Integrating resonance energy transfer with redox reaction for highly sensitive electrochemiluminescence sensing of glucose

Facile and rapid monitoring of blood glucose (Glu) is of great significance in clinical diagnostics. Herein, a highly sensitive electrochemiluminescence (ECL) sensor with simplicity and rapidity was designed for reliable Glu assay based on resonance energy transfer (RET) and redox reaction. Initially, Ru(bpy)₃²⁺ encapsulated in dendritic mesoporous silica nanoparticles (RuDMSN, donor) was coated with methylene blue (MB, acceptor/quencher) to form RuDMSN@MB nanocomposites. The incorporation of both donor and acceptor within a single nanostructure resulted in a high RET quenching efficiency, leading to a low background signal and high sensitivity. Subsequently, under alkaline conditions, the blue colored MB was chemically reduced to colorless methylene white (MW) within minutes of the addition of Glu, accompanied by the disappearance of absorbance centred at about 665 nm. This redox process suppressed the quenching capacity of MB, thereby restoring the ECL response of the luminophore. Therefore, the "turn-on" ECL sensor combined the RET strategy and redox reaction, achieving rapid and sensitive detection of Glu. The proposed ECL-RET sensor performed well for Glu detection with a detection limit of 8.1 nM and a wide linear range from 10 nM to 100 mM, along with acceptable stability and reproducibility. Furthermore, the facile ECL sensor, which integrates RET with redox reaction, was successfully applied to real samples, demonstrating its potential promise in clinical diagnosis and disease monitoring.