Electrochemiluminescence Signal Research Articles

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.

Detection of urokinase based on ECL resonance energy transfer between block copolymers encapsulated iridium complex and ReS2 nanosheets

The encapsulation of water insoluble iridium complex in SiO2 nanoparticles can be used to fabricate aqueous electrochemiluminescence (ECL) sensor, however, the ECL signal is greatly reduced. It is urgent to explore more suitable method to encapsulate iridium complex and improve its ECL efficiency. Pluronic block copolymers has good biocompatibility and high load capacity, which might be used to encapsulate iridium complex. In the present work, one kind of concentric nanospheres were assembled by encapsulating iridium complexes into block copolymers using poly (styrene-co-maleicanhydride) (PSMA@Ir). Strong anodic ECL signal was obtained at PSMA@Ir nanospheres modified electrode without additional coreactant. The light absorption character of ReS2 nanosheets (ReS2NS) endowed it the ability to accept energy from PSMA@Ir ECL. As a result, a novel ECL resonance energy transfer (ECL-RET) system was constructed with PSMA@Ir as energy donor while ReS2NS as energy acceptor. Based on the above results, an ECL aptasensor was designed to detect urokinase (UPA). The ECL intensity changed linearly with the logarithm of UPA concentration in the range of 1.0 × 10−16–1.0 × 10−12 mol/L with a detection limit of 2.95 × 10−17 mol/L. The prepared sensor owned high sensitivity and selectivity, and provided new avenue for the application of water insoluble iridium complex in ECL sensing.

Strategies and trends in the amplification of electrochemiluminescence signals for biosensing

This article offers a thorough summary of recent studies on the amplification of electrochemiluminescence (ECL) signals in biosensing applications using nanomaterials, enzymes, rolling circle amplifications (RCA), hybridization chain reaction (HCR), DNA-mediated amplification, and nanozymes. Recent developments on the influence of nanoparticles on ECL properties were covered in this review. Defect, valence state, shape, surface ligand, and the spatial distribution of the composition of the nanomaterial are examples of the microstructures of nanomaterials. The review aims to illustrate how the features of ECL signal amplification for biosensing are related to the microstructures of nanomaterials. It also discusses different enzymatic (allosteric and entrasteric) methods for amplifying ECL signals. Nucleic acids are suitable for the robust creation of nanostructures due to their programmed self-assembly and intrinsic diverse selective molecular recognition. By virtue of their distinctive structures and structural feature these are considered as promising candidates as ECL signal amplifiers.

Eu-doped chitosan carbon dot/dendritic silver nanostructure-based biosensor for BRAF detection in thyroid cancer exosome

In this work, a novel electrochemiluminescence (ECL) biosensor has been constructed with Eu-doped chitosan carbon dot (Eu: Cs dot) and dendritic silver nanostructure. Firstly, Eu: Cs dots were synthesized as ECL tags, which not only possessed exceptional electrochemical characters and intense luminescence, but also can reacted with H2O2 as co-reactant to generate ECL signal. Furthermore, dendritic silver nanostructure with conductive gel was successfully prepared as sensing interface. The dendritic silver nanostructure with conductive gel displayed the ideal conductivity, good electrochemical stability, which can enhance the ECL intensity of Eu: CS dots. Finally, BRAF V600E from thyroid cancer exosome in the clinic eluate can be captured and detected. The results indicated the relative association between BRAF V600E mutation and lymphatic metastasis, which can be used in assessing thyroid cancer progression for advancing clinical diagnosis applications.

An ultrasensitive solid-state electrochemiluminescence sensor based on Ni-MOF@Ru(bpy)32+ and Au NPs@TiO2 for determination of permethrin

The novel TiO2 and Ni-MOF materials were synthesized and utilized for the detection of permethrin (PET). A highly sensitive solid-state electrochemiluminescence (ECL) sensor was developed based on Ni-MOF@Ru(bpy)32+ and Au NPs@TiO2. In this sensing platform, Ru(bpy)32+-Tripropyl Amine (TPrA) was used as a luminescent signal, Ni-MOF acted as a carrier to carry more luminescent reagents Ru(bpy)32+. Au NPs acted as promoters facilitated electron transport and TiO2 could further enhance the luminescence intensity of the system by synergistical interaction with Au NPs. The possible mechanisms of signal amplification were investigated. The ECL intensity decreased significantly with increasing PET concentration, enabling the determination of PET amount through the observation of the change in ECL signal intensity (ΔI). Under optimal experimental conditions, the linear range of PET concentration from 1.0 × 10−11 mol L−1 to 1.0 × 10−6 mol L−1, with a detection limit of 3.3 × 10−12 mol L−1 (3S/N). This method was successfully applied to determine PET in various vegetable samples.

