Physics & Astronomy/Chemistry & Biochemistry Lecture: Dr. Lydia Kisley

Science at the ultimate concentration limit – measuring one molecule at a time

A discrepancy exists in physics and chemistry between the way molecular interactions are visualized and how they are commonly experimentally measured. Mechanistically, we often picture one molecule interacting with another and that those interactions can occur in multiple, diverse, or heterogeneous, types of ways.  Yet, the same molecules are experimentally measured as an ensemble, often on the order of 10²³, that obscure heterogeneity. Single molecule spectroscopy allows experiments to parallel our molecular representations in the physical sciences and resolve hidden heterogeneity. Further, single molecule spectroscopy allows super-resolution imaging on the order of 10’s of nanometers using optics, overcoming the limits of traditional, diffraction-limited optical microscopy and the restrictive imaging conditions of electron or atomic-force microscopy. The power of single molecule spectroscopy and super-resolution imaging were recognized by the Nobel Prize in Chemistry for 2014.  The experimental methods for single molecule spectroscopy will be introduced, along with a discussion of applications of super-resolution imaging to two systems: the organization and movement of biomolecules in cells and in analytes within chromatographic chemical separations.