Peapod‐Type Nanocomposites through the In Situ Growth of Gold Nanoparticles within Preformed Hexaniobate Nanoscrolls

A facile in situ method to grow Au nanoparticles (NPs) in hexaniobate nanoscrolls is applied to the formation of plasmonic Au@hexaniobate and bifunctional plasmonic‐magnetic Au‐Fe₃O₄@hexaniobate nanopeapods (NPPs). Utilizing a solvothermal treatment, rigid multiwalled hexaniobate nanoscrolls and partially filled Fe₃O₄@hexaniobate NPPs were first fabricated. These nanostructures were then used as templates for the controlled in situ growth of Au NPs. The resulting peapod structures exhibited high filling fractions and long‐range uniformity. Optical measurements showed a progressive red shift in plasmonic behavior between Au NPs, Au NPPs, and Au‐Fe₃O₄ NPPs; magnetic studies found that the addition of gold in the Fe₃O₄@hexaniobate NPPs reduced interparticle coupling effects. The development of this approach allows for the routine bulk preparation of noble‐metal‐containing bifunctional nanopeapod materials.     

Selective and Sensitive Nitrite Sensor Based on Glassy Carbon Electrode Modified by Silver Nanochains

Herein, we report a facile method for the synthesis of silver nanochains (Ag nanochains) using pyridine as growth directing agent and citrate ions as capping agents in alkaline medium. The characterization of the synthesized high aspect ratio Ag nanochains was accomplished with the help of Transmission Electron Microscopy (TEM) and High Resolution Transmission Electron Microscopy (HRTEM) which demonstrates the thickness below 100 nm. Crystalline nature of the synthesized Ag nanochains was investigated using X‐ray diffractrometry. A sensitive electrochemical nitrite sensor was assembled using synthesized Ag nanochains as electrode modifier. An improved cyclic voltammetric response for the oxidation of nitrite ions was witnessed at the modified GCE surface in comparison to bare GCE in Britton Robinson (BR) buffer (pH 4). The influence of pH on the oxidation peak current of nitrite ions was also examined using cyclic voltammetry. The electrocatalytic oxidation currents attained through amperometric measurements at Ag nanochains modified GCE were linearly dependent on the concentration of nitrite ions in the two ranges of 0.5–7.5 µM, 5–480 µM. Linear calibration plots of Ip vs. concentration of nitrite were also constructed at the proposed sensor using square wave voltammetry and differential pulse voltammetry. The proposed sensing strategy was successfully employed for the determination of nitrite in water samples with excellent recoveries.     

磁场诱导沉淀聚合制备一维Fe3O4/P（MAA-DVB）纳米链

采用溶剂热法制备了单分散Fe3O4纳米粒子,以甲基丙烯酸（MAA）和二乙烯基苯（DVB）为聚合单体,在沉淀聚合过程中通过磁场诱导自组装制备了一维高磁响应性永久连接的Fe3O4/P（MAA-DVB）纳米链.采用扫描电镜（SEM）,透射电镜（TEM）,X射线衍射仪（XRD）,热重分析（TGA）及振动样品磁强计（VSM）等对其形貌、磁含量和磁响应性等进行了分析表征.结果表明,该法制备的一维Fe3O4/P（MAA-DVB）纳米链的磁含量为91%时,其比饱和磁化强度为72emu/g.在外磁场存在条件下,一维Fe3O4/P（MAA-DVB）纳米链将按外界磁场的方向取向.此外,每个豆荚内的Fe3O4纳米粒子规则的排列在一条线上,并通过P（MAA-DVB）聚合物使其均匀分布.     

