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Boron neutron capture therapy (BNCT) is an encouraging therapeutic modality for cancer treatment. Prostate-specific membrane antigen (PSMA) is a cell membrane protein that is abundantly overexpressed in prostate cancer and can be targeted with radioligand therapies to stimulate clinical responses in patients. In principle, a spatially targeted neutron beam together with specifically targeted PSMA ligands could enable prostate cancer-targeted BNCT. Thus, we developed and tested PSMA-targeted poly(lactide

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 (tau), coercivity (Hc), and susceptibility (chi) 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, chi, and remanence (Mr). For example, life time of magnetic spin is directly related to the magnetic anisotropy energy (KuV) and also the size and volume of nanoparticles. The blocking temperature (Tb) changes from room temperature to 10 K as the size of cobalt nanoparticles is reduced from 13 to 2 nm. Similarly, H c is highly susceptible to the anisotropy of nanoparticles, while saturation magnetization is directly related to the canting effects of the disordered surface magnetic spins and follows a linear relationship upon plotting of ms (1/3) vs r(-1). Therefore, the nanoscaling laws of magnetic nanoparticles are important not only for understanding the behavior of existing materials but also for developing novel nanomaterials with superior properties. Since magnetic nanoparticles can be easily conjugated with biologically important constituents such as DNA, peptides, and antibodies, it is possible to construct versatile nano-bio hybrid particles, which simultaneously possess magnetic and biological functions for biomedical diagnostics and therapeutics. As demonstrated in this Account, nanoscaling laws for magnetic components are found to be critical to the design of optimized magnetic characteristics of hybrid nanoparticles and their enhanced applicability in the biomedical sciences including their utilizations as contrast enhancement agents for magnetic resonance imaging (MRI), ferromagnetic components for nano-bio hybrid structures, and translational vectors for magnetophoretic sensing of biological species. In particular, systematic modulation of saturation magnetization of nanoparticle probes is important to maximize MR contrast effects and magnetic separation of biological targets.

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

Successful development of ultra-sensitive molecular imaging nanoprobes for the detection of targeted biological objects is a challenging task. Although magnetic nanoprobes have the potential to perform such a role, the results from probes that are currently available have been far from optimal. Here we used artificial engineering approaches to develop innovative magnetic nanoprobes, through a process that involved the systematic evaluation of the magnetic spin, size and type of spinel metal ferrites. These magnetism-engineered iron oxide (MEIO) nanoprobes, when conjugated with antibodies, showed enhanced magnetic resonance imaging (MRI) sensitivity for the detection of cancer markers compared with probes currently available. Also, we successfully visualized small tumors implanted in a mouse. Such high-performance, nanotechnology-based molecular probes could enhance the ability to visualize other biological events critical to diagnostics and therapeutics.

Since inorganic nanocrystals exhibit unique shape-dependent nanoscale properties and can be utilized as basic building blocks for futuristic nanodevices, a systematic study on the shape control of these nanocrystals remains an important subject in materials and physical chemistry. In this feature article, we overview the recent progress on the synthetic development of symmetry-controlled colloidal nanocrystals of semiconductor and metal oxide, which are prepared through nonhydrolytic chemical routes. We describe their shape-guiding processes and illustrate the detailed key factors controlling their growth by examining various case studies of zero-dimensional spheres and cubes, one-dimensional rods, and quasi multidimensional structures such as disks, multipods, and stars. Specifically, the crystalline phase of nucleating seeds, surface energy, kinetic vs thermodynamic growth, and selective adhesion processes of capping ligands are found to be most crucial for the determination of the nanocrystal shape.

Precise control over interfacial chemistry between nanoparticles and other materials remains a significant challenge limiting the broad application of nanotechnology in biology. To address this challenge, we use “Steric Exclusion” to completely convert commercial quantum dots (QDs) into monovalent imaging probes by wrapping the QD with a functionalized oligonucleotide. We demonstrate the utility of these QDs as modular and non-perturbing imaging probes by tracking individual Notch receptors on live cells.

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.

Synthetic magnetic nanoparticles (MNPs) are emerging as versatile probes in biomedical applications, especially in the area of magnetic resonance imaging (MRI). Their size, which is comparable to biological functional units, and their unique magnetic properties allow their utilization as molecular imaging probes. Herein, we present an overview of recent breakthroughs in the development of new synthetic MNP probes with which the sensitive and target-specific observation of biological events at the molecular and cellular levels is possible.

