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Magnetic–plasmonic nanoparticles (NPs) have shown remarkable potential in hyperthermia, magnetic resonance imaging, and surface-enhanced Raman scattering imaging and diagnostics. However, despite their promise, effective clinical translation remains limited due to a lack of fundamental knowledge about the biological response to these materials, and ongoing efforts seek to bridge the gap between nanomaterial design and effective applicability. To overcome these hurdles, the combination of inorganic NPs with lipid membranes has emerged as an attractive strategy for the biocompatibilization of nanomaterials, preserving the inherent properties of each component and exhibiting synergistic functionalities. This study explores the structural and dynamic aspects of magnetic–plasmonic liposomes produced via spontaneous self-assembly of Au–Fe3O4NPs and synthetic liposomes, as a function of the lipid vesicles' composition and concentration. By combining cryogenic electron microscopy, ultraviolet-visible spectroscopy, and dynamic light scattering, we demonstrated that the bending rigidity and fluidity of the lipid membrane control the aggregation of the NPs on the membrane and the colloidal stability of the hybrids. The experimental results demonstrate that the coexistence of 10 nm Fe3O4 magnetic seeds and 50 nm Au–Fe3O4NPs plays a crucial role in the assembly of lipid-NP magnetic–plasmonic hybrids. This thermodynamic control allows for fine adjustment of the hybrids' size and composition, thereby allowing for enhancement and tuning of the magnetic response. Overall, these results pave the way for the development of multifunctional nanomaterials with controlled magnetic–plasmonic properties, obtained via spontaneous self-assembly, as combined nanoprobes and nanovectors for potential applications in multimodal imaging and drug delivery. [ABSTRACT FROM AUTHOR]

Various methods, including X-ray diffraction and Raman and Mossbauer spectroscopy are used to study the topologically controlled composition of asymmetric binary nanocrystals (BNCs), comprising of a semiconductor Ti[O.sub.2] rodlike section and a magnetic gamma-[Fe.sub.2][O.sub.3] spherical domain. The analysis shows that such BNCs can find wide application in various fields of nanoscience, including photocatalysis, as well as nanocrystal assembly.

Synthesis of functionalized magnetic nanoparticles (NPs) for biomedical applications represents a current challenge. In this paper we present the synthesis and characterization of water-dispersible sugar-coated iron oxide NPs specifically designed as magnetic fluid hyperthermia heat mediators and negative contrast agents for magnetic resonance imaging. In particular, the influence of the inorganic core size was investigated. To this end, iron oxide NPs with average size in the range of 4-35 nm were prepared by thermal decomposition of molecular precursors and then coated with organic ligands bearing a phosphonate group on one side and rhamnose, mannose, or ribose moieties on the other side. In this way a strong anchorage of the organic ligand on the inorganic surface was simply realized by ligand exchange, due to covalent bonding between the Fe3+ atom and the phosphonate group. These synthesized nanoobjects can be fully dispersed in water forming colloids that are stable over very long periods. Mannose, ribose, and rhamnose were chosen to test the versatility of the method and also because these carbohydrates, in particular rhamnose, which is a substrate of skin lectin, confer targeting properties to the nanosystems. The magnetic, hyperthermal, and relaxometric properties of all the synthesized samples were investigated. Iron oxide NPs of ca. 16-18 nm were found to represent an efficient bifunctional targeting system for theranostic applications, as they have very good transverse relaxivity (three times larger than the best currently available commercial products) and large heat release upon application of radio frequency (RF) electromagnetic radiation with amplitude and frequency close to the human tolerance limit. The results have been rationalized on the basis of the magnetic properties of the investigated samples. [ABSTRACT FROM AUTHOR]

