Search

Metal oxide semiconductors have been proven to be a very effective photocatalytic material. In this study, Au-WO3 was successfully synthesized through a microwave irradiation-assisted one-pot method. The results demonstrated that the hydration degree of WO3·nH2O could be controlled by Au, and the nanorods could be refined. When the optimum Au modification level was 5.4 wt.%, the specific surface area of WO3·nH2O increased from 36.67 m2 g−1 to 71.72 m2 g−1, indicating that active sites on the catalyst surface were added. The photocatalytic degradation of rhodamine B (RhB) is considered to assess the photocatalytic performance of the Au-WO3 nanoparticles under visible light. The deterioration of the sample increased initially, then decreased as the Au level increased. The photocatalytic degradation capacity was strongest when the Au content was 5.4 wt.%, and the degradation rate was 0.0084 min−1. [ABSTRACT FROM AUTHOR]

Though nanomaterials based on carbon have been widely used for the preparation of high-performance polymeric nanocomposites, there are few works focused on the effect of carbon nanoparticle morphology on the performance of corresponding polymer nanocomposites. Therefore, four representative carbon nanoparticles, including fullerene, carbon nanotubes, graphene, and carbon black incorporated poly(styrene-b-isoprene-b-styrene) (SIS) elastomer nanocomposites were fabricated using the solvent casting method. In addition, the effect of carbon nanoparticle morphology on the rheological, mechanical, electrical, and thermal properties of the obtained polymeric nanocomposites was systematically investigated. The results showed that the shape of carbon nanoparticles has a different effect on the properties of the obtained elastomer nanocomposites, which lays the foundation of carbon nanoparticle screening for high-performance polymer nanocomposite construction. [ABSTRACT FROM AUTHOR]

Developing efficient electrocatalysts for the oxygen reduction reaction (ORR) based on non‐precious catalytic centers is critical to improve the efficiency of low temperature fuel cells. Herein, we report on a catalyst containing CoSe2 supported on selenium decorated reduced graphene oxide (CoSe2/Se‐rGO), which was synthesized via a one‐pot solvothermal method using Se‐rGO as support. Importantly, the CoSe2/Se‐rGO showed an enhanced catalytic activity for ORR in alkaline medium with an onset potential of 0.903 V vs. RHE and a half‐wave potential of 0.803 V vs. RHE. Its stability and methanol tolerance ability were significantly improved as compared to 20 wt% Pt/C, respectively. The strategy developed here provided a novel and efficient approach to prepare non‐precious electrocatalysts for ORR. Uniform dispersion: Selenium decorated reduced graphene oxide supported cobalt selenide CoSe2/Se‐rGO is synthesized by a one‐pot solvothermal route. Selenium on the surface of rGO acts as a nucleation site, inducing the uniform dispersion of CoSe2 on the surface of graphene. The electrocatalytic performance for oxygen reduction reaction (ORR) in alkaline medium is enhanced. [ABSTRACT FROM AUTHOR]

Abstract: Exosomes, naturally derived nanovesicles secreted from various cell types, can serve as an effective platform for the delivery of various cargoes, because of their intrinsic ability such as long blood circulation and immune escapinge. However, unlike conventional synthetic nanoparticles, drug release from exosomes at defined targets is not controllable. Moreover, endowing exosomes with satisfactory cancer‐targeting ability is highly challenging. Here, for the first time, a biological and synthetic hybrid designer exosome is described with photoresponsive functionalities based on a donor cell‐assisted membrane modification strategy. Practically, the designer exosome effectively accumulates at target tumor sites via dual ligand‐mediated endocytosis. Then the localized hyperthermia induced by the conjunct gold nanorods under near‐infrared irradiation impacts the permeability of exosome membrane to enhance drug release from exosomes, thus inhibiting tumor relapse in a programmable manner. The designer exosome combines the merits of both synthetic materials and the natural nanovesicles. It not only preserves the intrinsic functionalities of native exosome, but also gains multiple abilities for efficient tumor targeting, controlled release, and thermal therapy like synthetic nanocarriers. The versatile designer exosome can provide functional platforms by engineering with more multifarious functionalities from synthetic materials to achieve individualized precise cancer therapy in the future. [ABSTRACT FROM AUTHOR]

