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High-quality Zn(x)Cd(1-x)Se nanocrystals have been successfully prepared at high temperature by incorporating stoichiometric amounts of Zn and Se into pre-prepared CdSe nanocrystals. With increasing Zn content, a composition-tunable emission across most of the visible spectrum has been demonstrated by a systematic blue-shift in emission wavelength. The photoluminescence (PL) properties for the obtained Zn(x)Cd(1-x)Se nanocrystals (PL efficiency of 70-85%, fwhm = 22-30 nm) are comparable to those for the best reported CdSe-based QDs. In particular, they also have good PL properties in the blue spectral range. Moreover, the alloy nanocrystals can retain their high luminescence (PL efficiency of over 40%) when dispersed in aqueous solutions and maintain a symmetric peak shape and spectral position under rigorous experimental conditions. A rapid alloying process was observed at a temperature higher than "alloying point". The mechanism of the high luminescence efficiency and stability of Zn(x)Cd(1-x)Se nanocrystals is explored.

A separate two-step process with a rapid nucleation and a subsequent template-directed growth has been employed to synthesize uniform Ag nanoparticles, which avoids a classical un-refrained ripening process resulting in a wide size distribution. Some silver nanocrystallites prepared by this approach are particularly interesting because of their unusual nanostructures with multiple nanostripes caused by stacking faults.

A promising photocatalytic system in the form of heterostructured nanocrystals (HNCs) is presented wherein alloyed ZnS-CuInS2 (ZCIS) semiconductor nanorods are decorated with Pt and Pd4 S nanoparticles. This is apparently the first report on the colloidal preparation and photocatalytic behavior of ZCIS-Pt and ZCIS-Pd4 S nanoscale heterostructures. Incorporation of Pt and Pd4 S cocatalysts leads to considerable enhancement of the photocatalytic activity of ZCIS for visible-light-driven hydrogen production.

The orthorhombic polymorph of Cu2ZnGeS4 (CZGS) is a metastable wurtzite-derived phase that can only be prepared in the bulk form by extensive heating at high temperatures (≥790 °C) when using the conventional solid-state reaction route. By employing a facile solution-based synthetic strategy, we were able to obtain phase-pure orthorhombic CZGS in nanocrystalline form at a much lower reaction temperature. Prior to this work, the colloidal synthesis of single-phase orthorhombic CZGS on the nanoscale has never been reported. We find that the use of an appropriate combination of coordinating solvents and precursors is crucial to the sole formation of this metastable phase in solution. A possible formation mechanism is proposed on the basis of our experimental results. Because CZGS consists of environmentally benign metal components, it is regarded as a promising alternative material to the technologically useful yet toxic cadmium-containing semiconductors. The orthorhombic CZGS nanocrystals display strong photon absorption in the visible spectrum and are photocatalytically active in dye degradation under visible-light illumination.

In the nanoscience and nanotechnology, the study of nanocrystal self-assembly has been regarded as a key technology in leading future industrial development. The colloidal self-assembly techniques, particularly for one-dimensional (1D) building blocks, have been widely adopted for the systematic fabrication of functional nanocrystals and received an extensive research attention. However, the increase in the building blocks’ anisotropy, e.g. from sphere to rod/wire, has dramatically leveled up the difficulty in organizing them into ordered structures. To realize tailored 1D nanocrystal self-assembled structures, a profound understanding and detailed design of self-assembly mechanism and procedures are much needed. Here, a thorough review over 1D nanocrystal self-assembly methods and alignments are present to achieve large-scale functional structures. Through different techniques, such as evaporation, template, electric field, Langmuir-Blodgett film and chemical bonding, nanocrystals with various shapes can be self-assembled on substrates, at interfaces and in solutions. These assembled structures that have been achieved so far, can exhibit different degrees of alignments, such as stripe pattern as non-close-packed structure, horizontal, vertical alignments as close-packed monolayers, nematic, semectic alignments, AB stacking of vertical alignments, three-dimensional (3D) assembly as close-packed multilayers. In general, these self-assembly techniques can reach much small dimension and create microstructures that possess unique properties different from their individual building blocks.

Graphitic carbon nitride (g-C3N4), which typically acts as the 2D support for loading with cocatalysts, endows fascinating performances for photocatalytic water splitting. Benefiting from the natural sheet-like structure in g-C3N4, 1D metal phosphides (Co2P) nanorods are incorporated into 2D porous g-C3N4 nanosheets via a solution-phase method under ultrasonication. The novel 1D/2D Co2P/g-C3N4 heterojunction nanohybrids exhibit ameliorated visible-light photocatalytic H2 generation without the assistance of Pt as noble metal cocatalysts. Interestingly, the optimal loading of Co2P nanorods is 3 wt%, giving a maximum H2 production rate of 53.3 µmol h−1 g−1. Hence, the solution-phase hybridization technique can be extensively applied for the smart engineering of other 1D and 2D nanomaterials, leading to unprecedented opportunities on the highly efficient heterojunction photocatalysts for solar-to-H2 conversion.

