Microsystems for the analysis of cellular signal transduction

Drug development and cell biological research alike are confronted by the complexity of molecular signal transduction networks. These networks integrate information from different stimuli inside the cell. Progress in both disciplines will largely depend on experimental techniques that reflect the complexity of cellular signalling networks. The testing of combinations, either of drug candidates or of stimuli is considered one promising solution of this challenge. However, the systematic testing of combinations introduces a new dimension of experimental complexity. Miniaturization, parallelization and especially a reduction of the number of steps required for the preparation of samples are prerequisites for resolving this dilemma. As a solution for the testing of different combinations of drug candidates, we present the generation of substance mixtures by diffusion. For each combination of compounds only two pipetting steps are required for generating a virtually unlimited number of different test conditions. The potential of testing the response of cells to systematic combinations of different stimuli is demonstrated by using antibody microarrays where each spot carries a different combination of stimulatory antibodies. Both experimental strategies are combinatorial in nature. Through miniaturization and implementation of high-content read-outs a maximum of information is obtained with a minimum of manipulations.