Scientists are building cyborg jellyfish to explore ocean depths
Understanding the awakenings and whirlpools that jellyfish produce when swimming is crucial, according to Wu, et al. The velocimetry of the image of particles (PIV) is a vital tool to study the flow phenomena and biomechanical propulsion. Piv essentially follows tiny particles of tracker suspended in water by lighting them with a laser light. The technique generally rests on hollow glass spheres, polystyrene balls, aluminum flakes or synthetic granules with special optical coatings to improve light reflection.
These particles are easily available and have the right size and good density for flow measurements, but they are very expensive, costing the book up to $ 200 in some cases. And they have associated health and environmental risks: glass microspheres can cause skin or eyes irritation, for example, although it is not a good idea to inhale polystyrene beads or aluminum flakes. They are not digestible by animals either and can cause internal damage. Several biodegradable options have been offered, such as yeast cells, milk, micro-algae and potato starch, which are easily available and cheap, costing as little as $ 2 books.
Wu thought that starch particles were the most promising as biodegradable tracers and decided to study several different types of starch to identify the best candidate: in particular, corn starch, arrowroot starch, baking powder, jojoba pearls and nutshell powder. Each type of particle has been suspended in water tanks with moon jellyfish, according to their movement with a PIV system. They evaluated their performance according to the size, density and diffusion properties of the particle laser.
Among the various candidates, corn starch and starch arrow has proven to be better suited to PIV applications, thanks to their uniform density and distribution, while the Arrowroot starch worked better with regard to laser broadcasting tests. But corn starch would be well suited to applications that require larger tracker particles because it has produced larger laser diffusion points in experiments. The two candidates corresponded to the performance of the particles of synthetic PIV tracer commonly used in terms of precisely visualization of the flow structures resulting from swimming jellyfish.
DOI: Physical review fluids, 2025. 10.1103 / BG66-976X (about DOI).
