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Herein, highly efficient electrochemiluminescence (ECL) of novel Au–Ag bimetallic nanocluster @CNTs–TiO2 nanocomposites (Au–Ag NCs@CNTs–TiO2 NPs) with a unique “pearl necklace” structure was achieved. An ECL immunosensor was fabricated for simple, label-free and ultra-sensitive detection of cancer embryo antigen (CEA). The functionalized CNTs–TiO2 was used as a light-emitting carrier of Au–Ag NCs, TiO2 NPs were used as the co-reaction accelerator and dissolved O2 as the intrinsic co-reactant for the in situ generation of the strong oxidizing intermediate radical OH˙. OH˙ significantly influenced the ECL properties of metal NCs. Carbon nanotubes (CNTs) acted as conductors, enabling faster electron transfer and more effective energy transmission in the Au–Ag NCs@CNTs–TiO2 NP nanostructure. Compared with the ECL of pure Ag NCs, the ECL of Au–Ag NCs on the TiO2 NP surface was significantly enhanced due to the synergistic effect of bimetallic NCs. The experimental results showed that Au–Ag NCs@CNTs–TiO2 NPs achieved excellent ECL performance, and decreased the detection limit of the immunosensor for measuring CEA to 0.03 pg mL−1 in the absence of any additional signal amplification assay. The proposed ECL immunosensor is expected to be promising for applications in diagnostics and bioanalysis using other biomolecules.

It is the first time to develop electrochemiluminescence resonance energy transfer (ECRET) strategy using luminol-doped silica nanoparticles (luminol-SiNPs) for both “turn-off” detection of 2,4,6-trinitrophenol (TNP) and “turn-on” detection of anesthetic drug lidocaine hydrochloride (LDC). The spectral overlap of ECL emission of luminol-SiNPs with the absorption of TNP triggers ECRET from luminol-SiNPs to TNP and results in the decreased ECL signals. Besides, the specific interaction between TNP and LDC consumes TNP, accordingly prevents ECRET from luminol-SiNPs to TNP and achieves increasing ECL signals. The proposed ECRET strategy using luminol-SiNPs exhibits fast response (within 10 min), high sensitivity with LOD of 22.4 nM for TNP and 92.5 nM for LDC, respectively. It is also successfully applied in ECRET detection of TNP in lake water, LDC in human serum and commercial drug sample detections with satisfactory recoveries. More importantly, ECL of luminol-SiNPs is measured via linear sweep voltammetry by electrochemical reduction of dissolved oxygen at negative potential (– 1 V) and in no need of adding hydrogen peroxide (H2O2). Reactive oxygen species be generated in situ and make luminol-SiNPs system emit ECL, which makes ECL of the whole luminol-SiNPs system more stable than luminol-H2O2 system.

Herein, the electrochemiluminescence (ECL) donor Ru(bpy)32+-doped silica nanoparticles (RuSiNPs) and acceptor methylene blue (MB) were combined to achieve electrochemiluminescence resonance energy transfer (ECRET) using the overlap of the ECL emission of RuSiNPs with the absorption of MB. Owing to the ECRET from RuSiNPs to MB, the ECL of RuSiNPs was quenched by MB. During the oxidation of glucose catalysed by MB only under an alkaline condition, MB with blue color is reduced to the colourless form methylene white by glucose; this is accompanied by the disappearance of absorbance at 650 nm. Accordingly, ECRET was inhibited after the addition of glucose to the RuSiNP and MB mixture. Therefore, the ECL “turn-on” detection of glucose was achieved via the proposed ECRET strategy. The proposed ECRET method exhibited high sensitivity for glucose detection with the limit of detection (LOD) of 85.4 nM, selectivity towards glucose in the presene of metal ions, anions, dopamine or uric acid, and fast response within 5 min; moreover, it was successfully applied for glucose detection in human serum samples, and the average recoveries of 99.33%, 99.73% and 100.07% were obtained. This widens the application of ECRET in bioanalysis.