Asymmetric binary nanocrystals (BNCs), comprising one c-axis elongated anatase TiO2 section and one γ-Fe2O3 spherical domain attached together, are synthesized by heterogeneous nucleation of iron oxide onto the longitudinal facets of TiO2 nanorods in a ternary surfactant mixture. The topologically controlled composition of the BNCs is ascertained by a combination of powder X-ray diffraction, Raman and Mōssbauer spectroscopy, high-angle annular dark-field imaging, and high-resolution transmission electron microscopy lattice fringe mapping, while their size-dependent magnetic behavior is demonstrated by ac susceptibility measurements. The heteroepitaxial growth proceeds through a mechanism never observed before for colloidal nanoheterostructures: the two domains share a restricted and locally curved junction region, which accommodates efficiently the interfacial strain and retards the formation of misfit dislocations. It is believed that these BNCs, which combine the properties of two technologically relevant oxide materials, can pave the way to reinforced applications in several fields of nanoscience, such as in photocatalysis, in malignant cell treatments, and in nanocrystal assembly. [ABSTRACT FROM AUTHOR]

Here, we synthesize a Au@Fe 3 O 4 core@shell system with a highly uniform unprecedented star-like shell morphology with combined plasmonic and magnetic properties. An advanced electron microscopy characterization allows assessing the multifaceted nature of the Au core and its role in the growth of the peculiar epitaxial star-like shell with excellent crystallinity and homogeneity. Magnetometry and magneto-optical spectroscopy revealed a pure magnetite shell, with a superior saturation magnetization compared to similar Au@Fe 3 O 4 heterostructures reported in the literature, which is ascribed to the star-like morphology, as well as to the large thickness of the shell. Of note, Au@Fe 3 O 4 nanostar-loaded cancer cells displayed magneto-mechanical stress under a low frequency external alternating magnetic field (few tens of Hz). On the other hand, such a uniform, homogeneous, and thick magnetite shell enables the shift of the plasmonic resonance of the Au core to 640 nm, which is the largest red shift achievable in Au@Fe 3 O 4 homogeneous core@shell systems, prompting application in photothermal therapy and optical imaging in the first biologically transparent window. Preliminary experiments performing irradiation of a stable water suspension of the nanostar and Au@Fe 3 O 4 -loaded cancer cell culture suspension at 658 nm confirmed their optical response and their suitability for photothermal therapy. The outstanding features of the prepared system can be thus potentially exploited as a multifunctional platform for magnetic-plasmonic applications.

Magnetic nanoparticles, MNPs, mineralized within a human ferritin protein cage, HFt, can represent an appealing platform to realize smart therapeutic agents for cancer treatment by drug delivery and magnetic fluid hyperthermia, MFH. However, the constraint imposed by the inner diameter of the protein shell (ca. 8 nm) prevents its use as heat mediator in MFH when the MNPs comprise pure iron oxide. In this contribution, we demonstrate how this limitation can be overcome through the controlled doping of the core with small amount of Co(II). Highly monodisperse doped iron oxide NPs with average size of 7 nm are mineralized inside a genetically modified variant of HFt, carrying several copies of α-melanocyte-stimulating hormone peptide, which has already been demonstrated to have excellent targeting properties toward melanoma cells. HFt is also conjugated to poly(ethylene glycol) molecules to increase its in vivo stability. The investigation of hyperthermic properties of HFt-NPs shows that a Co doping of 5% is enough to strongly enhance the magnetic anisotropy and thus the hyperthermic efficiency with respect to the undoped sample. In vitro tests performed on B16 melanoma cell line demonstrate a strong reduction of the cell viability after treatment with Co doped HFt-NPs and exposure to the alternating magnetic field. Clear indications of an advanced stage of apoptotic process is also observed from immunocytochemistry analysis. The obtained data suggest this system represents a promising candidate for the development of a protein-based theranostic nanoplatform.

We demonstrate the fabrication of free-standing polymeric nanocomposite films, which present magnetic and electrically conductive anisotropic properties. Magnetically functionalized carbon nanofibers are dispersed in a polymeric solution and, upon casting under a weak external magnetic field, are easily oriented and permanently assembled in a head-to-tail orientation in the polymer film during solvent evaporation. Magnetic and conductive property studies reveal that the resulting films have a high degree of anisotropy in both cases, thus allowing their use in functional complex devices. As a proof of concept, we demonstrate the potential application of these films as flexible THz polarizers. The detailed study shows that very high attenuation values per unit film thickness and fiber mass concentration are achieved, paving thus the way for cost-effective fabrication of substrate-free systems that have advantage over conventional devices realized so far.

