Medical Design Briefs - November 2022 - 27

n Thermoresponsive
Smart Materials
A thermoresponsive polymer can be
regulated by changing the type and
mixing ratio of ionic species. (Credit:
Osaka Metropolitan University)
Scientists have developed
a novel polymer, the thermoresponsiveness
of which can
easily be regulated by changing
the type and mixing ratio
of ionic species. The researchers
used water as the solvent
and developed an LCST-type
thermoresponsive polymer by
adding alkaline earth metal ions - which are divalent cations
- to polymers and aqueous solutions.
In LCST-type thermoresponsive polymers, as the temperature
increases, the polymer-solvent interaction decreases and
the polymer-polymer interaction becomes dominant, leading
to precipitation of polymers from the solvent.
The team succeeded in regulating thermoresponsive properties,
simply by changing the species and mixing ratio of the
ions. This is different from the conventional technique that
can only regulate thermoresponsiveness by changing the structure
of the polymers.
The researchers expect that the polymer will be applied as an
analytical reagent for metal ion-sensing devices and as a material
for drug-delivery systems.
For more information, visit www.medicaldesignbriefs.com/
roundup/1122/thermo.
n Pulsed MRI System
Could Selectively Deliver
Drugs to the Brain
Researchers have demonstrated the
A new type of MRI could be
used to generate tailored
electromagnetic waveforms.
(Credit: Pixabay/kalhh)
ability to open the blood-brain barrier
(BBB) in mice and to safely deliver
drugs using pulsed magnetic fields
with tailored waveforms. This work
spurs development of a new class of
noninvasive image-guided devices capable
of safely treating many mental
health and neurological disorders.
The new type of MRI - composed
of electro-permanent magnets - could be used to generate
tailored electromagnetic waveforms, some of which were
much more effective at opening the BBB than others. As in a
CT scanner, the selective electromagnetic waveforms could be
applied from multiple sources to focally deliver drugs to specific
regions of the brain.
The same device could also use magnetic pulses to help regrow
neurons (plasticity), as is being done with transcranial magnetic
stimulation (TMS). The new device would allow psychiatrists
and neurologists to treat diseased or underdeveloped brain
tracts without causing unwanted side effects. Potential disorders
to be treated could include addiction, autism, depression, neuropathic
pain, and Alzheimer's and Parkinson diseases.
Using an office-based human-sized version of this non-invasive
device, it may prove possible to cure Alzheimer's by delivering
drugs and genes to specified tracts in the brain under
real-time imaging guidance.
For more information, visit www.medicaldesignbriefs.com/
roundup/1122/brain.
Medical Design Briefs, November 2022
The three-core optical fiber sensor for measuring
spine curvature. Credit: Optical Engineering,
doi 10.1117/1.OE.61.9.097102.
n Optical Fiber
Sensor Measures
Deviations in Spine
A new type of sensor
based on optical fibers
offers advantages,
and
small
size. The sensors have
already been used to monitor the curvature of structures and robotic
arms. But measuring both the magnitude and direction of
the spine's curvature presents an additional challenge - one that
the team overcame through innovative design.
In the proposed optical fiber sensor, input of light travels
through three fiber cores. The operating principle of the sensor
is based on the concept of what is called wavelength modulation.
When an optical fiber is bent, the structure of the
fiber core's material changes, altering its density. In turn, this
modifies the refractive index of the core, and the wavelength
of the output light changes depending on how much the fiber
was bent.
By constructing calibration tables, the magnitude of the spine's
curvature can be estimated based on the difference between the
wavelengths of the input and output light in a single core.
One significant advantage of the fiber is that it shows linear results
in the output. The new optical fiber sensor could pave the
way for a new method of measuring the curvature of the different
sections of the spine.
For more information, visit www.medicaldesignbriefs.com/
roundup/1122/sensor.
n Stable Electrodes for
Long-Term BCI
This electrode can be worn comfortably
and stable for up to four weeks.
(Credit: University of Texas at Austin)
Researchers at have developed
an electroencefalography
(EEG) electrode that
patients wear on their head
to monitor brain activity. The
EEG electrodes system could
act as a brain-computer interface
(BCI), which can be
controlled by brain signals to help repair damage to the brain
caused by strokes and other disorders.
The electrode can be worn comfortably and stable for up to
four weeks, without the potential need for any medical personnel
to intervene to maintain it. This is a big improvement on
currently available electrodes that typically need to be replaced
every few hours or days at best.
The new electrode has the benefits of a wet, gel-based electrode,
and eliminates major drawbacks, such as their tendency
to dry out and then fall off. The project builds on a promising
solution in early research phases that involves using conductive
polymers as the basis for the electrodes.
The researchers used conductive polymers together with polymers
with high water content. That allows them to take advantage
of the benefits of gel-based materials, primarily that they can give
accurate recordings despite interference caused by the skin and
hair, a concept known as electrode-skin impedance.
For more information, visit www.medicaldesignbriefs.com/
roundup/1122/electrodes.
www.medicaldesignbriefs.com
27
including
low cost, high
sensitivity,
http://www.medicaldesignbriefs.com/roundup/1122/thermo http://www.medicaldesignbriefs.com/roundup/1122/sensor http://www.medicaldesignbriefs.com/roundup/1122/brain http://www.medicaldesignbriefs.com/roundup/1122/electrodes http://www.medicaldesignbriefs.com
Medical Design Briefs - November 2022

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