Embryonic stem (ES) cells can be valuable for monitoring differentiation processes and for improving applications in basic developmental biology. The application of ES cells can be a useful tool for drug discovery and toxi-cology. Therefore, we suggest the high-throughput screening (HTS) system based on ES cells in this study. Firstly, we optimized the feeder-free condition and seeding cell number which can maintained for at least 7 days without over-con-fluency. We analyzed the system by cell viability, proliferation activity, RT-PCR and morphologic/immunohistoche-mical evaluations. The optimal cell seeding number was 30/well that was maintained the typical colonial morphology over 9 d with 1,000 U/ml LIF in the limited space. The cell in optimized condition expressed ALP, SSEA-1, Oct 4 and Nanog and the genetic expressions showed similar to protein expressions. The cell lineage marker expressions showed faint or none. The cell viability and proliferation activity were increased in time-dependent manner in our optimized HTS system. In conclusion, the novel HTS system using ES cells can by useful for developing mod-els for drug discovery as well as toxicological screening in the near future.

Keywords: 96-well plate, embryonic stem cell, feeder-free, high-throughput screening