Reduction of Ammineruthenium(III) by Sulfide Enables In Vivo Electrochemical Monitoring of Free Endogenous Hydrogen Sulfide

Abstract

The discovery of endogenous sulfide in mammalian brain opens up a door to understanding of the physiological function of hydrogen sulfide (HS). The transformation of different forms of sulfide (i.e., S, HS, HS, bound sulfane sulfur, et al.) in various physiological conditions hurdles the direct detection of hydrogen sulfide in vivo. Here, we find that ammineruthenium(III) (Ru(NH)) can catalyze the electrochemical oxidation of free sulfide including HS and HS in a neutral solution (pH 7.4). This property is used to constitute an electrochemical mechanism for selective detection of hydrogen sulfide. By coupling in vivo microdialysis with selective electrochemical detection, we successfully developed an integrated microchip-based online electrochemical system (OECS) for continuous monitoring of free endogenous hydrogen sulfide in the central nervous system (CNS). The microchip-based OECS is well responsive toward hydrogen sulfide with high stability, sensitivity and selectivity. Compared with the existing methods, the OECS does not require offline treatment of brain tissue or adjustment of the detection solutions into acidic or strong basic atmosphere. These priorities essentially enable the system to accurately and reliably track dynamics of hydrogen sulfide in the CNS.

Controlled‐Potential‐Based Electrochemical Sulfide Sensors: A Review

“… The EC' reaction between Ru(NH 3 ) 6 3+ (oxidant) and H 2 S (reductant) with resultant CV curves at a scan rate of 10 mV s −1 in 0.1 M phosphate buffer containing 1 mM Ru(NH 3 ) 6 3+ in the absence (black curve) and presence (red curve) of sulfide. Reproduced with permission [95] . Copyright 2017, American Chemical Society.…”

“…Recently, Shujun et al used an EC'-based amperometric method for sensitive and selective determination of free endogenous H 2 S at an applied potential of 0 V (vs Ag/AgCl) with a microchip-based online electrochemical system (OECS). [95] The authors reported ammineruthenium(III) (Ru-(NH 3 ) 6 3 + ) as an electron mediator for electrochemical oxidation of sulfides in 0.1 M pure phosphate buffer solution (pH 7.4). A microchip-based OECS was developed with ITO electrodes for uninterrupted monitoring of sulfide in the central nervous system.…”

Characteristics and Treatment of Wastewater from the Mercaptan Oxidation Process: A Comprehensive Review

“…Using sulfuric acid with a pH of up to 5, and 70 • C, a little more than 90% of the dissolved H 2 S changes to the gas phase. From this pH, the conversion to dissolved sulfide (S 2− ) is minimal [48]. These authors were the first to report this pretreatment process.…”

Rational Design of Specific Recognition Molecules for Simultaneously Monitoring of Endogenous Polysulfide and Hydrogen Sulfide in the Mouse Brain

“…[7] Recently, Zhang et al developed an electrochemical sensor for in vivo monitoring of H 2 Satalow potential of À0.19 V(vs.Ag/AgCl) in the brain by applying ammineruthenium (III) to catalyze the electrochemical oxidation of H 2 Si nan eutral solution. [8] However,ak ey issue about electrode contamination should be carefully considered based on the electrochemical oxidation of H 2 Sbecause the oxidation product of H 2 S, sulfur (S), is strongly adsorbed onto the electrode surface to poison the electrode,r esulting in low reproducibility and big determination error. Therefore,i ts till renders ag reat challenge to design an efficient sensing strategy to simultaneous assay of H 2 S n and H 2 Swithout cross-talk and electrode contamination.…”