The sections in this article are Introduction Magnetic Nanoparticle Contrast Agents Silica- or Dextran-coated Iron Oxide Contrast Agents Magnetoferritin Magnetodendrimers and Magnetoliposomes New Type of Contrast Agent: Non-hydrolytically Synthesized High Quality Iron Oxide Nanoparticles Iron Oxide Nanoparticles in Molecular MR Imaging Infarct and Inflammation Angiogenesis Apoptosis Gene Expression Cancer Imaging Summary and Outlook

Magnetic nanoparticles exhibit unique nanoscale properties and their utilization for various magnetic systems is of significant interest. Especially, heterostructured magnetic nanoparticles are emerging as next-generation materials due to their synergistically enhanced magnetism and potential multifunctionalities. Herein, we overview the recent advances in the development of magnetic nanoparticles with a focus on multicomponent heterostructured nanoparticles including alloys, core-shells, and binary superlattices synthesized via nonhydrolytic methods. Their multifunctionalites and high performance capabilities are demonstrated for applications in high density magnetic storages, chemical catalysis, and biomedical separation and diagnostics.

Magnetic nanoparticles exhibit unique nanoscale properties of superparamagnetism and have the potential to be utilized as excellent probes for magnetic resonance imaging (MRI). Especially, clinically benign iron oxide nanoparticles provide good MR probing capability and some of them are currently available for clinical applications. However, limited magnetic property and inability to escape from reticuloendothelial system (RES) of the currently used nanoparticles impede their further advancements and therefore it is necessary to develop advanced magnetic nanoparticle probes for next-generation molecular MR imaging. In this chapter, we overview recent progresses on the development of magnetic nanoparticle probes for molecular MR imaging. Utilization of these nanoparticle probes for both in vitro and in vivo molecular MR imaging will be described.

Inorganic nanocrystals with tailored geometries exhibit unique shape-dependent phenomena and subsequent utilization of them as building blocks for the fabrication of nanodevices is of significant interest. Herein, we review the recent developments in the shape control of colloidal nanocrystals with a focus on the scientifically and technologically important semiconductor and metal oxide nanocrystals obtained by nonhydrolytic synthetic methods. Many structurally unprecedented motifs have been discovered including polyhedrons, rods and wires, plates and prisms, and other advanced shapes such as branched rods, stars, inorganic dendrites, and dumbbells. The currently proposed shape-guiding mechanisms are presented and the important pioneering studies on the assembly of shape-controlled nanocrystals into ordered superlattices and the fabrication of prototype advanced nanodevices are discussed.

Spontaneous one dimensional arrangements of spherical Au nanoparticles were accomplished by using a liquid crystalline thiol ligand, 4′-(12-mercaptododecyloxy)biphenyl-4-carbonitrile. Simple thermal treatment of Au nanoparticles with the ligands showed 1D ordering of the Au nanoparticles.

Crystals consist of a periodic alternation of specific repeating molecules. The individual repeating molecules have quantized electronic structures while crystals have continuous electronic band structures that result from the overlap and combination of molecular orbitals of repeating molecules. Therefore, isolated molecules exhibit quantum mechanical properties, while the chemical and physical properties of bulk crystals obey the laws of classical mechanics. However, when the crystal size decreases into the nano-scale regime (1 ∼ 100 nm), the electronic band of the crystals starts to be quantized and the resulting nanocrystals behave as an intermediate between molecules and crystals.2, 3, 4, 5 These nanocrystals exhibit novel properties which differ from both molecular and bulk properties. For example, CdSe semiconductor crystals on the 10 nm scale, the characteristic red luminescence is no longer observed but the luminescence can be continuously tuned from red to blue by varying the crystal size. The melting temperature of nanocrystals simultaneously decreases when the nanocrystal size is reduced.6,7 In the nanoscopic world, crystal properties are highly dependent on the size, shape, and surface state of the crystals.

Our study describes a convenient one-step synthesis of ZnSe and ZnTe nanocrystals (NC) whose sizes and shapes are precisely tuned by varing the growth temperature or stabilizing surfactants. We utilized molecular precursors, bis(phenylselenolate or phenyltellurolato)zinc -N,N,N',N'-tetramethylethylenediamine (TMEDA), which effectively produce 0-dimensional sphere or 1-dimensional nanorods of ZnSe or ZnTe, respectively. Nanocrystals are highly monodispersed and luminescent; the emission wavelength varies over a wide range depending on the particle size. This study constitutes a nice demonstration of direct size and shape controlled synthesis of semiconductor nanocrystals and this method can be extended to the synthesis of nanocrystals of other materials.

A novel twinning-driven hyper-branching mechanism of 1-dimensional nanowires is demonstrated to provide a clear understanding of the growth behaviour of a complex nanocrystal structure. Specifically, we have discovered that the multiple twinning mechanism can be successfully applied to the hyper-branching of nanowires. Systematic variations of TiO2 hyper-branching in terms of branching multiplicity, branching angle, and size were observed, depending on the sequence, the degree, and the combination of two different twinning modes of contact and interpenetration. The twinning process is a reliable synthetic protocol for next generation nanostructures which require highly complex, but predictable shape and symmetry.

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.

A magnetic field is successfully utilized to induce the fabrication of size controllable one-dimensional (1-D) supercrystals which are composed of a highly crystalline assembly of fcc-packed cobalt nanoparticles; the anisotropy associated supercrystal magnetism is enhanced with four times higher coercivity than that of randomly aggregated nanoparticles.