ECL Signal Research Articles

Self-enhanced electrochemiluminescence of luminol induced by palladium–graphene oxide for ultrasensitive detection of aflatoxin B1 in food samples

In this work, a novel and credible electrochemiluminescence immunoassay (ECLIA) was constructed for the ultrasensitive and highly selective detection of aflatoxin B1 (AFB1). Amino-functionalized 3D graphene hydrogel (NGH) served as the ECL platform with the self-enhanced ECL of luminol–palladium–graphene oxide (lum–Pd–GO) acting as a marker for the antibodies against AFB1. Pd–GO was synthesized by a self-redox method; it promotes the formation of reactive oxygen species, which are important to the ECL of luminol, from dissolved oxygen. The π–π conjunction between luminol and GO shortens their electron transfer distance, resulting in an amplified ECL signal (∼8.5 times larger than conventional luminol ECL). Moreover, 3D NGH, with its good conductivity, large surface area, and sufficient amino groups, was used to anchor gold nanoparticles (AuNPs), which subsequently immobilized bovine serum albumin (BSA)–AFB1 through Au–S bonds. The resultant, competitive ECLIA gave a relative low detection limit of 5 × 10−3 μg kg−1 and exhibited a broad linear relationship over the range of 0.05–50 μg kg−1. Finally, the proposed ECLIA was successfully used to analyze AFB1 contents in food samples. ECLIA: electrochemiluminescence immunoassay; AFs: Aflatoxins; HPLC: high-performance liquid chromatography.

A signal amplification of near-infrared electrochemiluminescence immunosensor for SFTSV determination based on SiO2 photonic crystals nanomembrane

In this work, a novel near-infrared electrochemiluminescence signal amplification strategy was fabricated based on SiO2 photonic crystals nanomembrane as the ECL electrodes for sensitive and specific detection of SFTSV. The photonic crystal structure of the SiO2 nanomembrane has an excellent light scattering effect, which significantly increases the photon flux in the luminescent molecule and improves the excitation of the ECL molecule (CdTe@CdS QDs) by the re-radiation dipole electromagnetic field. In addition, the increase of the effective electroactive area of the photonic crystals modified electrode also prominently contributes to the ECL intensity. The results manifested that the SiO2 photonic crystals nanomembrane modified electrode constructed in this work can effectively improve the ECL intensity by about 7 times. Subsequently, a sandwich-type SFTSV immunosensor with a very low limit of detection of 0.0014 fg/mL was constructed. Due to the low cost and easy preparation of SiO2 photonic crystal solid-state electrodes, this work can not only effectively detect the SFTSV virus, but also provides an effective ECL signal amplification strategy.

Hybridization chain reaction circuit-based electrochemiluminescent biosensor for SARS-cov-2 RdRp gene assay.

In this work, we designed an ECL ratiometric biosensor with a three-stranded Y-type DNA (Y-DNA) probe and induced a hybridization chain reaction (HCR) for the highly sensitive detection of SARS-CoV-2 nucleic acid. The important component of this system is the self-assembled Y-Shaped probe based on three nucleic acids. Y1, Y2, and Y3 can be linked by complementary base pairing to Hairpin1 (H1), Hairpin2 (H2), and Ru modified DNA (Ru1), respectively. H1 and H2 can trigger the HCR reaction when activated by the SARS-CoV-2 RdRp gene and the 5′ end of Ru1. The 5′ end of Ru1 is modified with the Ru complex, which can produce a strong electrochemiluminescence luminescence signal at 620 nm under an applied voltage. Through the amplification of Y-DNA-induced HCR reaction, Ru1 on the electrode surface gradually increased, the ECL signal at 460 nm was gradually quenched, and the signal at 620 nm was steadily generated. The SARS-CoV-2 RdRp gene can be quantified according to the degree of decrease of ECL signal at 460 nm and the increase of ECL signal at 620 nm. Combining the two signal amplification strategies, this ratiometric ECL biosensor can accurately and efficiently detect the target gene with a detection limit of 59 aM.