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.

Aptamer responsive DNA Functionalized hydrogels electrochemiluminescence biosensor for the detection of adenosine triphosphate

DNA hydrogel represents a noteworthy biomaterial. The preparation of biosensors by combining DNA hydrogel with electrochemiluminescence can simplify the modification process and raise the experimental efficiency. In this study, an electrochemiluminescence (ECL) biosensor based on DNA hydrogel was fabricated to detect adenosine triphosphate (ATP) simply and quickly. CdTe–Ru@SiO2 nanospheres capable of ECL resonance energy transfer (RET) were synthesized and encapsulated CdTe–Ru@SiO2 in the DNA hydrogel to provide strong and stable ECL signals. DNA hydrogel avoided the labeling of ECL signal molecules. The aptamer of ATP as the linker of the hydrogel for the specificity of ATP detection. The cross-linked structure of the aptamer and the polymer chains was opened by ATP, and then the decomposition of the DNA hydrogel initiated the escape of CdTe–Ru@SiO2 to generate an ECL signal. The designed biosensor detected ATP without too much modification and complex experimental steps on the electrode surface, with good specificity and stability, and a wide linear range. The detection range was 10–5000 nM, and the detection limit was 6.68 nM (S/N = 3). The combination of DNA hydrogel and ECL biosensor provided a new way for clinical detection of ATP and other biomolecule.

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

In this study, a novel europium dual-ligand metal-organic gel (Eu-D-MOGs) with high-efficient anodic annihilation electrochemiluminescence (ECL) was synthesized as an ECL emitter to construct a biosensor for ultrasensitive detection of microRNA-221 (miR-221). Impressively, compared to the ECL signal of europium single-ligand metal-organic gels (Eu-S-MOGs), the ECL signal of Eu-D-MOGs was significantly improved since the two organic ligands could jointly replace the H2O and coordinate with Eu3+, which could remarkably reduce the nonradiative vibrational energy transfer caused by the coordination between H2O and Eu3+ with a high coordination demand. In addition, Eu-D-MOGs could be electrochemically oxidized to Eu-D-MOGs•+ at 1.45 V and reduced to Eu-D-MOGs•- at 0.65 V to achieve effective annihilation of ECL, which overcame the side reaction brought by the remaining emitters at negative potential. This benefited from the annihilation ECL performance of the central ion Eu3+ caused by its redox in the electrochemical process. Furthermore, the annihilation ECL signal of Eu3+ could be improved by sensitizing Eu3+ via the antenna effect. In addition, combined with the improved rolling circle amplification-assisted strand displacement amplification strategy (RCA-SDA), a sensitive biosensor was constructed for the sensitive detection of miR-221 with a low detection limit of 5.12 aM and could be successfully applied for the detection of miR-221 in the lysate of cancer cells. This strategy offered a unique approach to synthesizing metal-organic gels as ECL emitters without a coreactant for the construction of ECL biosensing platforms in biomarker detection and disease diagnosis.

Coreactant-Free Zirconium Metal-Organic Framework with Dual Emission for Ratiometric Electrochemiluminescence Detection of HIV DNA.

