Electrochemiluminescence Applications Research Articles

Stimuli-Responsive DNA Nanomachines for Intracellular Targeted Electrochemiluminescence Imaging in Single Cells.

Electrochemiluminescence (ECL) microscopy has emerged as a powerful technique for single-cell imaging owing to its unparalleled background-free imaging advantages. However, controlled intracellular ECL imaging remains challenging. Here, we developed a stimuli-responsive self-assembled DNA nanomachine that enables the ECL imaging of intracellular target biomolecules in single cells. The ECL nanoprobe consists of an ECL nanoemitter constructed from Ru(bpy)32+-doped metal-organic framework as the nanoreactor core, with a DNA polymer hydrogel shell (DNAgel) acting as the stimuli-gated layer. The outer functionalized DNAgel of the ECL nanoprobe was specifically designed to block ECL generation and to dissociate by ATP molecules, thereby enabling selective recovery of ECL emission capability. Such an engineered stimuli-responsive nanomachine successfully achieved the targeted ECL imaging of intracellular ATP distribution with spatial resolution. In addition, ECL imaging of various intracellular biomolecules should be generalizable by simply changing the switching DNA sequence of the probe. Our research provided a reliable strategy for ECL microscopy within cells, which will broaden the application of ECL in single-cell and single-molecule profiling.

Laser-Treated Screen-Printed Carbon Electrodes for Electrochemiluminescence imaging.

Electrochemiluminescence (ECL) is nowadays a powerful technique widely used in biosensing and imaging, offering high sensitivity and specificity for detecting and mapping biomolecules. Screen-printed electrodes (SPEs) offer a versatile and cost-effective platform for ECL applications due to their ease of fabrication, disposability, and suitability for large-scale production. This research introduces a novel method for improving the ECL characteristics of screen-printed carbon electrodes (SPCEs) through the application of CO2 laser treatment following fabrication. Using advanced ECL microscopy, we analyze three distinct carbon paste-based electrodes and show that low-energy laser exposure (ranging from 7 to 12 mJ·cm-2) enhances the electrochemical performance of the electrodes. This enhancement results from the selective removal of surface binders and contaminants achieved by the laser treatment. We employed ECL microscopy to characterize the ECL emission using a bead-based system incorporating magnetic microbeads, like those used in commercial platforms. This approach enabled high-resolution spatial mapping of the electrode surface, offering valuable insights into its electrochemical performance. Through quantitative assessment using a photomultiplier tube (PMT), it was observed that GST electrodes could detect biomarkers with high sensitivity, achieving an approximate detection limit (LOD) of 11 antibodies per μm2. These findings emphasize the potential of laser-modified GST electrodes in enabling highly sensitive electrochemiluminescent immunoassays and various biosensing applications.

Enhanced Electrochemiluminescence at the Gas/Liquid Interface of Bubbles Propelled into Solution.

Electrochemiluminescence (ECL) is typically confined to a micrometric region from the electrode surface. This study demonstrates that ECL emission can extend up to several millimeters away from the electrode employing electrogenerated chlorine bubbles. The mechanism behind this bubble-enhanced ECL was investigated using an Au microelectrode in chloride-containing and chloride-free electrolyte solutions. We discovered that ECL emission at the gas/solution interface is driven by two parallel effects. First, the bubble corona effect facilitates the generation of hydroxyl radicals capable of oxidizing luminol while the bubble is attached to the surface. Second, hypochlorite generated from chlorine sustains luminol emission for over 200 s and extends the emission range up to 5 mm into the solution, following bubble detachment. The new approach can increase the emission intensity of luminol-based assays 5-fold compared to the conventional method. This is demonstrated through a glucose bioassay, using a midrange mobile phone camera for detection. These findings significantly expand the potential applications of ECL by extending its effective range in time and space.

Sensitive detection of uric acid based on low-triggering-potential cathodic luminol electrochemiluminescence achieved by ReS2 nanosheets.

