牛血清白蛋白与荧光增白剂相互作用的荧光光谱法研究

应用荧光光谱法研究了牛血清蛋白与荧光增白剂CBS-X、BBU、VBL的相互作用.通过Stern-Volmer方程、Lineweaver-BurK方程和双对数曲线进行计算,研究了FWA对BSA内源荧光的猝灭机制.FWA对BSA内源荧光的猝灭主要为静态猝灭和荧光共振能量转移猝灭.测定了荧光增白剂CBS-X、BBU、VBL对BSA的猝灭常量和扩散常量(283 K),确定了荧光增白剂与BSA结合位点数均为1.根据Frster非辐射能量转移理论,计算了BSA与荧光增白剂分子间的结合距离和能量转移效率.通过测定283 K和298 K时供体与受体分子间结合常量,计算了BSA与荧光增白剂作用的热力学参量.BSA与FWA作用的ΔH<0,ΔS>0,并以此确定了BSA 与荧光增白剂分子主要通过静电力进行作用.     

水性丙烯酸聚氨酯涂料中反应性缓蚀剂掺入及其耐蚀性能

利用磷酸和双酚A环氧树脂反应得到功能性缓蚀剂羟基环氧磷酸酯(HEP). 将其添加到水性羟基丙烯酸树脂中,再与水性异氰酸酯固化剂交联,制备了水性羟基环氧磷酸酯/丙烯酸聚氨酯复合涂层(HEP-APU). 由于磷酸酯基团可以与金属基体发生反应,在金属表面形成一层磷化膜,极大的提升了金属的抗闪蚀能力. 利用电化学阻抗谱和极化曲线研究HEP-APU复合涂层对Q235碳钢在3.5wt% NaCl溶液中耐蚀性能. 结果表明,HEP-APU涂料对Q235碳钢具有优越的钝化和耐腐性能,且当HEP在水性丙烯酸聚氨酯涂料中质量分数为0.5%时,所得到的复合涂层的防腐性能最佳.     

Synthesis and Characterization of a Novel Self-colored Fluorescent Polycarbonate Urethane based on the 1,8-Naphthalimide Group

Abstract

The synthesis of a novel self-colored polyurethane (PU) is described using 4-amino-N-propanoic acid-1,8-naphthalimide dye. To synthesize the self- colored PU, the dye was added to the PU prepolymer at the chain extension step. PU and self-colored PU were characterized by using Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy and Fluorometry. The thermal behavior of the PU and self-colored PU were investigated by differential scanning calorimetry (DSC). The spectra indicated that the addition of dye to the polymer chain did not affect the glass transition temperature (T_g?=?-39?°C). Tensile strengths and Young’s modulus of the samples were assessed using a tensile strength test; they revealed that addition of the dye to the polymer structure enhanced the Young’s modulus and increased the mechanical strength of the PU. X-ray diffraction (XRD) was used for evaluation of the crystal phase of the polymer; it revealed that both components were amorphous.     

新型高分子蓝色荧光材料的制备及性能

以吡唑啉为发光功能基团,设计并合成了4种新的聚酰胺类高分子化合物,采用核磁共振氢谱(H 1NMR)和凝胶色谱(GPC)对其结构进行了确证。进而测定了高分子化合物的液体及固体荧光激发、发射光谱,高分子J1,J2和J3具有良好的液体及固体荧光发光能力。所制备的高分子材料具有良好的成膜能力、成本低廉、热稳定性好,有望在电致发光器件中广泛应用。     

Studies of Benzothiazole and Benzoselenazole Squaraines as Fluorescent Probes for Albumins Detection

Series of squaraine benzothiazole and benzoselenazole dyes were studied as possible fluorescent probes for the detection of proteins, particularly albumins. It was shown that majority of the studied squaraines give significant fluorescent response on the human serum albumin (HSA) and bovine serum albumin presence. For squaraine dyes with N-hexyl pendent groups (P-1, P-2, P-3, P-5) about 100−540-fold fluorescence intensity increase upon albumins addition was observed. At the same time in presence of other proteins, namely insulin, avidin from hen egg white, immunoglobulin G (IgG), carbonic anhydrase fluorescence enhancement values were considerably lower —up to 43 times in IgG presence. It was noted that generally, squaraines with long N-hexyl pendent groups demonstrate higher emission increase values upon proteins addition comparing with their analogues with short N-ethyl tails. It was shown that fluorescence intensity enhancement for benzothiazole squaraine dye P-3, relates linearly to the HSA concentration over the wide range—from 0.2 to 500 μg/ml. Together with noticeable selectivity of this dye to albumins, existence of wide dynamic range gives possibility to propose P-3 dye as probe for HSA quantification.     

Photo-physical properties and quantum yield of some laser dyes in new polymer host

The field of laser dyes-active solid polymer materials is a promising field and quite competitive with liquid dye lasers. This paper investigates some photo-physical parameters of pyromethene (PM-567, PM-597) and Rhodamine B dyes incorporated into glycidyl methacrylate (GMA) promising polymeric host matrix. These parameters are: absorption and emission cross-sections, fluorescence lifetime and quantum yield, in addition to FT-Raman spectra as an indication for binding the dye molecules with the backbones of GMA polymeric chain.     

