Graphene Oxide Coatings Research Articles

Protein spot arrays on graphene oxide coatings for efficient single-cell capture

Biomedical applications such as cell screening or cell–cell interaction studies require placement and adhesion of cells on surfaces with controlled numbers and location. In particular, single-cell arraying and positioning has come into focus as a basis of such applications. An ideal substrate would combine biocompatibility with favorable attributes such as pattern stability and easy processing. Here, we present a simple yet effective approach to single-cell arraying based on a graphene oxide (GO) surface carrying protein (fibronectin) microarrays to define cell adhesion points. These capture NIH-3T3 cells, resulting in cell arrays, which are benchmarked against analogous arrays on silanized glass samples. We reveal significant improvement in cell-capture performance by the GO coating with regards to overall cell adhesion and single-cell feature occupancy. This overall improvement of cell-arraying combined with retained transparency of substrate for microscopy and good biocompatibility makes this graphene-based approach attractive for single-cell experiments.

Targeting and promoting atherosclerosis regression using hybrid membrane coated nanomaterials via alleviated inflammation and enhanced autophagy

Atherosclerosis is the leading cause of death and disability worldwide, which is lack of efficient strategy for targeted therapy. In this work, we reported a hybrid membrane coated graphene oxide quantum dots (GOQDs) nanomaterial loading atorvastatin (AT) to achieve targeted atherosclerosis therapy. In this biomimetic nanomaterial, macrophages membrane (Møm) was used to extend the half-life of AT and enhance the accumulation of AT in the atherosclerotic plaques. Meanwhile, red blood cell membrane (RBCm) was adopted to reduce the amount of Møm usage. Furthermore, hyaluronic acid (HA) was inserted into the hybrid membrane to enhance the internalization of nanomaterial into activated macrophages of atherosclerotic plaques. In vitro assay demonstrated that this nanomaterial can release AT in an acidic pH-responsive manner. In vivo assay demonstrated that both long-term low-dose and short-term high-dose regimens with favorable safety can effectively inhibit the development of the early atherosclerosis and markedly regress the progression of advanced atherosclerotic plaques, respectively. Molecular mechanism exploration indicated that the anti-atherosclerosis effect of the nanomaterial was mediated by alleviating inflammation to reduce lipid influx and enhancing autophagy to promote cholesterol efflux. Overall, this biomimetic nanomaterial provides an alternative for developing safe and efficient strategy for atherosclerosis therapy.

Structural damage in graphene oxide coatings onto Nb substrates upon laser irradiation

In this work graphene oxide (GO) coatings were obtained on Nb substrates by electrophoretic deposition (EPD), using a ramp of stepped potential and variable deposition time, to evaluate the feasibility as a protective coating against the exposition to a 20 W Yb laser (1070 nm). Laser irradiation constitutes a first approximation to the potential damage by local high heat loads that could occur in a Tokamak-type fusion reactor. GO coatings can act as the first barrier against exposure to the fusion reactor plasma, but the coating may experience local high heat loads and simultaneous exposure to energetic particles. The GO/Nb coatings were irradiated with different laser power-frequency settings. With X-ray photoelectron spectroscopy, the bonding evolution of the coatings was followed for each deposition time. Scanning electron microscopy was used to evaluate the coating morphology before and after laser irradiation, whereas Raman spectroscopy was used to evaluate the structural evolution of GO coatings, crystallinity , and disorder in the graphene oxide. An increase of the crystallite size due to sp 2 restoration was observed for the films prepared up to 10 s/V. Atomic force microscopy was used to study the film morphology and to estimate the film thickness by comparing the z-offset between the substrate and coating topography images. Film thickness reduces from ca. 280 nm to 100 nm with the increase in the time at each voltage step. Coating tolerance against laser-induced damage was observed up to 34% of the full laser power, where the coating was damaged and local metal melting was observed. The coating damage occurs between 4.9 × 10 8 MW/m 2 and 2.5 × 10 9 MW/m 2 and higher power levels triggered the occurrence of melting in the metallic substrate. The reduction in laser damage is attributed to the enhanced thermal dissipation by the sp 2 dominion as the crystallite size increases. GO coatings prepared by electrophoresis are shown to be promising to protect nuclear components against damage for high heat loads. • Adherent and stable GO coatings were obtained on Nb substrates by novel EPD process. • GO coatings were irradiated with high-power laser for structural damage evaluation. • Damage threshold for GO coating is 4.9 × 10 8 MW/m 2 and for Nb substrate 2.5 × 10 9 MW/m 2 . • Reduction of GO and sp 2 domain restoration after EPD enhance resistance to radiation. • GO coatings are feasible as plasma facing components in nuclear fusion reactors.

