November 18
@
12:00 PM
–
1:00 PM
The Role of Symmetry in Chemically Selective Microscopy of Biological Assemblies
Garth J. Simpson, PhD
Professor of Chemistry
Research Director; Young Advanced Manufacturing of
Pharmaceuticals Institute
Purdue Director; NSF Center for Bioanalytic Metrology
Purdue University
Abstract:
Orientational ordering often defines practical function within biological systems, including molecular packing within bilayer structures that define cell membranes and protein assemblies providing structural integrity within tissues. The impact of ordering is particularly interesting in chiral assemblies, in which orientational order and local symmetry can dramatically increase the magnitude of chiral-specific spectroscopy and microscopy measurements of ordered systems through mechanisms not present in isotropic assemblies. Not only do these effects create opportunities for new interpretations of existing measurements, they suggest possibilities for envisioning new experimental approaches for interrogating molecular ordering at biological interfaces and within ordered biological assemblies leveraging the inherent chirality within living systems. Coherent nonlinear optical interactions such as second harmonic and sum-frequency spectroscopy are now well established probes of chirality within ordered assemblies. Building on this prior framework as a launchpad, novel tools specifically leveraging incoherence in light-matter interactions for chiral-specific spectroscopy will be described and assessed. These novel spectroscopic approaches have the potential to uniquely inform on structure/function relationships in biological assemblies.