Circumventing the Diffraction Limit to Observe Nanoscale Protein Interactions

Due to the near transparency of cells, optical imaging is well suited for studying live or intact cells. Tagging cellular components with fluorophores dramatically extends these capabilities by providing molecular specificity and improved contrast. However, the light microscope is limited by diffraction to ~ 300 nm, whereas many important events for cell function and signaling involve interactions of proteins that occur at the ~ 10 nm scale. I will discuss methods for circumventing the diffraction limit using single molecule fluorescence imaging and quantitative analyses to extract biologically meaningful information from noisy images. The concepts of (super)resolution, classical and quantum limits of estimation, and Bayesian inference will form the backdrop of the discussion