Cnidarian weapon – inspiration for microdevices with biomedical application
Jellyfish, sea anemones and other cnidaria wield explosive weapons – harpoon-like 'stings' that burst from tiny capsules or nematocysts on the surface of their skin, impaling prey or deterring predators. Here scientists reconstruct a sea anemone harpoon, the basitrichous isorhiza, from scans taken with scanning electron microscopy. The shaft of the sting (blue) is connected to a coiled tubule (pink) which springs outwards, skewering a meal and turning the capsule inside out by a process called eversion. With the process zipping by in 700 nanoseconds, the team looked closely at the biomechanics involved, finding the strands of the shaft uncoil outside the capsule, propelling an inner tubule covered in barbs towards the target. The elegant design of this deadly micromachine may now be repurposed, putting the same mechanics into needles to treat humans – a helping hand from cnidarians, our distant genetic ancestors.
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