Coreaction Accelerator Research Articles

Cu Single-Atom Nanozyme-Mediated Electrochemiluminescence Biosensor for Highly Sensitive Detection of MicroRNA-622.

MicroRNA (miRNA) detection is a critical aspect of disease diagnosis, and recent studies indicate that miRNA-622 could be a potential target for lung cancer. Herein, Cu single atoms were anchored on graphitic carbon nitride (Cu SAs@CN) as a coreaction accelerator applied in luminol-H2O2 system, thereby establishing an efficient and sensitive electrochemiluminescence (ECL) biosensor for miRNA-622 detection. Cu SAs@CN was explored to possess excellent enzyme-like activities that promote the generation of abundant reactive oxygen species, which amplified ECL emission. Meanwhile, in order to improve the accuracy and sensitivity for miRNA-622 detection, the highly specific trans-cleavage ability of CRISPR/Cas12a was combined with a catalytic hairpin assembly strategy. Therefore, an ECL biosensor for miRNA-622 detection was systematically constructed as a proof of concept, achieving an ultralow limit of detection of 1.09 fM, and the feasibility was demonstrated in human serum samples. The findings of this research provide a promising strategy to enhance the ECL response using versatile single-atom catalysts, thus advancing the development of ECL biosensing applications.

Ternary electrochemiluminescence biosensor based on Ce2Sn2O7@MSN luminophore and Au@NiO-CeO2 as a co-reaction accelerator for the detection of prostate specific antigen

A ternary ECL system was constructed with Ce2Sn2O7@MSN composite as luminophore, potassium persulfate as co-reactant and Au@NiO-CeO2 as co-reaction accelerator to realize ultra-sensitive biosensing detection of prostate specific antigen (PSA). The abundant oxygen vacancies in Ce2Sn2O7 endow it with powerful electrochemical redox ability, accelerate energy transfer, and ensure Ce2Sn2O7 excellent electrochemical luminescence performance as a luminophore. Furthermore, to optimize the luminescence energy, enhance stability, and reduce the background signal to improve its signal-to-noise ratio, a highly selective Ce2Sn2O7@MSN biological probe was obtained by coating cerium stannate (Ce2Sn2O7) with mesoporous silica nanospheres (MSN). Au@NiO-CeO2 with a large specific surface area and high oxygen vacancy activity was synthesized as the co-reaction accelerator, which promoted the generation of SO4•− through the rapid reversible oxidation and reduction of Ce4+/Ce3+, thereby the ECL signal amplified effectively. Under optimal conditions, the linear detection range of PSA spans from 100fg mL−1 to 100 ng mL−1, with a remarkable lowest detection limit of 0.037pg mL−1, showcasing significant application potential. This study provides a valuable reference for pyrochlore to be used as luminophore in the detection of various biomarkers by ECL biosensing.

Novel pore confinement enhanced europium functionalized porphyrin covalent organic framework electrochemiluminescence microreactor and its application to microRNA-21 detection

Here, an electrochemiluminescence (ECL) microreactor lanthanide europium functionalized porphyrin covalent organic framework (Eu@TAPP-COF) was developed through Schiff base condensation between 1,3,5-benzenetricarboxaldehyde (BTCA) and 5,10,15,20-tetrakis(4-aminophenyl)-porphyrin (TAPP) with the coordination reaction between the COF skeleton and Eu3+. Compared with O2/S2O82− and TAPP-COF/S2O82− systems, the ECL intensity of Eu@TAPP-COF/S2O82− is significantly enhanced by 5.1 and 1.3 times, respectively. It can be attributed to the positively charged micropore structure of the Eu@TAPP-COF, providing a relatively independent reaction environment for the electrochemical oxidation of S2O82− and the intermediate SO4•−, moreover shortening the distance among the ECL luminophore TAPP, the co-reaction accelerator Eu3+, and the co-reaction reagent S2O82−. Based on this novel emitter, an ECL biosensor was developed for microRNA-21 detection via the signal amplification strategy of catalytic hairpin assembly (CHA). The as-prepared biosensor displayed high sensitivity for target with a dynamic linear response range from 100 aM to 100 pM, and a lower detection limit of 21 aM (S/N = 3). This work provides an idea for the sensing application of weak luminophore and a simple, effective and accurate detection platform for tumor markers.

