The magnetism of electrospun porous high-entropy spinel oxides can be tuned by changing a single cation.

Graphene quantum dots (GQD), the new generation members of graphene-family, have shown promising applications in anticancer therapy. In this study, we report the synthesis of a fluorescent and biocompatible nanovector, based on GQD, for the targeted delivery of an anticancer drug with benzofuran structure (BFG) and bearing the targeting ligand riboflavin (RF, vitamin B2). The highly water-dispersible nanoparticles, synthesized from multi-walled carbon nanotubes (MWCNT) by prolonged acidic treatment, were linked covalently to the drug by means of a cleavable PEG linker while the targeting ligand RF was conjugated to the GQD by π–π interaction using a pyrene linker. The cytotoxic effect of the synthesized drug delivery system (DDS) GQD-PEG-BFG@Pyr-RF was tested on three cancer cell lines and this effect was compared with that exerted by the same nanovector lacking the RF ligand (GQD-PEG-BFG) or the anticancer drug (GQD@Pyr-RF). The results of biological tests underlined the low cytotoxicity of the GQD sample and the cytotoxic activity of the DDS against the investigated cancer cell lines with a higher or similar potency to that exerted by the BFG alone, thus opening new possibilities for the use of this drug or other anticancer agents endowed of cytotoxicity and serious side effects.

In the last few years, high-entropy oxides (HEOs), a new class of single-phase solid solution materials, have attracted growing interest in both academic research and industry for their great potential in a broad range of applications. This work investigates the possibility of producing pure single-phase HEOs with spinel structure (HESOs) under milder conditions (shorter heat treatments at lower temperatures) than standard solid-state techniques, thus reducing the environmental impact. For this purpose, a large set of HESOs was prepared via sol-gel and electrospinning (by using two different polymers). Ten different equimolar combinations of five metals were considered, and the influence of the synthesis method and conditions on the microstructure, morphology and crystalline phase purity of the produced HESOs was investigated by a combination of characterization techniques. On the other hand, the presence of specific metals, such as copper, lead to the formation of minority secondary phase(s). Finally, two representative pure single-phase HESOs were preliminarily evaluated as active anode materials in lithium-ion batteries and possible strategies to enhance their rate capability and cyclability were proposed and successfully implemented. The approaches introduced here can be extensively applied for the optimization of HEO properties targeting different applications.

We show, by accurate scattering calculations, that nanostructures obtained from thin films of J-aggregate dyes, despite their insulating behavior, are able to concentrate the electromagnetic field at optical frequencies like metallic nanoparticles. These results promise to widely enlarge the range of plasmonic materials, thus opening new perspectives in nanophotonics. Specifically we investigate ultrathin nanodisks and nanodisk dimers that can be obtained by standard nanolithography and nanopatterning techniques. These molecular aggregates display highly attractive nonlinear optical properties, which can be exploited for the realization of ultracompact devices for switching by light on the nanoscale without the need of additional nonlinear materials. W hen light interacts with metal nanoparticles and nanostructures, it can excite collective oscillations known as localized surface plasmons (LSPs), which provide the opportunity to confine light to very small dimensions below the diffraction limit. 1−4 This high confinement can lead to a striking near-field enhancement, which can significantly enhance weak nonlinear processes 5 and enables a great variety of applications such as optical sensing, 6,7 higher efficiency solar cells, 8 nanophotonics 1,5,9 including ultracompact lasers and amplifiers, 10 and antennas transmitting and receiving light signals at the nanoscale. 4,11,12 The small mode volume of LSP resonances also increases the photonic local density of states (LDOS) close to a plasmonic nanoparticle, enabling the modification of the optical properties (decay rate and quantum efficiency) of emitters placed in its close proximity (see for example ref 13 and Supporting Information Figure S1). The interaction of quantum emitters, as quantum dots or dye molecules, with individual metallic nanostructures carries significant potential for the quantum control of light at the nanoscale. 1,14−22 As first highlighted by Takahara et al., 23 only materials with a negative real part of the dielectric function and moderate losses are able to excite localized surface plasmons and hence to confine light to very small dimensions below the diffraction limit. These collective and confined excitations are efficiently supported, despite dissipative losses, by noble metals where the effective response of the electrons can be described by a Drude−Lorentz dielectric function whose real part is negative for frequencies below the plasma frequency. 2 Also superconductors or graphene has been proposed as a platform for surface plasmon polaritons. 24,25 Collective oscillations of free electrons are not the only way a negative permittivity may arise. It may also occur in the highenergy tail of a strong absorption resonance. For example, it has been shown that lattice vibrations in polar dielectric materials can also originate negative dielectric permittivity in the far-or mid-infrared spectral range, which can support phononpolaritons confined to the surface. 26,27 It has also been shown