Tech Briefs Magazine - January 2022 - 45

A prototype facemask can diagnose the person wearing the mask with COVID-19 within about 90
minutes. The technology can also be used to design wearable sensors for a variety of other
pathogens or toxic chemicals. (Photo: Felice Frankel and MIT News Office)
First, the team performed a screen of
hundreds of different types of fabric,
from cotton and polyester to wool and
silk, to find out which might be compatible
with this kind of sensor. The best
was a combination of polyester and
other synthetic fibers. To make wearable
sensors, the researchers embedded their
freeze-dried components into a small
section of this synthetic fabric, where
they are surrounded by a ring of silicone
elastomer. This compartmentalization
prevents the sample from evaporating or
diffusing away from the sensor. To dem -
onstrate the technology, the research ers
created a jacket embedded with about
30 of these sensors.
They showed that a small splash of liquid
containing viral particles, mimicking
exposure to an infected patient, can
hydrate the freeze-dried cell components
and activate the sensor. The sensors
can be designed to produce different
types of signals including a color
change that can be seen with the naked
eye or a fluorescent or luminescent signal
that can be read with a handheld
spectrometer. They also designed a wearable
spectrometer that could be integrated
into the fabric, where it can read
the results and wirelessly transmit them
to a mobile device.
To produce the diagnostic facemask,
the team embedded freeze-dried SHERLOCK
sensors into a paper mask. As with
the wearable sensors, the freeze-dried
components are surrounded by silicone
elastomer. In this case, the sensors are
placed on the inside of the mask, so they
can detect viral particles in the breath of
the person wearing the mask.
The mask also includes a small reservoir
of water that is released at the push of a
button when the wearer is ready to perform
the test. This hydrates the freezedried
components of the SARS-CoV-2 sensor,
which analyzes accumulated breath
droplets on the inside of the mask and
produces a result within 90 minutes.
The prototypes have sensors on the
inside of the mask to detect a user's status
as well as sensors placed on the outside of
garments to detect exposure from the
environment. The researchers can also
swap in sensors for other pathogens
including influenza, Ebola, and Zika, or
sensors they have developed to detect
organophosphate nerve agents.
For more information, contact Abby
Aba zorius at abbya@mit.edu; 617-253-2709.
Smart Wound Dressings with Built-In Healing Sensors
The built-in nanosensors glow to alert patients when a wound is not healing properly.
RMIT University, Melbourne, Australia
ultifunctional antimicrobial dressings
were developed that feature
fluorescent sensors that glow brightly
under UV light if infection starts to set in
and can be used to monitor the healing
progress. The smart dressings harness
the powerful antibacterial and antifungal
properties of magnesium hydroxide.
They are cheaper to produce than silM
ver-based
dressings but equally as effective
in fighting bacteria and fungi, with
their antimicrobial power lasting up to a
week. Currently, the only way to check
the progress of wounds is by removing
bandage dressings, which is both painful
and risky and gives pathogens the chance
to attack. Being able to easily see if something
is going wrong would reduce the
need for frequent dressing changes and
help to keep wounds better protected.
Tech Briefs, January 2022
Cov
The process to make the new magnesium hydroxide-based material, pictured before embedding
onto nanofibers, is simple to scale for potential mass production. (Photo: RMIT University)
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Tech Briefs Magazine - January 2022

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