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Abstract: Platinum nanoparticles (Pt-NPs) were deposited onto N-(trimethoxy-silylpropyl) ethylenediamine triacetic acid (EDTA-silane) modified reduced graphene oxide (EDTA-RGO). The EDTA-RGO/Pt-NPs were coated onto a glass carbon electrode and characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectra, and electrochemical tests. The chelating groups create a micro-environment that is suitable for the catalytic behavior of Pt-NPs. Compared with traditional carbon-based Pt catalysts, EDTA-RGO/Pt-NPs exhibit great tolerance towards poisoning by CO. Graphene-supported Pt nanoparticles can be used for the fabrication of fuel cell electrodes and other catalytic devices. [Copyright &y& Elsevier]

Abstract: A novel electrochemical sensor for chlorophenols was fabricated by using the Pd-graphene nanocomposite and ions liquid. The Pd-graphene nanocomposite was prepared via a sonoelectrochemical route, and the possible formation mechanism was proposed. Transmission electron microscopy, scanning electron microscopy, X-ray diffraction and Raman spectrum were used for the characterization of structure and morphology of the nanocomposite. The experimental results showed that Pd nanospheres comprised of small Pd nanoparticles were uniformly attached on graphene sheets. The electrocatalytic properties were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV), which indicated that the Pd-graphene nanocomposite had high activity for chlorophenol oxidation. Herein, 2-chlorophenol was selected as the model molecules. The results showed that graphene played an important role in the fabrication of the chlorophenols sensor. The nanocomposite with large electrochemical active surface led to the excellent electrocatalytic activity, and ionic liquid further enhanced the catalytic activity of Pd-graphene for chlorophenols. [Copyright &y& Elsevier]

Abstract: The sorption of Cu as affected by pH, ionic strength, competitor heavy metal, and inorganic and organic ligands on a Fe-deformed montmorillonite complex was observed in the current study. The results showed that the sorption of Cu was pH dependent and insensitive to a change of ionic strength, indicating that the formation of an inner-sphere complex was the primary sorption mechanism, and it was probably due to the high surface coverage of Fe (oxyhydr)oxides as nanoparticles on deformed montmorillonite. Copper was less effective than Pb in competitive sorption. Phosphate, sulfate and oxalate showed different characteristics in affecting Cu sorption. Phosphate inhibited Cu sorption at a relatively low ligand concentration while a facilitating effect was observed when the concentration of phosphate was relatively high. The sorption of Cu was generally promoted by sulfate but the extent was less than that by phosphate. Oxalate promoted Cu sorption at a relatively low pH (pH 3.5) and a relatively low oxalate concentration, while a significant diminution of Cu sorption was found at higher pHs (pH 4.5 and 5.5) or a relatively high ligand concentration. The results obtained in the current study are of significant importance for evaluating the mobility of Cu in polluted environment. [Copyright &y& Elsevier]

Abstract: The gold nanoparticles/colloidal carbon sphere hybrid material was used for the immobilization of protein, and was developed in biosensing. The hybrid material was fabricated by the assembly of gold nanoparticles onto the surface of colloidal carbon spheres, which constructed a 3D antibody immobilization matrix on the glass carbon electrode and made the immobilized biomolecules hold high stability and bioactivity. After the sandwich-type immunoreaction, the formed HRP-labeled immunoconjugate showed good enzymatic activity for the oxidation of o-phenylenediamine by H2O2. The approach provided a linear response range between 5 and 250ng/mL with a detection limit of 1.8ng/mL. The immunosensor showed good precision, acceptable stability and reproducibility and could be used for the detection of human IgG in real samples, which provided a potential alternative tool for the detection of protein in clinical laboratory. [ABSTRACT FROM AUTHOR]

Abstract: Porous spheres of CuSCN nanoparticles with an average diameter of 0.4–0.6 μm have been prepared by a simple reaction between CuO suspension, NH2OH and KSCN in the presence of gelatin at 10 °C. Gelatin played a decisive role as an inhibitor of the direct attack of NH2OH, KSCN to CuO surfaces and coagulation of the growing CuSCN in producing porous spheres. The products were characterized by X-ray powder diffraction, transmission electron microscopy, and X-ray photoelectron spectra techniques. [Copyright &y& Elsevier]

Cubes of CuBr with an average dimensions of 0.3–0.8 μm have been prepared by a simple reaction between CuO suspension, NH2OH and KBr in the presence of deionized gelatin at 40°C. Gelatin played a decisive role as an inhibitor of the direct attack of NH2OH, KBr to CuO surfaces and coagulation of the growing CuBr in producing the cubes. The products were characterized by X-ray powder diffraction, transmission electron microscopy, X-ray photoelectron spectra techniques and UV-visible absorption spectroscopy. The sizes of the subunits of the polycrystalline CuBr particles were estimated by Debye–Scherrer formula according to XRD spectrum. [Copyright &y& Elsevier]

