磁性聚苯胺纳米微球的合成与表征

报道了具有核壳结构的Fe3 O4 聚苯胺磁性纳米微球的合成方法和表征结果 .微球同时具有导电性和磁性能 .在优化的实验条件下 ,可得到饱和磁化强度Ms 为 5 5 .4emu/g ,矫顽力Hc 为 6 2Oe的磁性微球 .微球的导电性随着微球中Fe含量的增加而下降 .微球的磁性能则随着Fe含量的增加而增大 .Fe3 O4 磁流体的粒径和磁性聚苯胺微球的粒径均在纳米量级 .纳米Fe3 O4 粒子能够提高复合物的热性能 .实验表明 ,磁流体和聚苯胺之间可能存在着一定的相互作用 ,但这种相互作用较为复杂 ,难于研究 .     

Surface modification of polyacrylonitrile film by anchoring conductive polyaniline and determination of uricase adsorption capacity and activity

Polyacrylonitrile (PAN) films were modified with chemical polymerization of conductive polyaniline (PANI) in the presence of potassium dichromate as an oxidizing agent. The effect of aniline concentration on the grafting efficiency and on the electrical surface resistance of PAN and (PAN/PANI)-1-3 composite film was investigated. The surface resistances of the conductive composite films were found to be between 6.32 and 0.97 kΩ/cm. As the amount of grafted PANI increased on the PAN films, the electrical resistance of composite film decreased. The PAN/PANI composite films were also characterized using SEM and FTIR. The changes in the surface properties of the films were characterized by contact angle measurements. As expected, the PAN, PAN/PANI and PAN/PANI-uricase immobilized films, exhibited different contact angle values and surface free energy due to different interactive functional groups of the films.The conductive films were well characterized and used for immobilization of uricase. The amount of adsorbed enzyme increases with the increase of surface concentration of grafted fibrous polyaniline polymer. The maximum amount of immobilized enzyme onto composite film containing 2.4% PANI was about 216 μg/cm² (i.e., PAN/PANI-3). The immobilized uricase was reused 24 times in batch wise assay in a day. Finally, the immobilized uricase enzyme system was successfully fabricated and applied to determine the uric acid level in human serum samples.     

In situ synthesis and characterization of LiNi0.5La0.08Fe1.92O4-polyaniline core-shell nanocomposites

Core-shell-structured LiNi_0.5La_0.08Fe_1.92O₄-polyaniline (PANI) nanocomposites with magnetic behavior were synthesized by in situ polymerization of aniline in the presence of LiNi_0.5La_0.08Fe_1.92O₄ nanoparticles. The structure, morphology and magnetic properties of samples were characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FTIR), UV-vis absorption, transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) technique. The results of spectroanalysis indicated that there was interaction between PANI chains and ferrite particles. TEM study showed that LiNi_0.5La_0.08Fe_1.92O₄-PANI nanocomposites presented a core-shell structure with a magnetic core of 30-50 nm diameter and an amorphous shell of 10-20 nm thickness. The nanocomposites under applied magnetic field exhibited the hysteresis loops of the ferromagnetic nature. The saturation magnetization and coercivity of nanocomposites decreased with decreasing content of LiNi_0.5La_0.08Fe_1.92O₄. The polymerization mechanism and bonding interaction in the nanocomposites have been discussed.     

Analysis of blood proteins on protein arrays with a spectral surface plasmon resonance biosensor

We investigated whether blood proteins can be analyzed on protein arrays with a spectral surface plasmon resonance (SPR) biosensor. We modified gold arrays with a mixture of mercaptoundecanoic acid and mercaptohexanol, and immobilized blood proteins-hemoglobin (Hb) and haptoglobin (Hp), or their antibodies. We analyzed interactions of Hb with Hp on protein arrays by measuring the shift of resonance wavelength, and a significant interaction was observed when Hp was used as a ligand. Then, we fabricated antibody arrays with antibodies against Hb and Hp, and analyzed binding of blood proteins onto the arrays. Anti-Hb showed a specific interaction with Hb on the antibody arrays. Interaction of anti-Hp with Hp was specific when Hp was used as capture molecules. The shift of resonance wavelength caused by the interaction of blood proteins was explained by changes of refractive index on the gold surfaces of protein arrays. The present work suggests that spectral SPR biosensors can be used as a useful tool for the analysis of blood proteins on protein arrays.     

