环丙沙星与三氟甲基丙烯酸分子印迹自组装体系的理论研究

采用量子化学长程校正方法, 以环丙沙星(CIP)为印迹分子, 三氟甲基丙烯酸(TFMAA)为功能单体, 研究了CIP与TFMAA单体分子印迹聚合物(MIPs)自组装体系的构型、 成键作用位点、 反应的结合能、 作用机理及其选择性. 计算结果表明, CIP印迹分子与TFMAA单体通过氢键形成分子结构互补的有序排列复合物, 当印迹分子与功能单体配比(印迹比例)为1: 6时, 其复合物能量最低; 通过模拟洗脱CIP后的复合物对恩诺沙星(ENR)、 诺氟沙星(NOR)、 氧氟沙星(OFL)再结合的结合能可以预测MIPs对CIP印迹分子的选择性, CIP与OFL共存时MIPs对CIP的选择性最好. 采用不同印迹比例, 测定聚合物对CIP的吸附量, 结果表明, 印迹比例为1: 6时, 聚合物吸附量最大, 且对OFL的选择因子最大, 实验结果与计算结果一致.     

A new application of scanning electrochemical microscopy for the label-free interrogation of antibody–antigen interactions: Part 2

Within this paper we describe the use of scanning electrochemical microscopy (SECM) to fabricate a dotted array of biotinylated polyethyleneimine which was then used to immobilise first neutravidin and then a biotinylated antibody towards a relevant antigen of interest (PSA, NTx, ciprofloxacin). These antigens were selected both for their clinical relevance but also since they display a broad range of molecular weights, to determine whether the size of the antigen used effects the sensitivity of this approach. The SECM was then used to image the binding of both complementary and non-complementary antigens in a label-free assay. Imaging of the arrays before and following exposure to various concentrations of antigen in buffer showed clear evidence for specific binding of the complementary antigens to the antibody functionalised dots. Non-specific binding was also quantified by control experiments with other antigens. This demonstrated non-specific binding across the whole of the substrate, thereby confirming that specific binding does occur between the antibody and antigen of interest at the surface of the dots. The binding of ciprofloxacin was investigated both in simple buffer solution and in a more complex media, bovine milk.     

A Fiber Optic Lactate Biosensor with an Oxygen Optrode as the Transducer

Abstract

A biosensor for continuous determination of lactate is presented. Lactate monooxygenase was immobilized covalently on nylon membranes, and the consumption of oxygen was measured by following, via a fiber optic bundle, the changes in the fluorescence of an oxygen-sensitive dye dissolved in 10- and 25-um silicone membranes placed beneath the enzyme layer. Oxygen is consumed as a result of the oxidation of lactate by the enzyme, and the decrease in its partial pressure is indicated by the fluorescent dye. For two types of sensors (with different nylon membranes and different thicknesses of the indicator layer) the analytical ranges were 2–50 mM and 0.3–6.0 mM, with response times (t₉₀) of 2.3–3.0 and 4.0–6.0 min, respectively.     

Studies of the Interaction Between Ciprofloxacin and the Hemocyanin From Chinese Mitten Crab Eriocheir Japonica Sinensis

The interactions between ciprofloxacin and hemocyanin were investigated by ultraviolet-vis absorbance, circular dichroism, and fluorescence spectra techniques. The ciprofloxacin effectively quenched the intrinsic fluorescence of hemocyanin via static quenching. There is only one class of binding site at the interface of hemocyanin. The hydrophobic and electrostatic interactions played a major role in the binding process of ciprofloxacin-hemocyanin system. The distance between the tryptophan residues and ciprofloxacin was calculated using F?rster theory to be 3.859 nm. The alteration of the environment of tryptophan residues and the secondary protein structure in the presence of the ciprofloxacin was confirmed by circular dichroism, synchronous, and three-dimensional fluorescence spectra.     

Hydrothermal syntheses,crystal structures and antibacterial activities of two Cu(II) complexes with quinolones

Hydrothermal reactions of ciprofloxacin with Cu(ClO₄)₂?·?6H₂O, and ofloxacin with Cu(CH₃COO)₂?·?4H₂O, yield two metal complexes: [Cu(H-Cip)₂]?·?(ClO₄)₂?·?6H₂O (1) and [Cu(Ofl)₂?·?H₂O]?·?2H₂O (2), which were characterized by elemental analysis, IR and single crystal diffraction analyses. Compounds 1 and 2 were screened for antibacterial activities against Staphylococcus aureus, Escherichia coli, Candida albicans and pseudomonas aeruginosa.     

Lactate Biosensor Based on the Adsorption of Polyelectrolyte Stabilized Lactate Oxidase into Porous Conductive Carbon

 In this work the development a lactate biosensor is illustrated. Lactate oxidase is stabilized with the cationic polyelectrolyte diethylaminoethyl-dextran, and the resulting enzyme-polyelectrolyte complexes are physically absorbed into a highly porous and conductive carbon electrode for the construction of the biosensor. The amount of diethylaminoethyl-dextran used is optimized with respect to the sensor sensitivity and stability. Optimum results obtained with enzyme solution containing 0.5% w/v diethylaminoethyl-dextran and 200 U/ml lactate oxidase. The resulting biosensors present increased operational (over 240 hours of continuous polarization) and storage stability (more than 5 months), while the reproducibility was calculated to be better than 5.0% RSD.     