Iridium nanoparticles (IrNPs) with intrinsic oxidase-like activity were synthesized by using sodium citrate as the stabilizer and NaBH as the reducing agent. The IrNPs have an average diameter of 2.5 ± 0.5 nm and exhibit excellent oxidase-like property. Under the catalytic action of the IrNPs, 3,3′,5,5′-tetramethylbenzidine (TMB) is oxidized by dissolved oxygen (DO) to form a blue product with an absorption maximum at 652 nm. The catalytic activity is ascribed to the production of superoxide anion radical (Oˉ∙). The chromogenic reaction is exploited for the determination of DO. The method exhibits a wide calibration range from 12.5 to 257.5 μM of DO and a limit of detection as low as 4.7 μM. Compared to other methods, this method presented here shows improved precision and faster response time. [ABSTRACT FROM AUTHOR]

Ruthenium (Ru) featured with an unusual catalytic behavior is of great significance in several heterogeneous and electro-catalytic reactions. The preparation of tractable Ru nanocatalysts and the building of highly active catalytic system at ambient temperature remains a grand challenge. Herein, a facile strategy is developed for the controllable preparation of Ru nanoparticles (NPs) with the sizes ranging from 2.6 to 51.5 nm. Ru NPs show superior size-dependent catalytic performance with the best kinetic rate constant as high as −1.52 min −1 , which could far surpass the other traditional noble metals. Ru NPs exert exceedingly efficient low-temperature catalytic activity and good recyclability in the catalytic reduction of nitroaromatic compounds (NACs) and azo dyes. The developed catalytic system provides a distinguishing insight for the artificial preparation of Ru NPs with desired sizes, and allows for the development of rational design rules for exploring catalysts with superior catalytic performances, potentially broadening the applications of metallic NP-enabled catalytic analysis. [ABSTRACT FROM AUTHOR]

A significant energy loss results from the poor thermal insulations of the commercial and public buildings. Windows diffuse a large fraction of building heating and cooling energy to the external environment, representing an annual impact of 4.1 quadrillion British thermal unit of primary energy in the US. The current technology for efficient windows relies upon the double-pane insulated glass unit with an insulating gas in between. A key challenge is to reduce thermal conductivity of the windows without relying on insulating materials. The photothermal effect can be possibly utilized for particular functionalities that can collect solar energy for reducing heat loss. The insulation efficiency is quantified through the U-factor, defined as the ratio of the heat flux ( H) per unit area through the pane to the difference (Δ T) between the window interior surface and exterior temperatures. Upon solar irradiation, single-panes can “self-heat” via the photothermal effect from the nanoparticle coatings. This can effectively reduce Δ T for enhanced thermal insulation. In this study, the photothermal effect on Fe 3 O 4 nanoparticles stimulated by solar light was investigated for nanoparticles in solutions and as thin films for energy–efficient windows. The Fe 3 O 4 nanoparticles were surface-functionalized with different polymers to modulate colloidal stability and for the investigation of the photothermal effect. The photothermal heating efficiencies of Fe 3 O 4 with different surface coatings were found to be much greater under the white-light irradiation than near infrared (NIR) in both aqueous suspension and as thin films. The mechanism for the photothermal effect of Fe 3 O 4 was identified in terms of its band structure. Both Urbach energy and band gap were obtained based on absorption spectra of various Fe 3 O 4 nanoparticles. The Urbach “tail” was found consistent with nanoparticle surface defect structures, while the band gap (~3.1 eV) corresponded to the electronic transitions in the octahedral site of Fe 3 O 4 . We also discuss the absorption-based photonic physics responsible for the much-enhanced photothermal heating by white-light as compared with NIR. Based on the photothermal heating, the U-factors were obtained with the nanoparticle coatings that show promise in producing energy efficient windows. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate the efficacy of paclitaxel combined with curcumin (CUR) against drug resistance in ovarian cancer cells. PLGAphospholipid-PEG nanoparticles were prepared using the nano precipitation method. The size and morphology of the nanoparticles were determined using a transmission electron microscope and particle size analyzer. The encapsulation efficiency of nanoparticles was determined using the ultrafiltration centrifugation method. The dialysis method was used to study the release of PLGA-phospholipid-PEG nanoparticles. ADM was used to induce the A2780 cell line (human ovarian cancer cell line) to establish the model of the multidrug-resistant (MDR) cell line, and the protein activity of P-glycoprotein (P-gp) in the A2780 cell line and A2780/ ADM resistant cell line was determined using western blot analysis. The results showed that, the prepared nanoparticles were uniform in size, with a size of approximately 100 nm, and round in shape. Additionally, the nanoparticles had a more gentle and slow release than the free drug release. The results of the protein trace printing experiment showed that the P-gp content of the drug-resistant cell line was significantly reduced by the CUR nanoparticles. In conclusion, PLGA-phospholipid nanoparticles containing taxol and CUR have improved solubility and stability together with a slow release effect. In addition, CUR was able to overcome the MDR of tumor cells by elevating the paclitaxel concentration in the tumor cells to improve the antitumor activity of this combination. [ABSTRACT FROM AUTHOR]