A highly sensitive sandwiched luminol electrochemiluminescence (ECL) immunosensor has been constructed based on the double catalysis effect and multiamplification strategy of platinum-gold alloy hybrid functionalized zinc oxide nanocomposites (Pt-Au@ZnONPs). First, the improved surface area and excellent biocompatibility of Pt-Au@ZnONPs were used for binding the secondary antibody (Ab2) and glucose oxidase (GOD) to obtain the novel bioconjugate Pt-Au@ZnONPs-GOD-Ab2. Pt-Au@ZnONPs and the loaded GOD amplified luminol ECL signals and promoted the luminol ECL response by efficiently catalyzing glucose to produce hydrogen peroxide (H2O2) in situ as a coreactant of luminol. Then, Pt-Au@ZnONPs catalyzed H2O2 to generate various reactive oxygen species (ROSs) that accelerated the ECL reaction of luminol, thus enhanced the ECL intensity of luminol and improved the sensitivity of the immunosensor. Second, gold nanoparticles decorated reduced graphene sheets (AuNPs@GS) with large specific surface area, good biocompatibility, high conductivity, and high catalytic activity were prepared and used as substrate of the immunosensor to capture the primary antibody (Ab1). Experimental results demonstrated that the proposed ECL immunosensor showed a sensitive response for the detection of α-1-fetoprotein (AFP) from 0.1 pg mL−1 to 200 ng mL−1 with detection limit of 0.03 pg mL−1 (S/N = 3). The as-proposed luminol ECL immunosensor has excellent sensitivity, stability, and specificity, which makes it very promising for clinical applications.

An ultrasensitive sandwich-type electrochemiluminescent (ECL) immunosensor suitable for identifying carcinoembryonic antigens (CEAs) was developed, using a metal–organic framework nanomaterial (AuNP@NPCGO) as an ideal loading platform and Ru(phen)32+-doped silica nanoparticles (RuSiNPs) as ECL signaling units. The AuNP@NPCGO nanocomposites were synthesized via in situ deposition of AuNPs on NPCGO as this configuration exhibits high conductivity, strong fixed ability, and excellent stability. The use of RuSiNPs as signaling units provided numerous luminophores that enhanced the ECL signals. Besides the aminated RuSiNPs, which had a large specific surface area and good biocompatibility, functioned as a superior matrix for immobilizing numerous secondary antibodies (Ab2). The proposed ECL immunosensor demonstrated excellent performance for CEA detection at concentrations of 0.01 ng mL−1 to 80 ng mL−1 with a detection limit of 0.003 ng mL−1 at a signal-to-noise ratio of three.

A sensitive electrochemiluminescent immunoassay for alkaline phosphatase (ALP) using p-nitrophenyl phosphate (PNPP) as substrate based on the electrochemiluminescence resonance energy transfer (ECRET) is developed. Luminol-doped silica nanoparticles (luminol-SiNPs) are prepared by water/oil (W/O) microemulsion method. PNPP convertes to p-nitrophenol (PNP) in the presence of ALP, which results in the absorption peak shifting from 360 nm to 450 nm. Herein the spectral overlap between absorption spectrum of PNP and electrochemiluminescence (ECL) spectrum of luminol-SiNPs (425 nm) makes energy transfer occur from luminol-SiNPs to PNP. In the optimized conditions, a linear relationship was obtained using this ECRET method at the concentration of ALP from 5 to 50 U/L (r = 0.9905) and with the limit of detection (LOD) of 0.8 U/L. This ECRET method exhibits sufficient specificity for ALP over other enzymes such as horseradish peroxidase, trypsin and lysozyme.

A method is presented for electrochemiluminescent (ECL) detection of the food additive curcumin via an energy transfer strategy and by using luminol-doped silica nanoparticles (luminol-NPs). The ECL emission of the luminol-NPs (peaking at 425 nm) is reduced in the presence of curcumin due to spectral overlap. The assay can be performed within 1 min, response is linear in the 0.1 to 100 µM curcumin concentration range, and the limit of detection is 32 nM. The method is selective over many ions, adenosine triphosphate, ascorbic acid, cysteine and folic acid. It was successfully applied to the determination of curcumin in spiked human serum and urine. The average recoveries range from 99.0 to 102.6%. Graphical abstract Electrochemiluminescence (ECL) "turn-off" detection of curcumin at levels as low as 32 nM via energy transfer using luminol-doped silica nanoparticles. No hydrogen peroxide (H

