聚邻甲基丙烯酰胺基苯甲酸/纳米ZnO复合物的制备及其荧光性能研究

利用原子转移自由基聚合(ATRP)法对合成的新单体邻甲基丙烯酰胺基苯甲酸(o-MAABA)进行聚合,通过核磁验证得到符合预先设计的、结构明确的聚合物,聚合物分子量为7900;将纳米ZnO引入到该聚合物P(o-MAABA)中,得到聚合物/纳米ZnO粒子复合物.用红外光谱和差热分析方法对聚合物和复合物进行了表征,并采用透射电镜(TEM)观察了复合物粒子的形貌.红外光谱表明纳米ZnO确实被引入到聚合物链中,并且与聚合物中的某些官能团发生了一定的相互作用;差热分析表明P(o-MAABA)/纳米ZnO复合物的热稳定性较原来聚合物P(o-MAABA)有所提高;TEM观察表明复合物粒子基本为球状,表面较为光滑.P(o-MAABA)/纳米ZnO复合物表现出特殊的荧光性能,与聚合物相比荧光光谱发生红移,并且复合物溶解性较好,能成膜,可望在发光材料方面得到应用.     

Study on the Interaction Mechanism of Lysozyme and Bromophenol Blue by Fluorescence Spectroscopy

The interaction of lysozyme with bromophenol blue (BPB) in acetate buffer (pH 6.0) was studied by fluorescence quenching method for the first time. It was found that BPB could conspicuously quench the fluorescence of lysozyme by the static quenching process, possibly due to the binding on the active site near Trp62. The binding parameters including the binding constant and the number of binding site were calculated. The thermodynamic parameters ΔH°, ΔS° and ΔG° at different temperatures were obtained. The formation of lysozyme–BPB complex depended on the cooperation of the hydrophobic and electrostatic forces. And the binding average distance between lysozyme and BPB was determined. The effect of common metal ions on the binding constant of lysozyme–BPB was also examined.     

Study of Interaction of Silver Nanoparticles with Bovine Serum Albumin Using Fluorescence Spectroscopy

The interaction between silver nanoparticles (SNPs) and Bovine Serum Albumin (BSA) was investigated at physiological pH in an aqueous solution using fluorescence spectroscopy. The analysis of fluorescence spectrum and fluorescence intensity indicates that SNPs have a strong ability to quench the intrinsic fluorescence of BSA by both static and dynamic quenching mechanisms. Resonance light scattering (RLS) spectra indicated the formation of a complex between BSA and SNP. The number of binding sites ‘n’ and binding constants ‘K’ were determined at different temperatures based on fluorescence quenching. The thermodynamic parameters namely ∆H^°, ∆G^°, ∆S^° were calculated at different temperatures and the results indicate that hydrophobic forces are predominant in the SNP-BSA complex. Negative ∆G^° values imply that the binding process is spontaneous. Synchronous fluorescence spectra showed a blue shift which is indicative of increasing hydrophobicity.     

荧光光谱法研究亚甲基蓝与蛋白质的结合反应

应用荧光光谱法研究了水溶液中亚甲基蓝与牛血清白蛋白分子间的结合反应 ,讨论了亚甲基蓝对蛋白质内源荧光的猝灭机理 ,测定了结合常数 (KA=3 44× 10 5L·mol-1)和结合位点数 (n =1 0 3)。依据F rster非辐射能量转移 ,理论确定了授体 受体间的结合距离 (r=1 6 7nm)和能量转移效率 ,并用同步荧光技术考察了亚甲基蓝对牛血清白蛋白构象的影响     

Study of Interaction Between Tryptophan,Tyrosine, and Phenylalanine Separately with Silver Nanoparticles by Fluorescence Quenching Method

Using the spectroscopic method, the individual interaction of the three biochemically important amino acids, which are constituents of protein, namely, tryptophan, tyrosine, and phenylalanine with biologically synthesized silver nanoparticles has been investigated. The obtained UV-Vis spectra show the formation of ground-state complexes between tryptophan, tyrosine, and phenylalanine with silver nanoparticles. Silver nanoparticles possess the ability to quench the intrinsic fluorescence of the aforesaid amino acids by a dynamic quenching process. The binding constant, number of binding sites, and corresponding thermodynamic parameters (ΔH, ΔS, and ΔG) based on the interaction system were calculated for 293, 303, and 313 K. In the case of tryptophan and phenylalanine, with increase in temperature, the binding constant K was found to decrease; conversely, it was found to increase with increase in temperature in the case of tyrosine. The thermodynamic results revealed that the binding process was spontaneous; hydrogen bonding and van der Waals interaction were the predominant forces responsible for the complex stabilization in the case of tryptophan and phenylalanine, respectively, whereas in the case of tyrosine, hydrophobic interaction was the sole force conferring stability. Moreover, the Förster non-radiation energy transfer theory has been applied to calculate the average binding distance among the above amino acids and silver nanoparticles. The results show a binding distance of <7 nm, which ensures that energy transfer does occur between the said amino acids and silver nanoparticles.     

