Compatibility Of Graphene Oxide Research Articles

PH-Responsive Graphene Oxide-Based 2D/3D Composite for Enhancing Anti-Corrosion Properties of Epoxy Coating.

The functionalized graphene oxide (GO)-based composites as fillers added into organic coatings are desired for realizing the longstanding corrosion protection of carbon steel. Here, the pH-responsive two-dimensional/three-dimensional (2D/3D) GO-based composite (ZIF-90-AAP/GO) was developed by environmentally friendly corrosion inhibitor 4-aminoantipyrine (AAP) anchored on the in situ growth of zeolite imidazolate framework-90 (ZIF-90) on the GO surface (ZIF-90/GO) through the Schiff base reaction. The active filler (ZIF-90-AAP/GO) was incorporated into an epoxy coating (EP) to obtain a high-performance self-healing coating on the surface of carbon steel. ZIF-90-AAP can greatly improve dispersion and compatibility of GO in EP. The low-frequency impedance modulus of ZIF-90-AAP/GO-EP can still reach up to 1.35 × 1010 Ω⋅cm2 after 40 days, which is about three orders of magnitude higher than that of the EP containing GO (GO-EP) relying on its passive and active corrosion protection. Meanwhile, ZIF-90-AAP/GO-EP exhibits excellent self-healing performance. The self-healing rate of ZIF-90-AAP/GO changes from negative to positive after 24 h, which results from the effective corrosion inhibition activity of ZIF-90-AAP for carbon steel based on the pH-triggered controlled release of AAP. The developed pH-responsive 2D/3D GO-based composite coating is very attractive for the corrosion protection of carbon steel.

A long-term anti-corrosion and cathodic delamination resistant epoxy coating based on COF grafted GO nanofillers

Here, a long-term anti-corrosive epoxy (EP) coating based on nano-hybrid filler was developed. The surface of graphene oxide (GO) was aminated with (3-aminopropyl) triethoxysilane (APTES), and then the porous covalent organic framework (COF) was in-situ grown on amino functionalized graphene oxide (FGO) nanosheets by Schiff-based reaction to prepare FGO-COF nanofillers. Different characterization methods proved the successful modification of GO nanosheets with COF particles. The excellent water resistance of composite coatings was characterized through contact angle, adhesion, and water uptake tests. Transmission electron microscope (TEM) and molecular dynamics (MD) methods showed that the grafting of COF enhanced the dispersion and compatibility of GO in the coating. EIS measurements, salt spray analysis and cathodic delamination test indicated the significant improvements in the protective properties of the composite coatings compared with pure EP coating. The low-frequency impedance modulus of 1% FGO-COF composite coating reached higher than 6.8 × 109 Ω·cm2 after immersed in sea water for 60 days. In addition, the 1% FGO-COF composite coating performed only 34% delamination ratio after 120 h cathodic delamination test.

Printable Graphene Oxide Nanocomposites as Versatile Platforms for Immobilization of Functional Biomolecules

AbstractA series of novel nanocomposites containing graphene oxide (GO) suitable for stereolithography is presented. Different loads of GO are tested, identifying that these materials can be printed with concentrations up to 2.5 wt% GO, presenting improved mechanical properties for concentrations below 1.0 wt% GO. In this range, the nanocomposites exhibit higher strength and toughness when compared to the pristine resin. Microscopic analyses of the material demonstrate that this can be correlated with the good compatibility of GO with the resin, which favors its homogeneous dispersion in the form of flexible nanoplates. After manufacturing, the availability of GO to participate in surface modification reactions with chitosan (CHI) and an alkaline phosphatase (ALP) is evaluated. CHI and ALP are well‐known to act as biological cues in biorecognition processes, evidencing that these nanocomposites are suitable as platforms for selective immobilization of functional biomolecules.