Traditional electrochemical systems generally require the direct connection of working electrode with potentiostat. They often employ two electrodes (a working electrode and a counter electrode) or three electrodes (a working electrode, a counter electrode, and a reference electrode) for a single electrochemical experiment. Different from traditional electrochemical systems, wireless electrochemical systems do not require the direct connection of working electrode with potentiostat. Conventional ipolar electrochemical system is a well-known wireless electrochemical system. It exerts potential control over electrolyte solutions with driving electrodes and redox reactions occur at the two opposite poles of the bipolar electrode. This enables simultaneous control of many bipolar electrode arrays with only two driving electrodes for multiplex experiments. Electrochemiluminescence, also called electrogenerated chemiluminescence (ECL), is light-emitting phenomenon generated from electrochemical reaction. The combination of bipolar electrochemical systems with ECL enables facile multiplex analysis. We present here several new wireless ECL systems, including wireless electrochemiluminescence, single-electrode ECL system, and wireless single-electrode ECL system [1-5]. Acknowledgment We are grateful for financial support from the National Key Research and Development Program of China (No. 2016YFA0201300), National Natural Science Foundation of China (Nos. 21804127,21874126,21675148), the Chinese Academy of Sciences (CAS)-the Academy of Sciences for the Developing World (TWAS), and President’s Fellowship Program, the CAS President's International Fellowship Initiative (PIFI) project. References Wenjing Qi, Jianping Lai, Wenyue Gao, Suping Li, Saima Hanif, Guobao Xu. Wireless Electrochemiluminescence with Disposable Minidevice. Chem., 2014, 86, 8927–8931. Liming Qi, Yong Xia, Wenjing Qi, Wenyue Gao, Fengxia Wu, Guobao Xu. Increasing Electrochemiluminescence Intensity of a Wireless Electrode Array Chip by Thousands of Times Using a Diode for Sensitive Visual Detection by a Digital Camera Chem., 2016, 88, 1123–1127. Fan Yuan, Liming Qi, Tadesse Haile Fereja, Dmytro V. Snizhko, Zhongyuan Liu, Wei Zhang, Guobao Xu. Regenerable bipolar electrochemiluminescence device using glassy carbon bipolar electrode, stainless steel driving electrode and cold patch. Electroc Acta, 2018, 262, 182-186. Xiangui Ma, Liming Qi, Wenyue Gao, Fan Yuan, Yong Xia, Baohua Lou, Guobao Xu. A portable wireless single-electrode system for electrochemiluminescent analysis. Electroc Acta, 2019, 308, 20-24. Wenyue Gao, Kateryna Muzyka, Xiangui Ma, Baohua Lou, Guobao Xu, A single-electrode electrochemical system for multiplex electrochemiluminescence analysis based on a resistance induced potential difference. Chem. Sci. 2018, 9, 3911-3916.

The applications of carbon nanotube (CNT) as solid-phase extraction matrix and bulk modification material in electrochemiluminescence (ECL) have been demonstrated for the first time. The bulk modification of Ru(phen) (2+)(3) has been achieved through the preparation of Ru(phen) (2+)(3)/Nafion modified CNT ceramic electrode. The bulk modification method has the advantages of easy electrode surface renewal and facile electrode preparation over surface immobilization approaches. Moreover, Ru(phen)(3)(2+)/Nafion modified CNT ceramic electrode can serve as an excellent solid- phase microextraction matrix because of the presence of CNT in the electrode. The combination of the Ru(phen)(3)(2+)/Nafion modified CNT ceramic electrode with solid-phase extraction enables ultrasensitive detection of perphenazine. The log-log calibration plot for perphenazine is linear from 1 x 10(-6) to 1 x 10(-11) M with a detection limit of 5.8 x 10(-12) M. The Ru(phen)(3)(2+)/Nafion modified CNT ceramic electrode shows better detection limit than Ru(phen)(3)(2+)/Nafion modified graphite ceramic electrode by about two orders of magnitude because of strong adsorption capacity and large adsorbing area of multi-walled CNT as well as low ECL background. It is one of the most sensitive methods for the Ru(phen)(3)(2+) ECL determination of coreactants so far. The detection takes less than 3 min, which makes this method promising for on-site detection. This method was also successfully applied for the determination of perphenazine in human urine samples spiked with perphenazine. The Ru(phen)(3)(2+)/Nafion modified CNT ceramic electrode exhibits outstanding long-term stability and reproducibility. The remarkable extraction capability and outstanding long-term stability of Ru(phen)(3)(2+)/Nafion modified CNT ceramic electrode as well as the advantages of bulk modification method make the present detection strategy promising for ultrasensitive detection of organic compounds. (C) 2014 Elsevier B.V. All rights reserved.

