Researchers at Leiden University have 3D printed the smallest boat in the world: a 30-micrometre copy of Benchy the tug boat, a well-known 3D printer test object. This boat is so small, it could float down the interior of a human hair.
The 3D-printed boat is part of an exploration of microswimmers, microscopic organisms or objects that can move through liquids. Natural examples of microswimmers are bacteria and sperm. This tiny Benchy propels itself using a bit of platinum that reacts with hydrogen peroxide.
The most interesting thing is how they were able to print the little boat’s cockpit, an open space that requires lots of geometric trickery to build.
“A laser is focused inside a droplet that locally hardens in the focal spot of the laser,” said researcher Daniela Kraft. “By moving the laser through the droplet in a controlled way, we can write the swimmer shape that we want.”
“Because the print is taking place inside the droplet, and we are printing layer by layer, we can maintain the open space,” she said.
Why did they print a little swimming boat? Because it was fun!
“3D Benchy is a structure that has been designed to test macroscopic 3D printers because it has several challenging features, and it was natural to also try it at the micrometre scale,” said Kraft. “In addition, making a swimming micrometre-sized boat is fun.”
Their research paper, titled “Catalytically propelled 3D printed colloidal microswimmers” appears in the journal Soft Matter.