Lectures & Events

Chemical and Biological Physics Special Seminar

Light scattering limits the quality of optical imaging of unlabeled biospecimens: too little scattering and the sample is transparent, exhibiting low contrast, and too much scattering washes the structure information altogether. Recent advances in QPI, an approach by which the pathlength shifts induced by a specimen are mapped at each point in the field of view, allow us to connect the two regimes. We developed spatial light interference microscopy (SLIM) as a high-sensitivity, high-resolution QPI method, which open new applications for studying structure and dynamics. SLIM provides interesting data on cell growth and intracellular transport, specifically, it distinguishes between random and deterministic cargo motion. We measured subtle vesicle transport changes following optogenetic stimulation of live cells. Based on principles of holography, we developed a new optical technique for measuring cell traction. We performed simultaneous measurements of cell growth and cellgenerated forces and showed their evolution during cell differentiation. However, SLIM works best for thin specimens, such as single cell layers and tissue slices. To expand this type of imaging to thick, multiply scattering media, we developed gradient light interference microcopy (GLIM). GLIM is capable of suppressing the incoherent background due to multiple scattering. We demonstrate the use of GLIM to image various samples bovine embryos and live brain slices. Intrinsic dynamic markers promise to provide information about embryo viability, prior to implantation. Quantitative Light Imaging Laboratory, University of Illinois at Urbana-Champaign

Chemistry Colloquium

MIT

Chemistry Colloquium

College of Chemistry, Jilin University, China