Spider Silk
Dawson Bausman
March 28, 2002
• Variations
• Golden Orb Web Weaver
Spider Silk
• Where does it come from?
• What is it?
• What are its advantageous properties?
• How can it be mass produced?
• What are the applications?
Where does it come from?
The seven glands are: • Ampulleceae major and minor for walking
threads and dragline • Pyriformes for the attaching threads • Aciniformes for encapsulating prey • Tubiliformes for the silk of the egg-sac • Coronatae threads for the axis of the sticking
threads • Glandula aggregata for the sticky binding
material
Silk Releasing Tubes
• 100-50,000 tubes
• Strands as small as 20 nanometers
• Each fiber only 4 to 5 microns in diameter
• Entire strand about 15 to 20 microns in diameter
What is it?
• 30% to 45% crystalline
What is it?
• More than 50% of silk is a polymerized protein called fibroine.
What is it?
• Exact sequence and structure unknown (at least unpublished)
• Main contents are 7 natural Amino Acids
• Alanine and Glycine
• Glutamine, Leucine, Arginine, Tyrosine, Serine
What is it?
• 2 Alanine rich proteins embedded in a jelly like glycine rich polymer
• 1 protein is highly ordered crystalline, other is not ordered. These proteins give toughness.
What is it?
• How can proteins compete with Kevlar???
Advantageous Properties
• Tailorable Properties
Advantageous Properties
Normal 5x 20x
Diameter
• Average is .15 mm
• Smallest Measured is .02 mm
• Human Detection
• Insect Detection of the web
Advantageous Properties
• Coated with antiseptic agents (pyrolidin, potassium hydrogen phosphate and potassium nitrate)
• Process proteins from water based solutions
• Water
Water
Mechanical Properties
• Inelastic or Elastic
• Tough at low temperatures
• Tensile Strength of 400,000 lbs / sq. in
• 25% lighter than other synthetic petroleum based fibers
• Specific Strength
Spider Silk
0
200400
600
800
10001200
1400
1600
0 100 200 300 400 500
Strain (%)
Str
ess
(M
Pa
)
Nature vs. Man
• Nature is uncertain and slow
• Farming is not possible
Mass Production
• 22,000 base pairs to the genetic sequence
• Believed to only need 300 of these pairs
Mass Production
• Plants, Fungi, Bacteria
• Mammals
Webster and Pete
Stress Strain
Draw Ratio
Uses
• Past – WWI Cross hairs, Tribal uses
Uses
• Medical - sutures, tendons, ligaments– $10,000/gram
Uses
• Textile Industry
Automotive Industry
Bullet Proof Vests
Space Station Coatings
Biodegradable Fishing Line
Spider Man
Conclusions:
• Spider Silk is an excellent tailorable fiber material
• There is quite a bit of work yet to be done to perfect the process of making silk
• There are many potential applications of silk
Acknowledgements:
• Jeffery Turner and Chantal LaRouche of Nexia Biotechnologies
• David Knight and Fritz Vollrath of Oxford University
• Randy Lewis of the University of Wyoming
QUESTIONS?