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SPECIALITY

Quick COVID breathalyzer

could allow mass screening in

public places

ccording to experts, bringing
an end to the pandemic will
Arequire rapid screening of
people attending large gatherings,
such as conferences and weddings.
Even those who are asymptomatic
can still transmit COVID-19 to oth-
ers, making it important to identify
and isolate them until they are no
longer contagious. Now, research-
ers reporting in ACS Nano have
developed a prototype “breathalyz-
er” that can sensitively and accu-
rately diagnose COVID-19, even in
asymptomatic individuals, in less
than 5 minutes. A SERS-based breathalyzer can distinguish volatile organic compounds in the breath of
COVID-positive people in less than 5 minutes. Credit: Shi Xuan Leong and Yong Xiang
Leong, Nanyang Technological University
Currently, the “gold standard” for
COVID-19 testing is a technique
called reverse transcription-poly- the breathalyzer into a portable Ra- search Council, Singapore, A*STAR
merase chain reaction (RT-PCR), man spectrometer that characteriz- Singapore, the Max Planck Insti-
which is slow, requires an uncom- es the bound compounds based on tute-Nanyang Technological Univer-
fortable nasopharyngeal swab changes to the molecular vibrations sity Joint Lab and Nanyang Techno-
for sample collection and must of the SERS sensors. logical University.
be performed in a lab. The rapid
antigen test is much quicker but The team found that Raman Story Source:
has a higher rate of false negatives spectra from COVID-positive and Materials provided by American
and positives. Scientists have also -negative people were different Chemical Society. Note: Content
developed breathalyzer-type tests in regions responsive to ketones, may be edited for style and length.
for COVID-19, which rely on differ- alcohols and aldehydes, which they
ences in concentrations of volatile used to develop a statistical model Journal Reference:
organic compounds exhaled by for COVID diagnosis. They tested 1. Shi Xuan Leong, Yong Xiang
those infected with the coronavirus, the breathalyzer on 501 people in Leong, Emily Xi Tan, Howard Yi Fan
but most require bulky, nonport- hospitals and airports in Singapore, Sim, Charlynn Sher Lin Koh, Yih
able instruments for analysis. Xing who were shown by RT-PCR to Hong Lee, Carice Chong, Li Shiuan
Yi Ling and colleagues wanted to be negative (85.2%), positive and Ng, Jaslyn Ru Ting Chen, Desmond
develop a quick, convenient and ac- symptomatic (8.6%), or positive Wei Cheng Pang, Lam Bang Thanh
curate breathalyzer test that would and asymptomatic (6.2%) for the Nguyen, Siew Kheng Boong, Xue-
be suitable for on-site screening of coronavirus. The method had a mei Han, Ya-Chuan Kao, Yi Heng
large numbers of people. 3.8% false-negative and 0.1% Chua, Gia Chuong Phan-Quang, In
false-positive rate, comparable Yee Phang, Hiang Kwee Lee, Mo-
The researchers designed a hand- to RT-PCR tests, but it could be hammad Yazid Abdad, Nguan Soon
held breathalyzer that contains a completed on-site in less than 5 Tan, Xing Yi Ling. Noninvasive and
chip with three surface-enhanced minutes. The breathalyzer could Point-of-Care Surface-Enhanced
Raman scattering (SERS) sensors someday be a new tool to reduce Raman Scattering (SERS)-Based
attached to silver nanocubes. When the silent spread of COVID-19 in Breathalyzer for Mass Screen-
a person exhales into the device communities, the researchers say. ing of Coronavirus Disease 2019
for 10 seconds, compounds in their (COVID-19) under 5 min. ACS
breath chemically interact with the The authors acknowledge funding Nano, 2022; DOI: 10.1021/acsna-
sensors. Then, the researchers load from the National Medical Re- no.1c09371

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