Graphene Oxide Nanomaterials Research Articles

Investigation on piezoresistive properties of reduced graphene oxide treated glass textiles based multifunctional sensors

AbstractGlass fabric‐reinforced composites (GFRC) and other revolutionary engineered materials find extensive application in the aerospace, construction, and automobile sectors. It is challenging to predict damage under real‐time stresses due to the anisotropic behavior of composite materials. This study presents the development of a glass textile‐based multifunctional composite sensor and demonstrates its application as a change in resistance or gauge factor in structural health monitoring (SHM) systems. This sensor is coated with reduced graphene oxide (rGO) nanomaterial. Its electrical resistance is evaluated by examining the concentration of nanoparticles and varying geometrical parameters. A three‐point bending method assessed the piezoresistive behavior of the integrated sensor in the GFRC. The impact of sensor width and relative placements in the material's thickness direction within the composite samples is evaluated. Cyclic flexural testing was also performed to demonstrate real‐world applications. The research concludes that it can be utilized as a damage assessment technique for GFRC. The developed sensor can be used to provide an electrically conductive path or as a resistor in the field of E‐textiles. The developed piezoresistive sensor has the flexibility to be used as a multifunctional sensor for multiple purposes, such as force, torque, weight, pressure, flow, acceleration sensors, etc.Highlights Glass textile‐based multifunctional materials are reported as strain‐monitoring sensors. Tailored sensor resistance could be achieved through rGO current conduction paths. Glass textile‐based sensors could potentially be used in the field of E‐textile.

Effects of Iron Ion Ratios on the Synthesis and Adsorption Capacity of the Magnetic Graphene Oxide Nanomaterials

Effects of Iron Ion Ratios on the Synthesis and Adsorption Capacity of the Magnetic Graphene Oxide Nanomaterials

Enhancing diesel engine performance and emissions control with reduced Graphene oxide and Non-Edible biodiesel blends

The growing concern about environmental degradation and the depletion of fossil fuel supplies has prompted experts to investigate alternate and sustainable transportation energy sources. In these circumstances, biodiesel made from renewable feedstock has emerged as a viable environmentally friendly alternative to conventional diesel. This study thoroughly examines the performance and emission characteristics of a 4-stroke diesel engine running on biodiesel blends, including reduced graphene oxide (rGO) nanomaterial. The non-edible biodiesel from the Jatropha curcas plant is utilized, and it is blended in various ratios with conventional diesel, ethanol, and nanomaterial rGO to improve performance and emissions parameters. Torque increased by up to 17 % in rGO DJE02GO25 at 3500 rpm, while Brake Power decreased by 6.3 % in rGO DJE01GO25 at 2600 rpm. Brake Thermal Efficiency decreased by 12.5 % in rGO Blend 1 at 2600 rpm, and Brake-specific fuel consumption decreased by 16.5 % in rGO DJE02GO25 at 3500 rpm. CO2 emissions decreased up to 19.71 % in rGO Blend 10 at 2600 rpm. HC emissions decreased to 94 % in rGO blend 8 at 3500 rpm. Finally, NOx emissions decreased up to 84.78 % in rGO Blend 1 at 2900 rpm. The current study reveals that after adding rGO nanomaterial in biodiesel, there is a significant decrease in NOx and HC emissions.

Augmenting interfacial solar steam generation using 3D-printed hollow honeycomb structured pattern filled with rGO decorated natural fibres

In the present study, a hollow honeycomb structured (HHS) pattern is fabricated using fusion deposition modelling and filled with different natural fibres namely sugarcane (SC) and cotton sponge (CS). It is then called HHS-SC and HHS-CS interfacial solar evaporators. In addition, reduced graphene oxide (rGO) nanomaterial is coated on the top evaporative surface of the developed evaporators to investigate the performance of interfacial solar steam generation (ISSG). During experimentation, HHS-CS/rGO evaporator exhibits better performance than HHS-SC/rGO evaporator. At indoor conditions, mass loss of water (MW), evaporation flux (EF) and evaporation efficiency (EE) of the HHS-CS/rGO evaporator are 2.0 g, 3.493 kg/m2h and 84.04 % respectively. Consequently, the MW, EF and EE are 6.2 g, 1.35 kg/m2h and 61.29 % respectively at outdoor conditions. Results show that (i) the reduction in the size of porosity and improved capillary action of CS (ii) the super hydrophilicity nature of CS increases the water transportation (iii) the poor thermal conductivity of CS (iv) the higher thermal conductivity of rGO aids in trapping the sunlight. The stability and repeatability of the HHS-CS/rGO evaporator are investigated and found to be excellent for 8 repetitive cycles. Additionally, the prepared interfacial solar evaporator results better performance in dye molecule separation and salt water purification and hence, this can be recommended for commercial applications.

