Marlene Andersson didn’t need a bite from a radioactive spider to spin spider silk, she made it herself through ground-breaking biochemical research. Spider silk is one of the toughest materials on the planet. It’s strong, yet flexible and has been used in traditional medicine for centuries. It also has wound healing properties and can be implanted into living tissue without an immune response, making it of particular interest for regenerative medicine.
Farming spider silk is almost impossible (spiders are territorial and cannibalistic) so for decades researchers have puzzled over how to create it artificially. Researchers are able to produce the spider silk proteins using bacteria, but no one was actually able to spin fibers that resemble those made by spiders—until Marlene came along. During her PhD in medical biosciences at the Swedish University of Agricultural Sciences, Marlene researched the molecular mechanisms of spider silk formation and developed a method to spin artificial spider silk.
Spinning artificial spider webs required Marlene’s knowledge of biochemistry, protein biochemistry, cell biology, and histology. Spider silk is made of protein fibers and different types of silk are used for different parts of the web. The silk proteins are produced in the spiders’ abdominal glands, and they use different glands to produce different types of silk. Marlene’s project focused on the major ampullate gland, where what’s called “dragline” silk is produced. It is three times as tough as Kevlar, the material we use to make bulletproof vests. Spiders use it for the outer rim and spokes of their webs, as well as the thread they dangle from. While studying the major ampullate gland, Marlene found that the silk proteins come together to form a solid fibre in response to changing pH levels. This was a key step in understanding how spiders spin their silk.
Armed with this information, Marlene and her coworkers set out to spin artificial spider silk. They grew silk proteins in bacteria, purified them, and then gathered a large concentration of proteins in an artificial gland made of glass capillaries. By mimicking the pH gradient of the major ampullate gland in the capillaries, Marlene and her colleagues were able to create long, continuous fibers and spin artificial spider silk.
Artificial spider silk could have some exciting applications in regenerative medicine. Spider silk has wound healing properties which would make artificial silk the perfect material to develop wound healing patches with. Because the fibres are so strong and can be implanted into living tissue without rejection, it has huge potential for nerve regeneration or artificial tendons. It might even be possible to one day make artificial human organs out of spider silk.
Marlene’s interest in spider silk can be traced back to her childhood desire to work with animals. When she was younger, she wanted to become a veterinarian before attending an inspiring presentation by a group of scientists. She realised that she didn’t want to work directly in animal care, instead she wanted to analyse the animals’ maladies. Her current research does require some hands-on animal care of the eight-legged variety. In a task that’s not for faint of heart, Marlene handles spiders to better understand just how they spin their silk. They’re Swedish spiders for the most part with the occasional golden-web-spinning Florida variety (google “golden orb spider”).
Spiders might not be everyone’s cup of tea, but Marlene was interested in her PhD project from the moment she saw the posting. “When this position came out I had my eye on the project for a while. I thought it was a really ‘sexy’ position.” The position lived up to her expectations even if it didn’t always go as planned. “As soon as I started I realized that the project never goes as you have planned. It always takes new directions and as soon as you have published one result, you realize you have to do something other than what you thought.” But without this process, Marlene couldn’t have achieved the results that she did, and it’s doubtful that someone else would have been able to accomplish the same results. “A research position is very personal. The results would look completely different if there was another person doing my job.”
Although she is not actually a superhero, Marlene does have some idea of what it feels like to have super powers. “For me it happened in the lab when suddenly we could spin our own spider web. It was an amazing feeling that nothing can compare to!” The feeling of working for herself and no one else also motivates Marlene, since so much of a PhD is self-directed. When she first started her doctorate she often worked in a research group, but as she progressed she became more independent. She doesn’t want to succeed just to impress her boss, she wants to succeed for herself and to advance the world.
Take that Marvel!