A signal-on electrochemiluminescence (ECL) sensor based on luminol@carbon nanotubes and CdTe-ZnS@hydroxyapatite for the detection of paclitaxel

A signal-on solid-state electrochemiluminescence (ECL) sensor based on luminol@carbon nanotubes (luminol@CNTs) and CdTe-ZnS@hydroxyapatite (CdTe-ZnS@HAP) was constructed for the detection of paclitaxel (PTX). In this sensing platform, luminol was used as the main luminophore and CdTe-ZnS was used as a co-reaction accelerator. CNTs and HAP were acted as carriers to adsorb more luminophores and co-reaction promoters. In addition, due to the enhanced effect of PTX on the ECL intensity of the luminol-O2 system, PTX was introduced as the final detection target. Under the optimal experimental conditions, the ECL intensity change values (ΔI) of the sensor showed a good linear relationship with the logarithm of PTX concentration in the range of 3 × 10-12 − 3 × 10-7 molL-1, and the limit of detection was 1 × 10-12 mol L-1(S/N = 3). This method was successfully applied to the determination of trace PTX concentration in serum.

Highly Electroactive Co2+-Based Metal-Organic Frameworks as an Efficient Coreaction Accelerator for Amplifying Near-Infrared Electrochemiluminescence of Gold Nanoclusters in Biomarkers Immunoassay.

Metal nanoclusters (NCs) as a new kind of luminophore have acquired sufficient interest, but their widespread application is restricted on account of their relatively low electrochemiluminescence (ECL) efficiency. Then, aqueous metal NCs with high ECL efficiency were strongly anticipated, especially for the ultrasensitive analysis of biomarkers. Herein, a near-infrared (NIR) ECL biosensing strategy for the test of neuron-specific enolase (NSE) was proposed by utilizing N-acetyl-l-cysteine (NAC)- and cysteamine (Cys)-stabilized gold NCs (NAC/Cys-AuNCs) as ECL emitters with the NIR ECL emission around 860 nm and a metal-organic framework/palladium nanocubes (ZIF-67/PdNCs) hybrid as the coreaction accelerator through their admirable electrocatalytic activity. The NIR emission would reduce photochemical injury to the samples and even realize nondestructive analysis with highly strong susceptibility and suitability. Furthermore, the utilization of ZIF-67/PdNCs could improve the ECL response of NAC/Cys-AuNCs by facilitating the oxidation of the coreactant triethylamine (TEA), leading to the production of a larger quantity of reducing intermediate radical TEA•+. Consequently, NAC/Cys-AuNCs with ZIF-67/PdNCs displayed 2.7 fold enhanced ECL emission compared with the single NAC/Cys-AuNCs using TEA as the coreactant. In addition, HWRGWVC (HWR), a heptapeptide, was introduced to immobilize antibodies for the specially binding Fc fragment of the antibodies, which improved the binding efficiency and sensitivity. As a result, a "signal-on" immunosensor for NSE analysis was obtained with an extensive linear range of 0.1 to 5 ng/mL and a low limit of detection (0.033 fg/mL) (S/N = 3). This study provides a wonderful method for the development of an efficient nondestructive immunoassay.

VS4 Nanodendrites with Narrow Bandgaps in Activating Dissolved Oxygen for Boosted Chemiluminescence and Hemin Detection by Unexpected Quenching.

