Abstract: Described is a method for electrochemically patterning a microelectrode array (MEA) with at least two different kinds of macromolecules. Said method comprising the steps of: providing a platform with a surface that comprises individually addressable conductive microelectrode surfaces; covering said platform surface with an adlayer of resistant polymer; desorbing said adlayer from a first kind of conductive microelectrodes intended for the selective adsorption of a first kind of macromolecules, in particular proteins, by applying a potential; subjecting the desorbed surfaces to the first macromolecule under conditions such that said first macromolecule adsorbs to said desorbed surfaces, and repeating the desorption/adsorption steps with a second or further kind of macromolecules until all kinds of desired macromolecules are adsorbed. A microchip array produced by the inventive method is also described. Such chip arrays can be used to study a large diversity of biological interactions, e.g.