Electrogenerated chemiluminescence sensor for silver ions based on their coordination interaction with cucurbit[6]uril

Strong luminol ECL was obtained at the Q[6]/GCE. The interaction between Ag+ and Q[6] could decrease ECL signal. An ECL sensor for the detection of Ag+ was proposed based on the competitive interaction between luminol, silver ions and Q[6].

Plasmon-Boosted Cu-Doped TiO2 Oxygen Vacancy-Rich Luminol Electrochemiluminescence for Highly Sensitive Detection of Alkaline Phosphatase.

In this study, an effective oxygen vacancy (Ov)-involved luminol-dissolved oxygen (O2) electrochemiluminescence (luminol-DO ECL) system was developed and exploited for ECL sensing applications through significant plasmon enhancement of the Ov-involved weak luminol-DO ECL signals by the combined use of Cu-doped TiO2 oxygen vacancy and a Au@SiO2 nanomembrane. The results disclosed that the ECL response of the corresponding system could be synergistically boosted, and the plausible underlying mechanism has been discussed. Furthermore, for the first time, the developed system has been successfully applied for the highly sensitive detection of alkaline phosphatase with a low limit of detection of 0.005 U/L, with an excellent linear range from 0.005 to 10 U/L, as well as good stability and reproducibility.

An electrochemiluminescence biosensor for cadmium ion based on target-induced strand displacement amplification and magnetic Fe3O4-GO nanosheets

Taking advantage of an exquisite hairpin DNA for strand displacement amplification (SDA) and the magnetic Fe3O4-graphene oxide nanosheets (MGN) as the carrier, an immobilization-free ECL biosensor was constructed for ultra-trace detection of Cd2+. Firstly, the ECL probe Ru (phen)32+ easily diffuses in the solution and reaches the electrode surface to induce strong ECL signal. This is because the pre-designed hairpin DNA is constrained by MGN in the absence of Cd2+. The presence of Cd2+ releases cDNA by binding to its corresponding aptamer, leading to removal of hairpin DNA away from the surface of MGN. In this case, SDA amplification was evoked and generated numerous dsDNA which further trapped Ru (phen)32+ in its groove. It is difficult for the embedded ECL probe to touch the electrode surface to generate ECL signal. Therefore, the concentration of Cd2+ was monitored according to the attenuation of ECL signal. This method showed high sensitivity to Cd2+ with a detection limit of 1.1 × 10−4 ppb. Moreover, it not only avoids many condition optimizations required in the conventional SDA method, but also circumvent the modification and immobilization of DNA probe. This sensor is further applied in the detection of Cd2+ in the sample of traditional Chinese medicine.

Ultrasensitive dual-quenching electrochemiluminescence immunosensor for prostate specific antigen detection based on graphitic carbon nitride quantum dots as an emitter.

Early monitoring of prostate-specific antigen (PSA) is crucial in diagnosis and proactive treatment of prostate disease. Herein, a dual-quenching ternary ECL immunosensor was designed for PSA detection based on graphitic carbon nitride quantum dots (g-CNQDs, as an emitter), potassium persulfate (K2S2O8, as a coreactant), and silver nanoparticles doped multilayer Ti3C2 MXene hybrids (Ag@TCM, as a coreaction accelerator). First, Ag@TCM was immobilized on the surface of a glassy carbon electrode, then g-CNQDs was further adsorbed on Ag@TCM to acquire a higher initial ECL signal at a potential window from - 1.3 to 0.0V (vs. Ag/AgCl). Ag@TCM not only acted as the coreaction accelerator, but also as a matrix to load enormous g-CNQDs and prostate-specific capture antibody via Ag-N bond. Meanwhile, prostate-specific detection antibody was marked by gold nanoparticles modified manganese dioxide as a dual-quenching probe (Ab2- Au@MnO2). When Ab2-Au@MnO2 was introduced into the ternary ECL system via sandwiched immuno-reaction, the high-sensitive detection of PSA was achieved by the dual-quenching effect, caused by the resonant energy transfer from g-CNQDs (energy donor) to Au@MnO2 (energy acceptor). As a result, this ECL immunosensor showed a good dynamic concentration range from 10fg·mL-1 to 100ng·mL-1 with a detection limit of 6.9fg·mL-1 for PSA detection. The dual-quenching ECL strategy presented high stability and good specificity to open up a new pathway for ultrasensitive immunoassay.

