AVS 52nd International Symposium
    Plasma Science and Technology Tuesday Sessions
       Session PS+BI-TuM

Paper PS+BI-TuM2
A Novel, Single-Step Method for the Preparation of Chemical Gradient Surfaces Using Non-Uniform Plasma-Deposition

Tuesday, November 1, 2005, 8:40 am, Room 302

Session: Plasmas in Bioscience
Presenter: T.R. Gengenbach, CSIRO Molecular Science, Australia
Authors: T.R. Gengenbach, CSIRO Molecular Science, Australia
P.G. Hartley, CSIRO Molecular Science, Australia
H. Thissen, CSIRO Molecular Science, Australia
K.M. McLean, CSIRO Molecular Science, Australia
L. Meagher, CSIRO Molecular Science, Australia
G. Johnson, CSIRO Molecular Science, Australia
Correspondent: Click to Email
Gradient surfaces are characterised by a gradual and systematic variation of one or more chemical and physical properties along a specific direction. They are of increasing importance in combinatorial chemistry and materials science where they are being used to generate libraries of widely varying surface properties to study interfacial phenomena. In biomaterials research gradient surfaces can be employed to rapidly explore multi-variable parameter space, either to investigate how relevant variables (e.g. surface chemistry, wettability, charge) affect biocompatibility, or alternatively, to accelerate the optimisation of coupling strategies for covalent attachment of secondary layers. Radio frequency glow discharge plasma polymer coatings form robust thin films which contour and adhere strongly to the surfaces of polymeric and other materials. Their ability to modify surface properties, either by enhancing biocompatibility, or by introducing defined chemical functionalities at interfaces for the subsequent coupling of bioactive molecules, have seen their widespread application in the field of biomaterials research. We have developed a novel method to deposit plasma polymer coatings with systematically varying properties along the surface. In a standard plasma reactor with capacitively coupled electrodes the substrate to be coated is placed on a large flat horizontal base electrode (earthed); the second, specially shaped top electrode (active) is lowered to within millimetres of the substrate surface. The resulting plasma discharge is spatially non-uniform and produces surfaces with a strong gradient of chemical/physical properties. By controlling the shape of the top electrode we have also prepared patterned surfaces with well defined regions of widely different properties (e.g. density of specific functional groups). These gradient surfaces have been evaluated with respect to the biological response, such as protein adsorption and cell attachment.