Chemiluminescence (CL)-based analytical methods utilize luminophores that need to be activated with an oxidizing agent to trigger CL emission. Despite its susceptibility to decomposition when exposed to external light or trace metals, hydrogen peroxide (H2O2) has been widely used to develop chemiluminescent methods due to the limited number of suitable alternatives for activating chemiluminescent luminophores. Also, analytical methods based on the well-known luminol/H2O2 CL system have low sensitivity. Dissolved oxygen (DO) is a naturally abundant and environmentally benign alternative oxidant for luminol and other CL luminophores. However, DO alone is inactive and needs an efficient catalyst or a coreaction accelerator for its activation. Because of the narrow bandgap of VS4 (ca. 1.12 eV), it can facilitate fast electron-transfer kinetics with an acceptor molecule such as DO. Here, we introduce vanadium tetrasulfide (VS4) to boost CL for the first time. Under the optimized conditions, VS4 nanodendrite catalyzes the generation of reactive oxygen species by activating DO which subsequently reacts with luminol to generate intense CL. It enhances the CL intensity of luminol/DO by about 10,000 times. Surprisingly, hemin remarkably quenches the generated CL of luminol/DO/VS4 nanodendrites, which is completely opposite to its typical enhancement of luminol CL. Based on the remarkable concentration-dependent quenching of the luminol/DO/VS4 nanodendrite CL by hemin, we have developed a sensitive CL method that can selectively detect hemin in the linear concentration range of 1-250 nM and achieved a limit of detection of 0.11 nM. The practical utility of the developed method was demonstrated by the determination of hemin in a pharmaceutical drug for the treatment of acute intermittent porphyria and in human serum. This study demonstrates that VS4 holds great promise in analytical method development.

Novel Nucleic Acid-Assisted Ion-Responsive ECL Biosensor Based on Hollow AuAg Nanoboxes with Excellent SPR and Effective Coreaction Acceleration.

Novel hollow AuAg nanoboxes (AuAg NBs) were designed for an innovative electrochemiluminescence (ECL) sensor to ultrasensitively detect Pb2+ and Hg2+ with the aid of DNAzyme and "thymine-Hg2+-thymine" ("T-Hg2+-T") structure. AuAg NBs are employed as an excellent surface plasma resonance (SPR) source, as well as an effective coreaction accelerator for the CoNi NFs/S2O82- system to greatly improve ECL performance. To detect Pb2+, the DNAzyme catalyzes the cleavage of ribonucleic acid targets into numerous small nucleic acid fragments, leading to an ECL signal. When Hg2+ is added, the thymine-thymine (T-T) mismatches of the Hg2+ aptamer bind Hg2+ to form the "T-Hg2+-T" structure, which not only inhibits the SPR process but also produces a large steric hindrance, thus quenching the ECL signal and allowing quantification of Hg2+. The novel ECL sensor quantifies Pb2+ in the range of 0.1 fM to 0.1 μM with a limit of detection of 0.07 fM and Hg2+ in the range of 10 pM to 1 μM with a LOD of 4.07 pM.

Metal-Organic framework incorporated luminescent PTCA combined with novel co-reactant accelerator for ultra-sensitive electrochemiluminescence detection of CA19-9

Polycyclic aromatic hydrocarbons (PAHs) are commonly used as electrochemiluminescence (ECL) luminophores. However, PAHs are limited by the aggregation-caused quenching (ACQ) effect, which reduces ECL emission. Therefore, developing an ECL system from PAHs with efficient luminescence is a significant challenge. In this work, a two-ligand strategy was proposed to assemble 3, 4, 9, 10-perylenetetracarboxylic acid (PTCA) into zeolitic imidazole framework-8 (ZIF-8). The ACQ effect of PTCA was inhibited by participating in the formation of metal–organic frameworks (MOFs) and a luminescent ZIF-8-PTC (Z8P) composite was obtained. Satisfactorily, conceptual experiments demonstrated that the significantly higher ECL efficiency of Z8P was achieved compared with PTCA monomers and aggregates. On the sensing substrate, a novel co-reactant accelerator (Au@MFNC) was used to achieve continuous catalysis of the persulfate (K2S2O8) with the Prussian blue analogues (PBAs) as a template under the efficient synergistic effect of MoS2. Through the reversible transformation of the transition metal valence states, a sufficient amount of sulfate radicals (SO4•−), again amplifying the ECL signal of Pd@Z8P. Under ideal conditions, the constructed dual-MOFs ECL immunosensor had a wide response range (1 × 10−4 − 1 × 102 U/mL) and a low limit of detection (LOD) (6 × 10−5 U/mL), which provided an alternative method for CA19-9 ultrasensitive detection, and broadened a new idea for the development of high-performance luminescent MOFs.

Silica Nanochannels as Nanoreactors for the Confined Synthesis of Ag NPs to Boost Electrochemical Stripping Chemiluminescence of the Luminol-O2 System for the Sensitive Aptasensor.

