Nanofabrication of protein-patterned substrates for future cell adhesion experiments

A method for fabricating sub-micrometer size adhesion sites for future experiments in cell biology is presented. Glass substrates were coated with a thin layer of InSnO and SiO"2. The SiO"2 was structured by means of electron beam lithography and reactive ion etching, exposing sub-micrometer patches of the underlying InSnO. Dodecylphosphate, to which proteins can bind, was selectively adsorbed on these InSnO structures, whereas poly-l-lysine-g-poly(ethylene glycol) was used to passivate the surrounding SiO"2 against protein adsorption. The effectiveness of the process was investigated by fluorescent microscopy and scanning near-field optical microscopy on substrates which have been exposed to fluorescently labeled streptavidin.