(Invited) In Vivo Electrochemical Monitoring of Free Endogenous Hydrogen Sulfide

Abstract

Increasing researches have demonstrated that hydrogen sulfide is an important neuromodulator in the CNS and the third gasotransmitter joined with nitric oxide and carbon monoxide. It not only protects neurons and gila, and induces hippocampal long-term potential, but also is related to CNS diseases, such as Alzheimer’s disease, Parkinson’s disease, ischemic stroke and traumatic brain injury. Although there are some methods to determine hydrogen sulfide, the transformation of different forms of sulfide (S2-, HS-, H2S, bound sulfane sulfur et al.) and the chemical instability (easily oxidized) of hydrogen sulfide in physiological conditions render a great challenge to in vivo track accurately of the free hydrogen sulfide in the brain under the physiological condition. Motivated by this need, we are dedicating to develop in vivo electrochemical method for selective monitoring free hydrogen sulfide in the brain. Based on the specific H2S-induced chemical reaction (i.e. precipitate metals salts), we synthesized an electrochemiluminescent (ECL) probe and developed a reaction-based turn-on ECL sensor to selectively detect extracellular hydrogen sulfide in the microdialysate of rat brain taking advantage of the volatile property of hydrogen sulfide. More recently, we find one electrochemical mechanism that ammineruthenium(III) (Ru(NH3)6 3+) can catalyze the electrochemical oxidation of free sulfide including both forms of HS- and H2S in a neutral solution. Based on our mechanism, we developed one simple and effective method to in vivo track the dynamic of free hydrogen sulfide in the free moving animal, which can’t reach by other developed probes and methods. These methods open a new opportunity and offers a simple and effective platform for investigations of hydrogen sulfide in physiological and pathological processes.