Spider Silk: Lighter than Cotton, Stronger than Steel

Did you know that spider silk is lighter than cotton but stronger than steel? Despite being a tougher and more versatile material than some of the most advanced synthetic fibers, spider silk has yet to be fully harnessed for human applications.

This article seeks to spread the potential of spider silk, delving into its unique properties, the fascinating biology behind its creation, and the future it holds for revolutionizing fields from medicine to materials engineering.((https://www.sciencedirect.com/topics/engineering/spider-silk))

What is Spider Silk?

Spiders spin a protein fiber known as spider silk, which they use to make egg sacs, build webs, catch prey, and travel by ballooning.((https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2658765/))

The production of spider silk is also a marvel of biology. Spiders have specialized glands that secrete the silk protein, which is initially liquid. As the spider spins, the liquid protein solidifies into fiber through a process that is not yet fully understood but is known to involve the pulling and stretching the protein chains.

Spider silk, a product of nature’s intricate engineering, is a testament to the wonders of nature that are often hard to copy.

Properties of Spider Silk

1. Light and Thin, Yet Strong: Spider silk is incredibly lightweight and much thinner than human hair, even thinner than cotton. Despite this, it’s exceptionally strong.((https://www.labiotech.eu/trends-news/airbus-amsilk-spider-silk-planes/))
2. Surviving Tough Conditions: Spiders rely on the strength of their silk for survival. It must be tough to hold against the struggles of trapped insects and harsh weather conditions like wind and rain.
3. Comparing with Familiar Materials: To understand spider silk’s strength, it’s compared to materials we know. Surprisingly, spider silk is stronger than steel when you compare them based on their weight. Although spider silk isn’t as stiff as steel, it has a similar ability to withstand pulling forces (tensile strength) and is better when comparing strength relative to its density.((https://www.smithsonianmag.com/science-nature/fourteen-ways-spiders-use-their-silk-180978354/))
4. Spider Silk vs. Other Materials: Spider silk is five times stronger than steel of the same diameter. It is almost as strong as Kevlar, the toughest man-made polymer.((Spider Silk (bris.ac.uk))) Spider silk has a higher ability to absorb energy before breaking (higher fracture toughness) than Kevlar.((https://www.treehugger.com/captivating-facts-about-spider-silk-4868351))
5. Elasticity and Temperature Resistance: Spider silk can stretch four times its original length without breaking. It also maintains its strength in extremely cold temperatures, below minus 40 degrees Celsius.((https://www.degruyter.com/document/doi/10.1515/epoly-2020-0049/html?lang=en))
6. Hypothetical Strength: There’s a suggestion (not tested in reality) that a strand of spider silk as thick as a pencil could potentially stop a large airplane mid-flight.
7. Real-World Example: The Darwin’s bark spider in Madagascar creates some of the largest spiderwebs in the world. These webs can stretch up to 25 meters across rivers, showcasing the incredible length and strength of the spider silk.((https://www.justspiders.com/darwins-bark-spider))

Potential Use of Spider Silk

Its complex molecular structure sets spider silk apart, which allows it to be both stretchy and strong simultaneously. This unique combination of properties has made it a subject of intense study in material science, with researchers exploring its potential applications in various fields such as biomedicine, textiles, and even military armor.((https://www.news-medical.net/life-sciences/Role-of-Spider-Silk-in-Biomedicine.aspx)),((https://www.bodyarmornews.com/spider-silk-is-now-being-used-to-make-body-armor/)),((https://www.militarytimes.com/opinion/commentary/2021/02/23/spider-silk-research-from-bone-regeneration-to-bulletproof-vests/))

Despite its remarkable qualities, harvesting spider silk on a large scale is challenging due to spiders’ territorial and cannibalistic nature, making farming difficult.((https://www.sciencedirect.com/science/article/pii/S1369702111700578)) This has led to research into the synthetic production of spider silk using genetically modified organisms.

Challenges in Producing Spider Silk

Even though we’ve known what spider silk is made of for a while and managed to copy the spider silk gene into other organisms like plants, bacteria, silkworms, and even goats, making perfect spider silk has been hard. The silk these organisms produce isn’t quite the same as real spider silk because they don’t have the special tools (spinnerets) that spiders do to make silk. So, scientists have to make the silk themselves, and it’s not as complex as the silk from spiders.((https://www.treehugger.com/captivating-facts-about-spider-silk-4868351))

But there’s hope! After a lot of effort, it looks like we’re getting closer to being able to make synthetic spider silk.((https://scitechdaily.com/the-future-of-sustainable-clothing-new-breakthrough-in-synthetic-spider-silk-fabrication/)),((https://newatlas.com/materials/synthetic-spider-silk-stronger-tougher/))

Several companies can now produce spider silk proteins using bacteria, yeast, and silkworms, and they’re using this silk in products like skin lotions and medical devices. Scientists are optimistic about achieving strong materials from spider silk, like bulletproof vests. At the time of writing, we’re getting closer.