LB膜诱导Ba(NO3)2晶体取向生长

In this work, Ba(NO₃)₂ crystals with single crystal face were induced by using the the method of bio-mimetic mineralization and double LB films of behenic acid (BA) as the template. The crystals were characterized by Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD). The crystals were observed in regular square shape with uniform size about 5～8 μm by SEM, and they were found by XRD to grow along the (111) plane. From these experiments, we can conclude that the good selection of the (111) crystal face of Ba(NO₃)₂ is due to the electrostatic interactions , the match between this crystal face and the definite lattice structure of the LB films.     

Determination of fluoride in complex liquid matrices by electrothermal atomic absorption spectrometry with in-furnace oxygen-assisted ashing

A new chemical method is reported for the determination of total fluoride in complex liquids and suspensions, such as fruit juices, urine, serum and blood. It is based on the formation of the A1F radical in a graphite furnace afterin situ oxygen-assisted ashing of the untreated sample. The absorbance of this radical is measured at 227.45 nm. The method is relatively easy to use and provides a low detection limit (14 ng/ml) and reasonable reproducibility (5–10%).     

Control of calcium carbonate polymorphism and morphology through biomimetic mineralization by means of nanotechnology

In vitro biomimetic mineralization by means of nanotechnology allows the formation of calcium carbonate polymorphs at low temperatures (<25 degrees C) under a CO(2) atmosphere of 500-1500 ppm. A two-dimensional zinc-ion ordered array (zinc array), which acts as an active-site mimic of carbonic anhydrase, has been prepared by immersing the self-organized monolayer of 3-(2-imidazolin-1-y)propyltriethosilane on mica (ImSi substrate) into aqueous zinc solution. The zinc array mounted on the ImSi substrate catalyzed the conversion from CO(2) to HCO(3) (-), and accelerated the formation of calcium carbonate. In situ X-ray diffraction data of the formed calcium carbonate on the poly(L-aspartate)-coated chitin substrate (pAsp substrate), with calcium ion-recognition sites, demonstrated that the interaction between the zinc array and pAsp substrates formed both vaterite and calcite at low temperature (15 degrees C) and mainly vaterite at 25 degrees C; this interaction also controlled the morphology of calcium carbonate formed on pAsp substrate.     

稀土化合物TbCl3对成骨细胞系MC3T3-E1增殖、分化和矿化功能的影响

在细胞和分子水平上,研究了稀土化合物氯化铽(TbCl₃)对成骨细胞MC3T3-E1增殖、分化及矿化功能的影响。结果表明,细胞水平上,浓度为0.0001、0.001、0.01、0.1、1和10 μmol·L^-1的TbCl₃均促进MC3T3-E1细胞的增殖、分化及其矿化功能,然而,当浓度升至为100和1000 μmol·L^-1时,TbCl₃表现出抑制作用。分子水平上,浓度为0.0001和0.1 μmol·L^-1的TbCl₃明显上调成骨分化相关基因骨形成蛋白2(BMP-2),碱性磷酸酶(ALP),骨涎蛋白(BSP),Ⅰ型胶原蛋白(Col Ⅰ),骨钙素(OCN)和runt 相关转录因子2(Runx2)的表达。浓度为1 000 μmol·L^-1的TbCl₃则抑制上述成骨分化相关基因的表达。浓度为0.000 1、0.1和1 μmol·L^-1的TbCl₃促进成骨分化相关蛋白Runx2,BMP-2和OCN的表达;结果显示,低浓度的TbCl₃促进MC3T3-E1细胞的成骨分化及矿化功能,而高浓度TbCl₃则呈现出抑制作用。TbCl₃通过调控Runx2的表达刺激早期成骨分化相关基因BMP-2、Col Ⅰ和晚期成骨分化相关基因ALP、OCN的表达,从而诱导MC3T3-E1成骨分化。     

仿生制备有机-无机复合微囊固定化葡萄糖氧化酶

将层层自组装技术与仿生矿化技术相结合,由聚苯乙烯磺酸钠、聚二甲基二烯丙基氯化铵和二氧化硅成功制备(聚苯乙烯磺酸钠-聚二甲基二烯丙基氯化铵)₂-二氧化硅复合微囊.采用扫描电子显微镜、红外光谱和热重对微囊的形貌和化学结构进行了表征.以该复合微囊作为理想载体固定化葡萄糖氧化酶.结果表明,固定于复合微囊中的葡萄糖氧化酶的热稳定性、pH稳定性、操作稳定性得到了提高;在最适条件下,复合微囊固定化葡萄糖氧化酶的酶活回收率为72.85%,米氏常数是游离葡萄糖氧化酶的2.21倍.复合微囊在化学/生物催化、药物/基因传递系统和生物传感器应用方面具有一定的潜能.     

