Hong Ke

Electrochemiluminescence resonance energy transfer system between GNRs and Ru(bpy)32+: Application in magnetic aptasensor for β-amyloid

Electrochemiluminescent (ECL) assay has gradually drawn increasing interest in the biomedical analysis. This paper proposed a new methodology for ultrasensitive and facile detection of Alzheimers disease marker β-amyloid (Aβ) by fabricating a sandwich-type ECL sensing platform. Herein, electrochemiluminescence resonance energy transfer (ECL-RET) was employed to determine Aβ concentration, which can be attributed to the quenching effect from RET between Ru(bpy)32+ and gold nanorods (GNRs) acting as ECL-RET electron donor and acceptor, respectively. In this protocol, mesoporous carbon nanospheres were adopted to immobilize ECL reactant Ru(bpy)32+ and antibody via nafion to acquire the RET donor nanocomposites (MOCs/nafion/Ru(bpy)32+/antibody), which were tightly interconnected with epoxy group functionalized Fe3O4 nanoparticles. It is of vital importance that GNRs with exquisite rod shape were synthesized and exhibited a typical absorption peak at 650nm to quench ECL signal of Ru(bpy)32+ effectively. In addition, the ECL emission decreased linearly with the logarithm of Aβ concentration in a wide linear range from 1.0 × 10-5 to 100ng/mL with a detection limit of 4.2 × 10-6ng/mL. Furthermore, distinctive and desirable properties were verified to declare the promise for being applicable to analyze the Aβ content in real Alzheimers cerebrospinal fluid samples with satisfactory results.

Electrochemiluminescence evaluation for carbohydrate antigen 15-3 based on the dual-amplification of ferrocene derivative and Pt/BSA core/shell nanospheres

Herein, a novel methodology for ultrasensitive and facile breast cancer biomarker carbohydrate antigen 15-3 (CA15-3) evaluation was proposed by fabricating a sandwiched ECL immunosensor. In the protocol, MOCs-Fc and Pt@BSA-luminol nanohybrids were successfully synthesized and further employed to achieve dual-amplification strategy for luminol-H2O2 system. Notably, inherent porous microstructure and large specific surface area from MOCs enabled a high loading of Fc, which succeeded in catalyzing luminol-H2O2 ECL emission and therefore enhancing ECL response. In addition, higher sensitivity could be realized due to the excellent electronic conductivity of MOCs. Furthermore, the as-obtained Pt@BSA- luminol was not only employed as capture probe to recognize CA15-3 after hybridization with Ab2, but also played a crucial role in acting as ECL signal probe due to the presence of massive luminol. It is of vital importance that Pt@BSA core/shell nanospheres showed admirable catalytic effect towards H2O2, which resulted in more excited state luminol and stronger ECL intensity. Therefore, the synergistic amplification strategy of MOCs-Fc and Pt@BSA nanohybrids offered an extremely enhanced ECL signal. The well-established applicable ECL immune- sensing platform displayed favorable analytical performance for CA15-3. In summary, the proposed ECL immunosensor opened a new era for sensitive CA15-3 evaluation and offered a promising platform for clinical breast cancer diagnostics.

Sandwich-format ECL immunosensor based on Au star@BSA-Luminol nanocomposites for determination of human chorionic gonadotropin

A sandwich-configuration electrochemiluminescence (ECL) immunosensor based on Au star@BSA-Luminol nanocomposites for ultrasensitive determination of human chorionic gonadotropin (HCG) has been developed. In this work, nanostructured Polyaniline hydrogels (Pani) decorated with Pt nanoparticles (Pani/Pt) were utilized to construct the base of this immunosensor, greatly increasing the amount of loaded capture antibodies (Ab1) via linkage reagent glutaraldehyde (GA). The used conducting Pani/Pt nanocomposites possessed the unique features, such as large surface area, high electron transfer speed and favorable electrocatalytic activities of hydrogen peroxide, which offered a prominent platform for this sandwich-sensor and acted as efficient ECL signal amplifier also. Furthermore, we employed horseradish peroxidase (HRP) to block the nonspecific binding sites instead of commonly used bovine serum albumin (BSA), which further amplified the signal of luminol in the present of hydrogen peroxide (H2O2). In addition, Au star@BSA nanocomposites with excellent water solubility, low-toxicity and great biocompatibility were prepared and used to immobilize HCG detection antibodies (Ab2) and luminescent material luminol. Then, the above-synthetized Luminol-Au star@BSA-Ab2 complex was attached to the modified sensor by sandwiched immunoreactions. Under the optimized conditions, the proposed immunosensor exhibited a sensitive detection of HCG in a wide linear range from 0.001 to 500mIUmL-1 with a detection limit of 0.0003mIU/mL (S/N = 3). All the results indicated that such a sandwiched HCG immunosensor exhibited favorable ECL analytical performance. This developed method may be potentially used to recognize other clinical protein and display a novel ideal to construct an immunosensor.

