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The high toxicity and mobility of hexavalent chromium (Cr(VI)) allow it to easily spread and bioaccumulate, and its detection is a major part of environmental protection. In this work, an innovative method is developed for preparation of cerium oxide nanorod-templated metal-organic frameworks (CeO 2 NRs-MOF). The in situ growth of MOF on the surface of CeO 2 nanorods (CeO 2 NRs) enhances its oxidase-like activity. In the presence of a trace amount of Cr(VI), CeO 2 NRs-MOF can significantly accelerate the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) due to Cr(VI)-boosted oxidation, resulting in a blue colored oxidation product. It can detect Cr(VI) over a range of 0.03-5 μM with high selectivity. Moreover, this method can be applied to the detection of Cr(VI) in different water environment samples with satisfactory recoveries, demonstrating the potential application of CeO 2 NRs-MOF for the direct monitoring of Cr(VI) in environmental water systems. Thus, this work provides a facile host-templated MOF preparation method, which could possibly be extended to other fields.

A fluorometric method is described for the determination of thrombin. Polymer nanoparticles containing the luminol-terbium(III) complex (luminol-Tb) were prepared where luminol acts as the bridging ligand, and Tb(III) acts as the central metal ion. Thrombin possesses a large number of electrons donating groups that coordinate with luminol-Tb. Following coordination, the rigidity of the linker is increased, and this decreases the non-radiative decay rate and induces an increase in fluorescence intensity at 430 nm. Hence, thrombin can be fluorometrically determined. The detection limit of thrombin is as low as 3.5 pM (at an SNR of 3). This is about 10 times lower than assays using an aptamer. The method was applied in the determination of thrombin in human serum via the standard addition method and gave satisfying results. Graphical abstractSchematic representation of the preparation of the luminol-Tb(III) complex in a nanoparticle host by the self-assembly of luminol and Tb(III) ions. Thrombin readily coordinates with the luminol-Tb(III) system, and this results in particle aggregation. The blue fluorescence of luminol increases strongly, and this effect provides the basis for fluorometric determination of thrombin.

The widespread use of zinc oxide nanoparticles (ZnO NPs) has resulted in their release to the environment. There has been concern about the ecotoxicity of ZnO NPs, but little is known about their toxic mechanisms. In the present study, we conducted acute toxicity tests to show that ZnO NPs are more toxic to the freshwater crustacean Daphnia pulex compared to bulk ZnO or ZnSO 4 ·7H 2 O. To provide an integrated and quantitative insights into the toxicity of ZnO NPs, we conducted isobaric tags for relative and absolute quantitation (iTRAQ) proteomic analysis, which detected 262, 331, and 360 differentially expressed proteins (DEPs) in D. pulex exposed to ZnO NPs, bulk ZnO, and ZnSO 4 ·7H 2 O, respectively. Among the DEPs, 224 were shared among the three treatments. These proteins were related to energy metabolism, oxidative stress, and endoplasmic reticulum stress. The three forms of Zn all caused D. pulex to downregulate Chitinase expression, disrupt Ca 2+ homeostasis, and reduce expression of digestive enzymes. Nevertheless, 29 proteins were expressed only in the ZnO NP treatment. In particular, histone (H3) and ribosomal proteins (L13) were obviously influenced under ZnO NP treatment. However, increased expression levels of h3 and l13 genes were not induced only in ZnO NP treatment, they were sensitive to Zn ions under the same exposure concentration. These results indicate that the three zinc substances have a similar mode of action and that released zinc ions are the main contributor to ZnO NP toxicity to D. pulex under a low concentration. Further investigation is needed to clarify whether a small proportion of DEPs or higher bioavailability cause ZnO NPs to be more toxic compared to bulk ZnO or ionic zinc.