Herein, we, for the first time, synthesize silver nanoparticles (Ag NPs) within the nanochannels of amino group-functionalized vertically ordered mesoporous silica films (NH2-VMSF) and investigate their coreaction accelerator role in the luminol-dissolved oxygen (O2) electrochemical stripping chemiluminescence (ESCL) system. The synthesized Ag NPs are capable of electrocatalytic reduction of O2 to superoxide radicals, and meanwhile, sliver ions (Ag+) electrochemically stripped from Ag NPs can promote the amount of luminol anion radicals, generating the boosted ECL intensity of the luminol-dissolved O2 system. This proposed Ag NPs@NH2-VMSF on the indium tin oxide electrode was applied to construct the ESCL aptasensor for quantitative determination of prostate-specific antigen (PSA), yielding a low detection limit [0.19 pg/mL (S/N = 3)] and a broad linear dynamic range (1 pg/mL to 100 ng/mL). Furthermore, good analytical performance of PSA in serum with satisfactory recoveries and low relative standard deviation values is achieved by our developed ESCL aptasensor, rendering it a convenient and sensitive method for PSA determination in clinical applications and further broadening the strategy of ESCL techniques.

Ultrastable Luminol-OH--(Ni-WOx-CNT) ECL System with High Strength and Its Applications in Sensing.

In traditional luminol electrochemiluminescence (ECL) systems, hydrogen peroxide (H2O2) and dissolved oxygen (DO) are the commonly used coreactants to generate reactive oxygen species (ROS) for ECL emission. However, the self-decomposition of hydrogen peroxide and the limited solubility and content of oxygen in solution undoubtedly restrict the luminescence efficiency and stability of the luminol ECL system. Inspired by the ROS-mediated ECL mechanism, we pioneered hydroxide ion as an advanced luminol ECL coreactant using nickel-doped and carbon nanotube-modified tungsten oxide (Ni-WOx-CNT) as the coreactant accelerator. Owing to the excellent catalytic activity of Ni-WOx-CNT, amounts of ROS were generated from OH- at a low excitation voltage, which subsequently reacted with luminol anion radicals and triggered intense ECL signals. Experiments confirmed an impressive ECL behavior in terms of high luminescent intensity (85,563 a.u.) and super stability over 1300 consecutive tests; both are superior to those recently reported luminol-H2O2 and luminol-DO systems with smaller ECL intensities and consecutive tests less than 25 times. To validate the feasibility and versatility of the developed system in sensor, traditional three-electrodes system and closed bipolar electrodes system with various sensing strategies of direct oxidation, "gate-effect" of molecularly imprinted polymer, immune reaction, and enzyme-catalyzed reaction were proposed to monitor uric acid (UA), C-reactive protein (CRP), immunoglobulin G (IgG), and glucose (Glu). The superior sensing performances confirmed the great application potential of the developed ROS-mediated ECL system.

Binary-amplifying electrochemiluminescence sensor for sensitive assay of catechol and luteolin based on HKUST-1 derived CuO nanoneedles as a novel luminophore

Herein, a highly novel and effective electrochemiluminescence (ECL) sensor based on metal-organic framework (MOF, HKUST-1) derived CuO nanoneedles (HKUST-1 derived CuO NNs), gold nanoparticles (AuNPs) and TiO2 was developed for ultrasensitive detection of catechol and luteolin. The HKUST-1 derived CuO NNs were employed as luminophore for the first time, which were successfully fabricated by using HKUST-1 as precursor. The results revealed that the HKUST-1 derived CuO NNs exhibit excellent ECL activity ascribed to its abundant active site and the high specific surface area, thus obviously promoting the separation and transfer of charge and further improving the current density of ECL sensor. To binary-amplify the signal of the ECL sensor, the AuNPs and TiO2 nano-materials with good biocompatibility, great electron transport efficiency and high catalytic activity were used as co-reaction accelerators in the ECL process. Dependent on the above brilliant strategy, the proposed ECL sensor achieved wide linear ranges from 3 × 10−9 – 1 × 10−4 M for catechol and 1 × 10−8 – 2 × 10−4 M for luteolin, with the detection limits of 1.5 × 10−9 M for catechol and 5.3 × 10−9 M for luteolin, respectively. Furthermore, the ECL sensor exhibited outstanding selectivity, repeatability, stability and obtained great feedback on determination of catechol and luteolin in actual samples. The method not only filled a gap in the ECL application of MOF-derived materials but also provided a novel sight for design other highly efficient luminescent materials.

