March 26, 2024

Audrey Tran

11th Grade

Fountain Valley High School

A Remarkable Material

Stronger than steel yet thinner than human hair, spider silk remains a fascination and a mystery to scientists. With its high tensile strength, flexibility, and lightweight nature, this natural fiber can be used for textile and material purposes, and its biodegradability and biocompatibility present much potential in medical applications. Spider silk’s unique properties make it an attractive biomaterial that researchers have been seeking to replicate, however, there has not been a successful nor sustainable attempt that can be practically scaled for commercial purposes.

Properties of Spider Silk

Spider silk consists of proteins called spindroins which are large chains of proteins with repetitive sequences; the primary amino acids being glycine and alanine. These repetitive sequences are what allow for the strong, elastic qualities of spider silk. Spindroins are dissolved in a liquid solution called dope which is then spun into as dry fiber as it leaves the spider’s abdomen through spinnerets. At the same weight, spider silk is five times stronger than steel and can be stretched to 30 percent past its current length without breaking. Furthermore, spider silk has the ability to absorb great impact forces as spiders use it in nature to catch its prey like flies, moths, and even birds. It also is advantageous in extremely high and low temperatures, withstanding temperatures from -40 to 200 degrees Celcius. 

Possible Applications of Silk

Spider silk has been used by humans for thousands of years: The Ancient Greeks used spider silk as bandages to stop bleeding and the Aborigines used cobwebs as fishing lines and nets. Currently, scientists are fascinated by the potential use of spider silk in textiles, imaging, robotics, medicine, and many more applications as its unique characteristics far surpass any natural or man-made material. 

1. Textile:

Spider silk is light and breathable while extremely durable. Its properties pose a great potential to be used to make wear-resistant clothing, parachutes, or armor. In 2009, an 11-by-4-foot tapestry was weaved entirely from spider silk. The project was extremely laborious and required the silk from one million spiders.

2. Imaging:

Some proteins in spider silk are arranged in crystalline structures which allow for transparency and its ability to focus light. The fibers of spider silk can be used to create super lenses for optical instruments. When shining a laser through the super lens, researchers can observe especially small structures like viruses, germs, and cell structures. Scientists have been able to create super lenses from spider silk to produce high-resolution images of inside the human body.

3. Robotics: 

Spider silk when exposed to sufficient humidity, twists and contracts, producing a strong torsional force. The force produced by the twisting reaction can utilized for microactuators, devices that can move a system such as opening or closing valves. The sensitivity of spider silk to humidity can also be used in sensors.

4. Medicine:

The biodegradability and biocompatibility of spider silk make it an attractive alternative material for sutures and regenerative medicine. This biomaterial has a minimal immune response and the products of its decomposition are compatible with the human body. Its thin yet strong nature makes it an excellent candidate for suturing delicate structures like arteries and repairing tendons or ligaments.

Difficulties of Producing Spider Silk at Large Scale

For years, scientists have sought to mass-produce spider silk. Harvesting natural spider silk through farming spiders like silkworms has proven to be inefficient and tedious. Spiders, being cannibalistic and territorial creatures, are incredibly difficult to domesticate and tend to produce less silk in captivity. Due to this, milking spiders for their silk at the commercial level has been concluded to be unrealistic and improbable. 

Thus, many researchers have looked to design a synthetic material that mimics the properties of spider silk: lightweight, durable, and flexible. Bacteria and other transgenic organisms (organisms that contain DNA introduced artificially from another organism) have been genetically engineered to express natural spider silk genes and produce spindroins. Yet these spinroins aren’t exactly identical to that of spiders and scientists found that they are not soluble in water like the dope spiders produce. This also leads to the practical issue of spinning said dope into silk. Thus, currently, no exact replica of spider silk has been designed because not enough knowledge is known about the spidroin encoding genes or the biological process of spinning dope into a solid fiber.

The extraordinary properties of spider silk remain a unique material that can only engineered by nature. With further research and experimentation, the mass production of synthetic spider silk will revolutionize numerous of industries.