AVS 51st International Symposium
    Biomaterial Interfaces Wednesday Sessions
       Session BI-WeA

Paper BI-WeA2
The Effect of Cloud-Point Grafting of Sulfonated Poly(ethylene glycol) on Albumin Adsorption

Wednesday, November 17, 2004, 2:20 pm, Room 210D

Session: "Passive" and Non-Fouling Surfaces
Presenter: L.G. Britcher, University of South Australia
Authors: L.G. Britcher, University of South Australia
H.J. Griesser, University of South Australia
Y.H. Kim, Korea Institute of Science and Technology
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Sulfonated poly(ethylene glycol) (PEG-SO@sub 3@) has shown promise as a thromboresistant material, although its activity does reduce when grafted onto a polyurethane surface. It is thought that a synergistic effect exists between the PEG and terminal SO3 groups, improving its blood compatibility@footnote 1@. The flexible hydrophilic PEG chains cause protein rejection by a steric barrier mechanism, while the negative charge of the SO@sub 3@ terminal groups causes electrical repulsion of negatively charged proteins and platelets@footnote 1@ @super ,@@footnote 2@. Though platelet adhesion is decreased on PEG-SO@sub 3@ grafted surfaces compared with PEG grafted surfaces, protein adsorption is not suppressed completely. A negative cilia adsorption model has been proposed for these surfaces, however, it does not explain why albumin adsorption is enhanced. Therefore, further work is required in order to understand what conformation of the PEG-SO@sub 3@ on the surface along with the distribution of SO@sub 3@ groups will lead to improved anti-fouling properties. One method for changing the PEG conformation is to use cloud point conditions for grafting the PEG. Surfaces grafted under these conditions have shown to decrease protein adsorption significantly, as the coating is very dense due to the brush conformation of the PEG@footnote 3@. However, charge repulsion effects may arise with densely packed sulfonated PEGs. In this study, we aim to investigate whether cloud point conditions can be used to graft PEG-SO@sub 3@ onto surfaces and if the coating thus obtained suppresses albumin adsorption. This should lead to further understanding of the protein adsorption model on PEG-SO@sub 3@ surfaces. @FootnoteText@ @footnote 1@ Y. Hann et al., Biomaterials 24, 2213 (2003).@footnote 2@ H. Lee et al., Colloid Surf B: Biointerfaces 18, 355 (2000).@footnote 3@ P Kingshott et al., Biomaterials 23, 2043, (2002).