Chemical reduction of graphene enhances in vivo translocation and photosynthetic inhibition in pea plants

2019 ◽  
Vol 6 (4) ◽  
pp. 1077-1088 ◽  
Author(s):  
Lingyun Chen ◽  
Chenglong Wang ◽  
Shengnan Yang ◽  
Xin Guan ◽  
Qiangqiang Zhang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Photosystem Ii ◽  
Reduced Graphene Oxide ◽  
Chemical Reduction ◽  
Oxygen Evolving Complex ◽  
Donor Side ◽  
Photosynthetic Inhibition ◽  
Reduced Graphene ◽  
Oxygen Evolving

Reduced graphene oxide (RGO) was translocated into leaves and inhibited the activity of photosystem II by damaging the oxygen-evolving-complex on the donor side.

Quantitative assessment of the high-light tolerance in plants with an impaired photosystem II donor side

2019 ◽  
Vol 476 (9) ◽  
pp. 1377-1386 ◽  
Author(s):  
Sam Wilson ◽  
Alexander V. Ruban
Keyword(s):  
Photosystem Ii ◽  
Redox State ◽  
Photochemical Quenching ◽  
Oxygen Evolving Complex ◽  
Reaction Centre ◽  
Donor Side ◽  
Acceptor Side ◽  
Oxygen Evolving ◽  
The Impact

Abstract Photoinhibition is the light-induced down-regulation of photosynthetic efficiency, the primary target of which is photosystem II (PSII). Currently, there is no clear consensus on the exact mechanism of this process. However, it is clear that inhibition can occur through limitations on both the acceptor- and donor side of PSII. The former mechanism is caused by electron transport limitations at the PSII acceptor side. Whilst, the latter mechanism relies on the disruption of the oxygen-evolving complex. Both of these mechanisms damage the PSII reaction centre (RC). Using a novel chlorophyll fluorescence methodology, RC photoinactivation can be sensitively measured and quantified alongside photoprotection in vivo. This is achieved through estimation of the redox state of QA, using the parameter of photochemical quenching in the dark (qPd). This study shows that through the use of PSII donor-side inhibitors, such as UV-B and Cd2+, there is a steeper gradient of photoinactivation in the systems with a weakened donor side, independent of the level of NPQ attained. This is coupled with a concomitant decline in the light tolerance of PSII. The native light tolerance is partially restored upon the use of 1,5-diphenylcarbazide (DPC), a PSII electron donor, allowing for the balance between the inhibitory pathways to be sensitively quantified. Thus, this study confirms that the impact of donor-side inhibition can be detected alongside acceptor-side photoinhibition using the qPd parameter and confirms qPd as a valid, sensitive and unambiguous parameter to sensitively quantify the onset of photoinhibition through both acceptor- or donor-side mechanisms.

scholarly journals Biomimetic reduced graphene oxide coated collagen scaffold for in situ bone regeneration

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sajad Bahrami ◽  
Nafiseh Baheiraei ◽  
Mostafa Shahrezaee
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Cranial Bone ◽  
Drying Methods ◽  
Porous Scaffolds ◽  
Alizarin Red ◽  
Reduced Graphene ◽  
Coated Collagen

AbstractA variety of bone-related diseases and injures and limitations of traditional regeneration methods require new tissue substitutes. Tissue engineering and regeneration combined with nanomedicine can provide different natural or synthetic and combined scaffolds with bone mimicking properties for implantation in the injured area. In this study, we synthesized collagen (Col) and reduced graphene oxide coated collagen (Col-rGO) scaffolds, and we evaluated their in vitro and in vivo effects on bone tissue repair. Col and Col-rGO scaffolds were synthesized by chemical crosslinking and freeze-drying methods. The surface topography, and the mechanical and chemical properties of scaffolds were characterized, showing three-dimensional (3D) porous scaffolds and successful coating of rGO on Col. The rGO coating enhanced the mechanical strength of Col-rGO scaffolds to a greater extent than Col scaffolds by 2.8 times. Furthermore, Col-rGO scaffolds confirmed that graphene addition induced no cytotoxic effects and enhanced the viability and proliferation of human bone marrow-derived mesenchymal stem cells (hBMSCs) with 3D adherence and expansion. Finally, scaffold implantation into rabbit cranial bone defects for 12 weeks showed increased bone formation, confirmed by Hematoxylin–Eosin (H&E) and alizarin red staining. Overall, the study showed that rGO coating improves Col scaffold properties and could be a promising implant for bone injuries.

scholarly journals A Facile and Green Synthesis of a MoO2-Reduced Graphene Oxide Aerogel for Energy Storage Devices