Enhanced piezocatalytic degradation of cationic dyes using graphene oxide and magnetic beads Nanomaterials: Synthesis, Characterization, and mechanistic insights

Sequestration of organic pollutants by the method of degradation is one of the safest ways to completely remove them from water bodies, without generating harmful by-products. Piezocatalytic degradation for this approach has been gaining much research attention, in recent times, due to its high efficiency. The present work reports synthesis of four types of Graphene Oxide-Chitin-Magnetic Iron Oxide Beads Nanomaterials, each with a different ratio of Graphene oxide (GO) and Chitin (CH). Among these, GO-CH-MIOBs NM-4 showed a superior Piezocatalytic degradation capacity towards methylene blue (MB), crystal violet (CV) and Rhodamine 6G (R6G) dyes. Various parameters influencing the piezocatalytic performance of the material such as kinetic factors, initial dye concentration, strength of ultrasonic vibration etc., have been analyzed thoroughly. Degradation rate constant (K) values of 63.4, 59.34 and 48.36 /min were obtained for MB, CV and R6G Dyes respectively. Moreover, cycling tests for all three dyes reflected significant stability of these materials as evident from the high degradation efficiencies of 99.80, 99.24 and 99.12 % within 60 min being retained for MB, CV and Rh6G dyes even after the 5th cycle. These nanomaterials can be a good addition in the list of high efficiency piezocatalyts for water purification with no secondary wastes being produced. Comparison of the XPS spectra before and after sonication gave insight into the mechanism of piezocatalytic degradation which highlighted hydroxyl and superoxide radicals as the main attacking species which are responsible for the degradation process.

Microbial response to the chronic toxicity effect of graphene and graphene oxide nanomaterials within aerobic granular sludge systems

Nanomaterials present in wastewater can pose a significant threat to aerobic granular sludge (AGS) systems. Herein, we found that compared to graphene nanomaterials (G-NMs), the long-term presence (95 days) of graphene oxide nanomaterials (GO-NMs) resulted in an increased proliferation of filamentous bacteria, poorer sedimentation performance (SVI30 of 74.1 mL/g) and smaller average particle size (1224.4 µm) of the AGS. In particular, the GO-NMs posed a more significant inhibitory effect to the total nitrogen removal efficiency of AGS (decreased by 14.3 %), especially for the denitrification process. The substantial accumulation of GO-NMs within the sludge matrix resulted in a higher level of reactive oxygen species in AGS compared to G-NMs, thereby inducing lactate dehydrogenase release, and enhancing superoxide oxidase and catalase activities. Such excessive oxidative stress could potentially result in a significant reduction in the activity of nitrogen metabolism enzymes (e.g., nitrate reductase and nitrite reductase) and the expression of key functional genes (e.g., nirS and nirK). Altogether, compared to G-NMs, prolonged exposure to GO-NMs had a more significant chronic toxicity effect on AGS systems. These findings implied that the presence of G-NMs and GO-NMs is a hidden danger to biological nitrogen removal and should receive more attention.

Improving Mud Brick Durability in Ancient Closed-Box Tombs: A Graphene Oxide Nanoparticle Approach

This paper presents a novel concept for significantly enhancing the strength and durability of ancient closed-box tombs. These tombs hold significant philosophical values, and their architecture serves as a valuable data source, providing insights into the cultural stage of the society in which it was constructed. Throughout medieval and modern times, clay bricks remained a prevalent material for tomb construction due to their affordability and design flexibility. However, these structures currently face neglect and weakening, requiring imperative intervention of protection to prevent them from potential deterioration or extinction. The key objective of this research is to explore the potential use of graphene oxide (GO), a novel nanomaterial, as a treatment method to enhance the durability of mud brick tombs in Aswan, Egypt. Samples of mud bricks were examined and characterized using various techniques, including SEM-EDX, TEM, PLM, XRF, XRD, and mechanical properties analysis. The results indicated that GO nanomaterials significantly improve the mechanical properties of mud brick tombs, allowing them to resist more compressive loading and ultimately resulting in more durable and long-lasting structures. By using these innovative materials, effective restoration and preservation of these ancient structures for future generations could be viable. This research has the potential to revolutionize the preservation of closed-box tombs, ensuring these historical landmarks stand longer the test of time.

