Hydrogen Bond Organic Frameworks as a Novel Electrochemiluminescence Luminophore: Simple Synthesis and Ultrasensitive Biosensing

Abstract

Nowadays, continuous efforts have been devoted to searching highly efficient electrochemiluminescence (ECL) emitters for applications in clinical diagnosis and food safety. In this work, triazinyl-based hydrogen bond organic frameworks (Tr-HOFs) were synthesized by N···H hydrogen bond self-assembly aggregation, where 6,6′-(1,4-phenylene)­bis­(1,3,5-triazine-2,4-diamine) (phenyDAT) was prepared via the cyclization reaction and behaved as a novel ligand. Impressively, the resulting Tr-HOFs showed strong ECL responses with highly enhanced ECL efficiency (21.3%) relative to the Ru­(bpy)3 2+ standard, while phenyDAT hardly showed any ECL emission in aqueous phase. The Tr-HOFs innovatively worked as a new ECL luminophore to construct a label-free biosensor for assay of kanamycin (Kana). Specifically, the ECL response greatly weakened upon assembly of captured DNA with ferrocene (cDNA-Fc) onto the Tr-HOFs-modified electrode, while the ECL signals were adversely recovered by releasing linked DNA (L-DNA) from double-stranded DNA (dsDNA, hybridization of aptamer DNA (aptDNA) with L-DNA) due to the specific recognition of Kana with the aptDNA combined by the linkage of L-DNA and cDNA-Fc on the electrode. The as-built sensor showed a broadened linear range (1 nM–10 μM) and a limit of detection (LOD) down to 0.28 nM, which also displayed satisfactory results in the analysis of Kana in the milk and diluted human serum samples. This work offers a novel pathway to design an ECL emitter with organic molecules, holding great promise in biomedical analysis and food detection.

Intrareticular electron coupling pathway driven electrochemiluminescence in hydrogen-bonded organic frameworks

“…Interestingly, the ECL efficiency of HOF-101/K 2 S 2 O 8 was as high as 64.7% compared with that of the 0.1 mM Ru(bpy) 3 2+ /TPrA (20 mM) system (Fig. S32, ESI†), which is superior to 5.22% of the conductive COF/K 2 S 2 O 8 system, 51 57.10% of donor–acceptor COFs, 52 21.3% of triazinyl HOF, 29 and 15.9% of the Zn-tetracarboxylate MOF/K 2 S 2 O 8 system (Table S7, ESI†). 53…”

“…Typically, a label free ECL biosensor for kanamycin assay was constructed based on a triazinyl HOF self-assembled by NÁ Á ÁHbond aggregation with a relative ECL efficiency of 21.3%. 29 Moreover, the highly crystalline HOFs have the advantages of mild synthesis conditions, 30 strong intermolecular interactions, 31 proton conduction, 32 and high fluorescence quantum yield 33 to promote efficient optoelectronic transduction for producing ECL. As a comparison, the heavy metals in metal-organic frameworks (MOFs) tend to quench the emission, 34,35 and most COFs connected by imine bonds have poor conductivity and it is easy to rotate them in the excited state to cause non-radiative transition, [36][37][38] which blocks their application in ECL.…”

Heterometallic nanomaterials: activity modulation, sensing, imaging and therapy

“…Beyond the above, ECL is a potential initiated form of chemiluminescence, and offers opportunity for an optical readout in catalysis, sensing and analysis, where luminophores are oxidized or reduced at the electrode surface and yield emissive excited-state species. 198–200 For instance, ECL microscopy was applied to characterize electro–catalytic activity of Au–Pt JNPs (Fig. 5G–I).…”

An Ultrasensitive Picric Acid Sensor Based on a Robust 3D Hydrogen-Bonded Organic Framework

“…Hydrogen-bonded organic frameworks (HOFs), self-assembled by discrete organic molecules via intermolecular hydrogen-bonding interactions, can be further reinforced via weak connections, such as π-π, van der Waals, and/or C-H-π interactions, which has attracted much attention in recent years [ 1 , 2 , 3 , 4 , 5 , 6 ]. Attributed with some distinct advantages such as orderly pore structures, easy synthesis, facile renewability and recyclability, this kind of crystal materials is investigated in the fields of gas storage and separation [ 7 , 8 , 9 ], chemical sensing [ 10 , 11 , 12 , 13 , 14 , 15 , 16 ], biomedicine [ 17 , 18 ], catalysis [ 19 , 20 , 21 ], proton conduction [ 22 , 23 ], and so on [ 24 , 25 , 26 ]. To date, although several organic building units (OBUs) with carboxylic acid synthons have been applied to synthesize HOF, most building units still focus on tri-, tetra-, and hexa-carboxylic acid-building units [ 27 , 28 , 29 ].…”