The photo at left
shows the gold biosensor developed by Rebecca Lai, associate professor of
chemistry at the
University of Nebraska. The DNA probe is immobilized on a gold electrode
contained within
the circle. A water sample, as small as 10 microliters, is applied to the
sensor
through the center
of the crystal cube. The white, green and red leads attached to the contact
pads connect to a
handheld power source. The center diagram illustrates how gold ions
connect two
strands of adenine and hinder electron
(February 21, 2016) Instead
of a pan and a pick ax, prospectors of the future might seek gold with a
hand-held biosensor that uses a component of DNA to detect traces of the
element in water.
The gold sensor is the latest in a series of metal-detecting
biosensors under development by Rebecca Lai, an associate professor of
chemistry at the University of Nebraska-Lincoln. Other sensors at various
stages of development detect mercury, silver or platinum. Similar technology
could be used to find cadmium, lead, arsenic, or other metals and metalloids.
A primary purpose for the sensors would be to detect water
contaminants, Lai said. She cited the August 2015 blowout of a gold mine near
Silverton, Colorado, which spilled chemicals into nearby rivers, as well as the
ongoing problems with lead-tainted water supplies in Flint, Michigan.
Rebecca Lai
Fabricated on paper strips about the size of a litmus strip,
Lai's sensors are designed to be inexpensive, portable and reusable. Instead of
sending water samples away for time-consuming tests, people might someday use
the biosensors to routinely monitor household water supplies for lead, mercury,
arsenic or other dangerous contaminants.
But Lai also is among scientists searching for new and
better ways to find gold. Not only aesthetically appealing and financially
valuable, the precious metal is in growing demand for pharmaceutical and
scientific purposes, including anti-cancer agents and drugs fighting
tuberculosis and rheumatoid arthritis.