Real-time assessment of cytotoxicity by impedance measurement on a 96-well plate

In this work cell adhesion and cellular response to metal compounds classified as cytotoxic and carcinogenic are assessed by electrical impedance measurement in a 96-well plate prototype. This system integrates at the bottom of each well interdigitated electrodes to monitor in real time the electrical impedance changes at the electrode/culture medium interface due to cell adhesion, considered as a index of cell viability. The cytotocixity of sodium arsenite, cadmium chloride and cis-platinum is assessed on-line on BALB/3T3 A-31-1-1 cell line, a well known model to evaluate cytotoxicity and carcinogenic potential of chemicals. The inhibitory half concentration (IC50) is calculated from the impedance data normalized to the control and compared with conventional methods used to study basal cytotoxicity of chemicals in BALB/3T3 cell line model, such as colony forming efficiency (CFE) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. The results suggest similar behavior of cytotoxicity induced by tested chemicals assessed by the three tests compared even if CFE remains the more sensitive. However, the impedance-based on-line measuring 96-well plate method is, on our point of view, the less laborious and easier test. The cytotoxicity of cobalt as micron and nanoparticles is also evaluated revealing the possibility for the system to monitor on-line and with high throughput new chemicals.