Graphene oxide nanocoating for enhanced corrosion resistance, wear resistance and antibacterial activity of nickel‑titanium shape memory alloy

For nickel‑titanium (NiTi) shape memory alloy used in clinical orthodontic treatment, the corrosion media and bacteria in saliva increase its corrosion tendency; and the high surface frictional resistance limits the efficiency of teeth movement. Corrosion resistance, friction performance, and antibacterial properties of graphene oxide (GO) coatings on NiTi alloy were investigated as a function of the GO concentration. Compared with the NiTi substrate, GO coatings with different concentrations reduced the corrosion tendency in the artificial saliva, and enhanced the lubricity as well as anti-Streptococcus mutans ability. However, when the GO concentration was low, the corrosion resistance and friction resistance of the coating were insufficient; when the concentration was too high, cells cultured with the GO-coated NiTi were more susceptible to oxidative stress damage. This study provided a comprehensive assessment of nanometer-level GO coatings on NiTi alloys used in orthodontics, with the purpose of informing and guiding further detailed research to optimize the surface properties of GO-coated dental alloys.

Metal-oxide coated Graphene oxide nano-composite for the treatment of pharmaceutical compound in photocatalytic reactor: Batch, Kinetics and Mathematical Modeling using Response Surface Methodology and Artificial Neural Network.

Titanium dioxide (TiO2) photocatalyst has gained constant interest in the treatment of wastewater because of its greater stability, lower cost, low-toxicity, high efficiency, and more reactivity under UV radiation. On the other hand, Graphene oxide (GO) possesses high electron mobility, and therefore when GO is combined with TiO2, the photocatalytic activity of TiO2 is increased. In this study, nano-composite was synthesized in a hydrothermal reactor using two types of TiO2 nanoparticles (TiO2 consisting of a mixture of rutile and anatase phase (Type 1) and bioreduced TiO2 (Type 2)) and the efficiency of both the TiO2-GO nanocomposite to remove the drug Carbamazepine (CBZ) was investigated. The TiO2-GO nanocomposite with the Type 1 TiO2 exhibited greater efficiency hence further studies were conducted with that composite. The efficiency of TiO2-GO nanocomposite for the purpose of removing CBZ were investigated in presence of different types of incident radiation like Solar radiation, white light and three type of Ultraviolet radiation (A, B, C). The removal of the drug by TiO2-GO composite has been optimized using response surface methodology and artificial neural network. From this study, the maximum reduction was observed was 91.2% and whereas in case of the RSM optimization study the maximum removal that was observed was 91.7%. The validation of the RSM model was done using the mathematical analysis of the model equation of RSM. Different kinetics models was also analyzed using the experimental data and it was observed that it followed pseudo-second-order kinetics. The optimization using ANN also showed a close interaction with the experimental results.

Ag Nanoparticle-Decorated Graphene Oxide Coatings on the Inner Walls of Optofluidic Capillaries for Real-Time Trace SERS Detection

Ag Nanoparticle-Decorated Graphene Oxide Coatings on the Inner Walls of Optofluidic Capillaries for Real-Time Trace SERS Detection

Bio-enhanced polyrhodanine/graphene Oxide/Fe3O4 nanocomposite with kombucha solvent supernatant as ultra-sensitive biosensor for detection of doxorubicin hydrochloride in biological fluids