Recent advances in nanomaterials have produced a new class of fluorescent labels by conjugating semiconductor quantum dots with biorecognition molecules. These nanometer-sized conjugates are water-soluble and biocompatible, and provide important advantages over organic dyes and lanthanide probes. In particular, the emission wavelength of quantum-dot nanocrystals can be continuously tuned by changing the particle size, and a single light source can be used for simultaneous excitation of all different-sized dots. High-quality dots are also highly stable against photobleaching and have narrow, symmetric emission spectra. These novel optical properties render quantum dots ideal fluorophores for ultrasensitive, multicolor, and multiplexing applications in molecular biotechnology and bioengineering.

The molecular processes of drugs from cellular uptake to intracellular distribution as well as the intracellular interaction with the target molecule are critically important for the development of new antitumor drugs. In this work, we have successfully developed a label-free surface-enhanced Raman scattering (SERS) technique to monitor and visualize the metabolism of antitumor drug 6-mercaptopurine in living cells. It has been clearly demonstrated that Au@Ag NPs exhibit an excellent Raman enhancement effect to both 6-mercaptopurine and its metabolic product 6-mercaptopurine-ribose. Their different ways to absorb at the surface of Au@Ag NPs lead to the obvious spectral difference for distinguishing the antitumor drug and its metabolite by SERS spectra. The Au@Ag NPs can easily pass through cell membranes in a large amount and sensitively respond to the biological conversion of 6-mercaptopurine in tumor cells. The Raman imaging can visualize the real-time distribution of 6-mercaptopurine and its biotransformation with the concentrations in tumor cells. The SERS-based method reported here is simple and efficient for the assessments of drug efficacy and the understanding of the molecular therapeutic mechanism of antitumor drugs at the cellular level.

Colloidal orthorhombic AgGaS2 nanocrystals are synthesized from a mixture of Ag(S2CNEt2) and Ga(S2CNEt2)3 and a coordinating solvent such as dodecanethiol, hexadecanethiol, oleylamine, and hexadecylamine (Ar, 280 °C, 2 h).

Various polymeric nanoparticles have been extensively engineered for applications in controlled drug release delivery in the last decades. Currently, there is a great demand to develop a strategy to qualitatively and quantitatively evaluate these polymeric nanoparticle formulations for producing innovative delivery systems. In this work, a screening platform is developed using luminescent quantum dots as drug model and imaging label to evaluate nanoparticle formulations incorporating either hydrophilic or hydrophobic drugs and imaging agents. It is validated that there is no influence of the incorporated entities on the cellular uptake profile. The use of quantum dots enables efficient detection and precise quantitation of cellular uptake of particles which occupy 25% of the cell volume. The correlation of quantum dot- and doxorubicin-incorporated nanoparticles is useful to develop an evaluation platform for nanoparticle formulations through imaging and quantitation. This platform is also used to observe the surface properties effect of other polymers such as chitosan and poly(ethylene) glycol on the cellular interaction and uptake. Moreover, quantum dots can be used to study microparticle theranostic delivery formulations by deliberately incorporating as visible ring surrounding the microparticles for their easy identifying and tracing in diagnostic and chemotherapeutic applications.

Factors secreted by primary tumors can alter the microenvironment at distant organ sites, generating pre-metastatic niches for subsequent metastatic cancer cell colonization. Breast cancer cells have a propensity to home preferentially to the lung, but the underlying molecular mechanisms whereby primary breast carcinoma-derived factors affect the pre-metastatic lung environment before the arrival of the tumor cells are poorly understood. In this study, 4T1 mammary carcinoma cells were subcutaneously injected into the mammary glands of mice, resulting in the induction of inflammation, increased total vessel density and recruitment of bone marrow-derived cells (BMDCs) in pre-metastatic lungs. Subsequent examination revealed that the sites of inflammatory cell clusters in the lungs were tumor metastasis sites. Moreover, vascular endothelial growth factor (VEGF) induced prostaglandin E2 (PGE2) production in mouse pulmonary microvascular endothelial cells (MPVECs) and enhanced the adhesion of 4T1 cells. Treatment with the cyclooxygenase-2 inhibitor celecoxib significantly reduced 4T1 cell adhesion to MPVECs, and also reduced cancer metastasis and the inflammatory response. These results suggest that VEGF may be an underlying carcinoma-derived factor responsible for formation of the pre-metastatic niche in the lung of 4T1 cell-bearing mice. This study, therefore, demonstrated that primary tumors can alter the lung microenvironment during the pre-metastatic phase by triggering an inflammatory response and PGE2 production. Primary tumor-derived VEGF might thus be a crucial factor responsible for the formation of the pre-metastatic niche by inducing PGE2 production.

