Displaying publications 101 - 120 of 357 in total

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  1. Fulltext Effects of Accelerated Weathering on Degradation Behavior of Basalt Fiber Reinforced Polymer Nanocomposites
    Hashim UR, Jumahat A, Jawaid M, Dungani R, Alamery S
    Polymers (Basel), 2020 Nov 06;12(11).
    PMID: 33172162 DOI: 10.3390/polym12112621
    This work aims to give insight on the effect of accelerated weathering, i.e., the combination of ultraviolet (UV) exposure and water spraying, on the visual and mechanical properties of basalt fiber reinforced polymer (BFRP) composites. The solvent exchange method, sonication and high shear milling technique were used to prepare the nanocomposite laminates. Three types of laminates were fabricated, i.e., unmodified BFRP, nanosilica modified BFRP and graphene nanoplatelet (GNP) modified BFRP composites with the total fiber loading of 45 wt.%. Glass fiber reinforced polymer (GFRP) laminate was also prepared for performance comparison purposes between the natural and synthetic fibers. The laminates were exposed to UV with a total weathering condition of 504 h using a Quantum-UV accelerated weathering tester. The weathering condition cycle was set at 8 h 60 °C UV exposure and 4 h 50 °C condensation. The discoloration visual inspection on the tested specimen was observed under the optical microscope. The obtained results showed that the UV exposure and water absorption caused severe discoloration of the laminates due to photo-oxidation reaction. The effect of weathering conditions on tensile and flexural properties of unmodified BFRP composites indicated that the UV exposure and water absorption caused reduction by 12% in tensile strength and by 7% in flexural strength. It is also found that the reduction in tensile and flexural properties of nanomodified BFRP composites was smaller than the unmodified system. It concluded from this work, that the mineral based composites (i.e., BFRP) has high potential for structural applications owing to its better properties than synthetic based composites (i.e., GFRP).
    Matched MeSH terms: Graphite
  2. New effective 3-aminopropyltrimethoxysilane functionalized magnetic sporopollenin-based silica coated graphene oxide adsorbent for removal of Pb(II) from aqueous environment
    Hassan AM, Wan Ibrahim WA, Bakar MB, Sanagi MM, Sutirman ZA, Nodeh HR, et al.
    J Environ Manage, 2020 Jan 01;253:109658.
    PMID: 31666209 DOI: 10.1016/j.jenvman.2019.109658
    A new effective adsorbent, 3-aminopropyltrimethoxysilane functionalized magnetic sporopollenin (MSp@SiO2NH2) based silica-coated graphene oxide (GO), (GO@SiO2-MSp@SiO2NH2) was successfully synthesized and applied for the first time in the removal of hazardous Pb(II) ions from aqueous solution. The properties of the composite were characterized using Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX) and vibrating-sample magnetometery (VSM). Evaluation of GO@SiO2-MSp@SiO2NH2 adsorption performance at optimum conditions revealed that the adsorbent has a maximum adsorption capacity of 323.5 mg/g for Pb(II) using 50-200 mg/L initial Pb(II) ions concentrations. Initial and final concentrations of Pb(II) ions in aqueous solution were analyzed using graphite furnace atomic absorption spectroscopy (GF-ASS). The adsorption behavior of Pb(II) ions onto GO@SiO2-MSp@SiO2NH2 was studied using Langmuir, Freundlich and Temkin isotherms models. The values of coefficient of determination showed that the adsorption best fitted the Langmuir model (R2 = 0.9994). Kinetic studies suggested that the adsorption of Pb(II) ion followed a pseudo-second-order rate model (R2 = 1.00) and thermodynamic studies revealed that the adsorption process is endothermic and spontaneous. The effect of co-existing ions on Pb(II) ion adsorption were also studied and found to have considerable effects only at higher matrix concentration. The adsorbent can be reused up to ten times and retain its good adsorption capacity. In addition, GO@SiO2-MSp@SiO2NH2 showed great potential for Pb(II)removal from industrial wastewater samples.
    Matched MeSH terms: Graphite*
  3. Hierarchically structured ternary heterojunctions based on Ce3+/ Ce4+ modified Fe3O4 nanoparticles anchored onto graphene oxide sheets as magnetic visible-light-active photocatalysts for decontamination of oxytetracycline
    Hassandoost R, Pouran SR, Khataee A, Orooji Y, Joo SW
    J Hazard Mater, 2019 08 15;376:200-211.
