exact disease they are looking for by linking gold particles with DNA strands – when a sample that has the disease gene is present, it clumps the gold particles – making the sample blue.
Instead of the particles clumping together, Zagorovsky covers the gold particles with a DNA-based enzyme solution (DNA-zyme) that, when the disease comes in contact, cuts the DNA from the gold particles, making the sample red.
Zagorovsky describes, “It’s like a pair of scissors, and the target gene activates the scissors that cut the DNA links holding gold particles together.”
The benefit is that much less of the gene is required to be present for the solution to show detectable color changes, intensifying detection. One DNA-zyme can cut up to 600 “links” between the target genes.
One drop from a biological sample like saliva or blood may be tested in parallel, in order for multiple diseases to be tested in one sitting.
The researchers also showed that they can alter the testing solution in a powder, making it light and much simpler to ship than solutions which can break down over time.
Powder is able to be saved for years at a time, and gives hope that the technology can be developed into accurate, inexpensive, over-the-counter tests for diseases like malaria or HIV for developing nations.
Written by Kelly Fitzgerald