Magnetic fluorescent nanoparticles (NPs) have great potential applications for diagnostics, imaging and therapy. We developed a facile polyol method to synthesize multifunctional Fe3O4@CeF3:Tb@CeF3 NPs with small size (＜20 nm), high water solubility and good biocompatibility. The NPs were modified by ligand exchange reactions with citric acid (CA) to obtain carboxyl-functionalized NPs (Fe3O4@CeF3:Tb@CeF3–COOH). Folic acid (FA) as an affinity ligand was then covalently conjugated onto NPs to yield Fe3O4@CeF3:Tb@CeF3–FA NPs. They were then applied as multimodal imaging agents for simultaneous in vitro targeted fluorescence imaging and magnetic resonance imaging (MRI) of HeLa cells with overexpressed folate receptors (FR). The results indicated that these NPs had strong luminescence and enhanced T2-weighted MR contrast and would be promising candidates as multimodal probes for both fluorescence and MRI imaging. [ABSTRACT FROM AUTHOR]

The materials encapsulated within oil-in-water emulsions are prone to oxidation due to the permeation of oxidative species across the oil–water interface and into the lipid phase. Thus, the oxidative barrier properties of the interfacial layer are pivotal in reducing oxidation within emulsified oils. To enhance these barrier properties, we explored an approach of stabilizing emulsions using ‘silica–polymer microparticles’. We hypothesize that these microparticles will enhance the barrier properties of emulsion interfaces by mechanisms such as higher interfacial thickness and quenching of oxidative species before they permeate into the emulsions. Silica–ε-polylysine (Si–EPL) microparticles were synthesized by electrostatic aggregation of anionic silica nanoparticles and cationic ε-polylysine in the aqueous phase. Formation of Si–EPL microparticles was validated using particle size, ζ-potential and scanning electron microscopy measurements. These microparticles were subsequently used for emulsion stabilization. Emulsions stabilized by silica nanoparticles alone were used as control. Oxidative barrier properties were determined by measuring the rate of permeation of peroxyl radicals from the aqueous to the oil phase of the emulsion using fluorescence based methods. The rate of permeation of peroxyl radicals was significantly lower in emulsions stabilized by Si–EPL microparticles compared to that stabilized by silica nanoparticles. One of the mechanisms responsible for the observed effect was enhanced quenching of peroxyl radical by Si–EPL microparticles before they can permeate inside the oil phase. To further validate the results, stability of a model bioactive compound, retinol, encapsulated in these emulsions was compared. Consistent with peroxyl radical permeation measurements, emulsion stabilized by Si–EPL microparticles significantly improved the oxidative stability of retinol compared to that stabilized by silica nanoparticles alone. Thus, by engineering the physical properties of the interfacial layers, the oxidation of the encapsulants in emulsions can be controlled. [ABSTRACT FROM AUTHOR]

DNA extraction is always an important and key step in bioanalytical fields for target nucleic acid detection. Traditional organic solvent-based extraction methods are toxic and time-consuming. In this work, we report a systematic study of magnetic nanoparticles (MNPs) as probes for genomic DNA extraction from genetically modified organism (GMO) plants. Different surface-functionalised MNPs with controllable diameters have been used to extract the genomic DNA directly from GMO plants for detections. Systematic comparison of the results obtained under different extraction conditions has indicated that carboxyl-modified MNPs with smaller diameters are more suitable for genomic DNA extractions. The successful qualitative detection of GMO and non-GMO products based on the MNP extracted DNA is also achieved and discussed in this article. In view of the advantages of magnetic extraction, such as nontoxicity, ease of operation, and rapid and high throughput, this systematic research has demonstrated the great potential of the method and provides theoretical guidance for practical MNP applications. [ABSTRACT FROM AUTHOR]

