磺化竹红菌素对蛋白质荧光猝灭机理的研究

本文详细研究了磺化竹红菌素对多种蛋白质在溶液状态下的荧光猝灭过程。结果表明，磺化竹红菌素对多种蛋白质荧光猝灭服从Ｓｔｅｎ－Ｖｏｌｍｅｒ曲线。实验观察了温度、粘度、ｐＨ值和盐酸胍对荧光猝灭过程的影响。由于磺化竹红菌素是一两性分子，对于不同蛋白具有不同猝灭过程；磺化竹红菌素对蛋白质的荧光猝灭常数Ｋｑ在１０＾１３ｍｏｌ／Ｌ．ｓ＾－１左右，这说明，磺化竹红菌素是一种比其它蛋白质荧光猝灭剂更加有效的荧光猝灭     

锡离子（Ⅳ）与牛血清白蛋白相互作用的研究

应用荧光光谱和紫外可见吸收光谱研究了锡离子（Ⅳ）与牛血清白蛋白间的结合作用,确定了锡离子（Ⅳ）对牛血清白蛋白的荧光猝灭过程的猝灭机理.测定了不同温度下该结合反应的结合常数,结合位点数,热力学参数.依据能量转移理论确定了锡离子（Ⅳ）和白蛋白间的结合距离.采用同步荧光技术考察了锡离子（Ⅳ）对牛血清白蛋白构象的影响,并讨论了锡离子（Ⅳ）与白蛋白的结合模式.实验结果表明猝灭机理是动态猝灭,锡离子（Ⅳ）与BSA以物质的量比1∶1的比例结合形成复合物,结合过程主要是熵驱动,相互作用主要为疏水作用力.     

高分子半透膜中的荧光猝灭动力学

光学传感器是基于气体或液体猝灭剂对高分子半透膜中荧光分子的猝灭作用而构建的．为了表达它们之间的定量关系,本文从光化学反应动力学模型出发,推导出了一个荧光猝灭反应的动力学方程．该方程能够非常准确地拟合荧光猝灭反应的实验数据,并能很好地说明荧光猝灭的机理,是一个简单而又实用的动力学方程.     

汞(Ⅱ)与明胶蛋白质相互作用的荧光光谱研究

利用荧光光谱技术,研究了pH为7.30时Hg2+离子与明胶的相互作用,用不同的公式对实验结果进行对比处理,计算了结合常数(K)和结合位点数(n)。推测了Hg2+离子对明胶荧光的猝灭机制为Hg2+离子浓度较低时主要是动态猝灭,浓度较高时表现为静态猝灭。     

荧光光谱法研究核黄素与牛血清白蛋白的相互作用

荧光光谱法研究了注射用核黄素(Riboflavin,Rf)与牛血清白蛋白(BSA)的相互作用.核黄素对BSA具有荧光猝灭作用,其猝灭方式为静态猝灭;在301和317K下用Stem-Volmer方程和热力学方程等处理实验数据,求出了结合常数KA、结合位点数n及热力学参数ΔG、ΔH和ΔS.核黄素与BSA之间的作用力主要为氢...     

硝酮化合物对9－氰蒽荧光猝灭作用的研究

本工作对硝酮化合物猝灭９－氰蒽荧光的机制进行了研究，发现不同的９－氰蒽／硝酮体系可能经历包括电子转移、能量转移及竞争吸收等不同的猝灭过程。其中α，Ｎ－二苯基硝酮对荧光猝灭遵循电子转移机制，分别形成猝灭剂和敏化剂的离子自由基，但硝酮正离子自由基不能导致环化反应发生，结果还表明：硝酮化合物的四π电子１，３偶极结构在猝灭过程中起主要作用，因此当光环化反应破环１，３偶极结构生成氧氮丙啶时，即失去其原有的猝灭能力，导致已被猝灭的荧光重新回复。     