A visual electrochemiluminescence molecularly imprinted sensor with Ag+@UiO-66-NH2 decorated CsPbBr3 perovskite based on smartphone for point-of-care detection of nitrofurazone

An efficient, portable and sensitive electrochemiluminescence molecularly imprinted polymer (ECL-MIP) sensor with CsPbBr3 perovskite nanomaterials (NMs) was developed based on a smartphone point-of-care testing (POCT) system. In this system, a rechargeable lithium-ion battery served as the power supply, and Ag+@UiO-66-NH2/CsPbBr3 was regarded as an ECL emitter, while the ECL signal was read-out using a smartphone. The optimal functional monomer (pyrrole) was screened by density functional theory (DFT), and then the MIP membrane was formed by the electrochemical polymerization method with template molecule (nitrofurazone, NFZ). The luminescence images were collected by the smartphone camera and the image color was analyzed by self-designed software, and the embedded artificial neural network-assisted machine learning was used for automatic analysis. Under the optimal experimental conditions, the ECL signal responded linearly to NFZ in the range of 0.5 nM ∼ 100 μM, with the detection limit of 0.09 nM. Overall, the obtained sensor exhibited good sensitivity, desirable selectivity, and favorable stability in response to NFZ. The developed smartphone-based ECL-MIP system with the portable device provided an alternative strategy for the point-of-care monitoring of biochemical analytes.

Competitive electrochemiluminescence aptasensor based on the Ru(II) derivative utilizing intramolecular ECL emission for E2 detection

One competitive aptasensor based on novel intramolecular ECL emission system was investigated for ultrasensitive detection of E2. It should be noted that the Ru(II) derivative for the mechanism of intramolecular ECL could improve electron transfer efficiency and reduce energy consumption. The Ru(II) derivatives were prepared by optimizing distribution ratio of Ru(dcbpy)32+ and carbohydrazide for acquiring the ECL signal maximum. Stimulated by In3+/In+ redox reversible electron pair in the InVO4/β-AgVO3 heterostructures, the InVO4/β-AgVO3 heterostructures were designed as co-reaction accelerator to expedite ECL emission reaction between CON4H6• and Ru(dcbpy)33+. Taking advantage of associative competition between cDNA and E2 with aptamer, the ECL signal realized further amplification. The specific binding of the aptamer to E2, was stronger than that to the cDNA by hybridization. A mass of Ru(II) derivatives could adsorb and embed into the hybridized double-stranded DNA to immobilize on the electrode surface and generate satisfactory ECL signal. The specific binding of the aptamer to E2 decreased the cDNA content on electrode surface, which contributed to lessen the adsorption amount of Ru(dcbpy)32+ and distinctly affected the ECL signal. Under optimal conditions, the proposed biosensor provided an admirable linearity to the level of E2 between 0.001 nmol/L and 100 nmol/L with a low detection limit of 0.27 pmol/L. The proposed aptasensor not only stimulates more interest in the mechanism of intramolecular ECL but also has towardly development potential for constructing competitive strategies.

Electrochemiluminescence Biosensor Based on Entropy-Driven Amplification and a Tetrahedral DNA Nanostructure for miRNA-133a Detection.

