Measuring biophysical properties of living cells with digital holographic microscopy

Quantitative Phase Imaging techniques including digital holographic microscopy (DHM) have emerged recently in life sciences and can be aimed at monitoring and quantifying, in a non-invasive way, cellular processes. Due to its interferometric nature, the DHM phase signal, which depends on both cell thickness and integral RI can be measured with a high sensitivity. However, this dual origin makes its interpretation in terms of the underlying cell process difficult. Consequently, we propose a dual wavelength digital holographic microscopy setup to measure in a single shot fashion cellular thickness and integral RI of living cells. The method is based on the use of an absorbing dye inducing a high RI dispersion in the extracellular medium at the two recording wavelengths. Consequently, from the two quantitative phase signals, measured for the two wavelengths, Posters cellular RI and thickness can be unambiguously calculated.