Molybdenum Disulfide Quantum Dots as Dual-Function Catalysts and Coreactants for Enhanced Ru(bpy)32+ Electrochemiluminescence

Abstract

Electrochemiluminescence (ECL) is a powerful tool for clinical diagnosis due to its exceptionally sensitive characteristics. In this work, an enhanced and stable anodic ECL was observed in the suspension of hydrothermally synthesized molybdenum disulfide quantum dots (MoS2 QDs) and ruthenium(II) tris (2,2′ -bipyridyl) (Ru(bpy)32+), which was enhanced more than 80-fold compared to individual Ru(bpy)32+. MoS2 QDs can effectively catalyze the oxidation of Ru(bpy)32+, with amino groups on its surface serving as coreactants. As a result, MoS2 QDs exhibit a high efficiency comparable to tripropylamine (TPrA) for the ECL of Ru(bpy)32+. The possible mechanism of the electrode surface reaction was discussed, while several factors including the pH of the buffer solution and the amount of MoS2 QDs were also investigated, to further confirm the role of MoS2 QDs in the Ru(bpy)32+/MoS2 QDs system. Based on the quenching effect between the excited state of Ru(bpy)32+ in the Ru(bpy)32+/MoS2 QDs ECL system and the oxidized form of dopamine (DA), a DA sensing platform was successfully established, and the DA content in urine was successfully detected (recovery rate 95.90-101.13%).