From Alzheimer’s to Zebrafish: Eclectic Science and Regulatory Stories 128
Spider webs have been used as dressings for wounds and even as fishing nets, but
the silk itself has found employment only as cross hairs in optical instruments.23 This
historical lack of use is about to change. As mentioned above, spider silk has the unusual
combination of high strength and extensibility, characteristics unavailable in synthetic
materials. Now that there is a greater understanding of the protein composition, the spin-
ning process, chemistry and physical properties and the genetic sequence, it is more likely
that silks will be used in a number of applications.24
Molecular biologists at the University of Wyoming are planning to use the proteins
from super-strong dragline silk to build artificial tendons and ligaments. The researchers
needed more silk than they could harvest from spiders in captivity, so they genetically
engineered goats to produce the proteins in their milk.
After the silk proteins are extracted and purified, a machine spins them into the
needed fibers. Researchers at the University of Notre Dame have genetically engineered
silkworms to produce spider webs, a process that began by inserting spider DNA into
ordinary silkworms. After the silkworms spin cocoons to develop into moths, scientists
interrupt the process. The cocoons are boiled in water and the silks are extracted from
their bodies.25 Spider silks are biocompatible, and someday may replace autogenous grafts
for tendon and ligament repairs.26
Final Thoughts
There are 40,700 described species of spiders and most spin multiple types of silk. Thus, it
has been estimated that some 200,000 unique silks may be available for investigating—an
amazing breadth of material properties.
One that has been examined is derived from Caerostris darwini (Darwin’s bark spider).
This spider constructs its giant orb web (up to 2.8 m2) suspended above streams, rivers
and lakes. It attaches the web to substrates on each river bank by anchor threads as long as
25 meters. This dragline silk exhibits an extraordinary combination of high tensile strength
and elasticity previously unknown for spider silk. The silk is more than twice as tough as
any previously described silk, and more than 10 times stronger than Kevlar. It may be the
toughest known biomaterial.27 It is likely other silks remain to be discovered with other
novel and exceptional properties.
References
1. The Earthlife Web. Accessed 30 March 2011. http://www.earthlife.net/chelicerata/arachnophobia.html.
2. Ibid.
3. Selden PA and Penney D. “Fossil Spiders.” Biological Reviews, November 2009 85:171-206.
4. Platnick NL. “The World Spider Catalog,” Version 9.5. American Museum of Natural History. Accessed 30
March 2011. http://research.amnh.org/entomology/spiders/catalog/index.html.
5. Murawski DA. Spiders and Their Webs. National Geographic.
6. Vollrath F. “Spider webs and silks.” Scientific American, March 1992:266:70-6.
7. Op cit 6.
8. Editorial: “Spider webs.” Discover, September 2010, p. 23.
9. Swanson BO, et al. “The Evolution of Complex Biomaterial Performance: The Case of Spider Silk.” Integrative
and Comparative Biology, May 2009 49(1):21-31.
10. Op cit 10.
11. Op cit 9.
12. Op cit 7.
13. Op cit 9.
14. Op cit 10.
15. Op cit 7.
16. Ibid.
17. Omenetto FG and Kaplan DL. “New Opportunities for an Ancient Material.” Science 2010 329:528-31.
18. Op cit 4.
19. Op cit 10.
20. Op cit 4.
21. Op cit 18.
Spider webs have been used as dressings for wounds and even as fishing nets, but
the silk itself has found employment only as cross hairs in optical instruments.23 This
historical lack of use is about to change. As mentioned above, spider silk has the unusual
combination of high strength and extensibility, characteristics unavailable in synthetic
materials. Now that there is a greater understanding of the protein composition, the spin-
ning process, chemistry and physical properties and the genetic sequence, it is more likely
that silks will be used in a number of applications.24
Molecular biologists at the University of Wyoming are planning to use the proteins
from super-strong dragline silk to build artificial tendons and ligaments. The researchers
needed more silk than they could harvest from spiders in captivity, so they genetically
engineered goats to produce the proteins in their milk.
After the silk proteins are extracted and purified, a machine spins them into the
needed fibers. Researchers at the University of Notre Dame have genetically engineered
silkworms to produce spider webs, a process that began by inserting spider DNA into
ordinary silkworms. After the silkworms spin cocoons to develop into moths, scientists
interrupt the process. The cocoons are boiled in water and the silks are extracted from
their bodies.25 Spider silks are biocompatible, and someday may replace autogenous grafts
for tendon and ligament repairs.26
Final Thoughts
There are 40,700 described species of spiders and most spin multiple types of silk. Thus, it
has been estimated that some 200,000 unique silks may be available for investigating—an
amazing breadth of material properties.
One that has been examined is derived from Caerostris darwini (Darwin’s bark spider).
This spider constructs its giant orb web (up to 2.8 m2) suspended above streams, rivers
and lakes. It attaches the web to substrates on each river bank by anchor threads as long as
25 meters. This dragline silk exhibits an extraordinary combination of high tensile strength
and elasticity previously unknown for spider silk. The silk is more than twice as tough as
any previously described silk, and more than 10 times stronger than Kevlar. It may be the
toughest known biomaterial.27 It is likely other silks remain to be discovered with other
novel and exceptional properties.
References
1. The Earthlife Web. Accessed 30 March 2011. http://www.earthlife.net/chelicerata/arachnophobia.html.
2. Ibid.
3. Selden PA and Penney D. “Fossil Spiders.” Biological Reviews, November 2009 85:171-206.
4. Platnick NL. “The World Spider Catalog,” Version 9.5. American Museum of Natural History. Accessed 30
March 2011. http://research.amnh.org/entomology/spiders/catalog/index.html.
5. Murawski DA. Spiders and Their Webs. National Geographic.
6. Vollrath F. “Spider webs and silks.” Scientific American, March 1992:266:70-6.
7. Op cit 6.
8. Editorial: “Spider webs.” Discover, September 2010, p. 23.
9. Swanson BO, et al. “The Evolution of Complex Biomaterial Performance: The Case of Spider Silk.” Integrative
and Comparative Biology, May 2009 49(1):21-31.
10. Op cit 10.
11. Op cit 9.
12. Op cit 7.
13. Op cit 9.
14. Op cit 10.
15. Op cit 7.
16. Ibid.
17. Omenetto FG and Kaplan DL. “New Opportunities for an Ancient Material.” Science 2010 329:528-31.
18. Op cit 4.
19. Op cit 10.
20. Op cit 4.
21. Op cit 18.