Speaker Institution : University of California-San Diego
Title: New microfluidic devices and materials for chemotaxis and mechanobiology
Chemotaxis of adherent cells in gradients of chemoattractants is an important process in inflammation and development. Microfluidic devices provide gradients with various well-defined shapes, making it possible to study chemotaxis quantitatively. I will present results of studies of chemotaxis of popular model organisms, the social amoeba, D. discoideum, and neutrophil-like HL60 cells, using various microfluidic devices built in my lab. These experiments tested the mechanisms of chemotactic response, limits of chemotactic sensitivity, and roles of spatial and temporal cues in the chemotaxis. Many types of mammalian cells in their native environments are exposed to periodic stretching that is a strong mechanical cue. I will present a microfabricated device, in which cells plated on a thin elastomeric membrane are stretched by up to 15%, while being continuously monitored under a high resolution fluorescence microscope with widefield, confocal, or TIRF illumination. Finally, I will present experiments on adherent mammalian cells plated on thin layers of soft silicone gels with high refractive indexes. Mechanical forces exerted by cells on the substrates are measured using traction force microscopy, and fluorescent biomarkers in the cell adhesion complexes are visualized with TIRF microscopy