World’s Smallest Benchy Shows Off What 3D-Printing Can Do For “Microswimmers”

We’ve said it before, but we cast a wary eye at any superlative claims that come our way. “World’s fastest” or “world’s first” claims always seem to be quickly debunked, but when the claim of “World’s Smallest Benchy” is backed up by a tugboat that two dozen E. coli would have a hard time finding space on, we’re pretty comfortable with it.

Of course the diminutive benchmark was not printed just for the sake of it, but rather as part of a demonstration of what’s possible with “microswimmers”, synthetic particles which are designed to move about freely in microscopic regimes. As described in a paper by [Rachel P. Doherty] et al from the Soft Matter Physics lab at Leiden University, microswimmers with sizes on the order of 10 to 20 μm can be constructed repeatably, and can include a small area of platinum catalyst. The catalyst is the engine of the microswimmer; hydrogen peroxide in the environment decomposes on the catalyst surface and provides a propulsive force.

Artificial microswimmers have been around for a while, but most are made with chemical or evaporative methods which result in simple shapes like rods and spheres. The current work describes much more complex shapes — the Benchy was a bit of a flex, since the more useful microswimmers were simple helices, which essentially screw themselves into the surrounding fluid. The printing method was based on two-photon polymerization (2PP), a non-linear optical process that polymerizes a resin when two photons are simultaneously absorbed.

The idea that a powered machine so small could be designed and manufactured is pretty cool. We’d love to see how control mechanisms could be added to the prints — microfluidics, perhaps?

Water Runner Robot

Researchers at Carnegie Mellon University’s NanoRobotics Lab have developed a robot that is capable of running on the surface of a pool of water. Like their wall climbing Waalbot, the Water Runner was inspired by the abilities of a lizard, in this case, the basilisk. The team studied the motions of the basilisk and found morphological features and aspects of the lizard’s stride that make running on water possible. Both the lizard and the robot run on water by slapping the surface to create an air cavity like the one above, then push against the water for the necessary lift and thrust. Several prototypes have been built, and there are variants with 2 or 4 legs and with on and off-board power sources. You can see a slow motion video of the robot’s movement below.

The purpose of their research is to create robots that can traverse any surface on earth and waste less energy to viscous drag than a swimming robot would. Though another of the team’s goals is to further legged robot research, the Water Runner is not without potential practical applications. It could be used to collect water samples, monitor waterways with a camera, or even deliver small packages. Download the full abstract in PDF format for more information.

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