Medical Design Briefs - September 2021 - 32

Batteryless Pacemaker
Could Use Heart's
Energy for Power
The batteryless pacemaker harvests
kinetic energy. (Credit: Yi Zhiran)
The cardiac pacemaker of
the future could be powered
by the heart itself. Researchers
are harvesting kinetic energy
from the heart to power pacemakers.
The energy is harvested by the buckling of the encapsulated
structure of the pacemaker, creating buckled piezoelectric
energy.
The group is investigating batteryless powering and leadless
pacing, but the challenge has been to obtain sufficient power
by scavenging heart kinetic energy. The energy is harvested by
the buckling of the encapsulated structure of the pacemaker,
creating buckled piezoelectric energy. This method of power
supply varies greatly from current pacemaker designs.
The key difference is the method of the power supply. They
say a batteryless pacemaker is feasible through using implantable
energy harvesting technology, which provides a sustainable
power supply method. "
The group is working to overcome some drawbacks to the device,
such as the long-term stability in vivo, the implanting method, and
the integration between the rigid pacing chip and the flexible energy
harvesting unit, before progressing to the next steps.
For more information, visit www.medicaldesignbriefs.com/
roundup/0921/pacemaker.
Coating Releases
Antimicrobial Peptides
In a proof-of-concept study, researchers
Schematics of endotracheal
tube and
electron microscopy
images of coated
and uncoated tubes.
have created a coating that can be applied
to endotracheal tubes and release antimicrobial
peptides that target infectious bacteria
with specificity. The innovation could
reduce upper-airway bacterial inflammation
during intubation, a situation that can lead
to chronic inflammation and a condition
called subglottic stenosis, the narrowing of the
airway by an accumulation of scar tissue.
The investigators explored the use of
antimicrobial peptides (AMPs), which are small proteins that
destabilize bacterial membranes, causing bacterial cells to fall
apart and die. This mechanism of action allows them to target
specific bacteria and makes them unlikely to promote antimicrobial
resistance.
They tested their theory by creating a polymer coating that
would release Lasioglossin-III, an AMP with broad-spectrum antibacterial
activity. They found that Lasio, released from coated
endotracheal tubes, reached the expected effective concentration
rapidly and continued to release at the same concentration
for a week, which is the typical timeframe that an endotracheal is
used before being changed. The investigators also tested their
drug-eluting tube against airway microbes, including S. epidermidis,
S. pneumoniae, and human microbiome samples and ob -
served significant antibacterial activity, as well as prevention of
bacterial adherence to the tube.
For more information, visit www.medicaldesignbriefs.com/
roundup/0921/coating.
32
Intro
Cov
The team created their flexible
UV light sensors on a
semiconductor wafer 8 in. in
diameter. (Credit: NTU)
UV Sensors for Wearables
Are Flexible, Sensitive
To enable the development of
wearable devices that possess
advanced ultraviolet (UV) detection
functions, scientists have created
a new type of light sensor that
is both flexible and highly sensitive.
A wearable device, such as a Tshirt
or watch that monitors the
actual personal UV exposure throughout the day, would be a
useful and more accurate guide for people seeking to avoid
sun damage.
The flexible UV light sensors were 25 times more responsive,
and 330 times more sensitive, than existing sensors, exceeding
the performance level required for optoelectronic applications.
The team created their flexible UV light sensors on a
semiconductor wafer 8 in. in diameter, using free-standing
single-crystalline layers of GaN and aluminum gallium nitride
(AlGaN), arranged using membranes that consist of two different
thin semiconductor layers (heterostructure membranes).
Under a range of external strains (compressive, flat, and tensile),
the sensors recorded a responsivity level of between 529-
1340 A/W (unit used to measure the ability of a device to transfer
an optical signal to an electrical signal), which is about 100
times higher than existing UV sensors. This responsivity
remained stable after 100 cycles of repetitive bending, demonstrating
its potential to be integrated into wearables.
For more information, visit www.medicaldesignbriefs.com/
roundup/0921/wearables.
Tiny Wireless Device
Illuminates Neuron Activity
in the Brain
The wireless battery-free
device, which is implanted
just under the skin, is as thin
as a sheet of paper and about
half the diameter of a dime.
(Credit: University of Arizona)
Researchers are creating new
tools for a method called optogenetics,
which shines light at specific
neurons in the brain to excite or
suppress activity. Optogenetics
experiments are aimed at increasing
understanding of how the brain
works, allowing scientists to develop
and test potential cures for illnesses
such as neurodegenerative diseases.
They've demonstrated an untethered light-delivery tool to
enable seamless optogenetics in the brain - the first wireless
transcranial optogenetic simulation device that can send light
through the skull rather than physically penetrating the bloodbrain
barrier. The transcranial technique is done using a wireless
and battery-free device that's as thin as a sheet of paper and
about half the diameter of a dime, implanted just under the skin.
The breakthrough of a more powerful light delivery method
improves scientists' ability to study subjects under more natural
conditions. Because it doesn't require invasive probes, it
also makes optogenetics research more accessible. Now, even
labs without a sophisticated array of surgical equipment can
help advance the field.
For more information, visit www.medicaldesignbriefs.com/
roundup/0921/brain.
www.medicaldesignbriefs.com
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http://www.medicaldesignbriefs.com/roundup/0921/pacemaker http://www.medicaldesignbriefs.com/roundup/0921/wearables http://www.medicaldesignbriefs.com/roundup/0921/coating http://www.medicaldesignbriefs.com/roundup/0921/brain http://www.medicaldesignbriefs.com
Medical Design Briefs - September 2021

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