The nanopropeller floats like a sperm
A hybrid of a corkscrew and a sperm became the smallest swimmer in the world
"The tape.Ru"Scientists have created a "nanopropeller" capable of moving in a liquid medium at a speed of up to 40 micrometers per second.
The description of the world's smallest swimmer is given in an article in the Nano Letters magazine. New Scientist briefly talks about the device (the Sperm-like nanopropeller is the smallest swimmer ever).
For creatures and objects of micro and nanoscale sizes, water is a rather viscous medium. One of the most effective ways of moving in viscous liquids is "screwing" on the principle of a corkscrew. This is how some bacteria that have a flagellum float in the water.
The "nanopropeller" created by the authors of the new work is a curved "flagellum" connected to a spherical head measuring from 200 to 300 nanometers. The length of the "flagellum" made of silicon is from one to two micrometers. To achieve a curved shape, scientists coated the "flagellum" with glass granules, and then sprayed silicon dioxide on it. The "flagellum" twisted around the granules, forming the necessary bends. A layer of silicon dioxide fixed the new shape.
The final stage of the creation of the "swimmer" was the application of a cobalt coating on one side of it. Cobalt has good magnetic properties, and when an external magnetic field was applied, the "nanopropellers" were oriented along magnetic lines. Using an alternating magnetic field, the scientists forced the "nanopropellers" to rotate. The maximum movement speed of the device was 40 micrometers per second. By changing the parameters of the magnetic field, the researchers used "nanopropellers" to "draw" complex signs on the water, for example, the letter "R".
In the future, such "swimmers" can deliver medicines to various tissues and organs of patients. Corkscrew and sperm hybrids have a number of advantages. Firstly, they are able to move efficiently in a liquid medium (that is, they will be able to swim through blood vessels). Secondly, they do not need internal energy sources to move. Thirdly, there are no moving parts in the design of "nanopropellers", which makes them more reliable.
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