Au and Ag Noble metals nanowire arrays have been successfully prepared by a photochemical method in porous anodic aluminum oxide template from an aqueous solution of HAuCl4 and AgNO3 in the presence of polymer capping materials PVA at room temperature. The products were characterized by XRD, TEM and SEM. These nanowires have uniform diameters of about 20 nm, which correspond to the pore sizes of the templates used, and lengths are up to tens of micrometers. This approach can be used to fabricate crystalline nanowire arrays of a wide range of other metals and semiconductor materials. [Copyright &y& Elsevier]

A convenient sonochemical process for the preparation of HgSe nanoparticles by using different reductants has been discovered. The HgSe nanoparticles, which were prepared in polyethylene glycol 400 (PEG 400), dextrose and hydroxylamine reductive systems, were analyzed by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). It was found that all the products were cubic phase HgSe by XRD measurements. The TEM observations showed that the HgSe nanoparticles were monodispersed and electron diffraction images of selected areas show that the products were polycrystalline. The sizes of most of all the HgSe nanoparticles were mainly among 30–40 nm, which were in coincidence with the very sizes that were estimated by Debye–Scherrer equation from the XRD patterns. XPS result showed that the ratio of Hg to Se was 57:43, indicating that the final products were rich in mercury. [Copyright &y& Elsevier]

Hollow spheres of Cu2O with an average diameter of 0.3–0.6 μm have been prepared by a simple reaction between CuO suspension and NH2OH in the presence of deionized gelatin at room temperature. Gelatin played a decisive role as an inhibitor of the direct attack of NH2OH to CuO surfaces and coagulation of the growing Cu2O in producing the hollow spheres. The products were characterized by X-ray powder diffraction, transmission electron microscopy, X-ray photoelectron spectra techniques and UV-visible absorption spectroscopy. The band gap is estimated to be 2.60 eV according to the results of optical measurements of the hollow spheres. [Copyright &y& Elsevier]

Rectangular lead selenide and cadmium selenide nanoparticles have been successfully prepared by a photochemical method from an aqueous solution of lead acetate, cadmium chlorate, and sodium selenosulfate in the presence of complexating agents of nitrilotriacetic acid at room temperature. It was found that the effects of the photonic intensity, the pH of the solution, and the species of complexating agents played important roles on the morphology control of the PbSe and CdSe nanoparticles. The products were characterized by X-ray diffraction, electron microscopy, X-ray photoelectron spectra, and photoluminescence spectrum. The mechanism for the formation of the PbSe and CdSe was discussed. [Copyright &y& Elsevier]

Nanocrystalline SnO2 powders of about 3 nm in size have been prepared by a microwave irradiation heating technique from an aqueous solution in the presence of SnCl4 and urea. The nanocrystalline SnO2 particles were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), differential scanning calorimetric (DSC), thermogravimetric analysis (TG), and reflection spectrum. A bandgap is estimated to be 4.5 eV from the optical measurement of the nanoparticles. [Copyright &y& Elsevier]

In this study, we proposed 'switching ultrasonic amplitude' as a new strategy of applying ultrasonic energy to prepare a hybrid of buckminsterfullerene (C 60) and gallium oxide (Ga 2 O 3), C 60 /Ga 2 O 3. In the proposed method, we switched the ultrasonic amplitude from 25% to 50% (by 5% amplitude per 10 min, within 1 h of ultrasonic irradiation) for the sonochemical treatment of a heterogeneous aqueous mixture of C 60 and Ga 2 O 3 by a probe-type ultrasonic horn operating at 20 kHz. We found that compared to the conventional techniques associated with high amplitude oriented ultrasonic preparation of functional materials, switching ultrasonic amplitude can better perform in preparing C 60 /Ga 2 O 3 with respect to avoiding titanium (Ti) as an impurity generating from the tip erosion of a probe-type ultrasonic horn during high amplitude ultrasonic irradiation in an aqueous medium. Based on SEM/EDX analysis, the quantity of Ti (wt.%) in C 60 /Ga 2 O 3 prepared by the proposed technique of switching ultrasonic amplitude was found to be 1.7% less than that prepared at 50% amplitude of ultrasonic irradiation. The particles of C 60 /Ga 2 O 3 prepared by different modes of amplitude formed large (2–12 μm) aggregates in their solid phase.Whereas, in the aqueous medium, they were found to disperse in their nano sizes. The minimum particle size of the as-synthesized C 60 /Ga 2 O 3 in an aqueous medium prepared by the proposed method of switching ultrasonic amplitude reached to approximately 467 nm. Comparatively, the minimum particle sizes were approximately 658 nm and 144 nm, using 25% and 50% amplitude, respectively. Additionally, Ga 2 O 3 went under hydration during ultrasonic irradiation. Moreover, due to the electron cloud interference from C 60 in the hybrid structure of C 60 /Ga 2 O 3 , the vibrational modes of Ga 2 O 3 were Raman inactive in C 60 /Ga 2 O 3. [ABSTRACT FROM AUTHOR]