Structure properties of silicone oil serving as a liquid substrate exposed to Ar plasma are investigated in this paper. Under the action of energetic Ar ions, the surface of silicone oil liquid substrate exhibits a branch-like fractal aggregation structure, which is related to the structure evolution of silicone oil liquid from Si-O chain to Si-O network. The radicals from the dissociation of silicone oil molecule into the Ar plasma turns the plasma into a reactive environment. Therefore, the structural evolution of silicone oil liquid substrate and the reactive radicals in the plasma space become possible factors to affect the aggregation of nanoparticles and also the structures and the compositions of nanoparticles. [ABSTRACT FROM AUTHOR]

A biosensor for hydrogen peroxide was fabricated by co-immobilizing cadmium telluride (CdTe) nanoparticles, chitosan, and hemoglobin (Hb) matrix. There was a pair of nearly reversible redox peaks around -0.360 V, and the electrochemical behavior of Hb was a surface-controlled process, with an electron-transfer rate constant of 1.36 s-1 and surface coverage of 2.62 × 10-10 mol cm-2. Fourier transform infrared (FT-IR) spectra and ultraviolet-visible (UV-vis) spectra indicated that Hb sustained its natural conformation. It was demonstrated that Hb in the matrix kept its bioactivity and exhibited catalytic ability toward H2O2, with a response ranging from 7.44 × 10-6 to 6.95 × 10-4 M and a detection limit of 2.23 × 10-6 M. [ABSTRACT FROM AUTHOR]

Here, we report a simple fluorescent strip sensor based on aptamer–quantum dots technology that can meet toxin monitoring demands using ochratoxin A (OTA) as a model toxin. The limit of the detection (LOD) for the fluorescent strip was 1.9 ng mL−1, while the time needed for the detection is only 10 min; this conforms to the standards of World Health Organization (WHO) or better. Overall functional parameters are also better than the analogous characteristics of gold nanoparticle strips.High selectivity was maintained as well, making them suitable for the samples with complex solution composition. [ABSTRACT FROM AUTHOR]

• Electrochemical ratiometric sensor is proposed for the detection of PSA. • Electroactive Ag nanodots are leached through resorcinol-formaldehyde surface. • Electroactive Cu 2 O NPs were designed to grow on rGO/Fe 3 O 4 NSs. • Electroactive Ag NPs and Cu 2 O NPs are detection and reference tags. • Electrochemical sensor achieves the accurate detection of PSA. Early detection of prostate specific antigen (PSA) could reduce the mortality from prostate cancer. Electroactive nanostructures have attracted much attention due to their excellent electronic conductivity and favorable biological microenvironment. In particular, electroactive Cu 2 O nanoparticles (NPs) and Ag NPs exhibited unique oxidation signals at around -0.1 V and +0.2 V. The separated and non-interfere oxidation signals enabled them to be alternative electrochemical beacons for the establishment of ratiometric electrochemical sensor for PSA detection. Electroactive Cu 2 O NPs were designed to grow on the surface of reduced graphene oxide/Fe 3 O 4 nanosheets (rGO/Fe 3 O 4 NSs) and served as reference tags due to the stable differential pulse voltammetry (DPV) signals of Cu 2 O NPs, magnetic properties for the absorption on electrode and the accelerated electron transfer ability of rGO. In order to improve the sensitivity of detection, a large number of small electroactive Ag nanodots were dispersed on the surface of Ag@resorcinol-formaldehyde (RF) NPs and served as detection tags. Electroactive Ag@RF-Ag NPs were assembled with rGO/Fe 3 O 4 /Cu 2 O NSs for the fabrication of ratiometric electrochemical aptasensor. With the addition of PSA, aptamers modified Ag@RF-Ag NPs disassembled from electrode surface, resulting in the decrease of DPV signals near +0.2 V and unchanged DPV signals at -0.1 V. This developed ratiometric electrochemical aptasensor achieved sensitive and accurate PSA detection. This proposed ratiometric electrochemical aptasensor has the advantages of easy preparation, simple structure and wide detection ranges. [ABSTRACT FROM AUTHOR]

