Gentle “pasta fingers” instead of rigid claws: biologists have shown the potential of soft robotics for the research of sensitive marine animals. The jellyfish remain relaxed in the grip of soft structures, their tests show. Conventional gripping instruments, on the other hand, activate stress genes in sensitive animals, the analyzes showed. The gentle grippers are therefore particularly well suited for minimally invasive and near-natural research into sensitive marine animals, the scientists say.
Research focuses on jellyfish, corals and the bizarre creatures of the deep sea. In addition to their biological importance, scientists are also interested in the potential of genes and active substances in these living things. Sampling and behavioral observations should be carried out as gently and non-destructively as possible. So far, however, marine research has been rather rabid: Rigid gripping arms of diving equipment grab the sensitive creatures, injure them or keep them trapped in their hard claws. “Our goal is to be as gentle and careful as possible when we penetrate these habitats and study their creatures,” says marine biologist David Gruber of the City University of New York.
An ultra-smooth gripper
The focus was on the potential of soft robotics. For some time now, scientists have been developing robots made of soft materials as alternatives to conventional systems made of metal or hard plastics. The developer Nina Sinatra from Harvard University in Cambridge used the methods of soft robotics in a previous project to develop an ultra-smooth gripping device: Instead of rigid structures, it has noodle-like silicone fingers that can gently wrap around an object. The fingers have water-filled cavities that allow opening and closing due to changes in pressure. Each finger exerts an extremely low pressure when moving – it is less than when a human eyelid is closed.
Tests have already shown that jellyfish can actually be captured and held gently with the device. In principle, however, rigid gripping arms can enclose the animals without injury and hold them captive. The scientists have now investigated the extent to which the particularly gentle treatment for the jellyfish plays a role. But how can you find out how a jellyfish is doing? As the researchers explain, this is possible through genetic methods that record the activities of hereditary systems. This allows conclusions to be drawn about how organisms react to stimuli: “Imagine that you are sitting at your desk satisfied and I measure which genes are active. Then I trap you with a claw hand and record the gene activity again. A comparison of the patterns can then show the level of stress that was caused by the disorder, ”explains Gruber.
Tracking down jellyfish
Similarly, as part of their study, the researchers examined the extent to which gene activity differs from jellyfish that were caught with rigid grippers compared to the soft robo hands. As they report, the relatively cautiously treated test animals showed a gene expression pattern that resembled undisturbed individuals. The jellyfish enclosed in the claw, on the other hand, activated genes that are linked to stress reactions, the researchers report. Some of these were “repair genes”, which indicated that the animals were preparing for physical damage. “With the genetic process, we were able to confirm that the soft robot actually enables gentler handling of the jellyfish,” sums up the first author of the study Michael Tessler from the American Museum of Natural History in New York.
However, the importance of the result goes beyond the research of jellyfish, emphasizes Gruber: “We used them as our test organisms. Since we were able to show that this method can save stress on sensitive beings such as jellyfish, it now becomes clear that soft robots could be used in various applications in marine research in which a gentle approach is important, ”says the marine biologist.
The developer of the soft robo hands is also pleased with the success: “It is once again shown how engineers can use robots to give robots skills that would not be possible with conventional concepts. A combination of flexible, robust and light materials means that soft robots can work reliably in the deep sea and at the same time are apparently gentle enough to safely interact with sensitive marine organisms, ”says Sinatra.
Video: Harvard University
Sources: Cell Press, Harvard University, professional article: Current Biology, doi: 10.1016 / j.cub.2020.01.032