Search Results (98)

Nanotechnology has emerged as a highly focused field of research due to the unique properties of nanometric materials, particularly their large specific surface areas and excellent adsorption capabilities. This study investigated the synthesis of materials based on graphene oxide (GO) functionalized with different metal oxides (MnO₂, Fe₃O₄, CuO, NiO), with potential applications in water decontamination. The morphological, structural, and compositional properties of these nanocomposites were extensively characterized using different experimental techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometry (VSM) for magnetic property evaluation. Preliminary adsorption tests were performed for the removal of pesticides and drugs from aqueous solutions. The synthesized materials demonstrated a higher affinity for selected pesticides compared to drugs. The best removal efficiencies were 98.59% for cymoxanil, 97.93% for triadimefon, 63.33% for sulfamethoxazole, and 99.59% for diclofenac. The results indicate that the functionalization of GO with metal oxides modifies the material’s structure, increasing its potential for environmental applications such as water purification. Full article

Glucose detection is critical in addressing health and medical issues related to irregular blood levels. Colorimetry, a simple, cost-effective, and visually straightforward method, is often employed. Traditional enzymatic detection methods face drawbacks such as high costs, limited stability, and operational challenges. To overcome these, enzyme mimics or artificial nano-enzymes based on inorganic nanomaterials have garnered attention, but their cost and susceptibility to inactivation limit applications. This study presents a ZnFe₂O₄/GQDs nanocomposite as an innovative enzyme mimic, addressing key requirements like low cost, high stability, biocompatibility, and wide operational range. Synthesized using a simple and inexpensive method, the composite benefits from the synergistic interaction between ZnFe₂O₄ nanoparticles and graphene quantum dots (GQDs), resulting in excellent magnetic properties, high surface area, and functional versatility. The material demonstrated remarkable sensitivity with a detection limit of 7.0 μM across a range of 5–500 μM and achieved efficient peroxidase-like activity with Km values of 0.072 and 0.068 mM and Vmax of 4.58 × 10⁻⁸ and 8.29 × 10⁻⁸ M/s for TMB and H₂O₂, respectively. The nanocomposite also exhibited robust recyclability, retaining performance over six reuse cycles. Full article

The primary resonance responses of high-performance nanocomposite materials used in spacecraft components in complex electromagnetic field environments were investigated. Simultaneously considering the interfacial effect, agglomeration effect, and percolation threshold, a theoretical model that can predict Young’s modulus and electrical conductivity of graphene nanocomposites is developed by the effective medium theory (EMT), shear lag theory, and the Mori-Tanaka method. The magnetoelastic vibration equation for an axially moving graphene nanocomposite current-carrying beam was derived via the Hamilton principle. The amplitude-frequency response equations were obtained for different external loading conditions. The study reveals the significant role of graphene concentration, external force, and magnetic field on the system’s primary resonance, highlighting how electromagnetic forces play a critical role similar to external excitation forces. It is shown that the increase in graphene content could lead the system from period-doubling motion into chaotic behavior. Moreover, an enhanced magnetic field strength may lower the minimum graphene concentration needed for period-doubling motion. This work provides new insights into controlling nonlinear vibrations of such systems through applied electromagnetic fields, emphasizing the importance of designing multifunctional nanocomposites in multi-physics coupled environments. The concentration of graphene filler would significantly affect the primary resonance and bifurcation and chaos behaviors of the system. Full article

Magnetic ionic liquid (MIL) based on alkyl phosphonium cation was used as a curing agent for developing epoxy nanocomposites (ENCs) modified with a graphene nanoplatelet (GNP)/carbon nanotube (CNT) hybrid filler. The materials were prepared by a solvent-free procedure involving ball-milling technology. ENCs containing as low as 3 phr of filler (GNP/CNT = 2.5:0.5 phr) exhibited electrical conductivity with approximately six orders of magnitude greater than the system loaded with GNP = 2.5 phr. Moreover, the use of MIL (10 phr) resulted in ENCs with higher conductivity compared with the same system cured using conventional aliphatic amine. The filler dispersion within the epoxy matrix was confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electromagnetic interference shielding effectiveness (EMI SE), evaluated in the X- and Ku-band frequency range, revealed a great contribution of the absorption mechanism for the ENC containing the hybrid filler and cured with MIL. Moreover, the best microwave-absorbing response was achieved with the ENC containing GNP/CNT = 2.5/0.5 phr, and cured with ML, which a minimum RL of −23.61 dB and an effective absorption bandwidth of 5.18 GHz were observed for thickness of 1.5 mm. In summary, this system is a promising material for both civilian and military applications due to its simple and scalable nanocomposite preparation method, the lightweight nature of the composites resulting from the low filler content, the commercial availability and cost-effectiveness of GNP, and its high electromagnetic wave attenuation across a broad frequency range. Full article