LDH参与的机械-光信号转换体系的吸收光谱研究

用紫外-可见分光光度法研究了乳酸脱氢酶(LDH)参与的,以NADH与DPIP.,O₂为主体的机械-光信号振荡转换体系。LDH的酶催化作用使此振荡体系的信号转换效率大大提高,在无乳酸情况下,当DPIP.和NADH的摩尔比为1∶4.5时的平均循环周期由108 min缩短为34 min;在乳酸存在下,此体系的平均循环周期由108 min缩短为29 min。推测LDH的促进作用主要是通过对NADH的活化实现的,其次是通过酶促乳酸脱氢作用补充体系中的NADH获得的。结果说明,酶的催化作用在某些双底物之一存在的反应情况下,也会明显表现出来。     

乳酸亚铁中总铁的溶样及比色测定

本文研究在ＨＮＯ３－ＨＣｌ体系乳酸亚铁中的Ｆｅ＾２＋会被氧化成Ｆｅ＾３＋，用碘基水杨酸比色法就能准确测定总铁量，回收率在９８％－１００％，相对标准偏差为１．１４％，摩尔吸光系数为５．６×１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，含铁量在０－７００μｇ／１００ｍＬ范围内符合比耳定律。     

含磷聚酸酐药物控制释放材料的研究

将二氯磷酸乙酯或苯酯与对羟乙氧基苯甲酸反应，制备了含磷酸酯键的二羧酸，将其转化为混合酸酐并通过熔融缩聚，合成了主链含磷酸酯键的聚酯酐，以含磷酸酯键二羧酸与１，３－双（４－羧基苯氧基）丙烷（ＣＰＰ）熔融共聚，得到一链到酯键的共聚酸酐研究了两类聚酸酐的体外降解，酶促降解，这些聚酸酐的降解过程包含酸酐键的断裂，也包含磷酸酯键断裂，前者比后者更容易断裂，核糖核酸酶和碱性磷酸酶能加速这类聚酸酐的降解，还研究     

二维层状NiO/g-C3N4复合材料在无铁光电类芬顿体系中有效去除环丙沙星的研究

Excessive use of ciprofloxacin (CIP) has proven to be a significant threat to the ecological environment. In this work, a novel Fe-free photo-electro-Fenton system was designed for the degradation of CIP in water. The NiO/g-C₃N₄ composites were synthesized by a simple solvothermal method. The crystalline phases and chemical compositions of the different catalysts were determined via X-ray diffraction (XRD) analysis. Fourier transform infrared (FT-IR) spectroscopy further confirmed the molecular structures of the different composites. The results proved the successful synthesis of NiO/g-C₃N₄ composites. The morphology of the material was obtained using scanning electron microscopy (SEM), which showed that the structure of the optimal NiO/g-C₃N₄-60% was two-dimensional and flower-like. The transmission electron microscopy (TEM) analysis further proved that the NiO/g-C₃N₄-60% possessed a layered structure. Owing to the layered structure, the NiO/g-C₃N₄-60% boasts of a large specific surface area and abundant active sites, which were beneficial for the transmission of electrons and oxidation of CIP. Furthermore, it was evident from the X-ray photoelectron spectroscopy (XPS) analysis that the Ni²⁺ and Ni³⁺ coexisted, and there was low coordination oxygen with defects in the NiO/g-C₃N₄-60% composite. The electron paramagnetic resonance (EPR) spectrum also proved the existence of oxygen vacancies, which not only facilitated the activation of H₂O₂, but also promoted the formation of stable mixed valence states of metal ions. UV-vis diffuse reflection spectrum (UV-Vis DRS), photoluminescence (PL), and electrochemical tests showed that NiO/g-C₃N₄-60% exhibited the strongest light absorption capacity, lowest charge transfer resistance, and fastest charge separation efficiency, which was beneficial for the generation of active species and the rapid degradation of CIP. Therefore, the flower-like NiO/g-C₃N₄-60% composites exhibited photoelectric synergy in the photo-electro-Fenton process. They not only effectively decomposed the H₂O₂ produced in the electro-Fenton process into ·OH by the conversion of Ni³⁺/Ni²⁺, but also generated photogenerated electrons and holes to promote the production of ·OH, ·O₂^–, and h⁺ under light irradiation to improve the degradation efficiency of CIP. When the optimal NiO/g-C₃N₄-60% served as a catalyst in the photo-electro-Fenton system, the degradation efficiency of CIP reached approximately 100% in 90 min and the mineralization efficiency reached 82.0% in 120 min. In addition, compared with the traditional Fenton system (the optimal pH value of which is 2.8–3.5), the novel photo-electro-Fenton system possessed a wider range of pH, with a final CIP degradation efficiency of 78.8% at a pH value of 6. The NiO/g-C₃N₄-60% also demonstrated excellent structural stability in the photo-electro-Fenton system. After five consecutive cycles, the degradation efficiency was maintained at 96.3%. Based on the results of high-performance liquid chromatography-mass spectrometry (HPLC-MS), two possible pathways for CIP degradation were proposed. This study provides a theoretical basis for the rapid degradation of antibiotics in wastewater.