Cardiotoxicity and other side effects of current antineoplastic agents with narrow therapeutic windows, such as doxorubicin hydrochloride (DOX), have increased the need for advanced real-time monitoring approaches to control their dosage and minimize common side effects. In this study, we reinforced the biocompatible and electrosensitive polymeric structure of polyrhodanine with iron(II,III) oxide (Fe3O4) and coated graphene oxide (GO) with Fe3O4 (GO-Fe3O4) nanoparticles. The resulting hybrid polymeric platform was bio-enhanced by extraction of kombucha solvent supernatant and used as a highly sensitive biosensor with enhanced electroactive CN+ functional groups for real-time detection of DOX in the human blood plasma sample. The developed platform was well characterized by performing different analyses, and its applicability was evaluated using an electrochemical approach. The results showed the superior sensitivity (167.62 μA μM−1 cm−2), low detection limit (DL, 0.008 μM), and quantification limit (QL, 0.056 μM) of the proposed biosensor. The biosensor detected DOX in the biological fluid with optimal accuracy (>99%), highlighting the ideal performance of the fabricated polymeric biosensor.

Corrosion resistance and biocompatibility of graphene oxide coating on the surface of the additively manufactured NiTi alloy

In recent years, selective laser melting (SLM)-NiTi alloy has attracted widespread interest due to its ability to prepare medical implant materials with complex shapes and high dimensional accuracy. However, SLM-NiTi biomedical materials still face the problems of Ni ion release, poor corrosion performance, and biological inertness. This study is the first to report that the preparation of graphene oxide (GO) coatings on the SLM-NiTi alloy via the electrodeposition method. By changing the deposition time, the effect on coating morphology, corrosion resistance, biomineralization, and biocompatibility was studied. The result showed that GO coating could effectively enhance the corrosion resistance of SLM-NiTi alloy and inhibit the Ni ions release. The GO coating obtained when the deposition time was 20 min possessed the best corrosion resistance, which corrosion current density was about two orders of magnitude lower than that of SLM-NiTi alloy. Moreover, GO coating can effectively promote the adhesion, growth, and proliferation of osteoblasts. Therefore, the GO coated SLM-NiTi alloy is promising for clinical application.

Investigation of anticorrosion properties of epoxy GO nanocomposites spin coated Aluminum Alloy 7075

The bisphenol A diglycidyl ether-polyaminoamide (epoxy resin)–graphene oxide (GO) nanocomposites have been prepared by chemical methods. The aim of this study is to produce epoxy –GO coatings on Aluminum Alloy 7075 and study the anticorrosion properties. Thin films have been characterized by scanning electron microscope – Energy Dispersive X-rays Spectroscopy (EDX) and Raman spectra. Raman spectra show the successful bonding of GO functional groups with epoxy. The composition of epoxy and GO is characterized by EDX. The Tafel plots were undertaken for analysis of corrosion of coating material. Therefore, the reduction of corrosion current of epoxy–GO nanocomposites coated Al alloy 7075 show its superior corrosion resistance properties. This is further confirmed by electrochemical impedance spectroscopy and potentiodynamic polarization. The very high value of low frequency impedance modulus (i.e. 1010 Ω cm2) shows surprising anticorrosive effect on coating. The epoxy–GO spin coating in Al Alloy 7075 is significantly reduces the corrosion current density ( Icorr) and corrosion rate due to anticorrosion properties of GO.

Improvement in Long-Term Stability of Field Effect Transistor Biosensor in Aqueous Environments Using a Combination of Silane and Reduced Graphene Oxide Coating

Improvement in Long-Term Stability of Field Effect Transistor Biosensor in Aqueous Environments Using a Combination of Silane and Reduced Graphene Oxide Coating

Preparation of Graphene Oxide Coatings on Textured Ti6al4v by Laser Micromachining and Electrophoretic Deposition for Improved Biocompatibility

Preparation of Graphene Oxide Coatings on Textured Ti6al4v by Laser Micromachining and Electrophoretic Deposition for Improved Biocompatibility

Suppression of Secondary Electron Emission on Oxygen-Free Copper Surface of Reduced Graphene Oxide Coatings Prepared by Electrophoretic Deposition