The early and rapid diagnosis of acute myocardial infarction (AMI) is of great significance to its treatment. Here, we developed an electrochemiluminescence biosensor based on an entropy-driven strand displacement reaction (ETSD) and a tetrahedral DNA nanostructure (TDN) for the detection of the potential AMI biomarker microRNA-133a. In the presence of the target, numerous Ru(bpy)32+-labeled signal probes (SP) were released from the preformed three-strand complexes through the process of ETSD. The ETSD reaction cycle greatly amplified the input signal of the target. The released SP could be captured by the TDN-engineered biosensing interface to generate a strong ECL signal. The rigid structure of TDN could significantly improve the hybridization efficiency. With the assistant of double amplification of TDN and ETSD, the developed biosensor has a good linear response ranging from 1 fM to 1 nM for microRNA-133a, and the detection limit is 0.33 fM. Additionally, the constructed biosensor has excellent repeatability and selectivity, demonstrating that the biosensor possesses a great application prospect in clinical diagnosis.

Integrated heterojunction and photothermal effect multiple enhanced ratiometric electrochemiluminescence immunosensor based on calcination controlled and tunable TiO2 mesocrystals

Stratifin (SFN) is considered to be a new biomarker of cancers. In clinical medicine, combining tissue chip technology and immunohistochemical methods qualitatively prove that the abnormal expression of SFN is related to cancer. However, the quantitative detection of SFN is rarely performed. Herein, an ultrasensitive ratiometric ECL immunosensor was constructed to realize SFN determination. A polyvinylpyrrolidone (PVP)-assisted synthesis of TiO2 (PVP-TiO2)@Poly[(9,9-dioctyfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadia-zol-4,8-diyl)] (PFBT) nanomaterial with anodic ECL signal and carbon-coated TiO2 (C-TiO2)-loaded graphitic carbon nitride quantum dots (g-C3N4 QDs) with cathodic ECL signal were firstly used as a pair of luminophores to generate two potential-resolved ECL signals. PVP-TiO2 provided a substrate for the immobilization of biomolecules. C-TiO2 due to the high specific surface area loaded a large amount of g-C3N4 QDs, thereby increasing the ECL intensity. Not only that, the heterojunction formed by semiconductors could also further enhance ECL signal. Impressively, PFBT-C-TiO2 conjugation possessed outstanding photothermal property, which could serve as photothermal convertor device and accelerate the electrochemical mass transfer on the electrode surface, further amplified ECL signal. The ratiometric biosensor showed good linear response for SFN from 10−6ng mL–1 to 0.1 ng mL–1 with a detection limit of 0.33 fg mL–1.

A DNAzyme-Based Dual-Stimuli Responsive Electrochemiluminescence Resonance Energy Transfer Platform for Ultrasensitive Anatoxin-a Detection.

An effective and precise electrochemiluminescence resonance energy transfer (ECL-RET), including the efficient regulation over the proximity of a donor and an acceptor and the reliable stimuli responsive as well as the avoidance of undesirable probes leakage, etc., is significant for the development of an accurate and sensitive ECL detection method; yet, the current literature in documentation involves only a limited range of such ECL-RET systems. Herein, we propose an ECL-RET strategy with dually quenched ultralow background signals and a dual-stimuli responsive, accurate signal output for the ultrasensitive and reliable detection of anatoxin-a (ATX-a). The dual quenching is accomplished by an integrated ECL-RET probe of metal organic frameworks (MOFs) encapsulated into Ru(bpy)32+ (Ru-MOF) (donor) coated with silver nanoparticles (AgNPs) shell (acceptor 1) and close proximity with DNA-ferrocene (Fc) (acceptor 2). Multistimuli responsive DNAzyme facilitated the accurate signal switch by both target ATX-a and hydrogen peroxide (H2O2). Because of the specific recognition of the aptamer toward ATX-a, an intricate design of the DNA sequence enabled the exposure of the Ag+-dependent DNAzyme sequence and H2O2 in situ generated Ag+ triggering a catalytic cleavage reaction to freely release the two ECL-RET energy acceptors, thus switching the ECL signal significantly and achieving ultrasensitive detection. It is noteworthy that AgNPs are key in this ECL-RET strategy, serving both as the gate-keepers for avoiding ECL probes leakage and also the ECL energy acceptors, and mostly importantly serving as the redox substrate for the subsequent DNAzyme catalytic signal switch. The proposed ECL-RET aptasensor for ATX-a detection displayed splendid monitoring performance with a quite low detection limit of 0.00034 mg mL-1. This sensor not only led to the development of a dual-quenching ECL-RET system but also provided meaningful multistimuli responsive ECL biosensing platform construction, which shows a promising application prospect in complicated sample analysis.