    PMID: 31128399 DOI: 10.1016/j.jhazmat.2019.05.035
    The main prerequisite of an active visible-light-driven photocatalyst is to effectively utilize the visible light to induce electron-hole (e-/h+) pairs of expanded lifetime. To this end, for the first time, the ternary heterojunctions of CeO2/Fe3O4 /Graphene oxide and Ce3+/ Fe3O4 /Graphene oxide (CeO2/Fe3O4/GO and Fe2.8Ce0.2O4/GO) were prepared via facile ultrasonic-assisted procedures and employed for destruction of oxytetracycline (OTC) under visible light irradiation. The changes in the relative crystal structure, morphology, atomic and surface functional group composition, magnetic, and optic properties of magnetite were uncovered by various techniques. The substantial degradation and mineralization of OTC via visible light/Fe2.8Ce0.2O4/GO system were thoroughly discussed in terms of narrowed band gap energy, the principal function of Ce3+/Ce4+ and Fe2+/Fe3+ redox pairs and GO platelets, enhanced charge separation and transfer, and enlarged active surface area. Furthermore, the performance of visible light/Fe2.8Ce0.2O4/GO system was evaluated for treating real wastewater and its efficiency was investigated using a number of enhancers and scavengers. Finally, the generated byproducts in the course of photodegradation were determined and the oxidation pathway, photocatalytic kinetics, and plausible mechanism were proposed. The results confirmed that the introduced Ce ions and graphene oxide sheets boost the photo-catalytic efficiency of magnetite for photodegradation of OTC.
    Matched MeSH terms: Graphite/chemistry*
  4. The application of graphene/h-BN metamaterial in medical linear accelerators for reducing neutron leakage in the treatment room
    Hassanpour M, Hassanpour M, Rezaie M, Khezripour S, Faruque MRI, Khandaker MU
    Phys Eng Sci Med, 2023 Sep;46(3):1023-1032.
    PMID: 37219796 DOI: 10.1007/s13246-023-01269-w
    Neutrons can be generated in medical linear accelerators (Linac) due to the interaction of high-energy photons (> 10 MeV) with the components of the accelerator head. The generated photoneutrons may penetrate the treatment room if a suitable neutron shield is not used. This causes a biological risk to the patient and occupational workers. The use of appropriate materials in the barriers surrounding the bunker may be effective in preventing the transmission of neutrons from the treatment room to the outside. In addition, neutrons are present in the treatment room due to leakage in the Linac's head. This study aims to reduce the transmission of neutrons from the treatment room by using graphene/hexagonal boron nitride (h-BN) metamaterial as a neutron shielding material. MCNPX code was used to model three layers of graphene/h-BN metamaterial around the target and other components of the linac, and to investigate its effect on the photon spectrum and photoneutrons. Results indicate that the first layer of a graphene/h-BN metamaterial shield around the target improves photon spectrum quality at low energies, whereas the second and third layers have no significant effect. Regarding neutrons, three layers of the metamaterial results in a 50% reduction in the number of neutrons in the air within the treatment room.
    Matched MeSH terms: Graphite*
  5. Au/Pd@rGO nanocomposite decorated with poly (L-Cysteine) as a probe for simultaneous sensitive electrochemical determination of anticancer drugs, Ifosfamide and Etoposide
    Hatamluyi B, Lorestani F, Es'haghi Z
    Biosens Bioelectron, 2018 Nov 30;120:22-29.
    PMID: 30144642 DOI: 10.1016/j.bios.2018.08.008
    The simultaneous measurement of the concentration of anticancer drugs with a fast, sensitive and accurate method in biological samples is a challenge for better monitoring of drug therapy and better determine the pharmacokinetics. An electrochemical sensor was developed for the simultaneous determination of anticancer drugs, Ifosfamide (IFO) and Etoposide (ETO) based on pencil graphite electrode modified with Au/Pd@rGO nanocomposite decorated with poly (L-Cysteine). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were utilized to study the properties of the modified electrode. The electrochemical behavior of IFO and ETO on the Au/Pd@rGO@p(L-Cys) modified electrode was investigated by cyclic voltammetry and differential pulse voltammetry (DPV) techniques and the obtained results confirmed its efficiency for the individual and simultaneous sensing of IFO and ETO. After optimization of electrochemical parameters, the fabricated sensor presented excellent performance in simultaneous determination of IFO and ETO with a wide linear range from 0.10 to 90.0 μM and 0.01 to 40.0 μM and low detection limits (3 Sb/m) of 9.210 nM and 0.718 nM, respectively. In addition, this study proved that the constructed sensor could be useful to simultaneous analysis of IFO and ETO in biological samples and pharmaceutical compounds.
