Austin American-Statesman (12.27.11) - Thursday, January 05,
A University of Texas chemistry and biochemistry professor's
idea for a TB diagnostic is one of 22 concepts to share in
more than $31 million from the Bill & Melinda Gates Foundation
and Grand Challenges Canada. Andrew Ellington has received a
$1.6 million grant to develop a paper-based test for TB using
a patient's saliva.
Current laboratory methods for diagnosing TB require expensive
equipment, refrigeration, and skilled technicians, which can
be scarce in developing countries. If samples must be
cultured, results can take weeks in the best of circumstances.
Ellington said he was inspired to develop the paper test by
learning of the gaps in testing for drug-resistant TB in
Afghanistan, where one of his undergraduate students, Grace
Eckhoff, researched TB. "It was the sort of thing where I was
educated by my own student" about the public health
shortcomings faced by poor countries, he said. Eckhoff has
since graduated and received a prestigious Marshall
Scholarship to study in London.
Ellington's team will work to devise a small paper strip
embedded with bits of synthetic DNA in a sort of biological
circuit board. A patient would spit onto the paper, with a
change in color indicating that the person has TB, including
drug-resistant strains. No refrigeration would be needed.
The challenge is to engineer the DNA circuit board to enhance
the signal from a few molecules of TB bacteria to produce the
color change on paper, said team member and postdoctoral
researcher Xi Chen. Discovering how to best amplify that
signal in the DNA circuit could take years, Ellington said.