The majority of previously reported cathodic electrochemiluminescence (ECL) systems often required very negative potential to be carried out, which hasgreatly limited their applications in the sensing field. Screening high-performance cathodic ECL systems with low triggering potential is a promising way to broaden their applications. In this work, rhenium disulfide nanosheets (ReS2 NS) have been revealed as an efficient co-promoter to realize low-triggering-potential cathodic luminol ECL. One strong cathodic ECL signal appeared at a potential of -0.3V and one anodic ECL peak was obtained at -0.15V under the reverse potential scan, which were caused by electrogenerated reactive oxygen species (ROS) from hydrogen peroxide. The generation of strong luminol ECL at low potential was the result of the electrocatalytic effect of ReS2 NS on the reduction of H2O2. The scavenging effect of uric acid (UA) on the ROS could significantly inhibit the cathodic ECL. As a result, an ECL sensor was proposed, which showed outstanding performance for the detection of UA in the range of 10nM to 0.1mM with a low detection limit of 1.53nM. Moreover, the ECL sensor was successfully applied in the sensitive detection of UA in real samples. This work provides anew avenue to establish a low-potential cathodic ECL system, which will sufficiently expand the potential application of cathodic ECL in the sensing field.

Highly Active Coreactant-Capped and Water-Stable 3D@2D Core-Shell Perovskite Quantum Dots as a Novel and Strong Self-Enhanced Electrochemiluminescence Probe.

Self-enhanced electrochemiluminescence (ECL) probes have attracted more and more attention in analytical chemistry for their significant simplification of the ECL sensing operation while improving the ECL sensing sensitivity. However, the development and applications of self-enhanced ECL probes are still in their infancy and mainly suffer from the requirement of a complicated synthesis strategy and relatively low self-enhanced ECL activity. In this work, we took advantage of the recently emerged perovskite quantum dots (PQDs) with high optical quantum yields and easy surface engineering to develop a new type of PQD-based self-enhanced ECL system. The long alkyl chain (C18) diethanolamine (i.e., N-octadecyldiethanolamine (ODA)) with high ECL coreactant activity was selected as a capping ligand to synthesize an ODA-capped PQD self-enhanced ECL probe. The preparation of the coreactant-capped PQDs is as simple as for the ordinary oleylamine (OAm)-capped PQDs, and the obtained ODA-capped PQDs exhibit very strong self-enhanced ECL activity, 82.5 times higher than that of traditional OAm-capped PQDs. Furthermore, the prepared ODA-PQDs have a unique nanostructure (ODA-CsPbBr3@CsPb2Br5), with the highly emissive 3D CsPbBr3 PQD as the core and the water-stable 2D CsPb2Br5 as the shell, which allows ODA-PQDs to be very stable in aqueous media. It is envisioned that the prepared ODA-3D@2D PQDs with the easy preparation method, strong self-enhanced ECL, and excellent water stability have promising applications in ECL sensing.

Hydrogen-Bonded Organic Cocrystal-Encapsulated Perovskite Nanocrystals as Coreactant-Free Electrochemiluminescent Luminophore for the Detection of Uranium.

Lead halide perovskite nanocrystals with excellent photophysical properties are promising electrochemiluminescence (ECL) candidates, but their poor stability greatly restricts ECL applications. Herein, hydrogen-bonded cocrystal-encapsulated CsPbBr3 perovskite nanocrystals (PeNCs@NHS-M) were synthesized by using PeNCs as nuclei for inducing the crystallization of melamine (M) and N-hydroxysuccinimide (NHS). The as-synthesized composite exhibits multiplicative ECL efficiencies (up to 24-fold that of PeNCs) without exogenous coreactants and with excellent stability in the aqueous phase. The enhanced stability can be attributed to the well-designed heterostructure of the PeNCs@NHS-M composite, which benefits from both moiety passivation and protection of the peripheral cocrystal matrix. Moreover, the heterostructure with covalent linkage facilitates charge transfer between PeNCs and NHS-M cocrystals, realizing effective ECL emission. Meanwhile, the NHS and M components act as coreactants for PeNCs, shortening the electron-transport distance and resulting in a significant increase in the ECL signal. Furthermore, by taking advantage of the specific binding effect between NHS-M and uranyl (UO22+), an ECL system with both a low detection limit (1 nM) and high selectivity for monitoring UO22+ in mining wastewater is established. The presence of UO22+ disrupted the charge-transfer effect within PeNCs@NHS-M, weakening the ECL signals. This work provides an efficient design strategy for obtaining stable and efficient ECLs from perovskite nanocrystals, offering a new perspective for the discovery and application of perovskite-based ECL systems.

