A simplified colorimetric method for rapid detection of cell viability and toxicity in adherent cell culture systems

Evaluation of cell viability and toxicity in adherent culture systems is of critical relevance for a wide range of disciplines of biomedical sciences research, including cancer research, toxicology, pharmacology, cell biology, neurology and nanomedicine. Several well-established cytotoxicity assays are widely used by researchers, including the most-preferred MTT assay. Nevertheless, there are problems associated with them, for example; in terms of the time-factor and solubilization of the formzan crystals before its spectroscopic quantification. In this study, we propose a simple, fast and cost-effective colorimetric assay that is free of these issues.

Our assay was based upon reductive splitting of blue-green colored supravital safranin derivative dye Janus green B (JG-B) to pink colored diethyl safranin by oxidoreductases of the electron transport chain (ETC) of actively respiring mitochondria. Because this conversion can be easily and reliably followed spectroscopically, measure of diethyl safranin formed from extraneously added JG-B provides a proficient indicator of cellular health and viability.

Using MCF-7, a breast cancer cell line, we provide a proof of concept for the suggested assay and compare it with the MTT assay.

Unlike the MTT assay, our JG-B assay does not require a solubilization/extraction step, and hence follows a much simpler and time-efficient protocol suitable for high-throughput analysis of cell viability in anchorage-dependent cell culture models. Additionally, the JG-B cell viability assay reported here can be suitably applied either independently or in complementation with other assays for the analysis of cellular viability and toxicity in both analytic and therapeutic aspects of research.