Cathodic electrochemiluminescence behavior of norfloxacin/peroxydisulfate system in purely aqueous solution

A signal-on electrochemiluminescence biosensor for detecting Con A using phenoxy dextran-graphite-like carbon nitride as signal probe

A novel signal-on electrochemiluminescence (ECL) biosensor for detecting concanavalin A (Con A) was fabricated with phenoxy dextran-graphite-like carbon nitride (DexP-g-C3N4) as signal probe. In this construction strategy, the nanocomposites of three-dimensional graphene and gold nanoparticles (3D-GR-AuNPs) were used as matrix for high loading of glucose oxidase (GOx), which served as recognition element for bounding Con A. Con A further interacted with DexP-g-C3N4 through a specific carbohydrate-Con A interaction to achieve a sandwiched scheme. With the increase of Con A incubated onto the electrode, the ECL signal resulted from DexP-g-C3N4 would enhance, thus achieving a signal-on ECL biosensor for Con A detection. Due to the integration of the virtues of 3D-GR-AuNPs and the excellent ECL performance of DexP-g-C3N4, the prepared biosensor exhibits a wide linear response range from 0.05 ng/mL to 100 ng/mL and a low detection limit of 17 pg/mL (S/N=3).

A novel ultrasensitive ECL sensor for DNA detection based on nicking endonuclease-assisted target recycling amplification, rolling circle amplification and hemin/G-quadruplex

In this study, we describe a novel universal and highly sensitive strategy for the electrochemiluminescent (ECL) detection of sequence specific DNA at the aM level based on Nt.BbvCI (a nicking endonuclease)-assisted target recycling amplification (TRA), rolling circle amplification (RCA) and hemin/G-quadruplex. The target DNAs can hybridize with self-assembled capture probes and assistant probes to form “Y” junction structures on the electrode surface, thus triggering the execution of a TRA reaction with the aid of Nt.BbvCI. Then, the RCA reaction and the addition of hemin result in the production of numerous hemin/G-quadruplex, which consume the dissolved oxygen in the detection buffer and result in a significant ECL quenching effect toward the O₂/S₂O₈²⁻ system. The proposed strategy combines the amplification ability of TRA, RCA and the inherent high sensitivity of the ECL technique, thus enabling low aM (3.8 aM) detection for sequence-specific DNA and a wide linear range from 10.0 aM to 1.0 pM. At the same time, this novel strategy shows high selectivity against single-base mismatch sequences, which makes our novel universal and highly sensitive method a powerful addition to specific DNA sequence detection.

Electrochemiluminescent immune-modified electrodes based on Ag2Se@CdSe nanoneedles loaded with polypyrrole intercalated graphene for detection of CA72-4

This work described a new electrochemiluminescence (ECL) immunosensor based on polypyrrole intercalated graphene and Ag2Se@CdSe nanoneedles. The novel nanomaterial Ag2Se@CdSe, with needle-like morphology, was synthesized for the first time. The prepared Ag2Se@CdSe nanoneedles exhibited good luminous performance in the presence of K2S2O8. Polypyrrole intercalated amination graphene with high specific binding sites and excellent electrochemical performance was used as the platform for the sensor. The developed ECL immunosensor was used for the detection of CA72-4 with good linear relation in the range from 10(-4) to 20 U/mL and low detection limit of 2.1 × 10(-5) U/mL (S/N = 3). The developed ECL immunosensor with high sensitivity and spectral selectivity can be used for detection of real samples. Ag2Se@CdSe nanoneedles could be promising candidate emitter for ECL biosensors in the future.

Electrochemiluminescence sensor for dopamine with a dual molecular recognition strategy based on graphite-like carbon nitride nanosheets/3,4,9,10-perylenetetracarboxylic acid hybrids

Preparation of an ECL sensor and graphite-like carbon nitride nanosheets/3,4,9,10-perylenetetracarboxylic acid hybrids.

An electrochemiluminescence biosensor for dopamine based on the recognition of fullerene-derivative and the quenching of cuprous oxide nanocrystals

Based on the multifunctional fullerene-derivative (l-Cys–C₆₀–APBA) and the cuprous oxide (Cu₂O) nanocrystals, an electrochemiluminescence biosensor for dopamine was constructed.

Paper-based electrochemiluminescence origami cyto-device for multiple cancer cells detection using porous AuPd alloy as catalytically promoted nanolabels

The detection of cancer cells is important and fundamental for cancer diagnosis and therapy, which has attracted considerable interest recently. Although traditional cyto-sensors have been widely explored due to their high sensitivity and selectivity, it is still a challenge to develop a low-cost, portable, disposable, fast, and easy-to-use cancer cell detection method for applying in the field of cancer diagnosis and therapy. Herein, to address these challenges, we developed a microfluidic paper-based electrochemiluminescence origami cyto-device (μ-PECLOC), in which aptamers modified 3D macroporous Au-paper electrodes were employed as the working electrodes and efficient platforms for the specific cancer cells capture. Owing to the effective disproportionation of hydrogen peroxide and specific recognition of mannose on cell surface, concanavalin-A conjugated porous AuPd alloy nanoparticles were introduced into this μ-PECLOC as the catalytically promoted nanolabels for peroxydisulfate ECL system. Under the optimal conditions, the proposed μ-PECLOC exhibited excellent analytical performance with good stability, reproducibility, and accuracy, towards the cyto-sensing of four types of cancer cells indicating the potential applications to facilitate effective and multiple early cancer diagnosis and clinical treatment.

