Tech Briefs Magazine - August 2023 - 30

Health & Biotech
Since the patch is simple to use, it
could solve these problems, said
Sai
Zhou, a materials science and engineering
PhD student at UC San Diego and
co-author of the study. " Just stick it on
the skin, then read the signals. It's not
operator dependent, and it poses no extra
work or burden to the technicians,
clinicians or patients, " he said.
In tests, the patch performed as well as
The patch is made up of a thin sheet of flexible, stretchable polymer that adheres to the skin.
(Image: Nature Biomedical Engineering)
The phased array consists of a 12 × 12
grid of ultrasound transducers. When
electricity flows through the transducers,
they vibrate and emit ultrasound waves
that travel through the skin and deep into
the body. When the ultrasound waves
penetrate through a major blood vessel,
they encounter movement from red
blood cells flowing inside. This movement
changes or shifts how the ultrasound
waves echo back to the patch . This
shift in the reflected signals gets picked
up by the patch and is used to create a visual
recording of the blood flow. This
same mechanism can also be used to create
moving images of the heart's walls.
The standard blood flow exam itself can
be time consuming and labor intensive. A
trained technician presses a handheld ultrasound
probe against a patient's skin and
moves it from one area to another until it's
directly above a major blood vessel. This
may sound straightforward, but results can
vary between tests and technicians.
a commercial ultrasound probe used in
the clinic. It accurately recorded blood
flow in major blood vessels such as the
carotid artery, which is an artery in the
neck that supplies blood to the brain.
Having the ability to monitor changes in
this flow could, for example, help identify
if a person is at risk for stroke well before
the onset of symptoms.
The researchers point out that the
patch still has a long way to go before it is
ready for the clinic. Currently, it needs to
be connected to a power source and
benchtop machine in order to work. Xu's
team is working on integrating all the electronics
on the patch to make it wireless.
For more information, contact Daniel
Kane at dbkane@ucsd.edu; 858-534-3262.
An Ultrasound Patch for Non-Invasive Deep Tissue
Monitoring
The wearable device could effectively measure tissue stiffness and help treat cancer, sports
injuries, and more.
University of California San Diego, CA
A
team of engineers at the University of
California San Diego has developed a
stretchable ultrasonic array capable of serial,
non-invasive, three-dimensional imaging
of tissues as deep as four centimeters
below the surface of human skin, at a spatial
resolution of 0.5 mm. This new method
provides a non-invasive, longer-term alternative
to current methods, with improved
penetration depth.
The research emerges from the lab of
Sheng Xu, a Professor of Nanoengineering
at UC San Diego Jacobs School of Engineering
and corresponding author of
the study. " We invented a wearable device
that can frequently evaluate the stiffness of
human tissue, " said Hongjie Hu, a Postdoctoral
Researcher in the Xu group and
study coauthor. " In particular, we integrated
an array of ultrasound elements into a
soft elastomer matrix and used wavy serpentine
stretchable electrodes to connect
these elements, enabling the device to
30
Optical images of the devices when twisted and stretched, showing its mechanical compliance and
robustness, and conforming to the lateral shoulder joint and neck for tissue stiffness monitoring.
(Image: UC San Diego Jacobs School of Engineering)
conform to human skin for serial assessment
of tissue stiffness. "
The elastography monitoring system
can provide serial, non-invasive and
three-dimensional mapping of mechanical
properties for deep tissues. This has
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several key applications including in
medical research, serial data on pathological
tissues can provide crucial information
on the progression of diseases
such as cancer, which normally causes
cells to stiffen as well as monitoring
Tech Briefs, August 2023

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Tech Briefs Magazine - August 2023

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