Chemical Etching of Silicon Assisted by Graphene Oxide in an HF–HNO3 Solution and Its Catalytic Mechanism

Langmuir ◽  
2021 ◽  
Author(s):  
Wataru Kubota ◽  
Toru Utsunomiya ◽  
Takashi Ichii ◽  
Hiroyuki Sugimura
Keyword(s):  
Graphene Oxide ◽  
Chemical Etching ◽  
Catalytic Mechanism ◽  
Hno3 Solution

Design of a graphene oxide-BODIPY conjugate for glutathione depletion and photodynamic therapy

2D Materials ◽  
2021 ◽  
Author(s):  
Giacomo Reina ◽  
Amalia Ruiz ◽  
Barbara Richichi ◽  
Giacomo Biagiotti ◽  
Gina Elena Giacomoazzo ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Photodynamic Therapy ◽  
Cell Viability ◽  
Catalytic Mechanism ◽  
Glutathione Transferase ◽  
Bathochromic Shift ◽  
3D Models ◽  
Glutathione Depletion ◽  
In Vitro Biocompatibility

Abstract Boron dipyrromethene derivates (BODIPYs) are promising photosensitisers (PSs) for cancer treatment using photodynamic therapy (PDT). This study investigates the functionalisation of graphene oxide (GO) with a BODIPY derivate for glutathione (GSH) depletion and PDT. The functionalisation of GO with a 3,5-dichloro-8-(4-boronophenyl) BODIPY via a diol derivatisation with the phenyl boronic acid moiety at the meso position of the BODIPY core, allowed to preserve the intrinsic properties of GO. We demonstrated that both chlorine atoms were substituted by GSH in the presence of glutathione transferase (GST), inducing a relevant bathochromic shift in the absorption/emission features and thus generating the active PS. Ex vitro assessment using cell lysates containing cytoplasmatic GST revealed the intracellular catalytic mechanism for the nucleophilic substitution of the GO-BODIPY adduct with GSH. Confocal microscopy studies showed important differences in the cellular uptake of free BODIPY and GO-BODIPY and revealed the coexistence of GO-BODIPY, GO-BODIPY-GS, and GO-BODIPY-GS2 species inside vesicles and in the cytoplasm of the cells after 24 h of incubation. In vitro biocompatibility and safety of GO and GO-BODIPY were evaluated in 2D and 3D models of prostate adenocarcinoma cells (PC-3), where no toxicity was observed up to 100 µg/mL of GO/GO-BODIPY in all treated groups 24 h post-treatment (cell viability > 90%). Only a slight decrease to 80% at 100 µg/mL was observed after 48 h of incubation. We demonstrated the efficacy of a GO adduct containing an α-chlorine-substituted BODIPY for the simultaneous depletion of intracellular GSH and the photogeneration of reactive oxygen species using a halogen white light source (5.4 mW/cm2) with a maximum in the range of 500-800 nm, which significantly reduced cell viability (< 50%) after irradiation. Our study provides a new vision on how to apply BODIPY derivates and potentiate the toxicity of PDT in prostate and other types of cancer.

Chemical etching of silicon assisted by graphene oxide

2019 ◽  
Vol 58 (5) ◽  
pp. 050924 ◽  
Author(s):  
Wataru Kubota ◽  
Ryuko Ishizuka ◽  
Toru Utsunomiya ◽  
Takashi Ichii ◽  
Hiroyuki Sugimura
Keyword(s):  
Graphene Oxide ◽  
Chemical Etching

Electroless chemical etching of silicon in aqueous NH4F/AgNO3/HNO3 solution

2013 ◽  
Vol 284 ◽  
pp. 894-899 ◽  
Author(s):  
Nacéra Megouda ◽  
Toufik Hadjersi ◽  
Sabine Szunerits ◽  
Rabah Boukherroub
Keyword(s):  
Chemical Etching ◽  
Hno3 Solution

