Human immune cells routinely exert mechanical forces to fulfill their tasks as part of the immune system. Neutrophils and macrophages adhere to other cells, migrate through tissue and internalize extracellular objects. Over the last decades, molecular and cellular biology were very successful in identifying a large number of molecules that are involved in cell adhesion, cell migration and phagocytosis. However the mechanical properties of these important cellular processes are currently just beginning to be unraveled.

We are studying the mechanics of single immune cells on a sub-cellular level by using advanced optical micromanipulation techniques in combination with live cell imaging. Optical tweezers allow us to apply well defined forces very locally to selected cell locations while simultaneous live cell imaging allows us to monitor the cellular responses to these stimuli. Furthermore, optically manipulated microparticles which have biochemically active surface coatings or microparticles which provide a controlled release of molecules allow us to stimulate cells with a high temporal and spatial flexibility. Monitoring the mechanical and biochemical cell responses to these stimulations can reveal the interplay between cellular biochemistry and cell mechanics.

Modern Cell Biology and Systems Biology will integrate this knowledge into mathematical models of cellular systems which combine cellular biochemistry with cell mechanics. Tested models of these systems will not only deepen our basic knowledge in biology, but will also in the case of immune cells lead to a better understanding of the human immune system and potentially new therapeutic approaches.

To enable our cell biological and biophysical studies, we are utilizing and developing new micro- and nanotechnologies for optical manipulation and flexible cell stimulation. Our optical micromanipulation is based on holographic tweezers which allow the simultaneous trapping and positioning of multiple microparticles.