Owing to the limitations of dual-signal luminescent materials and coreactants, constructing a ratiometric electrochemiluminescence (ECL) biosensor based on a single luminophore is a huge challenge. This work developed an excellent zirconium metal-organic framework (MOF) Zr-TBAPY as a single ECL luminophore, which simultaneously exhibited cathodic and anodic ECL without any additional coreactants. First, Zr-TBAPY was successfully prepared by a solvothermal method with 1,3,6,8-tetra(4-carboxyphenyl)pyrene (TBAPY) as the organic ligand and Zr4+ cluster as the metal node. The exploration of ECL mechanisms confirmed that the cathodic ECL of Zr-TBAPY originated from the pathway of reactive oxygen species (ROS) as the cathodic coreactant, which is generated by dissolved oxygen (O2), while the anodic ECL stemmed from the pathway of generated Zr-TBAPY radical itself as the anodic coreactant. Besides, N,N-diethylethylenediamine (DEDA) was developed as a regulator to ECL signals, which quenched the cathodic ECL and enhanced the anodic ECL, and the specific mechanisms of its dual action were also investigated. DEDA can act as the anodic coreactant while consuming the cathodic coreactant ROS. Therefore, the coreactant-free ratiometric ECL biosensor was skillfully constructed by combining the regulatory role of DEDA with the signal amplification reaction of catalytic hairpin assembly (CHA). The ECL biosensor realized the ultrasensitive ratio detection of HIV DNA. The linear range was 1 fM to 100 pM, and the limit of detection (LOD) was as low as 550 aM. The outstanding characteristic of Zr-TBAPY provided new thoughts for the development of ECL materials and developed a new way of fabricating the coreactant-free and single-luminophore ratiometric ECL platform.

MoS2/MXene Van der Waals heterojunction-based electrochemiluminescence sensor for triple negative breast cancer detection

The van der Waals heterojunction is able to combine the advantages of different materials and has potential to be used in biosensing researches. In this study, we developed a novel van der Waals heterojunction by combining MXene and MoS2 nanosheets for the electrochemiluminescence (ECL) sensing applications. This van der Waals heterojunction material not only possessed the superior conductivity of MXene, but also regulated the electron transport. Additionally, the incorporation of MoS2 nanosheets into the MXene interlayers significantly enhances the material stability. Meanwhile, nitrogen-rich quantum dots (N dots) were synthesized as ECL tags with an impressive nitrogen content of up to 75 %. By integrating the ECL response of N dots within the van der Waals heterojunction, we established a highly efficient sensing system for miRNA-373, which overexpressed in triple negative breast cancer tissues. The van der Waals heterojunction-based biosensor can enhance the ECL signal of N dots effectively to detect miRNA-373 from 1 fM to 1 μM. Consequently, the developed sensing system holds promise for the early detection of metastasis of the triple-negative breast cancer, paving the way for the effective clinical interventions.

Cu NCs@MXene-luminescent Faraday cage and Cu Nanocone/Bi NPs array-based saliva exosome assay for asthma evaluation

In this work, a novel nano-sensing system with luminescent Faraday cage mode has been developed to detect miRNA-221-5p in clinic saliva exosomes to evaluate asthma. Firstly, copper nanoclusters (Cu NCs) were synthesized in situ on the defects in Ti3CN nanosheets based on the nanoconfinement effect. Due to the Electronic metal-support interactions (EMSI) between MXene and the anchored Cu NCs, Cu NCs@MXene displayed the strong luminescence performance, high electrochemical activity and good stability properties. Furthermore, MXene nanosheets with good conductivity and flexibility was used to expand the outer Helmholtz plane and improve the sensing ability. Meanwhile, Cu nanocone/Bi nanoparticles (NPs) arrays were constructed by step-by-step electrodeposition. Due to the surface plasmon coupling effect, the Cu nanocone/Bi NPs arrays can convert the electrochemiluminescence (ECL) signal of Cu NCs@MXene-Faraday cage into the directional emission with 13.4-fold enhancement. Finally, a thin phospholipid film and capture DNA were modified on the surface of the Cu nanocone/Bi NPs array as the sensing interface to detect miRNA-221-5p in saliva exosomes. The designed nano-sensing system had a detection range was 1.0 × 10-16 ∼ 1.0 × 10-8 mol/L with the detection limit of 34 aM. Finally, the biosensor has been successfully employed to evaluate asthma in the clinical analysis.

Photoactivated Controlled Dnazyme Platform for on-Demand Activation Sensitive Electrochemiluminescence mRNA Analysis.