Photophysical Characterization of New 3-Amino and 3-Acetamido BODIPY Dyes with Solvent Sensitive Properties

The structural, electronic and photophysical properties of three new asymmetric, highly fluorescent difluoroborondipyrromethene (BODIPY) dyes, bearing an amino or an acetamido group at position 3 of the chromophoric core, have been studied in different apolar, polar and polar/protic solvents. The presence of the 3-amido group extents the delocalization of the π-system, leading to bathochromic shifts in the absorption and fluorescence bands, as predicted by quantum mechanic calculations. The 3-amino dye shows photophysical properties highly dependent on the solvent polarity and acidity, and is characterized by a hypsochromic shift of its absorption band, with regard to the corresponding acetylated dye, as well as a low fluorescence quantum yield in acid media with proton concentration lower than 4 × 10⁻⁴ M. In media with higher proton concentration, the BF₂ bridge group of the 3-amino dye is removed, yielding the corresponding non-fluorescent dipyrromethene precursor. These results suggest that the 3-amino dye could be used as a fluorescence probe for the study of the acidity of different environments.     

Fluorescence lifetime measurements to determine the core-shell nanostructure of FITC-doped silica nanoparticles: An optical approach to evaluate nanoparticle photostability

In this paper, we described a novel fluorescence lifetime-based approach to determine the core-shell nanostructure of FITC-(fluorescein isothiocyanate, isomer I) doped fluorescent silica nanoparticles (FSNPs). Because of phase homogeneity between the core and the shell, electron microscopic technique could not be used to characterize such core-shell nanostructure. Our optical approach not only revealed the core-shell nanostructure of FSNPs but also evaluated photobleaching of FSNPs both in the solvated and non-solvated (dry) states. The FSNPs were produced via Stöber's method by hydrolysis and co-condensation reaction of tetraethylorthosilicate (TEOS) and fluorescein linked (3-aminopropyl)triethoxysilane (FITC-APTS conjugate) in the presence of ammonium hydroxide catalyst. To obtain a pure silica surface coating, FSNPs were then post-coated with TEOS. The average particle size was 135 nm as determined by TEM (transmission electron microscope) measurements. Fluorescence excitation and emission spectral data demonstrated successful doping of FITC dye molecules in FSNPs. Fluorescence lifetime data revealed that approximately 62% of dye molecules remained in the solvated silica shell, while 38% of dye molecules remained in the non-solvated (dry) silica core. Photobleaching experiments of FSNPs were conducted both in DI water (solution state) and in air (dry state). Severe photobleaching of FSNPs was observed in air. However, FSNPs were moderately photostable in the solution state. Photostability of FSNPs in both solution and dry states was explained on the basis of fluorescence lifetime data.     

Oxygen Barrier Properties of Waterborne Polyurethane/Silica Hybrids

The oxygen barrier properties of films obtained from waterborne polyurethane/silica hybrid dispersions were analyzed. Two different types of polyurethanes were used, based on poly(propylene glycol) and poly(1,4-butylene adipate). Three different strategies were followed in the preparation of the hybrid dispersions. In the first type of materials (series 1), the inorganic part came exclusively from the covalent incorporation of trifunctional silane groups into the polymeric chains. The other two series contained, in addition to the trifunctional silane groups, tetrafunctional silane groups either physically blended (series 2) or “in situ” generated (series 3). Materials of series 1 showed an increase of the oxygen permeability coefficient with the silane content. However, the other two types of materials presented just the opposite dependence. In this latter case, the systems containing “in situ” generated silica (series 3) presented higher permeability coefficient values, probably because of the steric hindrance imposed by the polyurethane that gave rise to silica networks containing silanol groups and free volume holes. Moreover, lower permeability coefficient values were obtained when larger size particles were added. This fact could mean that the polyurethane/silica interface effects were not totally hindered even when the organic/inorganic phases were covalently bonded.     

Synthesis and Characterization of a Fluorescent Water-Borne Polyurethane Based on a Novel Naphthalimide Dye

A waterborne-polyurethane (WPU) dye, based on the fluorescent dye 4-diamino propane-N-allyl-1,8- naphthalimide (WPU-DAN), was synthesized by attaching 4-diamino propane-N-allyl-1,8- naphthalimide (DAN) onto both ends of the polyurethane (PU) chains according to a prepolymer?ionomer process. The synthetic process was confirmed by Fourier transform infrared spectroscopy (FTIR) and UV-visible absorption. The glass transition temperature, molecular weight and average particle sizes were measured. The glass transition temperatures of WPU and WPU-DAN were 46.6 and 49.8°C, respectively. In addition, the particle size distributions of WPU-DAN and WPU were 140 and 134 nm, respectively. The thermal behaviour of WPU-DAN showed improvement compared to WPU. The fluorescence intensity of WPU-DAN was enhanced more than DAN due to the naphthalimide groups attached to the chains, and the fluorescence intensity of WPU-DAN and DAN were increased by increasing temperature. Moreover, the fluorescence intensity of WPU-DAN emulsion was stable during 30 days and no loss of fluorescence intensity occurred for these days.