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Well-defined recyclable Pd- and Rh-bipyridyl group-impregnated SBA-15 catalysts were prepared for C-C bond coupling reaction and selective hydrogenation reactions, respectively. These SBA-15 derived ligands for the catalysts were prepared by direct and indirect co-condensation method using bipyridyl-linked methallylsilane. This indirect method, involving methoxysilane generated from methallylsilane shows higher loading efficiency of transition metal catalysts on SBA-15 than the direct use of methallylsilane.

Nanoparticle clusters (NPCs) have attracted significant interest owing to their unique characteristics arising from their collective individual properties. Nonetheless, the construction of NPCs in a structurally well-defined and size-controllable manner remains a challenge. Here we demonstrate a strategy to construct size-controlled NPCs using the DNA-binding zinc finger (ZnF) protein. Biotinylated ZnF was conjugated to DNA templates with different lengths, followed by incubation with neutravidin-conjugated nanoparticles. The sequence specificity of ZnF and programmable DNA templates enabled a size-controlled construction of NPCs, resulting in a homogeneous size distribution. We demonstrated the utility of magnetic NPCs by showing a three-fold increase in the spin-spin relaxivity in MRI compared with Feridex. Furthermore, folate-conjugated magnetic NPCs exhibited a specific targeting ability for HeLa cells. The present approach can be applicable to other nanoparticles, finding wide applications in many areas such as disease diagnosis, imaging, and delivery of drugs and genes.

Ubergangsmetallchalkogenid(TMC)-Nanoflocken der Zusammensetzung MX2 (mit M=Ti, Zr und Hf; X=S und Se) kristallisieren bevorzugt in der Form gleichseitiger regelmasiger Sechsecke und weisen ein ausgepragtes Quanten-Confinement auf. Die hexagonale Form von oktaedrischen (1T) TMC-Nanoflocken ist das Ergebnis der Ladungslokalisierung an den Kanten und Ecken und der daraus resultierenden Coulomb-Abstosung. Grosenunabhangig haben alle Nanoflocken die Zusammensetzung MnX2n−2 und daher ein unoxidiertes Metallzentrum, was Dotierzustande hervorruft. Diese Zustande werden fur kleine Nanoflocken relevant und fuhren zu deren metallischen Charakter, aber fur grosere Nanoflocken (>6 nm) dominieren die Eigenschaften der 2D-Monolage. An die Kanten der Nanoflocken koordinierte Lewis-Basen haben keinen wesentlichen Einfluss auf die elektronische Struktur dieser Spezies und bestatigen die Nutzlichkeit der Kolloidsynthese.

Overcoming resistance: Heat-treated cancer cells possess a protective mechanism for resistance and survival. Resistance-free apoptosis-inducing magnetic nanoparticles (RAINs) successfully promote hyperthermic apoptosis, obstructing cell survival by triggering two functional units of heat generation and the release of geldanamycin (GM) for heat shock protein (Hsp) inhibition under an alternating magnetic field (AMF).

The intrinsic nature of small-molecule chemotherapeutics, including i) limited aqueous solubility, ii) systemic toxicity due to non-specific whole-body distribution, and iii) potential development of drug resistance after initial administration, compromises their treatment efficacy.[1] Recently, nanoparticle (NP)-based drug delivery systems have been considered as promising alternatives to overcome some of these limitations and begin to resolve obstacles in the disease management in clinical oncology.[2] The intraparticular space of a NP vector can be employed to package drug payloads without constrain associated with their solubility. Further, NP vectors exhibit enhanced permeability and retention (EPR) effects[3] that facilitate the differential uptake, leading to preferential spatio-distribution in tumor.[4] However, conventional NP drug delivery systems tend to passively release drug payloads, limiting the ability to release an effective drug concentration at a desired time window. Therefore, there is a need to develop next-generation NP drug delivery system such as a stimuli-responsive drug release system with a goal of achieving spatio-temporal control, by which an acute level of drug concentration can be delivered at the time point the NP vectors reach maximum tumor accumulation.[5] By doing so, it is expected to dramatically improve therapeutic effects in tumor and effectively reduce systematic toxicity at a minute drug dosage.[6]