Programming ultrasensitive and stimuli-responsive DNAzyme-based probes holds great potential for on-demand biomarker detection. Here, an optically triggered DNAzyme platform was reported for on-demand activation-sensitive electrochemiluminescence (ECL) c-myc mRNA analysis. In this design, the sensing and recognition function of the split DNAzyme (SDz) probe was silent by engineering a blocking sequence containing a photocleavable linker (PC-linker) group at a defined site that could be indirectly cleaved by 302 nm ultraviolet (UV) light. When the SDz probes were assembled on the Au nanoparticles and potassium (K) element doped graphitic carbon nitride nanosheet (K-doped g-C3N4) covered electrode, UV light activation induces the configurational switching and consequently the formation of an active DNAzyme probe with the help of target c-myc mRNA, allowing the cleavage of the substrate strand by magnesium ions (Mg2+). Thus, the release of a ferrocene (Fc)-labeled DNAzyme 2 strand contributed to an extreme ECL signal recovery. In the meantime, the released target c-myc mRNA combined another inactive SDz motif to form active DNAzyme and repeat the cyclic cleavage reaction, resulting in the signal amplification. Furthermore, according to the responses toward two other designed nPC-SDz and m-SDz probes, we demonstrated that controlled UV light mediated photoactivation of the DNAzyme biosensor "on demand" effectively constrained the ECL signal to the mRNA of interest. Moreover, false positive signals could also be avoided due to such a photoactivation design with UV light. Therefore, this study provided a simple methodology that may be broadly applicable for investigating the mRNA-associated physiological events that were difficult to access using traditional DNAzyme probes.

An electrochemiluminescent dual-signal immunosensor based on a Ru(bpy)32+-doped silica nanoparticle/copper nanocluster composite for okadaic acid detection

In this study, a sensitive dual-signal electrochemiluminescence (ECL) immunosensor was developed for okadaic acid (OA) detection utilizing copper nanoclusters (CuNCs) and Ru(bpy)32+-doped silica nanoparticles (RuSiNPs). Interestingly, the CuNCs could simultaneously enhance both cathodic (−0.95 V) and anodic (+1.15 V) ECL signals of RuSiNPs, forming a dual-signal ECL sensing platform. Further, RuSiNPs@CuNCs were used as immunomarkers by covalently conjugating them with an anti-OA monoclonal antibody (mAb) to form probes. Finally, dual ECL signals of the immunosensor were fabricated and showed good linear relationships with OA concentrations in the range of 0.05–70 ng mL−1, having a median inhibitory concentration (IC50) of 1.972 ng mL−1 and a limit of detection of 0.039 ng mL−1. Moreover, the constant ratio of the cathodic and anodic ECL peaks achieved self-calibration of the detection signal and improved the reliability of the results. Finally, we successfully applied the ECL sensor to detect OA in spiked oyster samples.

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.

Magnetic N-doped carbon derived from mixed ligands MOF as effective electrochemiluminescence coreactor for performance enhancement of SARS-CoV-2 immunosensor

COVID-19 as an infectious disease with rapid transmission speed is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), so, early and accurate diagnostics of COVID-19 is quite challenging. In this work, the selective and sensitive self-enhanced ECL method to detect of SARS-CoV-2 protein was designed with magnetic N-doped carbon derived from dual-ligand metal-organic frameworks (MOF) (CoO@N–C) with the primary and tertiary amino groups as a novel coreactant that covalently combined with Ru(bpy)2(phen-NH2)2+ as electrochemiluminescence (ECL) emitter. Mixed-ligand strategy and selected nitrogen-containing ligands, 4,4′,4′′-((1,3,5-triazine-2,4,6-triyl) tris-(azanediyl)) tribenzoic acid (H3TATAB) with 2-aminoterephthalic acid (BDC-NH2) were used for synthesis of the proposed MOF. Also, magnetic CoO@N–C with high synergistically charge transfer kinetics and good stability can be used as an effective platform/coreactor on the ITO electrode which load more Ru-complex as signal producing compound and SARS-CoV-2 N protein antibody to increase the sensitivity of the immunosensor. Furthermore, (CoO@N–C) as coreactor improved the ECL signal of the Ru (II)-complex more than 2.1 folds compared to tripropylamine. In view of these competences, the novel “on-off” ECL biosensor performed with great stability and repeatability for detection of SARS-CoV-2 protein, which exhibited a broad linearity from 8 fg. mL−1 to 4 ng. mL−1 (6 order of magnitude) and an ultra-low limit of detection 1.6 fg. mL−1. Finally, this proposed method was successfully applied to detect of SARS-CoV-2 N protein in serum sample with satisfactory results, indicating the proposed immunosensor has the potential for quick analysis of SARS-CoV-2.

