Scientists created a new device copying the remora fish’s natural ability to hitchhike on other animals.
Introduction
Have you ever wondered what it’s like inside your body? Much of it is wet, soft, and constantly moving! It’s hard for doctors to see what’s going on in that type of environment. It is also tricky to get medicines to certain places in your body. A device that could operate in wet and soft environments would be really helpful. But we don’t have anything like that right now. Luckily, there are animals we can learn from.
Remora fish are tiny and live in the ocean. They attach themselves to larger animals like whales and big fish. They have a disc on their heads that acts like a suction cup. The disc has several tiny, flap-like layers called lamellae. The organization of the lamellae has formed through evolution. They appear different depending on what host animal each species of remora attaches to.
We wanted to know if we could use the remora’s disc design to develop a device that could stick in wet and soft places. How does its structure help it stick so well to different animals and in changing conditions? Something that attaches to surfaces – even when the environment changes – could work well in the human stomach. For example, it could help deliver medicine to the area. There are also a lot of other potential uses. We set out to see if we could copy the remora’s disc design to build a small device that works in humans.
Methods
To find out more, we followed several steps.
We studied the organization of discs and lamellae in different species of remora. We figured out which designs allowed remoras to stick the best
to their hosts.
We designed and used microfabrication to build a Mechanical Underwater Soft Adhesion System – named MUSAS for short. This was inspired by the design elements that allowed remoras to attach well to soft and wet surfaces (Fig. 1).
We tested MUSAS on different surfaces and different pHs. This was to see how long it stayed attached.
Finally, we tested MUSAS inside live pigs and fish. We wanted to check that it would be safe for humans to use. We also recorded how long it stayed attached to a live animal.
Results
We found that the lamellae from the various remora species are organized in different directions. This is related to how fast their host swims. The disc also attaches differently based on the softness of the host’s skin.
It turns out that MUSAS sticks to lots of different surfaces. Even soft ones like pig stomach tissue in a cup full of water! MUSAS stayed attached for days in the live pig and fish. We also saw that it worked well in different pHs.
Discussion
We were able to design a device that attaches well to soft wet surfaces. And we figured it out by studying how remoras attach to their host’s skin. This process is called biologically inspired design. Studying how other animals have solved problems helps us to solve some of our own.
After designing and testing MUSAS, we explored some ways in which it could be useful.
Delivering medicine: MUSAS fits into a pill that can be swallowed. We loaded it with medicines for HIV/AIDS and tested it on pigs (Fig. 2).
Delivering gene therapy: MUSAS can deliver protein therapies that may benefit cancer treatment in the esophagus and gut.
Disease monitoring: We used MUSAS to detect acid reflux in pigs’ stomachs.
Environmental monitoring: We added a tiny sensor to MUSAS and attached it to a tilapia fish swimming in a tank. MUSAS measured the temperature of the water for almost 5 days without disturbing the fish (Fig. 3).
MUSAS worked well in all our tests! In the future, we hope to use MUSAS to help us develop other effective devices across a range of industries.
Conclusion
Our study shows that Nature still has many clever solutions that scientists can learn from! For example, burrs that stick to animal fur helped inspire Velcro. And the shape of a kingfisher’s beak helped engineers design quieter high-speed trains. By studying animals, we can discover new ways to solve problems. What other inventions might come from Nature? Next time you see an animal, look closely and think – could its special skills inspire the next big idea?