Fluorescence Interaction and Determination of Sulfathiazole with Trypsin

The mechanism of interaction of trypsin with the sulfathiazole was studied through using fluorescence quenching and UV-visible absorption spectra at pH 7.4. The Stern-Volmer quenching constants, binding constants, number of binding sites and the corresponding thermodynamic parameters ΔH^o, ΔS^o and ΔG^o were calculated at different temperatures. The effect of common metal ions on the constants was also discussed. The results suggest that sulfathiazole can interact strongly trypsin and that there is the formation of trypsin-sulfathiazole complex and the interaction can be explained on the basis of hydrogen bonds and van der Waals forces. The binding distance (r) between the donor (trypsin) and acceptor (sulfathiazole) was 3.52 nm based on the Förster’s non-radiative energy transfer theory. The detection and quantification limits of sulfathiazole were calculated as 2.52 and 8.40 μM in the presence of trypsin, respectively. The relative standard deviation (RSD) was 4.086 % for determinations (n?=?7) of a sulfathiazole solution with the concentration of 7.54 μM.     

ZnO纳米颗粒中的表面态发射特性研究

研究了不同粒径ZnO纳米颗粒样品(17～300nm)的时间光谱,通过对各粒径样品时间积分光谱的谱带结构进行高斯拟合解迭,发现光子能量位于ZnO谱带低能侧的高斯拟合成份Xc3的荧光中心波长随粒径的减小而红移,同时发光带的寿命也随之缩短.基于ZnO谱带低能侧的高斯拟合峰发光带强烈依赖于ZnO样品粒径的谱带特性,提出了与ZnO禁带内的表面态能级有关,同时研究表明,表面态在尺寸降到一定程度的纳米体系中起着重要的作用.     

蓝光ZnO薄膜的特性研究

采用反应溅射法在n型硅（100）衬底上制备了ZnO薄膜,分别用X射线衍射仪、原子力显微镜和荧光分光光度计对样品的结构、表面形貌和光致发光特性进行了表征。X射线衍射结果表明,实验中制备出了应变小的c轴择优取向的ZnO薄膜;原子力显微镜观察表明,薄膜表面平整,颗粒大小约为50nm,为柱状结构,颗粒垂直于硅衬底表面生长;在室温光致发光（PL）谱中观察到了波长位于434nm处的较窄的强蓝光发射峰,该蓝光峰的半峰全宽约为50meV。对蓝光峰的发光机制进行了讨论,并推断出该蓝光峰来源于电子从Zn填隙缺陷能级向价带顶跃迁。     

Interaction of Alkali Blue 6B with Cetyltrimethylammonium Bromide

The microsurface adsorption–spectral correction (MSASC) technique has been applied to investigate the interaction of alkali blue 6B (AB6B) with cetyltrimethylammonium bromide (CTAB). The aggregation of AB6B on CTAB obeys the Langmuir isothermal adsorption. The aggregate was characterized by MSASC. For the monomer aggregate AB6B₂CTAB formed, its binding constant is calculated to be K = 3.01·10⁵ and its molar absorptivity to be 2.45·10⁶ liters·cm^–1 at = 690 nm. The adsorption has been used to carry out quantitative detection of cationic surfactant in samples.     