Even after more than two decades of intense studies, the research on self‐assembly processes involving supramolecular interactions between nanoparticles (NPs) is continuously expanding. Plasmonic NPs have attracted particular attention due to strong optical, electrical, biological, and catalytic effects they are accompanied with. Surface plasmon resonance characteristics of plasmonic NPs and their assemblies enable fine‐tuning of these effects with unprecedented dynamic range. In turn, the uniquely high polarizability of plasmonic nanostructures and related optical effects exemplified by surface‐enhanced Raman scattering and red–blue color changes give rise to their application to biosensing. Since supramolecular interactions are ubiquitous in nature, scientists have found a spectrum of biomimetic properties of individual and assembled NPs that can be regulated by the layer of surface ligands coating all NPs. This paradigm has given rise to multiple studies from the design of molecular containers and enzyme‐like catalysts to chiroplasmonic assemblies. Computational and theoretical advances in plasmonic effects for geometrically complex structures have made possible the nanoscale engineering of NPs, assemblies, and supramolecular complexes with biomolecules. It is anticipated that further studies in this area will be expanded toward chiral catalysis, environmental monitoring, disease diagnosis, and therapy. [ABSTRACT FROM AUTHOR]

Probe bismuth sulfide modified with Pluronic F127 (Bi2S3-PF127), which has high biocompatibility and dispersibility, is synthesized using triblock copolymer Pluronic F127 to modify hydrophobic Bi2S3 nanoparticles that are prepared by a hot injection method. TEM results show that most of the probe has a length of about 14.85 ± 1.70 nm and a breadth of about 4.79 ± 0.63 nm. After injected into the tail vein of a mouse, the probe has obvious CT contrast enhancement capability from x-ray CT imaging results. Meanwhile, the probe’s in vivo toxicity is also studied. It is found that hematoxylin and eosin stains of major organs have no change. A biochemical analysis (alanine aminotransferase and aspartate aminotransferase) prove the probe has no adverse effects. The results of a blood analysis (white blood cell count, red blood cell count, hemoglobin, and platelet count) are also normal. The biological distribution of Bi by ICP-AES shows that most of nanoparticles are cleaned out after injection 48 h, and the circulation half-life of the probe is 5.0 h, suggesting that Bi2S3-PF127 has a long circulation and indicating that the Bi2S3-PF127 probe has good biocompatibility and safety. [ABSTRACT FROM AUTHOR]

Incorporating ligands with nanoparticle-based carriers for specific delivery of therapeutic nucleic acids (such as antisense oligonucleotides and siRNA) to tumor sites is a promising approach in anti-cancer strategies. However, nanoparticle-based carriers remain insufficient in terms of the selectivity and transfection efficiency. In this paper, we designed a dual receptor–targeted QDs gene carrier QD-(AS-ODN+GE11+c(RGDfK)) which could increase the cellular uptake efficiency and further enhance the transfection efficiency. Here, the targeting ligands used were peptides GE11 and c(RGDfK) which could recognize epidermal growth factor receptors (EGFR) and integrin ανβ3 receptors, respectively. Quantitative flow cytometry and ICP/MS showed that the synergistic effect between EGFR and integrin ανβ3 increased the cellular uptake of QDs carriers. The effects of inhibition agents showed the endocytosis pathway of QD-(AS-ODN+GE11+c(RGDfK)) probe was mainly clathrin-mediated. Western blot confirmed that QD-(AS-ODN+GE11+c(RGDfK)) could further enhance gene silencing efficiency compared to QD-(AS-ODN+GE11) and QD-(AS-ODN+c(RGDfK)), suggesting this dual receptor–targeted gene carrier achieved desired transfection efficiency. In this gene delivery system, QDs could not only be used as a gene vehicle but also as fluorescence probe, allowing for localization and tracking during the delivery process. This transport model is very well referenced for non-viral gene carriers to enhance the targeting ability and transfection efficiency. [ABSTRACT FROM AUTHOR]

