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ABSTRACT: Aimed at the facile detection of lengthy DNA molecules, an easily operated sandwich-type electrochemiluminescence (ECL) DNA biosensor was constructed on a glassy carbon electrode (GCE) based on CdTe quantum dots coated hollow ZnO nanoparticles (CdTe-ZnO NPs)-S2O8(2-) ECL system in this work. To fabricate a high-performance protocol, the GCE surface was successively modified by graphene nanosheet (GS), carbon nanotube (CNT) and gold nanoparticles (AuNPs) to form AuNPs dotted CNT-GS composites (Au@CNT-GS) platform, which improved the electronic transmission rate as well as increased the amount of immobilized capture probe CMV-F (S1). For further ultrasensitive, stable and low-potential ECL detection, CdTe-ZnO NPs were synthesized, and employed to label signal probe T7 promoter (S3). Based on the hybridization effect, the immobilized capture probe S1, target DNA and labeled signal probe S3 formed a sandwich-type DNA complex, which produced the ECL emission in the presence with S2O8(2-) coreactant. Under optimal conditions, the DNA ECL biosensor showed a good linear range over 10(-14) M to 10(-19) M with a low detection limit of 0.61 × 10(-19) M. The proposed strategy demonstrates a reproducible, stable, and potent method that can be expanded to detect the genome which exists in living cells.
The Analyst 05/2013; · 4.23 Impact Factor
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ABSTRACT: A simple approach based on exfoliating and disintegrating treatments for graphite oxide, followed by hydrothermal synthesis, was developed to prepare water-soluble graphene quantum dots (GQDs). The as-prepared GQDs exhibited bright blue emission under ultraviolet irradiation (∼365nm), and showed an excitation-independent photoluminescence feature. More importantly, a newly anodic electrochemiluminescence (ECL) was observed from the water-soluble GQDs with H2O2 as coreactant for the first time, and the ECL induced a strong light emission at a low potential (ca. 0.4V vs. Ag/AgCl). The ECL mechanism is investigated in detail. Employing SiO2 nanospheres as signal carrier, a novel SiO2/GQDs ECL signal amplification labels were synthesized based on which a ultrasensitive ECL aptamer sensor was proposed. Under the optimized experimental conditions, the proposed ECL aptamer sensor exhibited excellent analytical performance for adenosine triphosphate (ATP) determination, ranging from 5.0×10(-12) to 5.0×10(-9)molL(-1) with the detection limit of 1.5×10(-12)molL(-1). Due to the low cytotoxicity and excellent biocompatibility, GQDs are demonstrated to be an eco-friendly material as well as excellent ECL labeling agents for biosensor.
Biosensors & bioelectronics 03/2013; 47C:271-277. · 5.43 Impact Factor
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ABSTRACT: Convenient sensor array for simultaneous multi-analyte testing was increasingly needed in clinical diagnosis. A novel electrochemiluminescence (ECL) immunosensor array for the sequential detection of multiple tumor markers was developed by site-selectively immobilizing multiple antigens on different electrodes. Disposable indium tin oxide (ITO) glass array was employed as detection platform. With a sandwich-type immunoassay format, the amount of carbon dots coated silica (SiO(2)@C-dots) labeled antibodies increased with the increment of antigens in the samples. The ECL signal from different immunosensors was collected in turn by a photomultiplier (PMT) with the aid of a home-made potential transformer equiped with a home-made multiplexed-switch. Using carcino embryonic antigen (CEA), prostate specific antigen (PSA) and α-fetoprotein (α-AFP) as model analytes, the proposed immunoassay exhibited excellent precision and sensitivity. For all three analytes, the relative standard deviations (RSDs) for six times detection were lower than 7.1% and the detection limits were in the range of 0.003-0.006ngmL(-1). The results for real sample analysis demonstrated that the newly constructed immunosensor array provided a rapid, simple, simultaneous multi-analyte immunoassay with high throughput, cost-effective and sufficiently low detection limits for clinical applications. Importantly, the novel individually addressable immunosensor array for multi-analyte immunoassay by introducing the ECL readout mechanism with the aid of the home-made potential transformer and multiplexed-switch could be a useful supplement to commercial assay methods in clinical chemistry.
Biosensors & bioelectronics 09/2012; · 5.43 Impact Factor
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ABSTRACT: A potential-resolution strategy for multiplex electrochemiluminescence (ECL) immunoassay on a microfluidic paper-based analytical device (μ-PAD) was demonstrated for the first time, using tris-(bipyridine)-ruthenium(ii) (Ru(bpy)(3)(2+)) and carbon nanodots (CNDs) as the ECL labels for high-throughput ECL immunoassay on μ-PAD. Based on this strategy, simultaneous detection of four tumor markers using only two screen-printed carbon working electrodes (one electrode for two analytes) on an immunodevice consisting of a piece of patterned paper (denoted as μ-PECLI in this work) was realized, which is a simplification of the configuration of traditional μ-PADs. As a further development of μ-PECLI in low-cost and disposable applications, battery-triggered (constant-potential) ECL detection on μ-PECLI was developed, allowing the traditional electrochemical workstation to be abandoned. In addition, to exactly control the output voltage of the battery, a low-cost and simple voltage-controller was designed and fabricated for the first time. The battery-triggered ECL immunoassay principle on μ-PECLI is explained. We found that the simultaneous determination of two analytes in one paper working zone could be achieved by controlling the operational constant-potential (+1.2 V for Ru(bpy)(3)(2+) labels and -1.2 V for CNDs labels (vs. Ag/AgCl auxiliary electrode)) by simply reversing the connection mode. Finally, four tumor markers in human serum samples from the Tumor Hospital were assayed and the results obtained were in acceptable agreement with the reference values from parallel single-analyte test. This battery-triggered μ-PECLI provides a new strategy for high-throughput, low-cost, sensitive, automated and simultaneous multiplex immunoassay and point-of-care diagnosis.