Temperature control is an important method of self-defense in biological systems. For example, one response mounted by humans in an effort to fight injury, including viral and bacterial infections, involves an increase in body temperature, thus producing the well-recognized symptoms of fever.[1] Today, the idea of using artificial temperature control for disease removal is being realized with the aid of various techniques, such as ultrasound, near-infrared light, and magnetic field by increasing localized temperature in a targeted region.[2] Magnetic nanoparticles have attracted considerable attention for hyperthermia applications owing to their ability to generate heat effectively when exposed to an alternating magnetic field without a penetration depth limit.[3] Hyperthermia, the artificially induced heat treatment of a disease, uses temperatures ranging between 42 °C and 47°C. Generally, a temperature below 45 °C induces apoptotic cell death.[4] As compared to necrosis, apoptosis is a more benign form of “programmed” cell death.[5] Nonliving cells produced as the result of apoptotic process are cleaned by phagocytosis without affecting neighboring normal cells. In contrast, necrosis, typically generated by harsh and high-temperature hyperthermia, is considered relatively harmful because it can be correlated with inflammatory disease and metastasis.[6] However, achieving effective apoptotic hyperthermia is often difficult, as cells typically acquire resistance to induced thermal stress.[7] Repeated exposures to high temperatures with high concentration of magnetic nanoparticles are usually necessary to achieve a useful level of therapeutic efficacy even though the conditions could favor necrotic cell death rather than apoptosis. Because cancer cells are susceptible to heat at about 43 °C, while most normal tissues remain undamaged,[8] hyperthermia using this temperature defines a recognized but unmet goal.

Two-dimensional crystals, single sheets of layered materials, often show distinct properties desired for optoelectronic applications, such as larger and direct band gaps, valley- and spinorbit effects. Being atomically thin, the low amount of material is a bottleneck in photophysical and photochemical applications. Here, we propose the formation of stacks of two-dimensional crystals intercalated with small surfactant molecules. We show, using first principles calculations, that already the very short surfactant methyl amine electronically decouples the layers. We demonstrate the indirect-direct band gap transition characteristic for Group 6 transition metal dichalcogenides experimentally by observing the emergence of a strong photoluminescence signal for ethoxide-intercalated WSe2 and MoSe2 multilayered nanoparticles with lateral size of about 10 nm and beyond. The proposed hybrid materials offer the highest possible density of the two-dimensional crystals with electronic properties typical for monolayers. Variation of the surfactant's chemical potential allows fine-tuning of electronic properties and potentially elimination of trap states caused by defects.

Doped up: The incorporation of Zn(2+) dopants in tetrahedral sites leads to the successful magnetism tuning of spinel metal ferrite nanoparticles (see picture). (Zn(0.4)Mn(0.6))Fe(2)O(4) nanoparticles exhibit the highest magnetization value among the metal ferrite nanoparticles. Such high magnetism results in the largest MRI contrast effects (r2=860 mm(-1) s(-1)) reported to date and also huge hyperthermic effects.

Two-dimensional (2D) layered nanostructures have received increasing interest due to their unique nanoscale phenomena and their potential applications ranging from electronics and energy to catalysis. Recent investigation has revealed that laterally confined layered nanocrystals (LCLN) have remarkably enhanced electrochemical properties compared to their bulk counterparts owing to nanoscale characteristics that include large surface areas, finite lateral sizes, and enhanced open-edge morphologies. Among the variety of layered materials that have been described, tin sulfides are of particular interest because of their unique structural properties. SnS2 has a layered CdI2-type structure, composed of tin atoms sandwiched between two layers of hexagonally disposed closepacked sulfur atoms. The 2D layered characteristics of this substance are revealed in alkali metal intercalation phenomena, and by investigating anisotropy of properties such as electric and photoelectric conductivity. Owing to their large theoretical capacities for battery applications, bulk or micron sized tin-based materials have been extensively studied as possible alternatives for commercially available carbon electrodes. However, the main drawback of this system has been stemming from the large volume changes and accompanying sharp decrease in capacity that occur during electrochemical cycles. Aifantis et al. have reported that active sites with spherical and smaller volume fraction could improve electrochemical properties of anode materials from the view point of fracture mechanics. Other researchers also have reported that nanoscale tin sulfide-based materials would lead to an improvement in the cycling stability of these systems. Especially, layered SnS2 nanoplates with swelling tolerant hosting spaces and enhanced guest accessibility would provide enhanced diffusion for Li ion, and lead to the formation of Li-Sn alloy during the cycle, and improve the

