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Abstract Delivering anticancer drugs to the appropriate site within the body poses a critical challenge in cancer treatment with chemotherapeutic agents like doxorubicin (DOX). Magnetic graphene oxide (GO) nanosheets with generation 1 (G1) amidoamine-dendronized crosslinks were developed by coupling cystamine-functionalized GO nanosheets with Fe3O4 nanoparticles modified with primary amine and methyl acrylate. These magnetic GO nanosheets were loaded with DOX to create a dual pH- and redox-responsive delivery system for cancer chemotherapy. The prepared magnetic nanosheets underwent characterization using FTIR, XRD, DLS, VSM, FE-SEM, and TEM. Physical DOX adsorption was evaluated using various isotherms, including Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich. The in-vitro release profiles of DOX from the magnetic nanosheets were studied under different pH conditions, with and without glutathione (GSH), and the drug release data were fitted with various kinetic models. Additionally, an MTT assay was employed to assess the compatibility and antitumor activity of DOX-loaded magnetic nanosheets in the HepG2 cell line. The results showed that the maximum drug loading was 13.1% (w/w) at a drug/carrier ratio of 1. Without GSH addition, the maximum drug release after 10 days was only 17.9% and 24.1% at pH 7.4 and 5.3, respectively. However, in the presence of GSH, the maximum drug release reached 51.7% and 64.8% at pH 7.4 and 5.3, respectively. Finally, the research findings suggest that the magnetic nanosheets exhibited pH- and redox-stimuli drug release, high biocompatibility, and superior antitumor activity compared to free DOX.

Abstract The antibacterial characteristics of graphene oxide (GO-SB) nano-sheets generated by charring sugarcane bagasse (SB) are described in this study. The antibacterial capability of GO-SB was improved when it was grafted with ethyl cellulose (EC) and polyvinyl alcohol (PVA) to form GO-SB/EC/PVA hydrogels. Characterization of GO-SB nanosheets and GO-SB/EC/PVA hydrogels was accomplished by using FTIR, SEM, XRD, and thermal studies. The antimicrobial activity was carried out against Gram positive bacteria [Micrococcus leutus & Staphylococcus aureus], Gram negative bacteria [Escherichia coli, Pseudomonas aeruginosa] and pathogenic fungal yeast [Candida albicans] applying the disc diffusion method. The disc diffusion method results showed that the improved GO-SB/EC/PVA exhibited a reasonable level of antimicrobial capability against Micrococcus leutus, demonstrating that the antimicrobial improvement of GO-SB was more effective in the GO-SB/EC/PVA hydrogels by increasing the inhibition zone of Gram-positive bacteria, Micrococcus leutus from (13.0 to 16.0 mm). Graphical abstract

This review is mainly on the relevance of graphene aerogels for energy storage systems highlighting their distinct properties and applications. Today, electronic devices such as smartphones, laptops, and other electrical appliances have become the axe of our daily lives. As a result, electrical energy is required for these devices. Despite the discovery of renewable energy sources as an alternative to fossil fuels, the construction of energy storage systems is still necessary to store energy. Lithium-ion batteries and supercapacitors are considered essential systems for this purpose and have witnessed tremendous development in recent years. The efficiency of these systems depends on the structure of the materials used in their formation. Graphene oxide and graphene aerogel materials improve the properties of energy storage systems in terms of stability of charging and discharging cycles, longevity, and reduction of combustion incidents resulting from ordinary compounds. However, the development of graphene aerogels faces challenges in improving their mechanical properties, the cost of their preparation, and their high agglomeration ability in solvents. Therefore, intensive efforts are needed to develop these materials for a new revolution in energy storage.

This study introduces a novel silica-graphene oxide@chitosan (SiGO@CS) material as a packed biosorbent for microextraction by packed sorbent (MEPS), followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of pesticides (atrazine and thiamethoxam) and antibiotics (ceftiofur and sulfonamide) in food samples. The graphene-based aerogel was modified with varying percentages of silica-graphene oxide/chitosan (w/w) and characterized to confirm successful chitosan incorporation. Optimization of the MEPS protocol, using 24–1 and 23 experimental designs, identified draw/eject and washing cycles as the most influential parameters for extraction efficiency. The SiGO@CS biosorbent with 80 % CS/SiGO (w/w) exhibited superior extraction efficiency compared to other ratios and commercial sorbents. The method demonstrated excellent linearity for all analytes (R² > 0.9900), with low limits of detection (LOD) and quantification (LOQ) ranging from 0.020 to 0.045 µg l-1 and 0.045 to 1.0 µg l-1 for pesticides, respectively, and 5 to 15 µg l-1 and 15 to 20 µg l-1 for antibiotics, respectively. Trueness values were within 82 % to 109 %. The method's green credentials were confirmed using AGREEprep and the Green Analytical Procedure Index (GAPI) approach, highlighting sorbent reusability (over 15 times) and rapid analytical throughput (5 min per sample) with low use of pre-treated sample extract volume (500 µL). The application to local corn, tomato, and milk samples confirmed the detection and quantification of thiamethoxam and atrazine at concentrations above the recommended ingestion per day for one sample of tomato and corn out of the three samples analyzed. Furthermore, using the novel SiGO@CS biosorbent in the MEPS protocol offers a green, high-performance analytical alternative to traditional sorbent phases, with the potential for evaluating trace levels of pesticides and antibiotics in food matrices.

Pathogen-induced infections and the rise of antibiotic-resistant bacteria, such as Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), pose significant global health challenges, emphasizing the need for new antimicrobial strategies. In this study, we synthesized graphene oxide (GO)-based composites functionalized with silver nanoparticles (AgNPs) and copper nanoparticles (CuNPs) as potential alternatives to traditional antibiotics. The objective is to assess the antibacterial properties of these composites and explore their efficacy against E. coli and S. aureus, two common bacterial pathogens. The composites are prepared using eco-friendly and conventional methods to ensure effective nanoparticle attachment to the GO surface. Structural and morphological characteristics are confirmed through SEM, AFM, EDS, XRD, UV-vis, FTIR, and Raman spectroscopy. The antibacterial efficacy of the composites is tested through disk diffusion assays, colony-forming unit (CFU) counts, and turbidimetry analysis, with an emphasis on understanding the effects of different nanoparticle concentrations. The results demonstrated a dose-dependent antibacterial effect, with GO/AgNP-1 showing superior antibacterial activity over GO/AgNP-2, particularly at lower concentrations (32.0 μg/mL and 62.5 μg/mL). The GO/CuNP composite also exhibited significant antibacterial properties, with optimal performance at 62.5 μg/mL for both bacterial strains. Turbidimetry analysis confirmed the inhibition of bacterial growth, especially at moderate concentrations, although slight nanoparticle aggregation at higher doses reduced efficacy. Lastly, both GO/AgNP and GO/CuNP composites demonstrated significant antibacterial potential. The results emphasize the need to fine-tune nanoparticle concentration and refine synthesis techniques to improve their efficacy, positioning these composites as strong contenders for antimicrobial use.

