• Bacteria-shredding insect wings inspire

    From ScienceDaily@1:317/3 to All on Mon Mar 21 22:30:44 2022
    Bacteria-shredding insect wings inspire new antibacterial packaging


    Date:
    March 21, 2022
    Source:
    RMIT University
    Summary:
    Inspired by the bacteria-killing wings of insects like cicadas,
    scientists have developed a natural antibacterial texture for use
    on food packaging to improve shelf life and reduce waste.



    FULL STORY ==========================================================================
    The lab-made nanotexture from an Australian-Japanese team of scientists
    kills up to 70% of bacteria and retains its effectiveness when transferred
    to plastic.


    ==========================================================================
    More than 30% of food produced for human consumption becomes waste,
    with entire shipments rejected if bacterial growth is detected.

    The research sets the scene for significantly reducing waste, particularly
    in meat and dairy exports, as well as extending the shelf life and
    improving the quality, safety and integrity of packaged food on an
    industrial scale.

    Distinguished Professor Elena Ivanova of RMIT University in Melbourne, Australia, said the research team had successfully applied a natural
    phenomenon to a synthetic material -- plastic.

    "Eliminating bacterial contamination is a huge step in extending the
    shelf life of food," she said.

    "We knew the wings of cicadas and dragonflies were highly-efficient
    bacteria killers and could help inspire a solution, but replicating
    nature is always a challenge.



    ==========================================================================
    "We have now created a nanotexturing that mimics the bacteria-destroying
    effect of insect wings and retains its antibacterial power when printed
    on plastic.

    "This is a big step towards a natural, non-chemical, antibacterial
    packaging solution for the food and manufacturing industry." The
    research, published in ACS Applied Nano Materials, is a collaboration
    between RMIT, Tokyo Metropolitan University and Mitsubishi Chemical's
    The KAITEKI Institute.

    In 2015, Australia exported $US3.1 billion of food and agricultural
    exports to Japan, making it the 5th largest exporter of such products
    to the country.

    How it works Dragonfly and cicada wings are covered by a vast array of nanopillars - - blunted spikes of similar size to bacteria cells.



    ==========================================================================
    When bacteria settle on a wing, the pattern of nanopillars pulls the
    cells apart, rupturing their membranes and killing them.

    "It's like stretching a latex glove," Ivanova said. "As it slowly
    stretches, the weakest point in the latex will become thinner and
    eventually tear." Ivanova's team developed their nanotexture by
    replicating insects' nanopillars and developing nanopatterns of their own.

    To assess the pattern's antibacterial ability, bacteria cells were
    monitored at RMIT's world-class Microscopy and Microanalysis Facility.

    The best antibacterial patterns were shared with the Japan team, who
    developed a way to reproduce the patterns on plastic polymer.

    Back in Australia, Ivanova's team tested the plastic nanopatterns and
    found the one which best replicated insect wings but is also easiest to fabricate and scale up.

    Ivanova said dealing with plastic was more difficult than other materials
    like silicon and metals, because of its flexibility.

    "The nanotexturing created in this study holds its own when used in rigid plastic. Our next challenge is adapting it for use on softer plastics,"
    she said.

    Since Ivanova and her colleagues discovered the bacteria killing nature
    of insect wings a decade ago, they've been working to design the optimal nanopattern to harness insects' bacteria-killing powers and use it on
    a range of materials.

    Until recently, it was difficult to find suitable technology to reproduce
    this nanotexturing on a scale suitable for manufacturing.

    But now technology exists to scale up and apply antibacterial properties
    to packaging, among a range of other potential applications, like personal protective equipment.

    Their new research builds on a 2020 study into using insect-inspired nanomaterials to fight superbugs.

    The team is keen to collaborate with potential partners in the next
    stage of the research -- upscaling the technology and determining the
    best ways to mass manufacture the antibacterial packaging.

    A pioneer in biomimetic antibacterial surfaces, Distinguished Professor
    Elena Ivanova leads the Mechano-bactericidal Materials Research Group
    in the School of Science at RMIT.

    The research was supported by the Foundation for Australia-Japan Studies
    under the Rio Tinto Australia-Japan Collaboration Project.

    Video: https://youtu.be/CyIrF5Jbrs8

    ========================================================================== Story Source: Materials provided by RMIT_University. Original written
    by Aeden Ratcliffe.

    Note: Content may be edited for style and length.


    ========================================================================== Journal Reference:
    1. Denver P. Linklater, Soichiro Saita, Takaaki Murata, Takashi
    Yanagishita,
    Chaitali Dekiwadia, Russell J. Crawford, Hideki Masuda, Haruhiko
    Kusaka, Elena P. Ivanova. Nanopillar Polymer Films as Antibacterial
    Packaging Materials. ACS Applied Nano Materials, 2022; 5 (2):
    2578 DOI: 10.1021/ acsanm.1c04251 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/03/220321103811.htm

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