Suppression of Secondary Electron Emission on Oxygen-Free Copper Surface of Reduced Graphene Oxide Coatings Prepared by Electrophoretic Deposition

Enhanced Boiling Heat Transfer by Nucleation Patterning with Self-Assembly of Reduced Graphene Oxide Coating

Enhanced Boiling Heat Transfer by Nucleation Patterning with Self-Assembly of Reduced Graphene Oxide Coating

Vitamin C-Reduced Graphene Oxide Coatings Improve the Performance and Stability of Multimodal Microelectrodes for Neural Recording, Stimulation, and Dopamine Sensing

Vitamin C-Reduced Graphene Oxide Coatings Improve the Performance and Stability of Multimodal Microelectrodes for Neural Recording, Stimulation, and Dopamine Sensing

Facile fabrication of graphene oxide and MOF-based superhydrophobic dual-layer coatings for enhanced corrosion protection on magnesium alloy

Corrosion is an inevitable and thorny problem when magnesium (Mg) alloys are used in marine environments. Superhydrophobic coatings have great potential for metal corrosion protection due to their superhydrophobicity and self-cleaning properties. However, the poor mechanical stability of the surface seriously hinders the practical application. Herein, a robust superhydrophobic graphene oxide (GO)/polypyrrole (PPy)-zeolitic imidazolate framework-8 (ZIF-8) dual-layer coating was prepared on the surface of magnesium (Mg) alloy by electrodeposition and spraying method, which was composed of a bottom GO layer and a upper superhydrophobic PPy/ZIF-8 layer. The GO layer extends the transmission path of corrosion ions and the superhydrophobic coating prevents the contact between the Mg alloy and the corrosive solution. In addition, the dual-layer superhydrophobic coating has excellent self-cleaning and mechanical properties. More importantly, the as-prepared coating can withstand 3.5 wt% NaCl solutions for 120 h and still maintain good corrosion resistance. Furthermore, the GO layer and the superhydrophobic layer have a synergistic effect, which significantly improves the corrosion resistance of Mg alloys. The facile method and superhydrophobic dual-layer coatings will have good application prospects on a variety of metal substrates.

Barium alginate as a skeleton coating graphene oxide and bentonite-derived composites: Excellent adsorbent based on predictive design for the enhanced adsorption of methylene blue

The phenomenon that calcium alginate does not exhibit high adsorption capacity as a carrier material has not been reasonably explained or solved. In this paper, a new viewpoint that the orbital energy level of metal ions and the binding degree of the α-l-guluronate and β-d-mannuronate units affect the adsorption performance of the composite was innovatively proposed. Taking barium alginate (BA) as an example, the possibility of replacing calcium alginate is discussed. Barium alginate/graphene oxide (BA/GO) membranes and three-dimensional (3D) barium alginate-bentonite-graphene oxide derived (3D-BA) hydrogels were prepared by vacuum freeze-drying to remove methylene blue. The structure and morphology of the prepared adsorbents were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, thermogravimetry and Fourier transform infrared spectroscopy. The effects of adsorbent dosage, doping ratio, temperature, contact time, pH value and initial dye concentration on the adsorption performance of BA composites were investigated. The adsorption capacities of the BA/GO and 3D-BA materials were 1011.3 and 710.3 mg/g, respectively. The BA/GO membrane exhibited stable filtration performance against high concentrations of dyes. Benefiting from the strong interaction between bentonite, sodium alginate and Ba2+, the 3D-BA hydrogel showed higher thermal stability and better adsorption efficiency than other materials. The Elovich kinetic model and Sips equation can appropriately describe the adsorption process. The results show that barium alginate is a better carrier material than calcium alginate.

Tribological properties of the hierarchically structured graphene oxide composite coatings reinforced with polyvinyl alcohol

Inspired by natural nacre, hierarchically structured graphene oxide (GO) composite coatings reinforced with different concentrations of polyvinyl alcohol (PVA) were fabricated for development of novel protective surface coatings. It was found that the tribological performance of the GO coating deposited on 304 stainless steel could be significantly improved by including PVA in the coating. The GO/PVA composite coating showed a low friction coefficient of 0.085 and a significant reduction in wear rate compared to that of the GO coating. It was determined that incorporation of PVA between the GO layers enhanced the durability of the coatings. These results showed that PVA can be effectively used as a reinforcing agent of hierarchically structured GO coatings for low friction and wear applications.