有机溶剂热生长技术制备纳米CdS及其与聚苯胺复合膜的光学性能

以溶剂热生长技术(solvothermal technique)制备了半导体CdS的纳米微粒,并采用XRD、TEM、ED对其结构进行表征。在ITO导电玻璃上,采用电化学方法合成聚苯胺薄膜,以提拉的方法将CdS的纳米颗粒涂布其上,自组装得纳米CdS／PANI膜,并以荧光光谱(PL)及非线性Z-扫描法研究其光学特性。实验结果显示：经CdS修饰后,CdS／PANI膜的荧光发射峰强度增强,位置较单一PANI膜移至420nm处,同时经修饰后的复合物膜的非线性光学特性也有显著的提高。     

Tuning the phase diagrams: the miscibility studies of multilactate liquid crystalline compounds

Design of binary and multicomponent liquid crystalline mixtures is a very powerful tool to reach the desired self-assembling properties. Beyond many advantages, this method has a distinct negativity – it is very material-consuming. While working with unique chiral materials in the research laboratory, this problem can be solved by applying miscibility study by the contact preparation method. In this work, the miscibility studies of lactic acid derivatives and non-chiral/chiral liquid crystalline molecules of different structure have been done in order to establish the phase diagrams. Special attention is focused on the ferro(antiferro)electric smectic phases.     

Immobilizing a single pybox ligand onto a library of solid supports

Chiral pyridinebis(oxazoline) (pybox) ligands can be efficiently immobilized onto silica through position 4 of the pyridine ring. The crucial intermediate in this strategy is 4-chloropybox, which is prepared in good yield from chelidamic acid. 4-Chloropybox reacts with p-hydroxybenzaldehyde and p-aminophenol to give two intermediates (pybox-CHO and pybox-NH2) that allow to introduce the formyl and amino groups able to link to spacers with triethoxysilyl groups. The modified ligands and their ruthenium complexes are immobilized by grafting onto preformed silicas or, alternatively, the support is created by sol-gel synthesis using the functionalized chiral ligand as a silica monomer. In this way it is possible to create a library where the variation involves the support rather than the catalyst. The aim of this approach is to study the influence of different parameters, such as the textural properties of the support and the immobilization method, on the functionalization and catalytic performance. Some of the immobilized complexes are compared as heterogeneous catalysts in the cyclopropanation reaction of styrene with ethyl diazoacetate.     

Surface modification of hydroxyapatite nanoparticles by poly(l-phenylalanine) via ROP of l-phenylalanine N-carboxyanhydride (Pha-NCA)

The surface of hydroxyapatite nanoparticles was modified by poly(l-phenylalanine) via the ring opening polymerization (ROP) of l-phenylalanine N-carboxyanhydride. The preparation procedure was monitored by Fourier transform infrared spectroscopy (FTIR), and the modified hydroxyapatite was characterized by thermal gravimetric analysis (TGA) and X-ray diffraction (XRD). The results showed that the surface grafting amounts of poly(l-phenylalanine) on HA ranging from 20.26% to 38.92% can be achieved by tuning the reaction condition. The XRD patterns demonstrated that the crystalline structure of the modified hydroxyapatite was nearly the same with that of HA, implying that the ROP was an efficient surface modification method. The MTT assay proved that the biocompatibility of modified HA was very good, which showed the potential application of modified HA in bone tissue engineering.     

Structure/Property Relationships for Poly(Vinylidene Fluoride)/Doped Polyaniline Blends

Poly(vinylidene fluoride) (PVDF) and its blends with polyaniline (PANI) doped with dodecylbenzene sulfonic acid (DBSA) were characterized by electrical conductivity, differential scanning calorimetry (DSC) and X‐ray scattering techniques.

The onset of an infinite cluster (InC) of conducting, highly anisometric PANI/DBSA particles in PVDF/(PANI/DBSA) blends was observed at the percolation threshold as low as w*≈3.5 wt.%. The small angle X‐ray scattering (SAXS) data confirmed the expected spatial organization of PANI/DBSA needles into fractal‐like structures above w*. A slight decrease of both the DSC and the wide‐angle X‐ray scattering (WAXS) degrees of crystallinity of PVDF with the PANI/DBSA mass content w was explained by strong interactions at the PVDF/(PANI/DBSA) interface resulting in the loss of crystallizability of a fraction of sterically immobilized chains of PVDF in boundary layers around PANI/DBSA particles. The available data suggest that the conductive paths within InC of PANI/DBSA in PVDF/(PANI/DBSA) blends were formed primarily by the end‐to‐end contacts of PANI/DBSA fibrils.     

Immobilized protease on the magnetic nanoparticles used for the hydrolysis of rapeseed meals

(3-aminopropl) triethoxysilaneand modified magnetic nanoparticles with the average diameter of 25.4 nm 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.