Graphene oxide has widely been employed in various fields, but its structure and composition has still not been fully understood. Here we report that freshly prepared graphene oxide exhibits a large number of π-conjugated carbon radicals at its π-network plane, which result from the addition reaction of hydroxyl radicals from H2O2 onto the conjugated double bonds of graphene oxide. The π-conjugated carbon radicals can directly initiate the long-lasting visible chemiluminescence of luminol, which is even stronger than that obtained when horseradish peroxidase and H2O2 are used. Previously, graphene oxide was mainly reported to be a quencher of chemiluminescence instead. Remarkably, the reacted radicals can be regenerated, thereby enabling the repetitive initiation of chemiluminescence by re-treatment of graphene oxide. The results reported here provide a new understanding of the structure, properties, and applications of graphene oxide.

We have developed a selective upconversion switching method for the ratiometric fluorescence detection of nitrite using upconversion nanoparticles (UCNPs) and an efficient nitrite reaction. The green emission (λ(em) = 539 nm) of NaYF4:Yb(3+),Er(3+) nanoparticles can be selectively quenched by the neutral red (NR) dye due to the spectral overlap between the emission at 539 nm and the absorption of NR, while its red emission (λ(em) = 654 nm) remains unchanged. Nitrite reacts specifically and strongly with NR to form diazonium salt and lose the diazonium group, which sharply decreases the absorption of NR. Thus, the green emission of NaYF4:Yb(3+),Er(3+) can be recovered by increasing the amount of nitrite, leading to visible color changes from red to orange-yellow and finally green under excitation at 980 nm. The increase in the ratio of emission intensities (I539/I654) is quantitatively correlated to the concentration of nitrite ions. Moreover, the developed method has been successfully applied to nitrite detection in real samples such as drinking water, natural water and meat foods. In particular, the upconversion sensors can efficiently avoid background optical interference and thus show potential for the detection of nitrite salts in complex samples.

The ability of nanoscopic materials to self-organize into large-scale assembly structures that exhibit unique collective properties has opened up new and exciting opportunities in the field of nanotechnology. Although earlier work on nanoscale self-assembly has focused on colloidal spherical nanocrystals as building blocks, there has been significant interest in recent years in the self-assembly of colloidal nanocrystals having well-defined facets or anisotropic shapes. In this review, particular attention is drawn to anisotropic one-dimensional (1D) nanocrystals, notably nanorods and nanowires, which can be arranged into a multitude of higher-order assembly structures. Different strategies have been developed to realize self-assembly of colloidal 1D nanocrystals and these are highlighted in the first part of this review. Self-assembly can take place (1) on substrates through evaporation control, external field facilitation and template use; (2) at interfaces, such as the liquid–liquid and the gas–liquid interface; and (3) in solutions via chemical bonding, depletion attraction forces and linker-mediated interactions. The choice of a self-assembly approach is pivotal to achieving the desired assembly configuration with properties that can be exploited for functional device applications. In the subsequent sections, the various assembly structures that have been created through 1D nanocrystal self-assembly are presented. These organized structures are broadly categorized into non-close-packed and close-packed configurations, and are further classified based on the different types of 1D nanocrystal alignment (side-by-side and end-to-end), orientation (horizontal and vertical) and ordering (nematic and smectic), and depending on the dimensionality of the structure (2D and 3D). The conditions under which different types of arrangements are achieved are also discussed.

An effective separation process is developed to remove free protein from the protein-protected gold clusters via co-precipitation with zinc hydroxide on their surface. After dialysis, the purified clusters exhibit an enhanced fluorescence for improved sensitive detection and selective visualization.

Huisgen 1,3-dipolar cycloaddition “click” reaction with functional quantum dots and magnetic nanoparticles in water is presented. The introduction of “click” enabling groups on the surface of the nanoparticles is combined into one step with a transfer into water process. Reaction between acetylene and azide groups is used for the fabrication of covalent spherical assemblies in solution.

In this paper, we report a simple and clean method of producing uniform nonaqueous gold colloids by the chemical reduction of chloroauric acid (HAuCl4) using the oxygen-free organic supporting medium formamide itself as reducing agent in the presence of the stabilizer poly(vinylpyrrolidone) (PVP). The reduction of HAuCl4 can take place easily at room temperature in the new reducing system without introducing foreign reducing agents. A two-step reaction process to gold particles was suggested from the kinetics analysis for the formation of gold colloids in formamide systems. The difference in the production of gold particles in formamide solution from the established route in aqueous solution was also depicted. This new and effective chemical route also provides an alternative method to produce other uniform transition-metal particles in nonaqueous solvents.