One of the most important concerns around the world nowadays is the drinking water quality. Silver ions (Ag+) are one of the heavy metal ions that can seriously degrade the water quality and therefore, the human health. Hence, the World Health Organization (WHO) fixed the maximum acceptable concentration of these ions in drinking water at approximately 0.93 µM. Thus, the development of cost-effective and efficient techniques and tools that can help to quantify Ag+ ions in drinking water is of great importance. Herein, we used a new, simple, eco-friendly and low-cost synthesis route to synthesize a sustainable hybrid carbon material, namely sulfonated reduced graphene oxide@graphene oxide (S-rGO@GO) that was utilized as electrode material for Ag+ ions electroanalysis in drinking water. The successful synthesis of S-rGO@GO was evidenced by XRD, Raman spectroscopy, XPS, FE-SEM and EDX. The electrochemical characterization of S-rGO@GO revealed its good affinities towards Ag+ and its good electron transport abilities. The sensor prepared from S-rGO@GO (S-rGO@GO/GCE) showed good repeatability and reproducibility. S-rGO@GO/GCE optimization revealed that its best performance is achieved when 5 µL of 1 mg/mL of S-rGO@GO suspension in ultrapure water is used for its fabrication and when the electrodeposition (Ag+ to Ag0) is carried out at -0.1 V vs. SCE for 200 s. The calibration of S-rGO@GO/GCE exhibited a linear relationship in the concentration range of 0.2 to 1.4 µM, with a sensitivity of (0.605 ± 0.015) µA/µM; the statistic LOD was found to be 0.0007 µM. Furthermore, S-rGO@GO/GCE has shown a great potential for real samples analysis.

With the paramount development of industry and agriculture sector, levels of different pollutants like, heavy metal ions, pharmaceuticals, organic dyes, biological waste and other pollutants are becoming serious. The ecosystem and human health suffered greatly from the adverse effects of these pollutants. The disposal of these pollutants has become an urgent issue for the human society. Graphene oxide base nanocomposites have generated an excellent extent of focus as desirable alternatives for the adsorptive elimination of contaminants from aqueous systems owing to their enhanced surface area and multiple functional groups for adsorption. Graphene oxide (GO) as a graphene derivative exhibited superior features as obtainable in a graphene sheet. Moreover, the addition of oxygen functional group at the edges and basal plane of graphene further enhanced the efficiency of the graphene by providing sites for the attachment of different metals on the surface. On the underlying adsorption processes, graphene-based nanocomposites for specific contaminants are designed and currently employed for wastewater treatment. This review presents the ongoing development of GO base nanocomposites and their useful applications, understanding how well graphene-based nanocomposites adsorb pollutants and how that relates to the ways in which pollutants interact with adsorbents is crucial. This study highlights newly developed trends in the creation of graphene oxide based nanocomposites to eliminate different heavy metal ions, dyes, pharmaceuticals, and oils spills from effluent water. The focus is on various graphene oxides nanocomposites application for the removal of different pollutants and regeneration of graphene oxide base nanocomposites after several adsorption cycles. Other challenges and potential directions for designing efficient GO based nanocomposites as adsorbents are also presented along with the problems of current studies.

Novel bio-based electrode polyurethane (PU) fabricated using various conducting materials such as graphene oxide (GO), gold (Au), and carbon nanotube (CNT) as the primary source of a charge carrier. Initially, PU/GO, PU/Au, and PU/CNT polymers were synthesized using a pre-polymerization approach. Therefore, the application of conductive materials modifies and increases the conductivity of PU. The connection between PU and the conductive materials (GO, Au, and CNT) was identified using Fourier transform infrared (FTIR), whereby some important functional groups obtained in this spectrum investigation, such as the presence of amide (-NH) and carbonyl urethane(-C = O), following the absence of diisocyanate groups (-NCO) revealed the synthesis was satisfactory. The glass transition temperatures (Tg) of PU/GO, PU/Au, and PU/CNT were analyzed using differential scanning calorimetry (DSC). In contrast, the mass loss during the heat treatment was observed using thermogravimetric analysis (TGA). Furthermore, thermal studies have proven that PU/GO has higher thermal stability compared to PU/Au and PU/CNT. The field emission scanning electron microscopy (FESEM) presents satisfactory results between PU composites and pure PU. The conductivity of PU and PU composites was examined using electrochemical impedance spectroscopy (EIS) and showed that PU/GO has a better electrical conductivity (σ) at 3.68 × 10−3 S cm−1.

Bipolar disorder is commonly treated with lithium carbonate. The concentration of lithium in the blood serum should be closely monitored in patients who require long-term lithium therapy. To date, no colorimetric method of detecting lithium ions has been reported using nanosensors. We have developed a novel chemosensor based on nanozyme (NZ) to address this clinical need. The GO-Ag2O NZs were synthesized by a sonochemical method and used as a colorimetric nanosensor to detect lithium ions in human blood serum (Li (I)). To characterize NZs, various techniques were employed, including XRD, FTIR, TEM, FESEM, EDX, Raman spectroscopy, BET, DLS, Zeta potential, and ICP-OES. According to TEM and FESEM images of GO-Ag2O, the nanoparticles (NPs) of Ag2O are uniformly distributed on the surface of 2D graphene oxide sheets. In addition, silver oxide nanoparticles exhibited a cubic morphology with an average size of 3.5 nm. We have examined the performance of the NZs in an aqueous medium and in human blood serum that contains Li (I). A colorimetric test revealed that NZs synthesized in the presence of ultrasound were more sensitive to Li (I). According to the linearity of the calibration curves’ ranges, Li (I) has a limit of detection (LOD) of 0.01 µg/mL. Furthermore, it displayed a linear range between 0 and 12 µg/mL. GO-Ag2O NZs showed noticeable color changes from green to orange after exposure to Li (I). An incubation time of two minutes was found to be the most effective for sensing. This innovative approach provides a reliable method for monitoring lithium levels and ensuring patient safety during long-term lithium therapy for bipolar disorder.

Graphene oxide (GO) is a novel carbon material utilized extensively for diverse industrial applications. When exposed to environmental elements like sunlight and chlorination, GO can undergo a series of physical and chemical transformations, and its presence in water and the environment can endanger ecosystems. Therefore there is a need for methods that can effectively remove GO from water. Accordingly, we delve into the efficacy of basalt stone powder (BSP) as an adsorption medium for purifying aqueous solutions of GO. We examine the impact of various experimental parameters—namely pH, initial solution concentration, adsorbent mass, contact duration, and ambient temperature—on GO adsorption, employing the method of controlled variables. The adsorption efficacy is notably influenced by the pH level. At an acidic pH of 3, an initial GO concentration of 80 mg/L, an adsorbent dosage of 50 mg, and a temperature of 303 K (approximately 30 °C), the adsorption removal efficiency reaches an impressive 99 %, boasting a maximum adsorption capacity of 112 mg/g. Dynamically, the adsorption kinetics align most closely with a pseudo-first-order model, achieving equilibrium after 24 h. Thermodynamic analyses reveal that the Langmuir isotherm model most accurately describes the adsorption behavior, indicating an enhancement in BSP's adsorption capacity for GO as temperature rises. Based on thermodynamic equations, the adsorption of GO onto BSP is deduced to be a spontaneous process. Our findings illustrate BSP's considerable potential in the treatment and removal of GO from water, and therefore it may prove useful in environmental remediation efforts.