Supramolecular assembly-induced electrochemiluminescence enhancement of gold nanoclusters for hemoglobin detection.

Gold nanoclusters (Au NCs) with excellent optical properties and biocompatibility have become one of the most promising electrochemiluminescence (ECL) emitters. However, the low efficiency and poor stability of Au NCs restrict their applications in ECL. Herein, by supramolecular assembly of L-arginine (Arg) and 4-hydroxy-2-mercapto-6-methylpyrimidine (MTU) on the surface of Au NCs, Arg/MTU-Au NCs with enhanced ECL efficiency and stability were prepared. Compared with the MTU-stabilized Au NCs (MTU-Au NCs), the ECL efficiency of Arg/MTU-Au NCs increased by 24.8 times. As a proof-of-concept, a sensitive biosensing platform was constructed for sensitive detection of hemoglobin (Hb) in urine using Arg/MTU-Au NCs as ECL emitters. The proposed ECL detection platform provides a feasible strategy for the detection of biomarkers in urine and has broad application prospects in disease screening and clinical marker detection.

Target-Driven Annular DNA Walker Coupled with Electrochemiluminescent Silicon Quantum Dots for APE1 Bioanalysis.

Functional DNA walkers with substantial nanostructures have been extensively investigated; however, their stability still faces challenges when exposed to diverse nuclease in clinical biological samples, resulting in the unreliability of actual assessment. This work proposed a target-driven annular DNA walker with enhanced stability enabling the sensitive and reliable response to different concentrations of apurinic/apyrimidinic endonuclease 1 (APE1), by preparing silicon quantum dots (SiQDs) as electrochemiluminescence (ECL) emitters. Specifically, the SiQDs showed significant strong and stable ECL signals by purifying the microenvironment of SiQDs through the dialysis removal of the gel-like layers surrounding the SiQDs. The relative standard deviation (RSD) of their ECL signal had been improved 16.59 times under consecutive scanning compared to that of SiQDs without dialysis, demonstrating a significant improvement in ECL stability. Subsequently, in the presence of APE1, the designed annular DNA walker was activated to move along the numerous quenching probes within the continuous cross-based DNA orbits, which were immobilized to the SiQD-modified electrode, providing ECL readout signals. The linear range of this ECL biosensor was 1.0 × 10-13 U·μL-1 to 1.0 × 10-7 U·μL-1, and the limit of detection (LOD) was as low as 1.766 × 10-14 U·μL-1. This work provides a novel structure of a DNA walker with nuclease resistance for clinical sample detection and designs a new strategy for synthesizing SiQDs with favorable ECL performance, tremendously expanding the ECL application of SiQDs.

Highly Efficient Dual-Color Luminophores for Sensitive and Selective Detection of Diclazepam Based on MOF/COF Bi-Mesoporous Composites.