A clear Coulomb staircase has been observed by using scanning tunneling microscopy in a new nanostructure with a surface-capped tunneling layer on the gold particle instead of a conventional tunneling thin film between the gold particle and substrate electrode. The occurrence of the Coulomb staircase was due to the pure and uniform surface-capped gold particles prepared by an efficient photochemical formation in a new kind of reducing nonaqueous system. As a comparison, the phenomenon cannot take place in the same nanostructure as above with the gold particle prepared by photochemical reduction in aqueous solution or typical chemical reduction.

A modified inverse microemulsion technique was used to synthesize coated Ag2S/CdS nanocomposites of ∼10 nm in diameter. Their nonlinear absorption was observed with picosecond and nanosecond laser radiation of 532-nm wavelength. The nonlinear absorption in the Ag2S/CdS nanocomposites was enhanced, in comparison with the CdS nanoparticles, due to free-carrier absorption. In addition, the relaxation times of photoexcited free carriers in the Ag2S/CdS nanocomposites were also determined to be a few nanoseconds.

Inflammation is a potent promoter of tumor metastasis. The aim of the present study was to explore the function of systemic inflammation in the formation of lung metastasis of breast cancer cells in a mouse model. BALB/c mice were injected intraperitoneally with lipopolysaccharide (LPS) in order to establish an inflammatory animal model and 4T1 murine breast cancer cells were injected through the tail vein to induce lung metastasis. The levels of proinflammatory cytokines were evaluated by ELISA. Metastases on the surface of the lungs were counted and histologically analyzed by hematoxylin and eosin staining. Angiogenesis in the lungs was examined by CD31 immunofluorescence. Mouse pulmonary endothelial cells (MPVECs) were isolated and used to assay endothelial tube formation and determine the protein expression levels of vascular endothelial growth factor (VEGF) in vitro. Serum levels of VEGF and prostaglandin E2 (PGE2), the number and size of metastatic lesions, and the expression levels of cyclooxygenase‑2 were significantly greater in the lungs of LPS‑treated mice, as compared with those in control mice threated with phosphate‑buffered saline. Blood vessel density was also markedly increased in the LPS‑treated mice. These increases were reversed by treatment with celecoxib. In vitro, the protein expression levels of VEGF produced by the PGE2‑treated cells were significantly increased in a concentration‑dependent manner. In addition, the production of VEGF was increased in response to treatment with the PGE2 receptor (EP2) agonist ONO‑AE1‑259‑01; however, this increase was abrogated by treatment with AH6809, an EP2 receptor antagonist. Treatment with PGE2 or VEGF alone promoted the tube formation of MPVECs and this effect was reversed by treatment with celecoxib. These results demonstrated that PGE2 may regulate the release of VEGF by MPVECs through the EP2 receptor pathway and thereby promoted pulmonary angiogenesis and breast cancer metastasis in a mouse model.

The ability of nanoscopic materials to self-organize into large-scale assembly structures that exhibit unique collective properties has opened up new and exciting opportunities in the field of nanotechnology. Although earlier work on nanoscale self-assembly has focused on colloidal spherical nanocrystals as building blocks, there has been significant interest in recent years in the self-assembly of colloidal nanocrystals having well-defined facets or anisotropic shapes. In this review, particular attention is drawn to anisotropic one-dimensional (1D) nanocrystals, notably nanorods and nanowires, which can be arranged into a multitude of higher-order assembly structures. Different strategies have been developed to realize self-assembly of colloidal 1D nanocrystals and these are highlighted in the first part of this review. Self-assembly can take place (1) on substrates through evaporation control, external field facilitation and template use; (2) at interfaces, such as the liquid–liquid and the gas–liquid interface; and (3) in solutions via chemical bonding, depletion attraction forces and linker-mediated interactions. The choice of a self-assembly approach is pivotal to achieving the desired assembly configuration with properties that can be exploited for functional device applications. In the subsequent sections, the various assembly structures that have been created through 1D nanocrystal self-assembly are presented. These organized structures are broadly categorized into non-close-packed and close-packed configurations, and are further classified based on the different types of 1D nanocrystal alignment (side-by-side and end-to-end), orientation (horizontal and vertical) and ordering (nematic and smectic), and depending on the dimensionality of the structure (2D and 3D). The conditions under which different types of arrangements are achieved are also discussed.