In this study, the graphene oxide and multi-walled carbon nanotubes fabrication was evaluated using (SEM), (FTIR), Raman spectroscopy and (XRD). The results showed promising accuracy for the graphene oxide and multi-walled carbon nanotubes voltammetric sensor. The direct voltammetric determination of Enalapril Maleate in pharmaceutical samples, urine, and serum is detailed using a straightforward and extremely sensitive technique. Graphene oxide-multiwall carbon nanotubes are added to glassy carbon electrodes in an efficient manner to activate the GO-MWNT structures, which then electrocatalyzes the reduction of Enalapril Maleate. The results of the cyclic voltammetric (CV) experiment showed that the electrocatalytic activity of GO-MWNTs to reduce Enalapril Maleate was significantly improved, leading to a much higher cathodic peak current for EM. This finding opens the door to the possibility of creating a very sensitive voltammetric sensor to detect EM in biological and pharmaceutical fluid samples. A linear calibration curve in the 2.5–12.5 ppm concentration range, a detection limit of 0.2 ppm, and a relative standard deviation (R.S.D.%) lower than 1.0 % (n = 5) were all indicative of ideal conditions. Lastly, EM is a diffusion-controlled process that proceeds through a two-electron-two-proton change, which provides a mechanism for the reduction of EM.. The GO-MWCNTs/GCE sensor had a good repeatability and excellent reproducibility, R.S.D.% =1.77 and 1.82.

Density functional theory (DFT) computation has been utilized to explore the effects of the transition metal oxides: CoO, CuO, NiO, and ZnO doping on the electronic properties, structural, and quantum capacitances of graphene oxide nanosheet. From the magnetic moment analysis CoO@GO was observed to have higher magnetic moment of 11.688 μB compared to the studied the transition metal oxide doped systems. Investigation into the electronic properties revealed that NiO@GO attained higher energy gap with value of 0.144 eV. It was observed that the GO O/C affects the bandgaps of the modelled systems. Perturbation theory analysis of fock matrix showed that CoO@GO and CuO@GO possessed higher second order stabilization energy with values 238.56 kcal/mol and 208.94 kcal/mol respectively. From the quantum capacitance studies, it was observed that the value of CQ for graphene oxide (GO) increased slightly from 72.276 µF/cm2 to ZnO@GO (121.550 µF/cm2) > NiO@GO (93.870 µF/cm2) > CoO@GO (90.52 µF/cm2) > CuO@GO (89.375 µF/cm2). The results obtained herein can provide an effective and simple new idea for the design of graphene-based supercapacitors that possess high energy density.

In the direction of developing new and reliable prognostic tools, metamaterial-based biosensor device is an emergent potential field. The special design of metamaterial provides signature frequency features of healthy or diseased tissues. In the current work we have studied the single split resonance device (SSR) using graphene oxide (GO) as probe for the accelerated and selective detection of bovine serum albumin (BSA). Further, we have used different band gap GO to interpret the structure-property relationship. Spectroscopy methods have been employed to further support the SSR results. 1 ppm solution of mGO-0.5 (band gap ∼1.35 eV) shows sequential increase in sensitivity on increasing amount of BSA. Figure-of-merit (FoM) of SSR biosensor also increased from 57 to 82 and highest Q-factor calculated for mGO-1 is ∼47 making it a good candidate as probe molecule. This work lays out a correlation of degree of GO functionalization with a physical parameter, i.e., band gap for activity towards protein molecules. Also, as the SSR devices use large wavelength radiation with high resolution and accuracy for quantitative estimation of analyte, these are potential non-invasive point-of-use portable diagnostic and early disease diagnosis devices.

The mechanism of using graphene oxide as a two-dimensional filler to increase the path length of the corrosive medium to the metal surface is limited to improving the corrosion resistance of the coating. This study propose novel dispersion and in-situ crosslinking reaction mechanism for constructing water-based heavy-duty anticorrosive coatings by using graphene oxide (GO) and waterborne epoxy resin (WEP). The results showed that GO can be uniformly dispersed directly into WEP without complex functional modifications. Oxygen-containing functional groups on moleculars structure of GO&WEP co-polymerized with diethylenetriamine (DETA) forming a continuous phase film which improved the density of the coating. Characterization techniques such as Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermal conductivity measurement instrument, pencil hardness tester, adhesion tester, salt spray corrosion test chamber, and electrochemical impedance spectroscopy (EIS) were used to evaluate coating structure and performance properties. The results showed that graphene characteristics enhanced physical properties and anti-corrosion performance of composite coatings. The construction mechanism of the coating is different from that of the current GO modified and dispersed in the coating as a two-dimensional filler to extend the path length of the corrosive medium to the metal surface. The coatings prepared by adding the optimum mass ratio of 0.1–0.2 % GO to WEP have the best physical properties and anti-corrosion properties. When the GO content is 0.2 wt%, the thermal conductivity increases by 86.0 %. After added 0.025 wt% GO, the coating hardness is increased by two grades directly from 2B to HB. With the addition of GO concentration increased to 0.05 wt%, the adhesion is increased from 2 to level 1.When the GO content exceeds 0.05 %, the coating will not bulge off after 4 months of salt water immersion experiment.

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.

Biopolymer composites represent an emerging alternative to petroleum-derived polymers for applications in electronic devices. Cellulose from Luffa cylindrical was treated with acid, and graphene oxide was produced from waste battery rod graphite. The two products were characterized using FTIR, SEM, TGA and XRD. After that, starch-based bioplastic films with varying amounts of acid-treated cellulose (ALC-cellulose) and graphene oxide (GO) as fillers were prepared, and the physical and electrical properties were determined. XRD data revealed a crystallinity of 62% for the ALC-cellulose and 52% for the cellulose precursor. GO had a d-spacing of 0.76 nm compared to 0.29 nm for battery-sourced graphite. TEM micrograph analyses revealed an average fibre diameter of 44.7 nm for acid-treated cellulose and 99.7 nm for cellulose. The density, thickness, opacity, and tensile strength of the bioplastic films increased from 1.31 to 1.44 g/cm3, 0.21–0.48 mm, 14.78–38.64, and 0.98–1.42 MPa, respectively, while the moisture content, swelling ability, and porosity reduced, with an increase in percentage composition of the filler materials. The dielectric constant and conductivity increased from 50.3 to 6965.2 and 0.0036–0.0147 S/m with an increase in percentage composition of the filler materials except for Filmcr4, which showed a drop in dielectric constant (3033.73) and conductivity (0.0074 S/m). Overall, this study has demonstrated that bioplastic filler materials can be sourced from waste materials and that these fillers improved the starch-based bioplastic film's physical and electrical properties.

The self-assembly of graphene oxide (GO) and M13 bacteriophage results in the formation of micro-porous structures, known as GraPhage13 aerogels (GPA). Given the limited applications of aerogels in industry due to their nanomechanical properties, along with the previously observed temperature-dependent characteristics in graphene-based nanocomposites, a thorough exploration of the thermosensitive nanomechanical properties of GPA is essential. Herein, a comprehensive characterisation of the morphology, composition, and spectroscopic analysis of the GPA for a range of temperatures has been conducted and correlated with its nanomechanical properties. Elevated temperatures have been found to lead to gradual removal of oxygen-containing functional groups (OCFGs) from GPA, resulting in increased structural defects and reduced stiffness. Notably, unique nanomechanical behaviours of GPA have been further identified, where the thermal expansion of sp3 bonds exceeds that of a crystalline sp3 structure, while the thermal contraction of sp2 bonds in GPA is found to be between graphite and GO. This underscores the impact of GO functionalisation on the thermal expansion behaviour of GPA. The obtained insights enhance the overall comprehension of the temperature annealing impact on GPA and highlight the tunability of its nanomechanical properties, showcasing a broad potential of this novel nanocomposite across a diverse range of applications.

