If you've ever watched documentaries on sharks or have watched them out in the water, you've probably noticed their smaller companions, remora fish. These fish attach themselves to the larger marine creatures including sharks, turtles, manta rays and the like for an easy mode of transportation, to gain the protection provided by being one with the bigger animal, and for food. Yet their hitching on to a shark causes no harm to the shark itself. That's the aspect of remora fish that scientists are most interested in -- how do they achieve such a solid attachment without damaging their host?
Researchers from Georgia Tech are taking a closer look at the top of remoras' heads, at the structure and tissue properties of the area that adheres to the host, and hope to make a bio-inspired adhesive with the same qualities.
The remora’s suction plate is essentially a specialized dorsal fin which has become a disc covered by connective tissue which seals the fish to its host. "The intricate skeletal structure enables efficient attachment to surfaces including sharks, sea turtles, whales and even boats," reports Georgia Tech.
“While other creatures with unique adhesive properties – such as geckos, tree frogs and insects – have been the inspiration for laboratory-fabricated adhesives, the remora has been overlooked until now,” said GTRI senior research engineer Jason Nadler. “The remora’s attachment mechanism is quite different from other suction cup-based systems, fasteners or adhesives that can only attach to smooth surfaces or cannot be detached without damaging the host.”
3-D rapid prototypes of an enlarged lamella (in hand) and mineralized tissue within a remora adhesive disk (on table).
Along with detailed studies of remora species and their abilities, the researchers are using 3D printing to prototype versions of the remora's specialized dorsal fin. “We are not trying to replicate the exact remora adhesion structure that occurs in nature,” explained Nadler. “We would like to identify, characterize and harness its critical features to design and test attachment systems that enable those unique adhesive functions.”
According to the researchers, finding out the trick to this fish's reversible adhesion could be a benefit for many industries. It "could be used to create pain- and residue-free bandages, attach sensors to objects in aquatic or military reconnaissance environments, replace surgical clamps and help robots climb."