Calendar of Events

Dr. Cole A. DeForest, Division of Chemistry and Chemical Engineering, California Institute of Technology
Pasadena, CA

There is a growing interest in understanding how a cell senses its micro-environment and how these external cues influence important cellular functions. Such information may be particularly important from a fundamental perspective (e.g., defining the stem cell niche), as well as from the applied viewpoint of re-generating functional tissue equivalents. Though both chemical and mechanical signals have been implicated in dictating local cell behavior, isolated effects are difficult to assess in vivo due to the myriad of uncontrollable, ever-changing cues. In addition, many of these cues are presented in spatiotemporally-complex patterns. To better understand how cells receive instructive in-formation from their extracellular niche, synthetic environments including hydrogels have proven beneficial at assaying cell function in well-defined systems where single cues can be introduced and subsequent effects can be individually elucidated. Unfortunately, few 3D culture platforms allow the experimenter to recapitulate the heterogeneous and dynamic nature of the native tissue environment through 4D control of the material properties in both time and space. In this work, we demonstrate that by utilizing multiple photoreactions that are each initiated with different wavelengths of light, we can independently induce changes to the local physical and chemical material properties at specific locations within a hydrogel culture platform to direct real-time changes in cell function. This talk will detail the syn-thesis and characterization of these dynamically-tunable hydrogel materials and will highlight several examples where user-triggered alterations in the cellular niche can be used to both better understand and direct stem cell fate.