    Matched MeSH terms: Graphite/chemistry
  6. Fulltext Deformation Properties of Rubberized ECC Incorporating Nano Graphene Using Response Surface Methodology
    Hau Hong DL, Mohammed BS, Al-Fakih A, Wahab MMA, Liew MS, Amran YHM
    Materials (Basel), 2020 Jun 24;13(12).
    PMID: 32599798 DOI: 10.3390/ma13122831
    Engineered cementitious composite (ECC) was discovered as a new substitute of conventional concrete as it provides better results in terms of tensile strain, reaching beyond 3%. From then, more studies were done to partially replace crumb rubber with sand to achieve a more sustainable and eco-friendlier composite from the original ECC. However, the elastic modulus of ECC was noticeably degraded. This could bring potential unseen dangerous consequences as the fatigue might happen at any time without any sign. The replacement of crumb rubber was then found to not only bring a more sustainable and eco-friendlier result but also increase the ductility and the durability of the composite, with lighter specific gravity compared to conventional concrete. This study investigated the effects of crumb rubber (CR) and graphene oxide (GO) toward the deformable properties of rubberized ECC, including the compressive strength, elastic modulus, Poisson's ratio, and drying shrinkage. Central composite design (CCD) was utilized to provide 13 reasonable trial mixtures with the ranging level of CR replacement from 0-30% and that of GO from 0.01-0.08%. The results show that GO increased the strength of the developed GO-RECC. It was also found that the addition of CR and GO to ECC brought a notable improvement in mechanical and deformable properties. The predicted model that was developed using response surface methodology (RSM) shows that the variables (compression strength, elastic modulus, Poisson's ratio, and drying shrinkage) rely on the independent (CR and GO) variables and are highly correlated.
    Matched MeSH terms: Graphite
  7. Adsorptive decontamination of diclofenac by three-dimensional graphene-based adsorbent: Response surface methodology, adsorption equilibrium, kinetic and thermodynamic studies
    Hiew BYZ, Lee LY, Lai KC, Gan S, Thangalazhy-Gopakumar S, Pan GT, et al.
    Environ Res, 2019 01;168:241-253.
    PMID: 30321737 DOI: 10.1016/j.envres.2018.09.030
    Pharmaceutical residues are emerging pollutants in the aquatic environment and their removal by conventional wastewater treatment methods has proven to be ineffective. This research aimed to develop a three-dimensional reduced graphene oxide aerogel (rGOA) for the removal of diclofenac in aqueous solution. The preparation of rGOA involved facile self-assembly of graphene oxide under a reductive environment of L-ascorbic acid. Characterisation of rGOA was performed by Fourier transform infrared, scanning electron microscope, transmission electron microscopy, nitrogen adsorption-desorption, Raman spectroscopy and X-ray diffraction. The developed rGOA had a measured density of 20.39 ± 5.28 mg/cm3, specific surface area of 132.19 m2/g, cumulative pore volume of 0.5388 cm3/g and point of zero charge of 6.3. A study on the simultaneous interactions of independent factors by response surface methodology suggested dosage and initial concentration as the dominant parameters influencing the adsorption of diclofenac. The highest diclofenac adsorption capacity (596.71 mg/g) was achieved at the optimum conditions of 0.25 g/L dosage, 325 mg/L initial concentration, 200 rpm shaking speed and 30 °C temperature. The adsorption equilibrium data were best fitted to the Freundlich model with correlation coefficient (R2) varying from 0.9500 to 0.9802. The adsorption kinetic data were best correlated to the pseudo-first-order model with R2 ranging from 0.8467 to 0.9621. Thermodynamic analysis showed that the process was spontaneous (∆G = - 7.19 to - 0.48 kJ/mol) and exothermic (∆H = - 12.82 to - 2.17 kJ/mol). This research concluded that rGOA is a very promising adsorbent for the remediation of water polluted by diclofenac.