A new "turn on" fluorescence nanosensor for selective Hg(2+) determination is reported based on bis(dithiocarbamato)copper(II) functionalized carbon nanodots (CuDTC2-CDs). The CuDTC2 complex was conjugated to the prepared amine-coated CDs by the condensation of carbon disulfide onto the nitrogen atoms in the surface amine groups, followed by the coordination of copper(II) to the resulting dithiocarbamate groups (DTC) and finally by the additional coordination of ammonium N-(dithicarbaxy) sarcosine (DTCS) to form the CuDTC2-complexing CDs. The CuDTC2 complex at surface strongly quenched the bright-blue fluorescence of the CDs by a combination of electron transfer and energy transfer mechanism. Hg(2+) could immediately switch on the fluorescence of the CuDTC2-CDs by promptly displacing the Cu(2+) in the CuDTC2 complex and thus shutting down the energy transfer pathway, in which the sensitive limit for Hg(2+) as low as 4 ppb was reached. Moreover, a paper-based sensor has been fabricated by printing the CuDTC2-CDs probe ink on a piece of cellulose acetate paper using a commercial inkjet printer. The fluorescence "turn on" on the paper provided the most conveniently visual detection of aqueous Hg(2+) ions by the observation with naked eye. The very simple and effective strategy reported here facilitates the development of portable and reliable fluorescence nanosensors for the determination of Hg(2+) in real samples.

In this paper the anomalous optical responses and structural variations of Fe 2 O 3 nanoparticles coated with a layer of stearates are correlated. These variations are originated from the quantum confined polaronic state evidenced by spectroscopic characteristics, which is the interplay of the quantum size effect, interfacial effect introduced by stearates and localized d electrons in the Fe 2 O 3 nanoparticles.

A reversible and reproducible bistable electrical memory switching phenomenon was observed in an asymmetrical sandwich structure with coherent electrodeposited amorphous thin films between Al and indium tin oxide electrodes based on a new type of molecular semiconductor (NCTA) 2 Ni(DMIT) 2 . It can be achieved between a high-impedance OFF state and a low-impedance ON state simply by changing the polarity of an applied electric field across the device. The electrical memory switching process is described in detail, and a plausible microscopic switching mechanism is proposed based on the formation and deformation of mixed-valence semiconductor through electric field-induced solid-state redox reaction resulting from a negative fractional charge withdrawing and injecting process.

International audience; Fabrication and synthesis of plasmonic structures is rapidly moving towards sub-nanometer accuracy incontrol over shape and inter-particle distance. This holds the promise for developing device componentsbased on novel, non-classical electro-optical effects. Monochromated electron energy-loss spectroscopy(EELS) has in recent years demonstrated its value as a qualitative experimental technique in nano-optics andplasmonic due to its unprecedented spatial resolution. Here, we demonstrate that EELS can also be usedquantitatively, to probe surface plasmon kinetics and damping in single nanostructures. Using thisapproach, we present from a large (.50) series of individual gold nanoparticles the plasmon Quality factorsand the plasmon Dephasing times, as a function of energy/frequency. It is shown that the measured generaltrend applies to regular particle shapes (rods, spheres) as well as irregular shapes (dendritic, branchedmorphologies). The combination of direct sub-nanometer imaging with EELS-based plasmon dampinganalysis launches quantitative nanoplasmonics research into the sub-nanometer realm.

The pathogenesis of gastric cancer is not completely understood. Tumor necrosis factor-α-induced protein-8 like-2 (TIPE2) has recently been identified as a novel negative regulator gene of the immune system, and studies in mice and humans have suggested its inhibitory action in both inflammation and cancer. In this study, we examined the expression levels of TIPE2 in human gastric cancer tissues and also samples of paraneoplastic control tissue, and found that TIPE2 expression was reduced in gastric cancer. To investigate the role of TIPE2 in gastric cell carcinogenesis, a TIPE2 plasmid was introduced into gastric cell lines and TIPE2 function was examined. Colony-forming assays showed that restoration of TIPE2 expression in gastric cells significantly suppressed cell proliferation. Analysis by flow cytometry showed that the number of cells in the S phase of the cell cycle was reduced concomitant with TIPE2 expression, and cell apoptosis was maintained at a low level. Microarray and western blot analyses revealed that TIPE2 selectively up-regulated N-ras and p27 expression. The role of p27 in mediating TIPE2-associated cell growth inhibition was verified by a p27 siRNA interference assay. In this study, we proved that TIPE2 is an inhibitor of gastric cancer cell growth, and suggest that TIPE2 might promote a p27-associated signaling cascade that leads to restored control of the cell cycle and cell division. Our results provide a new molecular mechanism by which TIPE2 may regulate proliferation of gastric cells.

In fabricating materials at the nanometer scale, nanotechnologists typically employ two general strategies: bottom-up and top-down. While the bottom-up approach constructs nanomaterials from basic building blocks like atoms or molecules, the top-down approach produces nanostructures by deconstructing larger materials with the use of lithographic tools (i.e., physical top-down) or through chemical-based processes (i.e., chemical top-down). This tutorial review summarizes the various top-down nanofabrication methods, with great emphasis on the chemical routes that can generate nanoporous materials and ordered arrays of nanostructures with three-dimensional features. The chemical top-down routes that are discussed in detail include (1) templated etching, (2) selective dealloying, (3) anisotropic dissolution, and (4) thermal decomposition. These emerging nanofabrication tools open up new avenues in the creation of functional nanostructures with a wide array of promising applications.