The synthesis and characterization of graphene oxide (GO) for water related applications has become an increasing area of research. GO was prepared via Hummer's method, and analysed for structure, morphology, thermal stability, and the ability to remove heavy lead ions from solution. In FTIR analyses, hydroxyl, carboxyl and ester groups were found to be on the structure of GO. XRD showed the interlayer spacing to have increased from graphite to graphene oxide, whereby the average crystallite size of GO was 16.13. Then SEM confirmed the morphology of GO to be exfoliated and wrinkled, with stacked layers. In TGA, EG degraded in a single step, while GO degraded in three distinct steps. When using AAS to analyse the Pb (II) ion intake properties of GO, it showed a maximum adsorption of 98.1% for 600 ppm lead ion solution. The Freundlich isotherm model was consistent with this adsorption, meaning that adsorption took place on a heterogenous surface, on a multilayer basis. The value of n for this isotherm was 0.1474, implying a dominant chemical adsorption. A significant contribution was done to the structure of GO, with its metal adsorption properties clearly portrayed.

Palm oil shows significant potential for development as a lubricant due to its long molecular fatty acid chain, which is capable of minimizing wear and friction. However, in certain conditions, the formation of a thin layer of fluid film may no longer sustain to protect the contact surfaces. Therefore, a relevant additive is needed to address this issue. In this study, trimethylolpropane (TMP) was used as a lubricant, and Graphene Oxide (GO) was employed as the nano-based additive. A Four-ball tribotester was utilized to determine the friction coefficient, wear scar, and surface roughness of the contact surfaces under various operating conditions. The results were compared to mineral and synthetic-based oils. It was found that the combination of TMP and GO exhibited a lower friction coefficient compared to mineral and synthetic-based oils, but slightly higher compared to pure TMP. However, TMP+GO demonstrated significant improvement in terms of wear scar diameter and surface roughness. The physical appearance of the wear was also discussed in this study.

Currently, one of the topical directions in the field of production and application of graphene-like nanostructures is the use of renewable natural raw materials, which have unlimited resources for an economically efficient large-scale yield of a product with environmental safety. In this regard, we present the production of graphene oxide (GO) from a renewable natural raw material of plant biomass, birch activated carbon (BAC), and a comparison of the obtained physicochemical, mechanical, and electrical properties of birch activated carbon–graphene oxide (BAC–GO) and graphite–graphene oxide (G–GO) synthesized from the initial materials, BAC and graphite (G). Results obtained from this study confirm the successful oxidation of BAC, which correlates well with the physical–chemical dates of the G–GO and BAC–GO samples. Change in data after the oxidation of graphite and BAC was facilitated by the structure of the starting materials and, presumably, the location and content of functional oxygen-containing groups in the G–GO and BAC–GO chains. Based on the results, the application of a cost-effective, eco-friendly colloidal solution of nanodispersed BAC–GO from a plant biomass-based high-quality resource for producing large-scale nanostructured graphene is validated which has potential applicability in nanoelectronics, medicine, and other fields.

Integrating hyperthermia with conventional cancer therapies shows promise in improving treatment efficacy while mitigating their side effects. Nanotechnology-based hyperthermia, particularly using superparamagnetic iron oxide nanoparticles (SPIONs), offers a simplified solution for cancer treatment. In this study, we developed composites of SPION quantum dots (Fe3O4) with reduced graphene oxide (Fe3O4/RGO) using the coprecipitation method and investigated their potential application in magnetic hyperthermia. The size of Fe3O4 nanoparticles was controlled within the quantum dot range (≤10 nm) by varying the synthesis parameters, including reaction time as well as the concentration of ammonia and graphene oxide, where their biocompatibility was further improved with the inclusion of polyethylene glycol (PEG). These nanocomposites exhibited low cytotoxic effects on healthy cells (CHO-K1) over an incubation period of 24 h, though the inclusion of PEG enhanced their biocompatibility for longer incubation periods over 48 h. The Fe3O4/RGO composites dispersed in acidic pH buffer (pH 4.66) exhibited considerable heating effects, with the solution temperature increasing by ~10 °C within 5 min of exposure to pulsed magnetic fields, as compared to their dispersions in phosphate buffer and aqueous dimethylsulfoxide solutions. These results demonstrated the feasibility of using quantum dot Fe3O4/RGO composites for magnetic hyperthermia-based therapy to treat cancer, with further studies required to systematically optimize their magnetic properties and evaluate their efficacy for in vitro and in vivo applications.

This review explores the application of graphene-based materials (GBMs) in biomedicine, focusing on graphene oxide (GO) and its interactions with peptides and proteins. GO, a versatile nanomaterial with oxygen-containing functional groups, holds significant potential for biomedical applications but faces challenges related to toxicity and environmental impact. Peptides and proteins can be functionalized on GO surfaces through various methods, including non-covalent interactions such as π–π stacking, electrostatic forces, hydrophobic interactions, hydrogen bonding, and van der Waals forces, as well as covalent bonding through reactions involving amide bond formation, esterification, thiol chemistry, and click chemistry. These approaches enhance GO’s functionality in several key areas: biosensing for sensitive biomarker detection, theranostic imaging that integrates diagnostics and therapy for real-time treatment monitoring, and targeted cancer therapy where GO can deliver drugs directly to tumor sites while being tracked by imaging techniques like MRI and photoacoustic imaging. Additionally, GO-based scaffolds are advancing tissue engineering and aiding tissues’ bone, muscle, and nerve tissue regeneration, while their antimicrobial properties are improving infection-resistant medical devices. Despite its potential, addressing challenges related to stability and scalability is essential to fully harness the benefits of GBMs in healthcare.

Herein, we introduce a simple precipitation method for preparing graphene oxide–silver nanoparticle (GO/AgNP) composites, utilizing Calendula officinalis (C. officinalis) seed extract as both a reducing and stabilizing agent. Our research combines the sustainable preparation of graphene oxide (GO) with the green synthesis of silver nanoparticles (AgNPs), aiming to explore the potential of the obtained composite as a novel antibacterial material. To establish a benchmark, the synthesis was also performed using sodium citrate, a conventional reducing agent. The resultant GO/AgNP composites were characterized through several analytical techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDS), Raman spectroscopy, X-ray diffraction (XRD), infrared (IR) spectroscopy, and ultraviolet–visible (UV-vis) spectroscopy, confirming the successful functionalization of GO with AgNPs. The antibacterial effectiveness of the composites was systematically assessed against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), with nanoparticle concentrations spanning from 0 to 250 µg/mL, utilizing mostly disk diffusion and colony-forming unit (CFU) count assays. The AgNPs were characterized by a size range of 15–50 nm. Notably, the GO/AgNP composite prepared using C. officinalis seed extract demonstrated superior antibacterial activity at all tested concentrations, outperforming both pure GO and the GO/AgNP composite prepared with sodium citrate. The most pronounced antibacterial effect was observed at a concentration of 32.0 µg/mL. Therefore, this innovative synthesis approach may offer a valuable contribution to the development of new therapeutic agents to combat bacterial infections, suggesting further exploration into antibacterial coatings or potential drug development.

