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Introduction: Doxorubicin (DOX) is one of the most common drugs in cancer treatment. However, its partial solubility along with the high incidence of side effects remains a challenge to tackle. To address these issues, we designed a formulation based on graphene oxide (GO) and used it as an anticancer drug delivery system. Methods: The physical and chemical properties of the formulation were studied using FTIR, SEM, EDX, Mapping, and XRD. Release studies in the in vitro condition were used to evaluate the pH sensitivity of drug release from nanocarriers. Other in vitro studies, including uptake assay, MTT, and apoptosis assay were carried out on the osteosarcoma cell line. Results: In vitro release studies confirmed that the synthesized formulation provides a better payload release profile in acidic conditions, which is usually the case in the tumor site. On the OS cell line, the cytotoxicity of the DOX-loaded nanocarrier (IC50=0.293 μg/mL) and early apoptosis rate (33.80 % ) were higher in comparison to free DOX (IC50=0.472 μg/mL, and early apoptosis rate= 8.31 % ) after 48 hours. Conclusion: In summary, our results suggest a DOX-loaded graphene oxide carrier as a potential platform for targeting cancer cells.

Introduction: Doxorubicin (DOX) is one of the most common drugs in cancer treatment. However, its partial solubility along with the high incidence of side effects remains a challenge to tackle. To address these issues, we designed a formulation based on graphene oxide (GO) and used it as an anticancer drug delivery system. Methods: The physical and chemical properties of the formulation were studied using FTIR, SEM, EDX, Mapping, and XRD. Release studies in the in vitro condition were used to evaluate the pH sensitivity of drug release from nanocarriers. Other in vitro studies, including uptake assay, MTT, and apoptosis assay were carried out on the osteosarcoma (cell line. Results: In vitro release studies confirmed that the synthesized formulation provides a better payload release profile in acidic conditions, which is usually the case in the tumor site. On the OS cell line, the cytotoxicity of the DOX-loaded nanocarrier (IC50=0.293 µg/mL) and early apoptosis rate (33.80 % ) were higher in comparison to free DOX (IC50=0.472 µg/mL, and early apoptosis rate= 8.31 % ) after 48 hours. Conclusion: In summary, our results suggest a DOX-loaded graphene oxide carrier as a potential platform for targeting cancer cells. [ABSTRACT FROM AUTHOR]

Increasing the number of depleted reservoirs and global demand for energy have left us with low alternative but to use new ways to extract more hydrocarbon. Amongst different material used for tertiary oil recovery, surfactant injection has proved very promising solutions, such as interfacial tension reduction and wettability alteration. Without any harm to the environment and meanwhile being economically feasible, natural surfactants have been attracted researchers in recent years. Cedr extraction which is produced from Zizyphus Spina Christi leaves has shown some beneficial characteristics like IFT reduction and wettability alteration. However, the amount of IFT reduction is not considerable, so we decided to augment its effectiveness by adding two different nanoparticles. In this investigation, three concentrations (0.01, 0.05 and 0.1 wt%) of both graphene oxide (GO) nanosheet and GO/TiO2 nanocomposite was added to Cedr extraction solution to study their potential on IFT reduction and improving the ultimate oil recovery. The concentration of 0.05 wt percent showed the lowest IFT in both solutions. At this concentration, the IFT of GO/TiO2-augmented solution and GO-augmented solution were measured of 10.5 and 12.3 mN/m, respectively. While the bare Cedr solution showed 23.8 mN/m at its critical micelle concentration. The coreflooding tests were also performed at the aforementioned concentrations. Final oil recovery reached to 65% of original oil volume in GO/TiO2-augmented solution, compared to 56% in GO-augmented solution case and 40% in bare Cedr solution case. Scanning Electron Microscopy images were also taken from the rock samples exposed to nanofluids to investigate any severe harm to the permeability. Images showed low tendency of both particles to adsorb on rock surface and plug large pores.

In this study, the shrinkage and creep of concrete containing graphene oxide (GO) nanosheets were experimentally and theoretically investigated. Experiments for the shrinkage and creep of concrete with 0.02% and 0.08% GO nanosheets by the weight of cement and common concrete were carried out. Subsequently, the influence of GO nanosheets on the shrinkage and creep of concrete was analyzed and discussed. A modified model was developed to accurately predict the shrinkage and creep of concrete containing GO nanosheets after models for predicting shrinkage and creep of common concrete were compared and the influential factors and application scope were determined. Results indicate that: (1) GO nanosheets can increase the shrinkage strain and reduce the creep coefficient of concrete, and (2) a modified ACI209 (92) model can accurately predict the shrinkage and creep of concrete containing GO nanosheets. Factors considering concrete strength can be introduced in the model to improve the model accuracy.

