If you want to gather climate-change data from the deep ocean, why not just hitch a ride with an organism that's going down there anyways? That's the thinking which led to the creation of "biohybrid jellyfish" which pack not one but two speed-boosting technologies.
The cyborg jellies are being developed by a team at the California Institute of Technology (Caltech) led by Prof. John Dabiri.
He's been messing around with the creatures for some time now, having previously brought us a jellyfish-inspired flexible pump, an artificial jellyfish composed of heart tissue and silicone, and a pacemaker-like device that enables jellyfish to swim three times faster than normal.
That last gizmo was developed as part of a project in which scientists from Caltech and Stanford University were looking at ways of using jellyfish to gather climate-change-related data such as water temperature, salinity, and oxygen levels from the ocean depths.
Since jellyfish naturally move up and down in the water column throughout the day, it made sense to equip them with data-recording sensors which could be retrieved at the surface. Doing so would be considerably cheaper and easier than building a fully robotic jellyfish. One problem, however, lay in the fact that the jellies swam too slowly to be of practical use.
The "pacemaker" helped in that regard. Hooked onto the underside of the animals, the small device delivered electric pulses which increased the rate of the pulsating movements which jellyfish use to propel themselves forward. As a result, their swimming speed increased from about 2 to 6 centimeters (0.8 to 2.4 in) per second.
That said, even faster would be better.
With that fact in mind, Dabiri and grad student Simon Anuszczyk have created 3D-printed "forebodies" which are attached to the top of a jellyfish's body. These streamlined devices reduce hydrodynamic drag, they're neutrally buoyant (so they don't cause the jelly to sink or rise), and they could serve as a housing for the sensors and other electronics.
In tests performed in a one-of-a-kind vertical water tank with a vertically flowing current, jellyfish equipped with both a pacemaker and a forebody were found to swim up to 4.5 times faster than natural jellyfish carrying a load of the same weight.
The scientists are now developing the pressure-resistant electronics, plus they hope to make the biohybrid jellyfish remotely steerable – so they can do more than just go straight up and down. And while the whole thing does perhaps sound a little ghoulish, Dabiri has given at least some consideration to the welfare of the jellies.
"Jellyfish are the original ocean explorers, reaching its deepest corners and thriving just as well in tropical or polar waters," he says. "Since they don't have a brain or the ability to sense pain, we've been able to collaborate with bioethicists to develop this biohybrid robotic application in a way that's ethically principled."
A paper on the research was recently published in the journal Bioinspiration & Biomimetics. You can see the bionic jellies in action, in the following video.
Source: Caltech
