scholarly journals Corrosion Behaviour and J774A.1 Macrophage Response to Hyaluronic Acid Functionalization of Electrochemically Reduced Graphene Oxide on Biomedical Grade CoCr

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1078
Author(s):  
Belén Chico ◽  
Blanca Teresa Pérez-Maceda ◽  
Sara San José ◽  
María Lorenza Escudero ◽  
María Cristina García-Alonso ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Hyaluronic Acid ◽  
Reduced Graphene Oxide ◽  
Inflammatory Responses ◽  
Electrochemical Impedance ◽  
Reduced Graphene ◽  
Electrochemically Reduced Graphene Oxide ◽  
Metal Metal ◽  
Anti Inflammatory ◽  
Joint Prostheses

Improvements in the lubrication of metal–metal joint prostheses are of great clinical interest in order to minimize the particles released during wear–corrosion processes. In this work, electrochemically reduced graphene oxide (ErGO) on CoCr was functionalized with hyaluronic acid (ErGOHA). Functionalization was carried out by soaking for 24 h in phosphate buffer saline (PBS) solution containing 3 g/L hyaluronic acid (HA). The corrosion performance of CoCrErGO and CoCrErGOHA surfaces was studied by electrochemical impedance spectroscopy (EIS) for 7 days in PBS. Biocompatibility and cytotoxicity were studied in mouse macrophages J774A.1 cell line by the measurement of mitochondrial activity (WST-1 assay) and plasma membrane damage (LDH assay). The inflammatory response was examined through TNF-α and IL-10 cytokines in macrophages culture supernatants, used as indicators of pro-inflammatory and anti-inflammatory responses, respectively. EIS diagrams of CoCrErGOHA revealed two time constants: the first one, attributed to the hydration and diffusion processes of the HA layer adsorbed on ErGO, and the second one, the corrosion resistance of ErGOHA/CoCr interface. Macrophage assays showed better behavior on CoCrErGOHA than CoCr and CoCrErGO surfaces based on their biocompatible, cytotoxic, and inflammatory responses. Comparative analysis of IL-10 showed that functionalization with HA induces higher values of anti-inflammatory cytokine, suggesting an improvement in inflammatory behavior.

scholarly journals Enhancement of the Electrochemical Properties of an Open-Pore Graphite Foam with Electrochemically Reduced Graphene Oxide and Alternating Current Dispersed Platinum Particles

Coatings ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 551 ◽  
Author(s):  
Javier Fernández ◽  
José Bonastre ◽  
José Miguel Molina ◽  
Francisco Cases
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Electrochemical Impedance ◽  
3D Structure ◽  
Alternating Current ◽  
Synthesis Time ◽  
Reduced Graphene ◽  
Electrochemically Reduced Graphene Oxide ◽  
Platinum Particles ◽  
Graphite Foam

This paper aimed to improve the electrochemical activity of a pitch-derived open-pore graphite foam (GF) by an electrochemical coating of reduced graphene oxide (RGO) and platinum particles without significantly affecting its 3D-structure. RGO was synthesized using cyclic voltammetry (CV) from a 3 g L−1 GO and 0.1 M LiClO4 solution. For the electrodeposition of Pt particles, an alternating current method based on electrochemical impedance spectroscopy (EIS) was used. A sinusoidal voltage from a fixed potential Ei was varied following a selected amplitude (ΔEac = ± 0.35 V) in a frequency range of 8 Hz ≤ fi ≤ 10Hz, where i = 500. This method proved its efficiency when compared to the traditional CV by obtaining more highly electroactive coatings in less synthesis time. For samples’ characterization, physical measures included permeability, pressure drop, and nitrogen adsorption isotherms. The electrochemical characterization was performed by CV. The surface morphology and chemical composition were examined using field emission electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDX), respectively. RGO improved the electron transfer rate constant of GF, and a more homogeneous coating distribution of reduced size Pt particles was obtained.

scholarly journals Simultaneous Determination of Uric Acid and Xanthine Using a Poly(Methylene Blue) and Electrochemically Reduced Graphene Oxide Composite Film Modified Electrode

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Gen Liu ◽  
Wei Ma ◽  
Yan Luo ◽  
Deng-ming Sun ◽  
Shuang Shao
Keyword(s):  
Methylene Blue ◽  
Uric Acid ◽  
Graphene Oxide ◽  
Composite Film ◽  
Simultaneous Determination ◽  
Reduced Graphene Oxide ◽  
Modified Electrode ◽  
Reduced Graphene ◽  
Electrochemically Reduced Graphene Oxide

Poly(methylene blue) and electrochemically reduced graphene oxide composite film modified electrode (PMB-ERGO/GCE) was successfully fabricated by electropolymerization and was used for simultaneous determination of uric acid (UA) and xanthine (Xa). Based on the excellent electrocatalytic activity of PMB-ERGO/GCE, the electrochemical behaviors of UA and Xa were studied by cyclic voltammetry (CV) and square wave voltammetry (SWV). Two anodic sensitive peaks at 0.630 V (versus Ag/AgCl) for UA and 1.006 V (versus Ag/AgCl) for Xa were given by CV in pH 3.0 phosphate buffer. The calibration curves for UA and Xa were obtained in the range of 8.00 × 10−8~4.00 × 10−4 M and 1.00 × 10−7~4.00 × 10−4 M, respectively, by SWV. The detection limits for UA and Xa were3.00×10-8 M and5.00×10-8 M, respectively. Finally, the proposed method was applied to simultaneously determine UA and Xa in human urine with good selectivity and high sensitivity.

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.

Sign in / Sign up

Export Citation Format

Share Document