光谱法研究富马酸酮替芬与BSA的相互作用

在模拟生理条件下,实验用荧光光谱和紫外吸收光谱研究了不同温度下富马酸酮替芬(KTF)与牛血清白蛋白(BSA)的相互作用机理。研究结果表明:KTF对BSA有显著的猝灭作用,形成1∶1的复合物,其猝灭类型为静态猝灭。由实验数据得出猝灭常数KSV、结合常数KA、结合位点n。热力学参数表明是一个自发过程,其作用力类型主要为疏水作用力。同时,利用同步荧光光谱,分析了KTF对BSA构象的影响,结果表明两者相互作用使酪氨酸残基所处的微环境发生改变。     

荧光光谱研究吡虫啉与牛血清白蛋白的相互作用

运用荧光光谱、紫外光谱法研究了农药吡虫啉与牛血清白蛋白(BSA)的相互作用。实验结果表明,农药分子与BSA形成基态复合物导致BSA内源荧光猝灭,猝灭机理主要为静态猝灭和非辐射能量转移。测定了不同温度下该反应的表观结合常数KA、结合位点数n及结合热力学参数,热力学参数的变化表明上述作用过程是自由能降低的自发分子间作用过程,农药分子与BSA之间以氢键和范德华作用力为主;根据F rster能量转移理论,测得供体与受体间结合距离r与能量转移效率E;并用同步荧光技术考察了农药分子对BSA构象的影响。     

L-半胱氨酸与牛血清白蛋白相互作用的荧光光谱分析

运用荧光猝灭光谱、同步荧光光谱探讨了L-半胱氨酸（L-Cys）与牛血清白蛋白（BSA）的相互作用,并计算了猝灭常数、结合常数、结合位点数以及3个热力学参数△H、△G和△S。结果表明,L-Cys使BSA的内源荧光发生猝灭,BSA的发射峰从350nm蓝移到347．5nm,荧光猝灭机制为动态猝灭;L-Cys与BSA之间的作用力主要为疏水作用力;L-Cys对BSA结构的微环境有一定的影响。     

白屈菜红碱与腺嘌呤核苷、胞嘧啶核苷相互作用的光谱对比研究

通过紫外分光光度计与荧光分光光度计测量表明白屈菜红碱与腺嘌呤核苷、胞嘧啶核苷相互作用后,紫外光谱发生了减色和红移现象,荧光光谱发生了猝灭现象。通过荧光数据定量计算出了白屈菜红碱与腺嘌呤核苷、胞嘧啶核苷的猝灭为静态猝灭,线性拟合方法适用于静态猝灭,因此计算出了白屈菜红碱与腺嘌呤核苷、胞嘧啶核苷的猝灭常数、结合常数和热力学常数。白屈菜红碱-核苷的猝灭常数KSV的大小关系:腺嘌呤核苷>胞嘧啶核苷。白屈菜红碱-核苷的结合常数K的大小关系:腺嘌呤核苷>胞嘧啶核苷。结合比n值:腺嘌呤核苷>胞嘧啶核苷。白屈菜红碱与腺嘌呤核苷的结合反应为吸热反应,而白屈菜红碱与胞嘧啶核苷的结合反应为放热反应,两个反应均为熵驱动的反应。     

Fluorescence quenching of poly(methylphenylsilane) in solution

The solution, electron-transfer fluorescence quenching of a typical aromatic polysilane[poly(methylphenylsilane)] by a series of electronic deficient aromatic monomers is described. The rate of fluorescence quenching is a function of the reduction potential of the quencher, and only very fast processes can be observed, due to the short polymer fluorescence lifetime. The measurement of quenching rate constants, which are considerably larger than diffusion control, suggests that extensive energy migration occurs in the polymer. Although the fluorescence quenching at low quencher concentrations follows Stern-Volmer kinetics, at high concentrations, contributions from static quenching are apparent. Strong fluorescence quenching can either accelerate or inhibit photodegradation, depending on the structure of the quencher.     

