Dumbbell Plate‐Shaped AIEgen‐Based Luminescent MOF with High Quantum Yield as Self‐Enhanced ECL Tags: Mechanism Insights and Biosensing Application

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2022-04, Vol.18 (13), p.e2106567-n/a
• Main Authors: Li, Jingshuai, Jia, Hongying, Ren, Xiang, Li, Yuyang, Liu, Lei, Feng, Ruiqing, Ma, Hongmin, Wei, Qin
• Format: Article
• Language: English
• Subjects: AIEgens; Biosensing Techniques; Electrochemical Techniques; Electrochemiluminescence; Emission spectra; Emitters; Energy transfer; Immunoassay; Limit of Detection; Luminescent Measurements; luminescent metal–organic frameworks (MOFs); Luminous efficacy; Metal-Organic Frameworks; Nanotechnology; neuron‐specific enolase; Photoluminescence; Polyethyleneimine; self‐enhanced signal probes; Silicon Dioxide; Tags; Zirconium
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202106567

It is widely known that high‐performance electrochemiluminescence (ECL) emitters play a crucial part in improving the detection sensitivity of the ECL strategy. Through the combination of aggregation‐induced emission luminogens (AIEgens), 1,1,2,2‐tetra(4‐carboxylbiphenyl)ethylene (H4TCBPE) with Zr(IV) cations, a dumbbell plate‐shaped metal−organic framework (MOF) with high luminous efficiency is synthesized as ECL tags. The resultant MOF exhibits stronger ECL activity than those of H4TCBPE monomers and aggregates. Herein, this phenomenon is defined as the coordination‐triggered electrochemiluminescence (CT‐ECL) enhancement effect. Furthermore, the nearly matched ECL and photoluminescence (PL) spectra imply the bandgap emission mechanism. Remarkably, polyethyleneimine (PEI) as the coreactant is covalently connected with MOF to form the uniquely self‐enhanced ECL complex of Zr‐TCBPE‐PEI, where the robust ECL signal is captured owing to the intramolecular‐like coreaction acceleration. Based on the resonance energy transfer (RET) behavior, the AuPd@SiO2 composite is designed as the high‐efficiency quencher. In this manner, an innovative and ultrasensitive ECL sensor is constructed for neuron‐specific enolase (NSE) detection through sandwich‐type immunoreaction, with the detection limit down to 52 fg ml−1. The present study has gone some way toward designing MOF‐based self‐luminescent ECL materials, thus paving a new avenue to expand the late‐model ECL emitters for immunoassay. A dumbbell plate‐like zirconium metal–organic framework (Zr‐TCBPE‐MOF) with high ECL efficiency is synthesized as an emitter in an electrochemiluminescence (ECL) immunoassay. The resultant MOF exhibits coordination‐triggered ECL enhancement compared with its ligand (H4TCBPE) in free or aggregate states. The well‐matched ECL and photoluminescence spectra demonstrate the bandgap emission mechanism.