Search

Developing multifunctional theranostic platforms with complementary roles has drawn considerable attention in recent years. In this study, superparamagnetic cobalt ferrite/graphene oxide (CoFe 2 O 4 /GO) nanocomposites with integrated characteristics of magnetic resonance imaging and controlled drug delivery were prepared by sonochemical method. The morphology, microstructure and physical properties of as-prepared CoFe 2 O 4 /GO were investigated in detail by transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Raman spectra, N 2 adsorption/desorption isotherm, thermogravimetric analysis (TGA), superconducting quantum interference device (SQUID) and zeta potential measurements. The obtained CoFe 2 O 4 /GO exhibited superparamagnetic property and dose-dependent T 2 -weighted enhancement effect with relaxivity coefficient of 92.71 mM −1 s −1 . Furthermore, the CoFe 2 O 4 /GO showed negligible cytotoxicity even at a high concentration after being treated for 96 h. Doxorubicin hydrochloride (DOX) as an anti-tumor model drug was loaded on CoFe 2 O 4 /GO. The nanocomposites were found to be able to efficiently transport DOX into the cancer cells and then cause cell death. The drug loading capacity of this nanocarrier was as high as 1.08 mg/mg and the drug release behavior demonstrated a sustained and pH-responsive way. The results suggested that the as-prepared CoFe 2 O 4 /GO showed great potential as an effective multifunctional nanoplatform for magnetic resonance imaging and controlled drug delivery for simultaneous cancer diagnosis and chemotherapy. [ABSTRACT FROM AUTHOR]

In this study, manganese ferrite/graphene oxide (MnFe 2 O 4 /GO) nanocomposites as controlled targeted drug delivery were prepared by a facile sonochemical method. It was found that GO nanosheets were fully exfoliated and decorated with MnFe 2 O 4 nanoparticles having diameters of 5–13 nm. The field-dependent magnetization curve indicated superparamagnetic behavior of the obtained MnFe 2 O 4 /GO with saturation magnetization of 34.9 emu/g at room temperature. The in vitro cytotoxicity testing exhibited negligible cytotoxicity of as-prepared MnFe 2 O 4 /GO even at the concentration as high as 150 μg/mL. Doxorubicin hydrochloride (DOX) as an anti-tumor model drug was utilized to explore the application potential of MnFe 2 O 4 /GO for controlled drug delivery. The drug loading capacity of this nanocarrier was as high as 0.97 mg/mg and the drug release behavior showed a sustained and pH-responsive way. [ABSTRACT FROM AUTHOR]

In this study, cobalt ferrite/graphene oxide (CoFe 2 O 4 /GO) nanocomposites were synthesized successfully by a facile sonochemical method. The microstructure and physical properties of CoFe 2 O 4 /GO nanocomposites were investigated in detail by TEM, XRD and SQUID. It was found that GO nanosheets were fully exfoliated and decorated homogeneously with CoFe 2 O 4 nanoparticles having diameters of 8∼15 nm. The field-dependent magnetization curve indicated superparamagnetic behavior of as-prepared CoFe 2 O 4 /GO with saturation magnetization ( M s ) of 34.9 emu/g at room temperature. The ferrofluid was prepared by the obtained CoFe 2 O 4 /GO with 25 wt% particles and its magnetorheological (MR) properties were tested using a Physica MCR301 rheometer fitted with a magneto-rheological module. The CoFe 2 O 4 /GO-based ferrofluid exhibited typical MR effect with increasing viscosity, shear stress and yield stress depending on the applied magnetic field strength. [ABSTRACT FROM AUTHOR]

Abstract: It is significant interest in developing novel multifunctional nanocarrier with complementary roles in recent years. Magnetic Fe3O4/graphene oxide (GO) nanocomposites with integrated characteristics of magnetic resonance imaging (MRI) and controlled drug delivery were prepared by an inverse co-precipitation method. The microstructure and physical properties of Fe3O4/GO nanocomposites were investigated by transmission electron microscope, wide-angle X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analyzer and superconducting quantum interference device magnetometer. The obtained nanocomposites exhibited superparamagnetic property with the saturation magnetization of 63.3 Am2 kg−1 at room temperature. In vitro MRI experiments revealed that Fe3O4/GO nanocomposites possessed an excellent MRI enhancement effect. 5-Fluorouracil (5-FU) as an anti-tumor model drug was loaded onto the surface of Fe3O4/GO nanocomposites. The drug loading capacity of this nanocarrier was as high as 0.37 mg mg−1 and the drug release behavior showed pH-dependence. The results suggested that the as-prepared Fe3O4/GO nanocomposites showed great potential as an effective multifunctional nanoplatform for MRI and controlled drug delivery. [Copyright &y& Elsevier]

In this study, reduced graphene oxide (rGO)-wrapped dandelion-like CuO microspheres have been successfully synthesized using a one-step hydrothermal method without calcination. Characterization results demonstrate that dandelion-like CuO microspheres with sizes of 2.0 μm are well wrapped by ultrathin rGO nanosheets. Moreover, the introduced amount of GO dispersion in the reaction system was found to play a key role in tuning the phase compositions and microstructures of the resultant CuO-rGO composites. When used as electrode materials for supercapacitors, dandelion-like CuO wrapped by rGO nanosheets exhibited the best capacitive behavior with a specific capacitance of 296 F g −1 at 1.0 A g −1 and a retention of 96.1% after 2000 cycles at 2.0 A g −1 . Such excellent electrochemical performance might be mainly attributed to the rGO wrapping effect, efficiently providing higher electronic conductivity and buffering the volume changes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hollow CoSe 2 nanospheres are wrapped with flexible rGO nanosheets. • rGO on hollow CoSe 2 nanospheres reduces their aggregation and nanoparticle size. • OH– is more easily adsorbed at the CoSe 2 /rGO interface. • Hollow CoSe 2 /rGO electrodes exhibit enhanced rate capacities and cyclic stability. In this work, hollow CoSe 2 nanospheres wrapped with reduced graphene oxide (rGO) nanosheets are fabricated through combining the self-templated method with the electrostatic self-assembled method followed by heat treatment. The experimental results indicate that rGO nanosheets can act as space separator and structural protector to reduce the aggregation and nanoparticle size of hollow CoSe 2 nanospheres and meanwhile maintain their structural integrity. Density functional theory calculations indicate that the wrapping of rGO nanosheets not only increases the electrical conductivity but also reduces the adsorption energy of OH– at the CoSe 2 /rGO interface. Accordingly, hollow CoSe 2 /rGO nanocomposites yield specific capacities of 757C g−1 at 3 A/g and 552C g−1 at 20 A/g, as well as a capacity retention of 92 % over 5000 cycles at 10 A/g. When coupled with N -doped carbon nanotube-based negative electrode, the fabricated HSC device delivers an energy density of 50.1 W h kg−1 at 800 W kg−1 as well as maintains a capacity retention of 94 % after 5000 cycles. Our work offers a further understanding of the charge storage mechanism of hollow CoSe 2 /rGO nanocomposites and may be extended to develop other advanced nanostructured metal selenides/graphene electrodes. [ABSTRACT FROM AUTHOR]