A facile and sensitive method for the quantitative detection of telomerase and in situ imaging of intracellular telomerase is developed by using a graphene oxide (GO)-based fluorescent nanosensor. The nanosensor consists of a fluorescent DNA (P1) adsorbed on the GO surface. Here, GO serves not only as a fluorescence quencher but also as a carrier to successfully transport P1 into cancer cells as a signal reporter. P1 is a dye-labeled single-stranded DNA complementary to the telomeric repeated sequence, and initially the combination of P1 and GO exhibits minimal background fluorescence. When telomerase extends its repeat units of TTAGGG on the 3'-end of the primer-DNA, the fluorescence of P1 is subsequently recovered because the telomeric repeated sequence can hybridize with P1 and liberate it from the GO surface. This method enables the determination of telomerase activity down to 10 cells. For the in situ detection of telomerase, upon endocytosis of the P1/GO combinatorial probe into living cancer cells, the intracellular telomerase extends its primer to produce the telomeric repeated sequence and then turns on the fluorescence of P1, which can be directly monitored by confocal laser scanning microscopy. The feasibility of the assay is further investigated by treating with telomerase-related drugs, and the results demonstrate its potential in antitumor drug screening and cancer therapy evaluation.

A bimetal lanthanide coordination polymer nanoparticle (ATP-Ce/Tb-Tris CPNs) with good biocompatibility was synthesized in Tris-HCl buffer using adenosine triphosphate (ATP) molecules as the bridge ligands. The large absorption cross section and suitable emission energy of Ce 3+ matching to the adsorption energy of Tb 3+ ( 4 f n ) results in the efficient energy transfer from Ce 3+ to Tb 3+ , thus the synthesized ATP-Ce/Tb-Tris CPNs exhibit the characteristic green emission of Tb 3+ . Such energy transfer from metal to metal in fluorescent lanthanide coordination polymer nanoparticles (Ln-CPNs) has been demonstrated. It is found that the oxidation of Ce 3+ in ATP-Ce/Tb-Tris CNPs to Ce 4+ would interrupt the energy transfer from Ce 3+ to Tb 3+ , leading to fluorescence quenching of Tb 3+ . On the basis of this quenching mechanism, ATP-Ce/Tb-Tris CPNs has been successfully used to detect reactive oxygen H 2 O 2 with detection limit as low as 2nM. If glucose oxidase is present in the system, glucose can be determined using the ATP-Ce/Tb-Tris CNPs nanosensor., (Copyright © 2016 Elsevier B.V. All rights reserved.)

A facile approach for preparation of molecularly imprinted polymers was developed and successfully used as chiral stationary phase for rapid enantioseparation by open tubular capillary electrochromatography (OT-CEC). In this work, molecularly imprinted polymers were one-step prepared employing Fe3O4 nanoparticles (NPs) as the supporting substrate and dopamine as the functional monomer. By simply mixing Fe3O4 NPs with template molecules in a weak alkaline solution of dopamine, a thin adherent polydopamine (PDA) film imprinted with template molecules was formed by the self-polymerization of dopamine on the surface of Fe3O4 NPs. After extracting the embedded template molecules, the produced imprinted Fe3O4@PDA NPs are of three dimensional shape of template molecules favoring high binding capacity and magnetism property for easy manipulation. The imprinted Fe3O4@PDA NPs prepared with l-tryptophan, l-tyrosine, Gly-l-Phe or s-ofloxacin as template molecules were packed in the PDMS microchannel via magnetic field as novel stationary phase for the successful enantioseparation of corresponding target analysts. In addition, the imprinted Fe3O4@PDA NPs-based OT-CEC system exhibited excellent reproducibility, stability and repeatability, which provides a powerful protocol for separation enantiomers within a short analytical time and opens up a promising avenue for high-throughput screening of chiral compounds., (Copyright © 2014 Elsevier B.V. All rights reserved.)

