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Japan researchers create biological-mechanical hybrid valve, eye medical uses


TOKYO -- A Japanese research group has created a valve using earthworm muscle tissue, and has high hopes the mechanical-biological hybrid device will prove useful in future medical devices, the team has announced.

    The valve shuts when a chemical substance is applied to the muscle tissue covering the mechanism, causing it to contract.

    "The valve can be operated with no electricity supply. It may be used in implantable medical devices as a fusion of a living organism and machine technology," said research team head Yo Tanaka of the Riken Center for Biosystems Dynamic Research.

    The researchers dissected a type of earthworm common to Japan and known scientifically as Megascolecidae, and spread the muscle tissue out to create a sheet measuring 1 centimeter by 2 centimeters. They then affixed the sheet to a valve designed to stop water flows when pressed down.

    When fluid containing acetylcholine, a neurotransmitter, was applied to the muscle sheet covering the valve, the sheet slowly contracted, completely stemming the water flow for at least a minute. Because muscle tissue relaxes when cleansed, the sheet could be used at least three times.

    An earthworm moves forward with reverse contractions of two types of muscle covering its body. The team chose the creature as it has extremely high muscle contractile force per unit area, and its circular structure makes it easy to use.

    The team had previously created a pump using earthworm muscle tissue in 2016, but it required electricity to stimulate the tissue.

    "I believe the latest idea can be applied to medical equipment that is difficult to power with electricity, such as implantable devices that release drugs in response to bodily chemicals," Tanaka said.

    The research results were published in the British journal "Scientific Reports."

    (Japanese original by Tomohiro Ikeda, Science & Environment News Department)

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