Effective removal of Pb(II)/4-nitroaniline/E. faecalis and E. coli pollutants from water by a novel unique graphene quantum dots@gemifloxacin@ double-layered Fe/Al nanocomposite

2022 ◽  
Vol 46 ◽  
pp. 102562
Author(s):  
Mohamed E. Mahmoud ◽  
Nesma A. Fekry ◽  
Sally M.S. Mohamed
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
E Coli ◽  
Effective Removal

scholarly journals Conjugation of Carboxylated Graphene Quantum Dots with Cecropin P1 for Bacterial Biosensing Applications

2020 ◽  
Author(s):  
Jonathan Bruce ◽  
Jude Clapper
Keyword(s):  
Quantum Dots ◽  
Structural Modification ◽  
Light Emission ◽  
Limit Of Detection ◽  
Graphene Quantum Dots ◽  
Strong Light ◽  
E Coli ◽  
Cecropin P1 ◽  
Compact Field ◽  
Test Kit

<p>Quantum dots have proven to be strong candidates for biosensing applications in recent years, due to their strong light emission properties and their ability to be modified with a variety of functional groups for the detection of different analytes. Here, we investigate the use of conjugated carboxylated graphene quantum dots (CGQDs) for the detection of <i>E. coli</i>, using a biosensing procedure that focuses on measuring changes in fluorescence quenching. We have also further developed this biosensing assay into a compact, field-deployable test kit focused on rapidly measuring changes in absorbance to determine bacterial concentration. Our CGQDs were conjugated with cecropin P1, a naturally-produced antibacterial peptide that facilitates the attachment of CGQDs to <i>E. coli</i> cells. We also confirm the structural modification of these conjugated CGQDs in addition to analyzing their optical characteristics. Our findings have the potential to be used in situations where rapid, reliable detection of bacteria in liquids, such as drinking water, is required, especially given our biosensor’s relatively low observed limit of detection (LOD).</p><br>

Size-Dependent Antibacterial Behavior of Graphene Quantum Dots

2013 ◽  
Author(s):  
Siheng Su ◽  
Carla B. Shelton ◽  
Jingjing Qiu
Keyword(s):  
Quantum Dots ◽  
Surface Chemistry ◽  
Graphene Quantum Dots ◽  
Gel Filtration ◽  
Filtration Method ◽  
E Coli ◽  
Size Dependent ◽  
Mtt Method ◽  
Diphenyltetrazolium Bromide ◽  
Standard Plate

In this study, the antibacterial behavior of differing sized graphene quantum dots (GQDs) was studied. The gram negative bacteria, Escherichia coli (E. coli), were used as the bacteria mode. Different sized GQDs with tunable fluorescent colors were acquired by a gel-filtration method. The size, surface chemistry, and photoluminescence properties of GQDs were characterized, respectively. The viability of GQDs treated bacteria was determined by the standard plate counting method. Moreover, the reactive oxidative species (ROS) level was detected by the 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) method. The integrality of the bacteria membrane was observed under the scanning electron microscopy (SEM). The experimental results indicated that GQDs demonstrated size-dependent and surface chemistry-dependent antibacterial behaviors. This research provided insightful guidelines in the selection of suitable GQDs for their potential bioapplications.

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.

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 Conjugation of Carboxylated Graphene Quantum Dots with Cecropin P1 for Bacterial Biosensing Applications

2020 ◽  
Author(s):  
Jonathan Bruce ◽  
Jude Clapper
Keyword(s):  
Quantum Dots ◽  
Structural Modification ◽  
Light Emission ◽  
Limit Of Detection ◽  
Graphene Quantum Dots ◽  
Strong Light ◽  
E Coli ◽  
Cecropin P1 ◽  
Compact Field ◽  
Test Kit

<p>Quantum dots have proven to be strong candidates for biosensing applications in recent years, due to their strong light emission properties and their ability to be modified with a variety of functional groups for the detection of different analytes. Here, we investigate the use of conjugated carboxylated graphene quantum dots (CGQDs) for the detection of <i>E. coli</i>, using a biosensing procedure that focuses on measuring changes in fluorescence quenching. We have also further developed this biosensing assay into a compact, field-deployable test kit focused on rapidly measuring changes in absorbance to determine bacterial concentration. Our CGQDs were conjugated with cecropin P1, a naturally-produced antibacterial peptide that facilitates the attachment of CGQDs to <i>E. coli</i> cells. We also confirm the structural modification of these conjugated CGQDs in addition to analyzing their optical characteristics. Our findings have the potential to be used in situations where rapid, reliable detection of bacteria in liquids, such as drinking water, is required, especially given our biosensor’s relatively low observed limit of detection (LOD).</p><br>

scholarly journals Conjugation of Carboxylated Graphene Quantum Dots with Cecropin P1 for Bacterial Biosensing Applications

2020 ◽  
Author(s):  
Jonathan Bruce ◽  
Jude Clapper
Keyword(s):  
Quantum Dots ◽  
Drinking Water ◽  
Structural Modification ◽  
Light Emission ◽  
Limit Of Detection ◽  
Graphene Quantum Dots ◽  
Strong Light ◽  
E Coli ◽  
Cecropin P1 ◽  
Reliable Detection

<p>Quantum dots have proven to be strong candidates for biosensing applications in recent years, due to their strong light emission properties and their ability to be modified with a variety of functional groups for the detection of different analytes. Here, we investigate the use of conjugated carboxylated graphene quantum dots (CGQDs) for the detection of <i>E. coli</i>, using a biosensing procedure that focuses on measuring changes in fluorescence quenching. Our CGQDs were conjugated with cecropin P1, a naturally-produced antibacterial peptide that facilitates the attachment of CGQDs to <i>E. coli</i> cells. We also confirm the structural modification of these conjugated CGQDs in addition to analyzing their optical characteristics. Our findings have the potential to be used in situations where rapid, reliable detection of bacteria in liquids, such as drinking water, is required, especially given our biosensor’s relatively low observed limit of detection (LOD).</p><br>

Preparation of Graphene Quantum Dots and Their Biological Applications

2016 ◽  
Vol 31 (4) ◽  
pp. 337 ◽  
Author(s):  
SUN Xiao-Dan ◽  
LIU Zhong-Qun ◽  
YAN Hao
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Biological Applications
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