A novel experimental methodology based on the unique characteristics of chitosan-branched ferrocene (CS-Fc) and gold nanoparticles (Au NPs) was developed to design a label-free amperometric immunosensor for the sensitive detection of hepatitis B surface antigen (HBsAg) as a model protein. The controllable electrodeposition of CS-Fc solution formed a three-dimensional robust film with good biocompatibility and large surface area for the assembly of Au NPs and further immobilization of hepatitis B surface antibody (HBsAb) on an electrode. The morphologies and electrochemistry of the formed nanocomposite biofilm were investigated by using scanning electron microscopy and electrochemical techniques including cyclic voltammetry and electrochemical impedance spectroscopy, respectively. The HBsAg concentration was measured through the decrease of amperometric responses in the corresponding specific binding of antigen and antibody. The decreased differential pulse voltametric values were proportional to the HBsAg concentration in the range of 0.05-305ngmL(-1) with a detection limit 0.016ng. This would provide an approach for the application of mediator in immunoassays.

In this paper, titanium dioxide nanoparticles (TiO(2) NPs) were employed to construct a functional film on PDMS microfluidic channel surface, which was formed by sequentially immobilizing poly(diallyldimethylammonium chloride) and TiO(2) NPs on PDMS surface by layer-by-layer assembly technique. The modified PDMS microchip exhibited a decreased and stable EOF, which was favorable for the separation of biomolecules with similar migration times. Arginine, phenylalanine, serine and threonine were used as model analytes to evaluate the performance of the modified microchip. The four amino acids were efficiently separated within 100 s in a 3.7 cm long separation channel and successfully detected on the carbon fiber electrode in conjunction with in-channel indirect amperometry. Resolutions and theoretical plate numbers of the analytes were considerably enhanced in the presence of TiO(2) NPs. The modified microchip demonstrated excellent stability and reproducibility with improved RSDs of migration times and peak currents for run-to-run, day-to-day and chip-to-chip analyses, respectively. Variables influencing the separation efficiency and amperometric response, including injection and separation voltage, the working electrode position and buffer concentration, were optimized in detail.

A novel dopamine sensor was fabricated by forming the 6-ferrocenylhexanethiol (HS(CH(2))(6)Fc) functionalized Fe(3)O(4)@Au nanoparticles (NPs) films on the surface of a carbon paste electrode with the aid of a permanent magnet. HS(CH(2))(6)Fc, which acted as the redox mediator, was self-assembled to Fe(3)O(4)@Au NPs via Au-S bond. Transmission electron microscopy, UV-visible absorption spectroscopy, Fourier transform infrared spectra, and cyclic voltammetry were used to characterize the properties of the Fe(3)O(4)@Au NPs/HS(CH(2))(6)Fc nanocomposite. It is shown that the prepared ferrocene-functionalized Fe(3)O(4)@Au NPs composite shuttled electrons between analyte and electrode, increased the mediator loading, and more importantly prevented the leakage of the mediator during measurements, which resulted in the substantially enhanced stability and reproducibility of the modified electrode. The electrooxidation of dopamine could be catalyzed by Fc/Fc(+) couple as a mediator and had a higher electrochemical response due to the unique performance of Fe(3)O(4)@Au NPs. The nanocomposite modified electrode exhibited fast response (3 s) and the linear range was from 2.0x10(-6) to 9.2x10(-4) M with a detection limit of 0.64 microM. This immobilization approach effectively improved the stability of the electron transfer mediator and is promising for construction of other sensors and bioelectronic devices.

Au nanoparticles modified with electroactive Prussian blue (PB) were for the first time synthesized by a simple chemical method. Transmission electronic microscopy showed that the average size of the Prussian blue shell/Au core hybrid composite (PB@Au) was about 50 nm, and Fourier transform IR, UV-vis spectra, and cyclic voltammetry confirmed the existence of PB on the surface of Au nanoparticles. Using the LbL technique, multilayer thin films of PB@Au nanoparticles were prepared by the alternate adsorption of oppositely charged linear polyelectrolyte poly(allylamine hydrochloride) (PAH) onto ITO glass for the construction of a hydrogen peroxide sensor. The novel multilayer films were characterized by SEM, cyclic voltammetry, and UV-visible absorption spectroscopy. The {PAH/PB@Au}n multilayer-modified electrode showed a well-defined pair of redox peaks and dramatic catalytic activity toward the reduction of hydrogen peroxide.

