For real-time cell analysis (RTCA), the xCELLigence® multi-plate (MP) instrument (ACEA Biosciences; California, US) with integrated (RTCA Software 2.1.0) software was used to determine Cell Index (CI) which is considered a proxy for cytotoxicity. The MP RTCA instrument has 6 cradles which allows 6 plates to be run simultaneously, with 3 samples per 96 well plate. The bottom of each 96 well E-Plate® contains a set of gold microelectrodes, attached to each well which allows the passing of an electric current. CI measures the electrode impedance at the electrode/solution interface, which is influenced by the presence of cells cultured in the wells and thus impeding electron flow.
As described in the manufacturer’s protocol, E-Plates® were seeded (20,000 cells/well H292 s and 10,000 cells/well HGFs [11 (link)] and allowed to settle for 30 min before a background measurement was taken. Cells were allowed to proliferate for 24 h before dosing with test article for 24 h. Impedance (Cell Index) measurements were taken throughout the 48 h time period, producing a cell viability curve once analysed. 0.25 % (v/v) concentration of Triton-X100 was used to anchor curves when full cytotoxicity was not gained by the test article.
As described in the manufacturer’s protocol, E-Plates® were seeded (20,000 cells/well H292 s and 10,000 cells/well HGFs [11 (link)] and allowed to settle for 30 min before a background measurement was taken. Cells were allowed to proliferate for 24 h before dosing with test article for 24 h. Impedance (Cell Index) measurements were taken throughout the 48 h time period, producing a cell viability curve once analysed. 0.25 % (v/v) concentration of Triton-X100 was used to anchor curves when full cytotoxicity was not gained by the test article.