scholarly journals Label-Free Electrochemical Aptasensor for Sensitive Detection of Malachite Green Based on Au Nanoparticle/Graphene Quantum Dots/Tungsten Disulfide Nanocomposites

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 229 ◽  
Author(s):  
Qianqian Wang ◽  
Xiaofei Qin ◽  
Liping Geng ◽  
Yan Wang
Keyword(s):  
Quantum Dots ◽  
Malachite Green ◽  
Au Nanoparticles ◽  
Graphene Quantum Dots ◽  
Tungsten Disulfide ◽  
Electrochemical Sensing ◽  
Au Nanoparticle ◽  
Label Free ◽  
Electrochemical Aptasensor ◽  
Fish Samples

A label-free electrochemical aptasensor was fabricated to sensitively determine malachite green (MG) based on Au nanoparticles/graphene quantum dots-tungsten disulfide nanosheet composite film modified glassy carbon electrode (AuNPs/GQDs-WS2/GCE). A facial strategy for the self-assembly of graphene quantum dots (GQDs) on tungsten disulfide nanosheets (WS2) was developed to fabricate 0D/2D nanocomposites. As-prepared GQDs-WS2 hybrids exhibited significantly enhanced electrocatalytic properties, and were first used as electroactive materials to construct electrochemical aptasensor. The AuNPs/GQDs-WS2/GCE was prepared through depositing Au nanoparticles on the surface of the GQDs-WS2 film, which acted as the electrochemical sensing matrix to covalently immobilize the aptamers of MG via the Au–S bond. In this label-free proposal, the aptasensor was applied to detect MG by monitoring voltammetric signal resulted from electrochemical oxidation of the MG captured by the aptamer. Under the optimized conditions, the aptasensor showed a wide linear range from 0.01 to 10 μM for MG detection with a low detection limit of 3.38 nM (S/N = 3). The method was applied to determination of MG in spiked fish samples and gave satisfactory results.

scholarly journals Graphene Quantum Dots as Nanozymes for Electrochemical Sensing of Yersinia enterocolitica in Milk and Human Serum

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2189 ◽  
Author(s):  
Sumeyra Savas ◽  
Zeynep Altintas
Keyword(s):  
Quantum Dots ◽  
Human Serum ◽  
Pathogenic Bacteria ◽  
Graphene Quantum Dots ◽  
High Sensitivity ◽  
Electrochemical Sensing ◽  
Sample Treatment ◽  
Label Free ◽  
Human Pathogens ◽  
Free System

The genus Yersinia contains three well-recognized human pathogens, including Y. enterocolitica, Y. pestis, and Y. pseudotuberculosis. Various domesticated and wild animals carry Yersinia in their intestines. Spread to individuals arises from eating food or water contaminated by infected human or animal faeces. Interaction with infected pets and domestic stock may also lead to infection. Yersinia is able to multiply at temperatures found in normal refrigerators; hence, a large number of the bacteria may be present if meat is kept without freezing. Yersinia is also rarely transmitted by blood transfusion, because it is able to multiply in stored blood products. Infection with Yersinia can cause yersiniosis, a serious bacterial infection associated with fever, abdominal pain and cramps, diarrhea, joint pain, and symptoms similar to appendicitis in older children and adults. This paper describes a novel immunosensor approach using graphene quantum dots (GQDs) as enzyme mimics in an electrochemical sensor set up to provide an efficient diagnostic method for Y. enterecolitica. The optimum assay conditions were initially determined and the developed immunosensor was subsequently used for the detection of the bacterium in milk and human serum. The GQD-immunosensor enabled the quantification of Y. enterocolitica in a wide concentration range with a high sensitivity (LODmilk = 5 cfu mL−1 and LODserum = 30 cfu mL−1) and specificity. The developed method can be used for any pathogenic bacteria detection for clinical and food samples without pre-sample treatment. Offering a very rapid, specific and sensitive detection with a label-free system, the GQD-based immunosensor can be coupled with many electrochemical biosensors.

N-doped graphene quantum dots as an effective photocatalyst for the photochemical synthesis of silver deposited porous graphitic C3N4 nanocomposites for nonenzymatic electrochemical H2O2 sensing

RSC Advances ◽  
2014 ◽  
Vol 4 (31) ◽  
pp. 16163-16171 ◽  
Author(s):  
Deli Jiang ◽  
Yuan Zhang ◽  
Haoyu Chu ◽  
Jie Liu ◽  
Jin Wan ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Electrochemical Sensing ◽  
Photochemical Synthesis ◽  
Doped Graphene ◽  
H2o2 Sensing

N-doped GQDs served as an effective photocatalyst for the photochemical synthesis of silver deposited porous g-C3N4 nanocomposites for electrochemical sensing.

Label-free approach for electrochemical ferritin sensing using biosurfactant stabilized tungsten disulfide quantum dots

2020 ◽  
Vol 151 ◽  
pp. 111979 ◽  
Author(s):  
Mayank Garg ◽  
Mary Chatterjee ◽  
Amit L. Sharma ◽  
Suman Singh
Keyword(s):  
Quantum Dots ◽  
Tungsten Disulfide ◽  
Label Free

Novel oxidative cutting graphene oxide to graphene quantum dots for electrochemical sensing application

2016 ◽  
Vol 8 ◽  
pp. 127-133 ◽  
Author(s):  
Jiawei Wen ◽  
Mingjie Li ◽  
Jiadong Xiao ◽  
Chenming Liu ◽  
Zehui Li ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Oxide ◽  
Graphene Quantum Dots ◽  
Electrochemical Sensing ◽  
Sensing Application
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