A fluorometric method is described for the determination of thrombin. Polymer nanoparticles containing the luminol-terbium(III) complex (luminol-Tb) were prepared where luminol acts as the bridging ligand, and Tb(III) acts as the central metal ion. Thrombin possesses a large number of electrons donating groups that coordinate with luminol-Tb. Following coordination, the rigidity of the linker is increased, and this decreases the non-radiative decay rate and induces an increase in fluorescence intensity at 430 nm. Hence, thrombin can be fluorometrically determined. The detection limit of thrombin is as low as 3.5 pM (at an SNR of 3). This is about 10 times lower than assays using an aptamer. The method was applied in the determination of thrombin in human serum via the standard addition method and gave satisfying results. [ABSTRACT FROM AUTHOR]

We report on the refractive index change in Au3+-doped silicate glasses irradiated by a femtosecond laser and successive heat treatment. The refractive index of the irradiated area increased after the femtosecond laser irradiation and decreased with increasing annealing temperature up to 450 °C and then increased again with increasing annealing temperature. Absorption spectra of the glass samples before and after femtosecond laser irradiation and after further annealing manifested the formation of color centers after laser irradiation, disappearance of color centers after annealing at 300 °C, and precipitation of gold nanoparticles after annealing at high temperature. The mechanisms of the observed phenomena are discussed. [ABSTRACT FROM AUTHOR]

“Free” arsenite sensor: Based on the principle that G‐/T‐rich single‐stranded DNA (ssDNA) and folded DNA bound to arsenite have different propensities to adsorb onto Au nanoparticles (Au NPs) in colloidal solution, a label‐free colorimetric assay for arsenite sensing based on color changes associated with the aggregation of Au NPs has been designed (see scheme). [ABSTRACT FROM AUTHOR]

Polypropylene (PP)/C60 nanocomposites with improved interfacial interaction were prepared via in situ melt radical reaction. It was found that the relaxation time of PP/C60 nanocomposites containing peroxide increased due to the reaction between C60 and PP macroradicals and the formation of long chain branched or crosslinking structure. Thermogravimetric analysis (TGA) results showed that the thermal stability of PP/C60 nanocomposites was enhanced. The initial decomposition temperatures and activation energy of PP/C60 nancomposites were strongly influenced by the content of unreacted C60. Because of the improved interfacial interaction, PP/C60 nanocomposites containing peroxide showed obvious increase in tensile strength, Young' modulus, flexural strength, flexural modulus, and impact strength, compared to PP/C60 nanocomposites (without peroxide) containing the same content of C60. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

n amperometric immunosensor has been developed for sensitive determination of hepatitis B surface antigen as a model protein. A glassy carbon electrode was modified with an assembly of positively charged poly(allylamine)-branched ferrocene (PAA-Fc) and negatively charged gold nanoparticles (Au NPs). The formation of PAA-Fc effectively avoids the leakage of Fc, retains its electrochemical activity, and enhances the conductivity of the composite. The adsorption of Au NPs onto the PAA-Fc matrix provides sites for the immobilization of the antigen and a favorable micro-environment to maintain its activity. The morphologies and electrochemistry of the sensing film were investigated via scanning electron microscopy, electrochemical impedance spectroscopy, and cyclic voltammetry. Factors influencing the performance of the immunosensor were studied in detail. The concentration of the antigen can be quantitated (by measuring the decrease of the amperometric response resulting from the specific binding between antigen and antibody) in the range between 0.1 and 150 ng mL, with a detection limit of 40 pg mL (S/N = 3). The method is economical, efficient, and potentially attractive for clinical immunoassays. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

