In application areas such as crop genotyping, plant diagnostics, pharmaceuticals and forensics, screening a large number of M samples for specific responses to a library of N active agents in a time- and cost-efficient manner is of critical importance. Parameters of interest include response of cells to a specific drug compound, identification of specific genes or plant pathogens in crops using DNA markers and DNA traceability for food safety. The cost of reagents as well as the liquid handling ro-botics required to perform the enormous number of pipetting steps severely hamper the proliferation of such key technologies into smaller laboratories.