We produce about one gallon of it every day. It covers 2,000 square feet of our bodies. And it plays a crucial role in lubricating our movements and protecting against disease.
This miracle substance? Mucus.
Mucus plays all sorts of vital roles in our lives, and yet it's a surprisingly undervalued resource, says Katharina Ribbeck, a professor at MIT and a leading mucus researcher.
"We think about skin as the main barrier, but it's only about two square meters," she says. "Mucus goes unnoticed because we know it as snot typically, and most of its function is internalized."
Ribbeck's lab is trying to uncover what makes mucus so special, and how we might potentially synthesize it and apply it. Artificial versions of mucus could eventually become alternatives to antibiotics and have a range of industrial uses, like keeping ship hulls free from "biofouling"—damaging build-ups of natural material on wet surfaces.
Her research focuses on mucin polymers that are thought to give mucus its qualities. "When microbes team up, they can produce toxins at much higher concentrations and become difficult to manage by the immune system," Ribbeck explains.
"To achieve that they need to communicate with one another. One of the effects of the mucins is to dampen that communication. It's like they keep kids in different rooms and close the door, so they can't cause so much damage."
Rather than killing microbes, as antibiotics do, mucins seem to keep our good and bad microbes in balance. That means that bacteria are less likely to develop resistance, always necessitating new, stronger drugs. "We don't want to kill, we want to work with what we have and find an equilibrium," she says. "We want to stabilize microbes in the context of human health without them becoming virulent."
Ribbeck imagines us taking mucus like prebiotic foods, perhaps in toothpastes or mouthwashes, or mucins being integrated into biomedical equipment, so it doesn't become covered in hard-to-remove biofilms.
But that may be a few years away yet. Because of their complexity, creating artificial mucins is very hard, Ribbeck says. "We are thinking of strategies to make them. The critical question is how much of their structure do we need? Do we need the exact chemistry or just some part of it? It will require basic science, but also creative chemistry to move ahead."