title: One step growth of protein antifouling surfaces: monolayers of poly(ethylene oxide) (PEO) derivatives on oxidized and hydrogen-passivated silicon surfaces.
abstract: We compare two routes for creating protein adsorption-resistant self-assembled monolayers (SAMs) by chemical modification of silicon surfaces with poly(ethylene oxide) (PEO) oligomeric derivatives. The first route involves the assembly of 2-methyl[(polyethyleneoxy)propyl]trichlorosilane (Cl3SiMPEO) films onto oxidized silicon surfaces (OH-SiO(x)) either by a liquid-phase process at room temperature or by a gas-phase process at 423 K, producing Si-O-Si bonds between the substrate and the organic layer. The second pathway makes use of the assembly of poly(ethylene glycol methyl ether) (MPEG) films onto hydrogen-passivated silicon surfaces (H-Si) using a liquid-phase process at 353 or 423 K, leading to the formation of Si-O-C bonds between the substrate and the organic layer. Structural investigation by X-ray reflectometry (XRR) reveals that the thickness and surface densities of the grafted PEO monolayers strongly depend on experimental conditions such as temperature and grafting time. Atomic force microscopy (AFM) shows that very smooth and homogeneous monolayers can be obtained with average roughnesses close to those measured on the corresponding bare substrates. Finally, the antifouling properties of the modified silicon surfaces were evaluated by X-ray photoelectron spectroscopy (XPS), using a membrane protein (P.69 antigen) as model protein. Both types of PEO monolayers exhibit excellent protein repellency, as soon as the grafting density is equal to or higher than 1.7 chains/nm2.
authors.affiliation: Unité de chimie et de physique des hauts polymères (POLY) and Research Center on Micro- and Nanoscopic Materials and Electronic Devices, Université Catholique de Louvain, Croix du Sud 1, B-1348 Louvain-la-Neuve, Belgium (EU).
authors.forename: Francesca
authors.initials: F
authors.lastname: Cecchet
authors.forename: Benoît
authors.initials: B
authors.lastname: De Meersman
authors.forename: Sophie
authors.initials: S
authors.lastname: Demoustier-Champagne
authors.forename: Bernard
authors.initials: B
authors.lastname: Nysten
authors.forename: Alain M
authors.initials: AM
authors.lastname: Jonas
mesh_terms: D006859:Hydrogen / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D010084:Oxidation-Reduction; D011092:Polyethylene Glycols / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry*; D013057:Spectrum Analysis / Q000379:methods; D013499:Surface Properties
chemical_list: D011506:Proteins; D011092:Polyethylene Glycols; D006859:Hydrogen; D012825:Silicon