PdPt@SnS2 Nanosheets for a Novel Ultrasensitive Electrochemiluminescence Biosensor for miRNA-21 Assay.

PdPt nanosheets decorated on SnS2 nanosheets (i.e., PdPt@SnS2 NSs) were fabricated for a novel electrochemiluminescence (ECL) biosensor for ultrasensitive detection of miRNA-21 based on catalytic hairpin assembly (CHA) cycles. The PdPt@SnS2 NSs serve as both the main luminophore and a highly effective coreaction accelerator in the ECL biosensor. In the CHA cycles, more miRNA-21 is captured, and the performance of the ECL biosensor is improved. When miRNA-21 is present, the hairpin chain DNA1 (i.e., H1) is opened, and the ferrocene (Fc)-modified hairpin chain DNA2 (i.e., Fc-H2) hybridizes with as-opened H1 by replacing miRNA-21 to stimulate CHA cycles of miRNA-21. During the CHA cycles, Fc-H2 quenches the ECL signal to monitor miRNA-21. As a result, the ECL biosensor shows ultrasensitive and highly selective detection of miRNA-21 from 1 aM to 1 nM with a detection limit (LOD) of 0.02 aM. In addition, the ECL biosensor exhibits excellent practicality for miRNA-21 detection in human serum samples.

Low-triggering-potential electrochemiluminescence based on mental-organic frameworks encapsulation of ruthenium for synthetic cathinone detection by coupling photonic crystal light-scattering signal amplification of covalent-organic frameworks

Developing effective electrochemiluminescence (ECL) platforms is always an essential concern in highly sensitive bioanalysis. In this work, a low-triggering-potential ECL sensor was designed for detecting synthetic cathinone 3,4-methylenedioxypyrovalerone (MDPV) based on a dual-signal amplification strategy. Initially, a probe was created by integrating Ruthenium into the hollow porphyrin-based MOF (PCN-222) structure to decrease the excitation potential and enhance ECL performance without external co-reaction accelerators. Additionally, for the first time, photonic crystals (PCs) assembled from covalent organic frameworks (COFs) were employed to amplify the ECL signal, thereby increasing the photon flux and the loading capacity of the ECL emitter to enhance sensitivity of the sensor. In the presence of the target MDPV, the aptamer labeled with Ferrocene (Fc) experienced conformational changes, causing Fc to approach the luminophore and resulting in ECL quenching. This effect was attributed to aptamer's conformational changes induced by the target, directly correlating with the target concentration. The constructed sensor showed good linearity with the target MDPV concentration, covering a dynamic range from 1.0 × 10−14 to 1.0 × 10−6 g/L and achieved an ultra-low detection limit of 4.79 × 10−15 g/L. This work employed dual amplification strategies to enhance ECL signals effectively, providing a novel method for developing highly responsive and bioactive sensors.

Single-Atom Iron Doped Carbon Dots with Highly Efficient Electrochemiluminescence for Ultrasensitive Detection of MicroRNAs.

Herein, single-atom iron doped carbon dots (SA Fe-CDs) were successfully prepared as novel electrochemiluminescence (ECL) emitters with high ECL efficiency, and a biosensor was constructed to ultrasensitively detect microRNA-222 (miRNA-222). Importantly, compared with the conventional without single-atom doped CDs with low ECL efficiency, SA Fe-CDs exhibited strong ECL efficiency, in which single-atom iron as an advanced coreactant accelerator could significantly enhance the generation of reactive oxygen species (ROS) from the coreactant S2O82- for improving the ECL efficiency. Moreover, a neoteric amplification strategy combining the improved strand displacement amplification with Nt.BbvCI enzyme-induced target amplification (ISDA-EITA) could produce 4 output DNAs in every cycle, which greatly improved the amplification efficiency. Thus, a useful ECL biosensor was built with a detection limit of 16.60 aM in the range of 100 aM to 1 nM for detecting traces of miRNA-222. In addition, miRNA-222 in cancer cell lysate (MHCC-97L) was successfully detected by using the ECL biosensor. Therefore, this strategy provides highly efficient single-atom doped ECL emitters for the construction of sensitive ECL biosensing platforms in the biological field and clinical diagnosis.

