U.S. military research reports that new liquid-coated air filters help trap airborne pathogens

Researchers at the University of Maine and the University of Massachusetts Amherst have designed new liquid-coated air filters that can better detect and analyze airborne bacteria and viruses, including those that cause COVID-19
, early.

While traditional air filters help control the spread of disease in public places such as hospitals and transportation hubs, they struggle to keep captured pathogens alive for testing
.
This inefficiency inhibits scientists' ability to identify biological threats early, hindering any response and protection
.

The research team, led by Caitlin Howell, an associate professor of biomedical engineering at UMaine, has developed a composite membrane with a liquid layer for filtration, better suited to capturing surviving bacterial and viral samples for analysis
.
Nepenthes has a smooth edge and inner wall that allows insects to fall and get trapped in
its digestive juices.
The researchers mimicked the membrane of Nepenthes in, and by keeping captured bacteria and viruses available for examination, their new liquid-coated air filter could enhance air sampling efforts, early pathogen detection, and biomonitoring
of national security.

The researchers developed a variety of filters containing liquid-coated membrane technology and tested their ability to
preserve and release E.
coli, SARS-COV-2, and JC polyomavirus, which attacks the central nervous system.
In particular, they found that high-efficiency particulate air filters (HEPAs) with liquid coatings captured more airborne pathogens
than filters without a liquid coating.
The team published their findings
in the journal ACS Applied Materials & Interfaces.

"In the early stages of the pandemic, we observed in real time how many problems were caused by no one knowing where airborne viruses were and were not
.
We have a system in place that can begin to address that need, so we have a responsibility to step up and help," Howell said
.

"I think this technology will give us confidence for our patients and for us as caregivers to make us safer when we conduct care," said
Dr.
Robert Bowie, medical director of the Eastern Emergency Medical Research Institute.
"Knowing that we've improved environmental safety makes it easier for us to leave our loved ones and go to work and take care of others
.
"

The program is a major interdisciplinary effort
spanning the fields of biomedical engineering, chemical engineering, and microbiology.
The UMaine biomedical engineering team includes first author and Susan J.
Hunter Presidential Award winner Daniel Regan, Chun Ki Fong, a graduate school of engineering engineering (GSBSE) doctoral student, and former master's student Justin Hardcastle
.
The microbiology team, led by associate professor Melissa Maginnis, included Avery Bond, a doctoral student in molecular and biomedical sciences, and Claudia Desjardins, an assistant in the university's
wastewater analysis laboratory at the time.
The chemical engineering team at UMass Amherst consisted of
Professor Jessica Schiffman and PhD student Hung Shao-Hsiang.

Regan first presented the initial concept of a liquid-coated air filter to his dissertation committee in March 2019 to capture aerosols containing bacteria, based on conversations with military researchers and concerns
about detecting potential contamination during medical evacuations.
He also delivered a presentation titled "Optimizing Liquid-Gated Membranes for Bioaerosol Capture and Release" at the 2020 UMaine Student Symposium, which earned him the Susan J.
Hunter Presidential Research Impact Award
.

Howell, Maginnis, Schiffman, and Holmes realized that this also applied to virus-containing aerosols in the early stages of the COVID-19 pandemic and applied for a grant from the National Science Foundation, a concept that was further developed and refined
.
In 2020, the project won a $225,000 NSF EAGER Award, an early-concept grant to support "untested but potentially transformative research ideas or methods.
"

"COVID-19 is a constant reminder that biosurveillance capabilities provide decision-makers with important information that can provide detailed information
for reducing biological risks," Regan said.
In the last year alone, the world experienced severe pathogens, including an outbreak of monkeypox, a resurgence of the Ebola virus in Sudan, and a large number of cases
of respiratory syncytial virus infection (RSV).
The need for early warning of pathogens is very large, and we hope that further investment in liquid-coated air filters can help improve biomonitoring capabilities
for aerosol detection.
”

Daniel P.
Regan, ChunKi Fong, Avery C.
S.
Bond, Claudia Desjardins, Justin Hardcastle, Shao-Hsiang Hung, Andrew P.
Holmes, Jessica D.
Schiffman, Melissa S.
Maginnis, Caitlin Howell.
Improved Recovery of Captured Airborne Bacteria and Viruses with Liquid-Coated Air Filters.
ACS Applied Materials & Interfaces, 2022; 14 (45): 50543