Medical Design Briefs - November 2023 - 25

n Wearable Detects Stress
Hormone 24 Hours
Early warning signs of diseases
caused by dysfunctional levels
of stress hormones could be
spotted more easily thanks to a
new wearable device developed
n Minimally Invasive Smart
Glaucoma Implants
A minimally invasive and smart
glaucoma implant has the potential
to decrease the incidence of postoperative
complications. The biodegradable
glaucoma implant is
by endocrine researchers. This is the first time it has been possible
to measure changes to people's stress hormones as they go
about normal daily activities, across both day and night.
The wearable device is worn around the waist and painlessly
and automatically samples from beneath the skin every 20 minutes,
without the need to collect blood. Importantly, the method
allows sampling during sleep, work, and other daily life activities
for up to 72 hours in a single session.
The technology, funded by an EU Horizon 2020 project grant,
shows how tracking adrenal steroid levels at high resolution and
over an extended time period can provide better information
about how hormone levels change across daily (circadian) and
faster (ultradian) time periods. (Image credit: EPFL)
For more information, visit www.medicaldesignbriefs.com/
roundup/1123/stress.
n AI-Enabled Sensor Offers
Holistic Wound Monitoring
An innovative sensor patch
provides a simple, convenient,
and effective way of monitoring
wound recovery so that clinical
intervention can be triggered
in a timely manner to improve
wound care and management.
The PETAL (Paper-like Battery-free In situ AI-enabled
Multi plexed) sensor patch comprises of five colorimetric sensors
that can determine the patient's wound healing status
within 15 minutes by measuring a combination of biomarkers
- temperature, pH, trimethylamine, uric acid, and moisture
of the wound. These biomarkers were carefully selected to effectively
assess wound inflammation and infection as well as
the condition of the wound environment.
The patch operates without an energy source - sensor images
are captured by a mobile phone and analyzed by AI algorithms
to determine the patient's healing status. Each PETAL
sensor patch consists of a fluidic panel patterned in the form of
a five-petal pinwheel flower, with each 'petal' acting as a sensing
region. An opening in the center of the fluidic panel collects
fluid from wound and distributes the fluid evenly via five
sampling channels to the sensing regions for analysis. Each
sensing region uses a different color-changing chemical to detect
and measure the respective wound indicators.
The fluidic panel is sandwiched between two thin films. The
top transparent silicone layer allows for normal skin functions
of oxygen and moisture exchange, and it also enables image
display for accurate image capture and analysis. The bottom
wound contact layer gently attaches the sensor patch to the
skin and protects the wound bed from direct contact with the
sensor panel, to minimize wound tissue disruptions. (Image
credit: National University of Singapore)
For more information, visit www.medicaldesignbriefs.com/
roundup/1123/wound.
Medical Design Briefs, November 2023
approximately the same size as the world's smallest medical device
known to be implanted in the human body,
One option is a magnetically actuated glaucoma implant that
can be noninvasively and repeatedly adjusted to different intraocular
pressure (IOP) conditions even after implantation. Adjustment
is achieved by integrating a magnetic microvalve in
the implant, which can open or close fluidic channels, and thus
change the hydro dynamic resistance of the implant when
needed, and all by using a simple external magnet.
Another option is biodegradable. The implant will slowly degrade
and then be absorbed by the body over time, leaving behind
a natural pathway for fluid drainage. It can be placed at a
location in the eye with far less tissue dissection required, all
while still fulfilling the main purpose of removing excess fluid
from the eye and decreasing intraocular pressure.
Both the magnetic-based and biodegradable polymer-based implants
could be safer and more effective when it comes to reducing
IOP than current devices on the market. In addition, the implants
can halt the progression of glaucoma and related visual field loss,
enhancing the quality of life of glaucoma patients. (Image credit:
Eindhoven University of Technology)
For more information, visit www.medicaldesignbriefs.com/
roundup/1123/implants.
n Wearable Sensor Makes
Continuous Analysis of
Sweat Possible
Made with a laser-modified
graphene nanocomposite material,
a wearable device can detect
specific glucose levels in sweat for three weeks while simultaneously
monitoring body temperature and pH levels.
Working at the nanoscale, the researchers reported using a
simple laser treatment to create a stable, 3D network of highly
conductive noble metal alloys - gold and silver in this case -
and carbon-based nanocomposite materials on the porous
laser- induced graphene (LIG) electrode. Noble metals are not
only highly conductive but are also resistant to oxidation.
In addition to measuring glucose, the modified LIG electrode
responded to changes in pH levels, too, according to the researchers.
To fabricate the wearable device, they combined the dual glucose
and pH sensor with another LIG-based temperature sensor
and a stretchable layer with coil-shaped microfluidic channels to
continuously collect and route sweat for sampling.
The device allows for the calibration of glucose measurements
based on fluctuations in sweat pH and body temperature from activities
such as exercise and eating. Worn as a patch roughly twice
the width of a postage stamp and affixed to the skin with adhesive
tape, it can wirelessly communicate its collected data to a computer
or mobile device for real-time monitoring and analysis. (Image
credit: Kate Myers/Penn State)
For more information, visit www.medicaldesignbriefs.com/
roundup/1123/sweat.
www.medicaldesignbriefs.com
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Medical Design Briefs - November 2023

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