This paper studies the photosensitive effect of cerium oxide on the precipitation of Ag nanoparticles after femtosecond laser irradiating into silicate glass and successive annealing. Spectroscopy analysis and diffraction efficiency measurements show that the introduction of cerium oxide may increase the concentration of Ag atoms in the femtosecond laser-irradiated regions resulting from the photoreduction reaction Ce3+ + Ag+ - Ce4+ + Ag0 via multiphoton excitation. These results promote the aggregation of Ag nanoparticles during the annealing process. It is also found that different concentrations of cerium oxide may influence the Ag nanoparticle precipitation in the corresponding glass. [ABSTRACT FROM AUTHOR]

Abstract: A simple and controllable electrodeposition method is described to fabricate a homogeneous chitosan-ferrocene/Au nanoparticles/glucose oxidase (CS-Fc/Au NPs/GOx) nanocomposite film. The morphologies and electrochemistry of the nanocomposite film were investigated by using scanning electron microscopy (SEM) and electrochemical techniques including electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), respectively. The ferrocene group (Fc) covalently bounded chitosan hybrid (CS-Fc) can effectively avoid the leakage of Fc and retain its electrochemical activity. Further immobilization of Au NPs into the CS-Fc matrix enhances both the charge-transport properties of the composite and bioaffinity to enzyme. Biosensor based on this CS-Fc/Au NPs/GOx film has advantages of fast response, excellent reproducibility and high stability. This biosensor shows a linear response to glucose in the concentration range from 0.02 to 8.66mM with a detection limit of 5.6μM at a signal-to-noise ratio of 3. The present method offers a facile way to fabricate biosensors and bioelectronic devices. [Copyright &y& Elsevier]

The influence of oleic acid modified Fe 3 O 4 (OA-Fe 3 O 4 ) nanoparticles on the morphology and foaming behavior of cocontinuous linear low density polyethylene/polystyrene (LLDPE/PS) immiscible blends (60/40 by weight) was studied. The morphology observation showed that the addition of nanofillers resulted in the increased dispersion degree of both LLDPE and PS components and even the transformation of phase structure from cocontinuous structure to sea-island structure, when enough amounts of nanoparticles were added. Meanwhile the introduction of enough amounts of OA-Fe 3 O 4 nanoparticles effectively enhanced the foaming ability of LLDPE/PS blend at semi-solid state during scCO 2 batch foaming. The mechanism analysis for the change of foaming behavior showed that the improved foaming capacity resulted from the change of the phase structure of LLDPE/PS blends and heterogeneous nucleation of OA-Fe 3 O 4 nanofillers. Sorption and desorption measurements showed that the addition of OA-Fe 3 O 4 nanoparticles in the LLDPE/PS blend increased the solubility of CO 2 , and the presence of enough amount of OA-Fe 3 O 4 decreased the desorption rate of CO 2 in the initial period of depressurization process, which are beneficial to cell nucleation and growth. Furthermore, it was found that the melt behavior and crystalline properties of LLDPE/PS blends were not the key factors to improved foaming behavior of the blends in the presence of OA-Fe 3 O 4 nanoparticles. [ABSTRACT FROM AUTHOR]

We experimentally studied the diffusive dynamics of polystyrene nanoparticles in a flashing optical field using coaxial differential dynamic microscopy. When using a chopper to generate a periodic optical field from a semiconductor laser, we observed the oscillatory motion, which reduced the effective diffusion coefficient of the nanoparticles, making it smaller than that in a continuous optical field (reaching a minimum at a fixed frequency of 2400 Hz). Moreover, the diffusion of the nanoparticles slowed as the laser power increased in the flashing optical field. Our experimental results not only facilitated our understanding of the diffusion of nanoparticles in complex optical fields but also paved the way for potential applications in optical micromanipulation and atom cooling. • Experimental study of the diffusive dynamics of nanoparticles in a flashing optical field. • The diffusion of the nanoparticles in a flashing optical field was slower than that in a continuous optical field, and both slowed as increasing the laser power. • Due to the stochastic resonance, the effective diffusion coefficients of nanoparticles reach a minimum value at the frequency of 2400 Hz. [ABSTRACT FROM AUTHOR]

