Oxidation degree or sheet size: What really matters for the photothermal effect and ecotoxicity of graphene oxide?

FlatChem ◽  
2021 ◽  
Vol 26 ◽  
pp. 100231
Author(s):  
Caio C.C. Moreira ◽  
Ítalo A. Costa ◽  
Diego S. Moura ◽  
Cesar K. Grisolia ◽  
Carlos A.E.M. Leite ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Photothermal Effect ◽  
Oxidation Degree

scholarly journals Photothermal-assisted antibacterial application of GO-Ag against clinical isolated MDR E. coli

2019 ◽  
Author(s):  
Yuqing Chen ◽  
Wei Wu ◽  
Zeqiao Xu ◽  
Cheng Jiang ◽  
Shuang Han ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Near Infrared ◽  
Antibacterial Effect ◽  
Luria Bertani ◽  
Fluorescent Imaging ◽  
Photothermal Effect ◽  
Antibacterial Efficiency ◽  
E Coli ◽  
Morphology Characterization

Abstract Background: Treatment of multidrug-resistant (MDR) bacterial infection is a great challenge in public health. Herein, we provide a solution to this problem with the use of graphene oxide-silver (GO-Ag) nanocomposites as anti-bacterial agent. Methods: Following established protocols, silver nanoparticles were grown on graphene oxide sheets. Then, a series of in-vitro studies were conducted to validate the antibacterial efficiency of the GO-Ag nanocomposites against clinical MDR Escherichia coli (E. coli) strains. Firstly, minimum inhibitory concentrations (MICs) of different antimicrobials were tested against MDR E. Coli strains. Then, bacteria viability assessments were conducted with different nanomaterials in Luria-Bertani (LB) broth. Afterwards, photothermal irradiation was conducted on MDR E. coli with lower GO-Ag concentration. At last, fluorescent imaging and morphology characterization using scanning electron microscope (SEM) were done to find the possible cause of antibacterial effect. Results: GO-Ag nanocomposites showed the highest antibacterial efficiency among tested antimicrobials. Synergetic antibacterial effect was observed in GO-Ag nanocomposites treated group. The remained bacteria viabilities were 4.4% and 4.1% respectively for different bacteria strains with GO-Ag concentration at 14.0 µg mL-1. In addition, GO-Ag nanocomposites have strong absorption in the near-infrared field and can convert the electromagnetic energy to heat. With the use of this photothermal effect, effective sterilization could be achieved using GO-Ag nanocomposites concentration as low as 7.0 µg mL-1. Fluorescent imaging and morphology characterization were used to analyze bacteria living status, which uncovered that bacteria integrity was disrupted after GO-Ag nanocomposites treatment. Conclusions: GO-Ag nanocomposites are proved to be efficient antibacterial agent against multi-drug resistant E. coli. Their strong antibacterial effect arises from inherent antibacterial property and photothermal effect that provides aid for bacteria killing.

Tailoring thermal conductivity of bulk graphene oxide by tuning the oxidation degree

2018 ◽  
Vol 29 (5) ◽  
pp. 711-715 ◽  
Author(s):  
Qing-Long Meng ◽  
Hengchang Liu ◽  
Zhiwei Huang ◽  
Shuang Kong ◽  
Peng Jiang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Graphene Oxide ◽  
Oxidation Degree

scholarly journals Influence of Oxidation Degree of Graphene Oxide on Its Nuclear Relaxivity and Contrast in MRI

ACS Omega ◽  
2020 ◽  
Vol 5 (35) ◽  
pp. 22131-22139
Author(s):  
Zinia Mohanta ◽  
Sumana K. Gaonkar ◽  
Manoj Kumar ◽  
Jitender Saini ◽  
Vivek Tiwari ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Oxidation Degree

scholarly journals Influence of Oxidation Degree of Graphene Oxide on the Shear Rheology of Poly(ethylene glycol) Suspensions

Fluids ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 41 ◽  
Author(s):  
Yago Soares ◽  
Elyff Cargnin ◽  
Mônica Naccache ◽  
Ricardo Andrade
Keyword(s):  
Graphene Oxide ◽  
Rheological Behavior ◽  
Structural Characteristics ◽  
Rheological Characterization ◽  
Polymeric Liquid ◽  
Oxidation Degree ◽  
Force Microscopy ◽  
Fluid Behavior ◽  
Atomic Force ◽  
Poly Ethylene

This work studies the influence of the concentration and oxidation degree on the rheological behavior of graphene oxide (GO) nanosheets dispersed on polyethylene glycol (PEG). The rheological characterization was fulfilled in shear flow through rotational rheometry measurements, in steady, transient and oscillatory regimes. Graphene oxide was prepared by chemical exfoliation of graphite using the modified Hummers method. The morphological and structural characteristics originating from the synthesis were analyzed by X-ray diffraction, Raman spectroscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, and atomic force microscopy. It is shown that higher oxidation times increase the functional groups, which leads to a higher dispersion and exfoliation of GO sheets in the PEG. Moreover, the addition of GO in a PEG solution results in significant growth of the suspension viscosity, and a change of the fluid behavior from Newtonian to pseudoplastic. This effect is related to the concentration and oxidation level of the obtained GO particles. The results obtained aim to contribute towards the understanding of the interactions between the GO and the polymeric liquid matrix, and their influence on the suspension rheological behavior.

The Correlation Between Molecular Structure and Tribological Properties of Graphene Oxide with Different Oxidation Degree

2019 ◽  
Vol 67 (3) ◽  
Author(s):  
Lei Zhao ◽  
Hongmei Yang ◽  
Chang Liu ◽  
Shaoqing Xue ◽  
Zhao Deng ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Graphene Oxide ◽  
Tribological Properties ◽  
Oxidation Degree
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