Self-luminescent dual-ligand metal-organic framework based electrochemiluminescence probes for organophosphorus pesticides determination

In this study, a signal amplification strategy was developed, which tris (2, 2′-bipyridyl) ruthenium (II) (Ru(bpy)₃²⁺) was incorporated as a guest molecule into the preparation system of lanthanide-based metal-organic framework (MOF). This strategy relied on strong electrostatic interactions and coordination competition to influence the growth process of the MOF, resulting in the firm immobilization of Ru(bpy)₃²⁺ within the MOF structure. The spatial confinement effect of the MOF effectively improved the efficiency of electron transfer in the electrochemiluminescence (ECL) reaction. The constructed ECL aptasensor using this MOF exhibited excellent performance, with limits of detection (LODs) for four organophosphorus pesticides (OPs), phorate, profenofos, isocarbophos and omethoate, as low as 0.0482 ng/mL, 0.0093 ng/mL, 0.0085 ng/mL, and 0.0893 ng/mL, respectively. This work has paved the way for a clever strategy of immobilizing Ru(bpy)₃²⁺ molecules and amplifying signals, expanding the application of dual-ligand MOF, which provides valuable insights for future biosensor design.