    Matched MeSH terms: Graphite/chemistry*
  8. Differential gene expression of Wharton's jelly-derived mesenchymal cells mediated by graphene oxide in basal and osteo-induced media
    Hiew VV, Teoh PL
    Mol Biol Rep, 2024 Mar 03;51(1):383.
    PMID: 38433142 DOI: 10.1007/s11033-024-09324-9
    BACKGROUND: Graphene oxide (GO) is widespread in scaffold engineering owing to its extraordinary properties such as multiple oxygen functional groups, high hydrophilicity ability and biocompatibility. It is known to promote differentiation in mesenchymal stem cells, but concomitant comparison of its modulation on the expression profiles of Wharton's jelly (WJ)-MSC surface markers, lineage differentiation, and epigenetic regulatory genes in basal and induced condition are still lacking. Unraveling the fundamental mechanisms is essential for the effective utilization of WJ-MSCs incorporated with GO in therapy. This study aims to explore the unique gene expression profiles and epigenetic characteristics of WJ-MSCs influenced by GO.

    METHODS AND RESULTS: The characterized GO-coated coverslip served as a substrate for culturing WJ-MSCs. In addition to investigating the impact of GO on cell proliferation and differentiation, we conducted a gene expression study using PCR array, while epigenetic control was assessed through bisulfite sequencing and Western blot analysis. Our findings indicate that the presence of GO maintained the proliferation and survival of WJ-MSCs. In the absence of induction, GO led to minor lipid and glycosaminoglycan deposition in WJ-MSCs. This was evidenced by the sustained expression of pluripotency and lineage-specific genes, demethylation at the OCT4 promoter, and a decrease in H3K9 methylation. In osteo-induced condition, the occurrence of osteogenesis appeared to be guided by BMP/TGF and ERK pathway activation, accompanied by the upregulation of osteogenic-related genes and downregulation of DNMT3b.

    CONCLUSIONS: GO in osteo-induced condition create a favorable microenvironment that promotes the osteogenesis of WJ-MSCs by influencing genetic and epigenetic controls. This helps in advancing our knowledge on the use of GO as priming platform and WJ-MSCs an alternate source for bone repair and regeneration.

    Matched MeSH terms: Graphite*
  9. Fulltext A carrier velocity model for electrical detection of gas molecules
    Hosseingholi Pourasl A, Ariffin SHS, Ahmadi MT, Ismail R, Gharaei N
    Beilstein J Nanotechnol, 2019;10:644-653.
    PMID: 30931206 DOI: 10.3762/bjnano.10.64
    Nanomaterial-based sensors with high sensitivity, fast response and recovery time, large detection range, and high chemical stability are in immense demand for the detection of hazardous gas molecules. Graphene nanoribbons (GNRs) which have exceptional electrical, physical, and chemical properties can fulfil all of these requirements. The detection of gas molecules using gas sensors, particularly in medical diagnostics and safety applications, is receiving particularly high demand. GNRs exhibit remarkable changes in their electrical characteristics when exposed to different gases through molecular adsorption. In this paper, the adsorption effects of the target gas molecules (CO and NO) on the electrical properties of the armchair graphene nanoribbon (AGNR)-based sensor are analytically modelled. Thus, the energy dispersion relation of AGNR is developed considering the molecular adsorption effect using a tight binding (TB) method. The carrier velocity is calculated based on the density of states (DOS) and carrier concentration (n) to obtain I-V characteristics and to monitor its variation in the presence of the gas molecules. Furthermore, the I-V characteristics and energy band structure of the AGNR sensor are simulated using first principle calculations to investigate the gas adsorption effects on these properties. To ensure the accuracy of the proposed model, the I-V characteristics of the AGNR sensor that are simulated based both on the proposed model and first principles calculations are compared, and an acceptable agreement is achieved.
    Matched MeSH terms: Graphite
  10. Fulltext Highly exposed {001} facets of titanium dioxide modified with reduced graphene oxide for dopamine sensing
    How GT, Pandikumar A, Ming HN, Ngee LH
    Sci Rep, 2014;4:5044.