Water pollution caused by textile dyes is considered a major and growing issue. To address this challenge, in this research, water-stable Cu-MOFs/GO composite catalysts were produced using the hydrothermal synthesis method as an efficient persulfate (PDS) activator for methyl orange (MO) degradation. We also explored the changes in surface morphology, crystal structure, surface functional groups, and valence states of the materials before and after the introduction of GO by Cu-MOFs. It was shown that Cu-MOFs/GO demonstrates a more stable surface structure, and the unique folded structure of GO provides a better hydrophobic environment for Cu metal cluster hence making MOF easier to grow. The Cu-MOFs/GO-PDS system showed a high activation performance on persulfate in a wide pH range (3–11), meanwhile, was less affected by the presence of natural anions in the environment and more inhibited by natural organic matter citric acid. Furthermore, the Cu-MOFs/GO had excellent stability, reusability and structural integrity, and the removal rate of MO was maintained after five cycles. In terms of oxidation mechanism, in addition to the generation of ·SO4− and OH· radicals, there were also singlet oxygen 1O2 and active Cu(III) in the system, and all of these active substances contributed to the removal of pollutant MO.

In this study, magnetic graphene oxide (MGO-Fe3O4) nanocomposite was prepared by co-precipitating of FeCl3.6H2O and FeCl2.4H2O on waste battery-derived graphene oxide and used as an adsorbent for the efficient removal of As(III) from aqueous solutions. The prepared nanocomposite was characterized by Fourier transformed infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, zeta potential, and a vibrating sample magnetometer. These characterizations revealed that spare like Fe3O4 nanoparticles (10.5 nm) were decorated on graphene oxide nanosheets and showed excellent saturation magnetization (89.73 emu/g). The adsorption of As(III) by MGO-Fe3O4 was optimized by analyzing various parameters. Experiments showed that 98 % of As(III) was removed at neutral pH in a just 20 min, even though the adsorbent dose was only 0.14 g/L. The adsorption kinetic and isotherm were best fitted with the pseudo-second order kinetic and Frendlich isotherm model. The maximum adsorption capacity (qmax) was found to be 50.2 mg/g at room temperature. Thermodynamic studies showed that the As(III) adsorption process was spontaneous and exothermic in nature. The enhanced adsorption capacity and magnetic properties of MGO-Fe3O4 are crucial in the drinking water treatment process due to the easy magnetic separation of MGO-Fe3O4 from aqueous solution after the adsorption process. Density Functional Theory (DFT) was also used to investigate the interaction between MGO-Fe3O4 and As(III), which further suggested that MGO-Fe3O4 and As(III) mostly interact with each other through surface complexation and hydrogen bonding.

The Hall method was used to study the electrical characteristics of composite materials based on polyaniline (PANI), graphene oxide (GO), and manganese. A comparison of these characteristics of GO-PANI and GO-PANI-Mn composite systems with GO and PANI monomaterials was carried out. It was demonstrated that the electrical conductivity of composites was significantly higher than that of monomaterials and was determined by the charge carrier mobility. Based on UV-visible and IR spectroscopy data, it was shown that the optical band gap (Eg) of the GO-PANI composite increased with the addition of metal, but decreased compared to PANI; the shift of characteristic vibrations to lower frequencies indicated a covalent interaction of the GO-PANI composite with manganese cations

Excellent electromagnetic wave absorption ability and effective absorption bandwidth have been the development direction of electromagnetic wave absorbing materials. In this paper, a rational structural design is proposed. Graphene oxide (GO)/polyaniline (PANI) layer was formed on the surface of the natural material bamboo powder (BP) by an interfacial polymerization process. The combination of GO and PANI improves the impedance mismatch of the conductive polymer PANI. Enhanced dielectric storage and loss capability of the composite GO/PANI/BP. The addition of BP brings more electromagnetic wave loss channels to the composite GO/PANI/BP. This unique structure facilitates the construction of a three-dimensional electromagnetic wave-reflecting cavity, which improves the absorptive capacity of the composite by introducing effective multiple reflections. The conductivity of GO/PANI/BP was 1.78 (±0.06) S/cm. When filled to 30 wt%, a minimum reflection loss (RLmin) of −44 dB at 9.36 GHz and a thickness of 3 mm, and an effective absorption bandwidth (

Oxidation of graphite and subsequent exfoliation leads to single layer graphene oxide (GO). One of the key structural features of GO is the presence of different kinds of defects that dictates their various physical and chemical properties. Molecular dynamics simulations with ReaxFF force fields have been widely used to generate realistic models of GO. In these simulations, the extent and distribution of the defects are varied by changing the initial oxygen (O)/carbon (C) ratio while the defect density is often measured by the total number of non-graphitic carbon (non-gC) atoms. Our calculations suggest that this parameter overestimates the defect densities at low O/C ratio. Herein, we employ the relative area of the defects as an alternative metric to gauge the defect density. Being exclusive to the defects and sensitive to the structural irregularities, this metric works well at both low and high defect densities. In another example, we consider the reduction of GO to reduced graphene oxide (rGO) for different O/C ratios, where the decrease in the number of non-gC atoms is associated with the formation of comparatively larger defects. Hence, it is unclear whether the extent of reduction in the defect density (if at all) should vary monotonically with the O/C ratio. The defect area, unlike the count of the non-gC atoms, mirrors this ambiguity and the change with respect to O/C ratio is not strictly monotonic. Additionally, we also investigate the dependence of the defect distribution and defect area on the size of the simulation cell.

In this study, a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method with using a reduced graphene oxide-modified melamine sponge (r-GO@MeS) as matrix purification material was developed for the determination of 35 veterinary drug residues in black chicken meat by ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). First of all, the effects of metal chelating agents (Na2EDTA), dehydrating agents (MgSO4, Na2SO4) and acetic acid (HAc) addition (0%, 0.5%, 1%, 3%, 5%) on the extraction efficiency of veterinary drugs were thoroughly studied. According to the results, most of quinolones tended to chelate with magnesium ions, resulting in low recoveries of veterinary drugs in the extraction solution, while the appropriate addition of Na2EDTA and HAc could improve the overall drug recoveries. Therefore, 2.5 mL of 0.1 mmol/L Na2EDTA aqueous solution and 10 mL of 0.5% HAc-ACN were used as extraction solvents, with 2.0 g of anhydrous Na2SO4 and 0.5 g of NaCl as dehydrating agents. Then the effects of sponge dosages (sponge volume/extract volume of 0.45, 0.60, 0.75, 0.90, 1.05 cm3/mL) and different purification modes (dynamic cycles of 1, 5, 10, static time of 1, 5, 10 min) on the purification efficiency were investigated in terms of veterinary drug recoveries. The results showed that a moderate dosage of 0.75 cm3/mL and fast ten dynamic purification cycles tended to give out more acceptable recoveries for all drugs. The method validation results showed that the recoveries of all monitored drug were obtained in the range of 66.6%-118.8% with three different spiked levels of 50, 100, 150 μg/kg. The intra- and inter-day precisions were evaluated in terms of relative standard deviations (RSDs) by repeatability tests conducted on the same day or three consecutive days, which were acquired less than 13.8% and 14.6%, respectively. In the range of 5-200 μg/kg, good linearities were acquired with the correlation coefficients (R2) no less than 0.998. Additionally, the limits of detection (LODs) and quantitation (LOQs) were obtained in the range of 0.1-6 μg/kg and 0.3-15 μg/kg, respectively. By construction of matrix-matched curves and solvent curves, the matrix effect was calculated as -19.4%-19.8%, demonstrating an insignificant matrix effect by using the developed r-GO@MeS materials. Comparatively, the developed r-GO@MeS has the same or even better matrix purification effect as the other three commercial adsorption materials, such as PSA, GCB, C18. Furthermore, the purification process was achieved within several seconds by the quick and convenient soaking-squeezing cycles, and the matrix separation need no extra measures such as high-speed centrifugation and strong magnetic field assistance. This method has the advantages of speed, convenience and low cost, and shows great potential in the field of multi-residue detection of veterinary drugs.

