Barnacles have been attaching themselves to ships for as long as humans have been sailing and the strength of their natural glue is both frustrating and amazing. Charles Darwin figured out where it came from (cement glands in barnacle larvae) but how this superglue works so well under water has been a mystery … until now.
Barnacles are arthropods related to crabs and lobsters and have two larval stages. When a barnacle egg hatches, out pops the nauplius which swims around feeding on plankton. It eventually becomes a cyprid and that’s when the problems for boat owners starts. The cyprid looks for a surface to attach to and when it finds one, it squirts the glue from its cement gland, pushes against the surface and never moves again.
Scientists have known for some time that the barnacle bioadhesive has two components and that they worked together in some fashion. But how? And how does this barnacle glue stick to a wet surface?
The current issue of the journal Nature Communications provides the answers. A team of researchers from Newcastle University and funded by the US Office of Naval Research used 2-photon microscopy to study the adhesion process and found that the first component released by the barnacle cyprid is an oily droplet that clears the water from the surface. The second component is a phosphoprotein adhesive that does the sticking.
Study author Dr. Nick Aldred tells what this discovery means.
It’s an incredibly clever natural solution to this problem of how to deal with a water barrier on a surface. It will change the way we think about developing bio-inspired adhesives that are safe and already optimised to work in conditions similar to those in the human body, as well as marine paints that stop barnacles from sticking.
The medical adhesive applications are promising but still in the future. However, anti-barnacle paint could save the shipping industry some of the $7.5 billion a year in fuel wasted on fighting drag.
Another elegant solution to a number of problems, courtesy of nature.