    PMID: 24853929 DOI: 10.1038/srep05044
    Titanium dioxide (TiO2) with highly exposed {001} facets was synthesized through a facile solvo-thermal method and its surface was decorated by using reduced graphene oxide (rGO) sheets. The morphology and chemical composition of the prepared rGO/TiO2 {001} nanocomposite were examined by using suitable characterization techniques. The rGO/TiO2 {001} nanocomposite was used to modify glassy carbon electrode (GCE), which showed higher electrocatalytic activity towards the oxidation of dopamine (DA) and ascorbic acid (AA), when compared to unmodified GCE. The differential pulse voltammetric studies revealed good sensitivity and selectivity nature of the rGO/TiO2 {001} nanocomposite modified GCE for the detection of DA in the presence of AA. The modified GCE exhibited a low electrochemical detection limit of 6 μM over the linear range of 2-60 μM. Overall, this work provides a simple platform for the development of GCE modified with rGO/TiO2 {001} nanocomposite with highly exposed {001} facets for potential electrochemical sensing applications.
    Matched MeSH terms: Graphite/chemistry*
  11. Fulltext Simple room-temperature preparation of high-yield large-area graphene oxide
    Huang NM, Lim HN, Chia CH, Yarmo MA, Muhamad MR
    Int J Nanomedicine, 2011;6:3443-8.
    PMID: 22267928 DOI: 10.2147/IJN.S26812
    Graphene has attracted much attention from researchers due to its interesting mechanical, electrochemical, and electronic properties. It has many potential applications such as polymer filler, sensor, energy conversion, and energy storage devices. Graphene-based nanocomposites are under an intense spotlight amongst researchers. A large amount of graphene is required for preparation of such samples. Lately, graphene-based materials have been the target for fundamental life science investigations. Despite graphene being a much sought-after raw material, the drawbacks in the preparation of graphene are that it is a challenge amongst researchers to produce this material in a scalable quantity and that there is a concern about its safety. Thus, a simple and efficient method for the preparation of graphene oxide (GO) is greatly desired to address these problems. In this work, one-pot chemical oxidation of graphite was carried out at room temperature for the preparation of large-area GO with ~100% conversion. This high-conversion preparation of large-area GO was achieved using a simplified Hummer's method from large graphite flakes (an average flake size of 500 μm). It was found that a high degree of oxidation of graphite could be realized by stirring graphite in a mixture of acids and potassium permanganate, resulting in GO with large lateral dimension and area, which could reach up to 120 μm and ~8000 μm(2), respectively. The simplified Hummer's method provides a facile approach for the preparation of large-area GO.
    Matched MeSH terms: Graphite/chemical synthesis*; Graphite/chemistry
  12. Fulltext Graphene oxide-ellagic acid nanocomposite as effective anticancer and antimicrobial agent
    Hussein-Al-Ali SH, Abudoleh SM, Hussein MZ, Bullo S, Palanisamy A
    IET Nanobiotechnol, 2021 Feb;15(1):79-89.
    PMID: 34694731 DOI: 10.1049/nbt2.12009
    In this study, ellagic acid (ELA), a skin anticancer drug, is capped on the surface(s) of functionalised graphene oxide (GO) nano-sheets through electrostatic and π-π staking interactions. The prepared ELA-GO nanocomposite have been thoroughly characterised by using eight techniques: Fourier-transform infrared spectroscopy (FTIR), zeta potential, X-ray diffraction (XRD), thermogravimetric analysis (TGA), Raman spectroscopy, atomic force microscopy (AFM) topographic imaging, transmission electron microscopy (TEM), and surface morphology via scanning electron microscopy (SEM). Furthermore, ELA drug loading and release behaviours from ELA-GO nanocomposite were studied. The ELA-GO nanocomposite has a uniform size distribution averaging 88 nm and high drug loading capacity of 30 wt.%. The in vitro drug release behaviour of ELA from the nanocomposite was investigated by UV-Vis spectrometry at a wavelength of λmax 257 nm. The data confirmed prolonged ELA release over 5000 min at physiological pH (7.4). Finally, the IC50 of this ELA-GO nanocomposite was found to be 6.16 µg/ml against B16 cell line; ELA and GO did not show any cytotoxic effects up to 50 µg/ml on the same cell lines.
