Protein-resistant polymer coatings on silicon oxide by surface-initiated atom transfer radical polymerization

The modification of silicon oxide with poly(ethylene glycol) to effectively eliminate protein adsorption has proven to be technically challenging. In this paper, we demonstrate that surface-initiated atom transfer radical polymerization (SI-ATRP) of oligo(ethylene glycol) methyl methacrylate (OEGMA) successfully produces polymer coatings on silicon oxide that have excellent protein resistance in a biological milieu. The level of serum adsorption on these coatings is below the detection limit of ellipsometry. We also demonstrate a new soft lithography method via which SI-ATRP is integrated with microcontact printing to create micropatterns of poly(OEGMA) on glass that can spatially direct the adsorption of proteins on the bare regions of the substrate. This ensemble of methods will be useful in screening biological interactions where nonspecific binding must be suppressed to discern low probability binding events from a complex mixture and to pattern anchorage-dependent cells on glass and silicon oxide.