Tech Briefs Magazine - February 2023 - ST20

ronment, they achieved effective flow measurements
for a wide range of airflow
speeds from (30 -170) meters per second.
The sensor demonstrated both high flexibility
and scalability. " The circuits around
the sensor can be pulled out using a flexible
printed circuit board and installed in a
different location, so that only a thin sheet
is attached to the measurement target,
minimizing the effect on the surrounding
flow, " said Professor Motosuke.
The team estimated the heater output to
vary as the one-third power of the wall
shear stress, while the sensor output comparing
the temperature difference between
two oppositely placed sensors
demonstrated a peculiar sinusoidal oscillation
as the flow angle was changed.
The developed sensor has the potential
for a wide range of applications in industrial-scale
fluid machinery that often involve
complex flow separation around three-dimensional
surfaces. Moreover, the working
principle used to develop this sensor can
be extended to flows at speeds that are far
lower than high-speed subsonic airflows.
" Although this sensor is designed for fast
airflows, we are currently developing sensors
that measure liquid flow and can be
attached to humans based on the same
principle. Such thin and flexible flow sensors
can open up many possibilities, " said
Professor Motosuke.
This novel MEMS sensor could be a
game-changer in the development of efficient
fluid machineries with reduced detrimental
effects on our environment.
For more information, contact
mediaoffice@admin.tus.ac.jp.
New Nanoparticle-Based Sensors Can Measure Residual
Herbicides in Food
Newly developed, low-cost tests that use nanoparticles to detect chemicals can
accurately measure tiny amounts of two potentially harmful herbicides in fruits,
vegetables, and their products.
Washington State University, Pullman, WA
R
eporting
in the journal Food
Chemistry, a Washington State
University research team used two
testing methods to measure the levels
of two herbicides, namely atrazine
and acetochlor, in samples of apples,
strawberries, cabbage, corn, and fruit
juices. The work shows the real-world
viability of their easy-to-use and inexpensive
methods of testing.
" We applied this technology for real
sample detection - which is an important
step in moving towards commercialization, "
said Annie Du, research
professor in WSU's School of
Mechanical and Materials Engineering
and the principal investigator of the
project.
a signal. The amplification allows the
researchers to know that tiny amounts
of the chemicals are present and at
what level.
In this latest work, the researchers
used the nanoparticles in two types of
tests to measure two chemicals simultaneously.
The chemicals were spiked
into fruit and vegetable samples that
were pureed in a blender.
The Food and Drug Administration
(FDA) regularly tests a broad range of
commodities for approximately 800
pesticide residues, and producers are required
to keep the chemical residues on
food below a certain level that is considered
safe. The two herbicides the researchers
measured are widely used in
crop production in the U.S. At high exposures,
they are potentially toxic for
people and have been linked to a range
of maladies from allergies to hormone
disruption to cancer.
The Food and Drug Administration (FDA) regularly tests
a broad range of commodities for approximately 800
pesticide residues, and producers are required to keep
the chemical residues on food below a certain level that
is considered safe. (Image: Washington State University)
" We want to come up with a low-cost
method that can be used in the field or in
the laboratory, " said Bernie Van Wie, corresponding
author on the paper and a
professor in WSU's Gene and Linda
Voiland School of Chemical Engineering
and Bioengineering.
Doing the testing, however, currently
requires sophisticated and expensive instruments
as well as a trained technician.
20
In the past few years, the researchers
have developed and patented their idea,
in which nanoparticles of palladium and
platinum are used to amplify the signals
of molecules. The nanoparticles attach to
an antibody, which recognizes the chemical
and then stimulates the production of
www.techbriefs.com
One of the tests uses the palladium-platinum
nanoparticles to catalyze
a reaction that causes a color change
in a sample when the herbicide is
present. The test can be done using a
small unit that can be carried into the
field. The other test the researchers
developed uses the nanoparticle in a
low-cost paper strip that looks like a
COVID-19 or pregnancy test and can
be read with a smartphone reader.
The tests were sensitive enough to measure
the chemicals down to the maximum
acceptable levels and were validated
using traditional testing methods.
" We're actually able to detect below
the maximum concentration limits if
there's any pesticide or herbicide in the
sample, " said Van Wie. " That's good because
while this can be done by other
methods, this method is low-cost and
portable in the field. "
For more information, contact Annie
Du at annie.du@wsu.edu.
Sensor Technology, February 2023
http://www.techbriefs.com
Tech Briefs Magazine - February 2023

Table of Contents for the Digital Edition of Tech Briefs Magazine - February 2023
