Highly Oxidized Graphene Quantum Dots from Coal as Efficient Antioxidants

Nilewski, Christian; Mendoza, Kimberly; Jalilov, Almaz S.; Berka, Vladimír; Wu, Gang; Sikkema, William K.A.; Metzger, Andrew; Ye, Ruquan; Zhang, Rui; Luong, Duy Xuan; Wang, Tuo; McHugh, Emily A.; Derry, Paul J.; Samuel, Errol L. G.; Kent, Thomas A.; Tsai, Alan C.; Tour, James M.

doi:10.1021/acsami.9b01082

Cited by 64 publications

(56 citation statements)

References 30 publications

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“…Here, we report first a mild and one-step synthesis of 2,2'-(ethylenedioxy)bis(ethylamine)functionalized GQDs via amine-assisted cutting of GO while using hydrogen peroxide H 2 O 2 at 80 • C. The green-yellow emitting GQDs that were obtained exhibit a high PL quantum yield of 22% and a PL emission wavelength dependent on the excitation wavelength. Next, we demonstrate that GQDs could trap Fe(II) and Cu(II) ions and scavenge radicals like the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS •+ ) due to their reducing activity, owing to the radical scavenging properties of the sp 2 -carbon domains [42][43][44][45][46][47][48] and the chelation ability of both oxygen-containing functions and of the 2,2'-(ethylenedioxy)bis(ethylamine) moieties [49][50][51].…”

Section: Introductionmentioning

confidence: 92%

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

et al. 2020

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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.

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Section: Introductionmentioning

confidence: 92%

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

et al. 2020

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“…Химическая модификация ОГ (допирование азотом, введение различных функциональных групп) существенно увеличивает его антиоксидантную активность [13], в связи с этим можно предположить, что пегилирование оказывает влияние на нейтрализацию АФК ОГ, однако Nilewski и соавт. [9] [8]. Это говорит о возможности того, что эффекты ОГ могут проявляться почти мгновенно.…”

Section: Discussionunclassified

Study of the graphene oxide nanoparticles effect on luminol-dependent chemiluminescence of human leukocytes

et al. 2020

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Graphene and its derivatives are increasingly used in biomedical research. Therefore, the mechanisms and consequences of the interaction of graphene nanoparticles with living objects are intensively studied. The immune system is involved in protecting the body and regulating its functions, so the question of the effect of graphene and its derivatives on immune cells is crucial. The specific response of monocytes, macrophages, and neutrophils to a stimulus is to increase the production of reactive oxygen species (ROS). Published data on graphene oxide (GO) and polyethylene glycol-modified graphene oxide (GO-PEG) effects on peripheral blood leukocytes are scarce and contradictory. It is due to variations in objects and conditions of study, along with the difference in particle concentrations. Thus, it was essential to evaluate the GO and GO-PEG effect on ROS production by human leukocytes. Our study aimed at the effect of particles of unmodified and PEG-modified graphene oxide (GO and GO-PEG) on the ROS production by peripheral blood leukocytes in not-stimulated and stimulated luminoldependent chemiluminescence (LCL) tests. ROS production was stimulated by opsonized zymosan (OZ). A hydrogen peroxide-luminol system was used for assessing the independent effect of GO nanoparticles on the quenching of ROS luminescence. Pristine GO (Ossila, Great Britain) nanoparticles were PEG-modified (GO-PEG). The average size of the GO flakes was 1-5 µm, the GO-PEG-flakes 569±14 nm, and the amount of PEG covering was ~ 20%. Nanoparticles were used at concentrations of 5; 2.5; 1.25 µg/ml. It has been established that GO-PEG nanoparticles in concentrations of 2.5 and 5 µg/ml suppressed ROS production in the spontaneous LCL test. At the same time, the GO effects showed a visible but a not significant tendency to inhibition of LCL. Similar results were obtained in the stimulated LCL test. However, when analyzing the process kinetics, both GO-PEG and GO decreased the ROS production, but mainly in the first minutes of the test. When analyzing the quenching effect of the LCL reaction in a cell-free system, there was no significant effect of GO and GO-PEG nanoparticles. Thus, the general vector of the obtained effects was associated with the suppression of ROS production. GO-PEG ROS-decreasing effects were more pronounced in comparison with unmodified GO. In general, we have confirmed the antioxidant effects of GO and GO-PEG using the LCL method. We can assume that in addition to the actual antioxidant effect of graphene nanoparticles, ROS production decreases due to the rapid GO uptake and blocking of several intracellular signals that induce an oxidative burst.

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“…1e). 27 The GQDs obtained by the improved synthesis method have high crystallinity and good solubility in both water and organic solvents. In 2016, Zhang et al prepared GQDs with a grain diameter of 4-10 nm by using an ultrasonic-assisted chemical stripping method and using O 3 and H 2 O 2 to conduct oxidation cutting of GO.…”

Section: Top-down Methodsmentioning

confidence: 99%

Graphene quantum dots for energy storage and conversion: from fabrication to applications

Liu

Sun

Gao

et al. 2020

Mater. Chem. Front.

105

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Highly Oxidized Graphene Quantum Dots from Coal as Efficient Antioxidants

Cited by 64 publications

References 30 publications

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

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

Study of the graphene oxide nanoparticles effect on luminol-dependent chemiluminescence of human leukocytes

Graphene quantum dots for energy storage and conversion: from fabrication to applications

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