“We observed that even tiny electro-
chemical changes in the fuel cell were
translated into large, easily detectable
electrical signals through the OECT,”
said Ravindra Saxena, co–first author
of the study and graduate student in
the applied physics program at Rice’s
Smalley-Curl Institute. “This means that
we can detect biomolecules and contam-
inants with much greater sensitivity than
before.”
The real-world applications for this
technology are vast, and the research
team successfully demonstrated a minia-
turized version of the system on a single
glass slide, proving that the technique
is scalable and can be used in portable
biosensors.
One of the most promising appli-
cations is arsenite detection—a critical
need in water safety. The team
engineered E. coli bacteria with an
arsenite-responsive extracellular elec-
tron transfer pathway, enabling them
to detect the presence of arsenite at
concentrations as low as 0.1 micromoles
per liter with a clear, measurable response
from the OECT-amplified signal.
Beyond environmental applications,
the system could revolutionize wearable
health monitoring, where power-efficient
and highly sensitive biosensors are in
high demand. For example, lactate
sensing in sweat, which is an indicator of
muscle fatigue, was successfully demon-
strated using microbial fuel cells.
“Athletes, medical patients, and even
soldiers could benefit from real-time
metabolic monitoring without the need
for complex, high-power electronics,”
said co–first author Xu Zhang, a post-
doctoral fellow in the Department of
Biosciences.
The researchers emphasized that
understanding the power dynamics
between OECTs and fuel cells is key to
optimizing sensor performance, identi-
fying two distinct operational modes. In
the power-mismatched mode, the fuel
cell generates less power than the OECT
requires, leading to higher sensitivity but
operating closer to short-circuit condi-
tions. In contrast, the power-matched
mode occurs when the fuel cell produces
sufficient power to drive the OECT,
resulting in more stable and accurate
readings.
“By fine-tuning these interactions, we
can design sensors tailored for different
applications, from highly sensitive
medical diagnostics to robust environ-
mental monitors,” Verduzco said. “We
INDUSTRYNEWS
|
SCANNER
ASNT AND AWS
FORMALIZE
COLLABORATION TO
EXPAND IN INDIA
In March, the American Society for
Nondestructive Testing (ASNT) and the
American Welding Society (AWS) announced
the signing of a program agreement formal-
izing their collaboration to expand, develop,
and implement training and certification
activities for welding and nondestructive
testing (NDT) professionals in India and
the Middle East region. This agreement
solidifies both organizations’ commitment
to address the growing demand for skilled
professionals in these critical industries.
This partnership will leverage the
strengths of both organizations to provide
world-class training and certification oppor-
tunities. A key element of the agreement is
reciprocal access to each other’s authorized
training and certification facilities. This will
enable ASNT and AWS to conduct qualifi-
cation and certification training and exam-
ination services at each other’s approved
locations, significantly increasing accessi-
bility for professionals seeking to advance
their careers.
ASNT, through its subsidiary ASNT
India, operates a facility in Chennai, India,
providing NDT education and certification.
This existing presence, combined with
AWS’s expertise in welding education and
certification, creates a powerful synergy for
expanding, developing, and implementing
a wide range of training and certification
activities for welding and NDT professionals
in India and the Middle East.
ASNT and AWS will also establish a new
training and certification center in Gujarat,
India. This strategically located facility
will serve as a hub for program activities,
providing state-of-the-art training and
examination resources to individuals and
organizations in the region.
|
SOCIETYNOTES
The Rice University research team that developed a new method to dramatically enhance the
sensitivity of enzymatic and microbial fuel cells using OECTs (from left to right): Rafael Verduzco,
Ravindra Saxena, Caroline Ajo-Franklin, and Xu Zhang.
A P R I L 2 0 2 5 • M AT E R I A L S E V A L U AT I O N 9
CREDIT:
RICE
UNIVERSITY
OFFICE
OF
PUBLIC
AFFAIRS

believe this approach will change how
we think about bioelectronic sensing. It’s
a simple, effective, and scalable solution.”
This research was sponsored by the
Army Research Office, CPRIT, and the
National Science Foundation.