Fabrication of Superhydrophobic Nickel‐Reduced Graphene Oxide Coating with Corrosion Resistance in High‐Temperature and High‐Pressure CO2 Environment

A novel superhydrophobic nickel‐reduced graphene oxide (sNi‐rGO) coating is fabricated successfully on an N80 steel substrate using a simple electrodeposition method combined with a directly elevated current approach. The results show that the water contact angle (WCA) of the coating is 162.87° when the concentration of graphene oxide (GO) is 0.6 g L−1. The autoclave experiments indicate that the coatings still maintain superhydrophobic and corrosion resistance under high‐temperature and high‐pressure CO2 condition. The density functional theory calculations are employed to investigate the adsorption models of carbonate (CO32−) on the surfaces of iron (Fe), nickel (Ni), and rGO to further verify the CO2 corrosion resistance mechanism of the sNi‐rGO coating.

Ternary Composite of Molybdenum Disulfide-Graphene Oxide-Polyaniline for Supercapacitor

The ever-increasing need for small and lightweight power sources for use in portable or wearable electronic devices has spurred the development of supercapacitors as a promising energy storage and conversion system. In this work, a simple, facile and easy-to-practice method has been developed to employ carbon paper (CP) as the support to coat molybdenum disulfide (MoS2) and graphene oxide (GO), followed by electrodeposition of polyaniline (PANI) to render CP/MoS2-GO-PANI. The preparation parameters, such as amounts of MoS2, GO and number of aniline electropolymerization cycles, have been optimized to render CP/MoS2-GO-PANI the best capacitive performance. The as-prepared optimal CP/MoS2-GO-PANI is characterized by X-ray powder diffraction, scanning electron microscopy, energy-dispersive spectroscopy, and X-ray photoelectron spectroscopy. The supercapacitive properties of CP/MoS2-GO-PANI as an electrode have been evaluated electrochemically via cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy testing. CP/MoS2-GO-PANI delivers a specific capacitance of 255.1 F g−1 at 1.0 A g−1 and exhibits excellent rate capability under larger current densities. Moreover, a symmetrical supercapacitor is assembled and three are connected in series to power a light-emitting diode for ∼15 min, demonstrating the promising application potential of CP/MoS2-GO-PANI-based supercapacitor.

Testing new graphene oxide‐coated glazing for papyrus manuscripts in museums: Part I

The display of papyrus and paper (as cellulosic materials) in the Egyptian museums is always critical due to the traditional placement of display of sensitive materials between two plates of glass, acrylic, or other types of glazing materials. The sensitivity of the glazing materials to abrasion, ultraviolet rays, dust adhesion, and high light reflectivity are considered concerning issues to conservators, curators, and visitors. In this paper, thin protective coatings of graphene oxide (GO) were synthesized by modified Hummers' method and deposited on selected museums' glazing materials (glass and acrylic) using spin coating. Multi‐analytical techniques were employed to assess the applicability of GO‐coated glazing including scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), Raman spectroscopy (RS), Fourier transform infrared spectroscopy (FTIR), microhardness testing, NIR VIS, and UV spectrophotometer and static potential measurements. The results showed that the glass glazing hardness was increased by ~10% due to the deposition of the GO coating. Moreover, according to glazing type, the reflectance values of the GO‐coated glazing samples, compared with the uncoated samples, confirmed that the thin film of GO improved the UV rays blocking. As is evident in the GO‐coated glass where approximately 27% of UV rays have been blocked, likewise, 19% of UV rays were blocked in GO‐coated acrylic (TRU VUE). Considering VIS and NIR reflection spectra of GO‐coated plexiglass, a higher reflectance is presented by 29%. Furthermore, the static potential measurements showed an energy decline in GO‐coated glazing compared with the uncoated samples.