Electroporation of Jurkat Cells in Silicone Oil

Figure 1 shows the experimental setup. The apparatus was fabricated with pin headers and a printed circuit board as described in the previous paper [35 (link)]. The electrodes’ gap was 5.08 mm. The apparatus was filled with 1.5 mL fluorocarbon oil (Fluorinert, 3M, Tokyo, Japan), and then 1 mL silicone oil (KF96-100CS, 100 cSt kinematic viscosity, 2.74 relative dielectric constant, 965 kg/m³ density, Shin-Etsu Chemical, Tokyo, Japan) was added.
Before electroporation, Jurkat cells were harvested by centrifugation (10 min, 200× g, 4 °C) and resuspended in an appropriate electroporation medium. The cell concentration was determined using a Coulter counter (Z2, Beckman Coulter, Brea, CA, USA). The cell suspension (3.0 μL) containing 1.0 × 10⁵ Jurkat cells was dispensed in the silicone oil, and a high voltage was supplied using a DC high-voltage (HV) power supply (HAR-30R10, Matsusada Precision, Kusatsu, Japan). When the applied voltage was set to 3.0 kV, instantaneous short-circuiting could be induced. After short-circuiting, with a distinctive sound, the DC HV power supply was manually turned off.