Medical Design Briefs - July 2021 - 22

The shellfish play a valuable
role by demonstrating how
they make adhesives. (Credit:
Purdue University/Rebecca
McElhoe)
Studying Shellfish Helps
Develop New Adhesives
Chemists are studying shellfish to
develop new, safer, and more sustainable
adhesives for a variety of
uses, including bandages and other
medical applications. They are
looking at how shellfish create
materials, what components of the
adhesives are playing active roles in
bonding, and testing new synthetic
and biomimetic glues to determine their efficacy, feasibility,
and performance. They are building on that understanding to
develop adhesives that work underwater, are stronger, more
sustainable, made from food products, and that can be unstuck
when needed.
The researchers are making adhesives with new functionalities
by adding in new chemical groups to target all sorts of
properties, be that wet bonding, rubber-like flexibility, or the
ability to bond and then de-bond. One of their systems can
even be stronger than what the animals make underwater. In
that case, they are using chemistry that is inspired by the shellfish
but, overall, the system is a simplification of what the animals
produce.
Increasing the sustainability and the functionality of adhesives
can improve human life in a myriad of ways: by limiting
exposure to harmful chemicals, by making healing more comfortable,
and by making products more sustainable and more
recyclable to preserve resources and the planet.
For more information, visit www.medicaldesignbriefs.com/
roundup/0721/shellfish.
Antimicrobial Surface Reduces
Bacteria Buildup on Medical
Instruments
A 3D antimicrobial surface
reduces bacteria buildup
on medical equipment, like
urinary catheters. (Credit:
Monash University)
Researchers have engineered new
antimicrobial surfaces that can significantly
reduce the formation of bacteria
on medical instruments, such as
urinary catheters, and reduce the risk
of patient infection while in hospital.
This study demonstrates the potential
for 3D engineered surfaces in preventing the initial formation
of microcolonies of Escherichiacoli (E.coli), Klebsiellapneumoniae,
and Pseudomonas aeruginosa - the three most common urinary
tract bacterial infections (UTIs) associated with catheters.
Through an extensive screening process, researchers identified
that the sharp corners of the vertical side walls within the
conventional micropatterned surfaces gifted bacteria with perfect
hiding spots to shelter themselves against the flow of fluids
which could wash them away.
Their 3D engineered microtopographies with varying
heights and smooth curved cross- sections can simultaneously
deter both the initial attachment and the formation of biofilms
for three clinically relevant bacteria. The researchers hypothesize
that by smoothing out these corners, the bacteria would be
left with nowhere to hide.
For more information, visit www.medicaldesignbriefs.com/
roundup/0721/antimicrobial.
22
Intro
Cov
A sensor provides continuous
detection of cortisol concentrations
in real time. (Credit:
Talanta, April 2021)
The concept of energy harvesting
with flexible thermoelectrics shown
with a schematic of aerosol jet printing.
(Credit: Injung Le)
Nontoxic, Flexible Energy
Converters Could Power
Wearable Devices
Researchers report the
design and fabrication of
single-wall carbon nanotube
thermoelectric devices on
flexible polyimide substrates
as a basis for wearable energy
converters.
Carbon nanotubes
are
one-dimensional materials, known for good thermoelectric
properties, which mean developing a voltage across them
in a temperature gradient. The researchers note that the
challenge is that carbon nanotubes also have high thermal
conductivity, meaning it's difficult to maintain a thermal
gradient across them, and they have been hard to assemble
them into thermoelectric generators at low cost. The
group uses printed carbon nanotube networks to tackle
both challenges.
Thermoelectric devices generate electric power locally by
reusing waste heat. The group's approach demonstrates a
path to using carbon nanotubes with printable electrodes
on flexible polymer substrates in a process anticipated to be
economical for large-volume manufacturing. It is also
greener than other processes, because water is used as the
solvent and additional dopants are avoided.
For more information, visit www.medicaldesignbriefs.com/
roundup/0721/energy.
Sensor Tracks Stress
Hormone in Real Time
A prototype of a fluorescencebased
sensor provides continuous
detection of cortisol concentrations
in real time, which can help
monitor various health conditions.
Researchers created a prototype
immunosensor for cortisol
monitoring using gold nanoparticles.
The free cortisol in the sample displaces fluorescently
marked complexes of cortisol and bovine serum albumin
(BSA), which are attached to monoclonal antibodies to cortisol
and put onto nanoscale gold " islands " on the sensor. The fluorescence
can be measured as a signal of cortisol concentration
in the sample.
In in vitro tests, the new sensor showed the lowest levels of
detection for cortisol of 0.02 µg/ml, comparable to normal levels
in the human plasma. The reversible response was also
demonstrated in vitro. The team hopes their approach can
lead to the development of an implantable sensor for continuous
monitoring of cortisol concentration in real time.
Such an implantable sensor will look like an optical fiber
with a capillary cell at the end covered by the semipermeable
membrane placed in a thin needle. This needle will have several
inside layers and will be connected to a portable spectrometer
via fiber optics.
For more information, visit www.medicaldesignbriefs.com/
roundup/0721/sensor.
www.medicaldesignbriefs.com
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http://www.medicaldesignbriefs.com/roundup/0721/energy http://www.medicaldesignbriefs.com/roundup/0721/shellfish http://www.medicaldesignbriefs.com/roundup/0721/antimicrobial http://www.medicaldesignbriefs.com/roundup/0721/sensor http://www.medicaldesignbriefs.com
Medical Design Briefs - July 2021

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