Functionalization of Surfaces with Nisin in a Polyethylene oxide brush layer

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Functionalization of Surfaces with Nisin in a
Polyethylene oxide brush layer

• Matt Ryder
• Dr. Joe McGuire BioEngineering
• OSU
• HHMI Summer 07

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Background Instances of Infection1

• Infection in hospitals is the fourth largest
  killer in the US
• 2 million patients contract infections in
  hospitals each yearabout 103,000 die as a result

• 228 infections/hour12 deaths
• Cost? 30.5 billion each year

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Background

• Three issues with implanted devices
• Clot Formation
• Bacterial Adhesion
• Cell Proliferation

• Currently, methods to counteract include
• Loading patients with heparin or antibiotics.

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Background

• These issues are directly related, both are
  initiated by adsorption events.

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Background Brush Layer

• F108 creates brush layer that protects against
  protein adsorption.
• Protein adsorption can result in very different
  outcomes, from benign surface coatings, to large
  clot formation (therefore risk of stroke).

Hydrophobic Surface
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Brush Layer Protein Repellant
A.
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Background Nisin
Nisin is a small antimicrobial peptide produced
by strains of Lactococcus lactis subsp. lactis.
Nisin kills Gram positive bacteria through a
multistep process that destabilizes the
phospholipid bilayer of the cell and creates
transient pores. The efflux of low molecular
weight compounds from the cytoplasm and
subsequent dissipation of membrane potential
rapidly kills the targeted bacterium.
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Nisin - Mechanism
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Background Nisin Brush Layer

• Goes against function of brush layer

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Background Product Activity
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Hypothesis

• If a surface can be chemically or functionally
  modified to adsorb and retain the Lantibiotic
  Nisin, antimicrobial activity and anti clotting
  function will be higher as compared to current
  coating methods.

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Procedure
microspheres
F108
Nisin
Pediococcus
2 days
overnight
x of days
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Results

• Optimized concentrations of F108, Nisin and
  microspheres in solution.
• Conducted serial dilution tests to find optimum
  concentration of Pediococcus.
• Researched literature for background knowledge
  and future effectiveness
• Standardized procedures to decrease variability.
• Obtained valuable insight on Nisin activity from
  longevity testing.

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Results
10-6 dilution w/o Nisin 10-4 dilution w/
Nisin Dilution optimized for 30-300 colonies
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Results
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Results
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Future Research

• 28 day trials with current procedure
• Blood serum studies to test longevity of Nisin in
  physiological conditions
• Tests with EGAP rather than F108, a more
  clinically accepted polymer
• in vitro studies using catheters

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Acknowledgements

• Special Thanks to
• Dr. Joe McGuire Mentor
• Dr. Christine Kelly
• Karle Schilke
• Dr. Jeff Tai Protocols and instruction
• Dr. Kevin Ahern HHMI Program
• The Howard Hughes Medical Institute

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References

• 1. Committee to Reduce Infectious Diseases
  http//www.hospitalinfection.org/essentialfact
  s.shtml
• Pictures
• 1. http//www.flickr.com/photos/gaspirtz/38425422
  5/
• 2. www.altham.com/html/food_hygiene_cartoons.html
  
• 3. http//www.sciencestuff.com/prod/L-p-Empty/100
  1-20
• 4. http//www.flickr.com/photos/rdbkorn/85401201/
  
• 5. http//www.bergoiata.org/fe/favs/Bacteria.jpg
• 6. www.sigmaaldrich.com/img/assets/4261/micro_7.
  gif