Energy transfer and trap site formation in a photopolymer film containing carboxyl groups and benzylidene ketone dyes

The photophysics of the hydrogen-bonded (HB) state and the protonated (PR) state of a photosensitizer, 2,6-bis(4′-diethylaminobenzylidene)cyclopentanone (DBC) in a polymer matrix containing carboxyl groups was investigated by fluorescence spectroscopy and decay curve analysis. The fluorescence spectrum of the excited DBC HB with the carboxyl unit was composed of emission from two species peaking at 567 and 627 nm, which were assigned to the emission from the weakly HB state (HB1) and the strongly HB state (HB2) of DBC, respectively. The excitation energy is able to migrate through the HB1 states and then transfers to the HB2 site and the PR DBC site. At low DBC concentrations, not only PR but also HB2 acts as a deep trap of the excitation energy. The concentration of PR was estimated to be ca. 40% of DBC by the fluorescence decay analysis based on the Förster kinetics. These results indicate that the photoinitiation reaction of this photopolymer system proceeds in competition with the energy transfer to these large amounts of trap sites formed by interaction between the DBC dye and the carboxyl unit of the matrix polymer.     

离子型表面活性剂与牛血清白蛋白作用的比较研究

采用荧光光谱、紫外吸收光谱、动态光散射和Zeta电位法对比研究了十二烷基硫酸钠(SDS)和十二烷基三甲基溴化铵(DTAB)与牛血清白蛋白(BSA)的相互作用机理。结果表明：SDS和DTAB均能猝灭BSA内源荧光,298 K时的猝灭常数Ksv分别为2.64×104和304.21 L/mol。同步荧光光谱和三维荧光光谱显示SDS和DTAB对BSA的构象产生了影响。SDS对BSA荧光猝灭机理为动静联合猝灭机制;热力学计算表明,SDS与BSA的结合过程中,静电力起主导作用,并且能与BSA形成SDS/BSA超分子复合物;DTAB对BSA荧光猝灭机理为动态猝灭,作用力主要是疏水作用。SDS和DTAB与BSA的平均结合距离分别为2.77和4.73 nm。综合结合常数、粒径和Zeta电位等变化,在相同条件下具有较大电荷密度和较小体积极性头基的SDS与BSA具有更强的结合作用。     

Fluorescence Quenching of Alpha-Fetoprotein by Gold Nanoparticles: Effect of Dielectric Shell on Non-Radiative Decay

Fluorescence quenching spectrometry was applied to study the interactions between gold colloidal nanoparticles and alpha-fetoprotein (AFP). Experimental results show that the gold nanoparticles can quench the fluorescence emission of adsorbed AFP effectively. Furthermore, the intensity of fluorescence emission peak decreases monotonously with the increasing gold nanoparticles content. A mechanism based on surface plasmon resonance–induced non-radiative decay was investigated to illuminate the effect of a dielectric shell on the fluorescence quenching ability of gold nanoparticles. The calculation results show that the increasing dielectric shell thickness may improve the monochromaticity of fluorescence quenching. However, high energy transfer efficiency can be obtained within a wide wavelength band by coating a thinner dielectric shell.     

以吖啶染料荧光猝灭为基础的卤素阴离子检测研究

合成了两种吖啶及吖啶橙盐类小分子化合物和带有吖啶盐的三元共聚物，研究了它们在溶液中的荧光被卤素离子猝来的问题，发现它们能强烈地被碘离子所猝灭而不易被氯离子猝灭，表明这类化合物有可能用于在有氯离子存在条件下对碘、溴离子的检测，对荧光猝灭机理进行的研究发现，卤素离子的猝灭能力并不和它们对发光化合物的系间窜越和三重态的生成等有关，而是和阴离子对极化分子的作用减弱了分子内的电荷转移能力相关。     

竹红菌乙素在Triton X-100胶束中的光谱性质及增溶效应研究

为了测定竹红菌乙素(HB)在Triton X-100(TX-100)胶束中的光谱性质及增溶情况,采用紫外-可见分光光度计和荧光分光光度计得到HB在该体系下的吸收光谱和荧光发射光谱,通过HB荧光强度的变化得到增溶情况。在TX-100胶束体系中,竹红菌乙素吸收峰的位置稍有红移且峰型变宽,且荧光发射峰的峰型和峰位均没有大的变化,但最大发射峰强度明显降低。在TX-100胶束的临界胶束浓度(CMC)为58.5μmol·L-1时,HB的最大增溶浓度为50μmol·L-1,得到HB在低浓度TX-100胶束体系中的增溶曲线。该测定方法能够为简单生物模型体系提供一些基础参考数据。     

