You may have heard of the saying “spider silk is stronger than steel,” but scientists didn’t find a practical use for this fact until recently. Spider silk has always been a desired material for creating garments and clothing, but the animals’ cannibalistic nature made it difficult to farm their silk in large quantities. Furthermore, directly extracting silk from wild spiders is also extremely inefficient — one would need 400 spiders to create 1 square foot of cloth.
What’s So Great About Spider Silk?
After over 300 years of evolution, spiders have perfected the ability to create spider webs to capture insects. There are 8 different types of spider silk, all of which have different protein structures and functions. Dragline silk is the perfect combination of sticky, stretchy, and strong, which is a quality difficult to find in many modern materials. In the wild, spiders use this type of silk to build a base for their webs along with using it as a safety line when climbing around their environment.
The secret for dragline silk’s unique properties lies in its protein makeup — the silk is made up of alternating sections of elastic and crystallized proteins, giving it both flexible and durable qualities. Scientists view dragline silk as the “ideal” type of spider silk, which they are currently trying to mimic synthetically.
Biomimicry of Spider Silk
Biomimicry is the imitation of natural phenomena in the lab, which in this case is spider silk. It is extremely difficult to build proteins from scratch, so many researchers are attempting to modify the DNA of other animals to produce the desired protein. CRISPR, short for Clustered Regularly Interspaced Short Palindromic Repeats, is a gene editing technique that allows for scientists to selectively modify the DNA of a living organism. This tool is used in the production of synthetic spider silk, and these are a few of the host organisms used:
Bacteria/Yeast
The spider gene that codes for silk production is first inserted into the DNA of the host using CRISPR technology. The microorganism produces a solution full of the spider silk protein, which is then stretched into thin strands and spun, which crystallizes the proteins. This method is particularly useful for the mass production of synthetic spider silk, since bacteria and yeast are easy to grow in large quantities. However, the silk needs to be spun mechanically, which is very time consuming.
Silkworms
Just like with yeast and bacteria, the gene that codes for spider silk proteins is inserted into the silk glands of silkworms via the CRISPR tool. The benefit of using silkworms is that the silk can be automatically spun by the animal, but the produced silk isn’t as strong in comparison to spider silk. Silkworms are also susceptible to disease, making it risky to farm them in large quantities.
Downsides to Synthetic Spider Silk
It is impossible to create synthetic spider silk that is identical to the spider silk that is directly extracted from spiders. Real spider silk is made of alternating sections of flexible and hard proteins, but the amino acids themselves have a randomness that cannot be achieved by science — the closest we can get is repeating a section of the spider silk protein DNA. We also don’t know if the genes inserted by CRISPR will pass on to future generations, or if re-insertion is required for each generation of host organisms.
Future Plans for Implementation
Synthetic spider silk is a relatively new invention, so it is still in the early stages of research. As more experiments are being conducted, humanity will slowly be able to resolve the issues noted above.
Aside from being lightweight, flexible, and durable, spider silk is also sterile and biocompatible. This means that the silk has antibacterial properties, allowing it to be used around skin, organs, and other parts of the human body without much risk of infection. Scientists hope to take advantage of this property by using spider silk to weave bandages for wounds, repair tendons, and manufacture coatings for silicone implants. Furthermore, the fact that spider silk is biodegradable gives researchers hope of replacing plastics with this material in the future.
References
“Biomimetics: Engineering Spider Silk – USC Viterbi School of Engineering.” Illumin, 1 Nov. 2009, illumin.usc.edu/biomimetics-engineering-spider-silk/.
European Patent Office. “Thomas Scheibel - Artificial Spider Silk.” YouTube, 24 Apr. 2018, www.youtube.com/watch?v=Bb_vkS_Zlpw. Accessed 14 Oct. 2024.
Kowalski, Kathiann. “How to Spin Synthetic Spider Silk.” ScienceNewsExplores, 30 Jan. 2017, www.snexplores.org/article/how-spin-synthetic-spider-silk.
Salehi, Sahar, et al. “Spider Silk for Tissue Engineering Applications.” Molecules, vol. 25, no. 3, 1 Jan. 2020, p. 737, www.mdpi.com/1420-3049/25/3/737?
type=check_update&version=1, https://doi.org/10.3390/molecules25030737.
“Spinning Artificial Spider Silk into Next-Generation Medical Materials - American Chemical Society.” American Chemical Society, 2024,
TEDx Talks. “The Spiderman Technology - Vision or Nonsense? | Thomas Scheibel | TEDxMünchen.” YouTube, 20 Dec. 2017, www.youtube.com/watch?v=7V-SP3I7q9Q. Accessed 20 Jan. 2022.
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