Two C 60 derivatives, dodecylaminofullerene (DAF) and multihydroxydodecylaminofullerene (MHDAF) were prepared. The isotherms showed that the limiting molecular areas of DAF and MHDAF are around 60 A 2 and 64.7 A 2 respectively, which suggests that the aggregations of the molecules at the air-water interface are decreased compared with that of C 60 . The best transfer ratio could be enhanced to 0.7–1 by using the vertical dipping method. The structural characteristics of DAF Langmuir-Blodgett (LB) films were studied by UV-Vis spectroscopy, atomic force microscopy and transmission electron microscopy. The second-order susceptibility χ (2) and molecular hyperpolarizability (β) of 12-layer LB films of DAF are determined to be 3.26 × 10 −6 esu and 1.46 × 10 −28 esu respectively.

The organic molecule with a nitroxyl free radical and hydrophobic alkyl chain, 2-(4-(hexadecyloxy) phenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazolyl-1-oxyl 3- N -oxide (HTDIOO), was designed and synthesized. Under suitable conditions, the stable monolayer of this compound formed at the air-water interface could be successfully transferred onto various substrates by the Langmuir-Blodgett (LB) method. The structural characteristics of the LB films were studied by atomic force microscopy, Fourier transform IR spectroscopy, electron spin resonance and small-angle X-ray diffraction techniques. Using magnetic force microscopy, we have observed a quasi-one-dimensional band structure composed of magnetic domains in the local regions of HTDIOO LB films.

Multifunctional polymeric nano- and microparticles are engineered as theranostic carriers and their selective size-dependent cellular uptake is demonstrated. It is found that effective uptake and accumulation of nanoparticles occurs in both normal and cancer cells, whereas, that of microparticles occurs in cancer cells but not in normal cells, allowing cancer cells to be specifically targeted for local drug delivery.

The chemical sensing for the convenient detection of mercuric ion (II) (Hg(2+)) have been widely explored with the use of various sensing materials and techniques. It still remains a challenge to achieve ultrasensitive but simple, rapid, and inexpensive detection to metal ions. Here we report a surface-enhanced Raman scattering (SERS) chip for the femtomolar (fM) detection of Hg(2+) by employing silver-coated gold nanoparticles (Au@Ag NPs) together with an organic ligand. 4,4'-Dipyridyl (Dpy) can control the aggregation of Au@Ag NPs via its dual interacting sites to Ag nanoshells to generate strong Raman hot spots and SERS readouts. However, the presence of Hg(2+) can inhibit the aggregation of Au@Ag NPs by the coordination with Dpy, and as a result the SERS signals of Dpy are quenched. On the basis of these findings, a SERS chip has been fabricated by the assembly of Au@Ag NPs on a piece of silicon wafer and the further modification with Dpy. The exchange of Dpy from the chip into the aqueous Hg(2+) droplet results in the quenching of Raman signals of Dpy, responding to 10 fM Hg(2+) that is about 6 orders of magnitude lower than the limit defined by the U.S. Environmental Protection Agency in drinkable water. Each test using the SERS chip only needs a droplet of 20 μL sample and is accomplished within ∼4 min. The SERS chip has also been applied to the quantification of Hg(2+) in milk, juice, and lake water.

Highly emissive and air-stable AgInS2-ZnS quantum dots (ZAIS QDs) with quantum yields of up to 20% have been successfully synthesized directly in aqueous media in the presence of polyacrylic acid (PAA) and mercaptoacetic acid (MAA) as stabilizing and reactivity-controlling agents. The as-prepared water-dispersible ZAIS QDs are around 3 nm in size, possess the tetragonal chalcopyrite crystal structure, and exhibit long fluorescence lifetimes (100 ns). In addition, these ZAIS QDs are found to exhibit excellent optical and colloidal stability in physiologically relevant pH values as well as very low cytotoxicity, which render them particularly suitable for biological applications. Their potential use in biological labelling of baculoviral vectors is demonstrated.

We present evidence of topological surface states in β-Ag2Te through first-principles calculations, periodic quantum interference effect and ambipolar electric field effect in single crystalline nanoribbon. Our first-principles calculations show that β-Ag2Te is a topological insulator with a gapless Dirac cone with strong anisotropy. To experimentally probe the topological surface state, we synthesized high quality β-Ag2Te nanoribbons and performed electron transport measurements. The coexistence of pronounced Aharonov-Bohm oscillations and weak Altshuler-Aronov-Spivak oscillations clearly demonstrates coherent electron transport around the perimeter of β-Ag2Te nanoribbon and therefore the existence of topological surface states, which is further supported by the ambipolar electric field effect for devices fabricated by β-Ag2Te nanoribbons. The experimental evidences of topological surface states and the theoretically predicted anisotropic Dirac cone of β-Ag2Te suggest that the material may be a promising candidate of topological insulator for fundamental study and future spintronic devices. Published version

Size-selected silver nanoparticle–polyacrylonitrile (PAN) composites have been synthesized by a simultaneous polymerization–reduction approach, providing highly crystalline silver nanocrystals with a narrow size distribution well dispersed in PAN matrixes.

