Tech Briefs Magazine - September 2021 - 35

Sensors
Graphite-Based Sensor for Wearable Medical Devices
Putty-based inks are printed as a thin film onto elastic substrates and attached to the skin.
Trinity College Dublin, University of Dublin, Ireland
esearchers have developed graphenebased
sensing technology using GPutty
material - a highly malleable
graphene blended putty. The printed
sensors are 50 times more sensitive than
the industry standard and outperform
other comparable nano-enabled sensors
in an important metric: flexibility.
Maximizing sensitivity and flexibility
without reducing performance makes
the technology an ideal candidate for
the emerging areas of wearable electronics
and medical diagnostic devices.
The team demonstrated that it can
produce a low-cost, printed, graphene
nanocomposite strain sensor. Creating
and testing inks of different viscosities
(runniness), the team found it could tailor
G-Putty inks according to printing
technology and application. In medical
settings, strain sensors are a valuable di -
R
agnostic tool used to measure changes
in mechanical strain, such as pulse rate,
or changes in a stroke victim's ability to
swallow. A strain sensor works by detecting
this mechanical change and converting
it into a proportional electrical
signal, thereby acting as mechanicalelectrical
converter. While strain sensors
are currently available, they are mostly
made from metal foil that poses limitations
in terms of wearability, versatility,
and sensitivity.
The team turned G-putty into an ink
blend that has excellent mechanical and
electrical properties. The inks can be
turned into a working device using in -
dustrial printing methods, from screen
printing to aerosol and mechanical deposition.
An additional benefit is that the
team can control a variety of different
parameters during the manufacturing
process, which provides the ability to
tune the sensitivity of the material for
specific applications calling for detection
of minute strains.
The development of the sensors represents
a considerable step forward in wearable
diagnostic devices - devices that
can be printed in custom patterns and
comfortably mounted to a patient's skin
to monitor a range of different biological
processes. The team is exploring applications
to monitor real-time breathing and
pulse, joint motion and gait, and early
labor in pregnancy. Because the sensors
combine high sensitivity, stability, and a
large sensing range with the ability to
print bespoke patterns onto flexible,
wearable substrates, the team can tailor
the sensor to the application.
For more information, contact Thomas
Deane at deaneth@tcd.ie; +353 1 896 4685.
Imitating Human Hands to Make Better Sensors
This work could help severely injured people, such as soldiers, regain the ability to control
their movements.
The Pennsylvania State University, University Park
esearchers have developed " electron -
ic skin " sensors capable of mimicking
the dynamic process of human
motion. They attempted to imitate the
biological and dynamic process of the
skin of the human hand to enable
objects to behave similarly.
The dual-mode sensor measures both
the magnitude and load of movement
- such as the effort of swinging a tennis
racquet - as well as rate, duration,
and direction. The trick was to decouple
this measurement and understand
how the separate parameters influence
each other; for example, bouncing a
tennis ball gently on a racquet requires
different input than serving a ball to an
opponent. Those same variables come
into play when a person with a prosthetic
arm needs to differentiate be -
tween handling an egg or carrying a
watermelon.
R
Tech Briefs, September 2021
Cov
A dual-mode sensor functions as electronic skin to measure the dynamic nature of human motion.
(Image: Cheng Laboratory/Ye Qiu)
www.techbriefs.com
ToC
35

http://www.techbriefs.com http://www.abpi.net/ntbpdfclicks/l.php?202109TBNAV

Tech Briefs Magazine - September 2021

Table of Contents for the Digital Edition of Tech Briefs Magazine - September 2021