Currently, studies on electrochemiluminescence (ECL) mainly focused on the single emission of luminophores while those on multi-color ECL were rarely reported. Here, a bi-mesoporous composite of the metal-organic framework (MOF)/covalent-organic framework (COF) with strong and stable dual-color ECL was prepared to construct a novel ECL sensor for sensitive detecting targets. A PTCA-COF with excellent ECL performance was loaded with a great amount of another ECL emitter Cu3(HHTP)2. Remarkably, the integrated composite had both ECL properties of PTCA-COF at 520 nm and Cu3(HHTP)2 at 600 nm wavelengths. Furthermore, Cu3(HHTP)2 with good electron transfer ability can greatly enhance the electrical conductivity and promote electrochemical activation. Thus, the simultaneous enhanced two-color ECL intensity and the catalytic properties of the conductive MOF exerted a dual enhancement effect on the ECL signal of the composite. Significantly, diclazepam can not only be adsorbed well on the multi-stage porous structure MOF/COF composite by π-π interactions but also selectively quench the ECL signal of the PTCA-COF, realizing the sensitive detection. The ECL sensor showed a wide detection range from 1.0 × 10-13 to 1.0 × 10-8 g/L, and the limit of detection (LOD) was as low as 2.6 × 10-14 g/L (S/N = 3). The proposed ECL sensor preparation method was simple and sensitive, providing a new perspective for the potential application of multi-color ECL in the sensing field.

Unique Electrochemiluminescent Behavior of two Quinolones, Enoxacin and Nadifloxacin, and their Sensing Application

This research looked at the electrochemiluminescence (ECL) signals of two quinolones: Enoxacin (Enox) and Nadifloxacin (Nadf), which were investigated in H3BO3-Na2B4O7 buffered solutions containing the co-reactant K2S2O8. Based on the fluorescence (FL) spectra, ECL spectra, and corresponding ECL experiments, a possible mechanism of the ECL reaction was proposed. The effect of experimental conditions on quinolone ECL behavior was studied and optimized, so we revealed the value of organic molecules as ECL luminophores. According to calculations, Nadifloxacin has a smaller LUMO-HOMO band gap than Enoxacin, making it more suitable for use as a luminophore. Furthermore, we discovered a quenching effect of lead ion (Pb2+) on the ECL signal of Nadifloxacin, and we focused on the Pb2+ quenching mechanism in this system and made reasonable guesses. We invented a novel technique for ECL detection of Pb2+ with high sensitivity and selectivity. This method demonstrates the potential application of ECL in pollution management.

An electrochemiluminescence insulin sensing platform based on the molecular recognition properties of cucurbit[7]uril

The establishment of new mechanisms for target identification and signal amplification continues to drive innovation in electrochemiluminescence (ECL) sensing platforms. In this paper, a novel ECL insulin sensing platform was constructed by utilizing the molecular recognition properties of cucurbit[7]uril. Specifically, the macrocyclic host molecule cucurbit[7]uril was immobilized on the surface of the sensing platform as an identification probe, which could selectively capture insulin according to the inherent properties of the protein N-terminal. Introducing the rigid molecule cucurbit[7]uril into the sensing interface could reduce the influence of the environmental parameters on the sensing system, which provides a reliable guarantee for the accurate detection of insulin. Furthermore, gold nanoclusters were modified by utilizing the molecular recognition properties of cucurbit[7]uril, and used as anode signal probes for ECL sensing platform. The macrocyclic molecules cucurbit[7]uril passivated the surface of the nanoclusters, inhibited the non-radiative relaxation and improved the physical stability of the luminophore, leading to a significant increase in the sensitivity and stability of the ECL probe. The ECL sensing platforms exhibited a linear range from 50.00 fg/mL to 100.0 ng/mL, with a detection limit of 5.44 fg/mL. This study revealed the critical role of cucurbit[7]uril in target recognition and signal amplification, extending the scope of supramolecular applications in ECL.

Electrochemiluminescence Amplification in Bead-Based Assays Induced by a Freely Diffusing Iridium(III) Complex.

