Like anything you love dearly, jellyfish must be handled with extreme care and tenderness. These deep-sea creatures offer a wealth of knowledge for researchers, but the handling required to complete experiments can sometimes cause harm and distress for the animal. How to continue such experiments in a safer way without losing effectiveness? Scientists have designed soft robots that can gently grasp jellyfish and similar delicate creatures without causing distress.
To determine just how effective these new robotic graspers were, scientists set out to measure jellyfishes' stress responses through genomics in a new study published Monday in the journal Current Biology.
When it comes to handling animals for experiments, the authors write that before soft robotics, the standard tool had been a rigid, claw-like gripper. These kinds of experimental tools have been known to harm or even kill sea creatures in the name of science. Researchers behind this study say that ultra-soft robots offer a much-needed alternative for this kind of fieldwork. Because jellyfish can't outwardly express their discomfort or pain the way we're used to in mammals, in this study the researchers sequenced the jellyfishes' genes to take a closer look at their response.
Senior author on the study and Professor of Biology at the City University of New York, David Gruber, said in a statement that it's similar to measuring how disturbed someone might be if you disrupted their day to prod them with a poker.
"Imagine you're sitting very happily at your desk and I take a measurement of what genes are active, and then I poke you with a claw hand."
"Imagine you're sitting very happily at your desk and I take a measurement of what genes are active, and then I poke you with a claw hand," said Gruber. "I'd then look at how differently your genes reacted compared to when you were sitting unbothered; the strength of that difference can act as an indicator of your level of stress."
The jellyfish used in this trial were divided into four different trial groups. The high-stress group was held by the rigid, claw-like gripper and given a good shake. A slightly lower stress group was held by the claw without shaking while a third was held without shaking by a soft robot. The final control group was contained but not physically manipulated by either the claw or the soft robot.
Through looking at a variety of genetic responses, the team found again and again that the jellies held by the rigid claw gripper expressed either more stress than the soft robot group or expressed stress genes that the soft robot group didn't express altogether. Interestingly, for even the group just held (but not shaken) by the claw gripper, the jellyfish expressed genes related to self-repair, which the report says could mean the jellyfish were expecting damage or harm to come from the gripper.
But, Gruber tells Inverse that the forces exerted on the jellyfish using the ultra-soft gripper are so gentle they'd be barely susceptible to even humans.
"[These grippers] are exerting about one 10th of the pressure of the eyelid resting on the eyeball," says Gruber.
This extreme gentleness is made possible by a distributed system of ultra-light nanofiber fingers, co-author and graduate student at Harvard University's Wyss Institute for Biologically Inspired Engineering during the time of the study, Nina Sinatra, tells Inverse.
"[Previous approaches] more often used some sort of power grasp," says Sinatra. "Which is basically like if you imagine yourself grabbing a handle on a door. Whereas our grasp method is something called a caging grasp. So all those little thin fingers are curling and then crossing over each other and forming a kind of basket, like a network. And that just cradles the animals... and [pressure] ends up being more distributed because you have this network of fingers."
With the benefits of soft robotic handling demonstrated in this study, Gruber says it could lead the way for using such tools in other experimental scenarios as well.
"We just used [jellyfish] as our sample organisms," says Gruber. "Now that we've shown this method can cause less stress to something as fragile as a jellyfish, it really proves our hypothesis that soft robots in the deep sea can be effective tools for all manner of delicate interactions."
The authors write that this approach could also be translated from scientific exploration to agriculture and medicine as well, such as picking fruit without bruising it or assisting in physical rehabilitation of stroke patients. Gruber also tells Inverse that he hopes this study can be part of a turn toward a more respectful kind of deep-sea exploration, different from invasive extraction practices used today in deep-sea mining.
"We're beginning to explore the deep-sea," says Gruber. "There's many different ways we can approach this. We can approach it with respect and trying to be as gentle as possible, [which is] in contrast to the more invasive extractive ways in which we're looking at the deep-sea... As we begin to have the tools and technology to go to the bottom of the ocean and meet these animals and study them -- this is part of a larger theme of just being as gentle and respectful as we can."
Going forward with the ultra-soft, caged grip approach, Sinatra says that researchers are also looking for ways to incorporate more sensors into these thin fingers, including sampling systems or cameras.
"You could think about this hand having all these different types of functions," says Sinatra. "That can give you a lot of different types of information about the animal that you're attracting, which is especially compelling if you think about this grasper being deployed in an RV in the deep-sea and maybe you see an animal that you've never seen before or only seen once. You don't want to necessarily take it out of the ocean, but you do want to learn more about it."