Jellyfish cover the ocean, they can survive in varying temperatures, salinities, oxygen concentrations and below 3700 meters deep (about 2.3 miles). Scientists are currently researching ways to use live jellyfish as a means to explore the depths of the ocean by attaching a prosthetic to the bell of the 4-8 inch moon jellyfish. This prosthetic not only collects data about where the jellyfish swims, but also allows scientists to alter the speed and direction of the jelly.
A lead scientist creating the cyborg jellyfish, Nicole W. Xu at Stanford University, explains the differences in current technology for exploring the ocean. Xu notes models based on aquatic fish, manta ray and jellyfish. Xu explains that by mimicking “how animals naturally move, we can create more energy efficient aquatic vehicles.” She goes on to announce “[t]he solution that I’ve been working on is to create a bio-hybrid robot by using the animal itself as a natural scaffold.”
Xu explains the importance of greater ocean monitoring to “track changes in temperature, acidity and concentrations of nutrients to detect and prevent situations such as coral bleaching and algal blooms.”
Along with Nicole W. Xu, scientist John O. Dabiri has created a prosthetic with attached sensors which document the ocean. This method of oceanic exploration has proved much more effective than previous seafaring drones and may be 10-1000 times more energy efficient than swimming robots.
The scientists have been able to increase the average speed of the jellyfish three times with only two times greater metabolic expenditure. This will require jellyfish to eat more than usual when attached to the prosthetic but nowhere near previous estimates of up to nine times more energy expenditure.
Jellyfish are incredibly energy efficient animals. The swim controller prosthetic proposed by Xu and Dabiri harnesses the natural swim pattern of the jellyfish. The device details a battery powered dual electrode which is inserted into the jellyfish via a small wooden pole. The pulsing of these electrodes has been shown to stimulate the muscle contractions of the jellyfish, making it contract its bell. The jellyfish propels itself with each contraction, allowing for the remote operators of the prosthetic to control the speed of the jellyfish. Xu explains the electrodes create “an all or nothing muscle activation.” This allows for one pulse from an electrode to stimulate the entire jellyfish stroke, no matter the placement of the electrode.
The device uses the animal’s preexisting metabolism as a power source, greatly reducing the power required of the prosthetic in comparison to swimming robots. Additionally, scientists can harness the muscles of the jellyfish for specific maneuverability. Compared with swimming robots, the cyborg jellyfish is at lesser risk of being damaged due to the regenerative abilities of jellyfish.
Researchers have rebutted the ethical concerns of implementing this prosthetic, arguing jellyfish lack a brain and central nervous system necessary to feel pain. Moreover, when stressed jellyfish have been documented to secrete a thick mucus. This mucous has yet to be seen with the implemented prosthetic. Additionally, upon extraction of the prosthetic, jellyfish return quickly to normal. Xu explains the prosthetic “doesn’t seem to harm the jellyfish in the long term.” She elaborates that once the prosthetic is removed, jellyfish have been reported to return immediately to typical function.