Intrareticular Charge Transfer Triggered Self-Electrochemiluminescence of Zirconium-Based Metal-Organic Framework Nanoparticles for Potential-Resolved Multiplex Immunoassays with Isolated Coreactants

In this work, a potential-resolved electrochemiluminescence(ECL)multiplex immunoassay (MIA) was developed using zirconium-based metal-organicframework (MOF) nanoparticles with intense self-ECL as an anodic ECLtag and CdTe nanocrystals (NCs) as a cathodic ECL tag. ECL luminophore5,5 & PRIME;-(anthracene-9,10-diyl)diisophthalic acid (H(4)ADIP) and coreactant hexamethylenetetramine (HMT) bound to zirconiumnodes in the MOF, giving Zr-ADIP-HMT nanoparticles. Benefiting fromthe intrareticular charge transfer (ICT) between the oxidized ligandsof H(4)ADIP and HMT via hydrogen bonds, the intense self-ECLfrom Zr-ADIP-HMT was applied to the potential-resolved ECL MIA withoutan exogenous anodic coreactant, which can eliminate detrimental effectsof multiplex coreactants and anodic ECL emission from CdTe NCs. TheICT within Zr-ADIP-HMT nanoparticles could shorten the electron transportpath and reduce the complexity of radical intermediate transport.The ECL intensity from Zr-ADIP-HMT was 18.6-fold that from the mixtureof H(4)ADIP and HMT. In potential-resolved ECL MIA, two lungcancer biomarkers, carcinoembryonic antigen and neuron-specific enolase,were adopted as model analytes, with detection limits of 18 and 5.3fg & BULL;mL(-1), respectively. The dual-ligand Zr-ADIP-HMTnanoparticles provide a proof of concept using ICT-based self-ECLluminophores for potential-resolved ECL MIAs with isolated coreactants.

Automated summary

In this study, a potential-resolved electrochemiluminescence multiplex immunoassay was developed using zirconium-based metal-organic framework nanoparticles and CdTe nanocrystals as ECL tags. The intense self-ECL from Zr-ADIP-HMT nanoparticles was applied to the MIA without an exogenous anodic coreactant, enabling the detection of lung cancer biomarkers with low detection limits. This method eliminates interference from multiplex coreactants and enhances the ECL intensity.