Heterogeneous electrochemiluminescence (ECL) assays employing tri-n-propylamine as a co-reactant and a tris(2,2'-bipyridine)ruthenium(II) ([Ru(bpy)3]2+) derivative as an emissive label are integral to the majority of academic and commercial applications of ECL sensing. This model system is an active research area and constitutes the basis of successfully commercialized bead-based ECL immunoassays. Herein, we propose a novel approach to the enhancement of such conventional ECL assays via the incorporation of a second metal coordination complex, [Ir(sppy)3]3- (where sppy = 5'-sulfo-2-phenylpyridinato-C2,N), to the experimental system. By employing ECL microscopy, we are able to map the spatial distribution of ECL emission at the surface of the bead, from [Ru(bpy)3]2+ labels, and solution-phase emission, from [Ir(sppy)3]3-. The developed [Ir(sppy)3]3--mediated enhancement approach elicited a significant improvement (70.9-fold at 0.9 V and 2.9-fold at 1.2 V vs Ag/AgCl) of the ECL signal from [Ru(bpy)3]2+ labels immobilized on the surface of a polystyrene bead. This dramatic enhancement in ECL signal, particularly at low oxidation potentials, has important implications for the improvement of existing heterogeneous ECL assays and ECL-based microscopy, by amplifying the signal, opening new bioanalytical detection schemes, and reducing both electrode surface passivation and deleterious side reactions.

Enzymes Encapsulated within Alginate Hydrogels: Bioelectrocatalysis and Electrochemiluminescence Applications.

A simple procedure to incorporate enzymes (horseradish peroxidase, HRP, and lactate oxidase, LOx) within alginate hydrogels is reported with electrochemiluminescence (ECL) used to detect the enzymatic reactions with the corresponding substrates. First, HRP and LOx were successfully immobilized into CaCO3 microspheres, followed by the electrostatic layer-by-layer deposition of a nanoshell onto the microspheres, and finally by their dispersion into alginate solution. The as-prepared dispersion was drop cast onto the glassy carbon electrodes and cross-linked by the external and internal gelation methods using Ca2+ cations. The enzymes encapsulated within the alginate hydrogels were characterized using cyclic voltammetry and kinetic studies performed using ECL. The results showed that the enzymatic activity was significantly maintained as a result of the immobilization, with values of the apparent Michaelis-Menten constants estimated as 7.71 ± 0.62 and 8.41 ± 0.43 μM, for HRP and LOx, respectively. The proposed biosensors showed good stability and repeatability with an estimated limit of detection of 5.38 ± 0.05 and 0.50 ± 0.03 μM for hydrogen peroxide and lactic acid, respectively. The as-prepared enzymes encapsulated within the alginate hydrogels showed good stability up to 28 days from their preparation. The sensitivity and selectivity of the enzymes encapsulated within the alginate hydrogels were tested in real matrices (HRP, hydrogen peroxide, in contact lens solution; LOx, lactic acid in artificial sweat) showing the sensitivity of the ECL detection methods for the detection of hydrogen peroxide and lactic acid in real samples.

Gold Nanocluster Probe-Based Electron-Transfer-Mediated Electrochemiluminescence Sensing Strategy for an Ultrasensitive Copper Ion Detection.

Exploration of a novel and efficient sensing mechanism of Au nanocluster (AuNC)-based electrochemiluminescence (ECL) sensors is still a great challenge and opportunity for further applications. Herein, we proposed that the electron transfer (ET) could be used as a novel sensing regulation factor for the construction of an ECL-sensing platform based on the AuNC probe. As a proof-of-concept, the ECL quenching effect and mechanism of Cu2+ on pre-oxidation-treated l-methionine-capped AuNCs (OM-AuNCs) was investigated in detail. The results revealed that after the electrochemical excitation of the AuNC probe, the electron is transferred from the highest occupied molecular orbital (HOMO) of Met-Cu2+ to that of the OM-AuNCs, along with the ET from lowest-unoccupied molecular orbital (LUMO) of the OM-AuNCs back to the HOMO of Met-Cu2+, leading to the ECL quenching of OM-AuNCs. Since the ECL intensity of OM-AuNCs is sensitively affected by the ET process, a preferable linear dependence was obtained in the concentration range from 1.0 × 10-18 to 1.0 × 10-14 M with high selectivity. More importantly, a record low detection limit (LOD, 2.3 × 10-20 M) at the single copper ion level has been realized without any other amplification technique. Furthermore, the actual sample detection for Cu2+ exhibited satisfactory results. Therefore, this study enriches an ET-mediated ECL application and promotes a more rational design of ECL sensors.

