Bioinformatics-Trends and Methodologies 610 analysis of multiple cell types or stimuli. Experiments with multiwell plates are typically integrated in a robotic analysis platform. Two major drawbacks of robotic platforms are the expense of the instrumentation, and the cost of experimental consumables. The use of microarrays was first reported in 1989 (Ekins et al., 1989). The variety and diversity of microarrays has become impressive. Three main types of microarrays have been developed: DNA microarrays, protein microarrays, and cell microarrays (Barbulovic-Nad et al., 2006). Several different approaches to cell microarrays have been explored to investigate gene expression, cell-surface interactions, extracellular matrix composition, cell migration and proliferation, the effects of drugs on cellular activity and many other areas (Angres, 2005). There are two fundamental methods to produce cell microarrays: the indirect and the direct method. The indirect method-i.e. the "reverse transfection" method-was developed by Ziauddin and Sabbatini (2001). In the direct method, the cells are printed onto a substrate. In few cases contact-based microarrayers are used, but more often non-contactbased devices are used. Miniaturisation of cellular assays via cell microarrays increases assay throughput while reducing reagent consumption and the number of cells required, making these systems attractive for a wide range of assays in drug discovery, toxicology, and stem cell research (Fernandes et al., 2009). Cell microarrays have been developed for highly parallel, highthroughput analyses of cell phenotypes (