Tech Briefs Magazine - December 2021 - 29

Detection occurs in two major steps.
First, the sample is processed in a mi -
crofluidic device, which requires only a
small sample volume. Next, the processed
sample is loaded onto the miniaturized
sensor, where detection occurs. The
microfluidic device and sensor can be
packaged up into a rugged briefcase that
can be brought anywhere in the world.
The device's technology is based on a
benchtop waveguide-based optical bio -
sensor. The sensing system detects analytes
on a planar optical waveguide surface
in a very small (~200nm) field. To
produce the sensing field, a laser is coupled
at a critical angle of incidence into
the planar waveguide and total internal
reflection of light occurs between the
layers of the waveguide due to their different
refractive indices. This causes an
evanescent field to radiate off the surface
of the waveguide where fluorescent
molecules are detected.
PEGASUS can rapidly detect infection
in a doctor's office, a remote clinic,
or a laboratory. In the case of bacterial
infections, it can discriminate
among Gram-positive, -negative, and
indeterminate sources, without prior
knowledge of the infection type, in 15
to 30 minutes. Another potential impact
is in the field of bio-surveillance. Since
the biosensor can be used in remote
areas of the world and can detect a
variety of biological molecules from a
variety of sources, it can have impact in
monitoring the presence of potential
biothreat agents or outbreaks. The sensor
can detect the presence of biomolecules
from food sources or the water
supply and can help to identify un -
known white powders that are mailed
in suspicious packages or spilled on the
highway.
For more information, contact Nancy
Ambrosiano at nwa@lanl.gov; 505-699-1149.
Sensors Eliminate Sparking in
Hydrogen Vehicles
The optical-based sensor detects the presence of hydrogen
without electronics, making the process much safer.
University of Georgia, Athens
H
ydrogen as a clean, renewable alternative
to fossil fuels is part of a sustainable-energy
future; however, lingering
concerns about
flammability have
limited widespread use of hydrogen as a
power source for electric vehicles. Hydro -
gen vehicles can refuel much more quickly
and go farther without refueling than
today's electric vehicles, which use battery
power. But one of the final hurdles to
hydrogen power is securing a safe
method for detecting hydrogen.
Researchers have developed an inexpensive,
spark-free, optical-based hydro -
gen sensor that is more sensitive - and
faster - than previous models. Most
com mercial hydrogen sensors detect
the change of an electronic signal in
active materials upon interaction with
hydrogen gas, which can potentially
induce hydrogen gas ignition by electrical
sparking. The new sensor detects
the presence of hydrogen without electronics.
Hydrogen
power has many more
applications than powering electric vehicles
and flammability mitigation technologies
are critical. Robust sensors for
Tech Briefs, December 2021
Cov
hydrogen leak detection and concentration
control are important in all stages
of the hydrogen-based economy including
production, distribution, storage
and utilization in petroleum processing
and production, fertilizer, metallurgical
applications, electronics, environmental
sciences, and health and safety.
The three key problems associated
with hydrogen sensors are response
time, sensitivity, and cost. Current mainstream
technology for H2 optical sensors
requires an expensive monochromator
to record a spectrum, followed by analyzing
a spectral shift comparison.
The new nanosensors go from detection
of hydrogen at around 100 partsper-million
to 2 parts-per-million, at a
cost of a few dollars for a sensing chip.
The new optical device relies on the
nanofabrication of a nanosphere template
covered with a palladium cobalt
alloy layer. Any hydrogen present is
quickly absorbed, then detected by an
LED. A silicon detector records the
intensity of the light transmitted.
For more information, contact Sara Free land
at freeland@uga.edu; 706-542-8077.
www.techbriefs.com
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Contact our application engineers:
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Tech Briefs Magazine - December 2021

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