SQUID-INSPIRED
FLEXIBLE SCREEN
STORES AND DISPLAYS
ENCRYPTED IMAGES
WITHOUT ELECTRONICS
A flexible screen, inspired in part by
squid, can store and display encrypted
images like a computer—using magnetic
fields instead of electronics. Researchers
from the University of Michigan (UM)
recently reported the innovation in
Advanced Materials.
“It’s one of the first times where
mechanical materials use magnetic fields
for system-level encryption, information
processing, and computing. And unlike
some earlier mechanical computers,
this device can wrap around your
wrist,” said Joerg Lahann, the Wolfgang
Pauli Collegiate Professor of Chemical
Engineering and co-corresponding
author of the study.
The innovative screen could be
applied in scenarios where light or power
sources are impractical, including with
clothing, stickers, ID badges, barcodes,
and ebook readers. It displays a public
image when near a regular magnet and a
private, encrypted one when placed over
a complex array of magnets that func-
tions as an encryption key.
“This device can be programmed to
show specific information only when
the right keys are provided. And there
is no code or electronics to be hacked,”
said Abdon Pena-Francesch, UM assis-
tant professor of materials science and
engineering and co-corresponding
author. “This could also be used for
color-changing surfaces—for example, on
camouflaged robots.”
Shaking the screen erases its display,
similar to an Etch-A-Sketch, but the image
is encoded in the magnetic properties
of beads inside the screen. It reappears
when exposed to the magnetic field
again.
The beads function like pixels,
switching between orange and white
hemispheres. Magnetic particles within
the beads enable them to rotate,
providing color contrast. A weak
magnetic field can reprogram pixels
made with iron oxide particles, while
those with neodymium require a stronger
magnetic pulse.
By holding the screen over a grid of
magnets with varying strengths and
orientations, the pixels’ polarization can
be selectively changed, encoding an
image. Private images can be displayed
by using a second magnetic grid that
reprograms certain pixels, while the
public image remains accessible under a
standard magnet.
Multiple private images can be gener-
ated from a single public image, each
requiring a unique key. The decoding
keys can also be programmed to only
work with specific encoding keys, for
extra security.
The researchers designed the screen’s
resolution by studying squids and octo-
puses, which change color by expanding
and contracting pigment sacs in their skin.
“If you make the beads too small, the
changes in color become too small to
see,” said Zane Zhang, a UM doctoral
student and the study’s first author. “The
squid’s pigment sacs have optimized size
and distribution to give high contrast, so
we adapted our device’s pixels to match
their size.”
The research was funded by the
American Chemical Society Petroleum
Research Fund and the National Science
Foundation. An invention disclosure has
been filed with the assistance of UM
Innovation Partnerships. Jeffery Raymond
is a co-author of the study, along with
Zhang, Lahann, and Pena-Francesch. The
paper can be accessed at https://doi.
org/10.1002/adma.202406149.
TRIGO ACQUIRES
CONTROREUPE TO
BOLSTER AEROSPACE
AND DEFENSE QUALITY
CONTROL CAPABILITIES
TRIGO announced the acquisition of
Controreupe, a specialized nonde-
structive testing (NDT) company based
in Saint-Geneviève-des-Bois, France,
on 16 January 2025. This acquisition
strengthens TRIGO’s position in the
industrial quality control market and
expands its service portfolio in the aero-
space and defense sectors. Controreupe
specializes in penetrant testing and 3D
measurement of complex parts.
With 30 years of expertise,
Controreupe generates annual revenues
of €3 million (US$3.12 million) from NDT.
The acquisition is a key step in TRIGO’s
strategic plan to expand its component
inspection, control, and testing solutions.
This initiative follows the recent achieve-
ment of TRIGO’s Aerospace, Defense,
SCANNER
|
INDUSTRYNEWS
The palm-sized, transparent square screen contains orange and white beads, roughly the size of
sand grains, arranged in a smaller square inside. By holding the screen near magnets of varying
strengths, the magnetic properties of specific pixels can be altered, allowing different magnet
arrays to program different images. When held over a magnet, the magnetic pixels in the screen
flip to display the University of Michigan block M.
10
M AT E R I A L S E V A L U AT I O N • A P R I L 2 0 2 5
CREDIT:
JEREMY
LITTLE/MICHIGAN
ENGINEERING