Tuning electrochemical water activation over NiIr single-atom alloy aerogels for stable electrochemiluminescence

The anodic oxygen evolution reaction is a well-acknowledged side reaction in traditional aqueous electrochemiluminescence (ECL) systems due to the generation and surface aggregation of oxygen at the electrode, which detrimentally impacts the stability and efficiency of ECL emission. However, the effect of reactive oxygen species generated during water oxidation on ECL luminophores has been largely overlooked. Taking the typical luminol emitter as an example, herein, we employed NiIr single-atom alloy aerogels possessing efficient water oxidation activity as a prototype co-reaction accelerator to elucidate the relationship between ECL behavior and water oxidation reaction kinetics for the first time. By regulating the concentration of hydroxide ions in the electrolyte, the electrochemical oxidation processes of both luminol and water are finely tuned. When the concentration of hydroxide ions in electrolyte is low, the kinetics of water oxidation is attenuated, which limits the generation of oxygen, effectively mitigates the influence of oxygen accumulation on the ECL strength, and offers a novel perspective for harnessing side reactions in ECL systems. Finally, a sensitive and stable sensor for antioxidant detection was constructed and applied to the practical sample detection.

Controlled-Release Electrochemiluminescence Biosensor with Strong Self-On Effect by a Multiple Signal Amplification Strategy for Trace Detection of Prostate-Specific Antigen.

The enhancement of sensitivity in biological analysis detection can reduce the probability of false positives of the biosensor. In this work, a novel self-on controlled-release electrochemiluminescence (CRE) biosensor was designed by multiple signal amplification and framework-enhanced stability strategies. As a result, the changes of the ECL signal were enhanced before and after the controlled-release process, achieving sensitive detection of prostate-specific antigen (PSA). Specifically, for one thing, Fe3O4@CeO2-NH2 with two paths for enhancing the generation of coreactant radicals was used as the coreaction accelerator to boost ECL performance. For another, due to the framework stability, zeolitic imidazolate framework-8-NH2 (ZIF-8-NH2) was combined with luminol to make the ECL signal more stable. Based on these strategies, the constructed CRE biosensor showed a strong self-on effect in the presence of PSA and high sensitivity in a series of tests. The detection range and limit of detection (LOD) were 5 fg/mL to 10 ng/mL and 2.8 fg/mL (S/N = 3), respectively, providing a feasible approach for clinical detection of PSA.

Silver Nanoparticles In Situ Enhanced Electrochemiluminescence of the Porphyrin Organic Matrix for Highly Sensitive and Rapid Monitoring of Tetracycline Residues.

Accurate monitoring of tetracycline (TC) residues in the environment is crucial for avoiding contaminant risk. Herein, a novel TC biosensor was facilely designed by integrating silver nanoparticles (Ag NPs) into the porphyrin metal-organic matrix (Ag@AgPOM) as a bifunctional electrochemiluminescence (ECL) probe. Different from the step-by-step synthesis of the co-reaction accelerator and ECL emitter, the co-reaction accelerators Ag NPs were in situ-grown on the surface of 5,10,15,20-tetrakis (4-carboxyphenyl) porphyrin (TCPP) via a simple one-pot approach. Symbiotic Ag NPs on Ag@AgPOM formed an intimate interface and increased the collision efficiency of the ECL reaction, achieving the ECL enhancement of TCPP. Under the optimized conditions, the ternary ECL biosensor showed a wide linear detection range toward TC with a low detection limit of 0.14 fmol L-1. Compared with the traditional HPLC and ELISA methods, satisfied analytical adaptability made this sensing strategy feasible to monitor TC in complex environmental samples.