Ratiometric electrochemiluminescence biosensor based on Ir nanorods and CdS quantum dots for the detection of organophosphorus pesticides

The poor solubility and limited ECL emission efficiency of iridium (Ir) complexes in aqueous restricted their application in ECL field. This work prepared water-soluble Ir nanorods (Ir NRs) via carboxyl-functionalizing tris (2-phenylpyridine) iridium(Ⅲ) (Ir(ppy)3) using poly(styrene-co-maleicanhydride) (PSMA) and further developed a highly sensitive dual-signal nanoprobe with Ir NRs as anodic emitter and CdS quantum dots (QDs) as cathodic emitter. Ir [email protected] QDs served as the matrix to immobilize enzymes to construct an ECL ratio biosensor for detecting organophosphorus pesticides (OPs). The dual-functional H2O2 produced by enzymatic reaction had an opposite effect on two ECL signals, namely enhanced the cathodic signal and quenched the anodic signal. With the OPs, the activity of enzyme was inhibited and the generation of H2O2 was prevented, thus the opposite changes of two ECL signals were detected. The detection of ethyl paraoxon (EP) as target OPs was achieved with a linear range from 5.0 × 10−12 to 5.0 × 10−8 M and detection limit was 1.67 × 10−12 M. The excellent solubility and high ECL efficiency of Ir NRs in aqueous greatly expanded the application of Ir(Ⅲ) complexes. The opposite effect of H2O2 on two emissions of Ir [email protected] QDs provided a novel ratio ECL platform for bioanalysis.

Dual-quenching electrochemiluminescence resonance energy transfer system from IRMOF-3 coreaction accelerator enriched nitrogen-doped GQDs to ZnO@Au for sensitive detection of procalcitonin

Herein a novel electrochemiluminescence resonance energy transfer (ECL-RET) pair of isoreticular metal organic framework-3 (IRMOF-3) enriched nitrogen-doped graphene quantum dots (N-GQDs) luminescent material (N-GQDs@IRMOF-3@N-GQDs, donor) and Au nanoparticles modified zinc oxide nanorod (ZnO@Au, acceptor) were firstly designed to fabricate a dual-quenching sandwich-type ECL immunosensor for ultrasensitive analysis of procalcitonin (PCT). IRMOF-3 not only acted as a carrier for abundantly enriching luminescent N-GQDs by internal encapsulation and external decoration, but also a coreaction accelerator which could boost the transformation of persulfate ion S2O82− to generate more anion radical SO4−, so as to promote the ECL emission of N-GQDs. Additionally, Au nanoparticles were loaded onto the ZnO nanorods through in-situ modification to obtain ZnO@Au, which was firstly applied as a dual-quencher of ECL signal. In the best test environment, a wide detection range from 0.0001 to 100 ng mL−1 was obtained and the limit of detection is 12.58 fg mL−1 (S/N = 3). With excellent reproducibility and sensitivity, the practical test consequence of PCT in human serum samples was satisfactory. These results suggested that this sensing system could provide a reference model for effective detection of disease markers in clinical medicine.

Simultaneous detection of Vitamin B12 and Vitamin C from real samples using miniaturized laser-induced graphene based electrochemiluminescence device with closed bipolar electrode