• Silver nanorods/nanowires were prepared within the range of sub-20 nm diameter. • The diameter can be controlled, as small as 12 nm, using 5-nm spherical Au seeds. • One-dimensional trimetallic (Au@Pd-Ag) hollow products were prepared via GRR. We report a facile synthesis of silver nanorods/nanowires with the diameter in the range of sub-20 nm via seeded growth. The key to the success of this work relies on the use of tiny Au seeds and manipulation over reaction kinetics. In particular, their diameter could be controlled to as small as 12 nm using 5-nm spherical Au seeds. They can be further converted to trimetallic (Au@Ag-Pd) hollow derivatives with tunable hollow degree and elemental compositions by galvanic replacement reaction. [ABSTRACT FROM AUTHOR]

Abstract: Herein, we reported the quenching effect of Ni2+ on bovine serum albumin protected fluorescent gold nanoparticles (BSA-GNPs). The quenching mechanism was discussed and a static quenching mechanism was proposed. The number of binding sites (n), apparent stability constants (K) and corresponding thermodynamic parameters of BSA-GNPs-Ni2+ complex were measured at different temperatures. Under optimum conditions, the fluorescence intensity of BSA-GNPs is linearly proportional to nickel concentration from 6.0×10−8 mol/L to 8.0×10−6 mol/L with a detection limit of 1.0×10−8 mol/L. The result indicated that BSA-GNP was a potential Ni2+ probe. [Copyright &y& Elsevier]

Abstract: TiO2 nanoparticles were homogeneously coated on multiwalled carbon nanotubes (MWCNTs) by hydrothermal deposition, and this nanocomposite might be a promising material for myoglobin (Mb) immobilization in view of its high biocompatibility and large surface. The glassy carbon (GC) electrode modified with Mb–TiO2/MWCNTs films exhibited a pair of well-defined, stable and nearly reversible cycle voltammetric peaks. The formal potential of Mb in TiO2/MWCNTs film was linearly varied in the range of pH 3–10 with a slope of 48.65 mV/pH, indicating that the electron transfer was accompanied by single proton transportation. The electron transfer between Mb and electrode surface, k s of 3.08 s−1, was greatly facilitated in the TiO2/MWCNTs film. The electrocatalytic reductions of hydrogen peroxide were also studied, and the apparent Michaelis–Menten constant is calculated to be 83.10 μM, which shows a large catalytic activity of Mb in the TiO2/MWCNTs film to H2O2. The modified GC electrode shows good analytical performance for amperometric determination of hydrogen peroxide. The resultant Mb–TiO2/MWCNTs modified glassy carbon electrode exhibited fast amperometric response to hydrogen peroxide reduction, long term life and excellent stability. Finally the activity of the sensor for nitric oxide reduction was also investigated. [Copyright &y& Elsevier]

Abstract: The photoluminescence from water-soluble gold nanoparticles, each composed of a 5.1nm gold core and a bovine serum albumin (BSA)-protected layer, has been observed. The maximal excitation and the maximal emission wavelength are at 320 and 404nm, respectively. The photoluminescence quantum yield is estimated as 0.053±0.0070, at room temperature. The mechanism of the luminescence is hypothesized to be associated with interband transitions between the filled 5d10 band and 6(sp)1 conduction band. The photoluminescence is sensitive to pH, organic solvents and metal ions. These observations suggest that this nanoparticles are a viable alternative to organic fluorophores or semiconductor nanoparticles for biological labeling and imaging. [Copyright &y& Elsevier]

Abstract: Antimony dendrites have been successfully synthesized by a microwave-assisted method under ambient air from the solution containing antimony sodium tartrate. In the reaction, zinc powders were selected as a reductant for the fabrication. The as-prepared products were characterised by X-ray powder diffraction, transmission electron microscopy, and selected area electron diffraction. The dendrites were found to be composed of well-crystallized nanoflakes with size of 20–40 nm. [Copyright &y& Elsevier]