A MWCNTs-Pt nanohybrids-based highly sensitive electrochemiluminescence sensor for flavonoids assay

Electrochemiluminescent (ECL) assay has gradually drawn increasing interest to be considered as one of the potential strategies to be applicable in a wide range of medicine target determination. In this protocol, a facile and ultrasensitive ECL sensor platform was developed aiming at rapidly quantitative detection of polyphenolic flavonoids based on multiwall carbon nanotubes (MWCNTs)/platinum nanoparticles (PtNPs) nanohybrids/nafion/Ru(bpy)32+ modified glassy carbon electrode (GCE) in Ru(bpy)32+/tri-n-propylamine (TPA) co-reaction system. Attributed to the synergistic ECL signal amplification of both PtNPs and MWCNTs facilitating the electron transfer, this proposed sensor could sensitively analyze the flavonoids through an annihilation ECL emission mechanism since the less generated amount of excitation state Ru(Ⅱ)* on account of the principle that flavones are prone to donate electrons and scavenge free radicals to further show a competitive relationship with Ru(Ⅲ) on the reaction with TPA*. The influences of pH, Ru(bpy)32+ absorption time and TPA co-reactant concentration were investigated and the sensor exhibited a linear response to flavonoids when the concentration ranges from 6.50×10-11 to 1.00×10-7M with a detection limit (LOD) of 2.17×10-11M (S/N=3) upon the optimized conditions. Furthermore, high sensitivity, excellent stability and reproducibility were verified to declare the promise for being applicable to analyze the flavones content in real flavones medicine samples and ginkgo leaves extracts with satisfactory results.

Electrochemiluminescence resonance energy transfer biosensor between the glucose functionalized MnO2 and g-C3N4 nanocomposites for ultrasensitive detection of concanavalin A

An electrochemiluminescence (ECL) analytical platform was initially proposed based on the electrochemiluminescence resonance energy transfer (ECL-RET) mechanism for ultrasensitive detection of Concanavalin A (Con A). In this protocol, the glucose functionalized carboxylic g-C3N4 nanosheets (g-C3N4-COOH@Glu) and MnO2 nanoparticles covered carboxylic multi-wall carbon nanotubes (BSA@MnO2-MWCNTs-COOH@Glu) were synthesized and acted as ECL-RET electron donor and acceptor, respectively. Herein, glucose was served as the recognition element for binding Con A and MWCNTs was utilized as the carrier materials for loading MnO2. When the quenching probe BSA@MnO2-MWCNTs-COOH@Glu was incubated onto the modified electrodes via the specific carbohydrate-Con A interaction, the ECL signals of g-C3N4-COOH@Glu which used S2O82- as its coreactant have drastically declined. Under optimum conditions, this biosensor performed a sensitive detection of the Con A ranging from 1 × 10-5 to 1 × 104 ng/mL with a detection limit of 2.2 fg/mL (S/N = 3). Moreover, favorable analytical outcomes for detecion Con A in actual serum samples were obtained, exhibiting huge applications in clinical diagnosis of this assay.

An ultrasensitive electrochemiluminescence immunosensor based on platinum nickel nanocubes-L-cysteine-luminol nanocomposite

An ultrasensitive electrochemiluminescence (ECL) immunosensor was initially developed for quantitative detection of carbohydrate antigen 15-3 (CA15-3) using platinum nickel nanocubes-L-cysteine-luminol nanocomposite (PtNi NCs-L-Cys-luminol) as signal probe. Herein, the PtNi NCs-L-Cys-luminol nanocomposite was modified on the glassy carbon electrode (GCE) surface via the film-forming properties of chitosan. Then, the CA15-3 antibody was attached to the modified electrode surface by amidating reaction to construct the ECL immunosensor. Experimental results showed that with the capturing of CA15-3 antigen molecules on the immunosensor, the ECL signal intensity observably decreased, indicating the quenching detection principle of electrochemiluminescence. Under optimal experimental conditions, the constructed ECL immunosensor displayed remarkable performance for CA15-3 detection ranging from 0.0005 U/mL to 500 U/mL, with a relatively low detection limit of 0.000167 U/mL (S/N = 3). It might be ascribed to the fact that the PtNi NCs could dramatically promote the decomposition of H2O2 to produce various active free radical, thereby the ECL responses of luminol were prominently magnified and its sensitivity was effectively increased. The immunosensor exemplified its advantages of easy fabrication, fast analysis, high sensitivity, good reproducibility and selectivity. Moreover, the recovery tests exhibited that the sensor can be used to sensitively detect CA15-3 in serum samples, suggesting potential application prospect in bioanalysis.