Synthetische magnetische Nanopartikel (MNP) werden in der Biomedizin immer haufiger als Sonden eingesetzt. Dies gilt besonders fur die Anwendung in der Kernspintomographie (Magnetic Resonance Imaging, MRI). Diese Nanopartikel sind von ahnlicher Grose wie biologische Funktionseinheiten. Deshalb und wegen ihrer einzigartigen magnetischen Eigenschaften eignen sie sich zur molekularen Bildgebung. Dieser Aufsatz gibt einen Uberblick zu neuartigen MNP-Sonden, mit denen biologische Ereignisse auf molekularer und zellularer Ebene empfindlich und spezifisch nachgewiesen werden konnen.

nanosheetcrystalsfromthe tungsten oxide rods. The reaction between the carbondisulfide and hexadecylamine generates in situ hydrogendisulfideandhexadecylisothiocyanateviaN-hexadecyldithio-carbamate as a transient species [Eq.(1); see also Figures S1and S2 in the Supporting Information], and subsequent

Nanoparticles have the potential to revolutionize current bio-medical diagnostic and therapeutic methods. For example, magnetic nanoparticles with unique superparamagnetism are emerging as next-generation probes for high performance magnetic resonance (MR) imaging. Their enhanced properties and nanoscale controllability in terms of size, composition, surface states, and magnetic spin structure have allowed for the highly sensitive and target-specific MR imaging of various biological systems including cancer detection, cell trafficking, and angiogenesis. On the other hand, viruses can be utilized as excellent delivery vehicles due to their facile cellular transfection and gene expression efficacies within their target cells. Such excellent properties of viruses offer promising prospects for gene therapy of genetic diseases and cancers, as well as for the genetic engineering of cells. Despite these prospects, a lack of understanding of their biological behaviors including in vivo migration, molecular recognition, gene delivery, and ultimate fate following their desired biofunctional applications limits their further development. There have been previous studies in the development of nanoparticle probing systems for viruses including virus-gold and virus-quantum dot nanoparticle systems. However, their utilization in the probing of viral gene delivery has not been investigated so far. Recently, Gd-based MR contrast agent-coated viruses were developed, but their functional behaviors including targetrecognition, cellular transfection, and gene delivery capabilities have not been demonstrated partly due to the intrinsically low sensitivity of Gd-based MR contrast agents. Our strategy is to hybridize the virus with magnetic nanoparticles into a single nanoparticle system with the dual-functional capabilities of target-specific MR imaging and gene delivery. Specifically, we fabricate hybrid nanoparticles of “enhanced green fluorescent protein (eGFP) promoter genecontaining adenovirus” and “manganese-doped magnetism engineered iron oxide (abbreviated as MnMEIO) nanoparticle”. As the viral gene delivery vector, we selected adenoviruses. Adenoviruses are known to be highly effective for transferring double-stranded DNAs to various cell types. Along with a gene delivery capability, adenoviruses possess targetspecificity to the cells with overexpression of Coxsackievirus B adenovirus receptor (CAR) which is known to facilitate the binding and intrusion of adenoviruses to the host cells. As the magnetic nanoparticle component we selected manganese-doped magnetism-engineered iron oxide (MnFe2O4, MnMEIO) nanoparticles, since it is known that MnMEIO exhibits exceptional MR contrast effects (R2 (=1/T2) value of 358 sec mM) and therefore is advantageous as probes for ultra-sensitive MR imaging. Briefly, the thermal reaction of manganese chloride (MnCl2) and iron tris(2,4-pentadionate) in hot organic solvents containing oleic acid and oleylamine capping molecules yielded hydrophobically capped MnMEIO nanoparticles. Their water-solubility and biocompatibility were attained by introducing 2,3-dimercaptosuccinic acids to the nanoparticle surface. Nanoparticles obtained were 12 nm with a high sizemonodispersity (r < 7%) and possessed single crystallinity, and a saturation magnetization value of 110 emu g (Mn+Fe). Hybridization of adenoviruses with MnMEIO nanoparticles was performed through a slight modification of a literature method, as follows. First, the capsid lysine residues of the adenoviruses were converted to maleimide groups by reacting them with sulfo-succinimidyl(4-N-maleimidomethyl)cyclohexane-1-carboxylate (sulfo-SMCC) cross-linkers. These groups were allowed to react with a large stoichiometric amount of MnMEIO nanoparticles, which resulted in the formation of adenovirus-MnMEIO hybrid nanoparticles by way of the nucleophilic addition of a surface thiol group of MnMEIO to the C O M M U N IC A IO N