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 594 ◽  
Author(s):  
Mara Serrapede ◽  
Marco Fontana ◽  
Arnaud Gigot ◽  
Marco Armandi ◽  
Glenda Biasotto ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Chemical Reduction ◽  
Low Cost ◽  
Xps Analysis ◽  
3D Scaffold ◽  
Energy Storage Devices ◽  
Reduced Graphene

A simple, low cost, and “green” method of hydrothermal synthesis, based on the addition of l-ascorbic acid (l-AA) as a reducing agent, is presented in order to obtain reduced graphene oxide (rGO) and hybrid rGO-MoO2 aerogels for the fabrication of supercapacitors. The resulting high degree of chemical reduction of graphene oxide (GO), confirmed by X-Ray Photoelectron Spectroscopy (XPS) analysis, is shown to produce a better electrical double layer (EDL) capacitance, as shown by cyclic voltammetric (CV) measurements. Moreover, a good reduction yield of the carbonaceous 3D-scaffold seems to be achievable even when the precursor of molybdenum oxide is added to the pristine slurry in order to get the hybrid rGO-MoO2 compound. The pseudocapacitance contribution from the resulting embedded MoO2 microstructures, was then studied by means of CV and electrochemical impedance spectroscopy (EIS). The oxidation state of the molybdenum in the MoO2 particles embedded in the rGO aerogel was deeply studied by means of XPS analysis and valuable information on the electrochemical behavior, according to the involved redox reactions, was obtained. Finally, the increased stability of the aerogels prepared with l-AA, after charge-discharge cycling, was demonstrated and confirmed by means of Field Emission Scanning Electron Microscopy (FESEM) characterization.

Chemically reduced graphene oxide-coated knitted fabric imparted conductivity and outstanding hydrophobicity

2021 ◽  
pp. 004051752199547
Author(s):  
Min Hou ◽  
Xinghua Hong ◽  
Yanjun Tang ◽  
Zimin Jin ◽  
Chengyan Zhu ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Chemical Reduction ◽  
Knitted Fabric ◽  
Mesh Structure ◽  
Reduced Graphene ◽  
Chemically Reduced Graphene Oxide ◽  
Modified Hummers Method

Functionalized knitted fabric, as a kind of flexible, wearable, and waterproof material capable of conductivity, sensitivity and outstanding hydrophobicity, is valuable for multi-field applications. Herein, the reduced graphene oxide (RGO)-coated knitted fabric (polyester/spandex blended) is prepared, which involves the use of graphite oxide (GO) by modified Hummers method and in-situ chemical reduction with hydrazine hydrate. The treated fabric exhibits a high electrical conductivity (202.09 S/cm) and an outstanding hydrophobicity (140°). The outstanding hydrophobicity is associated with the morphology of the fabric and fiber with reference to pseudo-infiltration. These properties can withstand repeated bending and washing without serious deterioration, maintaining good electrical conductivity (35.70 S/cm) and contact angle (119.39°) after eight standard washing cycles. The material, which has RGO architecture and continuous loop mesh structure, can find wide use in smart garment applications.

scholarly journals Synthesis and Characterization of Reduced Graphene Oxide (rGO) Started from Graphene Oxide (GO) Using the Tour Method with Different Parameters

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Adere Tarekegne Habte ◽  
Delele Worku Ayele
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Potassium Permanganate ◽  
Chemical Reduction ◽  
Volume Ratio ◽  
Graphite Powder ◽  
Green Approach ◽  
Synthesis Strategy ◽  
Reduced Graphene ◽  
Diffraction Patterns

A new approach to synthesize graphene is oxidizing graphite powder with a mixture of H2SO4/H3PO4 acids and potassium permanganate. Parameters such as reaction time, reaction temperature, and amount of concentration were varied to study the degree of oxidation of graphite to graphene oxide. Currently, an improved method for the preparation of graphene oxide was the most common one. A mixture of H2SO4/H3PO4 (9 : 1 volume ratio) instead of only H2SO4 resulted in increased hydrophilic and oxidized GO without the emission of toxic gas, which differs from the traditional Hummers’ method. The graphene oxide (GO) was converted to reduced graphene oxide (rGO) by chemical reduction using ascorbic acid as the reducing agent. The GO and rGO were characterized by UV-visible spectroscopy, FTIR spectroscopy, and X-ray diffraction patterns. The result showed that treating graphite powder with potassium permanganate (1 : 9) and a mixture of concentrated H2SO4/H3PO4 acids at 50°C for 12 hours resulted in a better oxidation degree. The designed synthesis strategy could be easily controlled and is an alternative green approach for the production of graphene oxide and reduced graphene oxide.

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