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        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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