Herein, a two and three-channel laser-induced graphene (LIG) based closed bipolar Electrochemiluminescence (LIG-C-BPE-ECL) system was developed for sensing various analytes. Polyimide sheet was extensively used to fabricate two and three-channel LIG-C-BPE-ECL device as it has the ability to produce graphitized zones in a single step. CO2 infrared laser, with optimized parameters, was effectively used to fabricate closed bipolar (C-BPE) and driving electrodes (DEs). A miniaturized portable 3D printed system was developed to hold the device and place the smartphone to create a standalone ECL sensing platform. The smartphone not only captured the ECL signal but also powered the ECL device through DC to DC buck-boost converter. Two and three-channel LIG-C-BPE-ECL device was fabricated for the sensing of both individual and two analytes at the same time. The performance of the two-channel LIG-C-BPE-ECL device was validated by doing individual sensing of Hydrogen peroxide (H2O2), Vitamin B12 and Vitamin C for the linear range of 0.5–100 μM, 0.5–1000 nM and 1–1000 μM with a limit of detection (LOD) 0.303 μM, 0.109 nM and 0.96 μM respectively. Subsequently, three-channel LIG-C-BPE-ECL device was fabricated and simultaneous detection of Vitamin B12 and Vitamin C was accomplished. Finally, real sample analysis has been performed by doing concurrent sensing of vitamin B12 and vitamin C using three-channel LIG-C-BPE-ECL device with a good recovery rate. Such a miniaturized portable LIG-C-BPE-ECL system has great potential to be used in various applications including point of care testing.

Electrochemical stripping chemiluminescent sensor based on copper nanoclusters for detection of carcinoembryonic antigen

As a new type of nano-catalytic material, copper nanoclusters (Cu NCs) have received more and more attention in various fields such as biosensors and catalysis. In this work, an electrochemical stripping chemiluminescent (ESCL) aptamer sensor based on Cu NCs was constructed for the detection of carcinoembryonic antigen (CEA). The Cu NCs were generated using DNA duplex (the CEA aptamer and its complementary strand) as template. During the ESCL detection process, Cu NCs catalyzed the reduction of H2O2 and were gradually electrochemically oxidized to Cu2+, which both promoted the decomposition of H2O2 and thus greatly improved the ECL of luminol. CEA could specifically bind with its aptamer, so the DNA duplex was damaged, causing a decrease of Cu NCs and lower ECL signals. Under the optimized conditions, the sensor achieved a high sensitivity detection of CEA with a linear range of 0.2 fg mL−1 to 1 ng mL−1 and a detection limit of 66.67 ag mL−1 (S/N = 3). In addition, the sensor exhibited good specificity, stability and reproducibility, and the detection of actual samples obtained satisfactory results, indicating that the provided strategy has potential application prospects in clinical detection.

A whispering gallery mode-based surface enhanced electrochemiluminescence biosensor using biomimetic antireflective nanostructure

In this work, we developed a whispering gallery mode-based surface enhanced electrochemiluminescence (SE-ECL) sensing system with strong electromagnetic field strength. Ni doped MoS2 QDs were synthesized as a novel ECL emitter which can effectively catalyze coreactant and generate strong ECL signal. Au NPs were electrodeposited on the surface of MoS2 nanosheets to construct biomimetic antireflective nanostructure. And SiO2 dielectric microspheres with the whispering gallery mode characteristic were placed on the top of Au NPs/MoS2 nanosheets. The optoplasmonic hybrid structures can efficiently enhance the localization electric field and couple hot spot area. Therefore, the ECL intensity has been amplified as 10 times stronger compared to the original Ni doped MoS2 QDs. This sandwich type SE-ECL sensor can quantify K-RAS gene in 1 fM to 1 nM concentration range with the detection limit as 0.3 fM.

Bipolar electrode ratiometric electrochemiluminescence biosensing analysis based on boron nitride quantum dots and biological release system

