Medical Design Briefs - May 2021 - 26

Low-Voltage, Low-Power Pressure
Sensors Monitor Health
There has been little exploration of the
use of organic electrochemical transistors
(OECTs) in pressure sensors because
Ionic hydrogels with tiny
OECTs are usually paired with liquid gatpyramidal microstructures help to increase
ing substances, which do not respond well
the pressure sensitivity
to external pressure. A team has found
that can be measured.
ways to solve this problem.
(Credit: Terasaki Institute)
They first experimented with a solid
type of gating substance - a charged, gelatinous substance called
an ionic hydrogel. Due to the physical characteristics of this gel, they
were able to demonstrate improved pressure sensing when they
used it together with OECTs. The team fabricated ionic hydrogels
with tiny pyramidal microstructures, which helped to increase the
pressure sensitivity that could be measured. The deformity of the
hydrogel microstructures in response to applied pressure increases the capacitance change at the gate electrodes, enhancing the
ability to detect very subtle pressure signals.
The team also found that the microstructured hydrogel
allowed them to obtain higher pressure sensitivity that could be
adjusted by changing the applied gate voltage. Furthermore,
this optimized sensor could operate at low operation voltage
and low power consumption. These features combine to make
a high-performing pressure sensor that is economical, longlasting, and energy efficient - clear advantages for devices that
are intended to collect long-term, real-time data.
For more information, visit www.medicaldesignbriefs.com/
roundup/0521/pressure.

Microcomb Could Detect
Diseases
Tiny photonic devices
could be used to monitor a
person's health. Researchers
have created a microcomb
The chip and experimental setup
that could bring advanced
for generating the microcomb.
applications closer to reality. A
(Credit: Mia Halleröd Palmgren/
Yen Strandqvist/Chalmers)
microcomb is a photonic device
capable of generating a myriad of optical frequencies - colors - on a tiny cavity known as
microresonator. These colors are uniformly distributed so that the
microcomb behaves like a ruler made of light. The device can be
used to measure or generate frequencies with extreme precision.
The new kind of microcomb on a chip is based on two
microresonators. The new microcomb is a coherent, tunable,
and reproducible device with up to 10 times higher net conversion efficiency than the current state of the art.
The researchers are not the first to demonstrate a microcomb
on a chip, but they have developed a method that overcomes several well-known limitations in the field. The key factor is the use
of two optical cavities - microresonators - instead of one. This
arrangement results in the unique physical characteristics.
Placed on a chip, the newly developed microcomb is so small
that it would fit on the end of a human hair. The gaps between
the teeth of the comb are very wide, which opens great opportunities for both researchers and engineers.
For more information, visit www.medicaldesignbriefs.com/
roundup/0521/microcomb.

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Medical Design Briefs, May 2021

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Medical Design Briefs - May 2021

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