Quantitative measurement of permeabilization in living cells by terahertz attenuated total reflection

Using Attenuated Total Reflection (ATR) imaging technique in the terahertz domain, we demonstrate non-invasive, non-staining real time measurements of cytoplasm leakage during permeabilization of live MDCK cells by saponin at low concentration. The origin of the contrast observed between cells and culture medium is addressed by both experimental and theoretical approaches, and demonstrated to give access to permeabilization dynamics for two close saponin concentrations (50 and 75 μg/ml).