A novel nanohybrid ratiometric fluorescence probe comprised of carbon dots (C-dots) and hydrophilic CdSe@ZnS quantum dots (QDs) has been developed by simply mixing the blue-emission C-dots with red-emission carboxylmethyldithiocarbamate modified CdSe@ZnS QDs (GDTC-QDs). The nanohybrid ratiometric fluorescence probe exhibits dual emissions at 436 nm and 629 nm under a single excitation wavelength. Due to the strong chelating ability of GDTC on the surface of QDs to mercuric ion (Hg 2+ ), the fluorescence of the GDTC-QDs in the nanohybrid system could be selectively quenched in the presence of Hg 2+ while the fluorescence of the C-dots remained constant, resulting in an obviously distinguishable fluorescence color evolution (from red to blue) of the nanohybrid system. The detection limit of this method was found to be as low as 0.1 μM. Furthermore, the recovery result for Hg 2+ in real samples including tap water and lake water by this method was satisfying, suggesting its potential application for Hg 2+ sensing.

The synergistic effect between metal and TiO(2) nanoparticles brings about new, enhanced functionalities for a myriad of applications, ranging from labeling and sensing to catalysis and surface-enhanced Raman scattering. Although extensive work has been done in the preparation of concentric TiO(2)-coated metal nanostructures, current methods for the synthesis of noncentrosymmetric morphologies are still very limited. This Focus review summarizes the various methods used to prepare TiO(2)-coated metal nanostructures, with a particular emphasis on noncentrosymmetric morphologies, their novel plasmonic properties, and their promising applications in the fields of catalysis and photocatalysis.

Lung is a common site for the occurrence of melanoma metastasis, the mechanism by which primary melanoma affects the lungs before tumor cells arrival is poorly understood. The aim of this study was to explore lung microenvironment response to primary melanoma in the premetastatic phase. Melanoma cells (B16) were implanted into the Balb/c mice back, pulmonary inflammation response was analyzed by wet/dry ratios and H&E staining, the relationship between inflammation cells and metastatic foci was analyzed by bone marrow transplant mouse model, pulmonary vasculature was further analyzed by whole mount staining, and the circulating levels of proinflammatory cytokines in sera were evaluated by mouse cytokine array. In the premetastatic stage, significant inflammation response in lungs was induced by a distant primary melanoma, inflammation cells colonize in premetastatic sites before tumor cells arrived, and the sites of inflammation cells clusters are tumor metastasis sites. VEGF, M-CSF and TNF-α may be the underlying factors responsible for the increased metastasis in the B16-bearing mice. Treatment with celecoxib had effects on inflammation response and reduced cancer metastasis. In the premetastatic phase, the melanoma induces pulmonary inflammation response, changes the lung environment and then facilitates lung metastasis. Thus, inhibition of lung inflammation may provide potential targets for the prevention of metastasis.

The aim of this study was to identify serum protein fingerprints of small cell lung cancer (SCLC) and potential biomarkers related to chemotherapy resistance of SCLC with surface enhanced laser desorption/ionization time of flight mass spectrometry (SELDI-TOF MS). A total of 60 SCLC patients and 48 age- and sex-matched healthy individuals were enrolled. The chemotherapy regimen was cisplatin plus etoposide. All patients received two cycles of chemotherapy. Serum protein profiles were detected using SELDI-TOF MS and the spectra were analyzed with support vector machines (SVMs). Western blotting was performed to verify the results of SELDI-TOF MS. Three top scored peaks, at m/z of 6269, 9043 and 13124 Da, were finally selected as potential biomarkers for detection of SCLC. The SVM classifier separated the SCLC from the healthy samples in the blind test, with a sensitivity of 92.4% and a specificity of 92.5%. For the 56 eligible chemotherapy patients, 4 had a complete response (7.14%), 39 patients had a partial response (69.6%), 9 patients had a stable disease (16.1%) and 4 patients had a progressive disease (7.14%). The model constructed using two protein peaks with m/z of 8830 and 10468 Da separated the chemotherapy-resistant group from the chemotherapy-sensitive group with a sensitivity of 80.0% and a specificity of 80.0%. Initial protein database searching identified 10468 Da as S100-A9 which was confirmed by western blotting. The present results suggest that the combination of SELDI-TOF MS with SVM may provide a useful means in the search for serum biomarkers for predicting chemotherapy resistance in patients with SCLC.

