Multiple and terminal grafting of linear polyglycidol for surfaces of reduced protein adsorption

Abstract

Hydrophilic surfaces based on linear polyglycidol (poly(2,3-epoxypropanol-1)) were prepared to examine protein-surface interactions. The grafting-to technique was applied to covalently attach the polyglycidol and its block copolymer with poly(ethylene glycol) to the silica wafers. Two types of surfaces with different polymer chains binding to the substrate were prepared and its ability to reduce the protein adsorption was compared. In the first case, a reaction between the hydroxyl groups of the linear polyglycidol (of Mn 8000 g/mol or 1.9x106 g/mol) and the anhydride groups of the surface was applied, causing multiple attachment of the polymer chain to the surface. In the second case, the living polyglycidol (Mn 8000 g/mol) or poly(glycidol-co-ethylene glycol) (Mn 6000 g/mol) chains were terminated by the chloropropyl groups of the surface leading to polymer brushes. Hydrophilic surfaces with polymer layer thickness between 1.5 and 140 nm were obtained. The morphology, affinity to water and layer thickness were influenced by the molar mass of the immobilized (co)polyglycidol and the type of binding with the surface. It was established that the fibrinogen adsorption was limited to 45–90% on the polyglycidol-coated surfaces compared to the bare silicon wafers. The ability to reduce fibrinogen adsorption was dependent on the molar mass of the polymer, polymer layer thickness, type of polymer bonding with the surface and presence of poly(ethylene glycol) on the outer surface layer.