Tech Briefs Magazine - June 2021 - 49

which can help doctors guide cancer
radiation therapy.
In premature infants, supplemental
oxygen may be required but doctors
don't have a reliable tissue readout of
oxygen concentration. Fur ther miniaturized
versions of this device could help
better manage oxygen exposure in
preterm infants in the intensive care
nursery setting and help minimize some
of the negative consequences of excessive
oxygen exposure such as reti nopathy of
prematurity or chronic lung disease.
The technology could be further
improved by housing the sensor so that it
could survive long term in the body.
Further miniaturizing the device would
also simplify the implantation process,
which currently requires surgery. In addition,
the optical platform in the sensor
could be readily adapted to measure
other biochemistry in the body. By just
changing the platform that was built for
the oxygen sensor, the device can be modified
to measure, for example, pH, reactive
oxygen species, glucose, or carbon
dioxide. If the packaging could be made
smaller, the device could be injected into
the body with a needle, or through laparoscopic
surgery, making the implantation
even easier.
For more information, contact Kara Manke
at kjmanke@berkeley.edu; 510-643-7741.
Heated Facemask Filters and Inactivates Coronaviruses
The reusable mask would include a heated copper mesh powered by a battery and
surrounded by insulating neoprene.
Massachusetts Institute of Technology, Cambridge
F
acemasks have been shown effective
at filtering out viruses such as the
SARS-CoV-2 virus, thereby reducing the
risk of infection. Researchers hope to go
one step further and create a mask that
inactivates viruses using heat. The aim is
to build masks that incorporate a heated
copper mesh. As the person wearing the
mask breathes in and out, air flows
repeatedly across the mesh and any viral
particles in the air are slowed and inactivated
by the mesh and high temperatures.
Such a mask could be useful for
healthcare professionals as well as members
of the public in situations where
social distancing would be difficult to
achieve such as a crowded bus.
The mask does not primarily block the
virus. It actually lets the virus go through
the mask but slows and inactivates it.
Masks commonly worn are designed to
capture some of the virus and while they
do offer protection, they do not inactivate
the virus and sterilize the air. The
team set out to design a mask that would
kill viruses using heat. They used copper
mesh as the heating and capture element
and performed some mathematical modeling
to determine the optimal temperature
range they would need to achieve to
kill corona viruses flowing inward or outward
from natural breathing.
The researchers calculated how rapidly
corona viruses degrade at different temperatures
and trapping conditions and
found that a temperature of about 90 °C
could achieve between a thousandfold
and millionfold reduction in viral particles,
depending on the final mask size.
The temperature can be achieved by running
an electrical current across a 0.1mm-thick
copper mesh or thermoelecTech
Briefs, June 2021
Cov
The new masks inactivate viruses using heat. (Image: Courtesy of the researchers)
tric heater powered by a small battery.
The current prototypes include a 9-volt
battery, which would provide enough
power to heat the mask for a few hours
and would cool the air before it is inhaled.
The team enhanced the efficiency of
virus deactivation by taking advantage of
the breath to create a type of reactor
known as a reverse-flow reactor. As the
person wearing the mask breathes in and
out, the airflow continually reverses,
allowing any viruses in the mask to pass
over the mesh many times and making it
more likely that they will be deactivated.
Purified air flows out of vents on both
sides of the mask. The copper mesh is
surrounded by neoprene, an insulating
material that prevents the outside of the
mask from becoming too hot to wear.
www.techbriefs.com
ToC
N95 respirators, surgical masks, and
cloth masks are effective and should be
used during the pandemic as directed
but one potential advantage of heated
masks is that because they kill the virus,
they don't need to be decontaminated or
thrown away after use. Additionally, they
may offer extra protection by eliminating
the virus rather than only filtering it. The
new mask enables the wearer to breathe
in medically sterile air and breathe out
medically sterile air, protecting people
nearby. Heated masks would be more
expensive than cloth masks or surgical
masks but they may be useful in situations
where exposure risk is high and
cost is less of a concern.
For more information, contact Abby
Abazorius at abbya@mit.edu; 617-253-2709.
49
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Tech Briefs Magazine - June 2021

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