A novel approach to the micropatterning of proteins using dewetting of polymer bilayers.

The ability to control protein and cell positioning on a microscopic scale is crucial in many biomedical and bioengineering applications, such as tissue engineering and the development of biosensors. We propose here a novel, simple, and versatile method for the micropatterning of proteins. Micropatterned substrates are produced by the dewetting of a metastable polymer film on top of another polymer film. Selective adsorption, or micropatterning, of proteins can be achieved on such substrates by choosing pairs of polymers which differ in protein affinity. In this study, patterns were produced in bilayers of poly(methylmethacrylate) (PMMA) and polystyrene (PS), and of PMMA and octadecyltrichlorosilane (OTS). Fluorescence microscopy and atomic force microscopy (AFM) provide evidence that model proteins adsorb preferentially on isolated bio-adhesive (PS and OTS) micropatches in a protein-resistant (PMMA) matrix. "Inverse" protein patterns, containing non-adhesive (PMMA) islands in a protein-adhesive (PS) matrix can also be produced. Such micropatterned substrates could potentially be used in the development of biosensors and bioassays, and in the study of cell growth and motility.