PEG Hydrogel Coating for Medical Devices B. Mulawka, B. Roedl, P. Schenk, D. Patel Advisor: Professor William Murphy, Client: Arthur J. Coury Ph.D, Vice President of Biomaterials Research, Genzyme Corporation

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PEG Hydrogel Coating for Medical DevicesB.
Mulawka, B. Roedl, P. Schenk, D. Patel Advisor
Professor William Murphy, Client Arthur J. Coury
Ph.D, Vice President of Biomaterials Research,
Genzyme Corporation
Problem Statement
Results
Procedure
Form a microlayer of PEG based hydrogel onto
material surfaces in order to examine and improve
upon their characteristics and biocompatibility.

• Stain specimen in 50ppm Eosin Y
  solution from two hours to one week
• Rinse with distilled water heavy, light, no
  rinse, bath
• Immerse specimen in macromer (PEG) solution and
  apply light from source for 40s
• Soak in saline to equilibrate any gel formed on
  surface
• View specimen under microscope to measure
  thickness by comparison to 6 micron polystyrene
  beads
• Used subjective test to measure adherence

Motivation
Our ultimate goal is to coat a urinary catheter
with a uniform biocompatible hydrogel with
sufficient material adhesion which we believe
will improve upon the problems associated with
existing long-term catheters.

• All surfaces showed poor hydrogel adhesion
• Eosin did not adhere to surface
• All thicknesses were under 40 microns
• Client specifies 25-100 microns
• Non-uniform surface coatings
• Increased time in eosin Y solution did not affect
  hydrogel adhesion
• Increased rinsing of material before
  photopolymerization caused a decrease in hydrogel
  thickness but did not affect hydrogel adhesion

Client Specifications

• Create a detailed process for applying a hydrogel
  to surfaces
• Testing of thickness and adherence of hydrogel
  coatings
• Testing of fouling resistance of hydrogels in
  physiologically imitated environments
• bovine albumin solution, pH 7.35

Future Work
Materials

• Modify Staining Procedure
• Increase concentration of Eosin Y
• Change to Ethyl Eosin stain (more hydrophobic)
• Allow material to dry after Ethyl Eosin is
  applied
• Increase light application time during
  photopolymerization
• Focus on coating of latex and PVC
• Continue to test adhesion of hydrogel to
  substrate surface
• Test biocompatibility by exposing hydrogel coated
  material to bovine albumin solution

• PEG Nontoxic polymer. In water, helical
  structure, viscous, neutral, repulsive of charged
  molecules. Minimizes protein and cell interaction
  and decreases host response.
• Uses drug delivery matrix, biomaterial
  synthesis, food additives, wound dressings, soft
  tissue replacement
• PVC Hydrophobic surface. Used as tubing for
  blood transfusion, dialysis, and feeding.
  Biologically inert, can be used as a negative
  control
• Polystyrene Hydrophobic surface. Polar groups
  can be introduced to give the surface ionic or
  dipole-dipole bonding properties. Used to make
  Petri dishes and cell culture wells, good
  material for testing cell adhesion.
• Glass Hydrophilic and negatively charged
  surface. Used for eyeglasses, chemical ware,
  thermometers, tissue culture flasks, and optics
  in endoscopy.

Urinary Catheters

• Made of latex, PVC, silicon, PTFE (Teflon)
• Chance of failure 100 within weeks to months
• Catheter obstruction due to crystallization of
  proteins and bacteria collection
• Dependent upon patient and coating
• Silver nitrate, antibiotics, Norfloxacin
• Difficult to coat due to curvature of surface

References

• Kenneth Messier, Genzyme Corp.
• McNair, Andrew M. "Using Hydrogel Polymers for
  Drug Delivery." Medical Device Technology (1996).
  
• Kizilel, Seda, Victor H. Perez-Luna, and Fouad
  Teymour. "Photopolymerization of Poly(Ethylene
  Glycol) Diacrylate on Eosin-Functionalized
  Surfaces." Langmuir (2004).
• Levillian, Pierre, Dominique Fompeyide.
  Demonstration of Equilibrium Constants by
  Derivative Spectrophotometry. Aplication to the
  pKas of Eosin. Anal. Chem. (1988).
• Cruise, Gregory. Scharp, David. Hubbell, Jeffrey.
  Characterization of permeability and network
  structure of interfacially photopolymerized
  poly(ethylene glycol) diacrylate hydrogels.
  Biomaterials. (1998)