scholarly journals One-Step Synthesis of Diamine-Functionalized Graphene Quantum Dots from Graphene Oxide and Their Chelating and Antioxidant Activities

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 104 ◽  
Author(s):  
Rabeb El-Hnayn ◽  
Laetitia Canabady-Rochelle ◽  
Christophe Desmarets ◽  
Lavinia Balan ◽  
Hervé Rinnert ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Oxide ◽  
Colloidal Stability ◽  
Antioxidant Activities ◽  
Graphene Quantum Dots ◽  
Average Diameter ◽  
Functionalized Graphene ◽  
One Step ◽  
Low Cytotoxicity ◽  
Health Applications

2,2’-(Ethylenedioxy)bis(ethylamine)-functionalized graphene quantum dots (GQDs) were prepared under mild conditions from graphene oxide (GO) via oxidative fragmentation. The as-prepared GQDs have an average diameter of ca. 4 nm, possess good colloidal stability, and emit strong green-yellow light with a photoluminescence (PL) quantum yield of 22% upon excitation at 375 nm. We also demonstrated that the GQDs exhibit high photostability and the PL intensity is poorly affected while tuning the pH from 1 to 8. Finally, GQDs can be used to chelate Fe(II) and Cu(II) cations, scavenge radicals, and reduce Fe(III) into Fe(II). These chelating and reducing properties that associate to the low cytotoxicity of GQDs show that these nanoparticles are of high interest as antioxidants for health applications.

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...

High-Purity Amino-Functionalized Graphene Quantum Dots Derived from Graphene Hydrogel

NANO ◽  
2016 ◽  
Vol 11 (12) ◽  
pp. 1650138 ◽  
Author(s):  
Yinhua Jin ◽  
Hongyi Qin ◽  
Jang Ah Kim ◽  
Sun-Young Kim ◽  
Hyeong-U Kim ◽  
...  
Keyword(s):  
Quantum Dots ◽  
High Purity ◽  
Hydrothermal Reaction ◽  
Graphene Quantum Dots ◽  
Synthesis Method ◽  
Water Soluble ◽  
Synthesis Process ◽  
Functionalized Graphene ◽  
Ultrasonic Probe ◽  
Low Cytotoxicity

The unique properties of graphene quantum dots (GQDs) make them interesting candidate materials for innovative applications. Herein, we report a facile method to synthesize amino-functionalized graphene quantum dots (AF-GQDs) by a hydrothermal reaction. Graphene oxide (GO) was synthesized by Hummer’s method where ultra-small GO sheets were obtained by a prolonged oxidation process followed by sonication using an ultrasonic probe. Subsequently, graphene hydrogel (GH) was also obtained by a hydrothermal synthesis method. Proper care was taken during synthesis to avoid contamination from water soluble impurities, which are present in the precursor, GO solution. Following the treatment of GH in ammonia, ultra-small amino-functionalized graphene fragments (AF-GQDs) were formed, which detached from the GH to eventually disperse evenly in the water without agglomerating. This modified synthesis process enables the formation of high-purity AF-GQDs (99.14%) while avoiding time-consuming synthesis procedures. Our finding shows that AF-GQDs with sizes less than 5[Formula: see text]nm were well dispersed. A strong photoluminescence (PL) emission at [Formula: see text]410[Formula: see text]nm with 10% PL quantum yield was also observed. These AF-GQDs can be used in many bio applications in view of their low cytotoxicity and strong fluorescence that can be applied to cell imaging.

scholarly journals Graphene Oxide and Graphene Quantum Dots as Delivery Systems of Cationic Porphyrins: Photo-Antiproliferative Activity Evaluation towards T24 Human Bladder Cancer Cells

Pharmaceutics ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1512
Author(s):  
Luca Menilli ◽  
Ana R. Monteiro ◽  
Silvia Lazzarotto ◽  
Filipe M. P. Morais ◽  
Ana T. P. C. Gomes ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Bladder Cancer ◽  
Graphene Oxide ◽  
Apoptotic Cell ◽  
Red Light ◽  
Graphene Quantum Dots ◽  
Oxygen Generation ◽  
Bladder Cancer Cells ◽  
One Step