CuO nanoparticles with an average size of ca. 4 nm have been successfully prepared by microwave irradiation, using copper (II) acetate and sodium hydroxide as the starting materials and ethanol as the solvent. The CuO nanoparticles are characterized by using techniques such as X-ray powder diffraction, transmission electron microscopy, selected area electron diffraction, X-ray photoelectron spectroscopy and UV–Visible absorption spectroscopy. The as-prepared CuO nanoparticles have regular shape, narrow size distribution and high purity. The band gap is estimated to be 2.43 eV according to the results of the optical measurements of the CuO nanoparticles. [Copyright &y& Elsevier]

• This study explores the free vibration and bending of FG-GPLRC spherical shells based on the three-dimensional elasticity theory. • The analytical solutions are obtained. • Further illustrative parametric investigations are performed with respect to the distribution pattern, the weight fraction, and the geometric parameters of GPLs. • For free vibration, the FG-A, FG-O and FG-X increase the natural frequencies of breathing, torsional and fundamental modes more effectively, respectively; While for bending, FG-X possesses the smallest displacement, and FG-V holds the lowest stress. This paper presents analytical investigations on the free vibration and static bending of functionally graded graphene-reinforced nanocomposite (FG-GPLRC) spherical shells. The GPL nanofillers are dispersed into polymer matrix uniformly and un-uniformly in the thickness direction with a piece-wise type, and UD, FG-O, FG-X, FG-V and FG-A types of GPL distribution patterns are taken into account. The effective material properties of graphene-reinforced nanocomposites are estimated by using the modified Halpin-Tsai multi-scaled model and the rule of mixtures. Governing differential equations for free vibration and bending of the FG-GPLRC spherical shells are derived based on the three-dimensional elasticity theory with the aid of the state space method, and the layer-wise model is employed to obtain the analytical solutions. The validity of the present method is first examined, followed by the illustrative parametric studies to further scrutinize the free vibration and static bending behaviors of the FG-GPLRC spherical shells with the various reinforcement schemes, including the distribution pattern, the weight fraction, and geometric parameter of GPLs in details. [ABSTRACT FROM AUTHOR]

Abstract The behavior of clay minerals in different size fractions of soil colloids are very particular, mostly in the nanoparticle (25–100 nm) fractions, where clay minerals are very reactive and have a significant role in the transport of nutrients. In this work, the characterizations of clay minerals in the particle fractions (<2000, 450–2000, 100–450, and 25–100 nm) of an Oxisol and an Alfisol were studied by conventional and synchrotron X-ray diffraction (XRD), fourier-transform infrared spectroscopy (FTIR), inductively coupled plasma-optical emission spectroscopy (ICP-OES), and thermogravimetric analysis (TG) to better understand the transformations of clay minerals and their crystalline structure within the size particle fractions. Kaolinite dominated in all the particle size fractions and the moderate amount of HIV and illite present in the larger size particles (<2000, 450–2000 and 100–450 nm) reduced gradually in nanoparticles of the Oxisol. Kaolinite dominated in the bulk samples (<2000 nm), vermiculite prevailed in the 450–2000 nm fraction; illite, kaolinite and vermiculite were equally common in the 100–450 nm fractions, and illite dominated in the nanoparticles of the Alfisol. The reduction of kaolinite and the transformation of illite into vermiculite in the Alfisol occurred along the particle size fractions. The increase of the FWHM values, the deformation of the hydroxyl group of kaolinite and illite as well as the highest total of weight loss in their crystals occurred in the nanoparticles of the Alfisol rather than the Oxisol. It revealed that the reduction in crystal ordering in the crystals of clay minerals was greater in the nanoparticle fraction of the Alfisol compared to the Oxisol. The influence of climate, vegetation, parent material has been evidenced in the transformation of clay minerals in this study. Highlights • Illite dominated in the nanoparticles of Alfisol while kaolinite was in the Oxisol. • Illite and HIV have contributed to form kaolinite from nanoparticles in the Oxisol. • In the Alfisol, kaolinite strongly reduced with decreasing particle size fractions. • The disorder was significant in the clay mineral's crystalline structure of Alfisol. • Climate, vegetation, parent material have contributed to transform clay minerals [ABSTRACT FROM AUTHOR]

