Phase-contrast

Intensity describes optical path length (dependent on thickness and refractive index of sample). Allows high contrast imaging with low light intensity, minimising photo damage to cells. Artefacts such as white halo around objects may help with segmentation of individual cells.

Fluorescence

Bacteria labelled with mCherry fluorescent protein. Allows bacteria to be localised during and after engulfment.

Images taken at intervals of one minute over three days.

Imaging Example

Next: Segmentation