血卟啉及金属血卟啉与甲氧卞氨嘧啶相互作用的荧光光谱研究

荧光光谱法研究了甲氧卞氨嘧啶与血卟啉及金属血卟啉的作用情况 ,考察了酸度对甲氧卞氨嘧啶荧光强度的影响。在 p H=11.0的 KH2 PO4- Na2 HPO4缓冲液中 ,甲氧卞氨嘧啶有较强的荧光峰 ,血卟啉及金属血卟啉对甲氧卞氨嘧啶有明显的识别作用 ,结合常数大于 10 5,结合比均为 1∶ 1。金属血卟啉与甲氧卞氨嘧啶的结合常数小于血卟啉与甲氧卞氨嘧啶的结合常数 ,并对识别机理进行了探讨。     

荧光光谱法和分子模拟技术研究考马斯亮蓝G-250与牛血清白蛋白的相互作用

采用多种光谱技术结合圆二色谱技术研究了考马斯亮蓝G-250(CBBG-250)相互作用于牛血清白蛋白(BSA),探究了两者之间的作用机理。荧光光谱结果表明BSA与CBBG-250结合形式是静态猝灭,随CBBG-250浓度增加,其形成常数随温度逐渐减小,结合比为1∶1,根据Stern-Volmer曲线计算焓变值(ΔH)和熵变值(ΔS)分别为-4.38kJ·mol~(-1)和-6.16J·mol~(-1)·K~(-1),均小于零,证明该过程是一个自发过程。傅里叶红外光谱测定结果表明CBBG-250的加入引起BSA结构的变化,随着CBBG-250溶液浓度的增加,BSA中色氨酸微环境极性被改变,在1 600~1 700cm~(-1)(酰胺带Ⅰ)和1 600~1 500cm~(-1)(酰胺带Ⅱ)处的特征吸收带蓝移。其中1 650cm~(-1)移动至1 710cm~(-1),1 544cm~(-1)移动到1 573cm~(-1),显示BSAα-螺旋(1 650~1 658cm~(-1))和β-折叠(1 620~1 640cm~(-1),1 675cm~(-1))结构发生变化,且α-螺旋含量比结合前有所降低。圆二色谱分析结果表明,两者间通过氢键和范德华力为主的作用力使得BSA二级结构发生变化,α-螺旋含量由42.15%下降至1.27%,该结果进一步被分子建模对接技术证明。     

新铜试剂的荧光光谱

研究了新铜试剂在水溶液中的荧光光谱和荧光量子产率,发现在强酸性条件下,其最大激发和发射波长分别为332nm和429nm,探讨了荧光产生的机理,以罗丹明6G为参比,测得新铜试剂的荧光量子产率为15.2%.     

Interaction of Imidacloprid with Hemoglobin by Fluorescence and Circular Dichroism

Imidacloprid belongs to a major new class of insecticides, called neonicotinoids, which are accounting for 11–15% of the total insecticide market. The binding characteristics of insecticide imidacloprid with hemoglobin (Hb) have been studied by employing different spectroscopic techniques. The results proved the formation of complex between imidacloprid and Hb. Hydrophobic interaction and hydrogen bond dominated in the association reaction. Hydrophobic probe 8-anilino-1-naphthalenesulfonic acid (ANS) competitive experiments indicated that the binding of imidacloprid to Hb primarily took place in hydrophobic regions. The distance between Hb donor and acceptor imidacloprid was 4.88 nm as derived from Förster’s theory. Alternations of Hb secondary structure in the presence of imidacloprid were confirmed by synchronous fluorescence, circular dichroism (CD) and three-dimensional fluorescence spectra. This study enriches our understanding of toxic effect of imidacloprid to the physiologically important protein Hb.     

Interaction of methanol with ZnO surfaces at low temperatures

Adsorption and condensation of methanol on polar (0001) faces of zinc oxide were studied by XPS and UPS. The results indicate that adsorbed CH₃OH is partly transformed to a precursor of a methoxy species at temperatures at low as 105 K. Adsorption saturates only at a coverage of about two monolayers. This double layer seems to become oriented by the structural influence of the (0001) face and stabilized by hydrogen bridge bonds. The sticking coefficient is of the order of 10^?2 while the condensation coefficient on top of the oriented double layer is as low as 10^?3. TDS on a polycrystalline ZnO film supports this model. No other species than CH₃OH occurred in desorption.     

N-N′-二-邻羧基苯基草酰胺荧光特性研究及应用

本文首次研究了酸度、温度对对称草酰胺:N-N’-二-邻羧基苯基草酰胺(OBBE)荧光特性的影响。测定了该试剂的荧光量子产率。发现在pH=8.0～9.5的H_3BO_3—NaOH缓冲介质中,硝酸根离子能使OBBE荧光强度定量猝灭。据此建立了同步荧光猝灭法测定硝酸根离子的新体系。OBBE的激发波长为210nm,发射波长为395nm。荧光猝灭值与NO_3~-在0.0028～0.16mg·L~(-1)呈线性关系,方法的检出限为0.0028mg·L~(-1)。实验了多种干扰离子的影响,用于水中硝酸根离子的测定,结果满意。     

