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In this paper, a novel electrochemical sensing platform for the sensitive detection of interleukin 6 (IL-6) was designed and fabricated. A label-free aptasensor was fabricated by modifying the glassy carbon electrode (GCE) using a nanocomposite composed of carboxylated multi-walled carbon nanotubes (cMWCNTs), cobalt hexacyanoferrate (CoHCF) and gold nanoparticles (AuNPs). The nanocomposite improved electron transfer rate and increased intercalation of signaling molecules. Moreover, it also offers desirable capabilities for the immobilization of biomolecules. The cMWCNTs/CoHCF/AuNPs modified electrode showed good electrochemical characteristics and biocompatibility, thus achieving excellent sensor performance. The differential pulse voltammetry (DPV) was used to detect the peak current of CoHCF in the redox process. The peak current is proportional to the concentration of IL-6 on the electrode surface. Under optimal conditions, the proposed aptamer sensor exhibits a linear range from 0.5 pg/mL to 1000 pg/mL and has a low detection limit of 0.17 pg/mL. In addition, the IL-6 aptamer sensor has good selectivity, high stability, and satisfactory reproducibility, showing broad potential in clinical research and diagnostic applications.

A study employs the rapid scan time-resolved Fourier Transform Infrared (FT-IR) spectroscopy to analyze and demonstrate the electron-transfer mechanism in various molecules undergoing electrochemical redox processes. The analysis of the electron transfer of 1,4-benzoquinone and 1,4-bis(2-ferrocenylvinyl)benzene shows that both the compounds show two-electron transfer in the process, though the electron-communication between the two Fc groups are weak.

A facile solvothermal process is used for obtaining a novel sulfur-terminal Zn(II) complex Zn[(S).sub.2]L (L = N-hexyl-3-{2-[4-(2,2':6',2'-terpyridin-4'-yl)phenyl]ethenyl}carbazole). The Zn[(S).sub.2]L complex has shown two-photon excited fluorescence (TPEF), which is useful for two-photon microscopy imaging in living cells.

The monodisperse silver nanoparticles were synthesized by one-step reduction of silver ions in the alkaline subphase beneath vitamin E (VE) Langmuir monolayers and their structure was investigated. The results suggested that excellent quality V[E.sub.q]/silver nanocomposite LB films might be formed on different substrates without significant variation in the nanoparticle density.

The in situ rapid-scan time-resolved IR spectroelectrochemistry (RS-TR-FTIRS) method was utilized to study the structures of hydrogen bond in the redox process of polyaniline for the first time. There are two types of hydrogen bond. The first was formed between the oxygen atom of water molecule and one hydrogen atom of amine cation radical according to the O-H stretching region (3200-2100 cm-1). Another was formed between the oxygen atom of water molecule and two hydrogen atoms of different amine cation radical according to the O-H stretching region (2700-1700 cm-1). It was found that the hydrogen bond strengthen with the increase of the quantity of amine cation radical in the redox process of polyaniline. The ordered hydrogen bond intensity increases as temperature decreases. The results may be important for understanding of chemical and electric structure and full use the chemical and electronic properties of PANI. [ABSTRACT FROM AUTHOR]

The stability and electronic structures of the new sandwich compounds M(CrB6H6)2 (M = Cr, Mn+, Fe2+) are investigated by density functional theory. All the investigated sandwich complexes are in D6d symmetry and all of them are thermodynamically stable according to the large HOMO-LUMO gap, binding energy, vertical ionization potential and vertical electron affinity analyses, as well as Fe(C5H5)2 and Cr(C6H6)2, following the 18-electron principle. The natural bond orbital, detailed molecular orbitals and adaptive natural density partitioning analyses suggest that the spd-π interaction plays an important role in the sandwich compounds. This work challenges the traditional chemical bonding of the inorganic metal compound, investigates first the bonding style of the d atom orbital interacting with the π MO which was formed by p-d atomic orbitals, and indicates that the metal-doped borane ring can also be an ideal type π-electron donor ligand to stabilize the transition metal. [ABSTRACT FROM AUTHOR]