Investigation of the anticorrosion properties of graphene oxide-modified waterborne epoxy coatings for AA6061

In this study, the two-dimensional material graphene oxide (GO) was modified by a quaternary ammonium salt (Dimethyloctadecyl[3-(trimethoxysilyl) propyl] ammonium chloride (TPOAC)) and then introduced into the waterborne epoxy (WEP) coatings to improve the corrosion resistance of the WEP coatings on the aluminum alloy substrate. TPOAC as a modifier not only improves the compatibility of GO with the polymer coatings, but also greatly reduces the internal defects of the WEP coatings. Scanning electronic microscopy (SEM) images show that the composite WEP coatings are denser and internal defects are greatly reduced. Electrochemical test (electrochemical impedance spectroscopy (EIS)) was used to evaluate the corrosion resistance of the WEP coatings. Consequently, after being immersed in 3.5 wt% NaCl solution for 30 days, modulus at lowest frequency (2.7 × 107 Ω cm2) of the composite WEP coating reveals two orders of magnitude higher than that of blank WEP coating (5.6 × 105 Ω cm2). The results show that the modified GO enhances the penetration resistance of WEP coatings to corrosive media and improves the long-term anticorrosion protection performance of WEP coatings on aluminum alloy substrate.

Effect of covalent organic framework modified graphene oxide on anticorrosion and self-healing properties of epoxy resin coatings

Graphene oxide (GO) can enhance the corrosion resistance of epoxy coating, but there are problems such as poor filler dispersion and mechanical damage that will reduce the coating corrosion resistance. To resolve these problems, here, we used a facile and green liquid-phase synthetic strategy to grow covalent organic framework (COF) on GO sheets with 1,3,5-Triformylphloroglucinol and p-phenylenediamine as monomers for the COF synthesis. The COF could not only improve the compatibility of GO with epoxy coating, but also act as a nanocontainer for loading corrosion inhibitors. Electrochemical impedance spectroscopy showed that the low-frequency impedance of GO/COF-2% coating immersed in 3.5 wt% NaCl solution for 60 days was 8.58 × 108 Ω cm2. This was one order of magnitude higher than that of GO-2%, showing excellent corrosion resistance. Then, corrosion inhibitor of benzotriazole (BTA) was loaded into GO/COF, where the adsorption and release of BTA was controlled by environmental pH values. Results proved that the GO/COF@BTA-2% reinforced epoxy coating had superior corrosion resistance as well as self-healing ability because of the good compatibility, greater crosslinking density and controllable release of BTA.

Dual-functional graphene oxide-based nanomaterial for enhancing the passive and active corrosion protection of epoxy coating

The poor dispersion and compatibility of graphene oxide (GO) in epoxy resins, and the lack of active corrosion protection of epoxy coating containing GO will greatly limit its applications in the field of corrosion protection. Here, we prepared dual-functional GO-based (GAS) nanomaterial, which can be evenly dispersed in epoxy coating and can create covalent bonds with epoxy resins through ring opening reaction (function one). The improvement in dispersion and compatibility enhances the impermeability of epoxy coating (passive corrosion protection). In addition, the prepared GAS nanomaterial can also be used to load corrosion inhibitor 2-mercaptobenzothiazole (MBT) and achieve pH-responsive release (function two), which can provide active corrosion protection for epoxy coating. Electrochemical impedance spectroscopy (EIS) results show that self-healing efficiency (ηself-healing) of the defected epoxy coating containing MBT-loaded GAS nanomaterial (GASM-Coat) changes from a negative value to a positive value after 24 h of immersion, which is attributed to the excellent self-healing properties of GASM-Coat. The combination of passive and active corrosion protection makes GASM-Coat achieve long-term corrosion protection of metal substrates.

Nanocomposite of Graphene Oxide Encapsulated in Polymethylmethacrylate (PMMA): Pre-Modification, Synthesis, and Latex Stability

The compatibility of graphene oxide with its dispersion medium (polymer) plays a critical role in the formation of nanocomposite materials with significant property improvements. Environmentally friendly miniemulsion polymerization, which allows a formation of nanoencapsulation in an aqueous phase and high molecular weight polymer/composite production is one promising method. In this study, we screened a series of amphiphilic modifiers and found that the quaternary ammonium (ar-vinyl benzyl) trimethyl ammonium chloride (VBTAC) pending carbon double bonds could effectively modify the graphene oxide (GO) to be compatible with the organophilic monomer. After that, free radical miniemulsion polymerization successfully synthesized stable latex of exfoliated poly (methyl methacrylate) (PMMA)/ GO nanocomposite. The final latex had an extended storage life and a relatively uniform particle size distribution. X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) analysis of this latex and its films indicated successful encapsulation of exfoliated nano-dimensional graphene oxide inside a polymer matrix.