Lab on a Chip 09/2012; 12(21):4489-98. · 5.67 Impact Factor
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ABSTRACT: A low-cost, portable rechargeable battery was firstly used to fabricate a battery-triggered, screen-printed two-electrode electrochemiluminescent immunoassay on a 3D microfluidic origami electronic device.
Chemical Communications 09/2012; 48(80):9971-3. · 6.17 Impact Factor
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ABSTRACT: A novel electrochemiluminescence (ECL) immunosensor for sensitive detection of human chorionic gonadotrophin antigen (HCG-Ag) was constructed using CdTe quantum dot functionalized nanoporous PtRu alloys (QDs@PtRu) as labels for signal amplification. In this paper, nanoporous PtRu alloy was employed as the carrier for immobilization of CdTe QDs and antibodies. Primary monoclonal antibody to alfa-HCG antigen (McAb(1)) was immobilized onto the surface of chitosan coated Fe(3)O(4) magnetic nanoparticles (Fe(3)O(4)/CS MNPs) by glutaraldehyde (GA) as coupling agent. Then McAb(1) could be easily separated and assembled on the surface of indium tin oxide glass (ITO) owing to their excellent magnetic properties with external magnetic forces holding the MNPs. Due to signal amplification from the high loading of CdTe QDs, 4.67-fold enhancements in ECL signal for HCG-Ag detection was achieved compared to the unamplified method (single QDs as labels). Under optimal conditions, a wide detection range (0.005~50 ng mL(-1)) and low detection limit (0.8 pg mL(-1)) were achieved through the sandwich-type immunosensor. The novel immunosensor showed high sensitivity and selectivity, excellent stability, and good reproducibility, and thus has great potential for clinical detection of HCG-Ag. In particular, this approach presents a novel class of combining bifunctional nanomaterials with preferable ECL properties and excellent magnetism, which suggests considerable potential in a wide range of applications for bioassays.
The Analyst 03/2012; 137(9):2176-82. · 4.23 Impact Factor
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ABSTRACT: A novel flow injection chemiluminescence (FI-CL) sensor for the determination of bovine serum albumin (BSA) using molecularly imprinted polymeric microspheres (MIPMs) as recognition element is reported. The BSA-MIPM was synthesized by suspension polymerization in toluene, using methacrylic acid (MAA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker in the bovine serum albumin template molecule. Scanning electron microscope (SEM) was employed to characterize the surface morphology of the resultant imprinted microspheres. Molecular modeling was employed to simulate the possible recognition process of the MIPM. Then the synthesized BSA-MIPM was employed as recognition element by packing into flow cell to establish a novel FI-CL sensor. The chemiluminescence (CL) intensity was correlated linear with the concentration of BSA over the range of 1.0×10(-8) to 5.0×10(-6) g mL(-1) and the detection limit was 1.5×10(-9) g mL(-1). The relative standard deviation (RSD) for the determination of 1.0×10(-7) g mL(-1) BSA was 1.4% (n=11). The sensor is reusable and has a great improvement in sensitivity and selectivity for CL analysis. As a result, the new MIPM-CL sensor had been successfully applied to the determination of BSA in milk samples.
Biosensors & bioelectronics 10/2010; 26(2):632-7. · 5.43 Impact Factor
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ABSTRACT: A flow injection electrochemiluminescence (FI-ECL) analysis method for the determination of sibutramine in the presence of luminol was studied under conventional cyclic voltammetry in alkaline Na2CO3–NaHCO3 buffer solution (pH 8.0–12.0). This method is based on the enhanced ECL of luminol–sibutramine. Meanwhile, in order to overcome the drawbacks of conventional cells, a FI cell was designed, which is reusable and has a great improvement in sensitivity and selectivity for ECL analysis. Under the optimal experimental conditions, the enhanced ECL intensity was linearly related to the concentration of sibutramine in the range 1.0×10−8–1.0×10−6 g mL−1 with a detection limit of 2.48×10−9 g mL−1 and a correlation coefficient (R) of 0.9995. The relative standard deviation (RSD) for 1.0×10−7 g mL−1 samples was 2.1% (n=11). The possible mechanism discussed. The proposed FI-ECL method has been successfully applied to the determination of sibutramine in diet pill samples.Highlights► An electrochemiluminescence (ECL) system was studied to determine sibutramine. ► A flow injection cell was made to overcome the drawbacks of the conventional ones. ► The system was based on the enhanced ECL of luminol–sibutramine. ► The system can be satisfactorily applied to determine sibutramine in diet pills.
Journal of Luminescence. 131(7):1515-1519.
