Novel Ru(bpy)(cpaphen)/TPrA/TiO Ternary ECL System: An Efficient Platform for the Detection of Glutathione with Mn as Substitute Target.

A sensitive electrochemiluminescence (ECL) biosensor was developed for glutathione (GSH) detection based on a novel Ru(bpy)(cpaphen)/TPrA/TiO ternary ECL system with Mn as substitute target for signal amplification. Specifically, the TiO nanoneedles (TiO NNs) were used as the coreaction accelerator for the first time to promote the oxidation process of coreactant tripropylamine (TPrA) in the anode and significantly increase the ECL signal of Ru(bpy)(cpaphen) for an amplified initial signal. Meanwhile, a novel target conversion strategy for GSH was developed by reducing MnO nanosheets to Mn as a substitute target, which played the role of a coenzyme factor for cleaving DNA double strands intercalated with Ru(bpy)(cpaphen) to markedly weaken initial signal. As a result, the novel "on-off" biosensor achieved a sensitive detection of GSH range from 5 μM to 215 μM with a detection limit of 0.33 μM. Importantly, the proposed strategy enriched the application of Ru complex and TPrA ECL system in bioanalytical applications, and provided a new signal amplification strategy for bioactive small molecules.