Detection of Escherichia coli O157:H7 with Antibody Conjugated Amino-Functionalized Graphene Quantum Dots as Immunofluorescence Probes

2019 ◽  
Vol 807 ◽  
pp. 151-158
Author(s):  
Xiao Zhan Yang ◽  
Wen Lin Feng ◽  
Gao Chen ◽  
Hong Feng Guo ◽  
Dao Yuan Wang
Keyword(s):  
Escherichia Coli ◽  
Quantum Dots ◽  
Pathogen Detection ◽  
Low Cost ◽  
Graphene Quantum Dots ◽  
Spectroscopic Properties ◽  
Spectroscopic Techniques ◽  
Functionalized Graphene ◽  
Raman Spectroscopic ◽  
E Coli

Escherichia coli O157: H7 (E. coli O157: H7) is a foodborne pathogenic bacterium which can cause fever, diarrhoea and vomiting in humans. Thus, a rapid, simple, and specific bioprobe for pathogen detection in contaminated foods has been attracted more and more attention. In this work, the strong fluorescent amino-functionalized graphene quantum dots (af-GQDs) were prepared by hydrothermal method. The microtopographic height, surface morphology and spectroscopic properties of af-GQDs are characterized by the high resolution transmission electron microscope (HRTEM), atomic force microscope (AFM), UV-vis, fluorescence, Raman spectroscopic techniques. All the results showed that the af-GQDs can be effectively applied in the preparation of biocompatible immunofluorescence probe and in the detection of E. coli O157: H7. The minimum detection limit is 100 cfu/mL. It is a simple, rapid, sensitive, low-cost and easy to be popularized method, which provides a feasible way to monitor E. coli O157: H7 in food safety.

scholarly journals Efficient Synthesis of α-Oximinoketones using Carboxyl and Nitrite Functionalized Graphene Quantum Dots: Dual role of Nanostructure as a Catalyst and Reagent

2017 ◽  
Vol 12 (6) ◽  
pp. 4089-4096
Author(s):  
Ashkan Shomali ◽  
Hassan Valizadeh
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Reaction Times ◽  
Mineral Acid ◽  
Homogeneous Catalyst ◽  
Spectroscopic Techniques ◽  
Functionalized Graphene ◽  
Efficient Synthesis ◽  
Ft Ir ◽  
High Yields

Carboxyl and nitrite functionalized graphene quantum dots (CNGQDs) was used for the efficient synthesis of α-oximinoketones under free mineral acid conditions at room temperature. CNGQDs was prepared via o-nitrozation of carboxyl and hydroxyl graphene quantum dots (CHGQDs) and used as a nitrosonium source and also as an efficient acidic catalyst for the synthesis of α-oximinoketones. The structure of the catalyst was characterized by FT-IR, XRD, TGA and photoluminescence techniques. The structures of the synthesized products were confirmed by FT-IR, 1H-NMR and 13C-NMR spectroscopic techniques. Stability and recyclability of the prepared homogeneous catalyst was studied in details. Reaction times and yields of the products were compared with previous reported methods resulting high yields and also shorter reaction times.

scholarly journals Antibacterial Activity of Borassus flabellifer Vinegar-Graphene Quantum Dots Against Gram-Positive and Gram-Negative Bacteria

2021 ◽  
Vol 33 (11) ◽  
pp. 2662-2666
Author(s):  
Amnuay Noypha ◽  
Paweena Porrawatkul ◽  
Nongyao Teppaya ◽  
Parintip Rattanaburi ◽  
Saksit Chanthai ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Quantum Dots ◽  
Antibacterial Activity ◽  
Graphene Quantum Dots ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli

Borassus flabellifer vinegar–graphene quantum dots (BFV-GQDs) were successfully synthesized using a pyrolysis method with Borassus flabellifer vinegar (BFV) as the precursor. All the samples were characterized using ultraviolet-visible spectrophotometry (UV-Vis), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The antibacterial activities of BFV-GQDs against strains of Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus) were determined using the agar well diffusion method for preliminary screening, while minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using the broth macro-dilution method. The zones of inhibition were compared with those of citric acid–graphene quantum dots (CA-GQDs). It was observed that the synthesized BFV-GQDs demonstrated excellent antibacterial activity against Staphylococcus aureus (82.3%) and good antibacterial activity against Escherichia coli (73.3%). The MIC of BFV-GQDs against E. coli was 6.25 mg/mL and S. aureus was 12.5 mg/mL, whereas the MBC of BFV-GQDs against E. coli was 12.5 mg/mL and S. aureus was 25.0 mg/mL.

