Ximedica 1 article published in JoVE Bioengineering Planar Gradient Diffusion System to Investigate Chemotaxis in a 3D Collagen Matrix David A. Stout1, Jennet Toyjanova2, Christian Franck3 1Department of Mechanical and Aerospace Engineering, California State University, Long Beach, 2Ximedica, 3School of Engineering, Brown University Cell migration is an important part of human development and life. In order to understand the mechanisms that can alter cell migration, we present a planar gradient diffusion system to investigate chemotaxis in a 3D collagen matrix, which allows one to overcome modern diffusion chamber limitations of existing assays.