Detecting multiple tumor markers is of great importance. It helps in early cancer detection, accurate diagnosis, and monitoring treatment. In this work, gold nanoparticles–toluidine blue–graphene oxide (AuNPs-TB–GO) and gold nanoparticles–carboxyl ferrocene–tungsten disulfide (AuNPs–FMC–WS₂) nanocomposites were prepared for labeling Carcinoembryonic antigen (CEA) antibody and Carbohydrate antigen 72–4 (CA72-4) antibody, respectively, and used as two kinds of probes with different electrochemical signals. With the excellent magnetic performance of biotin immune magnetic beads (IMBs), the biofunctional IMBs were firmly deposited on the magnetic glassy carbon electrode (MGCE) surface by applying a constant magnetic field, and then the CEA and CA72-4 antibody were immobilized on the IMBs by the avidin–biotin conjugation. The assay was based on the change in the detection peak current. Under the optimum experimental conditions, the linear range of detection of CEA is of the two-component immunosensor is from 0.01 to 120 ng/mL, with a low detection limit of 0.003 ng/mL, and the linear range of detection of CA72-4 is from 0.05 to 35 U/mL, with a detection limit of 0.016 U/mL. The results showed that the proposed immunosensor enabled simultaneous monitoring of CEA and CA72-4 and exhibited good reproducibility, excellent high selectivity, and sensitivity. In particular, the proposed multiplexed immunoassay approach does not require sophisticated fabrication and is well-suited for high-throughput biosensing and application to other areas. Full article

Nanocomposites based on Fe₃O₄ and carbonaceous nanoparticles (CNPs), including carbon nanotubes (CNTs) and graphene derivatives (graphene oxide (GO) and reduced graphene oxide (RGO)), such as Fe₃O₄@GO, Fe₃O₄@RGO, and Fe₃O₄@CNT, have demonstrated considerable potential in a number of health applications, including tissue regeneration and innovative cancer treatments such as hyperthermia (HT). This is due to their ability to transport drugs and generate localized heat under the influence of an alternating magnetic field on Fe₃O₄. Despite the promising potential of CNTs and graphene derivatives as drug delivery systems, their use in biological applications is hindered by challenges related to dispersion in physiological media and particle agglomeration. Hence, a solid foundation has been established for the integration of various synthesis techniques for these nanocomposites, with the wet co-precipitation method being the most prevalent. Moreover, the dimensions and morphology of the composite nanoparticles are directly correlated with the value of magnetic saturation, thus influencing the efficiency of the composite in drug delivery and other significant biomedical applications. The current demand for this type of material is related to the loading of a larger quantity of drugs within the hybrid structure of the carrier, with the objective of releasing this amount into the tumor cells. A second demand refers to the biocompatibility of the drug carrier and its capacity to permeate cell membranes, as well as the processes occurring within the drug carriers. The main objective of this paper is to review the synthesis methods used to prepare hybrids based on Fe₃O₄ and CNPs, such as GO, RGO, and CNTs, and to examinate their role in the formation of hybrid nanoparticles and the correlation between their morphology, the dimensions, and optical/magnetic properties. Full article

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. Full article

Graphene oxide and its magnetic nanoparticle-based composites are a well-known tool to remove heavy metals from wastewater. Unfortunately, one of the major issues in handling such small particles consists of their difficult removal from treated wastewater (even when their magnetic properties are exploited), due to their very small diameter. One possible way to overcome this problem is to embed them in a macroscopic biopolymer matrix, such as alginate or chitosan beads. In this way, the adsorbent becomes easier to handle and can be used to build, for example, a packed column, as in a traditional industrial adsorber. In this work, the removal performances of two different embedded magnetic nanocomposite adsorbents (MNAs) are discussed. The first type of MNA is based on ferrite magnetic nanoparticles (MNPs) generated by coprecipitation using iron(II/III) salts and ammonium hydroxide, while the second is based on a 2D material composed of MNP-decorated graphene oxide. Both MNAs were embedded in cross-linked alginate beads and used to treat artificial water contaminated with chromium(III), nickel(II), and copper(II) in different concentrations. The yield of removal and differences between MNAs and non-embedded magnetic nanomaterials are also discussed. From the results, it was found that the time to reach the adsorption equilibrium is higher when compared to that of the nanomaterials only, due to the lower surface/volume ratio of the beads, but the adsorption capacity is higher, due to the additional interaction with alginate. Full article