A glucose biosensor based on chitosan-Prussian blue-multiwall carbon nanotubes-hollow PtCo nanochains formed by one-step electrodeposition

In this paper, a simple one-step electrodeposition method is described to fabricate chitosan-Prussian blue-multiwall carbon nanotubes-hollow PtCo nanochains (CS-PB-MWNTs-H-PtCo) film onto the gold electrode surface, then glucose oxidase (GOD) and Nafion were modified onto the film subsequently to fabricate a glucose biosensor. The morphologies and electrochemistry of the composite were investigated by using Fourier transform infrared (FTIR) spectrometry, scanning electron microscopy (SEM) and electrochemical techniques including cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), respectively. The performances of the biosensor have been investigated by chronoamperometry method under the optimized conditions. This biosensor showed a linear response to glucose range from 1.5 μM to 1.12 mM with a detection limit of 0.47 μM (S/N=3), a high sensitivity of 23.4 μA mM(-1) cm(-2), and a fast response time. The apparent Michaelis-Menten constant (K(M)(app)) was 1.89 mM. In addition, the biosensor also exhibited strong anti-interference ability, excellent stability and good reproducibility.     

Electrochemical Biosensor for Organophosphate Pesticides and Huperzine‐A Detection Based on Pd Wormlike Nanochains/Graphitic Carbon Nitride Nanocomposites and Acetylcholinesterase

A new electrochemical biosensor was developed for organophosphorus pesticides (OPs) and huperzine‐A (hupA) detection based on Pd wormlike nanochains/graphitic carbon nitride (Pd WLNCs/g‐C₃N₄) nanocomposites and acetylcholinesterase (AChE). The morphologies and components of the nanocomposites were analyzed by transmission electron microscopy (TEM) and X‐ray photoelectron spectroscopy (XPS). The Pd WLNCs/g‐C₃N₄ nanocomposites could effectively immobilize enzymes and promote the signal amplification. Under the optimum condition, the proposed biosensor displayed well performance. The linear response ranges for the determination of OPs and hupA were 1.00 nM to 14.96 µM and 3.89 nM to 20.80 µM, respectively. The corresponding detection limits were 0.33 nM and 1.30 nM (S/N=3). Meanwhile, the biosensor owned good reproducibility and stability, and could also be applied to analyze practical samples, which would be a new hopeful method for pesticide analysis.     

Glucometer-based Ultra-sensitive BRAF V600E Mutation Detection Facilitated by Magnetic Nanochains and a Self-made Point-of-Care (POC) Device

We realized the user-friendly and field-based point-of-care detection on a self-made portable device with the aid of personal glucose meter (PGM) for single nucleotide polymorphisms (SNPs) of melanoma and colon cancer marker BRAF V600E with good sensitivity and selectivity by integrating the loop-mediated isothermal amplification (LAMP) reaction and the strand exchange signal transduction. The device is equipped with a rotating magnetic field as well as a heating element, under which the pre-added magnetic nanochains (MNCs) help to homogenize the reaction mixture and overcome the low diffusion efficacy of the reactant and the required temperature for different reactions can be met.     

Herrn Professor Dr. Dr. h. c. mult. J. F. K. Huber

Ohne Zusammenfassung     

Gaspolarographie. II. Mitt.

Zusammenfassung Stickstoffdioxid, Stickstoffmonoxid, Distickstofftrioxid und Distickstoffmonoxid sind in wasserfreiem Dimethylsulfoxid polarographisch erfaßbar.

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Summary Nitrogen dioxide, nitrogen, monoxide, nitrogen trioxide, and nitrous oxide can be detected polarographically in anhydrous dimethylsulfoxide.

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Résumé On peut déceler le peroxyde d'azote, l'oxyde azotique, l'anhydride azoteux et l'oxyde azoteux par polarographie dans le diméthylsulfoxyde anhydre.

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Herrn Prof. Dr.A. A. Benedetti-Pichler zum 70. Geburtstag gewidmet.

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Für die Unterstiitzung der Untersuehungen wird der Regierung der USA gedankt.     

Ein Teleskop-Brenner. D.R.G.M.

Ohne Zusammenfassung     

Le Groupe de Recherche du C.R.N.S. Application des Reactions Nucleaires a l'Analyse Chimique G.A.R.N.A.C.

In this article the research topics dealt with at Research Group for Applications of Nuclear Reactions to Chemical Analysis (GARNAC) are described. Particular emphasis is laid on the main contribution of the GARNAC to the development and the evolution of charged particle activation analysis, evolving with the analytical studies performed and with the scientific and technical progress realized in material and semiconductors science.