Fire is good for cooking steaks and making iron bend and dancing around if you are tripping balls, but when it causes, say, your sleeping bag to burst into flame because a spark touched it, well, that is where flame retardants start to become real useful. The problem with a lot of flame retardants, though, is that they are made out of gnarly stuff that makes people worried about themselves and frogs. It is therefore kind of awesome, and not a little freaky and surprising, that you might be able to make a flame retardant out of DNA from fish sperm.
The first step to discovering this was, naturally, the gathering of a lot of fish sperm. This is the sort of thing scientists do all the time anyway, just for kicks. They then isolated DNA from said sperm, dissolved it in water, and rubbed it on a cloth. After the cloth dried the scientists tried to set the thing on fire, and it. Didn’t. Burn.
DNA’s chemical structure makes it ideal for the flame-stopping job. When heated, its phosphate-containing backbone produces phosphoric acid, which chemically removes water from cotton fibers while leaving behind a flame-resistant, carbon-rich residue. The nitrogen-containing bases release ammonia — which dilutes flammable gases and inhibits combustion reactions — and can act as “blowing agents,” which help turn the carbon-rich deposits into a slow-burning protective layer. Ultimately, these ingredients stop combustion by forming either a carbon-rich foam, or a protective, glassy carbon coating called char.
If it turns out that fish sperm is indeed a viable commercial flame retardant, it will be in very high demand. This means, of course, that another industry will not be far behind: fish porn.
Cloth Coated in Fish Sperm DNA Doesn’t Burn, smithsonian.