Boosting Aggregation-Induced Electro-Chemiluminescence in TPE-Based Macrocycles via Supramolecular Confinement: A Host−Guest Recognition Platform for 3-Nitrotyrosine Biosensing

Abstract

Although aggregation-induced electrochemiluminescence (AIECL) holds significant promise for signal amplification, its practical advancement is impeded by the intrinsically low ECL efficiency of conventional AIEgens and the stochastic nature of aggregate formation. Herein, we devise a dual supramolecular-molecular engineering strategy to synthesize tetraphenylethylene (TPE)-based covalent organic macrocycles (MCs) via Menschutkin reaction-mediated macrocyclization. By tuning the electronic structure of the bridging ligands, we achieved precise modulation of both the aggregation topology and excited-state dynamics of the TPE core. The resulting MCs exhibited exceptional ECL performance, achieving a relative efficiency of 2237% compared with the benchmark [Ru(bpy)3]2+ and showing a significant emission redshift of 94−167 nm relative to the uncyclized precursor. Density functional theory (DFT) calculations revealed that macrocyclization narrows the HOMO−LUMO gap, thereby facilitating radiative transitions. Furthermore, leveraging the well-defined cavity of the MCs, we constructed a high-performance ECL biosensor for 3-nitrotyrosine (3-NT) based on specific host−guest recognition. This sensor achieved an ultra-wide linear range (0.01−1000 μM) and a low detection limit of 1.3 nM. Collectively, this work offers a systematic strategy to overcome the efficiency and morphological bottlenecks of AIECL luminogens, paving the way for the rational design of advanced emitters in next-generation biosensing platforms.