Abscess wound caused by bacterial infection is usually difficult to heal, thus greatly affect people's quality of life. In this study, a biodegradable drug-loaded microneedle patch (MN) is designed for targeted eradication of S. aureus infection and repair of abscess wound. Firstly, the bacterial responsive composite nanoparticle (Ce6@GNP-Van) with a size of about 182.6 nm is constructed by loading the photosensitizer Ce6 into gelatin nanoparticle (GNP) and coupling vancomycin (Van), which can specifically target S. aureus and effectively shield the phototoxicity of photosensitizer during delivery. When Ce6@GNP-Van is targeted and enriched in the infected regions, the gelatinase secreted by the bacteria can degrade GNP in situ and release Ce6, which can kill the bacteria by generating ROS under laser irradiation. In vivo experiments show that the microneedle is basically degraded in 10 min after inserting into skin, and the abscess wound is completely healed within 13 d after applying Ce6@GNP-Van-loaded MN patch to the abscess wound of the bacterial infected mice with laser irradiation, which can simultaneously achieve the eradication of biofilm and subsequent wound healing cascade activation, showing excellent synergistic antibacterial effect. In conclusion, this work establishes a synergistic treatment strategy to facilitate the repair of chronic abscess wound. The biodegradable MN patch is loaded with enzyme-responsive antimicrobial nanoparticle Ce6@GNP-Van was developed in this study for eradicating traumatic bacterial infection and promoting stalled healing of abscess wound. The responsive MN system has the following features: (1) the MN patch can physically penetrate and disrupt the bacterial biofilm structure after being applied to the infected site to facilitate the release of the antimicrobial agent; (2) the loading of Ce6 into GNP nanoparticle significantly inhibits the ability of singlet oxygen production and avoids phototoxicity during delivery; (3) Ce6@GNP-Van can target the bacterial community and release the drug only in response to the gelatinase secreted by the bacterial community, and generate a large amount of ROS under laser irradiation, which enhances the specific killing to bacteria by the nanoparticle and thus promotes the wound repairation. The experimental results show that the combination of antimicrobial therapy and MN drug delivery system can meet the requirements of precise targeting of bacteria and stimulation of responsive drug release through rational design, which is expected to achieve wider application in wound healing. [Display omitted] [ABSTRACT FROM AUTHOR]

Schematic diagram of AuPt@g-C 3 N 4 foam fabrication process (a, b, and c), the photos of melamine foam and AuPt@g-C 3 N 4 foam (d); SEM micrographs of AuPt@g-C 3 N 4 foam(e and f) [Display omitted] • AuPt alloy nanoparticles deposited g-C 3 N 4 (AuPt@g-C 3 N 4) foams were successfully fabricated. • AuPt@g-C 3 N 4 foams exhibit enhanced light adsorptions at 550 nm. • AuPt@g-C 3 N 4 foams show the highest photocatalytic activities when the average AuPt alloy nanoparticle size is 21 nm. This work exhibits a remarkable enhancement in visible photocatalytic activity through the fabrication of a 0D/3D composite photocatalyst of AuPt@g-C 3 N 4 foam. Au and Pt elements with a mole ratio of 1:1 are in the bimetallic alloy nanoparticle form, which is uniformly dispersed on the surface of g-C 3 N 4 foam. When the average AuPt alloy nanoparticle size is 21 nm, AuPt@g-C 3 N 4 foam shows the highest photocatalytic activity, which is about 1 time higher than that of bare g-C 3 N 4 foam. Based on the experimental results, the enhanced photocatalytic activity of AuPt@g-C 3 N 4 foam is mainly ascribed to the enhancement of visible-light adsorption and the acceleration of charge separation. [ABSTRACT FROM AUTHOR]

Abstract: (3-aminopropl) triethoxysilaneand modified magnetic nanoparticles with the average diameter of 25.4nm were synthesized in water-phase co-precipitation method. And then these nanoparticles were covalently coupled with alkaline protease as enzyme carrier by using 1,4-phenylene diisothlocyanate as coupling agent. Experiments showed that the immobilized protease can keep the catalytic bioactivity, which can reach to 47.8% when casein was served as substrate. Results showed that the catalytic activity of immobilized protease on these magnetic nanoparticles could retain 98.63±2.37% after 60 days. And it is more stable than the free protease during the shelf-life test. The enzyme reaction conditions such as optimum reaction temperature and pH are the same as free protease. Furthermore, mix-and-separate experiments showed that the immobilized protease could be recycled through the magnetic nanoparticles after the biocatalysis process. When the rapeseed meals were used as substrate, the degree of hydrolysis of immobilized alkaline protease achieved 9.86%, while it was 10.41% for the free protease. The macromolecular proteins of rapeseed meals were hydrolyzed by immobilized protease into small molecules such as polypeptides or amino acids. Thus, a novel efficient and economic way for the recycling of enzymes in the application of continuous production of active peptides was provided based on these magnetic nanoparticles. [Copyright &y& Elsevier]

