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Zhang Y.,University of Jinan | Li L.,University of Jinan | Lu J.,University of Jinan | Ge L.,University of Jinan | And 4 more authors.
Sensors and Actuators, B: Chemical | Year: 2013

A novel triple catalysis amplification strategy for simultaneous multiplexed electrochemical immunoassays based on cactus-like MnO2 functionalized nanoporous gold (NPG-MnO2) was designed. The NPG-MnO2 with enhanced catalytic activity, electrical conductivity and solubility was synthesized by an efficient, green and controllable approach. The obtained material was further characterized and used as matrices to immobilize the redox probes to produce a multiplexed electrochemical immunoassay. With the employment of the as prepared bioconjugates, triple catalysis amplification strategy was described duo to the enhanced catalytic effects of horseradish peroxidase (HRP) and two bio-mimetic enzymes (NPG and MnO2) through sandwich-type immunoassay protocol. © 2013 Elsevier B.V. Source

Zhang Y.,University of Jinan | Ge L.,University of Jinan | Ge S.,University of Jinan | Yan M.,University of Jinan | And 5 more authors.
Electrochimica Acta | Year: 2013

A novel strategy was reported for the preparation of TiO2 nanobelts by the acid-assisted hydrothermal method. Complex nanopaper based on the TiO2 nanobelts and graphene was fabricated via a modified paper-making process. The as-prepared TiO2-graphene structure inherited the excellent electron transport of graphene and facilitated the spatial separation of photo-generated charge carrier, therefore resulting in the enhanced photocurrent, and making it a promising candidate for developing photoelectrochemical (PEC) biosensors. Thus, an advanced PEC biosensing platform for the detection of carcinoembryonic antigen was proposed at relatively low applied potential on screen-printed working paper-electrode using the as-prepared TiO2-graphene complex nanopaper. The complex nanopaper with good biocompatibility showed high PEC intensity and satisfactory stability, all of which held great promise for the fabrication of PEC biosensors with improved sensitivity. Furthermore, the TiO2-graphene complex nanopaper based PEC biosensor in this study was anticipated to provide the chance for the design of high-performance PEC biosensors for the detection of other enzymes and biomolecules. © 2013 Elsevier Ltd. All rights reserved. Source

Sun G.,University of Jinan | Zhang L.,University of Jinan | Zhang Y.,University of Jinan | Yang H.,University of Jinan | And 5 more authors.
Biosensors and Bioelectronics | Year: 2015

Herein, an origami multiplexed enzyme-free electrochemical (EC) immunodevice is developed for the first time. Typically, ZnO nanorods (ZNRs) modified reduced graphene oxide (rGO)-paper electrode is used as a sensor platform, in which rGO improves the electronic transmission rate and ZNRs provide abundant sites for capture probes binding. Furthermore, by combining the large surface area of rGO and high catalytic activity of bovine serum protein (BSA)-stabilized silver nanoparticles (Ag@BSA) toward H2O2 reduction, rGO/Ag@BSA composites can be used as an excellent signal labels. The current signal is generated from the reduction of H2O2 and further amplified by a subsequent signal labels-promoted deposition of silver. Under optimal conditions, the proposed immunoassays exhibit excellent precision, high sensitivity and a wide linear range of 0.002-120mIUmL-1 for human chorionic gonadotropin, 0.001-110ngmL-1 for prostate-specific antigen, and 0.001-100ngmL-1 for carcinoembryonic antigen. The results for real sample analysis demonstrate that the newly constructed immunosensor arrays provide a simple and cost-effective method for clinical applications. © 2015 Elsevier B.V. Source

Li L.,University of Jinan | Zhang L.,University of Jinan | Yu J.,University of Jinan | Ge S.,University of Jinan | Song X.,Cancer Research Center Shandong Tumor Hospital
Biosensors and Bioelectronics | Year: 2015

Graphene has shown great potential for use in biosensors because of its versatile surface modification, good water dispersibility, and extraordinary electrical conductivity. Here, a novel enzyme-free and all-graphene electrochemical immunosensor, based on two novel graphene nanocomposites, for the ultrasensitive immunosensing of α-fetoprotein (AFP) was reported. Noncovalent ultrathin gold nanowire functionalized graphene sheets (GNWs/GO) with the extraordinary biological and electrical properties, which exhibited high water solubility and further biological molecule functionalization, was prepared in situ solution phase to be used as an enhanced electrochemical sensing platform. In addition, a new electrocatalyst, CuS nanoparticle-decorated graphene (CuS/GO) composites was successfully prepared by a simple method for in situ growth of CuS on the surface of graphene sheets. Covalent binding of the detection antibody of AFP on the CuS/GO composites produced a sensitive electrochemical bioprobe for detection of AFP by sandwich immunosensing. The corresponding immunosensor, employing an inexpensive and portable 3D paper-based analytical device, possessed a wide calibration range of 0.001-10 ng mL-1 and a low detection limit of 0.5 pg mL-1 (S/N=3), which was successfully applied to the detection of AFP in serum samples from both healthy people and cancer patients. The present work thus demonstrated the promising application of graphene-based nanocomposites in developing highly sensitive, environmentally friendly, and cost-effective electrochemical biosensors. © 2015 Elsevier B.V. Source

Zhang Y.,University of Jinan | Liu W.,University of Jinan | Ge S.,University of Jinan | Yan M.,University of Jinan | And 4 more authors.
Biosensors and Bioelectronics | Year: 2013

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 (SiO2@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. © 2012 . Source

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