Effect of Structure of Polymers Grafted from Graphene Oxide on the Compatibility of Particles with a Silicone-Based Environment and the Stimuli-Responsive Capabilities of Their Composites.

This study reports the utilization of controlled radical polymerization as a tool for controlling the stimuli-responsive capabilities of graphene oxide (GO) based hybrid systems. Various polymer brushes with controlled molecular weight and narrow molecular weight distribution were grafted from the GO surface by surface-initiated atom transfer radical polymerization (SI-ATRP). The modification of GO with poly(n-butyl methacrylate) (PBMA), poly(glycidyl methacrylate) (PGMA), poly(trimethylsilyloxyethyl methacrylate) (PHEMATMS) and poly(methyl methacrylate) (PMMA) was confirmed by thermogravimetric analysis (TGA) coupled with online Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Various grafting densities of GO-based materials were investigated, and conductivity was elucidated using a four-point probe method. Raman shift and XPS were used to confirm the reduction of surface properties of the GO particles during SI-ATRP. The contact angle measurements indicated the changes in the compatibility of GOs with silicone oil, depending on the structure of the grafted polymer chains. The compatibility of the GOs with poly(dimethylsiloxane) was also investigated using steady shear rheology. The tunability of the electrorheological, as well as the photo-actuation capability, was investigated. It was shown that in addition to the modification of conductivity, the dipole moment of the pendant groups of the grafted polymer chains also plays an important role in the electrorheological (ER) performance. The compatibility of the particles with the polymer matrix, and thus proper particles dispersibility, is the most important factor for the photo-actuation efficiency. The plasticizing effect of the GO-polymer hybrid filler also has a crucial impact on the matrix stiffness and thus the ability to reversibly respond to the external light stimulation.

Enhanced proton conductivity of sulfonated poly(ether ether ketone) membranes at elevated temperature by incorporating (3-aminopropyl)triethoxysilane-grafted graphene oxide

Making inexpensive proton exchange membrane with high proton conductivity for the proton exchange membrane fuel cell (PEMFC) is still a challenging problem. Graphene oxide (GO) nanoparticles grafted with (3-amino-propyl) triethoxy silane (APTES) were prepared and then incorporated into sulfonated poly(ether ether ketone) (SPEEK) matrix by solution casting to make the composite proton exchange membrane. The obtained nanoparticles and composite membranes were characterized by XRD, FT-IR, Raman, TGA, SEM, and UTM. GO treated with the silane coupling agent improved the dispersion stability and compatibility of GO in SPEEK, which decreased the agglomeration of GO nanoparticles in the SPEEK membrane. The prepared nanocomposite membranes exhibited better water retention properties and proton conductivity. The proton conductivity of the SPEEK membrane with 2 wt% amine functionalized GO (AGO) reached 11.32 mS/cm at 120 °C, which was 2.45-times higher than that of the pristine SPEEK membrane. The reason was that AGO nanoparticles disperse uniformly in the SPEEK membranes, which provides new channels for proton transfer. The potential application of this composite membrane in the PEMFC was indicated.

Graphene oxide enhanced aqueous epoxy composite coating derived from sustainable cardanol resource for corrosion protection

Conventional self-emulsified curing agent mainly focus on its stability, yet the contamination of raw materials are scarcely noted. Herein, a waterborne cardanol-based epoxy resin curing agent with emulsifying function was prepared by using the natural renewable biological material cardanol, and a waterborne biological epoxy resin coating was obtained by curing epoxy resin E51. The dual-functional product was synthesized by a two-process reaction (Mannich reaction and ring-opening reaction), as proved via FTIR and NMR techniques. In the curing process, the long alkyl chain in the curing agent molecule can shield the hydrophilic chain, thus improving the hydrophobicity and corrosion resistance of waterborne epoxy resin coating. With the help of this curing agent, graphene oxide (GO) is further used to improve the barrier effect of waterborne epoxy resin coating. The electrostatic interaction among curing agent, epoxy resin and GO improve the stacking dispersion and compatibility of GO in the coating. When the addition amount was 0.5 wt%, the thermal stability of the coating improved and the defects also reduced. The excellent corrosion resistance of the composite coating was verified by EIS. The results suggest that it is a potential candidate low-volatile organic compounds coatings for extending service life of metallic materials.