Solvent Regulation Induced Cathode Aggregation-Induced Electrochemiluminescence of Tetraphenylethylene Nanoaggregates for Ultrasensitive Zearalenone Analysis.

Zearalenone (ZEN) is an extremely hazardous chemical widely existing in cereals, and its high-sensitivity detection possesses significant significance to human health. Here, the cathodic aggregation-induced electrochemiluminescence (AIECL) performance of tetraphenylethylene nanoaggregates (TPE NAs) was modulated by solvent regulation, based on which an electrochemiluminescence (ECL) aptasensor was constructed for sensitive detection of ZEN. The aggregation state and AIECL of TPE NAs were directly and simply controlled by adjusting the type of organic solvent and the fraction of water, which solved the current shortcomings of low strength and weak stability of the cathode ECL signal for TPE. Impressively, in a tetrahydrofuran-water mixed solution (volume ratio, 6:4), the relative ECL efficiency of TPE NAs reached 16.03%, which was 9.2 times that in pure water conditions, and the maximum ECL spectral wavelength was obviously red-shifted to 617 nm. In addition, "H"-shape DNA structure-mediated dual-catalyzed hairpin self-assembly (H-D-CHA) with higher efficiency by the synergistic effect between the two CHA reactions was utilized to construct a sensitive ECL aptasensor for ZEN analysis with a low detection limit of 0.362 fg/mL. In conclusion, solvent regulation was a simple and efficient method for improving the performance of AIECL materials, and the proposed ECL aptasensor had great potential for ZEN monitoring in food safety.

Improvement on electrochemiluminescence properties of graphite carbon nitride by metal oxidation state regulation

AbstractReasonable design is of great significance for improving the performance of electrochemiluminescence (ECL) co‐reactant accelerators. The different d‐band structure of metal single atoms will produce different oxidation states, which may change the adsorption of reaction intermediates to the catalyst and affect its catalytic activity. In this study, we have demonstrated that the ECL performances of graphite carbon nitride (CN) can be promoted by modulating the metal oxidation states of co‐reaction accelerator for the first time. The oxidation states of Au were modulated by the different electronic metal–support interaction (EMSI) between the co‐reaction accelerator (Au single atoms, Au nanoparticles [Au NPs]) and CN, and the effects of Au oxidation states on the ECL performances of CN were investigated. Comparison to pristine CN and CN nanosheets supported Au nanoparticles (Au NPs/CN), stronger and more stable ECL intensity of CN nanosheets supported Au single‐atoms (AuS/CN) was obtained. The ECL signal of AuS/CN was about 32.2 times that of the original CN, and 2.8 times that of Au NPs/CN in the same Au loading content (0.8%). Detailed mechanism revealed that AuS/CN with higher Au oxidation state has better conductivity and stronger catalytic activity, which promotes the electric reduction of CN and S2O82−, increases the lifetime of the excited state CN*, and significantly improves the ECL performance of CN. In addition, this work provides a detailed understanding of the essence of EMSI for the ECL intensity amplification and established a feasible method for the improvement of ECL capacities of co‐reactant accelerators.

An AuNPs/Co3O4 nanocubic cage–based electrochemiluminescent immunosensor for Corin: A biomarker of stroke

Stroke, or cerebral apoplexy, is a paroxysmal disease that seriously threatens the neurological functions of middle-aged and older men, resulting in high rates of disability and mortality. The blood level of Corin can accurately predict the risk and subtype of stroke. Herein, an immunosensor was developed utilizing a nanocomposite of Au nanoparticles and Co3O4 nanocubic cages (AuNPs/Co3O4NcC) as the sensing substrate, with luminol serving as the sensing probe for Corin detection. Through the application of 3-aminopropyltrimethoxysilane, AuNPs/Co3O4NcC was affixed to the surface of indium tin oxide (ITO)-coated glass, considerably enhancing the electrochemiluminescence (ECL) performance of luminol due to its peroxidase-like activity. To confer biological specificity by immobilizing the Corin antibody on this substrate and to block residual active sites with bovine serum albumin, an immunosensor was developed. The capture of Corin protein by the antibody through an immune reaction, leading to its binding on the sensor, resulted in a decreased ECL signal. Under optimized conditions, the proposed ECL immunosensor demonstrated a broad linear response range from 1 pg/mL to 4800 pg/mL and a low detection limit of 0.26 pg/mL. This ECL immunosensor is characterized by its specificity, stability, and reproducibility and can detect Corin in real blood samples.

