CuFe Cooperativity at the Membrane-Electrode Interface Elicits a Tandem 2e+2e Mechanism for Exclusive O-To-HO Electroreduction.

High O reduction reaction (ORR) kinetics and exclusive 4e pathway selectivity are keys to realizing a sustainable society. However, nonprecious electrocatalysts at present cannot enhance the ORR turnover frequency and HO Faradaic efficiency (FE) concurrently. To address these two challenges, hybrid bilayer membrane (HBM) electrodes with earth-abundant metal centers are developed to control proton-coupled electron transfer (PCET) in ORR.

Activity-Based Sensing of Ascorbate by Using Copper-Mediated Oxidative Bond Cleavage.

Ascorbate is an important biological reductant and enzyme cofactor. Although direct detection through ascorbate-mediated reduction is possible, this approach suffers from poor selectivity due to the wide range of cellular reducing agents. To overcome this limitation, we leverage reduction potential of ascorbate to mediate a copper-mediated oxidative bond cleavage of ether-caged fluorophores.

Fluorescein-Containing Superoxide Probes with a Modular Copper-Based Trigger.

Fluorescein-derived superoxide probes featuring a copper(II) complex that can be activated by superoxide to initiate ether bond cleavage and uncage a fluorescein reporter for imaging in live cells are described. Compared to other superoxide sensing moieties, this bond cleavage strategy can be modularly adapted to fluorescent reporters with different properties without compromising the superoxide reactivity and selectivity. A green-emitting probe and its lysosome-targeting analogue have been successfully developed.

Zinc excess increases cellular demand for iron and decreases tolerance to copper in .

Transition metals serve as an important class of micronutrients that are indispensable for bacterial physiology but are cytotoxic when they are in excess. Bacteria have developed exquisite homeostatic systems to control the uptake, storage, and efflux of each of biological metals and maintain a thermodynamically balanced metal quota. However, whether the pathways that control the homeostasis of different biological metals cross-talk and render cross-resistance or sensitivity in the host-pathogen interface remains largely unknown.

A modular trigger for the development of selective superoxide probes.

We report here a new bioinspired copper-based strategy of superoxide sensing and the development of sensitive (>90-fold fluorescence turn-on) and selective superoxide probes for imaging variations in the endogenous superoxide level in various live mammalian cells (HEK293T, HeLa and A431).

Copper-based reactions in analyte-responsive fluorescent probes for biological applications.

Copper chemistry has been capitalized on in a wide spectrum of biological events. The central importance of copper in biology lies in the diverse chemical reactivity of the redox-active transition metal ranging from electron transfer, small molecule binding and activation, to catalysis. In addition to its many different roles in natural biological systems, the diverse chemical reactivity of copper also represents a rich opportunity and resource to develop synthetic bioanalytical tools for the study of biologically important species and molecules.