A novel and facile method for water dispersal of hydrophobic iron oxide nanoparticles based on the amphiphilic PAMAM-C12 dendrimer is described. Stable and highly concentrated water dispersions of multifunctional magnetic nanoparticles were obtained with this single-step approach, and showed interesting relaxometric properties for MRI applications. Importantly, this method does not require substitution of the native hydrophobic capping under nonmild reaction conditions, thus preserving the structural and magnetic properties of the nanoparticles, and extending the possibility of conjugation with thermally labile groups.

In this study, a new simple, fast, and inexpensive technique for the preparation of free-standing nanocomposite ultrathin films based on the conductive polymer poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and embedding iron oxide nanoparticles (NPs) is presented. These nanofilms were fabricated by a single step of spin-coated assisted deposition in conjunction with a release technique ("supporting layer technique") to detach them from the substrate. Free-standing nanofilms can be easily transferred onto several substrates due to their high conformability, preserving their functionalities. The effect of the addition of iron oxide nanoparticles on the structural and functional properties of the PEDOT:PSS nanofilms is investigated through topography, thickness, magnetic, magneto-optical activity, and conductivity characterizations. PEDOT:PSS and PEDOT:PSS/iron oxide NP nanofilms were tested as resistive humidity sensors. Their sensitivity to humidity was found to increase with increasing nanoparticle concentration. On the basis of these results, it is expected that these composites may furnish inexpensive and reliable means for relative humidity detection.

Asymmetric binary nanocrystals (BNCs) formed by a spherical γ-Fe(2)O(3) magnetic domain epitaxially grown onto a lateral facet of a rodlike anatase TiO(2) nanorod have been functionalized with PEG-terminated phospholipids, resulting in a micellar system that enables the BNC dispersion in aqueous solution. The further processability of the obtained water-soluble BNC including PEG lipid micelles and their use in bioconjugation experiments has been successfully demonstrated by covalently binding to bovine serum albumin (BSA). The whole process has also been preliminarily performed on spherical iron oxide nanocrystals (NCs) and TiO(2) nanorods (NRs), which form single structural units in the heterostructures. Each step has been thoroughly monitored by using optical, structural, and electrophoretic techniques. In addition, an investigation of the magnetic behavior of the iron oxide NCs and BNCs, before and after incorporation into PEG lipid micelles and subsequently bioconjugation, has been carried out, revealing that the magnetic characteristics are mostly retained. The proposed approach to achieving water-soluble anisotropic BNCs and their bioconjugates has a large potential in catalysis and biomedicine and offers key functional building blocks for biosensor applications.

We present a simple technique for magnetic-field-induced formation, assembling, and positioning of magnetic nanowires in a polymer film. Starting from a polymer/iron oxide nanoparticle casted solution that is allowed to dry along with the application of a weak magnetic field, nanocomposite films incorporating aligned nanocrystal-built nanowire arrays are obtained. The control of the dimensions of the nanowires and of their localization across the polymer matrix is achieved by varying the duration of the applied magnetic field, in combination with the evaporation dynamics. These multifunctional anisotropic free-standing nanocomposite films, which demonstrate high magnetic anisotropy, can be used in a wide field of technological applications, ranging from sensors to microfluidics and magnetic devices.

Water-soluble biocompatible rhamnose-coated Fe(3)O(4) nanoparticles of 4.0 nm are obtained by covalent anchorage of rhamnose on the nanoparticles surface via a phosphate linker. These nanoparticles present superparamagnetic behavior and nuclear relaxivities in the same order of magnitude as Endorem that make them potential magnetic resonance imaging (MRI) contrast agents of a second generation, where the saccharides represent also specific ligands able to target lectins on skin cells.