The accurate therapeutic evaluation for chronic myeloid leukemia (CML) drug is of great importance to minimize side effects and enhance efficacy. Herein, a facile and precise surface-enhanced scattering (SERS) approach based on coupled plasmonic field has been introduced to evaluate the therapeutic outcomes of antileukemia drug through ultrasensitive assay of caspase-3 activity in apoptotic cells. Caspase-3 as an apoptosis indicator could specifically cleave the N-terminus of biotinylated DEVD-peptide (biotin-Gly-Asp-Gly-Asp-Glu-Val-Asp-Gly-Cys) immobilized on the Au nanoparticle-decorated TiO 2 nanotube arrays (TiO 2 /Au NTAs) substrate. After the enzyme cleavage with caspase-3, Raman-labelled Au nanostar (AuNS) probes captured the residual DEVD-peptides via the recognition between streptavidin and biotin, thus resulting in an enhanced Raman response on the SERS platform. The variation of Raman intensity revealed caspase-3 activity that reflected the chemotherapeutic effect. On this platform, AuNS nanoprobes offered a large number of binding sites and intrinsic “hot spots” for Raman reporters, while TiO 2 /Au NTAs rendered a homogenously coupled electromagnetic field between the adjacent repeated units over the large area. In particular, a spatially expanding plasmonic field formed by coupling AuNSs with TiO 2 /Au NTAs would further heighten Raman enhancement. Taking these advantages, the strong and uniform Raman signals were achieved. Furthermore, the practicability investigation witnessed that the proposed SERS strategy was available to evaluate the therapeutic effect of dasatinib on CML K562 cells. The developed method possesses fascinating advantages of cost-effectiveness, excellent reproducibility and high sensitivity, which endows it with promising potential in apoptosis monitoring and anticancer drug development. [ABSTRACT FROM AUTHOR]

Three dimensional carbon materials with hirerarchically porous structure could exhibit superior energy storage performance than two dimensional stacked carbon nanosheet materials. In this work, we prepared a novel ZIF-8-derived nitrogen doped carbon nanoparticles/graphitic carbon nitride composite electrode material with high electrochemical energy storage performances, including high specific capacitances (495 F g −1 at 0.1 A g −1 and 188 F g −1 at 20 A g −1 ) and a stable cycling durability with no capacitance declination after 5000 charge-discharge cycles in three-electrode system. When assembled as electrode materials in symmetrical two-electrode system, the as-prepared composite electrode material could exhibit high specific capacitances of 349.7 F g −1 at 0.5 A g −1 and 261.2 F g −1 at 5 A g −1 . Accordingly, a high energy density of 11.89 Wh/kg can be achieved at the power density of 247.40 W kg −1 . The improvement stems from its hierarchically porous structure with dominant pore sizes at 3 nm and among 4–40 nm, as well as high exposed pyridinic nitrogen (8.58 at%) and pyrrolic nitrogen (3.59 at%) active sites caused by the insertion of ZIF-8-derived nitrogen doped carbon nanoparticles between g-CN layers. This study has provided a new idea on the design of graphitic carbon nitride nanostructures with improved doping level and hiearchically porous structure. [ABSTRACT FROM AUTHOR]

CO oxidation has been performed on Co 3 O 4 nanocubes and Co(OH) 2 nanosheets as model catalysts. The reaction rate of CO on Co 3 O 4 /Co(OH) 2 nanocomposites obtained by one-pot synthesis is about ~ two orders of magnitude higher than that on Co 3 O 4 nanomaterials. The catalytic behaviors of different nanomaterials revealed that the assembly with nano building blocks cause the catalytic sites much more active for CO oxidation. The kinetic data showed that the activation energy for CO oxidation over Co 3 O 4 /Co(OH) 2 nanocomposites was lower than that of other nanomaterials. Since Co(OH) 2 nanosheets can prevent Co 3 O 4 nanocubes aggregating, nanocomposites kept good catalytic stability. [ABSTRACT FROM AUTHOR]

The composition, structure and transformation characteristics of clay minerals in various size particles (< 2000, 450–2000, 100–450 and 25–100 nm) of two Alfisols (Haplustalf and Hapludalf) in China were investigated by elemental analysis, X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FT-IR) and 27 Al and 29 Si Magic-angle Spinning Nuclear Magnetic Resonance (MAS NMR). The clay minerals in < 2000, 450–2000 and 100–450 nm size particles of the two soils were illite, vermiculite, smectite, kaolinite and kaolinite interstratified minerals. In Haplustalf, vermiculite was dominant clay mineral in 450–2000 nm particles and illite was dominant clay mineral in 100–450 nm particles. In Hapludalf, kaolinite (and kaolinite interstratified minerals) predominated in all size particles. With decreasing particle sizes, the two clays showed a decrease in K 2 O, Na 2 O, MgO and SiO 2 contents and an increase in Al 2 O 3 content, with the minimum molar ratio of SiO 2 to Al 2 O 3 observed in nanoparticles (25–100 nm). Meanwhile, the smectite and vermiculite contents decreased or disappeared, leaving illite and kaolinite (and kaolinite interstratified minerals) as the main clay minerals in the two soil nanoparticles. Additionally, with decreasing particle sizes, the clay mineral structures were transformed from well crystalline to poor crystalline, with illite being the poor crystalline in nanoparticles of the soils. The hydroxyl groups between the tetrahedral and octahedral structures of the 2:1 clay minerals and the surface of kaolinite gradually broke down, and IV Al of the tetrahedral structure gradually reduced. In nanoparticles, Al mainly appeared in the octahedral structure as VI Al, and Si in the structure of Q 3 (Si linked to three other Si atoms via oxygen). The composition and structure of clay minerals in different size particles showed that the clay minerals weathered from larger particles (> 100 nm) were an important mineral source of nanoparticles, and the 1:1 clay minerals were mainly inherited from the minerals in larger particles and transformed from 2:1 clay minerals into nanoparticles. [ABSTRACT FROM AUTHOR]

