Functionalization of Surfaces with Nisin in a PEO-PPO-PEO brush by pengxuebo

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									 Functionalization of Surfaces with Nisin
 in a Poly[ethylene oxide] brush layer

Matt Ryder
Dr. Joe McGuire – BioEngineering
OSU
HHMI Summer ‘07



                        Hydrophobic Surface
        Background – Instances of Infection1
   Infection in hospitals is the fourth largest
    killer in the US
   2 million patients contract infections in
    hospitals each year…about 103,000 die as
    a result
       228 infections/hour…12 deaths
   Cost? $30.5 billion each year
Background
   Three issues with implanted devices
     Clot Formation
     Bacterial Adhesion
     Cell Proliferation
   Currently, methods
    to counteract
    include:
       Loading patients
        with heparin or
        antibiotics.
Background
   These issues are directly related,
    both are initiated by adsorption
    events.
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
Brush Layer – Protein Repellant



  Bare Surface      F108 Coated Surface




  Bare Surface      F108 Coated Surface

      A.                    B.
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.
Nisin - Mechanism
  Background – Nisin & Brush Layer

     Goes against function of brush layer




Hydrophobic Surface         Hydrophobic Surface
Background – Product Activity




           Hydrophobic Surface
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.
Procedure
         microspheres



              F108


               Nisin
                                          c us
                                      oc
                                   oc            2 days
                               e di
                              P

ov
  er
    ni
       gh
          t
                       x # of days
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.
Results

          10-6 dilution w/o Nisin

          10-4 dilution w/ Nisin

          Dilution optimized for
             30-300 colonies
Results
Results
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
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
   References
  1. Committee to Reduce Infectious
     Diseases
     http://www.hospitalinfection.org/essentialfacts.shtml

Pictures
  1. http://www.flickr.com/photos/gaspirtz/384254225/
  2. www.altham.com/html/food_hygiene_cartoons.html
  3. http://www.sciencestuff.com/prod/L-p-Empty/1001-20
  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

								
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