Platinum highly concave cubes with one leg on each vertex (hcclv) enclosed by {750} facets were conveniently synthesized for the first time through a one-pot solvothermal method in a mixed solvent of oleylamine and isopropanol containing platinum(ii) acetylacetonate. this method can also be extended to the synthesis of pt dendrite nanocubes at shorter reaction times. preferential overgrowth may facilitate the formation of pt hcclv in the presence of oleylamine and isopropanol. the pt hcclv exhibit excellent electrocatalytic activity for the oxidation of methanol (7.76x) and ethanol (5.46x) compared to commercial pt black. furthermore, the pt hcclv show higher stability than pt dendrite nanocubes and commercial pt black. the pt hcclv also remarkably improve the electrochemiluminescence activity of the luminol/h2o2 system.

Wireless electrochemiluminescence system based on the wireless energy transmission technique has been demonstrated for the first time. It has a disposable transmitter and a coiled energy receptor. The coiled energy receptor is smartly used as the electrode. The wireless electrochemiluminescence system has been used to detect hydrogen peroxide with good sensitivity, featuring advantages of easy manipulation, low cost, and small size. The handy and cheap wireless electrochemiluminescence device can use laptops as a power supply. It is promising for the development of portable or disposable electrochemiluminescence devices for various applications (e.g., such as point of care testing, field analysis, scientific research, and chemical education). These advantages enable one to integrate many wireless electrochemiluminescence minidevices with screen printing coiled electrode arrays in microwell plates and charge-coupled devices (CCD) cameras to develop electrochemiluminescence high-throughput screening systems with broad applications in clinical analysis, drug screening, and biomolecular interaction studies.

2,4,6-Trinitrotoluene (TNT) is a widely used nitroaromatic explosive with significant detrimental effects on the environment and human health. Its detection is of great importance. In this study, both electrochemiluminescence (ECL)-based detection of TNT through the formation of a TNT-amine complex and the detection of TNT through electrochemiluminescence resonance energy transfer (ECRET) are developed for the first time. 3-Aminopropyltriethoxysilane (APTES)-modified [Ru(phen)3](2+) (phen=1,10-phenanthroline)-doped silica nanoparticles (RuSiNPs) with uniform sizes of (73±3) nm were synthesized. TNT can interact with APTES-modified RuSiNPs through charge transfer from electron-rich amines in the RuSiNPs to the electron-deficient aromatic ring of TNT to form a red TNT-amine complex. The absorption spectrum of this complex overlaps with the ECL spectrum of the APTES-modified RuSiNPs/triethylamine system. As a result, ECL signals of the APTES-modified RuSiNPs/triethylamine system are turned off in the presence of TNT owing to resonance energy transfer from electrochemically excited RuSiNPs to the TNT-amine complex. This ECRET method has been successfully applied for the sensitive determination of TNT with a linear range from 1×10(-9) to 1×10(-6) M with a fast response time within 1 min. The limit of detection is 0.3 nM. The method exhibits good selectivity towards 2,4-dinitrotoluene, p-nitrotoluene, nitrobenzene, phenol, p-quinone, 8-hydroxyquinoline, p-phenylenediamine, K3[Fe(CN)6], Fe(3+), NO3(-), NO2(-), Cr(3+), Fe(2+), Pb(2+), SO3(2-), formaldehyde, oxalate, proline, and glycine.

Luminol electrochemiluminescence is dramatically increased by about five hundred times by taking full advantage of both electrochemical reduction and electrochemical oxidation using simple linear sweep voltammetry, leading to sensitive detection.

The reaction of hydrogen tetracholoroaurate, sodium borohydride and the diazonium compound prepared from 4-aminobenzoic acid results in the formation of gold nanocorals (Au-NCs) for the first time. Scanning electron microscopy images and transmission electron microscopy images show that the Au-NCs are composed of nanowires with a diameter of 5.3 nm. A glassy carbon electrode modified with Au-NCs is found to trigger intense electrochemiluminescence of the luminol/H2O2 system at a potential of −0.13 V. The effect was exploited to determine H2O2 in the 0.1 to 100 μM concentration range with a 30 nM detection limit.

