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Gulou, China

Weng S.,Fujian Medical University | Liang D.,Fujian Medical University | Qiu H.,Fujian Medical University | Liu Z.,Fujian Medical University | And 6 more authors.
Sensors and Actuators, B: Chemical | Year: 2015

Abstract A rapid, facile fluorescence sensing strategy was developed for dopamine (DA) detection based on polydopamine (pDA) formed on the surface of graphene quantum dots (GQDs). The prepared GQDs were strongly luminescent because of the aromatic planar structure. DA could self-polymerize to pDA and snap to the surface of GQDs to form a thin film in alkaline environment, leading to quenching of fluorescence due to fluorescence resonance energy transfer (FRET). With the optimized conditions, the analytical performance illustrated high sensitivity, selectivity in a wide linear range with a detection limit of 8 nM. In addition, the unique method was successfully applied for DA injection test with satisfactory labeled amount. Finally, the proposed strategy was applied for DA detection in serum, wherein accurate results were obtained. © 2015 Elsevier B.V. Source

Cai X.,Fujian Medical University | Weng S.,Fujian Medical University | Guo R.,Fujian Medical University | Lin L.,Fujian Medical University | And 4 more authors.
Biosensors and Bioelectronics | Year: 2016

A ratiometric assay in an electrochemical immunosensor for tumor marker, herein carcinoembryonic antigen (CEA) was chosen as a model analyte, was developed to improve simplicity and accuracy. The immunosensor was fabricated via the simple expedient way of using Polythionine-gold (PTh-Au) as electrode modified material to be an internal reference signal and K3[Fe(CN)6] in electrolyte as an indicator signal. When the CEA was fixed on the modified electrode via immunoreaction, only the indicator signal sensitively altered; by contrast, the internal reference signal of PTh-Au remained constant at a suitable pH of the electrolyte. The ratio between the alterations of the indicator signal of K3[Fe(CN)6] and the constant internal reference signal can be used to monitor the concentration of CEA reliably, reproducibly, and sensitively. The prepared ratiometric electrochemical immunosensor could detect CEA with good specificity within a wide linear range from 0.005 ng/ml to 40 ng/ml with a detection limit of 2.2 pg/ml. Additionally, experimental results confirm that our proposed method is practical. Thus, this method can expand to recognize and test other protein markers. © 2016 Elsevier B.V. Source

Chen M.,Fujian Medical University | Zhao C.,Fujian Medical University | Chen W.,Fujian Medical University | Weng S.,Fujian Medical University | And 5 more authors.
Analyst | Year: 2013

The fabrication of a facile, sensitive, and versatile immunosensor for the quantification of metallothionein-3 (MT-3) is proposed in this work. The K 3[Fe(CN)6]-chitosan-glutaraldehyde (K-CS-GA) conjugate prepared from K3[Fe(CN)6], chitosan and glutaraldehyde was employed as the redox-active signal source. Carbon nanodots (C-dots) were coupled with Nafion to form the nanocomposite architecture layer to carry antibodies (Abs). C-dots enhanced the electrochemical response of the proposed immunosensor to improve the detection sensitivity. The fabrication steps of the immunosensor were characterized using differential pulse voltammetry (DPV) and cyclic voltammetry (CV). Antigen determination was achieved via the decreased current response of the K3[Fe(CN)6] caused by the insulated coupled antigen. The detected signals were proportional to the logarithm of the concentrations of MT-3 ranging from 5 pg mL-1 to 20 ng mL-1 with a detection limit of 2.5 pg mL-1 in PBS. The proposed immunosensor showed high sensitivity, good selectivity and reproducibility. Furthermore, detection results using real serum samples showed the immunosensor's potential applications in clinical diagnostics. © 2013 The Royal Society of Chemistry. Source

Zheng Z.,476 Hospital of PLA | Zheng Z.,Xiamen University | Qiu H.,Fujian Medical University | Zheng M.,476 Hospital of PLA | And 6 more authors.
Analytical Methods | Year: 2014

A simple, selective, and sensitive electrochemical sensor for detecting dopamine (DA) using a copper oxide (CuO) nanoleaf electrode as an active platform was developed in this work. The CuO nanoleaf electrode was fabricated via one-step chemical oxidation of copper foil immersed in an alkaline solution with a strong oxidant. The electrode exhibits selective and sensitive DA detection in the presence of ascorbic acid and uric acid in phosphate buffered saline (pH 8.0). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were conducted to test the electrochemical behaviour of DA in the CuO nanoleaf electrode. DPV anodic peak currents at approximately 0.20 V were enhanced by increasing DA concentrations. The developed electrochemical sensor presents two linear ranges of 1 μM to 7.5 μM and 7.5 μM to 140 μM, respectively. And the detection limit of the proposed method is 0.5 μM for DA. Applying the CuO nanoleaf electrode in actual determination of DA injection yields accurate results. Furthermore, the analytical results of DA in serum show that the developed method is a promising alternative approach for complex systems. This journal is © the Partner Organisations 2014. Source

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