Multilayered graphene/ZnFe2O4 hybrid composite: Rational preparation, characterization and superior adsorption of Congo red

Multilayered porous hierarchical structure of graphene/ZnFe2O4 hybrids was prepared via in situ hydrothermal growth of ZnFe2O4 nanocrystals within interlayer space of reduced graphene oxide, which demonstrated a high specific area of 117 m2∙g−1 and rational porous structures. Batch adsorption studies showed that the product possesses superior adsorption capacity of dyes such as Congo red from aqueous solution. Adsorption equilibrium and kinetic analysis indicated that the adsorption isotherm was well fitted by Langmuir isothermal model with the maximum adsorption capacity of 404.12 mg∙g−1, and the adsorption kinetics followed the pseudo-second-order kinetic equation. Furthermore, this new product can be magnetically separated and regenerated easily, presenting an effective adsorbent for wastewater purification

Structural and optical properties of Fe3O4@Au/rGO nanocomposites synthesized by hydrothermal method and their photothermal effect under NIR laser irradiation

One of the most promising methods of heat generation is using the nanosources, as absorbent light, under near-infrared (NIR) irradiation. Here, the Fe3O4@Au/rGO nanocomposites (NCs) with various graphene content (10, 25, and 40 wt) synthesized by hydrothermal reaction method. The heat generated by Fe3O4@Au/rGO NCs suspensions under NIR laser irradiation (808 nm) in various concentration and times has been experimentally determined. The physical characteristics of these nanocomposite were studied using FE-SEM, TEM, XRD, XPS, FTIR, UV�vis, and Raman techniques. TEM and FE-SEM images displayed the spherical shape of Fe3O4@Au NCs which had varying diameter from 20 to 30 nm, coated to rGO sheets (with ~1 μm lateral dimension). The results demonstrate that the temperature of suspension under NIR laser irradiation raises from 5 to 40 °C with the increase of both the graphene contents and concentration. The Fe3O4@Au/rGO NCs are proposed as promising nanosources for heat generation under NIR laser irradiation and are useful for photothermal therapy, biomedical imaging, photothermal imaging, catalysis, and sensors applications. © 2020 Elsevier B.V

Fe3O4@Au/reduced graphene oxide nanostructures: Combinatorial effects of radiotherapy and photothermal therapy on oral squamous carcinoma KB cell line

Combination therapy including radiotherapy (RT) and photothermal therapy (PTT), as an alternative treatment for cancer treatment, recently has generated substantial interest. Graphene-based nanocarbons and gold content metallic nanoparticles, as one of the most attractive materials with their extraordinary physical and chemical properties, are extremely useful in this regard. We herein reported the effects of combination of cancer therapy including RT (doses of 2 and 4 Gy) and PTT (808 nm laser irradiation, NIR irradiation) as radio-photothermal therapy (RPTT) of KB oral squamous carcinoma cell line in the presence of Fe3O4@Au/reduced graphene oxide (rGO) nanostructures (NSs) at different concentrations. Fe3O4@Au/rGO NSs with different rGO contents have been synthesized by hydrothermal reaction method. They characterized by XRD, FE-SEM, TEM, EDS, FTIR and TGA. Cell viability for cytotoxicity, RT, PTT and RPTT were studied by MTT (3-4,5-dimethylthiazol-2-yl-2, 5-diphenyltetrazolium bromide) assay. High photothermal conversion efficiency of Fe3O4@Au/rGO NSs reaches to 61%. The resulting Fe3O4@Au NPs with approximate size of about 10�60 nm covered the rGO nanosheets with 40 wt% rGO at concentration of 20 μg ml�1, exhibited satisfactory cytotoxicity. They provided significant cell destruction under RT, PTT and specially RPTT in dose of 4 Gy. Furthermore, they have good biocompatibility on the healthy cells. Our results show that Fe3O4@Au/rGO NSs integrated with radiosensitization, photothermal therapy and their combination promising for nanomedicine and clinical applications. © 2020 Elsevier Ltd and Techna Group S.r.l

ZnFe2O4 nanoparticles as radiosensitizers in radiotherapy of human prostate cancer cells

Nanoparticles of high-Z elements exhibit stronger photoelectric effects than soft tissues under gamma irradiation. Hence, they can be used as effective radiosensitizers for increasing the efficiency of current radiotherapy. In this work, superparamagnetic zinc ferrite spinel (ZnFe2O4) nanoparticles were synthesized by a hydrothermal reaction method and used as radiosensitizers in cancer therapy. The magnetic nanoparticles showed fast separation from solutions (e.g., ~ 1 min for 2 mg mL- 1 of the nanoparticles in ethanol) by applying an external magnetic field (~ 1 T). The ZnFe2O4 nanoparticles were applied in an in vitro radiotherapy of lymph node carcinoma of prostate cells (as high radioresistant cells) under gamma irradiation of 60Co source. The nanoparticles exhibited no significant effects on the cancer cells up to the high concentration of 100 μg mL- 1, in the absence of gamma irradiation. The gamma irradiation alone (2 Gy dose) also showed no significant effects on the cells. However, gamma irradiation in the presence of 100 μg mL- 1 ZnFe2O4 nanoparticles resulted in ~ 53 inactivation of the cells (~ 17 times higher than the inactivation that occurred under gamma irradiation alone) after 24 h. The higher cell inactivation was assigned to interaction of gamma radiation with nanoparticles (photoelectric effect), resulting in a high level electron release in the media of the radioresistant cells. Our results indicated that ZnFe2O4 nanoparticles not only can be applied in increasing the efficiency of radiotherapy, but also can be easily separated from the cell environment by using an external magnetic field after the radiotherapy. © 2014 Elsevier B.V. All rights reserved

Structural, optical and dielectric studies of Ag nanoparticles decorated by herceptin

Silver nanoparticles (AgNPs) were synthesized (with 17�31 nm sizes) by reduction of AgNO3 by NaBH4 solution and covered by anti-HER2 monoclonal antibody (Herceptin). The morphology, structure, optical and dielectric properties of the prepared AgNPs have been characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), UV�Vis system and Fourier transform infrared (FTIR) spectroscopy. The complex index of refraction and the dielectric coefficient Herceptin and AgNPs covered by Herceptin were measured over the spectral region of 400�4000 cm�1. The XRD patterns showed the formation of face-centered cubic lattice structure of AgNPs and according to the TEM image AgNPs had spherical shape with an average diameter size of about 25 nm. By using Kramers�Kronig (KK) dispersion relations analysis, these measurements allow the determination of the real and imaginary parts of refractive index and dielectric coefficient over the entire wavelength intervals. By covering AgNPs with antibody, the intensity of n and k peaks were decreased. After decoration with AgNPs, the real and imaginary parts of permittivity in samples were also decreased. In addition, the resonance frequency of decorated samples with AgNPs have red shifts in comparison with the pure samples. These results are applicable in development of methods for detection of airborne pathogenic agent. © 2019 Elsevier B.V