Professor Ellen Sletten

Professor Ellen Sletten
Department of Chemistry & Biochemistry
University of California, Los Angeles
Host: Professor Mark Distefano
Abstract

Polymethine fluorophores for in vivo shortwave infrared imaging

Fluorescence imaging is a central tool for visualizing complex biological systems, yet the contrast and resolution attainable in vivo is limited by diffuse light originating from background and scattering at visible and near-infrared (NIR) wavelengths. Recently, the shortwave infrared region of the electromagnetic spectrum (SWIR, 1000 – 2000 nm) has emerged as an optimal region for in vivofluorescence imaging due to its minimal light scattering and low tissue autofluorescence compared to the NIR. While the SWIR demonstrates great promise, suitable materials are needed with emission at these low energies for the development of optical contrast agents. Our group develops biocompatible polymethine fluorophores for the shortwave infrared region. In 2017, we discovered a bright shortwave infrared emitter containing flavylium heterocycles that we deemed Flav7. Since that time, we have systematically investigated Flav7 using physical organic chemistry approaches and can now predictably tune the absorption and emission properties. These insights have lead to new SWIR fluorophores that enable multiplexed in vivo imaging and the fastest SWIR imaging to date.

Research

Professor Ellen Sletten's research group applies the fundamental principles of physical organic chemistry to create enhanced nanotherapeutics and diagnostics, new chemical tools to study living systems, and novel light-harvesting materials. The central theme of her group is the element fluorine, which imparts unique, orthogonal behavior to molecules and materials. Research within the group involves an interdisciplinary mix of organic synthesis, fluorous chemistry, chemical biology, self-assembly, polymer synthesis, photophysics, nanomedicine, and pharmacology. 

Professor Sletten

Professor Sletten received her bachelor's degree from Stonehill College, and her doctorate at the University of California, Berkeley. Her thesis work involved the optimization and development of bioorthogonal chemistries and their subsequent applications in labeling living systems. She performed her post-doctoral studies at the Massachusetts Institute of Technology. She joined the faculty at UCLA in 2015.