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

Paper BI-WeA7
Control of Protein Adsorption Using Poly(propylene sulfide)-block- poly(ethylene glycol) Adlayers: New Potential Candidate for the Modification of Biosensor Chip Surfaces

Wednesday, November 17, 2004, 4:00 pm, Room 210D

Session: "Passive" and Non-Fouling Surfaces
Presenter: L. Feller, Swiss Federal Institute of Technology (ETHZ), Switzerland
Authors: L. Feller, Swiss Federal Institute of Technology (ETHZ), Switzerland
S. Tosatti, Swiss Federal Institute of Technology (ETHZ), Switzerland
S. Cerritelli, Swiss Federal Institute of Technology (EPFL), Switzerland
S. Terrettaz, Swiss Federal Institute of Technology (EPFL), Switzerland
M. Textor, Swiss Federal Institute of Technology (ETHZ), Switzerland
J.A. Hubbell, Swiss Federal Institute of Technology (EPFL), Switzerland
Correspondent: Click to Email
Poly(ethylene glycol) (PEG) has been used in numerous biomedically relevant systems to aid in the minimization of protein adsorption and cell adhesion. PEG can be attached to surfaces through a variety of different approaches including silanization, self-assembly of thiols, and plasma polymerization. In our approach a block copolymer containing one (di- block) or two (tri-block) PEG chains separated by a poly(propylene sulfide) (PPS) part was used. Adsorbed to gold surfaces, a stable linkage between the sulfur atoms of the PPS thioether and the metal surface was observed. The hydrophilic PEG part formed a dense layer of biocompatible PEG chains, which is exposed to the aqueous environment. Various architectures of di- and tri-block PPS-PEG copolymers were synthesized, characterized, and deposited on gold substrates. While the PPS part was kept constant (MW 4000), the PEG part was varied between 1100 and 5000 Da molecular weight. Adsorption of the polymer to the gold surface was characterized by ex situ ellipsometry, X-ray photoelectron spectroscopy (XPS), and in situ surface plasmon resonance (SPR). The resistance of the surfaces to protein adsorption was evaluated using SPR. PPS-PEG readily chemisorbed on gold surfaces after a simple dip-and-rinse process in 1mg/ml methanol solution. We compared different architectures of PPS-PEG and correlated the PEG/PPS ratio with adsorbed mass values and resistance to protein (HSA) adsorption with the aim to find the optimum architecture regarding surface adhesion, stability, polymer conformation and protein resistance.