Abstract: In this study, magnetic core–shell Fe3O4@Al2O3 nanoparticles (NPs) attached to the surface of a magnetic glassy carbon electrode (MGCE) were used as a functional interface to immobilize several heme proteins including hemoglobin (Hb), myoglobin (Mb) and horseradish peroxidase (HRP) for fabricating protein/Fe3O4@Al2O3 film. Transmission electron microscope, UV–vis spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry were used to characterize the films. With the advantages of the magnetism and the excellent biocompatibility of the Fe3O4@Al2O3 NPs, the protein/Fe3O4@Al2O3 film could be easily fabricated in the present of external magnetic field, and well retained the bioactivity of the immobilized proteins, hence dramatically facilitated direct electron transfer of heme proteins and excellent electrocatalytic behaviors towards H2O2 were demonstrated. The presented system avoids the complex synthesis for protecting Fe3O4 NPs, supplies a facile, low cost and universal way to immobilize proteins, and is promising for construction of third-generation biosensors and other bio-magnetic induction devices. [ABSTRACT FROM AUTHOR]

We present a symmetric electrophoretic light scattering measurement method for the determination of the zeta potential of colloidal systems. In contrast to the traditional method, where a detector probes the light from one scattering point and a reference, this method takes two symmetrical points at the vertical arms on both sides of a u-shaped sample pool as detection points, where the magnitude of the speed of the particles is almost the same except that the directions are opposite. We derive the light intensity autocorrelation function, and observe that the frequency of the signal for the velocity measurement is doubled, which results in a high signal-to-noise ratio. We set up a double scattered optical arrangement and the experimental results demonstrate that the symmetric measurement method has a better accuracy, sensitivity and repeatability than those of the traditional method. It is expected that this symmetric measurement method will improve the determination of the zeta potential of colloidal systems. [ABSTRACT FROM AUTHOR]

Abstract As(III) is the most harmful substance of all over 20 kinds of arsenic compounds. In addition, the trivalent oxidation state of arsenic is not stable, which can be oxidized to pentavalent arsenic. Thus, it is attractive and challenging to sensitively and selectively monitor As(III) concentration, rather than As(V) concentration, in water. However, most of detection techniques suffer from the inability to distinguish As(III) and As(V), or even need specialized personnel and additional equipment. Herein, novel luminescent Ce(III)-based coordination polymer nanoparticles (Ce-CPNs) have been proposed for selective detection of As(III). The Ce-CPNs are dispersive and show a fluorescence peak at 353 nm under excitation at 280 nm. With the presence of As(III), aggregation of Ce-CPNs occurs, resulting in quenching of the fluorescent Ce-CPNs due to the aggregation-caused π-π stacked layers of Ce-CPNs. Under optimal conditions, the detection limit for As(III) is down to 0.7 ppb. In addition, the Ce-CPNs are selective for As(III) over other ions and has been successfully applied for fluorescence sensing of As(III) in environmental water samples. Graphical abstract A novel As(III) fluorescence assay was proposed using Ce(III)-based coordination polymer nanoparticles (Ce-CPNs) fluorescent probes based on target induced aggregation of Ce-CPNs and the aggregation-caused π-π stacked layers of Ce-CPNs. fx1 Highlights • Ce(III)-based coordinate polymer nanoparticles (Ce-CPNs) were synthesized using a facile solvothermal method. • It is a novel strategy for the sensitive determination of As(III) based on the quenching of Ce-CPNs fluorescence. • Ce-CPNs fluorescent probe displayed outstanding detection capabilities for As(III) in environmental samples. [ABSTRACT FROM AUTHOR]

