Towards 3D modelling and imaging of infection scenarios at the single cell level using holographic optical tweezers and digital holographic microscopy.

The analysis of dynamic interactions of microorganisms with a host cell is of utmost importance for understanding infection processes. We present a biophotonic holographic workstation that allows optical manipulation of bacteria by holographic optical tweezers and simultaneously monitoring of dynamic processes with quantitative multi-focus phase imaging based on self-interference digital holographic microscopy. Our results show that several bacterial cells, even with non-spherical shape, can be aligned precisely on the surface of living host cells and localized reproducibly in three dimensions. In this way a new label-free multipurpose device for modelling and quantitative analysis of infection scenarios at the single cell level is provided.