Electrospinning of hybrid polymers to mimic spider dragline silk

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Electrospinning of hybrid polymers to mimic
spider dragline silk

• Low Rui Hao
• Lim Yao Chong
• Tracey Atkinson
• Patrick Steiner

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IntroductionSpider Dragline Silk

• It is the material that makes up the main axels
  of orb-weaver spider webs.
• It has a High tensile strength and High
  extensibility.

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IntroductionSpider Dragline Silk

• It has a composite structure of
• 20 crystalline regions
• 80 highly elastic substances
• Extendible regions of the spider dragline silk
  connect crystalline regions to produce the
  amazing properties of the spider silk.

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IntroductionApplication

• Ranges from biomedical uses, such as ligaments
  and sutures, to bullet proof vests and
  parachutes.
• Spider silk is not widely used in the industry,
  because it is not readily available and there is
  no method to mass produce it. 
• However, the properties of the spider silk prove
  it is possible to replace materials such as
  Kevlar.

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BackgroundKeratin and Elastin

• Elastin
• A material that provides elasticity to artery
  walls, lung tissue, skin, ligaments, etc. 
• Biodegradable
• More elastic than spider silk

• Keratin
• a material that provides strength in biomaterials
  such as nails, bird beaks, horns, etc.
• Biodegradable
• Has same beta-sheet composition as spider silk

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BackgroundElectrospinning

• A polymer is dissolved in a volatile solvent and
  placed in a syringe.
• The solution is charged with a high voltage.
• The high voltage creates an electric field that
  causes the polymer to be spun out in thin threads
  (nanofibers) to a collector plate.
• A fibrous mat is formed.

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Objective

• To create fibrous electrospun mats with blended
  fibers, part keratin part elastin, to mimic the
  high tensile strength and extensibility of spider
  dragline silk.
• Blended fibers parallel syringes method
  (physical mixture)

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Hypothesis

• By combining Elastin and Keratin spun under
  optimal conditions into blended fibres in
  electrospun mats, a mat with tensile strength and
  extensibility similar to that of spider silk will
  be produced.

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VariablesConstants

• Polymers used
• Syringe pumps used
• Solvents used
• Solution size spun
• Power source
• Syringes used
• Cover for collector plate(aluminum foil coated in
  polyethyleneoxide PEO base mat)
• Spin time

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VariablesIndependent and Dependent

• tensile strength 
• extensibility 
• of the fibrous mat produced from the
  Electrospinning.

• The parameters of the method including
  electrospinning method variables
• distance to collector plate
• size of collector plate
• flow rate of jet
• voltage
• needle gauge
• and chemical variables of the mat
• concentration of the spun solution
• ratio of Elastin to Keratin

• Independent Variables 

• Dependent Variables

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Materials and apparatus usedApparatus

• Safety Goggles
• Lab Coats
• Power Source, up to 30 kV
• 5 mL syringes
• 22 gauge needles
• Pasteur pipettes
• 5 mL graduate cylinders(2)
• 50 mL beakers(2)
• Hot plates(2) for stirring
• 2 Small magnetic stir bars
• Aluminum Foil
• 3cm by 3cm collector plate

• Syringe Pump
• Timer
• Alligator Clip Wires
• Atomic Force Microscope
• Balance
• Scoopula
• 2 Glass Stir Rods
• Tensile Tester (external)
• Distilled Water
• Refrigerator

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Materials and apparatus usedMaterials

• 20 g of Polyethyleneoxide(PEO)
• 1 M hydrochloric acid, 1 L
• Elastin Powder, 20 g, Elastin Products Company
  Inc.
• Keratin 20 g, Advanced Scientific and Chemical
  Inc.
• Urea Powder, 120 g, Sigma Aldrich

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MethodologyPhases
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Preparation

• To dissolve Keratin and Elastin in suitable
  solvents to be used in Electrospinning
• To determine spin time of the respective
  solutions of Keratin and Elastin (estimation)
• To prepare a PEO coating on the collecting plate
  (ease of removing of mat)

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MethodologyPhases
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Optimizing Spinning Parameters for individual
polymers

• Optimize the conditions for electrospinning
  keratin and elastin individually
• distance to collector plate
• size of collector plate
• flow rate of jet
• voltage
• needle gauge
• The optimal conditions found will be kept
  constant in Phase 3 of the experiment

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MethodologyPhases
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Experimental ProcedureDetermining optimal ratio
of keratin to elastin

• Spin the optimal parameters of Keratin and
  Elastin.
• Measure Tensile strength of optimal hybrid mat
• Repeat the experiment with different flow rate of
  Keratin and Elastin respectively.

