April 2025
Volume 83 • Number 4
JOURNAL STAFF
PUBLISHER: Neal J. Couture, CAE
DIRECTOR OF PUBLICATIONS/
EDITOR: Jill Ross
ASSOCIATE EDITOR:
Stefanie Laufersweiler
PRODUCTION MANAGER: Joy Grimm
DIGITAL PUBLISHING MANAGER:
Synthia Jester
DIGITAL CONTENT STRATEGIST:
Haley Cowans
ASNT MEDIA &EVENT SALES
Peter Roy, proy@asnt.org
1-614-384-2431
Sonny Hines, shines@asnt.org
1-614-384-2434
TECHNICAL EDITOR
John Z. Chen, KBR
ASSOCIATE TECHNICAL EDITORS
John C. Aldrin, Computational Tools
Sreenivas Alampalli, Stantec
Ali Abdul-Aziz, Kent State University
Yiming Deng, Michigan
State University
Dave Farson, Ohio State University
Jin-Yeon Kim, Georgia
Institute of Technology
Mani Mina, Iowa State University
Ehsan Dehghan-Niri,
Arizona State University
Yi-Cheng (Peter) Pan, Emerson Inc.
Anish Poudel, MxV Rail
Donald J. Roth, Roth
Technical Consulting LLC
Ram P. Samy, Consultant
Steven M. Shepard,
Thermal Wave Imaging
Ripi Singh, Inspiring Next
Surendra Singh, Honeywell
Roderic K. Stanley, NDE
Information Consultants
Matthew Webster, NASA
Langley Research Center
Lianxiang Yang, Oakland University
Reza Zoughi, Iowa State University
CONTRIBUTING EDITORS
Toni Bailey, TB3NDT Consulting
Bruce G. Crouse, Inspection Services
Huidong Gao, PEMEX Deer Park
Saptarshi Mukherjee, Lawrence
Livermore National Laboratory
Hossein Taheri, Georgia
Southern University
UPFRONT
|
SCANNER
FROM NATURE TO NDT
It has been over 15 years since I began my journey in nondestructive
testing (NDT). In 2010, I started my PhD at the University at Buffalo, focusing
on distributed sensor networks using guided ultrasound waves for struc-
tural health monitoring of pipelines and plate-like structures. Later, I joined
General Electric (GE) in power system production, where I expanded my
expertise in NDT. Working on composite material inspection, gas and
steam turbine components, and in-service inspections across GE Power,
Oil &Gas, and Aviation significantly enhanced my understanding of real-
world NDT applications. Now, as an associate professor in the School of
Manufacturing Systems and Networks at Arizona State University, I strive to
transfer this industry experience to my students.
In 2017, I developed and taught an NDT course at New Mexico State
University. I worked with students from civil, mechanical, industrial, and
electrical engineering departments, creating an interdisciplinary learning
environment. Securing funding to establish my research program was
a challenge, motivating me to explore innovative ideas. In 2018, while
watching a documentary [1] about aye-ayes with my then 4-year-old (and
equally curious) son Daniel, I was captivated by their unique foraging
behavior called “percussive foraging” or “tap-testing.” I immediately recog-
nized the similarity between this and conventional tap-testing techniques
used in NDT to identify hidden defects in materials. That night, I delved into
the scientific literature on aye-ayes and learned more about how they natu-
rally perform a process identical to what we do in NDT—using tapping tech-
niques to detect cavities beneath the surface. However, unlike conventional
NDT applied to engineered materials, aye-ayes detect deep cavities in far
more complex natural structures, such as tree bark, with astonishing preci-
sion. This sparked my long-term research interest in bioinspired NDT.
Supported by the National Science Foundation [2], our research has
uncovered key factors influencing the unique NDT process that aye-ayes
use in their foraging behavior. While bioinspired research has signifi-
cantly advanced fields such as robotics, materials science, and biology,
a new frontier lies in examining entire biological processes—such as
food foraging—as a model for detection, localization, sizing, and classi-
fication, much like the fundamental principles of NDT. By studying and
mimicking these natural processes, we have the potential to pioneer new
NDT methods or enhance existing techniques with greater sensitivity and
reliability.
