Generic, S N 2 reactive silicone surfaces protected by poly(ethylene glycol) linkers: facile routes to new materials

The efficacy of biomaterials is frequently dependent upon the interface between a synthetic material and the surrounding biology. While silicones offer many benefits in biomaterials applications, they can suffer from insufficient hydrophilicity. We present a controlled and generic route to the surface modification of silicones that permits the introduction of a passivating poly(ethylene glycol) (PEG) layer capped with biologically relevant molecules. High-density, tosylate-modified, PEG-tethered silicone surfaces are readily prepared. These surfaces provide a generic platform for further surface modification by nucleophilic substitution (SN2). The efficiency of substitution at the surfaces was established using a broad variety of nucleophiles: although triphenylphosphine did not modify the tosylated surface, the surface reaction of primary amines, azide, and a thiol was demonstrated to be highly efficient in organic solvents at several temperatures. Changes in surface chemistry and properties were demonstrated by water contact angle, ATR-FTIR, XPS and 13C solid-state NMR spectroscopy.