In this research, the synthesis of L/Fe3O4-methionine and graphene oxide and graphene aerogel nanocomposites (Fe3O4/L-Met/GO, Fe3O4/L-Met, Fe3O4/L-Met/GA) was carried out. Then the structure of the synthesized nanocomposites was confirmed by FT-IR, FE-SEM and BET analyses. Then, the effect of different experimental parameters such as initial pH and contact time on the process of cadmium surface adsorption were investigated. The results showed that the highest percentage of cadmium absorption (90%) occurred at Ph=6 by Fe3O4/L-Met/GA nano adsorbent. Therefore, the cadmium (Cd2+) absorption capacity by Fe3O4/L-Met/GA nanocomposite (212.31 mg/g) is higher than the cadmium (Cd2+) absorption capacity by Fe3O4/L-Met nanocomposites (201.23 mg/g). ) Obtained. Adsorption kinetics data showed excellent fit with pseudo-second-order models (R2>0.99) and Freundlich isotherm models.showed high adsorption capacity towards Cd2+ (212.31 mg/g), which was significantly higher than Fe3O4/L-Met (201.23 mg/g). Finally, adsorption kinetics, isotherm studies were investigated. Absorption data showed excellent fit with quasi-second order models (R2> 0.99) and Freundlich isotherm models.

A novel nanocomposite film synthesized from an inexpensive and easily accessible polymer such as poly (vinyl alcohol) (PVA), which is coated with nickel sulfide (NiS) and graphene oxide (GO), was obtained from used drinking-water bottles. The produced coated film was examined as a potential photocatalyst film for wastewater treatment promotion in a batch system for the removal of methylene blue (MB) and tetracycline (TC) antibiotics. The experimental results show that the presence of GO significantly increases the photocatalytic efficiency of NiS, and the MB and TC degradation results proved that the incorporation of GO with NiS led to a more than one-and-a-half-fold increase in the removal percentage in comparison with the NiS/PVA-coated film. After 30 min of illumination using GO/NiS/PVA-coated film, the removal efficiency reached 86% for MB and 64% for TC. The photodegradation kinetic rate followed the pseudo-first-order rate. Furthermore, the response surface methodology (RSM) model was utilized to study and optimize several operating parameters. The ideal circumstances to achieve 91% elimination of MB are 12 mg L−1 MB initial concentration, two lamps, and an illumination time of 15 min; however, to achieve 85% TC removal, 11 mg L−1 TC initial concentration, two lamps, and a 45 min illumination time should be used. The fabricated nanocomposite photocatalyst film seems to have promise for use in water purification systems.

Non-fluorinated chitosan-based proton exchange membranes (PEMs) have been attracting considerable interest due to their environmental friendliness and relatively low cost. However, low proton conductivity and poor physicochemical properties have limited their application in fuel cells. In this work, a reinforced nanofiller (sulfonated CS/GO, S-CS/GO) is accomplished, for the first time, via a facile amidation and sulfonation reaction. Novel chitosan-based composite PEMs are successfully constructed by the incorporation of the nanofiller into the chitosan matrix. Additionally, the effects of the type and amount of the nanofillers on physicochemical and electrochemical properties are further investigated. It is demonstrated that the chitosan-based composite PEMs incorporating an appropriate amount of the nanofillers (9 wt.%) exhibit good membrane-forming ability, physicochemical properties, improved proton conductivity, and low methanol permeability even under a high temperature and low humidity environment. When the incorporated amounts of S-CS/GO are 9 wt.%, the proton conductivity of the composite PEMs was up to 0.032 S/cm but methanol permeability was decreased to 1.42 × 10−7 cm2/s. Compared to a pristine CS membrane, the tensile strength of the composite membrane is improved by 98% and the methanol permeability is reduced by 51%.

Construction materials are at the forefront of global economic development as they provide the foundation for the infrastructure of other industries, with cementitious materials being predominantly used in construction projects. To promote sustainable development, alternative materials are added to cement mortar to increase durability and reduce emissions. In this regard, graphene oxide (GO) and fly ash (FA) are two alternative materials commonly used in cement mortar, which are readily available or are just the waste from other local material production. With different ratios, the amount of GO and FA can affect the properties of cement mortar positively or negatively. This study aims to determine the effects of GO and FA on cement mortar mixtures under material conditions. Research results show that 10 wt% FA and 0.036 wt% GO will give cement mortar the best physical and mechanical properties while ensuring other necessary properties, such as workability. When increasing FA to 30 wt% or GO to 0.05 wt%, the strength of the mortar mixture tends to decrease. Another issue is that the specific surface area of graphene is very high, which poses a significant challenge when uniform dispersion in the cement paste mixture is required. Polycarboxylate combined with a specific mixing sequence has demonstrated good dispersibility and high stability. Through this research, it is demonstrated that the addition of GO and FA has the potential for sustainable development of the construction industry by considering the contexts of the local recycled cementitious replacement materials.

Graphene and graphene oxide have shown good antibacterial activity against different bacterial species due to their unique physicochemical properties. Graphene oxide (GO) has been widely used to load metallic and metal oxide nanoparticles (NPs) to minimize their surface energy during processing and preparation, hence reducing their aggregation. In this work, GO was effectively synthesized and coated with different concentrations of zinc hydroxide Zn (OH)x using the precipitation method to prepare a GO/Zn (OH)x hybrid composite. The Zn (OH)x NPs and GO/Zn (OH)x nanocomposites were synthesized and characterized using various methods such as scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Coating GO with Zn (OH)x NPs resulted in improved aggregation of Zn (OH)x NPs as well as enhanced antibacterial activity of GO against Gram-positive and Gram-negative bacteria. Additionally, the effect of Zn (OH)x coating on the antibacterial properties of the GO/Zn (OH)x composite was systematically investigated. The synergistic effects of GO and Zn (OH)x NPs resulted in enhanced antibacterial properties of the composites compared to the pristine GO material. In addition, increasing the Zn (OH)x wt. % concentration led to an increased inhibition zone of the GO/Zn (H)x composite against Bacillus megaterium and E. coli bacteria.

Keeping wounds clean in small animals is a big challenge, which is why they often become infected, creating a risk of transmission to animal owners. Therefore, it is crucial to search for new biocompatible materials that have the potential to be used in smart wound dressings with both wound healing and bacteriostatic properties to prevent infection. In our previous work, we obtained innovative hyaluronate matrix-based bionanocomposites containing nanosilver and nanosilver/graphene oxide (Hyal/Ag and Hyal/Ag/GO). This study aimed to thoroughly examine the bacteriostatic properties of foils containing the previously developed bionanocomposites. The bacteriostatic activity was assessed in vitro on 88 Gram-positive (n = 51) and Gram-negative (n = 37) bacteria isolated from wounds of small animals and whose antimicrobial resistance patterns and resistance mechanisms were examined in an earlier study. Here, 69.32% of bacterial growth was inhibited by Hyal/Ag and 81.82% by Hyal/Ag/GO. The bionanocomposites appeared more effective against Gram-negative bacteria (growth inhibition of 75.68% and 89.19% by Hyal/Ag and Hyal/Ag/Go, respectively). The effectiveness of Hyal/Ag/GO against Gram-positive bacteria was also high (inhibition of 80.39% of strains), while Hyal/Ag inhibited the growth of 64.71% of Gram-positive bacteria. The effectiveness of Hyal/Ag and Hyal/Ag/Go varied depending on bacterial genus and species. Proteus (Gram-negative) and Enterococcus (Gram-positive) appeared to be the least susceptible to the bionanocomposites. Hyal/Ag most effectively inhibited the growth of non-pathogenic Gram-positive Sporosarcina luteola and Gram-negative Acinetobacter. Hyal/Ag/GO was most effective against Gram-positive Streptococcus and Gram-negative Moraxella osloensis. The Hyal/Ag/GO bionanocomposites proved to be very promising new antibacterial, biocompatible materials that could be used in the production of bioactive wound dressings.