Anorganische Nanokristalle mit gezielt praparierten Formen und Abmessungen haben einzigartige, formabhangige Eigenschaften und sind als Bausteine zur Herstellung von Nanofunktionseinheiten von grosem Interesse. In diesem Aufsatz fassen wir die jungsten Entwicklungen bei der Formkontrolle von kolloidalen Nanokristallen zusammen, wobei der Schwerpunkt auf den wissenschaftlich und technologisch wichtigen Halbleiter- und Metalloxid-Nanokristallen liegt, die sich durch nichthydrolytische Synthesemethoden erhalten lassen. Viele ungewohnliche Strukturmotive wurden entdeckt, darunter Polyeder, Stabchen und Drahte, Scheiben und Prismen sowie komplexere Formen wie verzweigte Stabchen, Sterne, anorganische Dendrimere und Hanteln. Der gegenwartig favorisierte Mechanismus der Formkontrolle wird vorgestellt, ebenso wie richtungsweisende Studien zur Anordnung formkontrollierter Nanokristalle zu geordneten Ubergittern und zur Herstellung hochentwickelter Prototypen von Nanofunktionseinheiten.

The systematic shape control of colloidal nanocrystals including one-dimensional (1D) nanorods remains a key issue in the “bottom–up” approach of nanoscience. Here, we examine the anisotropic structural evolution of various semiconductor nanocrystals and systematically elucidate the key growth parameters for their shape control. The crystalline phase of nucleating seeds and kinetic growth regimes controlled by changing growth parameters are crucial for the determination of the 1D nanocrystal geometry.

Texaphyrins are pentaaza expanded porphyrins with the ability to form stable complexes with a variety of metal cations, particularly those of the lanthanide series. In biological milieus, texaphyrins act as redox mediators and mediate the production of reactive oxygen species (ROS). In this review, newer studies involving texaphyrin complexes targeting several different applications in anticancer therapy are described. In particular, the preparation of bismuth and lead texaphyrin complexes as potential α-core emitters for radiotherapy is detailed, as are gadolinium texaphyrin functionalized magnetic nanoparticles with features that make them of interest as dual-mode magnetic resonance imaging contrast agents and as constructs with anticancer activity mediated through ROS-induced sensitization and concurrent hyperthermia. Also discussed are gadolinium texaphyrin complexes as possible carrier systems for the targeted delivery of platinum payloads.

This review presents recent advances in synthetic methods and structural transformations of colloidal 2D layered metal chalcogenide nanocrystals. Planar 2D anisotropy and interlayer van der Waals gaps are the important characteristics of these nanocrystals for pristine disc, plate or sheet morphologies. These 2D nanocrystals undergo unique chemical transformations upon exposure to external chemical stimuli and newly obtained structures are 2D nanostructures with high complexity in their morphological geometries and chemical compositions. Finally, future opportunities and potential applications of 2D layered metal chalcogenide nanocrystals are briefly discussed.

ZnS thin films are made by laser driven chemical vapor deposition (CVD) from a single-source precursor, Zn(S{sub 2}COCHMe{sub 2}){sub 2} under vacuum conditions. Photofragments in the gas phase are identified simultaneously by luminescence spectroscopy. The laser selectively activates the initial decomposition of the precursor and drives its conversion to the desired materials under mild conditions. These photolytically produced films are compared to films made by thermal deposition from the same precursor. The deposits from both techniques, characterized by X-ray diffraction, Rutherford backscattering, and X-ray photoelectron spectroscopy, are pure stoichiometric ZnS in the hexagonal phase. Surface morphology differs in shape and granule size. During the laser-driven CVD process, gas-phase photochemical intermediates are identified by luminescence spectroscopy. The luminescent photoproducts are Zn and S{sub 2}, the two elemental components of the final material. Photofragmentation mechanisms leading to ZnS, the luminescent species Zn and S{sub 2}, and the gaseous organic byproducts are discussed. Further characterization of photofragmentation pathways is provided by the trapping of the photoreaction products and by mass spectroscopy. 34 refs., 6 figs.

This paper reports the facile photochemical synthesis of binary and ternary II/VI metal sulfides from single-source diethyl dithiocarbamate zinc and cadmium precursors, M(S{sub 2}-CNEt{sub 2}){sub 2}, M = Zn, Cd. Photoluminescence spectroscopy is used to simultaneously identify gas phase species present during the CVD process. This study demonstrates one of the first uses of light for both deposition and real time characterization of gas phase species in multiphase materials synthesis. It is demonstrated that ternary Zn{sub x}Cd{sub 1-x}S films as well as ZnS and CdS can be prepared photochemically under mild conditions and only in the area irradiated by the laser beam. Luminescence spectra show that the elements composing the films are produced in the gas phase. 20 refs., 2 figs., 1 tab.