Abstract: Covalent organic frameworks (COFs) are a new generation of porous materials constructed from light elements linked by strong covalent bonds. Herein we present rapid preparation of highly fluorescent nanoparticles of a new type of COF, i.e. melamine-based porous polymeric network SNW-1, by a microwave-assisted synthesis route. Although the synthesis of SNW-1 has to be carried out at 180°C for 3d under conventional reflux conditions, SNW-1 nanoparticles could be obtained in 6h by using such a microwave-assisted method. The results obtained have clearly demonstrated that microwave-assisted synthesis is a simple yet highly efficient approach to nanoscale COFs or other porous polymeric materials. Remarkably, the as-synthesized SNW-1 nanoparticles exhibit extremely high sensitivity and selectivity, as well as fast response to nitroaromatic explosives such as 2,4,6-trinitrotoluene (TNT), 2,4,6-trinitrophenylmethylnitramine (Tetryl) and picric acid (PA) without interference by common organic solvents, which is due to the nanoscaled size and unique hierarchical porosity of such fluorescence-based sensing material. [Copyright &y& Elsevier]

Abstract: PbS and Bi2S3 nanocrystals with well-controlled sizes and shapes were easily produced from molecular precursors (xanthate) in ethylene diamine (en) solution at room temperature. When lead or bismuth ethylxanthate were added into en solution, the precipitates were instantly formed, and subsequently, PbS cubes and flower-like Bi2S3 hierarchical structures were obtained if the mixtures were left still for 5days under ambient conditions. This work not only provides a facile route to synthesize chalcogenides with well-defined nano- and microstructures in a solution-phase system, but also gives insight into understanding on decomposition behavior of molecular precursors in various solvents. [Copyright &y& Elsevier]

Abstract: A sensitive colorimetric detection for biomolecules based on aptamer was described. Poly(dimethylsiloxane) (PDMS)–gold nanoparticles (AuNPs) composite film was used as a platform for immobilizing anti-target aptamer. PDMS–AuNPs composite film only covered with aptamer showed high inhibiting ability towards silver reduction, after target molecules were conjugated on the modified surface, the catalytic efficiency of AuNPs for silver reduction was increased. In this system, the darkness density of silver enhancement was applied for target quantitative measurement. Lysozyme and adenosine 5′-triphosphate (ATP) were tested as the models, quantitative measurements with imaging software or semiquantitative measurements with naked eyes were carried out in the range of 1×10−2–1μg/mL and 1×10−4–1×103 μg/mL, the volume of reagent using in each assay is 15μL or less. We speculated that aptamer-target conjugates’ inhibition ability for AuNPs’ catalytic efficiency toward silver reduction might come from charge and spatial effects. This study can offer a completely novel and relatively general approach for colorimetrical aptamer sensors with good analytical properties and potential applications. The sensor could be coupled with digital transmission of images for remote monitoring system in diagnosis, food control, and environmental analysis. [Copyright &y& Elsevier]

Abstract: In this paper, stabilizer-free gold nanoparticles (Au NPs) were synthesized by a facile pulse sonoelectrochemical method in the absence of stabilizer. The size and shape of the Au NPs can be controlled by adjusting current density, reaction time and the pH value of the precursor solution. The morphology and structure of the Au NPs were characterized by transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), UV–visable spectra (UV–vis), energy-dispersive X-ray (EDX) and X-ray diffraction (XRD). The pH value has a great effect on the size and dispersion of the obtained Au NPs. The Au NPs could further used as substrate for fabrication of HRP biosensor which exhibited excellent biocatalytical activity with high sensitivity and rapid response. This method provides a facile route for the synthesis of stabilizer-free Au NPs. Since the preparation process do not need the addition of any surfactants/capping agent, the resulting Au NPs are suitable for the applications in fields of biology and catalysis. [Copyright &y& Elsevier]

