Cytotoxicity and Cell Viability

Cytotoxicity and Cell Viability Assays
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Cytotoxicity is the quality of being toxic to a cell. Assessing the effect of novel drugs or therapies on in vitro cell viability and health is critical to ensure a treatment is safe and effective. There are many types of cytotoxicity and viability assays available for primary, stem cell-derived, cancer, bacterial, or virus-infected cell culture. When deciding on an assay, some things to consider are:

  • >> Are my dyes or reagents toxic? Do they interfere with the biology I wish to study?
  • >> How do I know which endpoints are needed?
  • >> How complex is the assay and how much hands-on time will it require?
  • >> How much are the reagents, plates, and cells?

The Maestro impedance assay offers a simple solution to those questions. No dyes or complex handling. One plate reveals the full cellular response in one simple assay.

Capture the full time-course of in vitro cytotoxicity and cell viability with a simple live-cell assay

Are you working with precious cells, antibodies, patient samples, or compound? Do you have the time required to repeat an assay over multiple time points? Endpoint assays only provide a snapshot of what your cells are doing. To see the full cytotoxic response you need time, money and effort to repeat your experiment over multiple plates and cells. The Maestro impedance assay captures everything on one plate; revealing not only the degree but also the kinetics of cell death. See the Technology tab for more information on how impedance works.

Cells growing to confluence over microelectrode array
Dose response curves: get the best fit for your data

The cytotoxicity of a treatment depends on the delivered dose. With increasing concentration of Dox, the real-time resistance (left) and cytolysis (middle) curves show increased cytotoxicity. The cytolysis was evaluated as a function of the concentration (right) and fit according to the Hill equation. The analysis estimates the 50% effective concentration (EC50) of Dox to be 0.43 micromolar at 72 hours post-dose.

Resistance measurements over time at different doses
Cytolysis data for dose response
Dose response curve

(Left) SKOV3 cancer cells were cultured at 5k cells per well in a CytoView Z 96-well plate. After 24 hours of culture, the SKOV3 cells were dosed with Dox at 9 concentrations in half-log increments from 0.01 to 100 micromolar. The highest concentrations of Dox produced the lowest measured resistance over time. (Middle) The Dox treated wells were compared with the “No Treatment Control” condition to compute cytolysis. The cytolysis was higher for increasing concentrations of Dox. (Right) The Hill equation was fit to the cytolysis data at 72 hours post-dose. The EC50 in this assay was 0.43 micromolar according to the dose response analysis.

Reliable and robust, Maestro cell viability assays correlate with traditional endpoint assays

The number of cells directly scales with impedance. The correlation is so robust it can meet ISO 20391-2 standards for reproducibility. When compared to a traditional viability endpoint, like an MTT assay, the results directly correlate. In vitro cell viability assays on the Maestro Z, however, are not limited to a single time point.

After application of doxorubicin, the impedance measurements revealed the dynamic response of the A549 cells
Evaluation of cell viability 30 post dosing of potentially cytotoxic drugs
The percent cytolysis was tracked in real-time throughout the time course of the response.

(Left) Calu-3 cells plated from 6400-51200 cells/well as measured by the Maestro Z. (Middle) 4 hours after plating impedance measurements show a linear relationship that directly correlates with (Right) optical MTT assay results.


Quickly calculate cytolysis and kill time50%
After application of dox, the impedance measurements revealed the dynamic response of the A549 cells
Evaluation of cell viability 30 post dosing of potentially cytotoxic drugs
The percent cytolysis was tracked in real-time throughout the time course of the response.

(A) 24 hours after plating, Dox is applied and recorded for an additional 36 hours. (B) Dox effect at 30 hours post-dose. (C) Using on-plate controls for cell growth (No Treatment) and death (Tergazyme), the percent cytolysis was tracked in real time throughout the experiment and kill time50 was calculated.

The figures above highlight the dynamic cytotoxic response over time. The percentage of cytolysis, or cell death, can be tracked in real time, and the time to 50% cell death (kill time50) provides insight into the kinetics and efficacy of a treatment's cytotoxicity. 

All products and application data are for research use only and not intended for human diagnostic or therapeutic uses.

Applications & Maestro Z Benefits

Applications of cytotoxicity and cell viability assays:


Why measure in vitro cytotoxicity and cell viability with Maestro Z?

  • >> Analyze the kinetics and capture cytotoxic responses that take minutes to weeks.

  • >> Research the biology, not the chemistry. No dyes or reagents to interfere.

  • >> More data, less work. One plate for the whole experiment.

  • >> Up to 96 wells, save time, cells, media and compound

  • >> No complicated assay protocols, just simple cell culture techniques.

  • >> Sensitive and reliable. Maestro Z can meet the high reproducibility standards of ISO 20391-2

Assay Steps
Cytotoxicity protocol assay steps

Getting started with Maestro Z, Pro, and Edge couldn't be easier. Culture your cells in an Axion multiwell CytoView-Z plate (Hour 0). Load this plate into the Maestro system and allow the environmental chamber to automatically equilibrate. Observe cells adhering to the plate and proliferating as changes in the recorded impedance signal (Hour 0 to 24-72). Add test compounds as required. Track changes in cell viability in the CytoView-Z plate label-free and in real-time with the Impedance Module software.



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