Rod-like nanocrystals of the semiconductor alloy (ZnS)(x)(CuInS(2))(1-x) (ZCIS) have been colloidally prepared by using a one-pot non-injection-based synthetic strategy. The ZCIS nanorods crystallize in the hexagonal wurtzite structure and display preferential growth in the direction of the c axis. The bandgap of these quarternary alloyed nanorods can be conveniently tuned by varying the ratio of ZnS to CuInS(2). A non-linear relationship between the bandgap and the alloy composition is observed. The ZCIS nanorods are found to exhibit promising photocatalytic behaviour in visible-light-driven degradation of Rhodamine B.

Here we report a fast and effective method to visualize interactive proteins across intact mammalian cells via on-site formation of fluorescence using instant reaction of non-fluorescent fluorescamine with primary amines on proteins. Without interference by fluorescence background, this fluorogenic labelling opens a way for selective identification of primary amine-rich interacting proteins, efficient mapping and real-time monitoring of their spatial distribution in assemblies/network, and fast differentiation of cellular types. Without adverse effect on biological functions, this labelling method also provides new insights to comprehend important aspects of cellular functions of organelles and their relation to health imperfections for disease diagnostics and imaging-guided therapy.

Here, we report the shell thickness-dependent Raman enhancement of silver-coated gold nanoparticles (Au@Ag NPs) for the identification and detection of pesticide residues at various fruit peels. The Raman enhancement of Au@Ag NPs to a large family of sulfur-containing pesticides is ~2 orders of magnitude stronger than those of bare Au and Ag NPs, and there is a strong dependence of the Raman enhancement on the Ag shell thickness. It has been shown for the first time that the huge Raman enhancement is contributed by individual Au@Ag NPs rather than aggregated Au@Ag NPs with "hot spots" among the neighboring NPs. Therefore, the Au@Ag NPs with excellent individual-particle enhancement can be exploited as stand-alone-particle Raman amplifiers for the surface identification and detection of pesticide residues at various peels of fruits, such as apple, grape, mango, pear, and peach. By casting the particle sensors onto fruit peels, several types of pesticide residues (e.g., thiocarbamate and organophosphorous compounds) have been reliably/rapidly detected, for example, 1.5 nanograms of thiram per square centimeter at apple peel under the current unoptimized condition. The surface-lifting spectroscopic technique offers great practical potentials for the on-site assessment and identification of pesticide residues in agricultural products.

The first use of non-centrosymmetric Janus Au-TiO(2) photocatalysts in efficient, plasmon-enhanced visible-light hydrogen generation is demonstrated. The intense localization of plasmonic near-fields close to the Au-TiO(2) interface, coupled with optical transitions involving localized electronic states in amorphous TiO(2) brings about enhanced optical absorption and the generation of electron-hole pairs for photocatalysis.

Quantum Dots (QDs) are a new class of semiconductor nanoparticulate luminophores, which are actively researched for novel applications in biology and nanomedicine. In this review, the recent progress in the design and applications of QD labels for in vitro and in vivo imaging of cells is presented. Surface chemical engineering of hydrophobic QDs is required to render them water soluble and biocompatible. Further surface modification and attachment of bioactive molecules to the surface of QDs, such as peptides, aptamers, or antibodies are intensively explored for targeted imaging of living cells, and disease states in animals. Specially designed surface coatings can drastically decrease nonspecific interactions between QDs and cells, minimize degradation of QDs under in vivo physiological conditions, reduce the cytotoxicity of QDs, and prolong circulation lifetimes in animals. New generations of QD probes are also promising for imaging cellular processes at the single-molecule level. Ultimately, QDs as components of complex therapeutic nanosystems are poised to contribute significantly to the field of personalized medicine.

Structural and optical characterization of water soluble, thermo-responsive quantum dot/poly(N-isopropyl acrylamide) (QD/PNIPAM) hybrid particles using fluorescence correlation spectroscopy (FCS) and time-correlated single photon counting (TCSPC) measurements performed at temperatures below and above the lower critical solution temperature (LCST) of PNIPAM is reported. By increasing the temperature above the LCST, the signature of the PNIPAM chain collapse covering the QDs is revealed by FCS measurements. Despite the significant structural change, the TCSPC measurements show that the fluorescence lifetimes remain of the same order of magnitude at T > LCST. Such QD/PNIPAM hybrid particles with water solubility and robust thermo-responsive behavior at physiologically relevant temperatures are potentially useful for (bio)molecular sensing and separation applications.

In this work, we have synthesized eccentric Au@TiO(2) core-shell nanostructures and demonstrated their multiple reuse in the catalytic reduction of 4-nitrophenol.