I am honored to be the guest editor of this special issue dedicated to
the emerging field of bioinspired NDT, with the hope that this innovative
approach to engineering solutions will drive advancements in inspection
technologies, ensuring greater safety and reliability for our communities.
EHSAN DEHGHAN-NIRI, PHD
ARIZONA STATE UNIVERSITY
NDE@ASU.EDU
REFERENCES
1. “The Demon Primate.” World’s Weirdest. Aired 22 March 2012
on National Geographic Wild Network. https://youtu.be/Fw2DtZY
JuiI?si=67Z5ZmCUvu85V7EC.
2. NSF Career Award, Grant No. 2320815.
By studying
and mimicking
these natural
processes, we
have the potential
to pioneer new
NDT methods or
enhance existing
techniques with
greater sensitivity
and reliability.
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 7

RESEARCHERS
DEVELOP
NEW METHOD
TO AMPLIFY
BIOELECTRONIC
SENSING
In a breakthrough that could transform bioelectronic
sensing, an interdisciplinary team of researchers at
Rice University (Houston, TX) has developed a new
method to dramatically enhance the sensitivity of
enzymatic and microbial fuel cells using organic
electrochemical transistors (OECTs). The research
was recently published in the journal Device.
The innovative approach amplifies electrical
signals by three orders of magnitude and improves
signal-to-noise ratios, potentially enabling the next
generation of highly sensitive, low-power biosensors
for health and environmental monitoring.
“We have demonstrated a simple yet powerful
technique to amplify weak bioelectronic signals
using OECTs, overcoming previous challenges in
integrating fuel cells with electrochemical sensors,”
said corresponding author Rafael Verduzco,
professor of chemical and biomolecular engineering
and materials science and nanoengineering. “This
method opens the door to more versatile and effi-
cient biosensors that could be applied in medicine,
environmental monitoring, and even wearable
technology.”
Traditional biosensors rely on direct interactions
between target biomolecules and the sensor device,
which can pose limitations when the electrolyte envi-
ronment is incompatible. This research circumvents
that challenge by electronically coupling fuel cells
with OECTs instead of introducing biomolecules
directly into the sensor.
“One of the biggest hurdles in bioelectronic
sensing has been designing systems that work in
different chemical environments without compro-
mising performance,” said corresponding author
Caroline Ajo-Franklin, professor of biosciences,
director of the Rice Synthetic Biology Institute, and
Cancer Prevention and Research Institute of Texas
(CPRIT) Scholar. “By keeping the OECT and fuel cell
separate, we ensured optimal conditions for both
components while still achieving powerful signal
amplification.”
OECTs are thin-film transistors that operate in
aqueous environments and have gained attention
for their high sensitivity and low-voltage operation.
For the study, the team integrated OECTs with two
types of biofuel cells to enhance their performance.
The first type, enzymatic fuel cells, utilize glucose
dehydrogenase to catalyze glucose oxidation, gener-
ating electricity in the process. The second type,
microbial fuel cells, rely on electroactive bacteria to
metabolize organic substrates and produce current.
The OECTs were coupled with the fuel cells in two
different configurations: a cathode-gate configura-
tion and an anode-gate configuration.
The researchers found that OECTs can amplify
signals from enzymatic and microbial fuel cells by
factors ranging from 1000 to 7000, depending on
the configuration and fuel cell type. This amplifica-
tion is significantly higher than traditional electro-
chemical amplification techniques, which typically
achieve signal enhancements in the range of 10 to
100 stronger.
The team discovered that the cathode-gate
configuration provided the best amplification, espe-
cially when using a specific polymer as the channel
material. The anode-gate configuration also showed
strong amplification but posed potential challenges
at higher fuel cell currents, leading to irreversible
degradation in some cases.
Along with boosting signal strength, the
researchers found that OECTs reduced back-
ground noise, making measurements more precise.
Traditional sensors can struggle with interference
and weak signals, but the OECTs produced clearer,
more reliable data.
SCANNER
A lithographically patterned
organic electrochemical
transistor (OECT) device, used for
measurement with enzymatic
and microbial fuel cells.
Researchers at Rice University
are using OECTs to amplify weak
bioelectronic signals.
8
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:
RICE
UNIVERSITY
OFFICE
OF
PUBLIC
AFFAIRS