Microscopic arrays of biosensors can be formed by patterning chemically or biochemically functional groups onto surfaces, e.g., by photolithography or microprinting. A method of fabrication of microscopic biosensor arrays is described that has the advantage, compared to the above mentioned methods, of not requiring microscopic alignment: first, self-assembled monolayers (SAMs) are spatially selectively removed from gold arrays by electrochemical desorption, then the exposed elements are remodified with SAMs formed of different alkanethiolates.