An electrochemiluminescence biosensor based on morphology controlled iridium complex nanomaterials for SARS-CoV-2 nucleocapsid protein detection

The morphology of electrochemiluminescence (ECL) emitters is closely related to ECL properties, thus the control of their morphology is greatly essential for ECL applications. Herein, a facile nanoprecipitation method was developed to realize controllable morphology of iridium complex nanomaterials by modulating the volume ratio of poly(styrene-co-maleicanhydride) (PSMA) to tris (2-phenylpyridine) iridium(Ⅲ) (Ir(ppy)3). Furthermore, ECL properties of iridium complex nanomaterials with different morphologies were explored through a series of experiments. Iridium complex nanoparticles (Ir NPs) with excellent ECL performance were selected as admirable ECL emitters to construct biosensors. Ir NPs served as the matrix to stepwise capture primary antibody, antigen of SARS-CoV-2 nucleocapsid protein (ncovNP) and secondary antibody bioconjugate coupled with dual quenchers and detection antibody. Taking advantage of the significant quenching effect of noradrenaline (NA) and gold nanoparticles (Au NPs) in the secondary antibody bioconjugate on ECL emission from Ir NPs, the developed ECL biosensor realized the sensitive detection of ncovNP and the detection limit was as low as 47 fg/mL. The integration of morphology-controlled iridium complex nanomaterials and dual quenchers NA and Au NPs provides a promising ECL platform.

The role of doping strategy in nanoparticle-based electrochemiluminescence biosensing

Doping plays a crucial role in electrochemiluminescence (ECL) due to the followings: (1) Modulation of electronic structure, alteration of the surface state of nanoparticles (NPs), providing effective protection from the surrounding environment, thereby leading to ECL emitters with exceptional properties including tunable spectra, high luminescence efficiency, low excitation potential, and good stability. (2) Employment of doped NPs as promising coreactant alternatives due to the presence of functional groups such as amines induced by NP doping. (3) Serving as novel co-reaction accelerators (CRAs) for ECL through doping induced high catalytic properties. (4) Behaving as excellent carriers to load ECL emitters, recognition elements, and catalysts due to doping-induced larger surface area, higher conductivity and better biocompatibility of NPs. As a consequence, doped NPs have aroused broad interest and found wide applications in various ECL sensing platforms. In this review, the current promising improvements, concepts, and excellent applications of doped NPs for ECL biosensing are addressed. We aim to bring to light the physicochemical characteristics of various doped NPs that endow them with appealing ECL performance, leading to diverse applications in biosensing.

Electrochemiluminescent Ion-Channeling Framework for Membrane Binding and Transmembrane Activity Assays.

Recent upgrades in the electrochemiluminescence (ECL) technique showcased its brilliant knack in probing microscopic biointerfacial events, many of which were actually underlain by the ionotropic membrane processes, yet not being ostensive. Here, by modeling an artificial lipoid-supported porin ensemble, we explore and establish the ECL potency in profiling ion-channel activities. A lipophilic hollowed construct dubbed ZnPC was made out of the dynamic covalent chemistry, and its unique geometry was characterized that configured stoichiometric ECL-emissive units in a cubic stance; while the aliphatic vertices of ZnPC helped it safely snorkel and steadily irradiate in a biofilm fusion. After expounding basic ECL properties, the brightness was traced out in response to halogen contents that was lit up by F-/Cl- but down by Br-/I-. The overall pattern fitted the Langmuir isotherm, from which the membrane-binding strengths of the four were analyzed, compared, and collaterally examined in impedimetrics. On the other hand, one could derive anionic transmembrane kinetics from the time-dependent ECL statistics that pinpointed the ECL signaling via the nanocage-directed mass-transfer pathway. More data mining unveiled an ECL-featured Hofmeister series and the thermodynamic governing force behind all scenes. Finally, combining with halide-selective fluorometry, the synthetic conduit was identified as an ECL symporter. In short, this work develops a novel ECL model for the evaluation of life-mimicking membrane permeation. It might intrigue the outreach of ECL applications in the measurement of diverse surface-confined transient scenarios, e.g., in vitro gated ion or molecule trafficking, which used to be handled by nanopore and electrofluorochromic assays.