Synthesis of multi-fullerenes encapsulated palladium nanocage, and its application in electrochemiluminescence immunosensors for the detection of Streptococcus suis Serotype 2

A novel functionalized material is synthesized using surface-decorated fullerene (C60) to encapsulate hollow and porous palladium nanocages (PdNCs), and is applied to fabricate an electrochemiluminescence (ECL) immunosensor for the detection of Streptococcus suis Serotype 2 (SS2). PdNCs with hollow interiors and porous walls are prepared using a galvanic replacement reaction between silver nanocubes and metal precursor salts. Then, C60 reacts with L-cysteine (L-Cys) to form L-Cys functionalized C60 (C60-L-Cys), which has a better biocompatibility, conductivity, and hydrophilicity compared to C60 and possesses abundant -SH groups on the surface. Because of the special interaction between -SH and PdNCs, the obtained C60-L-Cys is adsorbed around the PdNCs to form an interesting structure with multiple spheres encapsulating the cage. The resultant functionalized material (C60 -L-Cys-PdNCs) has a high specific surface area, good electrocatalytic ability, and efficient photocatalytic activity, and is used to construct an ECL immunosensor for the detection of SS2. The ECL signal amplified strategy is performed by using the novel coreactant (C60-L-Cys) and in situ generation of O2 thus creating the S2O8(2-)-O2 ECL system. As a result, a wide linear detection range of 0.1 pg mL(-1) to 100 ng mL(-1) is acquired with a relatively low detection limit of 33.3 fg mL(-1).

Binding-induced autonomous disassembly of aptamer-DNAzyme supersandwich nanostructures for sensitive electrochemiluminescence turn-on detection of ochratoxin A

The self-assembled DNA nanostructure has been one of the most interesting research areas in the field of nanoscience, and the application of the DNA self-assembled nanostructures in biosensing is still in the early stage. In this work, based on the target-induced autonomous disassembly of the aptamer-DNAzyme supersandwich nanostructures, we demonstrated a highly sensitive strategy for electrochemiluminescent (ECL) detection of ochratoxin A (OTA). The aptamer-DNAzyme supersandwich nanostructures, which exhibited significant ECL quenching effect toward the oxygen/persulfate (O2/S2O8(2-)) system, were self-assembled on the gold electrode surface. The presence of the target OTA and the exonuclease (RecJf) resulted in autonomous disassembly of the nanostructures and cyclic reuse of OTA, leading to efficient recovery of the ECL emission and highly sensitive detection of OTA. Our developed method also showed high selectivity against other interference molecules and can be applied for the detection of OTA in real red wine samples, which offers the proposed method opportunities for designing new DNA-based nanostructures for biosensing applications.

Highly enhanced electrochemiluminescence based on pseudo triple-enzyme cascade catalysis and in situ generation of co-reactant for thrombin detection

In this work, a novel pseudo triple-enzyme cascade catalysis amplification strategy was employed to fabricate a highly sensitive electrochemiluminescence (ECL) aptasensor for thrombin (TB) detection.

3,4,9,10-Perylenetetracarboxylic dianhydride functionalized graphene sheet as labels for ultrasensitive electrochemiluminescent detection of thrombin

A novel tracer, 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) functionalized graphene sheet (GS) composite (GS-TCDA), is employed to label the secondary anti-thrombin aptamer (TBA) to construct an ultrasensitive electrochemiluminescent sandwich-type aptasensor. The GS provided large surface area for loading abundant PTCDA and TBA with good stability and biocompatibility. Because of the excellent electroconductivity of GS and the desirable optical properties of PTCDA, the as-formed Apt II bioconjugate considerably amplified the electrochmiluminescence (ECL) signal of peroxydisulfate (S(2)O(8)(2-)) and worked as the desirable label for Apt II. On the basis of the considerably amplified ECL signal and sandwich format, an extremely wide range from 1 fM to 1 nM with an ultralow detection limit of 0.33 fM for thrombin was obtained. Additionally, the selectivity and stability of the proposed aptasensor were also excellent. Thus, this procedure has great promise for detection of thrombin present at ultra-trace levels during early stage of diseases.

A novel chemiluminescence reaction system for the determination of norfloxacin with Ag(III) complex

A novel chemiluminescence (CL) system for the determination of norfloxacin (NFLX) is developed based on the direct CL reaction of [Ag(HIO(6))(2)](5-)-H(2)SO(4)-NFLX system. The possible mechanism of CL emission and enhancing effect was discussed by comparing UV, fluorescence and CL spectra. [Ag(HIO(6))(2)](5-) in the presence of H(2)SO(4) could produce CL emission at 490 nm, this might be caused by the excited state (O(2))(2)*. The enhancing effect of NFLX may be produced through an intermolecular energy transfer from part of (O(2))(2)* to NFLX molecule and complex of Ag(3+) and NFLX. The CL intensity emission intensity was linear in the range 1.34 x 10(-8) to 5.44 x 10(-6) gmL(-1) with correlation coefficient of 0.9982. The detection limit (s/n=3) was 3.10 x 10(-9) gmL(-1). The recovery was in the range of 90.0-104% with the RSD of 1.1-2.8%. The proposed flow injection CL method was applied satisfactorily for the determination of NFLX in capsule, human serum and urine.