title: Interdependence of initial cell density, drug concentration and exposure time revealed by real-time impedance spectroscopic cytotoxicity assay.
abstract: We investigated the combined effect of the initial cell density (12,500, 35,000, 75,000, and 100,000 cells cm(-2)) and concentration of the anti-cancer drug doxorubicin on HeLa cells by performing time-dependent cytotoxicity assays using real-time electrochemical impedance spectroscopy. A correlation between the rate of cell death and the initial cell seeding density was found at 2.5 μM doxorubicin concentration, whereas this was not observed at 5 or 100 μM. By sensing the changes in the cell-substrate interaction using impedance spectroscopy under static conditions, the onset of cytotoxicity was observed 5 h earlier than when using a standard colorimetric end-point assay (MTS) which measures changes in the mitochondrial metabolism. Furthermore, with the MTS assay no cytotoxicity was observed after 15 h of incubation with 2.5 μM doxorubicin, whereas the impedance showed at this time point cell viability that was below 25%. These results indicate that impedance detection reveals cytotoxic events undetectable when using the MTS assay, highlighting the importance of combining impedance detection with traditional drug toxicity assays towards a more in depth understanding of the effect of anti-cancer drugs on in vitro assays. Moreover, the detection of doxorubicin induced toxicity determined with impedance under static conditions proved to be 6 times faster than in perfusion culture.
authors: Department of Micro- and Nanotechnology, Technical University of Denmark, Kgs. Lyngby, Denmark. jenny.emneus@nanotech.dtu.dk.
authors: C
authors: C
authors: Caviglia
authors: K
authors: K
authors: Zór
authors: S
authors: S
authors: Canepa
authors: M
authors: M
authors: Carminati
authors: L B
authors: LB
authors: Larsen
authors: R
authors: R
authors: Raiteri
authors: T L
authors: TL
authors: Andresen
authors: A
authors: A
authors: Heiskanen
authors: J
authors: J
authors: Emnéus
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D002452:Cell Count; D002470:Cell Survival / Q000187:drug effects; D058266:Dielectric Spectroscopy / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D004317:Doxorubicin / Q000494:pharmacology*; D004354:Drug Screening Assays, Antitumor / Q000379:methods*; D006367:HeLa Cells; D006801:Humans; D013997:Time Factors
chemical_list: D000970:Antineoplastic Agents; D004317:Doxorubicin