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• Exact sequence and structure unknown (at least unpublished)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?