An electrochemical sensor was fabricated for arsenite detection using graphene oxide-assisted generation of prussian blue nanoparticles as enhanced redox signal label. The 5′-thiolate-labeled (GT) 21 -ssDNA was first self-assembled on a gold electrode surface via Au-S bond. Graphene oxide can interact with ssDNA through π-π stacking interaction and facilitate the generation of prussian blue nanoparticles on its surface as an electrochemically active indicator. In the absence of arsenite, plenty of graphene oxide/prussian blue nanoparticles can be adsorbed on the electrode surface to produce a stronger redox signal of prussian blue nanoparticles. While in the presence of arsenite, (GT) 21 -ssDNA can recognize and combine with arsenite via hydrogen bonds to form (GT) 21 -ssDNA/arsenite complex with a frizzy structure. The conformational change of (GT) 21 -ssDNA led to less adsorption of graphene oxide/prussian blue nanoparticles on the electrode surface, resulting in a reduced redox response. The arsenite-induced (GT) 21 -ssDNA structure switching can be used for sensitive detection of arsenite with a linear range from 0.2 to 500 ppb and a detection limit down to 0.058 ppb. Benefiting from (GT) 21 -ssDNA containing arsenite recognition sequence, the proposed sensor exhibited excellent specificity against other heavy metal ions. The applicability of the electrochemical biosensor for arsenite assay in real water samples demonstrated the great potential of this strategy for trace arsenite detection in environment. [ABSTRACT FROM AUTHOR]

A new strategy based on enzymatically engineered primer extension poly-thymine (EPEPT) and nanomaterials in situ generation technology is reported for direct detection of microRNA (miRNA) in a fluorescence turn-on format using the sequential and complementary reactions catalyzed by Klenow Fragment exo − (KFexo − ) and terminal deoxynucleotidyl transferase (TdTase). The short miRNA can be efficiently converted into long poly-thymine (polyT) sequences, which function as template for in situ formation of fluorescence copper nanoparticles (CuNPs) as nano-dye for detecting miRNA. The polyT-CuNPs can effectively form and emit intense red fluorescence under the 340 nm excitation. For the proof of concept, microRNA-21 (miR-21) was selected as the model target to testify this strategy as a versatile assay platform. By directly using miR-21 as the primer, the simple, rapid and sensitive miRNA detection was successfully achieved with a good linearity between 1 pM and 1 nM and a detection limit of 100 fM. Thus, the EPEPT strategy holds great potential in biochemical sensing research as an efficient and universal platform. [ABSTRACT FROM AUTHOR]

Abstract: Polypropylene/carbon black (PP/CB) nanocomposites were prepared by melt compounding to investigate the effect of nanofiller loadings on the thermal and flammability properties of PP. The obtained nanocomposites displayed not only dramatically enhanced thermal stability both under nitrogen and in air, but also improved flame retardancy to some extent. Moreover, the higher the loading level of CB, the better was the improved effect. This enhanced mechanism was attributed mainly to trapping of peroxy radicals by CB nanoparticles at elevated temperature to form a gelled-ball crosslinked network, which act as a barrier to both heat and mass transfer. The thermal-oxidation cross-linking reaction was supported by the results of rheological properties, gel measurements and FTIR analysis. [Copyright &y& Elsevier]

Abstract: In this study, bifunctional Fe3O4@ZrO2 magnetic core–shell nanoparticles (NPs), synthesized by a simple and effective sonochemical approach, were attached to the surface of a magnetic glassy carbon electrode (MGCE) and successfully applied to the immobilization/adsorption of myoglobin (Mb) for constructing a novel biosensor platform. With the advantages of the magnetism and the excellent biocompatibility of the Fe3O4@ZrO2 NPs, Mb could be easily immobilized on the surface of the electrode in the present of external magnetic field and well retained its bioactivity, hence dramatically facilitated direct electron transfer of Mb was demonstrated. The proposed Mb/Fe3O4@ZrO2 biofilm electrode exhibited excellent electrocatalytic behaviors towards the reduction of H2O2 with a linear range from 0.64μM to 148μM. This presented system avoids the complex synthesis for protecting Fe3O4 NPs, supplies a simple, effective and inexpensive way to immobilize protein, and is promising for construction of third-generation biosensors and other bio-magnetic induction devices. [Copyright &y& Elsevier]