mixed sample
Protocols: HeLa (RCB0007, RIKEN BRC), NIH/3T3 cells (RCB2767, RIKEN BRC)  were maintained in Dulbecco's Modified Eagle Medium (DMEM, 08456-65, Nacalai Tesque). The culture medium was supplemented with 10% fetal bovine serum (FBS, 26140-079, gibco) and 1% penicillin-streptomycin (P/S, P4333-100ML, Sigma-Aldrich). Prior to on-chip imaging and library preparation, cells were suspended in 200 μL Gene Pulser® Electroporation Buffer with 100 nM DNA tags and performed electroporation using Gene Pulser MxcellTM Electroporation System (Bio-Rad) with the following parameters: voltage of 250 V, capacitance of 2000 μF, resistance of: ∞ Ohm, duration of 20 ms for HeLa, voltage of 350 V, capacitance of 950 μF, resistance of ∞ Ohm, duration of 20 ms for NIH/3T3. Subsequently, we added 1 mL medium and cultured overnight in 24-well plate dishes, each containing cells with one of 16 different types of DNA tags. We treated the cells with palbociclib (S4482, Selleck Chemicals LLC) at various concentrations with 0.1% dimethyl sulfoxide for 24 h. After washing with 1× phosphate-buffered saline (PBS, 14249-24, Nacalaitesque), the cells were stained individually in each well with 16 different combinations of four CellTrace (2.5 μM Violet, 1 μM CFSE, 2.5 μM Yellow, and 0.2 μM Far Red) according to the manufacturer's protocol. We then suspended the 16 sub-pools of cells in a tube of imaging medium (DMEM, 08490-05, Nacalai Tesque, without FBS and P/S) at equal concentrations.