Reactive polymer coatings: A platform for patterning proteins and mammalian cells onto a broad range of materials

We report a procedure for surface modification based an chemical vapor deposition polymerization of functionalized [2.2] paracyclophanes that is essentially substrate-independent. Poly(p-xylylene-2,,3-dicarboxylic anhydride) and poly[p-xylylene carboxylic acid pentafluorophenolester-co-p-xylylene] are examined as templates for cell patterning. Both reactive coatings are deposited on poly(tetrafluoroethylene), polyethylene, silicon, gold, stainless steel, and glass and show excellent adhesion when deposited in thin films (ca. 100 nm) under optimized polymerization conditions. X-ray photoelectron spectroscopy and grazing angle infrared spectroscopy have been used to confirm chemical homogeneity in both cases. Reactive coatings are subsequently patterned by microcontact printing of an amino-terminated biotin ligand and serve as templates for layer-by-layer self-assembly. Streptavidin selectively binds to the biotin-exposing surface regions and allows surface confinement of a biotin-tethered antibody against alpha5-integrin. The specific interaction of this antibody with endothelial cells results in spatially directed deposition of mammalian cells. Fluorescence microscopy is used to verify accurate self-assembly at each step. Although both reactive coatings differ in how they chemically bind biomolecules, their ability to support formation of pattern by microcontact printing is similar.