Optimization of electroporation in CMK cells. (A) CMK cells were incubated with a FITC-labeled siRNA molecule and left untreated or electroporated at 300 V, 100 μsec, 2 pulses. After 48 hours cells were analyzed for FITC incorporation by flow cytometry. (B) CMK cells were treated as in panel A and stained with propidium idodide. Viability as measured by PI exclusion was determined by flow cytometry on a Guava Technologies flow cytometer. (C) CMK cells were incubated with 0, 500, or 1000 nM siRNA targeting GAPDH and electroporated as in panel A. After 48 hours cell lysates were subjected to immunoblot analysis for GAPDH and β-actin.