Abstract: Surface-modified mixed rare earth nanoparticles are prepared and their tribological performances as lubrication additives are evaluated using a four-ball friction and wear tester. The analytical results show that the average size of the particles is less than 30nm and they exhibit excellent anti-wear, load-carrying and good friction-reducing capacities in base stock. Auger electron spectroscopy (AES) and X-ray photoelectron spectrometry (XPS) are performed to investigate their tribochemical mechanism and the results indicate that there is a boundary film composed with ferrous oxides, organic acid, rare earth oxides and complex of rare earth metals formed on the rubbed surface. The high concentration of ferrous oxides in the friction surface, which attributes to the oxidation catalysis of nano rare earth particles during the friction process, may be the main reason that leads to their excellent tribological properties. [Copyright &y& Elsevier]

Abstract: Platinum nanoparticles (PNP) were deposited on the Pt disk electrode by electrochemical deposition, it was found that salicylic acid (SA) had good electrocatalytic oxidation response at the prepared Pt nanoparticles modified Pt disk electrode (PNP/Pt). Then the modified electrode was used to detect SA in weak alkali condition, it was found that the response current was 9.2 times that of bare Pt disk electrode, and the linear range of detection was 2.0×10−5 to 5.0×10−4 M. After that, the electrode was adopted to detect the SA in Zuguangsan, one kind of Chinese medicine, the results showed that the PNP/Pt electrode has low detection limit, high repeatability and stability as SA sensor, could be applied in the detection of SA reliably. [Copyright &y& Elsevier]

Abstract: Salicylic acid (SA) is a biological substance that acts as a phytohormone and plays an important role in signal transduction in plants. It is important to accurately and sensitively detect SA levels. A gold electrode modified with copper nanoparticles was used to assay the electrocatalytic oxidation of salicylic acid. It was found that the electrochemical behavior of salicylic acid was greatly improved at copper nanoparticles, indicating that anodic oxidation could be catalyzed at copper nanoparticles. And the pH had remarkable effect on the electrochemical process, a very well-defined oxidation peak appeared at pH 13.3 (0.2M NaOH). The kinetics parameters of this process were calculated and the heterogeneous electron transfer rate constant (k) was determined to be 1.34×10−3 cms−1, and (1− α)n α was 1.22. The gold electrode modified with copper nanoparticles could detect SA at a higher sensitivity than common electrodes. The electrode was used to detect the SA levels in oilseed rape infected with the fungal pathogen Sclerotinia sclerotiorum. The results showed that the SA concentration reached a maximum during the 10th–25th hours after infection. This result was very similar to that determined by HPLC, indicating that the gold electrodes modified with copper nanoparticles could be used as salicylic acid sensors. [Copyright &y& Elsevier]

Abstract: Au-coated micro-sized polystyrene beads have potential application in suspend chips. A simple approach to prepare well-covered, high-density and stable Au particles-coated micro-sized polystyrene beads (Au@PS) is described in this paper. First, citrate-stabilized and negative charged 20nm Au nanoparticles were synthesized in the experiments, then different charged PS were prepared by grafting, and then the deposition and assembly of Au nanoparticles on the charged PS core were studied. The scanning electron microscope (SEM) images indicate that the electric charge has important influence on the deposition and assembly of Au nanoparticles. The assembly process might be initialized by the aggregation of Au nanoparticles from solution. And the results also indicate that this coating process could be accelerated by the positive electric charge on the PS. This method can be used to prepare well-covered Au@PS composite entities. For the potential application, human IgG as a sample was tested for the ability of protein immobilization. And the Au positive charged Au-coated PS has the protein loading of 16.1μg/g, which is about 6 times of the uncoated beads. [Copyright &y& Elsevier]