• Nanoparticles could enable a more sensit

    From ScienceDaily@1:317/3 to All on Wednesday, April 13, 2022 22:30:46
    Nanoparticles could enable a more sensitive and durable rapid COVID-19
    test

    Date:
    April 13, 2022
    Source:
    American Chemical Society
    Summary:
    Researchers have developed a rapid test that uses molecularly
    imprinted polymer nanoparticles, rather than antibodies, to detect
    SARS-CoV-2. The new test is more sensitive and works under more
    extreme conditions than antibody-based tests.



    FULL STORY ========================================================================== Rapid antigen tests can quickly and conveniently tell a person that they
    are positive for COVID-19. However, because antibody-based tests aren't
    very sensitive, they can fail to detect early infections with low viral
    loads. Now, researchers reporting in ACS Sensorshave developed a rapid
    test that uses molecularly imprinted polymer nanoparticles, rather than antibodies, to detect SARS-CoV-2. The new test is more sensitive and
    works under more extreme conditions than antibody-based tests.


    ==========================================================================
    The gold standard test for COVID-19 diagnosis remains the reverse transcription-polymerase chain reaction (RT-PCR). Although this test
    is highly sensitive and specific, it generally takes 1-2 days to get
    a result, is expensive and requires special lab equipment and trained personnel. In contrast, rapid antigen tests are fast (15-30 minutes),
    and people can take them at home with no training. However, they lack sensitivity, which sometimes results in false negatives. Also, the tests
    use antibodies against SARS-CoV- 2 for detection, which can't withstand
    wide ranges of temperature and pH.

    Marloes Peeters and Jake McClements at Newcastle University, Francesco Canfarotta at MIP Diagnostics, and colleagues wanted to make a low-cost,
    rapid, robust and highly sensitive COVID-19 test that uses molecularly imprinted polymer nanoparticles (nanoMIPs) instead of antibodies.

    The researchers produced nanoMIPs against a small fragment, or peptide,
    of the SARS-CoV-2 spike protein by creating molecular imprints, or molds,
    in the nanoparticles. These nanoscale binding cavities had a suitable
    size and shape to recognize and bind the imprinted peptide and, therefore,
    the entire protein.

    They attached the nanoparticles that bound most strongly to the peptide to printed electrodes. After showing that the nanoMIPs could bind SARS-CoV-2,
    they developed a 3D-printed prototype device that detects binding of
    the virus by measuring changes in temperature.

    When the team added samples from seven patient nasopharyngeal swabs to
    the device, the liquid flowed over the electrode, and the researchers
    detected a change in temperature for samples that had previously tested positive for COVID-19 by RT-PCR. The test required only 15 minutes,
    and preliminary results indicated that it could detect a 6,000-times
    lower amount of SARS-CoV-2 than a commercial rapid antigen test. Unlike antibodies, the nanoMIPs withstood warm temperatures -- which could
    give the test a longer shelf life in hot climates - - and acidic pH
    -- which might make it useful for monitoring SARS-CoV-2 in wastewater
    and saliva samples. However, to prove that the test has a lower false
    negative rate than existing rapid antigen tests, it must be tested on
    many more patient samples, the researchers say.

    The authors acknowledge funding and support from Newcastle University,
    the Rosetrees Trust, the Wellcome Trust, MIP Diagnostics and the Fonds
    de la Recherche Scientifique.


    ========================================================================== Story Source: Materials provided by American_Chemical_Society. Note:
    Content may be edited for style and length.


    ========================================================================== Journal Reference:
    1. Jake McClements, Laure Bar, Pankaj Singla, Francesco Canfarotta,
    Alan
    Thomson, Joanna Czulak, Rhiannon E. Johnson, Robert D. Crapnell,
    Craig E.

    Banks, Brendan Payne, Shayan Seyedin, Patricia Losada-Pe'rez,
    Marloes Peeters. Molecularly Imprinted Polymer Nanoparticles Enable
    Rapid, Reliable, and Robust Point-of-Care Thermal Detection of
    SARS-CoV-2. ACS Sensors, 2022; DOI: 10.1021/acssensors.2c00100 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/04/220413090935.htm

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