Elasticity of Spider Silk Explained

spider web

Scientists have discovered why the silk produced by a spider to make webs is so ‘elastic.’ This is because fragments of the silk’s protein threads act like a ‘super spring’, able to stretch to five times their initial length.

Spider silk is a protein fibre spun by spiders. The silk is used to produce webs, which act as traps for insects, nests or cocoons to protect offspring. Spiders also use the silk, which is incredibly strong, to suspend themselves.

The finding was serendipitous. The research group were examining a technique to measure pushes and pulls from proteins in living cells, as part of an exploration of cancer. As part of a check of the technique, they stumbled across the spider stretch mechanism.

Spider silk proteins are unusual. All other biological springs increase in length proportional to the force applied, and this lengthening is universally limited to 20 percent (in other words, the increase in size from stretching cannot be more than one fifth of the original size).

With spider silk, the length can increase by a whopping 500 percent. This was found using fluorescent labels to watch specific proteins via a fluorescence microscope.  The motion was detected using different forces.

The findings are published in the journal Nano Letters. The research is titled “Spider Silk Peptide Is a Compact, Linear Nanospring Ideal for Intracellular Tension Sensing.”

About the author

Tim Sandle

Dr. Tim Sandle is a chartered biologist and holds a first class honours degree in Applied Biology; a Masters degree in education; and has a doctorate from Keele University.