Columns

Healing Powers of the Web

By Michael Barbella, Managing Editor | September 20, 2016

Prof. Fritz Vollrath is utterly baffled by the concept of arachnophobia.

His bewilderment is somewhat ironic, considering he’s the world’s foremost spider expert, having studied the hairy, eight-legged creatures longer than any other person on the planet. Vollrath’s field research has taken him around the world—with long stints in Panama and Papua New Guinea—to track exotic species with rare qualities, and down some rather unconventional paths—feeding the invertebrates drugs and training them with tuning forks—to better understand their web-spinning talents. He once even “taught” a spider to write the number “88” in silk by manipulating the orientation of its web while the insect worked its magic. 

“I don’t understand arachnophobia,” Vollrath recently told journalists visiting his makeshift rooftop greenhouse at the University of Oxford in the United Kingdom, where the zoologist breeds his favorite species—the golden orb weaver. “Spiders have been around for millions of years. There is so much more to learn from them.”

Vollrath’s own tutelage began in 1972 in Munich, Germany, after discovering the lightweight, high-tensile designs of renowned architect and Pritzker laureate Frei Otto in the city’s newly constructed Olympic Park. Built to mimic spider webs, the park inspired Vollrath—a neurophysiology graduate student at the time—to explore the unique properties and functions of spider webs.

“The web is a complex, geometric structure, and the spider builds it, from itself, with very fine material,” he noted to CNN. “You think, ‘How does that work? What rules does the animal use?’”

To answer those questions, Vollrath worked with architects to design buildings based on webs (e.g., Pavilion of the Future in Seville, Spain), and nets for catching space debris. He also accepted commissions from the U.S. military to study the effects of drugs, including LSD, on a spider’s web-building capabilities (fun fact: caffeine makes the insects nervous).

Yet none of those web-inspired applications hold as much promise for mankind as those in the healthcare arena. In the course of his studies, Vollrath unlocked the secret to spider webs’ mystical healing powers: Upon examining spider silk’s nanocomposition, Vollrath found a molecular peptide that helps give the sticky substance its orderly structure. This peptide—similar to a recurrent motif, or a musical melody—also exists in the filaments that hold human cells together. Consequently, when human cells encounter spider silk, they recognize this shared “motif” or melody, and react by attaching to the silk and growing along with it.

Such molecular harmony could have profound implications. Spider silk dressings have already been tested on animals and have performed flawlessly, blending seamlessly within host tissue. Vollrath and his Silk Group team at Oxford also have created a small, beating heart muscle using a certain kind of silk and cardiac cells.

In addition, the Group—through several spinoff companies—is experimenting with a spider silk-inspired material it developed called Spidrex for use in vascular grafts as well as nerve and cartilage repair. The substance is harvested from silkworms (the creature’s silk has a similar molecular structure to spider dragline silk), dissolved to remove its toxic glue, and then reconstituted as a tough, clean material.

One of the spinoff firms, Orthox, has used Spidrex as the basis for a more mall-eable material that can be shaped into knee cartilage and simultaneously serve as a biocompatible scaffold to encourage new cell growth. The substance, called FibroFix, is made from fibroin (the major component of silk) using the same conditions spiders use when spinning their webs.

Orthox has developed two different FibroFix implants. One is designed to replace the knee’s meniscal cartilage, while the other treats damage to the articular cartilage by resurfacing the area at the end of the bone. The implants—composed of 15 percent fibroin and 85 percent holes filled with water—are halfway through human clinical trials and could be widely available by 2018, according to a CNN report.

“Spider silk is 25 times as tough as high-tensile steel weight for weight. When you think about cartilage, its function is to be a tough resilient material. It does the job of shock absorbing and force displacement,” Orthox CEO and Chief Scientist Dr. Nick Skaer told Britain’s The Guardian last summer. “What we are trying to do is first and foremost prevent knee joints from deteriorating by repairing the cartilage in the first place, but once they have deteriorated, giving the patient a strategy which is not an all-or-nothing, one-time shot which you can only have at the latter end of your life when you are less active and you will be damaging the implant and the surrounding foundation to a lesser extent.”

A scaffold similar to the FibroFix structure is currently under development for nerve repair through a third Oxford University offshoot (Neurotex). Vollrath’s team intends to apply the technology to the central nervous system to help reverse paralysis caused by severe spinal injuries. About 282,000 Americans are living with such an injury and statistics indicate 17,000 new cases are diagnosed annually.

“There’s a lot of interest in the medical community in silks...” Vollrath said. “We can fix a nerve that’s been crushed, we can connect the two ends with a sheath that’s filled with spider silk and the nerves will grow along these spider silk threads and connect...I don’t see at this stage anything that would be off-limits.”  

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