Suckermouth of Plecostomus Could Inspired Better Suction Devices (Bio-inspiration Example 2)

We observed that the Plecostomus was able to perform suction even under wet environment as we seen them in the aquarium. Or they can even suck on a rock full of slimy algae. This gives us an inspiration on how such action could benefit the human race. Having said that, researcher at University of Washinton's Friday Harbour Laboratories studied on the Northern clingfish and observed that this clingfish was able to produce high suction forces that can support up to 150 times their own body weight even under wet and slimy surfaces. This is something that even the current suction device cannot do. This sparked the idea that if the biomechanics of the clingfish or even the Plecostomus could be mimicked, it would be beneficial for the application of medical devices for surgical operations. Unlike the Plecostomus, the bellies of the clingfish provided the suction instead of their mouth, but either way both of the feature still allowed to be attached to a wet and slimy surface. The belly of the clingfish is like a rim of disc covered with a microscopic hair-like structure which created a layered effect that allowed them to attached to surfaces. On top of that, their disc-shaped bellies are also elastic where they can attach to uneven surfaces. 

The bio-inspiration from this creature is to be able to stick surgical devices into the patient's organs or tissue without harming them. The ability to retract delicate tissue without clamping them is what doctors desired in the laparoscopic surgery.....and the suction disc of the clingfish could lead a new way to manipulate organs without any risk of puncture. Besides for medical field, researchers also wants to develop a new type of tagging tool based on this suction feature to tag onto the body of animals such as whales without puncturing their skin with darts. Other than that, this type of development can also be very useful for shower caddy that uses suction cups as the bathroom is mostly wet all the time.

Figure 1 showed the underside of the clingfish. As seen in the figure, the disc-shaped belly of the clingfish looks very much similar to the suckermouth of the Plecostomus (see the comparison in Figure 2), which is why we believe they could also inspire for better suction devices besides the clingfish. We would also like to share a mind-blowing video on the suction power of the clingfish, you have to see it to believe it.

Figure 1. Underside of the clingfish - the disc-shaped belly

Figure 2. Comparison of the belly of clingfish and suckermouth of Plecostomus

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In addition to that, the Plecotomus was also able to perform suction attachment and respiration simultaneously. The idea of performing suction and respiration at the same time seems contradictory to scientist because the combination of both actions would result in leakage of air from the mouth. Fascinated by such observation, researcher Tom Geerinkx and his team research onto how is was possible for the Plecostomus to perform such paradoxal activity. The research data from Tom and his team found that the muscle oral valve actively separates the post-valvular buccal cavity from the pre-valvular sucker cavity. As such, the change in volume of the pre-valvular cavity are opposed to those of the post-valvular cavity, and this assures the suction function even during exhalation.


Reference

http://www.washington.edu/news/2015/05/04/puget-sounds-clingfish-could-inspire-better-medical-devices-whale-tags/

https://www.researchgate.net/publication/50269275_Suckermouth_armored_catfish_resolve_the_paradox_of_simultaneous_respiration_and_suction_attachment_A_kinematic_study_of_Pterygoplichtys_disjunctivus