Membrane-based assays using surface detector array devices suitable for use with a biosensor are disclosed. The device is formed of a substrate having a surface defining a plurality of distinct bilayer-compatible surface regions separated by one or more bilayer barrier regions. The bilayer-compatible surface regions carry on them, separated by an aqueous film, supported fluid bilayers. The bilayers may contain selected receptors or biomolecules. A bulk aqueous phase covers the bilayers on the substrate surface. Arrays may be engineered to display natural membrane materials in a native fluid bilayer configuration, permitting high-throughput discovery of drugs that target and affect membrane components. The membrane-based assays detect binding events by monitoring binding-induced changes in one or more physical properties of fluid bilayers.