In this article, we developed a novel ECL ratiometry on a closed bipolar electrode (BPE) for the sensitively and accurately detection of miRNA-21. High quantum yield and low toxicity BNQDs was synthesized and coated at BPE cathode as an ECL emitter, while the anode of BPE was calibrated via another ECL material, Ir(df-ppy)2(pic) (Firpic). The electron neutrality at both ends of the BPE electrically coupled the reactions on each pole of the BPE. Therefore, one electrochemical sensing reaction could be quantified at one end of the BPE. By the hybridization of target miRNA-21 and hairpin, the glucose blocked in MSNs by the hairpin was released and reacted with glucose oxidase (GOD) to generate H2O2, thereby reducing the ECL signal of the cathode BNQDs/K2S2O8 system and promoting ECL signal of anode Firpic/TPrA. Further, the G-quadruplex formed by unreacted hairpin bases consumed H2O2, which not only recovered the ECL of BNQDs, but also further improved the ECL emission of Firpic. Therefore, the concentration of miRNA-21 could be measured by the ECL ratio of BNQDs and Firpic. The data showed that the detection limit was 10−15 M (S/N = 3) with the linear range of 10−15 M to 10−9 M. The strategy of the BPE-ECL ratio method based on BNQDs showed a good prospect in clinical application.

Bimodal Electrogenerated Chemiluminescence of the Luminol/Dicyclohexylamine (DCHA) System: A Novel and Highly Sensitive Detection of DCHA via ECL-Flow Injection Analysis.

Though luminol is one of the most prominent and extensively studied luminophores in ECL studies, only H2O2 has been widely used as a co-reactant. This limits the variety of applications because of the short-time radical stability and low quantum efficiency. In the present work, we identified dicyclohexylamine (DCHA) as a new and highly efficient anodic co-reactant in ECL for the luminol molecule. The electrochemical and ECL behavior of the luminol/DCHA system was studied on a simple bare GCE surface, which results in two anodic ECL peaks at the potential region of +0.38 and +0.94 V vs Ag/AgCl. The evidence of (DCHA•+) and O2•- generated in the system was detected via flat-cell electron spin resonance (ESR) spectroscopy experiments at ∼20 °C. Using the bimodal ECL system, the highly sensitive detection of luminol was achieved with the detection limit down to 1.5 pM. Further, a homebuilt electrochemiluminescent detector coupled with a flow injection analysis (ECL-FIA) system was adopted to detect the DCHA contaminant in harvested honey, which achieved higher detection and sensitivity under the optimized experimental conditions. DCHA was detected in the range of 10 nM to 100 μM with the detection limit of 2 nM (S/N = 3). The present findings of new luminol/DCHA ECL signals produced a strong ECL emission, which leads to a greater potential to meet the fast-developing analytical application of a luminol-based ECL system.

Co-reactant-free self-enhanced solid-state electrochemiluminescence platform based on polyluminol-gold nanocomposite for signal-on detection of mercury ion

Development of a self-enhanced solid-state ECL platform creates a straightforward experimental design for the fabrication of point-of-care applications. Herein, we develop a promising method for self-enhanced solid-state ECL platform of polyluminol gold nanocomposite on glassy carbon electrode [(PL-Au)nano/GCE] via simple one-step electrochemical deposition process without involving any additional co-reactants. The presence of gold nanoparticles (AuNPs) augments the electron transfer kinetics of PL (polyluminol) and enhances the solid-state ECL intensity and promotes label-free, excellent sensitivity, and selectivity to detect Hg2+ in physiological pH through signal-on mode. Unlike pristine PL/GCE, electrochemically co-deposited AuNPs in the (PL-Au)nano/GCE composite, enable the co-reactant accelerator by improving the catalytic activity of PL towards oxygen reduction reaction (ORR) yielding in-situ ROS (co-reactant) generation. Further, the ECL intensity of (PL-Au)nano/GCE composite, gradually increases with each addition of Hg2+ ion. This is because of the formation of an amalgamation of Au-Hg on (PL-Au)nano/GCE composite surface which further accelerates the yield of in-situ ROS and enhances the intensity of ECL. Whereas no ECL signals changes were observed for PL/GCE composite. The proposed self-enhanced solid-state ECL platform is selectively sensing the Hg2+ ion in the linear range of 0.3–200 nM with a detection limit of 0.1 nM. The demonstrated (PL-Au)nano/GCE platform might pave new avenues for further studies in the solid-state ECL platform which could be more useful in on-site monitoring of clinical bioassay and immunosensors.