At this point it seems a page on spider silk would be in order. But as ubiquitous as spider silk is, we'll skip it in lieu of something less familiar -- barnacles!


What exactly is the best analogy for a barnacle? An in-law who's worn out their welcome; a pesky, nosey neighbor; an insignificant other with a bad case of fatal attraction? Heck, let's just say that all three will do. Barnacles are annoying, unavoidable, and relentless!

Just to show you how bad barnacles are, here's a before and after picture of the hull of a really big ship:

Before	After

Simply amazing, ain't it? The secret to the barnacle's fortitude is a super strong adhesive. The barnacle literally glues itself wherever it wants, incorporating itself into a composite like structure.

All of the thousands of species of barnacles spend their early life roaming the open waters. The rebellious youngsters are called nauplii. After adolescence, the nauplii molt into a larval state called cyprids. These are the little devils that cement themselves permanently to docks, ships, turtles, whales and rocks.

Barnacles don't wander aimlessly. They tend to camp out with other barnalces or in places where other barnacles have been before. This fact explains why ships become easily infested. This also explains why barnacles will never explore the far reaches of our galaxy.

How they stick

Barnacles stick to teflon! They actually stick to teflon. The mechanism by which this feat is accomplished is kind of like setting epoxy glue. You have to mix the stuff in the two tubes together, else nothing happens. Barnacles cement themselves to boats in the same way: proteins, lipids, and enzymes are produced in different glands and combined together via separate ducts.

The final cement product is thought to be a protein crosslinked with quinone. Sounds far out, but here's a schematic of just what those barnacles are up to:

Here's what the final crosslinked protein looks like, squiggly lines and all:

It's also interesting to note here that one of the many side products produced during this process reacts with metals like iron.

Finally

Where does all this lead? Applications of course! Barnacles, whether they like it or not, are going to help us make better adhesives so we can make better composites. Detailed applications include particle board adhesives and dental glue.

And don't stay out in the water too long next summer. At least Jaws lets go at some point!

Thanks to Emery Shier for providing his paper entitled "Protein Adhesives: Barnacle Cement".