Electrochemiluminescence Resonance Energy Transfer System Based on Silver Metal-Organic Frameworks as a Double-Amplified Emitter for Sensitive Detection of miRNA-107.

As a class of electrochemiluminescence (ECL) enhancers, silver-based materials have broad application prospects. In this work, a novel silver metal-organic framework (AgMOF) was developed as a self-enhanced ECL emitter by one-step mixing and standing at room temperature. The AgMOF could produce strong and stable ECL emissions based on a double-amplification method, which originated from the aggregation-induced ECL emission of ligands and catalyzing S2O82- to produce more SO4•- by silver. Moreover, an ECL resonance energy transfer (ECL-RET) biosensor with AgMOF as a donor and BHQ2 as an acceptor was fabricated by duplex-specific nuclease (DSN)-assisted target recycling amplification to detect miRNA-107. The biosensor exhibited a strong ECL-RET effect due to the higher ECL emission of the AgMOF and perfect match of spectra between the AgMOF and BHQ2. Upon the introduction of DSN and target miRNAs, the specific DNA-RNA binding and nuclease cleaving could trigger the detachment of BHQ2, resulting in an increased ECL signal of AgMOF. Benefiting from the ECL-RET and DSN-assisted target recycling amplification methods, this biosensor achieved a wide linear relationship range from 20 to 120 fM with a low limit of detection (4.33 fM). This research presents an effective emitter for self-enhanced ECL systems, which broadens the potential ECL applications of silver-based nanomaterials.

Graphite-like Carbon Nitride Nanotube for Electrochemiluminescence Featuring High Efficiency, High Stability, and Ultrasensitive Ion Detection Capability.

Herein, for the first time, we introduced a novel electrochemiluminescence (ECL) luminophore based on a one-dimensional g-C3N4 nanotube using K2S2O8 as the coreactant. The g-C3N4 nanotube/K2S2O8 couple displayed very satisfactory ECL performance, i.e., an ECL efficiency (ΦECL) of 437% (vs 100% for the Ru(bpy)32+/K2S2O8 reference) and excellent ECL stability (the relative standard deviation (RSD) = 0.78%). By contrast, ΦECL and RSD of the control g-C3N4 nanosheet/K2S2O8 couple were merely 196% and 45.34%, respectively. The mechanism study revealed that the g-C3N4 nanotube features a large surface area and much lower interfacial impedance in the porous microstructure, which are beneficial for accelerating the charge transfer rate and stabilizing charge/excitons for ECL. Moreover, using the g-C3N4 nanotube/K2S2O8 system as a sensing platform, excellent Cu2+ detection capability was also achieved. Our work thus triggers a promising g-C3N4 nanomaterial system toward ECL application.

Deciphering the Mechanisms of Electrochemiluminescence by Spatially Resolved Measurements

AbstractElucidating the mechanisms of electrochemiluminescence (ECL) generation is crucial for developing novel ECL systems, designing new luminophores and coreactants, and expanding the application of ECL in different fields. Diverse methods have been developed so far for this purpose, among which spatially resolved measurements using ECL microscopy (ECLM), scanning electrochemical microscopy (SECM) and ECL self‐interference spectroscopy (ECLIS), are particularly valuable in terms of their ability to measure the distribution of excited luminophores and coreactant radicals. This review aims to provide an overview of research progress on deciphering the mechanisms of ECL by spatially resolved measurements. The reaction pathways for ECL generation are briefly introduced and then the advances in understanding the mechanisms of ECL reaction in solutions and on the surface of microbeads are summarized. A personal perspective covering both mechanisms and challenges is finally presented.