Shape memory and self-healing polymer nanocomposites have attracted considerable attention due to their modifiable properties and promising applications. The incorporation of nanomaterials (polypyrrole, carboxyl methyl cellulose, carbon nanotubes, titania nanotubes, graphene, graphene oxide, mesoporous silica) into these polymers has significantly enhanced their performance, opening up new avenues for diverse applications. The self-healing capability in polymer nanocomposites depends on several factors, including heat, quadruple hydrogen bonding, π–π stacking, Diels–Alder reactions, and metal–ligand coordination, which collectively govern the interactions within the composite materials. Among possible interactions, only quadruple hydrogen bonding between composite constituents has been shown to be effective in facilitating self-healing at approximately room temperature. Conversely, thermo-responsive self-healing and shape memory polymer nanocomposites require elevated temperatures to initiate the healing and recovery processes. Thermo-responsive (TRSMPs), light-actuated, magnetically actuated, and Electrically actuated Shape Memory Polymer Nanocomposite are discussed. This paper provides a comprehensive overview of the different types of interactions involved in SMP and SHP nanocomposites and examines their behavior at both room temperature and elevated temperature conditions, along with their biomedical applications. Among many applications of SMPs, special attention has been given to biomedical (drug delivery, orthodontics, tissue engineering, orthopedics, endovascular surgery), aerospace (hinges, space deployable structures, morphing aircrafts), textile (breathable fabrics, reinforced fabrics, self-healing electromagnetic interference shielding fabrics), sensor, electrical (triboelectric nanogenerators, information energy storage devices), electronic, paint and self-healing coating, and construction material (polymer cement composites) applications. Full article

(1) Background: Safety problems associated with aflatoxin B₁ (AFB₁) contamination have always been a major threat to human health. Removing AFB₁ through adsorption is considered an attractive remediation technique. (2) Methods: To produce an adsorbent with a high AFB₁ adsorption efficiency, a magnetic reduced graphene oxide composite (Fe₃O₄@rGO) was synthesized using one-step hydrothermal fabrication. Then, the adsorbent was characterized using a series of techniques, such as SEM, TEM, XRD, FT-IR, VSM, and nitrogen adsorption–desorption analysis. Finally, the effects of this nanocomposite on the nutritional components of treated foods, such as vegetable oil and peanut milk, were also examined. (3) Results: The optimal synthesis conditions for Fe₃O₄@rGO were determined to be 200 °C for 6 h. The synthesis temperature significantly affected the adsorption properties of the prepared material due to its effect on the layered structure of graphene and the loading of Fe₃O₄ nanoparticles. The results of various characterizations illustrated that the surface of Fe₃O₄@rGO had a two-dimensional layered nanostructure with many folds and that Fe₃O₄ nanoparticles were distributed uniformly on the surface of the composite material. Moreover, the results of isotherm, kinetic, and thermodynamic analyses indicated that the adsorption of AFB₁ by Fe₃O₄@rGO conformed to the Langmuir model, with a maximum adsorption capacity of 82.64 mg·g⁻¹; the rapid and efficient adsorption of AFB₁ occurred mainly through chemical adsorption via a spontaneous endothermic process. When applied to treat vegetable oil and peanut milk, the prepared material minimized the loss of nutrients and thus preserved food quality. (4) Conclusions: The above findings reveal a promising adsorbent, Fe₃O₄@rGO, with favorable properties for AFB₁ adsorption and potential for food safety applications. Full article

Civil engineering structures need to be protected from earthquakes, representing a new area of research that is growing continuously and very rapidly. Design engineers are always searching for lightweight, stronger, and stiffer materials to be applied as vibration-damping materials. Stability in dynamics necessitates an active, robust, and convenient mechanism that can absorb the kinetic energy of vibration to prevent the structural system from resonance. Recently, many researchers have successfully used nanomaterials to develop energy-absorbing materials that are lightweight and cost-effective. Traditional damping treatments are based on combinations of viscoelastic, elastomeric, magnetic, and piezoelectric materials. In this paper, a review of various damping techniques for composites made of cement modified by various nanomaterials like Nano Al2O₃ (Aluminum Dioxide), Nano SiO₂ (Silicon Dioxide), Nano TiO₂ (Titanium Dioxide), Graphene, and CNTs (Carbon Nanotubes) is presented. The designs of various nano-composite dampers are presented to strengthen the information progress in this field. The current study’s goal is to discover how nanoparticles impact the cement-based material’s damping properties. The study examined several nanomaterials in cement composites at differing concentrations. With the help of the Dynamic Mechanical Analysis (DMA) method and the Logarithmic Decrement approach, the damping properties of these composites were examined. Scanning Electron Microscopy (SEM) was used to examine the effects of nanomaterials on the microstructure and pore size distribution of the composite. Increasing the quantity of nanoparticles in cement paste may improve its capacity to lessen vibration. The experiments also showed that certain nanomaterials may improve load transmission inside the cement matrix and connect neighboring hydration products, helping to reduce energy loss during the loading process. These nanoparticles will eventually replace the large machinery employed to dampen vibrations in buildings due to their small weight, increased mechanical strength, and effective damping properties. Full article

