Affiliation: UNC Chapel Hill
Seminar title "Droplet Like It’s Hot: Electrochemistry under Nanoconfinement"
Host: Dr. Anne Co
Short Bio (also attach my recent CV): Jeffrey E. Dick earned a BS in Chemistry from Ball State University and a Ph.D in Chemistry at the University of Texas at Austin under the guidance of Allen J. Bard. Jeffrey began his independent career at the University of North Carolina at Chapel Hill in July 2018. At UNC, Jeffrey’s group focuses on nanoelectrochemical tools to study reactivity in very small volumes, from aqueous nanodroplets to single, living cells.
Abstract: The volume of the ocean is 1021 L (zettaliter); however, the volume of a lysosome, an organelle tasked to drive key cellular pathways, is 10-18 L (attoliter). Despite variations in volume that span nearly 40 orders of magnitude, chemical reactions are often assumed to proceed at the same rates. Measurement science is lacking to rigorously probe reactivity in volumes down to 10-18 L. Mass spectrometric techniques have elucidated enhanced reactivity in sub-micrometer droplets during electrospray. However, electrospray creates a polydispersity of droplet sizes, and a rigorous evaluation of chemical rates as a function of droplet size is difficult. While fluorescence measurements can probe reactivity in single nanodroplets, measurements are often limited to a small library of fluorophores that do not appreciably photobleach during analysis. To understand rates as a function of droplet size, techniques are required to study single sub-micrometer droplets. This talk will detail our group’s efforts to develop nanoelectrochemical tools to study reactivity in aqueous nanodroplets. When an aqueous nanodroplet filled with an analyte of interest irreversibly adsorbs onto an ultramicroelectrode surface, reactivity within that single aqueous nanodroplet can be tracked with electrochemistry. Intricate reactions, such as the electrodeposition of high entropy alloy nanoparticles and enzymatic turnover, can be probed in a very quantitative fashion with the aid of finite element simulations. These experiments allow the electrodeposition of high entropy alloy nanoparticles and have demonstrated enzymatic turnover rates are orders of magnitude faster in aqueous nanodroplets compared to bulk solutions.