Dissecting the interaction between Graphene Oxide and Human Transferrin via biophysical, biochemical and in-silico approaches: Implications for nanomaterial anti-fibrillation properties and protein structure

Human Transferrin (HTF) plays a pivotal role in numerous neurological therapies by carrying drugs and nanomaterials through the challenging blood-brain barrier. Nonetheless, the binding of HTF with highly relevant nanomaterials is not fully comprehended. Here, the nanomaterial graphene oxide (GO) has been obtained and their interaction with HTF in the native and fibrillar form has been investigated, by employing multi-spectroscopic, modeling, and microscopic techniques. The fluorescence results reveal that GO quenches the HTF intrinsic fluorescence by following a mix of static and dynamic mechanisms, and the GO-HTF complex formation has been confirmed by UV-Vis spectroscopy. Additionally, HTF attaches firmly to GO (KS≈ 106M−1) through mainly by hydrophobic and hydrogen bonds (according to determined ΔH=-23.77±1.03 kJ.mol−1 and ΔS= +39.53 ± 1.69 J.mol−1.K−1). Further, the in-silico investigation has evidenced the residues and chemical groups involved in HTF-GO interaction. Furthermore, SEM images reveal the formation and inhibition of HTF aggregates by GO, and spectroscopic methods reveal the related protein structural modification involved in the fibrillation process. In summary, all the results open questions concerning GO use for many neurological therapies.

Evaluating the Impact of Sonication Process on Graphene Oxide Structural Properties

Graphene oxide (GO) is one of the members of carbon-based nanomaterials and can be featured as graphene structure decorated with various oxygenated functional groups. Recently, various methods have been found for producing carbon-based nanomaterials with enhanced efficiency in several applications. The chemical process involves oxidizing graphite to GO using a powerful oxidizing chemical. Hummers method is one of the most known and versatile method for the production of GO nanomaterials because of its ease of application, parameter controllability and high yield. This process enables graphite oxidation and exfoliation into single- or multi-layered GO sheets. Exfoliation, the separation of graphene or graphitic layers, is a critical process in GO synthesis. Since exfoliation separates multilayered graphite oxide flakes or particles, it forms single layer GO by forcing oxidizing agents or solvent molecules between layers. The sonication process can exfoliate the oxidized layers, resulting in the formation of GO structure when the exfoliated layers consist of only one or a few layers of carbon atoms. Therefore, sonication procedure is among the key parameters of Hummers method that influences the characteristics of GO-based nanomaterials. In this study, the impact of sonication duration time and power parameters on morphological and structural characteristics of GO development was examined. For this purpose, characterization studies were performed by using Scanning electron microscope (SEM), X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), UV-Vis spectroscopy and Raman spectroscopy analysis. The findings revealed that the increase in sonication power and time led to an increase in defects in the resulting GO structure.

Synthesis and investigation of acrylamide and 2-acrylamido-2-methylpropanesulfonic acid copolymer-modified graphene oxide nanomaterials with intensive viscosification capacity: An experimental and molecular dynamics study

The polymer-modified nanomaterials with spontaneously generated cross-linked network greatly improve the dispersion viscosity, which is crucial for extending the sweep range and enhancing oil recovery. Recently, graphene oxide (GO) nanosheets have attracted extensive attention due to their high chemical reactivity and specific surface. In this paper, the AA molecule, synthesized by acrylamide (AM) and 2-acrylamido-2-methypropanesulfonic acid (AMPS) copolymerization, modified GO nanosheets (GAA) material is firstly synthesized and characterized. With the same content of AMPS segments, GAAn systems consistently exhibit better dispersion stability than AAn systems, along with higher absolute zeta potential values. The comprehensive investigation on the rheological property of GAA system reveals that GAA15 with the highest AMPS content exhibits the largest zero-shear viscosity (409.27 mPa·s) and the longest relaxation time. Based on the molecular dynamic simulation approaches, the aggregation morphology and stability of AA and GAA molecules are evaluated via the configuration analysis and the statistics of hydrogen bond numbers. The abundant binding sites from GO segments of GAA promote additional hydrogen bonds between GAA molecules and water, resulting in a more stable configuration. Molecular surface potential analysis and the independent gradient model based on Hirshfeld partition (IGMH) methods are further used to visualize the non-bonded interaction existed in cross-linked networks, which also predict and validate non-bonding interaction sites among molecular segments. The simulation results indicate higher viscosity in the GAA system should be ascribed to the formation of dispersion-strengthened cross-linked structures (AM-GO plane and GO-GO stacking segments). In summary, the microscopic viscosity-increasing mechanism of novel GAA system is proposed from the perspective of intermolecular interactions, which lays a preliminary theoretical foundation for the application of GAA material in the oil industry.