Many studies on flexible strain and pressure sensors have been reported due to growing interest in wearable devices for healthcare purposes. Here, we present flexible pressure and strain (motion) sensors prepared with only graphene oxide (GO) and commercial silk fabrics and yarns. The pressure sensors were fabricated by simply dipping the silk fabric into GO solution followed by applying a thermal treatment at 400 °C to obtain reduced GO (rGO). The pressure sensors were made from rGO-coated fabrics, which were stacked in three, five, and seven layers. A super-sensitivity of 2.58 × 103 kPa−1 at low pressure was observed in the seven-layer pressure sensor. The strain sensors were obtained from rGO-coated twisted silk yarns whose gauge factor was 0.307. Although this value is small or comparable to the values for other sensors, it is appropriate for motion sensing. The results of this study show a cost-effective and simple method for the fabrication of pressure and motion sensors with commercial silk and GO.

In this paper, the oxidation–exfoliation process of graphite is studied experimentally by the mixed-solvent method, the oxidation–exfoliation process of graphite is simulated theoretically, and it is found that Graphene Oxide (GO) is a Janus structure with inconsistent oxidation on both surfaces; hydrophilic on one side and hydrophobic on the other side. This layer structure and layer spacing are due to the inconsistent oxidation on both sides which changes with the polarity of different solvent mixtures. We used a two-phase system of benzyl alcohol and water, as well as controlling the polarity of the surface of the substrate, to achieve (using a mixed solution of GO which has a selectivity more inclined to the oil phase when the aqueous phase is present) the preparation of reduced graphene oxide patterns. We also used a complex solution of hydrogen iodide and a sodium–iodide complex solution for secondary reduction to enhance its conductivity to 8653 S/m.

Abstract With the development of society, pollution accidents occur more frequently, and the effects of toxic substances containing silver on human health and environment are increasingly extensive. Therefore, the real-time on-site monitoring of silver ions is urgently needed. Based on the catalase-like properties of graphene/nano-platinum composites and the coupling effect between Pt and Ag+, a simple, unlabeled colorimetric sensing method is proposed to achieve the quantitative detection of Ag+. Under optimal conditions, the detection range of Ag+ by this colorimetric sensing method is 0.5–1000 μM, and the detection limit is 0.5 μM, which is lower than the previously reported detection limit of unlabeled Ag+ colorimetric sensing method, showing higher sensitivity and detection range. Under the same conditions, the sensor has almost no response to interference ions, showing good specific recognition ability. In addition, the colorimetric sensing method can be used to detect Ag+ in actual water samples, serving as a new paradigm for visual detection of Ag+. Graphical abstract

A green biosynthesis of silver nanoparticles (AgNPs) decorated Mentha longifolia root extract-functionalized graphene oxide (GO) nanohybrid material has been described. Initially, the Mentha longifolia root was coated on GO’s surface. The phytochemicals of the plant acted as reducing agent for reduction of silver ions and GO to form the rGO-Mentha/Ag nanocomposite. The nanocomposite was characterized using FE-SEM, EDX, FT-IR, TEM, elemental mapping, and XRD analysis. The cells treated with rGO-Mentha/Ag nanocomposite were assessed by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay for 48 h about the cytotoxicity and anti-human ovarian cancer properties on normal (HUVEC) and human ovarian cancer cell lines, i.e., SKOV3 and A2780. The IC50 of rGO-Mentha/Ag nanocomposite were 181.2 and 196.4 µg/mL against SKOV3 and A2780cell lines, respectively. The viability of malignant human ovarian cell line reduced dose-dependently in the presence of rGO-Mentha/Ag nanocomposite. After clinical study, rGO-Mentha/Ag nanocomposite can be introduced as a novel composite in the treatment of human ovarian cancer.

Detecting and characterizing coffee aroma is crucial for determining the quality of coffee. While gas chromatography is the standard method, using gas sensors is a feasible alternative. The electrode material used extensively influences the response produced by the gas sensor. This study explores using composites of the conductive polymer polypyrrole (PPy) and graphene oxide (GO) as materials for gas sensor electrodes. In the study, we synthesized PPy and GO and characterized them using UV-Vis and FTIR spectrophotometry, confirming that the compounds obtained were PPy and GO. The researchers varied the composition and thickness of PPy/GO in electrode fabrication. Varying the percentage of GO in the composite by 0, 5, 10, and 15% GO resulted in different PPy/GO compositions, while electrode thicknesses observed were 0.083, 0.21, 0.39, and 60 mm. Electrode characterization, including sensitivity, conductivity, and response time, showed that the PPy/GO electrode with a composition of 15% GO and a thickness of 0.21 mm had the best response. The PPy/GO sensor was tested on the aroma of Robusta coffee from three different plantations in the Jember area, East Java. It was able to distinguish the aroma of coffee. Measurement of electrode reproducibility in measuring each sample for one month showed consistent results from week to week, with a %RSD of less than 5%. The research results demonstrate that the PPy/GO sensor with a GO composition of 15% and a thickness of 0.21 mm has excellent potential for differentiating the aroma of coffee with different compositions of constituent compounds.

In this research, graphene oxide (GO) was functionalized with D-penicillamine (DPA) and used to develop an electrochemical sensor for Cu(II) cation. For the successful synthesis of D-penicillamine-functionalized graphene oxide (DPA-GO), Fourier Transfer Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), X-ray diffraction pattern (XRD), and Transmission Electron Microscopy (TEM) are used. DPA-GO modified glassy carbon electrode (DPA-GO / GCE) was prepared and its electrochemical behavior was studied in the presence of Cu(II) cations by cyclic voltammetry, and the results showed the better performance of the DPA-GO-modified electrode compared to unmodified and GO-modified electrode, which related to GO nanostructure and complexing ability of sulfur, nitrogen, and oxygen-containing functional groups in the DPA structure. The prepared sensor was used for the selective and sensitive measurement of Cu(II) cations by square-wave anodic stripping voltammetry (SW-ASV) and the factors affecting the sensor performance were investigated and optimum conditions for sensor operation were determined. Under the optimal conditions, the prepared electrode has a linear response in the range of 1 pM to 0.1 µM and its detection limit was 0.31 pM. The proposed sensor was used satisfactorily to measure copper cation in real water samples with suitable reproducibility and stability.

Since the advent of nanoscience, nanobiomaterials have been applied in the dental industry. Graphene and its derivatives have attracted the most interest of all of them due to their exceptional look, biocompatibility, multiplication differential, and antibacterial capabilities. We outlined the most recent developments about their applications to dentistry in our review. There is discussion of the synthesis processes, architectures, and characteristics of materials based on graphene. The implications of graphene and its counterparts are then meticulously gathered and described. Finally, in an effort to inspire more excellent research, this paper explores the obstacles and potential of graphene-based nanomaterials for dental aspects.