    Matched MeSH terms: Graphite*
  13. Fulltext Evaluation of the Compatibility of Organosolv Lignin-Graphene Nanoplatelets with Photo-Curable Polyurethane in Stereolithography 3D Printing
    Ibrahim F, Mohan D, Sajab MS, Bakarudin SB, Kaco H
    Polymers (Basel), 2019 Sep 23;11(10).
    PMID: 31547544 DOI: 10.3390/polym11101544
    In this study, lignin has been extracted from oil palm empty fruit bunch (EFB) fibers via an organosolv process. The organosolv lignin obtained was defined by the presence of hydroxyl-containing molecules, such as guaiacyl and syringyl, and by the presence of phenolic molecules in lignin. Subsequently, the extracted organosolv lignin and graphene nanoplatelets (GNP) were utilized as filler and reinforcement in photo-curable polyurethane (PU), which is used in stereolithography 3D printing. The compatibility as well as the characteristic and structural changes of the composite were identified through the mechanical properties of the 3D-printed composites. Furthermore, the tensile strength of the composited lignin and graphene shows significant improvement as high as 27%. The hardness of the photo-curable PU composites measured by nanoindentation exhibited an enormous improvement for 0.6% of lignin-graphene at 92.49 MPa with 238% increment when compared with unmodified PU.
    Matched MeSH terms: Graphite
  14. Fulltext Cadmium Sulphide-Reduced Graphene Oxide-Modified Photoelectrode-Based Photoelectrochemical Sensing Platform for Copper(II) Ions
    Ibrahim I, Lim HN, Huang NM, Pandikumar A
    PLoS One, 2016;11(5):e0154557.
    PMID: 27176635 DOI: 10.1371/journal.pone.0154557
    A photoelectrochemical (PEC) sensor with excellent sensitivity and detection toward copper (II) ions (Cu2+) was developed using a cadmium sulphide-reduced graphene oxide (CdS-rGO) nanocomposite on an indium tin oxide (ITO) surface, with triethanolamine (TEA) used as the sacrificial electron donor. The CdS nanoparticles were initially synthesized via the aerosol-assisted chemical vapor deposition (AACVD) method using cadmium acetate and thiourea as the precursors to Cd2+ and S2-, respectively. Graphene oxide (GO) was then dip-coated onto the CdS electrode and sintered under an argon gas flow (50 mL/min) for the reduction process. The nanostructured CdS was adhered securely to the ITO by a continuous network of rGO that also acted as an avenue to intensify the transfer of electrons from the conduction band of CdS. The photoelectrochemical results indicated that the ITO/CdS-rGO photoelectrode could facilitate broad UV-visible light absorption, which would lead to a higher and steady-state photocurrent response in the presence of TEA in 0.1 M KCl. The photocurrent decreased with an increase in the concentration of Cu2+ ions. The photoelectrode response for Cu2+ ion detection had a linear range of 0.5-120 μM, with a limit of detection (LoD) of 16 nM. The proposed PEC sensor displayed ultra-sensitivity and good selectivity toward Cu2+ ion detection.
    Matched MeSH terms: Graphite/chemistry*
  15. Selective and sensitive visible-light-prompt photoelectrochemical sensor of Cu2+ based on CdS nanorods modified with Au and graphene quantum dots
    Ibrahim I, Lim HN, Huang NM, Jiang ZT, Altarawneh M
    J Hazard Mater, 2020 06 05;391:122248.
    PMID: 32062348 DOI: 10.1016/j.jhazmat.2020.122248
    Nowadays, increasing the risk for copper leaching into the drinking water in homes, hotels and schools has become unresolved issues all around the countries such as Canada, the United States, and Malaysia. The leaching of copper in tap water is due to a combination of acidic water, damaged pipes, and corroded plumbing fixtures. To remedy this global problem, a triple interconnected structure of CdS/Au/GQDs was designed as a photo-to-electron conversion medium for a real time and selective visible-light-prompt photoelectrochemical (PEC) sensor for Cu2+ ions in real water samples. The synergistic interaction of the CdS/Au/GQDs enabled the smooth transportation of charge carriers to the charge collector and provided a channel to inhibit the charge recombination reaction. Thus, a detection limit of 2.27 nM was obtained, which is 10,000 fold lower than that of WHO's Guidelines for Drinking-water Quality (∼30 μM). The photocurrent reduction was negligible after 30 days of storage under ambient conditions, suggesting the high stability of photoelectrode. Moreover, the real-time monitoring of Cu2+ ions in real samples was performed with satisfactory results, confirming the capability of the investigated photoelectrode as the most practical detector for trace amounts of Cu2+ ions.
