MnO₂ Nanosheet/Polydopamine Double-Quenching Ru(bpy)₃²⁺@TMU-3 Electrochemiluminescence for Ultrasensitive Immunosensing of Alpha-Fetoprotein

Abstract

In this work, we propose a novel double-quenching electrochemical luminescence (ECL) strategy; this strategy is based on the double-quenching effect of Ru­(bpy)3 2+-functionalized three-dimensional (3D) metal–organic framework (MOF) by MnO2/PDA. An ECL immunosensor for ultrasensitive detection of alpha-fetoprotein (AFP) has been designed. TMU-3 with a rich mesoporous structure can be used to encapsulate Ru­(bpy)3 2+, which can effectively reduce the leakage of Ru­(bpy)3 2+. Moreover, the ultraviolet–visible (UV–vis) absorption spectrum of the lamellar MnO2/PDA nanomaterials with a nanometer scale of about 1 μm overlaps with the ECL emission spectrum of the porous bamboo leaf-like Ru­(bpy)3 2+@TMU-3 with a nanometer scale of about 1 μm. Thus, an ECL resonance energy transfer (ECL-RET) mechanism between Ru­(bpy)3 2+@TMU-3 (donor) and MnO2/PDA (recipient) is formed. In this way, an ECL immunosensor with a dual-quenching strategy for ECL signal is developed. In order to test the practicability of this method in clinical analysis, the detection target marker AFP content ranged from 0.01 pg/mL to 5 ng/mL and the detection limit was set to 10.7 fg/mL. In summary, this work demonstrates the detection and application of a signal-quenched ECL immunosensor and ECL immunoassay based on a luminescence-functionalized MOF system for biomarker detection. It indicates a great prospect in the analysis of other biomarkers and clinical analysis.

Surface Oxygen Vacancy-Rich Co3O4 Nanowires as an Effective Catalyst of Luminol–H2O2 Chemiluminescence for Sensitive Immunoassay

“…Then, Vo-Co 3 O 4 @PDA conjugated the secondary antibody (Ab 2 ) via catechol group of the PDA layer, − achieving Vo-Co 3 O 4 @PDA/Ab 2 probe (Scheme A). Dynamic light scattering was applied to characterize the Vo-Co 3 O 4 @PDA/Ab 2 probe.…”

A quenching electrochemiluminescence energy resonance transfer system based on CdS and COFs for the ultrasensitive detection of CA242

“…For the purpose of maximizing the protection of the biomolecular activity while obtaining a strong ECL signal, the optimal pH of PBS was 7.4. 36,37 Since the H 2 O 2 concentration in PBS has an important effect on the ECL emission signal of the CdS NCs, it was necessary to evaluate the optimal H 2 O 2 concentration by experiments. The immunosensor with 1 U mL À1 CA242 was assembled for testing in PBS (0.1 M, pH = 7.4) with different concentrations of H 2 O 2 (20, 30, 40, 50 and 60 mM).…”

Framework-Enhanced Electrochemiluminescence in Biosensing

“…Zhao et al synthesized bimetallic NiZn MOF nanosheets to amplify cathodic luminol ECL through the synergistic effect of the bimetallic catalyst in AFP immunodetection [73]. Li et al designed a signal-off ECL biosensor for AFP detection by utilizing the MnO 2 nanosheet/polydopamine dual-quenching effect towards a Ru(bpy) 3 2+functionalized MOF [74].…”