Issue 3, 2024

Redox-mediated electrochemiluminescence enhancement for bead-based immunoassay


Electrochemiluminescence (ECL) is a highly sensitive mode of detection utilised in commercialised bead-based immunoassays. Recently, the introduction of a freely diffusing water-soluble Ir(III) complex was demonstrated to enhance the ECL emission of [Ru(bpy)3]2+ labels anchored to microbeads, but a comprehensive investigation of the proposed ‘redox-mediated’ mechanism was not carried out. In this work, we select three different water-soluble Ir(III) complexes by virtue of their photophysical and electrochemical properties in comparison with those of the [Ru(bpy)3]2+ luminophore and the TPrA co-reactant. A systematic investigation of the influence of each Ir(III) complex on the emission of the Ru(II) labels on single beads by ECL microscopy revealed that the heterogeneous ECL can be finely tuned and either enhanced up to 107% or lowered by 75%. The variation of the [Ru(bpy)3]2+ ECL emission was correlated to the properties of each Ir(III)-based mediator, which enabled us to decipher the mechanism of interaction and define guidelines for the future design of novel Ir(III) complexes to further enhance the ECL emission of bead-based immunoassays. Ultimately, we showcase the potential of this technology for practical sample analysis in commercial instruments by assessing the enhancement of the collective ECL intensity from a bead-based system.

Graphical abstract: Redox-mediated electrochemiluminescence enhancement for bead-based immunoassay

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Article information

Article type
Edge Article
27 Nov 2023
08 Dec 2023
First published
19 Dec 2023
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2024,15, 1150-1158

Redox-mediated electrochemiluminescence enhancement for bead-based immunoassay

A. Fracassa, C. I. Santo, E. Kerr, S. Knežević, D. J. Hayne, P. S. Francis, F. Kanoufi, N. Sojic, F. Paolucci and G. Valenti, Chem. Sci., 2024, 15, 1150 DOI: 10.1039/D3SC06357G

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