2.4 Cell Preparation
The cells were spun down at 3000 rpm (Hettich EBA 20 Centrifuge) for 5 minutes to remove any residual culture media and resuspended in DEP buffer twice. The cell number was determined using a hemocytometer (Marienfeld). The number of the cells loaded into the electrode array was monocytes 5x105 cells/ml. Live and dead cells were distinguished using the Trypan blue (Sigma-Aldrich), Propidium iodide (PI) (Sigma-Aldrich) and DAPI (Sigma-Aldrich) dyes.
The influence of the low-conductive DEP buffer on glioma cell viability was determined by incubating cells in the DEP buffer for 30 minutes and enumerating the number of live and dead cells before and after the incubation.
Viability of glioma cells for pre- and post-electric field exposures (10 minutes) was determined by staining the cells using 1 µl of PI (Stock: 10 mg/ml) and 1 µl of DAPI (Stock: 10 mg/ml) solutions. Next, we counted both PI and DAPI positive cells as dead cells.