Highly efficient electrochemiluminescence based on Lu@Ov-ZMO as an ECL emitter for ultrasensitive detection of CA242

An effective electrochemiluminescence (ECL) emitter, luminol@oxygen vacancies-ZnMn2O4 (Lu@Ov-ZMO), was prepared to fabricate a novel luminol/H2O2-O2/Ov-ZMO ECL system for ultrasensitive detection of carbohydrate antigen 242 (CA242). The integrated design of co-reaction accelerator ZMO and luminol effectively shortened the electron transfer distance in the ECL system. Meanwhile, the abundant oxygen vacancies in ZMO further promoted the generation of more superoxide anion radicals (O2.-), which further improved the ECL luminescence efficiency. The resonance energy transfer (RET) strategy was used to construct the signal-off ECL immunesensor with PDA@SiO2 as the quencher. The fabricated immunosensor showed a good linear range of 0.01 mU/mL to 100 U/mL with a detection limit of 3.3 μU/mL (S/N = 3) under the optimum experimental conditions. This work put forward a new method of integrating luminophore and OVs enriched accelerator with wonderful signal-amplification strategy to formulate a functional immunosensor for early disease diagnostics.

A novel self-enhanced ECL-RET aptasensor based on the bimetallic MOFs with homogeneous catalytic sites for kanamycin detection

The inappropriate use of antibiotics undoubtedly poses a potential threat to public health, creating an increasing need to develop highly sensitive tests. In this study, we designed a new type of porphyrin metal-organic frameworks (Fe TCPP(Zn) MOFs) with homogeneous catalytic sites. The ferric-based metal ligands of Fe TCPP(Zn) MOFs acted as co-reaction accelerators, which effectively improved the conversion efficiency of H2O2 on the surface of MOFs, then increased the concentration of •OH surrounding porphyrin molecules to achieve self-enhanced electrochemiluminescence (ECL). Based on this, an aptasensor for the specific detection of kanamycin (KAN) in food and environmental water samples was constructed in combination with resonance energy transform (RET), in which Fe TCPP(Zn) MOFs were used as luminescence donor and AuNPs were used as acceptor. Under the best conditions, there was a good linear relationship between the ECL intensity and the logarithm of KAN concentration with a detection limit of 0.28 fM in the range of 1.0 × 10−7–1.0 × 10−13 M, demonstrating satisfactory selectivity and stability. At the same time, the complexity of the detection environment was reduced, which further realized the reliable analysis of KAN in milk, honey and pond water. Overall, this innovative self-enhanced ECL strategy provides a novel approach for constructing efficient ECL systems in MOFs, and also extends the application of MOFs to the analysis and detection of trace antibiotics in food and the environment.

Strong aggregation-induced electrochemiluminescence of pyrene-coordination metal-organic frameworks coupled with zero-valent iron as novel accelerator for ultrasensitive immunoassay

Polycyclic aromatic hydrocarbons (PAHs) are excellent alternative luminophores for electrochemiluminescence (ECL) immunoassays. However, they are inevitably limited by the aggregation-caused quenching effect. In this study, aimed at eliminating the aggregation quenching of PAHs, luminescent metal–organic frameworks (MOFs) with 1,3,6,8-tetra(4-carboxybenzene)pyrene (H4TBAPy) as the ligand were exploited as a novel nano-emitter for the construction of ECL immunoassays. The luminophore exhibits efficient aggregation-induced emission enhancement, good acid-base resistance property and unusual ECL reactivity. In addition, the simultaneous use of potassium persulfate and hydrogen peroxide as dual co-reactants resulted in a synergistic enhancement of the cathodic ECL efficiency. The use of magnetic iron-nickel alloys as the multifunctional sensing platform can further enhance the ECL activity, and its enriched zero-valent iron as a co-reactant accelerator effectively drives ECL analytical performance. Profiting from the excellent characteristics, signal-on ECL immunoassays have been constructed. With carcinoembryonic antigen as the model analysis target, a detection limit of 0.63 pg/mL was obtained within the linear range of 1 pg/mL to 50 ng/mL, accompanied by excellent analytical performance. This report opens a new window for the rational design of efficient ECL illuminators, and the proposed ECL immunoassays may find promising applications in the detection of disease markers.