Facile synthesis of cysteine–functionalized graphene quantum dots for a fluorescence probe for mercury ions

RSC Advances ◽  
2015 ◽  
Vol 5 (118) ◽  
pp. 97598-97603 ◽  
Author(s):  
Tran Van Tam ◽  
Soon Ho Hong ◽  
Won Mook Choi
Keyword(s):  
Quantum Dots ◽  
Fluorescence Probe ◽  
Low Cost ◽  
Graphene Quantum Dots ◽  
Fluorescence Probes ◽  
Functionalized Graphene ◽  
Mercury Ions ◽  
Facile Synthesis ◽  
Highly Sensitive ◽  
Environmentally Friendly Method

We synthesized cystenine–functionalized graphene quantum dots (cys–GQDs) by a simple, low cost and environmentally friendly method and demonstrated them as highly sensitive and selective fluorescence probes for Hg2+ detection.

NiAg-graphene quantum dot-graphene hybrid with high oxidase-like catalytic activity for sensitive colorimetric detection of malathion

2021 ◽  
Author(s):  
Xu Dan ◽  
Ruiyi Li ◽  
Qinsheng Wang ◽  
Yongqiang Yang ◽  
Haiyan Zhu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Oxide ◽  
Catalytic Activity ◽  
Quantum Dot ◽  
Colorimetric Detection ◽  
Graphene Quantum Dots ◽  
Functionalized Graphene ◽  
Graphene Quantum Dot ◽  
Nickel Silver

The paper reports the synthesis of nickel-silver-graphene quantum dot-graphene hybrid. Histidine-functionalized graphene quantum dots (His-GQDs) were bonded to graphene oxide (GO) and then combined with Ni2+ and Ag+ to form...

Tumor Cell-Specific Nuclear Targeting of Functionalized Graphene Quantum Dots In Vivo

2017 ◽  
Vol 28 (10) ◽  
pp. 2608-2619 ◽  
Author(s):  
Chenjie Yao ◽  
Yusong Tu ◽  
Lin Ding ◽  
Chenchen Li ◽  
Jiao Wang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Tumor Cell ◽  
Graphene Quantum Dots ◽  
Functionalized Graphene ◽  
Nuclear Targeting

L-cysteine functionalized graphene quantum dots for sub-ppb detection of As (III)

2021 ◽  
Author(s):  
Md. Farhan Naseh ◽  
Neelam Singh ◽  
Jamilur R. Ansari ◽  
Ashavani Kumar ◽  
Tapan Sarkar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Quantum Dots ◽  
Room Temperature ◽  
Graphene Quantum Dots ◽  
Optical Characterization ◽  
Functionalized Graphene ◽  
Transmission Electron ◽  
Sensitivity And Selectivity ◽  
Structural Characterizations

Abstract Here, we report functionalized graphene quantum dots (GQDs) for the optical detection of arsenic at room temperature. GQDs with the fluorescence of three fundamental colors (red, green, and blue) were synthesized and functionally capped with L-cysteine (L-cys) to impart selectively towards As (III) by exploiting the affinity of L-cys towards arsenite. The optical characterization of GQDs was carried out using UV-Vis absorption spectroscopy, Fourier transform infrared spectroscopy, and fluorescence spectrometry and the structural characterizations were performed using transmission electron microscopy. The fluorescence results showed instantaneous quenching in intensity when the GQDs came in contact with As (III) for all test concentrations over a range from 0.025 ppb to 25 ppb, which covers the permissible limit of arsenic in drinking water. The experimental results suggested excellent sensitivity and selectivity towards As (III).

Functionalized graphene quantum dots as a fluorescent “off–on” nanosensor for detection of mercury and ethyl xanthate

2017 ◽  
Vol 43 (12) ◽  
pp. 7457-7470 ◽  
Author(s):  
Mohammad Hassan Amini ◽  
Farnoush Faridbod ◽  
Mohammad Reza Ganjali ◽  
Parviz Norouzi
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Functionalized Graphene ◽  
Ethyl Xanthate

Optical and surface plasmon resonance sensing properties for chitosan/carboxyl-functionalized graphene quantum dots thin film

Optik ◽  
2019 ◽  
Vol 178 ◽  
pp. 802-812 ◽  
Author(s):  
Nur Syahira Md Ramdzan ◽  
Yap Wing Fen ◽  
Nur Alia Sheh Omar ◽  
Nur Ain Asyiqin Anas ◽  
Wan Mohd Ebtisyam Mustaqim Mohd Daniyal ◽  
...  
Keyword(s):  
Thin Film ◽  
Quantum Dots ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Graphene Quantum Dots ◽  
Functionalized Graphene ◽  
Sensing Properties
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