The development of new photodynamic therapy (PDT) agents designed for bladder cancer (BC) treatments is of utmost importance to prevent its recurrence and progression towards more invasive forms. Here, three different porphyrinic photosensitizers (PS) (TMPyP, Zn-TMPyP, and P1-C5) were non-covalently loaded onto graphene oxide (GO) or graphene quantum dots (GQDs) in a one-step process. The cytotoxic effects of the free PS and of the corresponding hybrids were compared upon blue (BL) and red-light (RL) exposure on T24 human BC cells. In addition, intracellular reactive oxygen species (ROS) and singlet oxygen generation were measured. TMPyP and Zn-TMPyP showed higher efficiency under BL (IC50: 0.42 and 0.22 μm, respectively), while P1-C5 was more active under RL (IC50: 0.14 μm). In general, these PS could induce apoptotic cell death through lysosomes damage. The in vitro photosensitizing activity of the PS was not compromised after their immobilization onto graphene-based nanomaterials, with Zn-TMPyP@GQDs being the most promising hybrid system under RL (IC50: 0.37 μg/mL). Overall, our data confirm that GO and GQDs may represent valid platforms for PS delivery, without altering their performance for PDT on BC cells.

One-step ultrasonic synthesis of graphene quantum dots with high quantum yield and their application in sensing alkaline phosphatase

2015 ◽  
Vol 51 (5) ◽  
pp. 948-951 ◽  
Author(s):  
Yanhong Zhu ◽  
Guangfeng Wang ◽  
Hong Jiang ◽  
Ling Chen ◽  
Xiaojun Zhang
Keyword(s):  
Quantum Dots ◽  
Alkaline Phosphatase ◽  
Graphene Oxide ◽  
Quantum Yield ◽  
Graphene Quantum Dots ◽  
Label Free ◽  
High Quantum Yield ◽  
Ultrasonic Synthesis ◽  
High Quantum ◽  
One Step

With only graphene oxide and KMnO4, the luminescent graphene quantum dots (GQDs) in high quantum yield were prepared by one-step synthesis using ultrasonication, and applied in the label-free, simple and fast fluorescence assay of alkaline phosphatase (ALP).

NiCo2S4/tryptophan-functionalized graphene quantum dot nanohybrids for high-performance supercapacitors

2017 ◽  
Vol 41 (3) ◽  
pp. 1110-1118 ◽  
Author(s):  
Huiying Wang ◽  
Yongqiang Yang ◽  
Xiaoyan Zhou ◽  
Ruiyi Li ◽  
Zaijun Li
Keyword(s):  
Quantum Dots ◽  
Electrochemical Performance ◽  
High Performance ◽  
Hydrothermal Reaction ◽  
Graphene Quantum Dots ◽  
Functionalized Graphene ◽  
Facile Synthesis ◽  
Graphene Quantum Dot ◽  
One Step ◽  
Enhanced Electrochemical Performance

This paper reports a facile synthesis of NiCo2S4via a one-step hydrothermal reaction and its hybrid with tryptophan-functionalized graphene quantum dots. The nanohybrid electrode exhibits significantly enhanced electrochemical performance for supercapacitors.

One-Step Preparation of Green Fluorescent Graphene Quantum Dots from Petroleum Asphalt

2017 ◽  
Vol 45 ◽  
pp. 76-83 ◽  
Author(s):  
Pin Hui Zhao ◽  
Yi Luo ◽  
Ling Yun Kong
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Green Light ◽  
Average Diameter ◽  
Chemical Oxidation ◽  
Fluorescent Properties ◽  
Petroleum Asphalt ◽  
One Step ◽  
Bright Green ◽  
Green Fluorescent

Inherently benefiting from the natural nanosize graphene-structure in raw asphalt material. Asphalt-derived graphene quantum dots ( GQDs ) are prepared through, a facile route, one-step chemical oxidation of cheap petroleum asphalt. The as-prepared GQD sample may be well dissolved in water with a good homogeneous size at an average diameter of 2.44 nm, luminescing bright green light by excitation of 365 nm with a high quantum yield up to 16.13%. Furthermore, they are much smaller and thinner than most of the reported GQDs, presenting excellent fluorescent properties, such as excitation-tuned photoluminescence and good resistance to photobleaching. They are much smaller and thinner than most of the reported GQDs

Tailoring of ammonia reduced graphene oxide into amine functionalized graphene quantum dots through a Hofmann rearrangement

RSC Advances ◽  
2016 ◽  
Vol 6 (41) ◽  
pp. 34514-34520 ◽  
Author(s):  
Yongqiang Dai ◽  
Hao Pang ◽  
Jianheng Huang ◽  
Yong Yang ◽  
Hao Huang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Graphene Quantum Dots ◽  
Functionalized Graphene ◽  
Hofmann Rearrangement ◽  
Amine Functionalized ◽  
Reduced Graphene

A Hofmann rearrangement tailored and exfoliated multi-layered ammonia reduced graphene oxide into amine functionalized graphene quantum dots.

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