    Matched MeSH terms: Graphite/chemistry
  16. Fulltext Synthesis and Characterization of Graphene Oxide/Polyethylene Glycol/Folic Acid/Brucine Nanocomposites and Their Anticancer Activity on HepG2 Cells
    Ibrahim IAA, Alzahrani AR, Alanazi IM, Shahzad N, Shahid I, Falemban AH, et al.
    Int J Nanomedicine, 2024;19:1109-1124.
    PMID: 38344441 DOI: 10.2147/IJN.S445206
    BACKGROUND: Liver cancer is the sixth most prevalent form of cancer and the second major cause of cancer-associated mortalities worldwide. Cancer nanotechnology has the ability to fundamentally alter cancer treatment, diagnosis, and detection.

    OBJECTIVE: In this study, we explained the development of graphene oxide/polyethylene glycol/folic acid/brucine nanocomposites (GO/PEG/Bru-FA NCs) and evaluated their antimicrobial and anticancer effect on the liver cancer HepG2 cells.

    METHODOLOGY: The GO/PEG/Bru-FA NCs were prepared using the co-precipitation technique and characterized using various techniques. The cytotoxicity of the GO/PEG/Bru-FA NCs was tested against both liver cancer HepG2 and non-malignant Vero cells using an MTT assay. The antimicrobial activity of the GO/PEG/Bru-FA NCs was tested against several pathogens using the well diffusion technique. The effects of GO/PEG/Bru-FA NCs on endogenous ROS accumulation, apoptosis, and MMP levels were examined using corresponding fluorescent staining assays, respectively. The apoptotic protein expressions, such as Bax, Bcl-2, and caspases, were studied using the corresponding kits.

    RESULTS: The findings of various characterization assays revealed the development of GO/PEG/Bru-FA NCs with face-centered spherical morphology and an agglomerated appearance with an average size of 197.40 nm. The GO/PEG/Bru-FA NCs treatment remarkably inhibited the growth of the tested pathogens. The findings of the MTT assay evidenced that the GO/PEG/Bru-FA NCs effectively reduced the HepG2 cell growth while not showing toxicity to the Vero cells. The findings of the fluorescent assay proved that the GO/PEG/Bru-FA NCs increased ROS generation, reduced MMP levels, and promoted apoptosis in the HepG2 cells. The levels of Bax, caspase-9, and -3 were increased, and Bcl-2 was reduced in the GO/PEG/Bru-FA NCs-treated HepG2 cells.

    CONCLUSION: The results of this work demonstrate that GO/PEG/Bru-FA NCs suppress viability and induce apoptosis in HepG2 cells, indicating their potential as an anticancer candidate.

    Matched MeSH terms: Graphite*
  17. Fulltext Complex Permittivity and Electromagnetic Interference Shielding Effectiveness of OPEFB Fiber-Polylactic Acid Filled with Reduced Graphene Oxide
    Ibrahim Lakin I, Abbas Z, Azis RS, Abubakar Alhaji I
    Materials (Basel), 2020 Oct 16;13(20).
    PMID: 33081082 DOI: 10.3390/ma13204602
    This study was aimed at fabricating composites of polylactic acid (PLA) matrix-reinforced oil palm empty fruit bunch (OPEFB) fiber filled with chemically reduced graphene oxide (rGO). A total of 2-8 wt.% rGO/OPEFB/PLA composites were characterized for their complex permittivity using an open-ended coaxial probe (OEC) technique. The shielding efficiency properties were calculated using the measured transmission (S21) and the reflection (S11) coefficient results. All the measurements and calculations were performed in the 8-12 GHz frequency range. The morphological and microstructural study included X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and Fourier transform infrared spectroscopy (FTIR). The results indicated that the incorporation of rGO as filler into the composites enhanced their complex permittivity properties. The composites showed a total shielding efficiency (SET) of about 31.2 dB at a frequency range of 8-12 GHz, which suggests their usefulness for microwave absorption.