In this study, removal efficiency and mechanism of four typical ARGs with two different molecular structures (i.e., cyclic (c)- and double-stranded (ds)-ARGs) by graphene oxide (GO) nanosheet were systematically investigated. The average removal of four ARGs was as high as 3.11 logs toward c-ARGs and 2.88 logs toward ds-ARGs at 300 μg/mL GO solution. The data of adsorption were fitted well with Freundlich isotherm and pseudo-second-order kinetic model. The apparent adsorption equilibrium can be obtained within 15 mins for both c-ARGs and ds-ARGs, indicating the effective removal by GO. The free-energy parameters demonstrated that the removal processes were exothermic and spontaneous. The structural differences of genetic molecular structures can be responsible for the removal discrepancy. Moreover, several removal factors containing initial ARGs concentration, pH and ion species were also investigated. The results of Raman spectra, Diffuse Reflectance Infrared Fourier Transform spectroscopy (DRIFTs) and electrochemical analysis indicated that the adsorption of ARGs by GO was mainly attributed to the oxygen containing groups and π-bonding system of GO nanosheet, which resulted in chemical binding with aromatic nucleic acid and strongly π-stacking interactions. Furthermore, a detailed verification test of real water samples was conducted and 80% of the ARGs can be removed from a natural water sample. As a result, it would be great potential to apply GO nanosheet as a novel adsorbent for effective treatment of ARG-contaminated waters. [ABSTRACT FROM AUTHOR]

Sulfonated poly(ether ether ketone) (SPEEK)-based hybrid membranes (S/GO-VIPS) have been fabricated by the solution blending method, which amphoteric GO-VIPS nanofillers prepared by grafting 3-(1-vinyl-3-imidazole) propane sulfonate (VIPS) onto graphene oxide (GO) flake. With various GO-VIPS contents changing from 1 to 10 wt% in the S/GO-VIPS membranes, the interfacial interaction between SPEEK and GO-VIPS contributes to enhanced membrane structures and performance. Against pristine SPEEK (3.9 × 103 S min cm−3) and Nafion 117 (4.0 × 103 S min cm−3), S/GO-VIPS-5 gives the highest ion selectivity at 24.4 × 103 S min cm−3, demonstrating the amphoteric GO-VIPS nanosheets afford a superior vanadium ion resistance and proton conductivity. At 100–200 mA cm−2 current density, S/GO-VIPS-5 presents excellent coulombic efficiency (97.4–99%), energy efficiency (78.9–66.3%), and self-discharge time (78 h), which is better than that of SPEEK and Nafion 117, respectively. Further cycling at 100 mA cm−2 for 350 times, its energy efficiency maintains at 80%, confirming its excellent structural stability and chemical stability. Combining with the physical barrier and the amphoteric acid-base functional groups of the GO-VIPS nanosheets, the increased proton conductivity and ion selectivity, and the decreased permeability of SPEEK-based membranes are well-regulated, demonstrating a promise in developing high-performance proton exchange membrane for vanadium flow battery applications. The formed acid-base interaction and Donnan effect from GO-VIPS nanofillers provide stable energy efficiency and durability of S/GO-VIPS, demonstrating the trade-off of conductivity and permeability is of importance to construct the proton transportation channel and offer the structure stability. [Display omitted] • Amphoteric GO-VIPS nanofillers stabilize proton transportation channel. • Acid-base interaction and Donnan effect afford ultrahigh conductivity. • S/GO-VIPS-5 gives outstanding cell efficiency and charge capacity retention. • Excellent structure stability and durability at 350 cycles. • A promising method to develop high-performance SPEEK-based membranes. [ABSTRACT FROM AUTHOR]

In this study, the shrinkage and creep of concrete containing graphene oxide (GO) nanosheets were experimentally and theoretically investigated. Experiments for the shrinkage and creep of concrete with 0.02% and 0.08% GO nanosheets by the weight of cement and common concrete were carried out. Subsequently, the influence of GO nanosheets on the shrinkage and creep of concrete was analyzed and discussed. A modified model was developed to accurately predict the shrinkage and creep of concrete containing GO nanosheets after models for predicting shrinkage and creep of common concrete were compared and the influential factors and application scope were determined. Results indicate that: (1) GO nanosheets can increase the shrinkage strain and reduce the creep coefficient of concrete, and (2) a modified ACI209 (92) model can accurately predict the shrinkage and creep of concrete containing GO nanosheets. Factors considering concrete strength can be introduced in the model to improve the model accuracy. [ABSTRACT FROM AUTHOR]