Hydrogen Bond Organic Frameworks as Radical Reactors for Enhancement in ECL Efficiency and Their Ultrasensitive Biosensing

Nowadays, electrochemiluminescence (ECL) effi-ciency of an organic emitter is closely related with its potential applications in food safety and environmental monitoring fields. In this work, 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine (TATB) was self-assembled to form hydrogen bond organic frameworks (HOFs), which worked as ideal reactors to generate highly active oxygen-containing radicals, followed by linking with isoluminol (ILu) via amide bond (termed ILu-HOFs). After covalent assembly with aminated indium-tin oxide electrode (labeled NH2-ITO), the ECL efficiency of the ILu-HOFs NH2-ITO showed about a 23.4 -time increase over that of ILu itself in the presence of H2O2. Meanwhile, the enhanced ECL mechanism was mainly studied by electron paramagnetic resonance, theoretical calculation, and electrochemistry. On the above foundation, an aptamer sandwich ECL biosensor was constructed for detecting isocarbophos (ICP) via in situ elimination of H2O2 with catalase-linked palladium nanocubes (CAT-Pd NCs). The as-built sensor showed a broad linear range (1 pM to 100 nM) and a low limit of detection (LOD) down to 0.4 pM, coupled with efficient assays of ICP in lake water and cucumber juice samples. This strategy provides an effective way for the synthesis of advanced ECL emitter, coupled by showing promising applications in environmental and food analysis.

Automated summary

In this study, HOFs were formed by self-assembly of TATB and linked with ILu via amide bond to improve the ECL efficiency. The ILu-HOFs NH2-ITO showed a 23.4-fold increase in ECL efficiency compared to ILu alone. A sandwich ECL biosensor was then constructed for the detection of ICP, achieving a broad linear range and low LOD, and successfully detecting ICP in environmental samples.