Description
Flyer: Brandon Jolly and Yi Chen Flyer
Speaker: Brandon Jolly
Title: Spatial Control in Multi-step, Multi-catalyst Organometallic Processes
Abstract: Spatial localization is one method in which biology manages its complex network of multi-step and/or multi-catalyst processes. For example, encapsulation of enzymes via compartmentalization allows for the efficient generation and utilization of intermediate species along a biochemical pathway. Much work has been devoted to applying compartmentalization for efficient in vitro enzyme cascades both theoretically and experimentally. However, only recently has attention been given to spatial localization in the context of organometallic catalysis experimentally, with no theoretical insights. Therefore, we developed a kinetic model to evaluate and understand the effect compartmentalization may have on a multi-step organometallic process, such as a typical catalytic cycle. A key design principle born out of this work is that compartmentalization is predicted to benefit organometalic catalysis if diffusion into/out of the compartment is kinetically comparable to, or slower than the catalytic cycle itself, which is tunable via compartment morphology. Next, we then set out to extend the concept of spatial localization in organometallics to multi-catalyst processes. Specifically, electrocatalytic CO2 reduction integrated to Pd catalyzed polyketone synthesis was chosen as a target multi-catalyst system that may benefit from spatial control. Ultimately, we demonstrate the generation and consumption of CO from CO2 reduction to co-polymerization with ethylene in one pot, with external control over %CO incorporation into the polymer via applied current, which is unattainable without spatial control.
Speaker: Yi Chen
Title: Generate Gradient in Electrochemical Microfluidic Systems to Investigate P. Aeruginosa Metabolic Regulation Kinetics on Single Cell Level
Abstract: Comprehending how bacterial metabolism adapts to environmental changes, like oxygen abundance variation, is important in microbial ecology and has potential applications in disease treatment and bacterial infection. Previous research primarily centered on the collective regulatory responses in bulk culture study while single-cell level understanding of bacterial regulation kinetics still remains a challenge. To address the challenge, we developed an electrochemical microfluidic system to generate microscopic oxygen and hydrogen peroxide concentration gradients, simulating the intricate micrometer-scale environments inhabited by bacteria. Particularly, we cultivated P. aeruginosa in the generated oxygen gradient and investigated its metabolic regulation kinetics on single-cell level, specifically with regard to the concentration of adenosine triphosphate (ATP), in response to environmental oxygen spatial variation and temporal oscillation.