By mimicking nature’s
own sensing mechanisms, bioengineers at University of California, Santa Barbara
(UC Santa Barbara) and University of Rome Tor Vergata have designed inexpensive
medical diagnostic tests that take only a few minutes to perform. Their
findings may aid efforts to build point-of-care devices for quick medical
diagnosis of sexually transmitted diseases (STDs), allergies, autoimmune
diseases, and a number of other diseases. The new technology could dramatically
impact world health, according to the research team.
The rapid and
easy-to-use diagnostic test consists of a nanometer-scale DNA
“switch” that can quickly detect antibodies specific to a wide range
of diseases. The research is described in an article published in the Journal of the American Chemical Society.
The design was created
by the research group of Kevin W. Plaxco, a professor in UCSB’s Department of
Chemistry and Biochemistry. He noted that, despite the power of current
diagnostic tests, a significant limitation is that they still require complex
laboratory procedures. “Patients typically must wait for days or even
weeks to receive the results of most STD tests,” says Plaxco. “The
blood sample has to be transported to the lab, its content analyzed by trained
personnel, and the results sent back to the doctor’s office. If we can move
testing to the point of care, it eliminates the lag between testing and
treatment, which would enhance the effectiveness of medical interventions, and,
for infectious diseases like STDs, reduce transmission.”
The key breakthrough
underlying this new technology came from observing nature. “All creatures,
from bacteria to humans, monitor their environments using amazing ‘molecular
nanoswitches’ that signal the presence of a specific target by changing their
structure,” says Alexis Vallée-Bélisle, a postdoctoral scholar and
co-first author of the study. “For example, on the surface of our cells,
there are millions of receptor proteins that detect various molecules by
switching from an ‘off state’ to an ‘on state.’ The beauty of these switches is
that they are able to work directly in very complex environments such as whole
blood.”
Plaxco’s research group
teamed with Francesco Ricci, professor at University of Rome Tor Vergata and
co-first author of the paper, to build synthetic molecular switches that signal
their state via a change in electric current. This change in current can be
measured using inexpensive electronics similar to those in the home glucose
test meter used by diabetics to check their blood sugar. Using these
“nature-inspired” nanoswitches, the researchers were able to detect
anti-HIV antibodies directly in whole blood in less than five minutes.
“A great advantage
of these electrochemical nanoswitches is that their sensing principle can be
generalized to many different targets, allowing us to build inexpensive devices
that could detect dozens of disease markers in less than five minutes in the
doctor’s office or even at home,” says Ricci.
The authors note that it
may take several years to bring the devices to the market.