This study explores the synthesis and characterization of a novel double cross-linked hydrogel composed of polyvinyl alcohol (PVA), sodium alginate (SA), graphene oxide (GO), and glutathione (GSH), henceforth referred to as PVA/SA/GO/GSH. This innovative hydrogel system incorporates two distinct types of cross-linking networks and is meticulously engineered to exhibit sensitivity to high glucose and/or reactive oxygen species (ROS) environments. A sequential approach was adopted in the hydrogel formation. The initial phase involved the absorption of GSH onto GO, which was subsequently functionalized with boric acid and polyethylene glycol derivatives via a bio-orthogonal click reaction. This stage constituted the formation of the first chemically cross-linked network. Subsequently, freeze-thaw cycles were utilized to induce a secondary cross-linking process involving PVA and SA, thereby forming the second physically cross-linked network. The resultant PVA/SA/GO/GSH hydrogel retained the advantageous hydrogel properties such as superior water retention capacity and elasticity, and additionally exhibited the ability to responsively release GSH under changes in glucose concentration and/or ROS levels. This feature finds particular relevance in the therapeutic management of diabetic ulcers. Preliminary in vitro evaluation affirmed the hydrogel’s biocompatibility and its potential to promote cell migration, inhibit apoptosis, and exhibit antibacterial properties. Further in vivo studies demonstrated that the PVA/SA/GO/GSH hydrogel could facilitate the healing of diabetic ulcer sites by mitigating oxidative stress and regulating glucose levels. Thus, the developed PVA/SA/GO/GSH hydrogel emerges as a promising candidate for diabetic ulcer treatment, owing to its specific bio-responsive traits and therapeutic efficacy.

Monitoring and control of humidity is important for industry, agriculture and human activities. Currently, it is achallengeto develop highly sensitive humidity sensors with both the response time and recovery time less than 1 s.Therefore, it isdifficult to dynamically monitor rapid changes in humidity. Here, we report a resistive humidity sensor based on an ultrathin graphene oxide (GO) film, which is formed by stacked single-layered GO. Both the response and recovery time of the sensor is less than 1 s in the range of 10 %–95 % relative humidity (RH). The shortest response and recovery time of the reported GO-based resistive humidity sensor can be 0.33 s at 10 % RH, indicating the fastest response and recovery property to date. Moreover, the sensor is sensitive, and it can accurately detect the distance between the sensor and the human finger as well as the strength of the human breath. The simple preparation, microscale structure, and extremely fast response make the GO-based sensor a new alternative for integrated humidity sensors with real-time monitoring functions.

The determination of bioactive compounds in food samples has received significant attention in recent years due to their potential health benefits. Epicatechin (EC) is one of the flavanol compounds naturally present in various foods such as tea, cocoa, grapes, and berries. It has various potential health benefits, including antioxidant, anti-inflammatory, and anti-cancer properties. However, excessive intake of EC can also have negative effects on health. The accurate and reliable detection of EC in food samples is crucial for ensuring consumer safety and maintaining quality control standards in the food industry. Therefore, developing a sensitive and reliable sensor for detecting EC in food samples is of significant importance. This research presents a novel method for detecting EC in various food samples. The method involves the use of a nickel-oxide/cobalt-oxide/reduced-graphene-oxide composite material (NiO/CoO/rGO) synthesized through a microwave-assisted technique which is then applied to a glassy carbon electrode to fabricate NiO/CoO/rGO/GCE sensor for sensitive determination of EC. The structural, morphological, and electrochemical characteristics of the electrode materials were analyzed using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) spectroscopy, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The morphological results confirmed the formation of well-dispersed NiO/CoO nanoparticles on the surface of rGO sheets. The electrochemical results revealed that the NiO/CoO/rGO/GCE sensor has exceptional electron-transport properties and electrocatalytic activity towards EC, with an Rct value of 90.85 kΩ that is lower than that of the Bare/GCE and GO/GCE electrodes, which attributed to the synergistic effect of NiO/CoO nanoparticles and rGO sheets. The method was found to have a detection limit of 0.0012 μM for EC, with a linear range of 0.05–65 μM. The sensor was also reliable, stable, reproducible, and selective, and yielded excellent recoveries (near to 100 %) with low RSD values for detecting EC in food samples.

A 3D framework was effectively created by cross-linking graphene oxide nanosheets with 2,5-bis(((3-mercaptopropyl)dimethoxysilyl)oxy)terephthalohydrazide as a sulfur-containing linker, resulting in a successful synthesis of a novel chelating adsorbent. The resulting material showed remarkable efficiency in removing Hg2+ ions from polluted water, with a high adsorption capacity of 204.08 mg g−1 at pH 6 and 25 °C. The adsorption process followed a monolayer model described by the Langmuir isotherm, and the kinetics followed a pseudo-second-order model, indicating a chemical adsorption mechanism. The material demonstrated rapid adsorption and desorption, maintaining its performance even after multiple regeneration cycles. Overall, the synthesized 3D GOF stands out as an exceptional adsorbent due to its porous structure, efficient chelating functional groups, and robust efficacy in eliminating Hg2+ ions from contaminated water sources.

Lung cancer is one of the most common diseases worldwide today and has the highest mortality rate among cancers. Therefore, early diagnosis of this disease is of special importance. Due to the fact that common methods for detecting lung cancer are costly and time-consuming, providing cheaper and faster methods has received special attention. With the significant development of nanotechnology in recent years and the development of various nanomaterials, activities have been carried out in this field. Recent studies show that graphene oxide nanomaterials, due to their unique properties, have a high potential in the design of biosensors to detect lung cancer.

Advanced oxidation (AOPs) utilizing peroxymonosulfate (PMS) are efficient processes for the degradation of organic pollutants. This study aimed to synthesize and characterize cobalt ferrite (CoFe2O4), graphene oxide (GO), MIL-101(Fe), and their composite structures. The nanomaterials were applied as catalysts by PMS for triclosan (TCS) decomposition. The maximum removal rates of TCS were 49.29, 66.13, 84.04, 89.73, and 100% for PMS alone, CoFe2O4, GO, MIL-101(Fe), and CoFe2O4/MIL-101(Fe)/GO with PMS, respectively. Metal ions leaching declined in CoFe2O4/MIL-101(Fe)/GO/PMS compared with others. Hence, the composite nanomaterials appear to be effective catalysts for the degradation of organic pollutants by PMS activation.

Antimicrobial AgO/Ag/carboxymethyl chitosan-graphene oxide (AgO/Ag/CGO) films were synthesized by UV-light-assisted reduction followed by ionic crosslinking method. The structure of the AgO/Ag/CGO films were explored by X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), ultraviolet–visible spectroscopy (UV–vis), and Fourier-transform infrared (FTIR) analysis. We have also tested the cytotoxicity and cell viability of AgO/Ag/CGO3. The results of cytotoxicity of AgO/Ag/CGO3 on HepG2 cells suggests that the nanocomposite is not cytotoxic. Additionally, thermal stability, swelling ratio, antimicrobial activity of the AgO/Ag/CGO films were evaluated in detail, which revealed that the addition of GO improves the thermal stability and swelling ratio of AgO/Ag/CGO films. Of the three AgO/Ag/CGO films, the AgO/Ag/CGO3 exhibited better antimicrobial activity and higher inhibition rate against E. coli (89.2%) and S. aureus (93.4%). Therefore, the simple and green method is potential candidate for prepare of Ag-based antimicrobial film materials.