Development of Nateglinide Loaded Graphene Oxide-Chitosan Nanocomposites: Optimization by Box Behnken Design

Background:Nateglinide is an antidiabetic drug having biological half-life 1.5 h which shows a concise effect. Graphene oxide along with chitosan can be used as a nanocarrier for sustained release of Nateglinide.Objective:To develop Nateglinide loaded graphene oxide-chitosan nanocomposites and to evaluate for different characterization studies.Methods:Graphene Oxide (GO) was synthesized by improved hummer’s method and drug-loaded Graphene oxide - chitosan nanocomposites were prepared. Box Behnken design was used to carry out experiments. The nanocomposites were characterized for encapsulation efficiency and drug release. Morphology was studied using field emission scanning electron microscope and transmission electron microscope. An interaction between drug, polymer and GO was investigated by Fourier transform infrared spectroscopy and X-ray diffractometer along with in vitro drug release study.Results:The statistical evaluation of the design showed linear and quadratic models which are significant models for encapsulation efficiency (R1 0.6883, 0.9473) and drug loading (R2 0.6785, 0.9336), respectively. Fourier transform infrared spectroscopy showed the compatibility of GO, Chitosan and Nateglinide. X-ray diffractometer reveals the change in degree of crystallinity of drug. FE-SEM and TEM images confirmed the distribution of the drug within the nanocomposites. Design expert reveals that the concentration of GO has great influence on encapsulation efficiency. In Vitro drug release showed the sustained release of drug over the period of 12 h.Conclusion:GO-Chitosan nanocomposites can be used as a sustained release carrier system for Nateglinide to reduce dose frequency of drug as well as its probable side effects.

Effect of Compatibilizer on the Interface Bonding of Graphene Oxide/Polypropylene Composite Fibers.

To improve the interfacial bonding and thermal stability of graphene oxide (GO)/polypropylene (PP) composite fibers, a composite fiber with PP as the matrix, GO as reinforcement and maleic anhydride-grafted PP (PP-g-MAH) as a compatibilizer was prepared by a simple and efficient melt-blending method. The GO content was 0.0–5.0 wt %. According to the Fourier Transform Infrared (FT-IR) spectroscopy results, the interfacial bonding in the PP/MAH/GO composite fibers was improved. The Dynamic Mechanical Analysis (DMA) results show that the addition of GO resulted in better interfacial adhesion and higher storage modulus (E′). The loss modulus (E″) of the PP/MAH/GO-x composite fibers increased with increasing amount of added GO, whereas the loss factor (tan δ) decreased. GO and PP-g-MAH were analyzed by Thermogravimetric Analysis (TGA). The thermal stability of the composite fibers was improved compared to PP. Differential Scanning Calorimetry (DSC) analysis showed that the addition of PP-g-MAH to the composite fiber improved the interfacial bonding of GO in the PP matrix. Thus, compatibility between the two components was obtained. Based on the Scanning Electron Microscopy (SEM) results, the PP fibers exhibited relative orientation due to the strong crystalline morphology. The rough section, PP/GO blend fiber exhibits a very clear phase separation morphology due to the incompatibility between the two and the compatibility of GO and PP in PP/MAH/GO-3 composite fiber is improved, resulting in the interface between the two has improved.

Chitosan/graphene oxide mixed matrix membrane with enhanced water permeability for high-salinity water desalination by pervaporation

Pervaporation is a promising technology for water desalination. In this work, graphene oxide (GO) was incorporated into chitosan (CS) to fabricate mixed matrix membranes (MMMs) to explore the enhancement of water permeability for high-salinity water desalination and to understand the transport mechanism in the MMMs. The effect of GO content on the morphology, wettability and desalination performance of the membranes as well as the thermodynamic and kinetic behavior of water and salt permeation in the membranes were investigated. The MMMs have rougher and more hydrophilic surface, dense structure and improved mechanical stability owing to the good chemical compatibility of GO with CS matrix. The apparent activation energy results indicate the advantage of the MMMs in desalinating high-salinity water. The enhanced permeate flux of 30.0 kg/m2·h was obtained in desalinating 5 wt% aqueous NaCl solution at 81 °C with 1 wt% GO content and 99.99% of salt rejection was achieved. The solubility and diffusivity of H2O and NaCl in the MMMs demonstrate a trade-off effect on the water permeability and water/salt selectivity with increasing of GO content. The NaCl diffusion coefficient in the membranes was lower than that of H2O by two orders of magnitude, contributing to the high selectivity of the membrane.