Transport of polystyrene microplastics in bare and iron oxide-coated quartz sand: Effects of ionic strength, humic acid, and co-existing graphene oxide

This research explored the effects of widely utilized nanomaterial graphene oxide (GO) and organic matter humic acid (HA) on the transport of microplastics under different ionic solution strengths in bare sand and iron oxide-coated sand. The results found transport of polystyrene microplastics (PS) did not respond to the presence of HA in sand that contains large amounts of iron oxide. Compared to bare quartz sand, ionic strength had little effect: <20 % of PS passed through Fe sand columns. There was a significant promotion of PS transport in the presence of GO, however, which can be attributed to the increased surface electronegativity of PS and steric hindrance. Moreover, GO combined with HA significantly promoted the transport of PS in the Fe sand, and transport further increased when the concentration of HA increased from 5 to 10 mg/L. Interestingly, the degree of this increase exactly corresponded to the change in the surface charge of the microplastics, demonstrating that electrostatic interaction dominated the PS transport. Further results indicated that co-existing pollutants had significant impacts on the transport of microplastics under various conditions by altering the surface characteristics of the plastic particles and the spatial steric hindrance within porous media. This research will offer insights into predicting the transport and fate of microplastics in complex environments.

Effects of reduced graphene oxide nanomaterials on transformation of 14C-triclosan in soils

Increasing use and release of graphene nanomaterials and pharmaceutical and personal care products (PPCPs) in soil environment have polluted the environment and posed high ecological risks. However, little is understood about the interactive effects and mechanism of graphene on the behaviors of PPCPs in soil. In the present study, the effects of reduced graphene oxide nanomaterials (RGO) on the fate of triclosan in two typical soils (S1: silty loam; S2: silty clay loam) were investigated with 14C-triclosan, high-resolution mass spectrometry, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), density functional theory (DFT) calculations, and microbial community structure analysis. The results showed that RGO prolonged the half-life of triclosan by 23.6–51.3 %, but delayed the formation of transformed products such as methyl triclosan and dechlorinated dimer of triclosan in the two typical soils. Mineralization of triclosan to 14CO2 was inhibited by 48.2–79.3 % in 500 mg kg−1 RGO in comparison with that in the control, whereas the bound residue was 54.2–56.4 % greater than the control. RGO also reduced the relative abundances of triclosan-degrading bacteria (Pseudomonas and Sphingomonas) in soils. Compared to silty loam, RGO more effectively inhibited triclosan degradation in silty clay loam. Furthermore, the DFT calculations suggested a strong association of the adsorption of triclosan on RGO with the van der Waals forces and π-π interactions. These results revealed that RGO inhibited the transformation of 14C-triclosan in soil through strong adsorption and triclosan-degrading bacteria inhibition in soils. Therefore, the presence of RGO may potentially enhance persistence of triclosan in soil. Overall, our study provides valuable insights into the risk assessment of triclosan in the presence of GNs in soil environment.

Performance Evaluation Using Graphene Oxide Nanomaterial as a Nano-Lubricant for R600a Refrigeration Systems

Performance Evaluation Using Graphene Oxide Nanomaterial as a Nano-Lubricant for R600a Refrigeration Systems

Effect of Graphene Oxide Nanomaterials on the Durability of Concrete: A Review on Mechanisms, Provisions, Challenges, and Future Prospects.

