This is the website of the Soft Matter Physics Division (Physik der weichen Materie) of the University of Leipzig. Our research is dedicated to the broad field of biological physics. In particular, our work focuses on the study of mechanical properties and behavior of polymer networks as well as whole biological cells. It is our primary objective to investigate the underlying physical mechanisms responsible for the observed active and passive behavior of biological soft matter. Special attention is given to the exploration of cancer as well as neuronal growth. Our methods and instruments used to manipulate and characterize polymers, polymer networks, cells and tissues include fluorescence microscopy, optical tweezers, optical stretchers, rheometer, micromanipulators, and scanning force microscopy.