稀土与对硝基苯乙酸配合物的合成、表征及荧光性质

本文合成了三种稀土与对硝基苯乙酸 (HL)的二元固体配合物 ,通过元素分析等手段确定了其配合物的组成为ReL3·H2 O(Re=Eu ,Sm ,Tb)。用红外光谱、紫外光谱、荧光光谱对该类配合物的结构与性质进行了表征。红外谱表明配体以—COO- 形式与中心离子配位 ,同时这一点也被自由配体和配合物的UV谱所证实。EuL3·H2 O的强红色荧光分属于Eu3+ 的 5D0 → 7F1 和5D0 → 7F2 跃迁。     

N掺杂ZnO薄膜的荧光特性研究

以N₂为掺杂源,通过改变O₂∶N₂比,利用射频磁控溅射法在玻璃衬底上制备了具有[002]择优取向的N掺杂ZnO薄膜,研究了ZnO薄膜的光致发光谱随着N掺入量的不同而变化的规律.结果表明,薄膜主衍射峰为402 nm处的发光峰;由于N掺杂量的不同,有的薄膜在445 nm和524 nm处也有发光发存在,但随着薄膜N含量的不同,其发光峰强度明显不同,其峰位也发生了相应的红移或者蓝移.当O₂∶N₂为10∶15时,制备的薄膜N掺杂量最大,光学性能最好,此工艺为研究ZnO薄膜的缺陷类型及导电类型提供了重要的研究参考.     

对硝基苯酚与牛血清白蛋白相互作用的荧光光谱研究

在模拟生理条件下应用荧光光谱和紫外-可见吸收光谱技术研究了牛血清白蛋白(BSA)与对硝基苯酚的相互作用.通过修正Stern-Volmer方程求算出在不同温度下(304,307,310K)的淬灭常数为1.186,1.030,0.940×105 L·mol-1,证实了BSA与对硝基苯酚相互结合作用为单一的静态猝灭过程,并且得到对硝基苯酚与BSA相互作用的热力学参数△H0和△S0分别为-28.061kJ·mol-1和-14.331J·mol-1·K-1,推出两者的相互作用以氢键为主.根据非辐射能量转移理论,计算出对硝基苯酚与BSA相互结合时其供体-受体间的结合距离(r=5.94nm)和能量转移效率(E=0.09).     

Fluorescence Study on the Interaction of Bovine Serum Albumin with P-Aminoazobenzene

In this paper, the interaction between p-aminoazobenzene (PAAB) and BSA was investigated mainly by fluorescence quenching spectra, circular dichroism (CD) and three-dimensional fluorescence spectra under simulative physiological conditions. It was proved that the fluorescence quenching of BSA by PAAB was mainly a result of the formation of a PAAB-BSA complex. The modified Stern-Volmer quenching constant K _a and the corresponding thermodynamic parameters ΔH, ΔG and ΔS at different temperatures were calculated. The results indicated that van der Waals interactions and hydrogen bonds were the predominant intermolecular forces in stabilizing the complex. The distance r?=?4.33 nm between the donor (BSA) and acceptor (PAAB) was obtained according to Förster’s non-radioactive energy transfer theory. The synchronous fluorescence, CD and three-dimensional fluorescence spectral results showed that the hydrophobicity of amino acid residues increased and the losing of α-helix content (from 63.57 to 51.83%) in the presence of PAAB. These revealed that the microenvironment and conformation of BSA were changed in the binding reaction.     

SiO2包覆共轭聚合物CN-PPV纳米探针的制备与荧光性质

采用纳米沉淀法制备了半导体聚合物CN-PPV纳米粒子,并用改进的Stber方法对纳米粒子进行包覆,获得了发光稳定的SiO2/CN-PPV纳米粒子。用动态光散射(DLS)及透射电镜(TEM)方法对粒子尺寸进行了表征,结果表明包覆前的CN-PPV纳米粒子平均粒径约为30 nm,包覆获得SiO2/CN-PPV纳米粒子的平均粒径约为60 nm。通过紫外-可见吸收光谱及荧光光谱对包覆前后纳米粒子的发光性质进行了比较,发现共轭聚合物CN-PPV包覆后的发射光谱与包覆前相比发生了小的蓝移,表明共轭聚合物的分子构型可能发生了微小变化。SiO2包覆可以提高聚合物发光分子的光稳定性,并且提供用于生物分子耦联的表面,这类材料有望在生物医学成像中获得应用。