Immobilization of a functionalized poly(ethylene glycol) onto [beta]- cyclodextrin-coated surfaces by formation of inclusion complexes: Application to the coupling of proteins

• Published in: Journal of applied polymer science 2006-01, Vol.100 (3), p.2362-2370
• Main Authors: Guerrouache, M, Karakasyan, C, Gaillet, C, Canva, M, Millot, M C
• Format: Article
• Language: English
• ISSN: 0021-8995
• DOI: 10.1002/app.23082

The aim of this study was the immobilization of COOH-modified poly(ethylene glycol) (PEG) layers onto [beta]-cyclodextrin-coated surfaces by formation of inclusion complexes, in view of biosensors applications. To this end, PEGs with one phenyladamantyl and one carboxylic end group (Ad-PEG-COOH) were prepared according to a three-step procedure. After modification of PEG with 4- toluenesulfonylchloride, the reaction of the tosyl intermediate with the alcoholate of 4-(1-adamantyl)-phenol was carried out in tetrahydrofuran to avoid the formation of by-products. Then, it was shown by high performance liquid chromatography that the association between [beta]-cyclodextrin cavities and Ad- PEG-COOH polymers was not hindered by the presence of the COOH group. Last, the Ad-PEG-COOH polymer was immobilized onto [beta]-cyclodextrin-coated gold surfaces by formation of inclusion complexes. The immobilization was performed in water, at room temperature, with a rapid kinetics. After activation of COOH groups with N-hydroxysuccinimide, [beta]-lactoglobulin was coupled to the biocompatible PEG layer. Functionalization of the gold surface with [beta]- cyclodextrin cavities, immobilization of Ad-PEG-COOH onto the surface, and coupling of the protein to the reactive PEG layer were followed in real time by surface plasmon resonance imaging system.