Spider Unchained 2: Demystifying Spider Silk

     After having my interest piqued last week by my worst nightmares, the silk-spinning arachnids have seemed to find me again.  While there were a plethora of other articles that I would have normally found more interesting (and less terrifying), such as lifelogging and the largest prime number (I couldn't care less, but I know some may), my previous entry on silk extraction and "spider slavery" really made this well-timed news release more interesting than the rest.  So, I present to you the blockbuster sequel that nobody's been waiting for:

In theaters never.

     With all silliness aside, the recent discovery by post-doctoral scholar Kristie Koski of a new technique for examining spider silk is big, and oozes tremendous potential.  Originally reported by Stanford University, Koski described this process of examining the properties of a spider web, as it is being spun, without disturbing the spider or its creation at all on the Nature Materials journal on January 27th, 2013.  A member of the Materials Science and Engineering Department at Stanford, Koski's new findings are a result of a near-100-year-old spectroscopy technique, Brillouin spectroscopy.  Termed as "scattering," this technique has a laser shone on the spider web, creating sound waves from its light, which reflects light waves back to the spectrometer.

     The spectrometer measures the reflected light to determine the tension of the silk where the light originated.  Various measurement types can be employed, as Koski was able to measure single strands, intersections of multiple strands, or the "glue spot" where a strand(s) connects to another.  To highlight the significance of this "new" technique, Stanford uses a striking analogy about how the old techniques, only able to gauge two of the five elastic constants of spider silk, were equivalent to only measuring steel beams and cables and "trying to extrapolate conclusions about the strength of a bridge."  Now, this is all nice, sure, but what was discovered?

     Of all of the findings within Koski's experiment, the biggest is the fact that the web's stiffness is not homogeneous; it varies throughout the intersection points, glue spots, and other locations.  The belief prior to this was that all of the material in spider's silk was uniform, so this is quite ground-breaking.  While not as ground-breaking per se, the further exploration of supercontraction is a very interesting aspect of this discovery.  Koski found that when humidity is high, spider silk absorbs water and non-secured fibers shrink to nearly 50% off their original size.  The big question about supercontraction pertains to why nature would "give" the spider's silk this property, considering its web is its most vital key to survival.

A spider web closely examined with Koski's spectroscopy
technique (right).

     Scientists have begun debating about supercontraction since its discovery, and have concluded three theories to solve this natural riddle:

1. Supercontraction is an inherent trait of silk, not necessarily related to the spider's evolutionary lineage.
2. Supercontraction allows the spider to customize its web as it spins it, adjusting it to withstand various  
    environmental factors and using the water to contract or expand parts of its web.
3. Supercontraction makes the silk tighter, thus preventing heavy rain droplets to destroy the spider's web entirely.

     Out of all of these findings, there is so much that is remarkable.  Whether it be that spider webs can now be examined without disturbing their webs (we're already enslaving them after all J) or that hydration can affect spider silk's strength or that I'm writing another article about my archnemesis in this universe, there is no denying that Ms. Koski has struck gold with this discovery, or more specifically silk.  It is only a matter of time before this research is unified with the innovations already made in part by spider silk, and these eight-legged creatures are responsible for the materials we use.  Until next arachnid article! Stay silky.