A mixed-organic ligands Ru(bpy)32+@Zn mMOFs-NH2 nanoreactors integrated co-reaction accelerator and morphologic regulator for the electrochemiluminescence detection of ATP

Abstract

The functionalized architecture within the nanoreactor could dramatically change the electron transport and reaction efficiency of ECL during electrochemical processes. Here, we've devised a novel mixed-ligand strategy that combines co-reaction accelerator and morphologic regulator onto the same metal node. This innovative approach effectively addressed the critical issue that some co-reactants cannot be covalently linked due to their special states, while enhancing the stability and electroactivity of MOFs nanoreactors. Ru(bpy)₃²⁺ was in-situ encapsulated within Zn mMOFs-NH₂ nanocages in which the 2-aminoterephthalic acid (NH₂-BDC) ligand functioned as an effective co-reaction accelerator. While S₂O₈²⁻ underwent electron exchange on the surface of GCE to form SO₄^•−, Zn mMOFs-NH₂ was electrochemically oxidized to Zn mMOFs-NH^•, which could significantly catalyze S₂O₈²⁻ to form SO₄^•−. This greatly increased the local concentration of SO₄^•− in the vicinity of Ru(bpy)₃²⁺, thus achieving self-enhancing ECL. At the same time, 1,4-benzenedicarboxylic acid (BDC) ligands were used as morphologic regulator, yielding ultra-thin MOFs nanosheets that significantly boosted the loading capacity for Ru(bpy)₃²⁺ and enhanced electrical conductivity. The luminous efficiency of Ru(bpy)₃²⁺ is further enhanced by this synergy. A highly sensitive ECL biosensor was crafted for the detection of ATP. Optimal conditions allowed a robust linear correlation between the ECL intensity and the logarithm of ATP concentration, enabling a sensitive detection limit down to 1.18 nM. Our findings underscore the exceptional self-enhanced ECL properties of the devised Ru(bpy)₃²⁺@Zn mMOFs-NH₂ nanoreactors, presenting a novel and promising platform for biomolecular analysis.