    Matched MeSH terms: Graphite
  18. Graphene-Based Materials as Solid Phase Extraction Sorbent for Trace Metal Ions, Organic Compounds, and Biological Sample Preparation
    Ibrahim WA, Nodeh HR, Sanagi MM
    Crit Rev Anal Chem, 2016 Jul 03;46(4):267-83.
    PMID: 26186420 DOI: 10.1080/10408347.2015.1034354
    Graphene is a new carbon-based material that is of interest in separation science. Graphene has extraordinary properties including nano size, high surface area, thermal and chemical stability, and excellent adsorption affinity to pollutants. Its adsorption mechanisms are through non-covalent interactions (π-π stacking, electrostatic interactions, and H-bonding) for organic compounds and covalent interactions for metal ions. These properties have led to graphene-based material becoming a desirable adsorbent in a popular sample preparation technique known as solid phase extraction (SPE). Numerous studies have been published on graphene applications in recent years, but few review papers have focused on its applications in analytical chemistry. This article focuses on recent preconcentration of trace elements, organic compounds, and biological species using SPE-based graphene, graphene oxide, and their modified forms. Solid phase microextraction and micro SPE (µSPE) methods based on graphene are discussed.
    Matched MeSH terms: Graphite/chemistry*
  19. Fulltext The microstructure investigation of thionine-graphene nanocomposite using SEM
    Ibrahim, M.A., Jani, N.A.M., Kudin, T.I.T., Ali, A.M.M., Yusof, R.M., Hassan, O.H.
    Scientific Research Journal, 2015;12(2):0-0.
    MyJurnal
    Materials that can enhance the sensitivity and selectivity of a biosensor are greatly in demand. The nanocomposition of thionine (Th) and graphene can increase the electroconductivity of the working electrode used. Graphene is a very good electrical conductor but is also hydrophobic in nature. Composition with thionine gives it the capability to disperse well in water. Plus, thionine provides the opportunity for DNA probes to be immobilized due to the presence of the amino group in its structure. In this research, the thionine-graphene (Th-G) nanocomposite was synthesized through filtration and characterised using scanning electron microscopy (SEM) to distinguish different elements coexist in the nanocomposite and to investigate the microstructure changes of the nanocomposite to confirm the composition. Different elements were analyzed to test the presence of both thionine and graphene in the composition. Physical characterisation through SEM proved the nanocomposition was a success.
    Matched MeSH terms: Graphite
  20. Simultaneous naphthalene degradation and electricity production in a biowaste-powered microbial fuel cell
    Idris MO, Mohamad Ibrahim MN, Md Noh NA, Yaqoob AA, Hussin MH, Mohamad Shukri IA, et al.
    Chemosphere, 2023 Nov;340:139985.
    PMID: 37640217 DOI: 10.1016/j.chemosphere.2023.139985
    Naphthalene is a very common and hazardous environmental pollutant, and its biodegradation has received serious attention. As demonstrated in this study, naphthalene-contaminated wastewater can be biodegraded using a microbial fuel cell (MFC). Furthermore, the potential of MFC for electricity generation appears to be a promising technology to meet energy demands other than those produced from fossil fuels. Nowadays, efforts are being made to improve the overall performance of MFC by integrating biowaste materials for anode fabrication. In this study, palm kernel shell waste was used to produce palm kernel shell-derived graphene oxide (PKS-GO) and palm kernel shell-derived reduced graphene oxide (PKS-rGO), which were then fabricated into anode electrodes to improve the system's electron mobilization and transport. The MFC configuration with the PKS-rGO anode demonstrated greater energy production potential, with a maximum power density of 35.11 mW/m2 and a current density of 101.76 mA/m2, compared to the PKS-GO anode, which achieved a maximum power density of 17.85 mW/m2 and a current density of 72.56 mA/m2. Furthermore, there is simultaneous naphthalene biodegradation with energy production, where the biodegradation efficiency of naphthalene with PKS-rGO and PKS-GO is 85.5%, and 79.7%, respectively. In addition, the specific capacitance determined from the cyclic voltammetry curve revealed a value for PKS-rGO of 2.23 × 10-4 F/g, which is also higher than the value for PKS-GO (1.57 × 10-4 F/g) on the last day of operation. Anodic microbial analysis shows that electrogens thrive in the MFC process. Finally, a comparison with previous literature and the future prospects of the study are also presented.
    Matched MeSH terms: Graphite*
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