Rheological behavior of real tissue cells and the extracellular matrix (ECM) shares many characteristics of gels made from purified biopolymers. Due to the difficulty in imaging the individual biopolymers in a 3 dimensional network, very little has been done to experimentally investigate how the deformations and rearrangements of individual filaments lead to the unique properties of these biopolymer networks. Moreover, the tissue cells are found to be able to “measure” the mechanical properties of their ECM. This phenomenon sparkled many interesting physics questions. For example, what is the time scale that cells take “rheological” measurements on the ECM? I will present experiments to fabricate novel materials that can be applied to search for the molecular mechanism that leads to unique properties of the semiflexible polymer networks. And, I will also provide examples of applying the micro-fabricated materials to investigate how mechanical properties of extracelluar matrix regulate the function of tissue cells. Qi Wen is a post-doc at the University of Pennsylvania. He obtained his Ph.D. degree in Biological Physics from Brown University in 2007.