Abstract: An electroosmotic flow (EOF)-switchable poly(dimethylsiloxane) (PDMS) microfluidic channel modified with cysteine has been developed. The native PDMS channel was coated with poly(diallyldimethylammonium chloride) (PDDA), and then gold nanoparticles by layer-by-layer technique was assembled on PDDA to immobilize cysteine. The assembly was followed by infrared spectroscopy/attenuated total reflection method, contact angle, EOF measurements and electrophoretic separation methods. EOF of this channel can be reversibly switched by varying the pH of running buffer. At low pH, the surface of channels is positively charged, EOF is from cathode to anode. At high pH, the surface is negatively charged, EOF is from anode to cathode. At pH 5.0, near the isoelectric point of the chemisorbed cysteine, the surfaces of channels show neutral. When pH is above 6.0 or below 4.0, the magnitude of EOF varies in a narrow range. And the modified channel surface displayed high reproducibility and good stability, a good reversibility of cathodic–anodic EOF transition under the different pH conditions was observed. Separation of dopamine and epinephrine as well as arginine and histidine were performed on the modified chip. [Copyright &y& Elsevier]

Abstract: A novel method was proposed to prepare a series of functionalized Ag2S nanoparticles capped with various aminopolycarboxylic acids. The as-prepared Ag2S nanoparticles were characterized by UV–vis, FTIR, resonance light scattering spectra (RLS) and transmission electron microscopy (TEM). Based on the RLS intensities enhanced by BSA-induced Ag2S nanoparticles aggregation, a sensitive RLS method for the detection BSA at nanogram levels was established. The detection limits for BSA are between 8.6 and 112.6ngmL−1, depending on the different capping agents. The effects of various capping agents on the detection limits of BSA have been investigated. The detection limit is found to be dependent on the stability constant (log K MY) of the silver–aminopolycarboxyl complexes. [Copyright &y& Elsevier]

Abstract: The nanocomposite composed of carboxymethyl chitosan (CMCS) and gold nanoparticles was successfully prepared by a novel and in situ process. It was characterized by transmission electron microscopy (TEM) and Fourier transform infrared spectrophotometer (FTIR). The nanocomposite was hydrophilic even in neutral solutions, stable and inherited the properties of the AuNPs and CMCS, which make it biocompatible for enzymes immobilization. HRP, as a model enzyme, was immobilized on the silica sol–gel matrix containing the nanocomposite to construct a novel H2O2 biosensor. The direct electron transfer of HRP was achieved and investigated. The biosensor exhibited a fast amperometric response (5s), a good linear response over a wide range of concentrations from 5.0×10−6 to 1.4×10−3 M, and a low detection limit of 4.01×10−7 M. The apparent Michaelis–Menten constant () for the biosensor was 5.7×10−4 M. Good stability and sensitivity were assessed for the biosensor. [Copyright &y& Elsevier]

Abstract: A hydrophilic poly(dimethylsiloxane) (PDMS) microchip with stable electroosmotic flow (EOF) was prepared by a simple and reproducible coating procedure with silica nanoparticles. The microchannel wall of PDMS chip was coated with a layer of poly(diallyldimethylammonium chloride) (PDDA) and then collected silica nanoparticles. The assembly was followed by contact angle, charge-coupled device (CCD) imaging, electroosmotic flow (EOF) measurements and electrophoretic separation experiments. Contact angle measurements revealed the coated surface was hydrophilic; the water contact angle for coated chips was 64° compared with a water contact angle for native PDMS chips of 113°. CCD images indicated a substantially more hydrophilic microchannel than native PDMS. We carried out a comparison and concluded that the EOF values on the coated PDMS chip were close to those values on the glass chip above pH 7.0. The coated channel had an excellent stability and reproducibility, RSD of EOF values (n =6) on native and coated PDMS microchip was 1.58 and 0.57%, respectively. Separation of dopamine and epinephrine was performed on the coated chip generated 1.40×105, 1.39×105 theoretical plates/m compared with the native PDMS chip of 0.79×105, 0.88×105, high resolution of 1.7 was achieved with a channel of 3.60cm length. [Copyright &y& Elsevier]

Abstract: 2-Hydroxypropyl-β-cyclodextrin was used as a template to fabricate hollow spherical copper sulfide nanoparticle assemblies in the presence of sonication. The as-prepared spheres were uniform in shape and have well-defined shells composed of one-layered CuS nanoparticles. The interaction between the Cu ions and HP-β-CD was confirmed by the FTIR. The effects of the sonication were studied and a possible self-assembly mechanism was discussed. [Copyright &y& Elsevier]