A new series of hybrid dyes, trans-4-(4′-N,N-dialkylaminostyryl)-N-methyl pyridinium [Cd(SCN)3−]n[alkyl = Me(1), Et(2), Pr(3) and n–Bu(4)] have been successfully synthesized from hybrids of inorganic polymers and organic chromophores. The structures of four new hybrid dyes were characterized by single-crystal X-ray diffraction first. The particular features of the hybrid dyes are (1) the inorganic anions form isolated polymeric one-dimensional zig-zag chains of [Cd(SCN)3−]nwith an extended π-conjugation system within the polymeric –[M–S–C≡N]–M… chain and high polarizabilities; and (2) the organic cationic chromophores determine their optical properties. Experimental results revealed that the TPA cross-section values and overall energy conversion efficiencies of hybrid dyes with different alkyl pendant groups have obviously increased from 1to 4, and in particular, have been substantially enhanced compared to their corresponding iodide analogues 1′–4′. Therefore, we speculate that such increases are attributable to arrangements of infinite anionic [Cd(SCN)3−]nchains and synergic effects with chromophore cations. [ABSTRACT FROM AUTHOR]

The design and tests of a low temperature optically reflected absorbance cell for in situ FTIR spectroelectrochemistry is discussed. It works very well in the temperature range from −100 to +25 °C with temperature control precision within ±0.5 °C. The cell is facile cleaning and convenient manipulation. Besides, it can work, successively, for long time with filling the Dewar flask with liquid N2. The electrochemical performance of the cell is characterized in cyclic voltammetry with K4Fe(CN)6 at room temperature and in steady-state voltammetry with ferrocene at low temperature. The low temperature applicability of the cell for in situ FTIR is demonstrated to observe the electrogenerated intermediate of 1,4-bis(2-ferrocenylvinyl)benzene (p-(Fc–CHᆖCH)2BZ). [Copyright &y& Elsevier]

In the present work, Pd–Pt nanoparticle/polyaniline/carbon nanotube (NP/PANI/CNT) composites, synthesized through the uniform distribution of Pd–Pt NPs, whose single size was controlled to 2–4 nm by citric acid, on a PANI/CNT compound, served as the electrode catalysts for effective methanol oxidation. The structural characteristics were identified by x-ray diffraction, x-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy, and revealed that the Pt65Pd35 NP/PANI/CNT composite displayed superior electrocatalytic oxidation performance and vitality in various Pd–Pt NPs. The results indicated that as an excellent anode catalyst the complex would have application prospects for effective methanol oxidation. [ABSTRACT FROM AUTHOR]

A simple method is described for fabricating gold nanopartitle-modified electrode (NP/SAM/gold), on which the density of NPs on the interface can be controlled by altering SH-terminated thiol abundance in the SAM. [ABSTRACT FROM AUTHOR]

Using Zn(NO3)2, H2SeO3 and graphene oxide as precursors, the zinc oxide/selenium/reduced graphene oxide (ZnO/Se/RGO) composite was facilely electrodeposited on the surface of indium tin oxide glass. The conditions for electrochemical synthesis such as electrodeposition potential and electrolyte composition were studied. The morphology and crystallization of the products as-prepared were characterized using scanning electron microscopy (SEM) and x-ray diffractometry (XRD) respectively. The light absorption and conductivity of the products were studied by UV-visible spectroscopy (UV-vis) and electrochemical impedance spectroscopy (EIS). Based on a series of experimental results, the photoelectrical conversion mechanism and effect factors of the products were explored. By means of synergistic action of n-type ZnO, p-type Se and conductive RGO, the ZnO/Se/RGO composite showed excellent photoelectric conversion under visible light irradiation. [ABSTRACT FROM AUTHOR]