This review focuses on recent advances in concrete durability using graphene oxide (GO) as a nanomaterial additive, with a goal to fill the gap between concrete technology, chemical interactions, and concrete durability, whilst providing insights for the adaptation of GO as an additive in concrete construction. An overview of concrete durability applications, key durability failure mechanisms of concrete, transportation mechanisms, chemical reactions involved in compromising durability, and the chemical alterations within a concrete system are discussed to understand how they impact the overall durability of concrete. The existing literature on the durability and chemical resistance of GO-reinforced concrete and mortar was reviewed and summarized. The impacts of nano-additives on the durability of concrete and its mechanisms are thoroughly discussed, particularly focusing on GO as the primary nanomaterial and its impact on durability. Finally, research gaps, future recommendations, and challenges related to the durability of mass-scale GO applications are presented.

Noninvasive PCA3 detection for screening prostate diseases using a graphene oxide-based method

Prostate Cancer Associated 3 (PCA3) as a promising biomarker to replace serum prostate-specific antigen (PSA) for differential diagnosis of benign and malignant prostate diseases. However, the detection of PCA3 in urine requires the collection of digital rectal examination (DRE) urine, which limits the application of PCA3 in screening prostate diseases. In the present study, a new reverse transcription quantitative real-time polymerase chain reaction (qRT-PCR) method was developed for PCA3 detection in non-DRE urine. The method uses the nanomaterial Graphene oxide (GO) to effectively prevent nonspecific amplification in qRT-PCR. GO-based qRT-PCR produced no nonspecific amplification. Receiver operating characteristic curve (ROC) results showed that the area under curve (AUC) of PCA3 to discriminate normal control subjects from prostate cancer (PCa) was 0.869 (95% confidence interval [CI], 0.689–1.000), and using 2.711 as the cutoff value of PCA3, the sensitivity was 81.8% and the specificity was as high as 88.9%. For prostatitis (PTIS) and PCa, the AUC value of PCA3 to distinguish them was 0.636 (95% CI, 0.396–0.877), with 81.8% sensitivity and 58.3% specificity. Compared with the 8.3% specificity of PAS, the specificity of PCA3 was improved by 50%, which suggested that PCA3, in non-DRE urine, has a significant potential application in the differential diagnosis of prostate diseases.

Multifunctional Self-Assembled Block Copolymer/Iron Oxide Nanocomposite Hydrogels Formed from Wormlike Micelles.

This article reports the preparation of multifunctional magnetic nanocomposite hydrogels formed from wormlike micelles. Specifically, iron oxide nanoparticles were incorporated into a temperature responsive block copolymer, poly(glycerol monomethacrylate)-b-poly(2-hydroxypropyl methacrylate) (PGMA-b-PHPMA), and graphene oxide (GO) dispersion at a low temperature (∼2 °C) through high-speed mixing and returning the mixture to room temperature, resulting in the formation of nanocomposite gels. The optimal concentrations of iron oxide and GO enhanced the gel strength of the nanocomposite gels, which exhibited a strong magnetic response when a magnetic field was applied. These materials retained the thermoresponsiveness of the PGMA-PHPMA wormlike micelles allowing for a solid-to-liquid transition to occur when the temperature was reduced. The mechanical and rheological properties and performance of the nanocomposite gels were demonstrated to be adjustable, making them suitable for a wide range of potential applications. These nanocomposite worm gels were demonstrated to be relatively adhesive and to act as strain and temperature sensors, with the measured electrical resistance of the nanocomposite gels changing with applied strain and temperature sweeps. The nanocomposite gels were found to recover efficiently after the application of high shear with approximately 100% healing efficiency within seconds. Additionally, these nanocomposite worm gels were injectable, and the addition of GO and iron oxide nanomaterials seemed to have no significant adverse impact on the biocompatibility of the copolymer gels, making them suitable not only for 3D printing in nanocomposite engineering but also for potential utilization in various biomedical applications as an injectable magnetic responsive hydrogel.

A critical review on the effect of graphene oxide in fiber reinforced cementitious systems

The most widely used building materials nowadays are aggregates and cementitious material composites. Recently, the Graphene Oxide (GO) nanomaterial has grabbed a lot of attention in the material science of building materials. These graphene oxide-based cementitious composites have been studied in terms of their effect on microstructure, hydration mechanisms, mechanical and durable properties, as well as the performance of GO-cement composites, which transform ordinary cement materials into intelligent, sturdy, and long-lasting composites. An overview of the contemporary state-of-the-art effect of cementitious composites containing GO with fiber addition is presented in this paper. The main purpose of this paper is to critically review GO's performance with fibers in cementitious composites. In this review, we examined the properties like Workability, mechanical properties, and durability of cement-based materials along with the microstructural characterization. The tailored property of cementitious composite made with graphene oxide and fibers controls not only the secondary hydration mechanism but also improves the material’s mechanical performance, robustness and other multifunctional properties. The interaction of GO nanomaterial with fiber results in a remarkable and unique performance, such as the improvement of gel pores, the decrease of bigger capillary pores, the bridging of microcracks and the resistance to their spread, and the overall performance improvement of cementitious composites. Thus, this article aims to provide a substantial critical review of the impact of GO and fibers in cementitious composites.