Photolysis of M(NEt2)4 in the gas phase produces diatomic MN molecules (M = Ti, Zr, Hf). TiN and ZrN molecules were identified in the gas phase under CVD conditions by emission spectroscopy and time-of-flight mass spectroscopy. Nanostructured deposits of TiN were formed on quartz substrates by irradiating Ti(NEt2)4 gas at 355 nm. These studies demonstrate the gas phase formation of diatomic molecules having the same stoichiometry as that of the desired solid-phase deposit.

Current biomedical imaging techniques including magnetic resonance imaging (MRI), positron emission tomography (PET), and computed X-ray tomography (CT) are vital in the diagnosis of various diseases. Each imaging modality has its own merits and disadvantages, and a single technique does not possess all the required capabilities for comprehensive imaging. Therefore, multimodal imaging methods are quickly becoming important tools for state-of-the-art biomedical research and clinical diagnostics and therapeutics. In this Account, we will discuss synergistically integrated nanoparticle probes, which will be an essential tool in multimodal imaging technology. When inorganic nanoparticles are introduced into biological systems, their extremely small size and their exceptional physical and chemical properties make them useful probes for biological diagnostics. Nanoparticle probes can endow imaging techniques with enhanced signal sensitivity, better spatial resolution, and the ability to relay information about ...

Magnetic nanoparticles, which exhibit a variety of unique magnetic phenomena that are drastically different from those of their bulk counterparts, are garnering significant interest since these properties can be advantageous for utilization in a variety of applications ranging from storage media for magnetic memory devices to probes and vectors in the biomedical sciences. In this Account, we discuss the nanoscaling laws of magnetic nanoparticles including metals, metal ferrites, and metal alloys, while focusing on their size, shape, and composition effects. Their fundamental magnetic properties such as blocking temperature (Tb), spin life time (τ), coercivity (Hc), and susceptibility (χ) are strongly influenced by the nanoscaling laws, and as a result, these scaling relationships can be leveraged to control magnetism from the ferromagnetic to the superparamagnetic regimes. At the same time, they can be used in order to tune magnetic values including Hc, χ, and remanence (Mr). For example, life time of mag...

The inside cover displays multifunctional “adenovirus-magnet” nanoparticles possessing target-specific infection, magnetic resonance imaging (MRI), and gene expression capabilities. These hybrid nanoparticles, reported by Jin-Suck Suh, Jinwoo Cheon, and co-workers on p. 3109 in the Special Section on Bionanotechnology, selectively target the Coxsackievirus B adenovirus receptor (CAR)-positive cells and deliver the gene of enhanced green fluorescent protein (eGFP), while simultaneously being imaged by MRI. These hybrid nanoparticles can be regarded as new probes for in vivo MRI tracking of targeted viral gene delivery, which is essential for next-generation diagnostics and therapeutics.

Shape controlled synthesis of inorganic nanocrystals is one of the important issues in materials chemistry due to their novel shape dependent properties. Although various shapes of nanocrystals have been developed, a systematic account on the shape control of these nanocrystals still remains an important subject in materials chemistry. In this article, we will overview the recent developments in the geometrical shape evolution of semiconductor and metal oxide nanocrystals obtained by nonhydrolytic synthetic methods. Many structurally unprecedented motifs have appeared as zero-dimesional (D) polyhedrons, one-D rods and wires, two-D plates and prisms, and other advanced shapes such as branched rods, stars, and inorganic dendrites. Important parameters which determine the geometrical shapes of nanocrystals are also illustrated. In addition, as a possible application of such nanocrystals for biomedical sciences, we further describe their utilizations for cancer diagnosis through nanocrystal-assisted magnetic resonance imaging (MRI).

A simple one-pot synthesis of size and shape controlled ZnTe nanocrystals using a monomeric molecular precursor, [Zn(TePh)2][TMEDA], has been studied by varying the growth temperature or the templating surfactants.

Ordered arrays of palladium nanostructures have been obtained inside MCM-48 and SBA-15, using chemical vapor infiltration. Removal of the silica matrix affords porous three-dimensional Pd nanoballs and one-dimensional Pd nanowires, depending on the architecture of the silicate host.