Both the electrochemiluminescence (ECL) method for sensitive detection of ozone and the ECL resonance energy transfer (ECRET) using ozone have been reported for the first time. It is based on the ECRET of Ru(phen)3(2+)-doped silica nanoparticles (RuSiNPs) to indigo carmine. In the absence of ozone, the ECL of RuSiNPs is quenched as a result of the ECRET of RuSiNPs to indigo carmine. In the presence of ozone, the ECL of the system is "turned on" because ozone can oxidize indigo carmine and interrupt the ECRET from RuSiNPs to indigo carmine. In this way, it provides a simple ECL sensing of ozone via the proposed RuSiNP-based ECRET strategy with a linear range from 0.05-3.0 μM and a limit of detection (LOD) of 30 nM. The detection takes less than 5 min. This method is also successfully applied in the analysis of ozone in human serum samples and atmospheric samples.

We report that ammonium ion, as its organic amine counterparts, can be sensitively detected as a coreactant in the electrochemiluminescence (ECL) reaction of a novel iridium complex (pq)2Ir(N-phMA), where pq is 2-phenylquinoline anion and N-phMA is N-phenylmethacrylamide. The modified ECL electrode was fabricated by casting deposition of a homogeneous MWNTs/PVA/(pq)2Ir(N-phMA) dispersion solution onto the surface of a glassy carbon electrode. The electrode responds sensitively to ammonium ion in a wide concentration range. Two regression equations were established: Y = 0.7016X + 46.8 (R2 = 0.9985) and Y = 0.2565X + 174.2 (R2 = 0.9991) for the concentration from 1–180 nM and 180–1800 nM, respectively. The limit of detection was as low as 0.13 nM (S/N = 3).

Review: recent advances, novel phenomena, and prospectives in electrochemiluminescence; 198 refs.

Most electrochemiluminescence (ECL) systems require high concentrations of quencher to totally quench ECL. In this study, we found that ozone can quench tris(2,2'-bipyridyl)ruthenium(II) ECL using formaldehyde, methylglyoxal, or glyoxalate as co-reactants at a glassy carbon electrode with remarkable efficiencies even when the concentration of ozone is merely 0.25% of that of the co-reactant. The strongest quenching is observed with the tris(2,2'-bipyridyl)ruthenium(II)/formaldehyde ECL system. The tris(2,2'-bipyridyl)ruthenium(II)/formaldehyde ECL intensities decrease linearly with the ozone concentration over the range of 0.025-25 μM (r = 0.9947) with a limit of detection of 8 nM. The method is more sensitive and faster than most methods. It shows high selectivity in the presence of other ROS or oxidants and some metal ions, such as H2O2, ClO(-), Mg(2+), Ni(2+), etc. The method exhibits high recoveries for the detection of ozone in a ventilated photocopy room.

The great success of electrochemiluminescence (ECL) for in vitro diagnosis (IVD) and its promising potential in light-emitting devices greatly promote recent ECL studies. More than 45% of ECL articles were published after 2010, and the first international meeting on ECL was held in Italy in 2014. This critical review discusses recent vibrant developments in ECL, and highlights novel ECL phenomena, such as wireless ECL devices, bipolar electrode-based ECL, light-emitting electrochemical swimmers, upconversion ECL, ECL resonance energy transfer, thermoresponsive ECL, ECL using shape-controlled nanocrystals, and ECL as an ion-selective electrode photonic reporter, a paper-based microchip, and a self-powered microfluidic ECL platform. We also comment on the latest progress in bioassays, light-emitting devices and, the computational approach for the ECL mechanism study. Finally, perspectives and key challenges in the near future are addressed (198 references).

The quenching of electrochemiluminescence by single-walled carbon nanohorn has been demonstrated for the first time. Moreover, a sensitive, label-free, and signal-on electrochemiluminescence ATP aptasensor was developed using single-walled carbon nanohorn as both quencher and scaffold.

Ozone unexpectedly dramatically suppresses the electrochemiluminescence (ECL) of Ru(phen)3(2+)/glyoxal at an ozone/glyoxal ratio of less than 0.5%. Moreover, a sensitive, simple and fast ECL method for ozone detection is developed, with a detection time within 1 min and a limit of detection of 20 nM.