Preparation and Characterization of Graphene Oxide-Modified Sapium sebiferum Oil-Based Polyurethane Composites with Improved Thermal and Mechanical Properties.

Bio-based polyurethane (PU) composites with superior thermal and mechanical properties have received wide attention. This is due to the recent rapid developments in the PU industry. In the work reported here, novel nano-composites with graphene oxide (GO)-modified Sapium sebiferum oil (SSO)-based PU has been synthesized via in situ polymerization. GO, prepared using the improved Hummers method from natural graphene (NG), and SSO-based polyol with a hydroxyl value of 211 mg KOH/g, prepared by lipase hydrolysis, were used as raw materials. The microstructures and properties of GO and the nano-composites were both characterized using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and tensile tests. The results showed that GO with its nano-sheet structure possessed a significant number of oxygen-containing functional groups at the surface. The nano-composites containing 1 wt % GO in the PU matrix (PU1) exhibited excellent comprehensive properties. Compared with those for pure PU, the glass transition temperature (Tg) and initial decomposition temperature (IDT) of the PU1 were enhanced by 14.1 and 31.8 °C, respectively. In addition, the tensile strength and Young’s modulus of the PU1 were also improved by 126% and 102%, respectively, compared to the pure PU. The significant improvement in both the thermal stability and mechanical properties for PU/GO composites was attributed to the homogeneous dispersion and good compatibility of GO with the PU matrix. The improvement in the properties upon the addition of GO may be attributable to the strong interfacial interaction between the reinforcing agent and the PU matrix.

Mechanical Properties and Wear Resistance of Sulfonated Graphene/Waterborne Polyurethane Composites Prepared by In Situ Method.

In order to improve the dispensability of graphene oxide (GO) in waterborne polyurethane (WPU), sulfonated graphene (SGO) with superior dispersity was prepared by modifying graphene oxide with sodium 2-chloroethane sulfonate to introduce hydrophilic sulfonic groups into the structure. SGO/WPU composites were prepared using isophorone diisocyanate (IPDI), polytetramethylene ether glycol (PTMEG 2000), dimethylolpropionic acid (DMPA) and SGO as raw materials. The influence of SGO content on composite properties were investigated. The structure and morphology of SGO and SGO/WPU composites were characterized by infrared spectroscopy, X-ray diffractometry and transmission electron microscopy etc. Their mechanical properties and wear resistance were analyzed as well. The experimental results showed that SGO was successfully grafted onto polyurethane macromolecule by an in situ method and, with the introduction of sulfonic groups, the interfacial compatibility of GO and PU was improved significantly so that SGO evenly dispersed into WPU. The SGO that was grafted onto WPU macromolecules exhibited layered morphology with nanometers in the WPU matrix. With increasing SGO content, the tensile strength and the wear resistance of the film increased, but the addition of more than 0.8 wt % SGO yielded unfavorable results. When the added amount of SGO was 0.8 wt % of WPU, the tensile strength of the composite film was 46.53% higher than that of the blank group, and the wear resistance of the film was remarkably improved, which was due to a strong interaction between the SGO and WPU phases. Thus, the conclusion can be drawn that appropriate amount of SGO addition can enhance the mechanical properties of SGO/WPU composite film.