A gas-liquid sensor functionalized with graphene-oxide on chalcogenide tapered fiber by chemical etching

2021 ◽  
pp. 1-1
Author(s):  
Qianyu Qi ◽  
Luoyao Chu ◽  
Weijie Zhou ◽  
Peiqing Zhang ◽  
Xunsi Wang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Chemical Etching ◽  
Tapered Fiber

Monitoring Hydrogen Peroxide Using Electrochemically Reduced Graphene Oxide Modified Screen Printed Electrodes During Metal Assisted Chemical Etching Processes

2021 ◽  
Author(s):  
Chun-Wen Lan ◽  
Subbiramaniyan Kubendhiran ◽  
Gavin Sison ◽  
Hsiao Ping Hsu
Keyword(s):  
Hydrogen Peroxide ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Electrochemical Method ◽  
Chemical Etching ◽  
Etching Process ◽  
Etching Solution ◽  
Reduced Graphene ◽  
Metal Assisted Chemical Etching ◽  
Screen Printed

Abstract The concentrations of etchant solution substituents in metal assisted chemical etching (MACE) processes control the morphology and reflectivity of subsequently etched wafers. In particular, the concentration of hydrogen peroxide (H2O2) plays a vital role in the MACE process. Unfortunately, the H2O2 concentration is not stable when prolonging the etching process at higher temperatures. As a result, the commercialization of MACE processes for the production of IP texturization has appeared industrially unattractive. Herein, we proposed an innovative method to monitor hydrogen peroxide during the MACE process with an electrochemical method. Reduced graphene oxide (RGO) prepared through an environmentally benign electrochemical method was used to modify a screen-printed electrode (SPE). Under an optimized condition, the RGO/SPE was used to test etching solutions. The MACE process was conducted and the hydrogen peroxide concentration within the etching solution was checked by the RGO/SPE. The RGO/SPE demonstrated excellent electrochemical performance and could record changes to H2O2 concentrations with cyclic voltammetry (CV). Interestingly, the presence of copper (Cu) in the etching solution catalyzed not only the etching process, but also the electrochemical reduction of H2O2. After etching, the reflectivity and structural morphology of the etched wafers were checked. The described modified electrode is disposable, and the fabrication process is rapid and inexpensive, allowing for real time application in, and control of, MACE processes.

Graphene oxide–palladium modified Ag–AgBr: a visible-light-responsive photocatalyst for the Suzuki coupling reaction

RSC Advances ◽  
2014 ◽  
Vol 4 (74) ◽  
pp. 39242-39247 ◽  
Author(s):  
Shutao Gao ◽  
Ningzhao Shang ◽  
Cheng Feng ◽  
Chun Wang ◽  
Zhi Wang
Keyword(s):  
Graphene Oxide ◽  
Visible Light ◽  
Catalytic Mechanism ◽  
Coupling Reaction ◽  
Suzuki Coupling ◽  
Suzuki Coupling Reaction

In this paper, a plasmonic Ag–AgBr photocatalyst functionalized with graphene oxide–Pd was successfully fabricated and used as an efficient visible-light-responsive photocatalyst for the Suzuki coupling reaction. A possible catalytic mechanism for the photocatalyst is proposed.

Cobalt Hydroxide/Oxide Hexagonal Ring–Graphene Hybrids through Chemical Etching of Metal Hydroxide Platelets by Graphene Oxide: Energy Storage Applications

ACS Nano ◽  
2014 ◽  
Vol 8 (3) ◽  
pp. 2755-2765 ◽  
Author(s):  
C. Nethravathi ◽  
Catherine R. Rajamathi ◽  
Michael Rajamathi ◽  
Xi Wang ◽  
Ujjal K. Gautam ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Energy Storage ◽  
Chemical Etching ◽  
Metal Hydroxide ◽  
Cobalt Hydroxide ◽  
Hexagonal Ring ◽  
Energy Storage Applications
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