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

Abstract

low background interference, and easy operation. [4][5][6][7] Nowadays, ECL with these favorable benefits has become one powerful analytical technique applied in biomarkers, food safety, and environmental pollutants analyses. [8][9][10][11] As it is well known, the high sensitivity for the ECLbased immunoassays was mainly attributable to the excellent luminophores. [12] At present, most of the reported methods used nanomaterials like multi-porous nanoparticles (NPs) [13,14] or metal−organic frameworks (MOFs) [15][16][17] as carriers to immobilize the typical ECL emitters, including luminol, tris-bipyridyl ruthenium (Ru(bpy) 3 2+), and their derivatives. [1] In particular, MOFs have received intense attention in ECL analysis because of their high poriness, easy functionalization, and ultrahigh surface area. [18][19][20] Nonetheless, these nanomaterials based strategies for luminophores immobilization by postmodification or encapsulation, still exist some shortcomings when used in aqueous phase. For instance, the poor stability of MOFs in water would result in leakage of ECL chromophores, and the large steric hindrance of organic luminophores limited the loading capacity to some extent, which both abridged their in-depth application in ECL bioassays. Thus, without the trivial post-synthetic steps, it seems an ideal way to design innovative ECL luminophores based MOFs that emitted light by themselves.Currently, some groups have reported that the Ru(bpy) 3 2+ derivatives, could be employed as organic ligands to fabricate MOFs with self-luminescent properties. [21,22] To some extent, the aggregation-caused quenching (ACQ) effect [23,24] was unavoidable due to the π-π stacking of the aggregated luminescent centrosome. Fortunately, aggregation-induced emission (AIE), which was proposed by Tang and co-workers in 2001, [25] paved a new avenue to resolve this problem. So far, a variety of AIE luminogens (AIEgens)-based nanomaterials have been widely applied in the fields of solid-state optoelectronic devices, [26,27] fluorescence imaging, [28] and biosensors, [29][30][31] because the AIEgens displayed strong emission in aggregated state but almost nonemissive in diluted solution with molecule-free state. [32] Inis 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 (H 4 TCBPE) 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 H 4 TCBPE 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 ...

Dual-Mechanism Quenching of Electrochemiluminescence Immunosensor Based on a Novel ECL Emitter Polyoxomolybdate-Zirconia for 17β-Estradiol Detection

“…The flat-band potential ( E fb ) of POM-ZrO 2 was reckoned with −0.82 V versus SCE (−0.58 V vs NHE) based on the X-intercept of the tangent line (Figure S8C). The conduction band (CB) level ( E cb ), about 0.2 V lower than E fb , was about −0.78 V relative to NHE. Thus, the valence band (VB) potential ( E vb ) could be calculated as 2.25 V relative to NHE based on the formula E g = E vb – E cb .…”

“…First, the CV of the modified electrode with POM-ZrO 2 was measured at a series of different scanning rates from 0.02 to 0.20 V/s for calculating the electrochemically active area of the electrode. , The complete calculation process can be seen in the Supporting Information. The electrochemical active area was calculated to be 0.1648 cm 2 based on the formula, while the actual area of bare GCE was 0.1256 cm 2 (Φ = 4 mm).…”

Electrochemiluminescent sensor based on an aggregation-induced emission probe for bioanalytical detection

“…5B). 81 As a typical tumor marker, the detection of cytokeratin 19 fragment 21-1 (CYFRA 21-1) is of great significance. Wei synthesized an Ir( ppy) 3 @apoFt bioconjugate with AIECL characteristics as a probe.…”

Progress and Prospects of Electrochemiluminescence Biosensors Based on Porous Nanomaterials

“…In addition, the authors combined Zr-TCBPE-MOF with polyethyleneimine (PEI) to prepare a unique self-reinforced Zr-TCBPE-PEI electroluminescent complex, which could effectively avoid the bio-toxicity of the co-reactant and exhibit a more dramatic ECL response. The prepared ECL sensor showed good correlation in the range of 0.0001–10 ng/mL and the lower LOD was 52 fg/mL, providing an effective way for the early and sensitive detection of small cell lung cancer [ 64 ].…”

“… Schematic illustration for the synthesis of ( A ) Zr-TCBPE-PEI-Ag NPs substrate and ( B ) Ab 2 -AuPd@SiO 2 bioconjugate, and ( C ) the fabrication process of the proposed ECL immunosensor with possible ECL-enhancing effects and luminescence mechanism [ 64 ]. Copyright © 2022, John Wiley and Sons.…”