Underwater Bugs in Medicine - Caddisfly Silk Inspires Scotch Tape Solution for Surgeries

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Image via University of Utah, credit Fred Hayes for the University of Utah

This is a caddisfly larva, or a rock roller as it is also known. It's a strange little bug that while in larva state, lives underwater and creates its own "shell" by spinning a sticky silk that collects sand grains. Scientists are using this as an inspiration for a biomimetic solution in surgery, hoping to create a synthetic version that can be used as an adhesive tape-like suture. According to University of Utah researchers, the silk is sticky when wet and they've finally figured out why. Using this information, they just might be able to develop a great solution for surgery situations.

Russell Stewart, an associate professor of bioengineering and principal author of a new study on the fly's silk, states, "I picture it as sort of a wet Band-Aid, maybe used internally in surgery - like using a piece of tape to close an incision as opposed to sutures," he adds. "Gluing things together underwater is not easy. Have you ever tried to put a Band-Aid on in the shower? This insect has been doing this for 150 million to 200 million years."

The caddisfly larve create the silk from their spinnerets, weaving the sticky string around sand grains, sticks, pieces of leaves and other debris to create a tube that becomes their safe home while developing. Researchers started examining the silk and saw that the way the silk works is much like "using Scotch tape on the inside of a box to hold it together."

The researchers are now looking at the chemistry and structure of the silk, noting that there are phosphates used in the making of the silk - which makes it different from moth or butterfly silks - and that, along with electrical charges, are what makes it sticky while wet.

"These fibroin proteins that make up the silks are water-soluble because of the electrical charges. Ironically - and this is our hypothesis for now - the association of those plus or minus charges makes them water-insoluble. This is how you make a silk fiber under water."

The researchers are hoping to be able to copy the chemistry for use in medicine. It's not the first time flies help out in medical research, and we can bet not the last.