Enhancement of hydrophilicity and the resistance for irreversible fouling of polysulfone (PSF) membrane immobilized with graphene oxide (GO) through chloromethylated and quaternized reaction

A novel graphene oxide (GO) immobilized quaternized polysulfone (PSF) hybrid membrane (Q-PSF/GO) was prepared via phase inversion method using GO as an additive, and triethanolamine (TEOA) as an aminated agent. TEOA, which reacted with both PSF and GO, could improve the dispersibility and compatibility of GO in membrane casting solution. The membrane exhibited highest permeability and rejection rate to bovine serum albumin (BSA) compared to bare PSF membrane and PSF/GO membrane. Expressly, when the same amount of GO was incorporated into the PSF/GO membrane and the Q-PSF/GO membrane, the Q-PSF/GO membrane showed a more satisfactory performance. The water contact angle measurement confirmed the increased hydrophilicity of the Q-PSF/GO hybrid membrane. FE-SEM images proved that the Q-PSF/GO0.5 membrane possessed larger and more vertical finger-like pore structure in comparison with bare PSF membrane and PSF/GO membrane. Furthermore, it was proved by CLSM images that a thick and incompact layer of BSA was absorbed onto the surface of the Q-PSF/GO0.5 membrane. However, the absorbed layer of BSA on Q-PSF/GO0.5 membrane surface could be easily washed away compared to the bare PSF membrane.

In It for the Long Haul: The Cytocompatibility of Aged Graphene Oxide and Its Degradation Products.

Synthetic biomaterials are poised to transform medicine; however, current synthetic options have yet to ideally recapitulate the desirable properties of native tissue. Thus, the development of new synthetic biomaterials remains an active challenge. Due to its excellent properties, including electrical conductivity, water dispersibility, and capacity for functionalization, graphene oxide (GO) holds potential for myriads of applications, including biological devices. While many studies have evaluated the compatibility of freshly prepared GO, understanding the compatibility of GO as it ages in an aqueous environment is crucial for its safe implementation in long-term biological applications. This is a critical disconnect, as GO has been shown to undergo an autodegradation pathway in aqueous conditions, dynamically changing its composition and structure while producing degradation products. Thus, the long-term cytocompatibility of GO is investigated by "aging" GO over time in water and accelerating aging and decomposition via sonication. While age affects the composition and size of GO, it has no effect on cellular vitality and does not alter subcellular structures or DNA melting. Overall, GO is cytocompatible throughout the process of aging, beginning to demonstrate that GO may be utilized for long-term in vivo applications such as implanted tissue engineered scaffolds or biosensors.

Graphene oxide as a scaffold for bone regeneration.

Graphene oxide (GO), the oxidized form of graphene, holds great potential as a component of biomedical devices, deriving utility from its ability to support a broad range of chemical functionalities and its exceptional mechanical, electronic, and thermal properties. GO composites can be tuned chemically to be biomimetic, and mechanically to be stiff yet strong. These unique properties make GO-based materials promising candidates as a scaffold for bone regeneration. However, questions still exist as to the compatibility and long-term toxicity of nanocarbon materials. Unlike other nanocarbons, GO is meta-stable, water dispersible, and autodegrades in water on the timescale of months to humic acid-like materials, the degradation products of all organic matter. Thus, GO offers better prospects for biological compatibility over other nanocarbons. Recently, many publications have demonstrated enhanced osteogenic performance of GO-containing composites. Ongoing work toward surface modification or coating strategies could be useful to minimize the inflammatory response and improve compatibility of GO as a component of medical devices. Furthermore, biomimetic modifications could offer mechanical and chemical environments that encourage osteogenesis. So long as care is given to assure their safety, GO-based materials may be poised to become the next generation scaffold for bone regeneration. WIREs Nanomed Nanobiotechnol 2017, 9:e1437. doi: 10.1002/wnan.1437 For further resources related to this article, please visit the WIREs website.

In vivo compatibility of graphene oxide with differing oxidation states.

Graphene oxide (GO) is suggested to have great potential as a component of biomedical devices. Although this nanomaterial has been demonstrated to be cytocompatible in vitro, its compatibility in vivo in tissue sites relevant for biomedical device application is yet to be fully understood. Here, we evaluate the compatibility of GO with two different oxidation levels following implantation in subcutaneous and intraperitoneal tissue sites, which are of broad relevance for application to medical devices. We demonstrate GO to be moderately compatible in vivo in both tissue sites, with the inflammatory reaction in response to implantation consistent with a typical foreign body reaction. A reduction in the degree of GO oxidation results in faster immune cell infiltration, uptake, and clearance following both subcutaneous and peritoneal implantation. Future work toward surface modification or coating strategies could be useful to reduce the inflammatory response and improve compatibility of GO as a component of medical devices.