13 March 2017

A "robot amoeba" has been created under the control of DNA

Oleg Lischuk, N+1

Japanese scientists have developed an amoeboid micro robot consisting only of biomolecules and capable of moving controllably. The report on the work is published in the journal Science Robotics (Sato et al., Micrometer-sized molecular robot changes its shape in response to signal molecules).

Robot with microtubules protruding under the membrane
(here and below are the drawings from the article in Science Robotics)

To date, many technologies have been developed to create micro- and nanorobots that can move in various environments, including living organisms, under the control of magnetic, chemical, ultrasonic and other signals. Among them there are molecular robots constructed from biological compounds, but it has not been possible to provide them with acceptable controllability so far.

To solve this problem, the staff of Tohoku University and the Japanese Advanced Institute of Science and Technology took as a basis a liposome - a liquid–filled sphere of a double lipid layer similar to cell membranes. It contains a "skeleton" of microtubules, as well as a "motor" in the form of kinesin molecules that can "walk" through microtubules due to the energy of adenosine triphosphate (ATP).

Kinesin molecules are linked to synthetic single-stranded DNA, which serves as a "key". On the inner side of the membrane there are "anchors", also consisting of single-stranded DNA and fixed in the lipid layer by cholesterol molecules. In the liquid medium of the liposome, there are photosensitive DNA sequences that, under the influence of radiation of a certain frequency, bind to "keys" and "anchors", connecting them to each other to form double-stranded DNA.

The principle of operation of the robot

When the "motors" are fixed by "anchors" to the membrane, they begin to "step" along the microtubules, changing the shape of the liposome and providing it with an amoeboid movement. In the absence of a signal or depletion of ATP reserves, the kinesin "motors" detach from the membrane and accumulate near the microtubules, as a result of which the molecular robot returns to a spherical shape and stops moving.

The development is a platform that can be equipped with specified functions by adding sensors, drug tanks or other components to the liposome. One of the authors Shinichiro Nomura (Shin-ichiro Nomura) He expressed hope that on its basis it will be possible to create nanorobots capable of functioning inside a living cell.

Other interesting developments in the field of nanorobotics include examples of devices that move due to enzymes, light and magnetic flagella. Israeli DNA origami nanorobots deserve special mention, which are able to secrete a certain dose of the drug under the control of thought.

Portal "Eternal youth" http://vechnayamolodost.ru  13.03.2017

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