Bioinspired Synthesis of Well‐Ordered Layered Organic–Inorganic Nanohybrids: Mimicking the Natural Processing of Nacre by Mineralization of Block Copolymer Templates

The unique mechanical performance of nacre, the pearly internal layer of shells, is highly dependent on its complex morphology. Inspired by the structure of nacre, the fabrication of well‐ordered layered inorganic–organic nanohybrids is presented herein. This biomimetic approach includes the use of a block copolymer template, consisting of hydrophobic poly(vinylidene fluoride) (PVDF) lamellae covered with hydrophilic poly(methacrylic acid) (PMAA), to direct silica (SiO₂) mineralization. The resulting PVDF/PMAA/SiO₂ nanohybrid material resembles biogenic nacre with respect to its well‐ordered and layered nanostructure, alternating organic–inorganic phases, macromolecular template, and mild processing conditions.

     

Effect of agar hydrogel and magnesium ions on the biomimetic mineralization of calcium carbonate

Here, agar hydrogel was selected as diffusion medium and template to control the biomimetic mineralization of calcium carbonate (CaCO₃). Due to three dimensional network structures and abundant functional groups (such as, hydroxyl groups), Ca²⁺ ions were uniformly distributed in the network and electrostatically attracted. The diffusion speed and range of CO₃^2? ions were mediated by the concentration of hydrogel medium. Under the synergistic effect of Mg²⁺ ions, the crystal CaCO₃ was induced by gas phase diffusion method in the hydrogel system. The results showed that the concentrations of Mg²⁺ ions and agar hydrogel had no obvious effect on the calcite phase of CaCO₃, but the morphologies and sizes changed with concentrations of medium and Mg²⁺ ions. Attribute to template effect, the crystallization behavior and growth rate of CaCO₃ crystals were regulated. Since Mg²⁺ ions were easily adsorbed on the surfaces of unit cell, the unique structure of CaCO₃ was precisely controlled. This study provides a useful reference and inspiration for the understandings of the contributions of ion supply rate in bio-mineralization and hydrogel medium in biomimetic mineralization.     

Synthesis and Assembly of Zinc Oxide Microcrystals by a Low-Temperature Dissolution–Reprecipitation Process: Lessons Learned About Twin Formation in Heterogeneous Reactions

Cobalt-doped zinc oxide single crystals with the shape of hexagonal platelets were synthesized by thermohydrolysis of zinc acetate, cobalt acetate, and hexamethylenetetramine (HMTA) in mixtures of ethanol and water. The mineralization proceeds by a low-temperature dissolution–reprecipitation process from the liquid phase by the formation of basic cobalt zinc salts as intermediates. The crystal shape as well as twin formation of the resulting oxide phase can be influenced by careful choice of the solvent mixture and the amount of doping. An understanding of the course of the reaction was achieved by comprehensive employment of analytical techniques (i.e., SEM, XRD, IR) including an in-depth HRTEM study of precipitates from various reaction stages. In addition, EPR as well as UV/Vis spectroscopic measurements provide information about the insertion of the cobalt dopant into the zincite lattice. The Langmuir–Blodgett (LB) technique is shown to be suitable for depositing coatings of the platelets on glass substrates functionalized with polyelectrolyte multilayers and hence is applied for the formation of monolayers containing domains with ordered tessellation. No major differences are found between deposits on substrates with anionic or cationic surface modification. The adherence to the substrates is sufficient to determine the absolute orientation of the deposited polar single crystals by piezoresponse force microscopy (PFM) and Kelvin probe force microscopy (KPFM) studies.     

脂肪酶仿生固定化及性质

将仿生钛化过程用于脂肪酶固定化,研究了该过程中工艺条件对脂肪酶固定化的影响及固定化脂肪酶的性质.结果表明：0.5 mL浓度8 mg/mL精蛋白诱导剂、0.5 mL浓度6 mg/mL脂肪酶与1 mL,0.25 mol/L钛前驱体（Ti-BALDH）在pH 7.5,0.05 mol/L磷酸盐缓冲液为反应介质的条件下,脂肪酶...     

纳米TiO_2薄膜电极光电催化降解染料RhB的研究

利用光电协同作用可增强TiO2光催化氧化的量子效率[1-3].外加偏压[4-6]是电助光催化过程的一个重要特性,通过对TiO2薄膜电极施加偏压可降低光生电子和空穴的复合速率,不仅可以加速有机污染物的降解,而且还能改变某些底物的降解途径[7].