Löschung der Fluoreszenz aromatischer Urethane durch Ketone

Fluorescence Quenching of N-Arylurethanes by Ketones Fluorescence and photo-Fries reaction of N-aryl-urethanes can be quenched by diffusion-controlled energy transfer to biacetyl, acetone and other aliphatic ketones. Quenching of the photo reaction and fluorescence obeys the Stern- Volmer Equation. The efficiency of quenching may by influenced by solvents and substituents changing the S₁ energies of donors and acceptors. The identical rate constants determined by independent methods demonstrate that quenching of urethane fluorescence and photoreaction by aliphatic ketones occurs completely by singlet energy transfer.     

1．33 dtex细旦有光涤纶短纤维生产工艺

在聚酯熔体中,加入质量分数为0．15%的有光添加剂HB生产1．33 dtex细旦有光涤纶短纤维,探讨了其纺丝及后加工工艺对产品质量的影响。结果表明:纺丝温度284～286℃,纺丝速度950～1 000 m/ min,环吹风温度23～25℃,环吹风压力差250～280 Pa,采用高温紧张热定型,设计合适的喷丝板,优化纺丝、冷却、拉伸工艺,可生产出高质量的高速涤纶缝纫线原料。     

Role of molecular interactions and structural defects in the efficient fluorescence quenching by carbon nanotubes

Fluorescence quenching effect of single walled carbon nanotubes (SWCNTs) and multiwalled carbon nanotubes (MWCNTs) on three most common fluorophores fluorescein, rhodamine 6G and quinine sulphate has been studied and compared. Comparative studies of quenching efficiency shows that SWCNTs are more efficient fluorescence quencher than the MWCNTs. Nature of Stern–Volmer plot was found to be highly non-linear indicating combined effect of dynamic and static quenching. The contribution of dynamic quenching component was assessed through the fluorescence lifetime measurements. Studies on vacuum annealed SWCNTs with low defect contents suggest that structural defects primarily contribute to the large quenching. Fluorescence quenching was found to be dominant even in the cases where adsorption was low implying that surface adsorption play a minor role in the quenching, except for rhodamine 6G. Adsorption isotherms have been studied using Langmuir and Freundlich models. Freundlich model was found to be closer in behaviour implying a multilayer adsorption of molecules on the surface. The contributions of metal nanoparticles and carbon impurities present in different allotropic forms to the fluorescence quenching were also assessed. We speculate that defect mediated nonradiative energy transfer through dipole–dipole coupling may be the dominant mechanism of high efficiency quenching by SWCNTs.     

聚集诱导发光分子TPE-2SO3Na＋与九种蛋白相互作用初探

四苯基乙烯（TPE）衍生物TPE-2SO3Na＋是一种水溶性的聚集诱导发光分子。研究了pH值对TPE-2SO3Na＋荧光强度的影响、TPE-2SO3Na＋对不同蛋白的荧光响应、MP/PNP对TPE-2SO3Na＋荧光的猝灭效应以及MP存在下TPE-2SO3Na＋对不同类型蛋白的荧光响应。结果表明,TPE-2SO3Na＋的荧光强度随着pH值的增大而减弱;在pH值8.0下,TPE-2SO3Na＋对不同类型蛋白的荧光响应不同,MPH、BSA、Pap使TPE-2SO3Na＋荧光强度增强,增强顺序为：BSA〉MPH〉Pap,且蛋白浓度越大,TPE-2SO3Na＋荧光增强效果越明显;MP和PNP都会对TPE-2SO3Na＋产生荧光猝灭,并且PNP的猝灭效率是MP的6倍。用MP猝灭TPE-2SO3Na＋检测蛋白后发现BSA、Pap、Hb有荧光响应,通过加入MP能够使TPE-2SO3Na＋特异性识别BSA,为今后进一步的荧光探针筛选鉴别蛋白方法的建立奠定了基础。