Sensors based on surface plasmon resonance have demonstrated, over the last 2 decades, to be an effective method of studying biomolecular interactions without the need for labeling. Recently, it has been adapted to high-throughput use for imaging microarray binding in real time. This provides a promising platform - a label-free protein microarray system - for the study of disease. In this example, antibody microarrays are used to efficiently profile the secretion of proteins from a cell line exposed to varying concentrations of a toxic compound.