Microfluidic Immunosensor Platform for Sensitive Detection of Human Epidermal Growth Factor Receptor-2 Based on Enhanced Cathode Electrochemiluminescence of Bimetallic Nanoclusters.

In this work, a microfluidic immunosensor chip was developed by incorporating microfluidic technology with electrochemiluminescence (ECL) for sensitive detection of human epidermal growth factor receptor-2 (HER2). The immunosensor chip can achieve robust reproducibility in mass production by integrating multiple detection units in a series. Notably, nanoscale materials can be better adapted to microfluidic systems, greatly enhancing the accuracy of the immunosensor chip. Ag@Au NCs closed by glutathione (GSH) were introduced in the ECL microfluidic immunosensor system with excellent and stable ECL performance. The synthesized CeO2-Au was applied as a coreaction promoter in the ECL signal amplification system, which made the result of HER2 detection more reliable. In addition, the designed microfluidic immunosensor chip integrated the biosensing system into a microchip, realizing rapid and accurate detection of HER2 by its high throughput and low usage. The developed short peptide ligand NARKFKG (NRK) achieved an effective connection between the antibody and nanocarrier for improving the detection efficiency of the sensor. The immunosensor chip had better storage stability and sensitivity than traditional detection methods, with a wide detection range from 10 fg·mL-1 to 100 ng·mL-1 and a low detection limit (LOD) of 3.29 fg·mL-1. In general, a microfluidic immunosensor platform was successfully constructed, providing a new idea for breast cancer (BC) clinical detection.

Multiple signal-enhanced electrochemiluminescence aptamer sensors based on carboxylated ruthenium (II) complexes for acetamiprid detection

BackgroundRapid and sensitive detection for acetamiprid, a kind of widely used neonicotinoid insecticide, is very meaningful for the development of modern agriculture and the protection of human health. Highly stable electrochemiluminescence (ECL) materials are one of the key factors in ECL sensing technology. ECL materials prepared by porous materials (e.g., MOFs) coated with chromophores have been used for ECL sensing detection, but these materials have poor stability because the chromophores escape when they are in aqueous solution. Therefore, the development of highly stable ECL materials is of great significance to improve the sensitivity of ECL sensing technology. ResultsIn this work, by combining etched metal-organic frameworks (E-UIO-66-NH2) as carrier with Tris(4,4′-dicarboxylic acid-2,2′-bipyridine)Ru(II) chloride (Ru(dcbpy)32+) as signal probe via amide bonds, highly stable nanocomposites (E-UIO-66-NH2-Ru) with excellent ECL performance were firstly prepared. Then, using MoS2 loaded with AuNPs as substrate material and co-reactant promoter, a signal off-on-off ECL aptamer sensor was prepared for sensitive detection of acetamiprid. Due to the excellent catalytic activity of E-UIO-66-NH2-Ru and MoS2@Au towards K2S2O8, the ECL signals can be enhanced by multiple signal enhancement pathways, the prepared ECL aptamer sensor could achieve sensitive detection of acetamiprid in the linear range of 10−13 to10−7 mol L−1, with the limit of detection (LOD) of 2.78ⅹ10−15 mol L−1 (S/N = 3). After the evaluation of actual sample testing, this sensing platform was proven to be an effective method for the detection of acetamiprid in food and agricultural products. Significance and noveltyThe E-UIO-66-NH2-Ru prepared by linking Ru(dcbpy)32+ to E-UIO-66-NH2 via amide bonding has very high stability. The synergistic catalytic effect of MoS2 and AuNPs enhanced the ECL signal. By exploring the sensing mechanism and evaluating the actual sample tests, the proposed signal "on-off" ECL sensing strategy was proved to be an effective and excellent ECL sensing method for sensitive and stable detection of acetamiprid.