Nanoparticles (e.g., graphene oxide, graphene oxide-Fe₃O₄ nanocomposite or hexagonal boron nitride) loaded with anti-cancer drugs and targeted at cancerous cells allowed researchers to determine the most effective in vitro conditions for anticancer treatment. For this reason, the main propose of the present study was to determine the effect of graphene oxide (GO) with iron oxide (Fe₃O₄) nanoparticles (GO-Fe₃O₄) covalently (c-GO-Fe₃O₄-HCPT) and non-covalently (nc-GO-Fe₃O₄-HCPT) conjugated with hydroxycamptothecin (HCPT) in the presence of a rotating magnetic field (RMF) on relative cell viability using the MCF-7 breast cancer cell line. The obtained GO-Fe₃O₄ nanocomposites demonstrated the uniform coverage of the graphene flakes with the nanospheres, with the thickness of the flakes estimated as ca. 1.2 nm. The XRD pattern of GO–Fe₃O₄ indicates that the crystal structure of the magnetite remained stable during the functionalization with HCPT that was confirmed with FTIR spectra. After 24 h, approx. 49% and 34% of the anti-cancer drug was released from nc-GO-Fe₃O₄-HCPT and c-GO-Fe₃O₄-HCPT, respectively. The stronger bonds in the c-GO-Fe₃O₄-HCPT resulted in a slower release of a smaller drug amount from the nanocomposite. The combined impact of the novel nanocomposites and a rotating magnetic field on MCF-7 cells was revealed and the efficiency of this novel approach has been confirmed. However, MCF-7 cells were more significantly affected by nc-GO-Fe₃O₄-HCPT. In the present study, it was found that the concentration of nc-GO-Fe₃O₄-HCPT and a RMF has the highest statistically significant influence on MCF-7 cell viability. The obtained novel nanocomposites and rotating magnetic field were found to affect the MCF-7 cells in a dose-dependent manner. The presented results may have potential clinical applications, but still, more in-depth analyses need to be performed. Full article

The nanocomposites with reversible cross-linking covalent bonds were prepared by reacting furfurylamine (FA)-modified diglycidyl ether of bisphenol A (DGEBA) and furfuryl-functionalized aniline trimer-modified graphene (TFAT-G) with bismaleimide (BMI) via the Diels-Alder (DA) reaction. The successful synthesis of the TFAT modifier is confirmed by nuclear magnetic resonance (NMR) hydrogen spectroscopy and IR spectroscopy tests. The structure and properties of TFAT-G epoxy nanocomposites are characterized by scanning electron microscopy (SEM), differential scanning calorimeter (DSC), tensile, and resistivity. The results show that TFAT-G was uniformly dispersed in the resin, and 1 wt% TFAT-G composites increased to 233% for tensile strength, 63% for elongation at break, 66% for modulus, and 7.8 °C for Tg. In addition, the addition of unmodified graphene degrades the mechanical properties of the composite. Overall, the graphene/self-healing resin nanocomposites have both good self-healing function and electrical conductivity by adding 1 wt% modified graphene; this allows for the maintenance of the original 83% strength and 89% electrical conductivity after one cycle of heating repair. Full article

Advanced oxidation processes stand as green alternatives for the decontamination of waste waters. Photocatalysis is an advanced oxidation process in which a semiconductor material absorbs photon energy and triggers redox reactions capable of degrading organic pollutants. Titanium dioxide (TiO₂, titania) represents one of the most popular choices of photocatalytic materials, however the UV-activation of its anatase phase and its high charge recombination rate decrease its photocatalytic activity and weaken its potential. Graphene oxide is a 2D carbon nanomaterial consisting of exfoliated sheets of hexagonally arranged carbons decorated with oxygen- and hydrogen- functional groups. Composite nanomaterials consisting of titania nanoparticles and graphene oxide have proven to enhance the photocatalytic activity of pure TiO₂. In this review, we present a thorough literature review of ternary nanocomposites based on synthesized or commercial titania nanoparticles and GO (or reduced GO) particularly used for the photodegradation of dyes. GO/TiO₂ has been enriched primarily with metals, semiconductors and magnetic nanomaterials, proving a superior dye degradation performance and reusability compared to bare TiO₂. Ongoing challenges and perspectives are outlined. Full article