Using the HoloMonitor time-lapse cytometer, cell death and viability can be monitored over time without fluorescent labeling or other treatments. Unlike traditional microscopy, the HoloMonitor provides quantitative data on parameters such as cell area, thickness and volume, which are useful in detection of live/dead cells.

Holographic microscopy has successfully been used in cell death/viability studies. The optical cell volume and the optical thickness of a dying cell change over time. Healthy cells are often irregular in shape and thin, dying cells are round and thick while dead cells are round and thin. Several authors have observed a large decrease in optical cell volume during cell death. Living/dead cells have been detected equally well using cell roundness and cell thickness parameters as with fluorescence-based methods.

While volume is an efficient parameter to detect dead cells in homogeneous cell populations, it is not optimal for heterogeneous cell populations due to the overlap in volume between small living cells and large dead cells. HoloMonitor presents alternative parameters to volume, such as optical thickness, area and irregularity.

In this application note we show how the HoloMonitor can be used in viability analyses of populations by monitoring and characterizing cell morphology of individual cells during treatment with an apoptosis-inducing drug. The acquired data are then used for further viability analyses of populations. The viability analysis performed using HoloMonitor was compared to manual cell counting using a haemocytometer and trypan blue staining of dead cells.