Intramolecular Enhancement of a Zirconium-Based Metal–Organic Framework for Coordination-Induced Electrochemiluminescence Bleomycin Analysis

Abstract

It is significantly vital to develop a convenient assay method in clinical treatment due to an atypically low abundance (∼5 μM) of bleomycin (BLM) used in clinics. Herein, an electrochemiluminescence (ECL) biosensor using a zirconium-based metal−organic frameworks (Zr-MOFs) as an intramolecular coordination-induced electrochemiluminescence (CIECL) emitter was proposed for sensitive detection of BLM. Zr-MOFs were synthesized using Zr(IV) as metal ions and 4,4′,4″-nitrilotribenzoic acid (H 3 NTB) as ligands for the first time. The H 3 NTB ligand not only acts as coordination units bonding with Zr(IV) but functions as a coreactant to enhance ECL efficiency rooted in its tertiary nitrogen atoms. Specifically, a long guanine-rich (G-rich) single-stranded DNA (ssDNA) was released by the target-BLMcontrolled DNA machine that could perform π−π stacking with another G-quadruplex, ssDNArhodamine B (S-RB), by shearing DNA's fixed sites 5′-GC-3′ and the auxiliary role of exonuclease III (Exo III). Finally, due to the quenching effect of rhodamine B, a negative correlation trend was obtained between ECL intensity and BLM concentration in the range from 5.0 nM to 50 μM and the limit of detection was 0.50 nM. We believe that it is a promising approach to guide the preparation of CIECL-based functional materials and establishment of analytical methods.

Dual-Ligand Europium-Organic Gels as a Highly Efficient Anodic Annihilation Electrochemiluminescence Emitter for Ultrasensitive Detection of MicroRNA

“…As can be seen from Figure D, the fluorescence lifetime decay curves of Eu 3+ , Eu-S-MOGs, and Eu-D-MOGs conformed to monoexponential functions, in which I 0 , t , and τ were the correlation coefficient, time, and lifetime, respectively (Figure S1). After the fitting calculation, it could be concluded that the fluorescence lifetime of Eu 3+ , Eu-S-MOGs, and Eu-D-MOGs increased in turn. , The fluorescence lifetime of Eu-D-MOGs (5.50 ms) lasted about 1.5 times longer than that of Eu-S-MOGs (3.63 ms); this indicated that the introduction of the second ligand BTC would reduce the coordination between Eu 3+ and H 2 O to further improve the ECL signal. As depicted in Figure A, the ECL maximum emission wavelength of Eu-D-MOGs was located at 614 nm, and it did not change distinctly compared with the FL maximum emission wavelength of Eu-D-MOGs located at 609 nm (Figure B).…”

Supramolecular Anchored Copper Nanoclusters for a Multipath Electrochemiluminescence Probe

“…Therefore, we refer to it as ligand-triggered ECL. The mechanism of ligand-triggered ECL was explained as follows: first, H 2 NC 2 H 4 –NH 2 was electrochemically oxidized to H 2 NC 2 H 4 –NH 2 •+ on the electrode surface (eq ). At the same time, some CET-Cu NCs were oxidized to CET-Cu NCs •+ on the electrode surface (eq ).…”

Porous Complex-Mediated Dual Emission of Porphyrins for the Electrochemiluminescence Bioassay

“…As an ingenious combination of electrochemistry and chemiluminescence, electrochemiluminescence (ECL) is high-profile for its near-zero background and high controllability and sensitivity, resulting in its widespread application in biosensing and optoelectronic devices. − High-efficient luminophors are inarguably the most critical part in the ECL assay. Among the reported electrochemiluminophors, porphyrins have become concerned ECL emitters due to their excellent physicochemical and electronic properties. − Nevertheless, porphyrins are prone to undergo aggregation-caused quenching (ACQ) of light emissions in aqueous solutions, thus leading to unsatisfactory ECL emission, which hampered their further application. − …”