Abstract: Dimethylglycoxime (DMG) functionalized copper nanoparticles (DMG-CuNPs) were prepared by a microwave heating method and characterized by TEM, FTIR, and XRD. The as-prepared nanoparticles were used to construct a new glucose sensor. Experimental results showed that DMG could be used to encapsulate the copper nanoparticles to control their growth during the preparation process and could chelate copper ions which were produced during the positive scan in the electrochemical experiments. The sensor showed good selectivity and sensitivity. A wide linearity range and a low detection limit have been assessed for it. A linear response to glucose in the concentration range between 1.0×10−6 and 5.0×10−3 M and a detection limit of 5.0×10−7 M were observed. Most important of all, the common drawback of copper electrode fouling was overcome in this sensor. [Copyright &y& Elsevier]

Abstract: We report the first observation of electrogenerated chemiluminescence (ECL) from CdS spherical assemblies in both nonaqueous system and aqueous system. The CdS spherical assemblies consist of CdS nanocrystals about 5 nm in diameter. Four ECL peaks were found under cyclic voltammetric conditions. According to the annihilation mechanism and two-equivalent adsorbed surface state theory, the mechanism for ECL peaks was proposed. The morphology of the CdS spherical assemblies is proved to play an important role in maintaining the stability of partial electrogenerated species to generate the ECL light. [Copyright &y& Elsevier]

Abstract: The nanosized silver particles are used to dope into the sol–gel film to prepare a biosensor. The horseradish peroxidase (HRP), mediator methylene blue (MB), nanosized silver particles and sol–gel solution are mixed and coated on the surface of glass carbon (GC) electrode to get the biosensor. The silver nanoparticles in the sol–gel film can adsorb the enzyme molecules and improve the sol–gel film conductivity. The biosensor has a high sensitivity, quickly response to H2O2 and good stability. The biosensor responds to H2O2 in the linear range from 1 μM to 1 mM. The detection limit was down to 0.4 μM when the signal to noise ratio is 3. The apparent Michaelis-Menten constant of the biosensor to H2O2 was estimated to be 1.2 mM, showing a high affinity. [Copyright &y& Elsevier]

Monodisperse silver nanoparticles stabilized with PVP have been prepared in a saturated solution of silver citrate (Ag3C6H5O7) in the presence of poly(vinyl pyrrolidone) (PVP) by a pulsed sonoelectrochemical technique. [Copyright &y& Elsevier]

A novel sonochemical method for preparation of mercury selenide has been developed based on the reaction of mercury acetate and sodium selenosulfate in an aqueous system at room temperature. Different complexing agents were used to control the particle size. X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) were used to determine the phase, purity, size and morphology of the products. The results showed that the HgSe nanoparticles with different sizes could be obtained in the presence of complexing agents. [Copyright &y& Elsevier]

A dual-potential ratiometric electrochemiluminescence biosensor based on Au@CDs nanoflowers, Au@luminol nanoparticles and an enzyme-free DNA nanomachine for ultrasensitive p53 DNA detection. • A dual-potential ratiometric ECL biosensor was fabricated based on Au@CDs and Au@luminol. • An enzyme-free DNA walker was employed. • Sensitive and accurate detection of p53 DNA were obtained. Herein, an amplified electrochemiluminescence (ECL) ratiometric biosensor for p53 DNA sequence assay was described based on gold@carbon dots nanoflowers (Au@CDs), gold@luminol nanoparticles (Au@luminol) as luminophors and an enzyme-free DNA walker for signal amplification. The ratiometric strategy endowed the sensor with a prominent accuracy. Taking advantage of DNA-walker signal amplification feature, a high sensitivity for target detection was achieved. Under the optimal conditions, the designed biosensor exhibited a lower limit of 0.34 fM and wide linear range from 1 fM to 10 pM for p53 DNA sequence detection. In particular, compared with traditional Ru(bpy) 3 3+/Ru(bpy) 3 2+ derivatives and semiconductor nanoparticles, Au@luminol and Au@CDs have the advantages of cost-effective, excellent biocompatibility, and easy labeling, which offered new opportunity for building ratiometric ECL biosensor platform. [ABSTRACT FROM AUTHOR]

Abstract: A photochemical reaction route was developed to synthesize bismuth selenide (Bi2Se3) nanoparticles and nanorods. In an aqueous solution, bismuth nitrate (Bi(NO3)3) reacted with sodium selenosufate in the presence of reducing agent and complexing agent, and the dispersed Bi2Se3 nanoparticles were obtained with the average size of 35 nm. The nanorods were prepared via an alumina template route in the same solution. We carried out experiments to study the formation mechanism in the morphology control of the products and found that series of factors played an effective role including the irradiation time, pH value, the reducing agents and the species of complexing agents. The products were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). [Copyright &y& Elsevier]

Porous spherical CuI nanoparticles with an average diameter of 0.3–0.6 μm have been prepared by a simple reaction between CuO suspension, NH2OH · HCl and KI in the presence of deionized gelatin at room temperature. [Copyright &y& Elsevier]