Optimizing oxygen functional groups in graphene quantum dots for improved antioxidant mechanism

2019 ◽  
Vol 21 (3) ◽  
pp. 1336-1343 ◽  
Author(s):  
Yingmin Wang ◽  
Wenhui Kong ◽  
Lifeng Wang ◽  
Jin Zhong Zhang ◽  
Yan Li ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Free Radicals ◽  
Functional Groups ◽  
Graphene Quantum Dots ◽  
Antioxidant Mechanism ◽  
Oxygen Functional Groups

The development of new antioxidants with quick absorbance of free radicals and excellent biocompatibility has drawn intensive attention in recent years.

How functional groups influence the ROS generation and cytotoxicity of graphene quantum dots

2017 ◽  
Vol 53 (76) ◽  
pp. 10588-10591 ◽  
Author(s):  
Ya Zhou ◽  
Hanjun Sun ◽  
Faming Wang ◽  
Jinsong Ren ◽  
Xiaogang Qu
Keyword(s):  
Quantum Dots ◽  
Functional Groups ◽  
Graphene Quantum Dots ◽  
Ros Generation ◽  
Hydroxyl Groups ◽  
Carbonyl Groups ◽  
Oxygen Functional Groups

Herein we selectively deactivate the ketonic carbonyl, carboxylic, or hydroxyl groups on GQDs and compare their ROS generation ability. The ROS generation ability of GQDs is closely related to these oxygen functional groups, especially for the ketonic carbonyl groups.

scholarly journals Antioxidant Activity of Graphene Quantum Dots Prepared in Different Electrolyte Environments

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1708 ◽  
Author(s):  
Lin Zhao ◽  
Yingmin Wang ◽  
Yan Li
Keyword(s):  
Quantum Dots ◽  
Antioxidant Activity ◽  
Free Radicals ◽  
Water Solubility ◽  
Radical Scavenging Activity ◽  
Graphene Quantum Dots ◽  
Radical Scavenging ◽  
Effective Control ◽  
Antioxidant Mechanism ◽  
Scavenging Efficiency

Antioxidants can reduce or inhibit damage such as oxidative decay caused by elevated levels of free radicals. Therefore, pursuing antioxidants with excellent properties has attracted more and more attention. Graphene quantum dots (GQDs) are considered a promising material because of their good free radical scavenging activity, low toxicity, and excellent water solubility. However, their scavenging efficiency, antioxidant mechanism, and effective control methods need to be improved. Herein, in order to further reveal the antioxidant mechanism of GQDs, the role of electrolytes in improving the antioxidant activity of GQDs is explored. In addition, 1,1-diphenyl-2-picrazine (DPPH∙), hydroxyl (∙OH), and superoxide (∙O2−) free radicals are used to evaluate the antioxidant activity of the as-prepared GQDs. Combined with transmission electron microscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, and cyclic volt–ampere characteristic curves, the effects of an electrolytic environment on the surface functional groups, charge transfer capability, and defect states of GQDs are obtained. The antioxidant mechanism of GQDs and how to improve their antioxidant activity are further elucidated.

scholarly journals Cellular distribution and cytotoxicity of graphene quantum dots with different functional groups

2014 ◽  
Vol 9 (1) ◽  
pp. 108 ◽  
Author(s):  
Xiaochan Yuan ◽  
Zhiming Liu ◽  
Zhouyi Guo ◽  
Yanhong Ji ◽  
Mei Jin ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Functional Groups ◽  
Graphene Quantum Dots ◽  
Cellular Distribution

scholarly journals Quantum Yield Enhancement in Graphene Quantum Dots via Esterification with Benzyl Alcohol

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Suzuka Tachi ◽  
Hiroki Morita ◽  
Misaki Takahashi ◽  
Yusuke Okabayashi ◽  
Takuya Hosokai ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Yield ◽  
Benzyl Alcohol ◽  
Functional Groups ◽  
Photophysical Properties ◽  
Graphene Quantum Dots ◽  
Yield Enhancement ◽  
Light Illumination ◽  
Nonradiative Recombination ◽  
Widespread Application

Abstract The quantum yield of graphene quantum dots was enhanced by restriction of the rotation and vibration of surface functional groups on the edges of the graphene quantum dots via esterification with benzyl alcohol; this enhancement is crucial for the widespread application of graphene quantum dots in light-harvesting devices and optoelectronics. The obtained graphene quantum dots with highly graphene-stacked structures are understood to participate in π–π interactions with adjacent aromatic rings of the benzylic ester on the edges of the graphene quantum dots, thus impeding the nonradiative recombination process in graphene quantum dots. Furthermore, the crude graphene quantum dots were in a gel-like solid form and showed white luminescence under blue light illumination. Our results show the potential for improving the photophysical properties of nanomaterials, such as the quantum yield and band-gap energy for emission, by controlling the functional groups on the surface of graphene quantum dots through an organic modification approach.

Folic acid-functionalized graphene quantum dots with tunable fluorescence emission for cancer cell imaging and optical detection of Hg2+

2018 ◽  
Vol 42 (6) ◽  
pp. 4352-4360 ◽  
Author(s):  
Ruiyi Li ◽  
Xuan Wang ◽  
Zaijun Li ◽  
Haiyan Zhu ◽  
Junkang Liu
Keyword(s):  
Quantum Dots ◽  
Folic Acid ◽  
Functional Groups ◽  
Cancer Cell ◽  
Cell Imaging ◽  
Optical Detection ◽  
Graphene Quantum Dots ◽  
Fluorescence Emission ◽  
Electrical Characteristics ◽  
Functionalized Graphene

Functional groups may alter the optical and electrical characteristics of graphene quantum dots and lead to unusual properties and related applications.

Insight into the effect of functional groups on visible-fluorescence emissions of graphene quantum dots

2016 ◽  
Vol 4 (11) ◽  
pp. 2235-2242 ◽  
Author(s):  
Jianglin Du ◽  
Haiyu Wang ◽  
Lei Wang ◽  
Shoujun Zhu ◽  
Yubin Song ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Functional Groups ◽  
Graphene Quantum Dots ◽  
Light Emitting ◽  
Insight Into

Various functional groups in graphene quantum dots may play critical roles in their fluorescent emissions, and different groups contribute to different light-emitting wavelengths.

Nitrogen-Doped Graphene Quantum Dots with Oxygen-Rich Functional Groups

2011 ◽  
Vol 134 (1) ◽  
pp. 15-18 ◽  
Author(s):  
Yan Li ◽  
Yang Zhao ◽  
Huhu Cheng ◽  
Yue Hu ◽  
Gaoquan Shi ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Functional Groups ◽  
Graphene Quantum Dots ◽  
Nitrogen Doped ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene
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