A flexible multiwell format for immunofluorescence screening microscopy of small-molecule inhibitors

Large-scale screens in mammalian cells demand for flexible high-throughput screening platforms that allow to analyze cellular traits on a genome-wide level or to identify small-molecule inhibitors (SMIs) from complex compound libraries. In this study we developed and tested high-density cell arrays made out of polydimethylsiloxane (PDMS) that support cell growth directly on standard glass microscope objective slides. We analyzed the effect of 3 reference inhibitors (MLN-8054, VX-680, and flavopiridol) and 4 exploratory, cell permeable small-molecule kinase inhibitors (two benzothiophene-based and two 4-amino-6-arylpyrimidine-based compounds) on different cell lines, using prototype 5 × 5 and 9 × 9 array carpets. We found that high-density PDMS cell arrays support growth of a broad range of cell types, are well suited for compound screens, and are compatible with high-content screening platforms. This novel array format is of particular advantage for compound screening to identify SMIs, when a combination of flexibility with respect to culture volume, well density, and high-resolution imaging is required. In addition, we demonstrated the suitability of this format for reverse transfection and siRNA experiments.