AVS 53rd International Symposium
    Biomaterial Interfaces Wednesday Sessions
       Session BI-WeA

Paper BI-WeA9
Investigating the Protein Repellent Properties of Highly Crosslinked Oligo Ethylene Glycol-Like Plasma Polymer Films through Surface Force Measurements with Colloidal Probe Atomic Force Microscopy.

Wednesday, November 15, 2006, 4:40 pm, Room 2014

Session: Bio-Interfacial Modification and Bio-Immobilization II (Honoring Marcus Textor, ETH-Zürich for Substantial Contributions to the Field)
Presenter: B.W. Muir, CSIRO, Australia
Authors: B.W. Muir, CSIRO, Australia
A. Tarasova, CSIRO, Australia
T.R. Gengenbach, CSIRO, Australia
L. Meagher, CSIRO, Australia
F. Rovere, CSIRO, Australia
K. McLean, CSIRO, Australia
A. Fairbrother, CSIRO, Australia
P.G. Hartley, CSIRO, Australia
Correspondent: Click to Email
Interaction forces of highly protein resistant polyethylene glycol (PEG)-like plasma polymer films were investigated with colloid probe atomic force microscopy (AFM). The technique of radio frequency glow discharge plasma polymerisation was used to deposit protein resistant films from diethyleneglycol dimethylether (DG) on a heptylamine (HA) plasma polymer (pp) layer. Films were characterised using a combination of techniques including X-ray Photoelectron Spectroscopy, Electrokinetic Streaming Potential Measurements, Secondary Ion Mass Spectroscopy and AFM. The interaction force measurements of a bare silica probe with the plasma polymer films are discussed in relation to observed bovine serum albumin fouling in phosphate buffered saline. A DGpp film was produced with a high ether content which resulted in sub 10 ng/cm@super 2@ levels of protein on these films. We have found that a compressible DGpp with a steric repulsive interaction on the order of only 3 nm provides a non-fouling PEG-like surface. The steric behaviour of the protein resistant and fouling DGpp films was equivalent in high ionic strength solution with differences due to van der Waals and electrostatic attractions detected in low ionic strength solution. We have shown that thin DG films retain their protein repellent properties regardless of the net surface charge and potential. We therefore deduce that surface free energy and potential is not a key determinant in the protein resistance of inert DGpp surfaces nor is the hydrophilicity and roughness of the films. We believe that it is the density of the residual ether functionality and a short range steric repulsive interaction in these films which is the key factor determining their protein resistance and not long range electrostatic or steric interactions. These experiments further highlight the utility of aqueous surface force measurements toward understanding the protein repellent properties of highly crosslinked PEG-like pp films.