Porous-Pt-CuO-driven electrochemical biosensor for tracking of endogenous H2S biomessenger molecules

Hydrogen sulfide (H 2 S) is considered to be the third endogenous gas messenger after nitric oxide and carbon monoxide , and is closely related to physiological and pathological functions of human being. Rapid and real-time monitoring of endogenous H 2 S production in living cells is of great significance for clinical diagnoses of related disease and in-depth investigation of pathological processes. The application of electrochemical sensors has become a promising method to achieve real-time H 2 S monitoring comparing to other methods. Up to now, low-cost, and highly sensitive electrocatalysts for H 2 S detection are conspicuously scarce. Herein, we developed a high-efficient method to construct a H 2 S electrochemical sensor, which configure dissolved–H 2 S–sensitive electrochemical sensor using porous Pt-modified copper oxide (Pt–CuO) as electrocatalyst. The obtained sensor possessed remarkable H 2 S detection performance, achieving the detection limit of 0.5 ppm and apparent selectivity toward various gases (e.g., ammonia, nitrogen dioxide , and carbon dioxide). The electrochemical sensor was also applied for monitoring H 2 S released from mesenchymal stem cells. The enhanced sensing performance was attributed to: (1) electrocatalytic reaction between CuO and [H 2 S] (H 2 S and HS − ) was observed in the cyclic voltammetry curves with oxidation current peaks; (2) Pt catalytic activity promoted electron transfer during the detection process and further decreasing Pt–CuO resistance; and (3) enhanced diffusion of detection molecules/ions, which increased the reactivity sites through forming cross porous structures using sodium carbonate as sacrifice template. The proposed Pt–CuO-based electrochemical sensor shows great potential for applications in clinical diagnoses, and provides effective means to understand the role of H 2 S in biological processes.