Enhanced sensing of bacteria biomarkers by ZnO and graphene oxide decorated PEDOT film

Developing a biofilm biomarker detector and inhibitor will immensely benefit efforts geared at curbing infectious diseases and microbiologically induced corrosion of medical implants, marine vessels and buried steel pipelines. N-Acyl homoserine lactones (AHLs) are important biomarkers gram-negative bacteria use for communication. In this work, we investigated the interactions between three AHL molecules and graphene oxide (GO) and ZnO nanomaterials embedded in conjugated poly(3,4-ethylenedioxythiophene) (PEDOT) film. The results show that PEDOT/GO/ZnO detected AHLs to a considerable extent with adsorption enthalpies of −4.02, −4.87 and −4.97 KJ/mol, respectively, for N-(2-oxotetrahydrofuran-3-yl)heptanamide (AHL1), 2-hydroxy-N-(2-oxotetrahydrofuran-3-yl)nonanamide (AHL2) and (E)-3-(3-hydroxyphenyl)-N-(2-oxotetrahydrofuran-3-yl)acrylamide (AHL3) molecules. The ZnO nanoparticles facilitated charge redistribution and transfer, thereby enhancing the conductivity and overall sensitivity of the substrate toward the AHLs. The adsorption distance and sites of interactions further tuned the charge migration and signal generation by the substrate, thus affirming the suitability of the modeled thin film as a sensor material. Excellent stability and conductivity were maintained before and after the adsorption of each AHL molecule. Moreover, the desorption time for each AHL molecule was calculated, and the result affirmed that the modeled film materials are promising for developing highly sensitive biosensors. Communicated by Ramaswamy H. Sarma

Evaluation of sol-gel and solvothermal method on titanium dioxide and reduced graphene oxide nanocomposite

The present study compares two synthesis routes to obtain titanium dioxide and reduced graphene oxide nanocomposites that could be used as photoelectrodes in a water-splitting photoelectrocatalytic system. The nanocomposites were obtained using in-situ sol-gel and solvothermal methods as fabrication routes. Subsequently, the materials obtained were characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, and ultraviolet-visible diffuse reflectance spectroscopy techniques. The results indicated a strong interaction between reduced graphene oxide and titanium dioxide nanomaterials using both synthesis processes; however, the in-situ sol-gel method exhibited more significant conservation of the aromatic rings of the graphene structure and a lower bandgap (2.45 eV), which are suitable characteristics for its potential use in photoelectrocatalytic processes.

First-in-human controlled inhalation of thin graphene oxide nanosheets to study acute cardiorespiratory responses

Graphene oxide nanomaterials are being developed for wide-ranging applications but are associated with potential safety concerns for human health. We conducted a double-blind randomized controlled study to determine how the inhalation of graphene oxide nanosheets affects acute pulmonary and cardiovascular function. Small and ultrasmall graphene oxide nanosheets at a concentration of 200 μg m−3 or filtered air were inhaled for 2 h by 14 young healthy volunteers in repeated visits. Overall, graphene oxide nanosheet exposure was well tolerated with no adverse effects. Heart rate, blood pressure, lung function and inflammatory markers were unaffected irrespective of graphene oxide particle size. Highly enriched blood proteomics analysis revealed very few differential plasma proteins and thrombus formation was mildly increased in an ex vivo model of arterial injury. Overall, acute inhalation of highly purified and thin nanometre-sized graphene oxide nanosheets was not associated with overt detrimental effects in healthy humans. These findings demonstrate the feasibility of carefully controlled human exposures at a clinical setting for risk assessment of graphene oxide, and lay the foundations for investigating the effects of other two-dimensional nanomaterials in humans. Clinicaltrials.gov ref: NCT03659864.