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Results AnalysisPhase 2

• Plot a graph of amount of Beading against
  Independent Variable Tested
• The lesser number of beading, the better the
  fibers
• Plot a graph of diameter of the nanofibers
  against Independent Variable Tested.
• A consistent diameter of the fiber is considered
  the best

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Results AnalysisPhase 3

• Plot a graph of tensile strength against flow
  rate of different ratios. (one of which is the
  optimal spinning condition)

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Results Analysis

• 1. We will be measuring the tensile strength and
  extensibility of each of the fibrous mats.
  Multiple small sections of each mat spun will be
  tested for both extensibility and tensile
  strength.  This allows for multiple data points
  for each set of variables without using as much
  of the materials.
•  
• 2. We will be comparing the extensibility and
  tensile strength of each set of mats to that of
  spider silk, trying to find the parameters that
  best mimic the properties of this material.  

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Results Analysis

• 4. Analysis of variance (ANOVA) tests will be run
  on each variable. There will be three trials run
  for each variable at very spread out points. Each
  of those mats will be tested for extensibility
  and tensile strength, using 5 small sections of
  each mat if possible to achieve more data points.
  These data points will be graphed on the same
  graph as variable x vs. elasticity and
  variable x vs. tensile strength, variable x
  being the variable currently being tested. The
  area on this graph where the tensile strength and
  extensibility are determined to be optimal in
  ratio will be tested in smaller increments to
  determine a more exact value for optimal
  condition of variable x. This will be repeated
  for all the variables.
•  
• 5. The data points from each mat will be averaged
  together for each of the data points. There will
  be about five segments taken from each mat. There
  will be three spread out conditions tried for
  each variable, and five tested once a more
  specific region is tested.
•  
•  

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Results Analysis

• 6. ANOVA tests will be run initially on each
  variable. Data points will then be combined into
  scatter plots with two dependent
  variables(elasticity and tensile strength) and
  one independent variable, like distance to the
  collector plate.
•  
•  

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Timeline
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Bibliography

• Aluiji, A., Ferrero, F., Mazzuchetti, G., Tonin,
  C., Varesano, A., Vineis, C.(2008) Structure and
  properties of keratin/PEO blend nanofibers.
  European Polymer Journal. 44. 2465-2475.
•  
• Awazu, K., Ishii, K., Kanai, T., Natio, Y.,
  Yashihashi-Suzuki(2004). Matrix-assisted laser
• desorption/ionization of protein samples
  containing a denaturant at high concnetratin
  using a mid-infrared free electron laster
  (MIR-FEL). International Journal of Mass
  Spectrometry. 15. 49-46.
•  
• Buttafoco, L., Dijkstra, P.J., Engbers-Buijtenhuij
  s, P., Feijen, J., Kolkman, N.G., Poot, A.A.,
• Vermes, I.(2006). Electrospinning of collage and
  elastin for tissue engineering applications.
  Biomaterials. 27. 224-234
• MSDS Sheets
• Keratin Powder http//www.sciencelab.com/msds.php
  ?msdsId9924435
•  
• Elastin from bovine neck ligament
  http//www.sigmaaldrich.com/catalog/ProductDetail.
  do?langenN4E1625SIGMAN5SEARCH_CONCAT_PNOBRA
  ND_KEYFSPECtest, click MSDS on left side bar
•  
• 1 M hydrochloric acid http//www.jtbaker.com/msds
  /englishhtml/H3880.htm
•  
• Polyethylene oxide(PEO) http//www.sigmaaldrich.c
  om/catalog/Lookup.do?N5AllN3modematchpartialma
  xN4polyethyleneoxideD70D10polyethyleneoxide
  N1S_IDSTRSN250FPRtest, click MSDS on left
  side bar

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Q A
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The End

• Thank you!