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Researchers at the University of
Toronto have created a cheap, rapid, easy-to-use testing method for infectious
diseases. The test is not yet ready for widespread use, but researchers contend
that it can make quick, accurate diagnoses available even in developing
countries, speed up detection and response to developing pandemics, and help
slow development of drug-resistant disease.
The researchers stated that the
science behind the test is not new, but what is new is the way it is being
applied. At present, DNA enzymes are used as the bio-sensor and gold
nanoparticles are used as the color-changing element in over-the-counter
pregnancy tests. According to Kyryl Zagorovsky, a PhD student at the
university’s Institute of Biomaterials and Biomedical Engineering (IBBME), the
two materials have not been put together before. Zagorovsky and Warren Chan, an
IBBME professor and the other lead developer of the test, mixed the gold
nanoparticles in solution with linked two-part DNA enzymes that bonded with the
nanoparticles, clumping them so they showed a purple color. When a pathogen
reaches the DNA enzyme, it causes a change that awakens the enzyme and cuts the
chemical links holding the nanoparticles together. Users see this reaction as a
change of color from purple to red. A more specific reading of the severity of
the infection is done by using a standard TLC plate. Since no special
fluorescent equipment or refrigeration is required, this test is ideal for
places with poor medical infrastructure.
Zagorovsky explained that there is
no limit to the number of diseases the IBBME method can detect through parallel
testing, but a different DNA enzyme would be needed for each. He and Chan are
focusing first on malaria, HIV, hepatitis, and STDs. Chan compared the IBBE to
a quick malaria test called Binax NOW, and showed how the IBBME was quicker and
more efficient. Also, Binax NOW costs about $25 per test, which is more than
the $3 he estimates for a commercial version of the IBBME.
Chan reasoned that diseases become
resistant because many individuals are treated based on symptoms, which may not
be an exact indicator of the specific infection. If the drugs do not kill the
infection, the infection can mutate and become resistant. With the IBBE, the
specific infection can be diagnosed quickly and the right treatment given, thus
preventing resistance. Also, rapid test results and centralized data mapping
can make it easier to spot developing pandemics. According to Zagorovsky, the
test has been tried with genetic imitations of HIV and malaria, but trials in
Africa and South Asia with actual disease samples should be completed in
summer. After satisfactory completion of the trials and regulatory approval,
the researchers will need some type of partnership to produce the tests
commercially.
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dedicated to enhancing the quality of life for HIV positive individuals and
empowering people to make healthy choices to prevent the spread of the HIV
virus. To learn more about The Friends of AIDS Foundation, please visit: http://www.friendsofaids.org.
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