锌离子与牛血清白蛋白相互作用的研究

用荧光光谱法研究了锌离子(Zn2+)与牛血清白蛋白(BSA)的作用机制.实验表明,Zn2+对BSA具有荧光猝灭作用,其猝灭方式为静态猝灭.求出了猝灭常数、结合常数及结合位点数.利用同步荧光光谱研究了Zn2+对BSA分子荧光光谱的影响.     

番红花红T与牛血清白蛋白作用的光谱特性

用荧光光谱法研究了番红花红T与牛血清白蛋白(BSA)的结合反应.结果显示番红花红T对牛血清白蛋白的荧光有猝灭作用,其猝灭类型属于静态猝灭;得到了不同温度下的结合常数和结合位点数;利用Van't Hoff方程计算得到该猝灭反应的热力学参数,结果表明番红花红T主要以静电作用力与BSA相互作用;同步荧光光谱显示番红花红T对B...     

L-半胱氨酸修饰的金纳米粒子与牛血清白蛋白相互作用的荧光光谱研究

采用荧光猝灭光谱和同步荧光光谱研究了L-半胱氨酸修饰的金纳米粒子(Cys-GNPs)与牛血清白蛋白(BSA)间的相互作用。根据荧光猝灭相关方程计算了Cys-GNPs与BSA相互作用的结合常数和结合位点数,探讨了其荧光猝灭机制为静态猝灭,并且根据热力学参数确定了二者间的作用力类型,推断出Cys-GNPs和BSA间主要靠疏水作用力结合。同步荧光光谱表明,二者的相互作用没有导致牛血清白蛋白的构象及色氨酸残基的微环境发生明显变化。     

顺式氰戊菊酯与牛血清白蛋白相互作用的荧光光谱研究

用荧光光谱法研究了在生理pH值条件下杀虫剂顺式氰戊菊酯与牛血清白蛋白(BSA)的相互作用.结果表明:顺式氰戊菊酯对BSA的荧光有较强的猝灭作用,该猝灭属于静态猝灭.根据猝灭结果求得了不同温度下顺式氰戊菊酯与牛血清白蛋白作用的结合位点数、结合常数及反应热力学参数,并据此推测了它们之间主要的相互作用力为疏水作用力.还用同步荧光光谱法探讨了顺式氰戊菊酯对BSA构象的影响.     

硫酸头孢匹罗与牛血清白蛋白结合反应的发光机理

在人生理条件下,利用荧光猝灭法、同步荧光法及共振光散射法,分别研究了不同温度下硫酸头孢匹罗(CPS)与牛血清白蛋白(BSA)间的结合反应.结果表明:随着CPS浓度的增加,BSA的荧光、共振散射光依次降低,其荧光猝灭为静态猝灭过程并伴随非辐射能量转移作用.反应的结合常数为104数量级.结合位点数约为1;结合位点位于BSA...     

3-羟基-6-[(4-羧基苯基)偶氮]-苯甲酸与牛血清蛋白结合反应的荧光光谱

采用荧光光谱研究3-羟基-6-[(4-羧基苯基)偶氮]-苯甲酸(HCPAB)与牛血清蛋白(BSA)的相互作用.通过测定298K和310K下HCPAB与BSA的荧光猝灭光谱,计算得到荧光猝灭常数、反应的结合常数、结合位点数及热力学参数,得出这种荧光猝灭机理符合静态猝灭;由Foerster能量转移机理,计算了当BSA与HCPAB比例为1∶1时分子间距离r=3.18nm和能量转移效率E=0.23,并由同步荧光光谱显示HCPAB与BSA的结合位点更接近于色氨酸.     

依巴斯汀与牛血清蛋白相互作用的荧光光谱研究

在PH=7.4的PBS缓冲溶液中,利用荧光光谱研究了在依巴斯汀存在下牛血清蛋白的荧光猝灭特征.通过实验得到三个温度(298K,305K,312K)下的猝灭光谱曲线组,根据Stern-Volmer方程计算各相应温度下的猝灭常数发现:依巴斯汀对牛血清蛋白的荧光猝灭机制属于静态猝灭.通过对依巴斯汀-牛血清蛋白体系的热力学参量的计算得出依巴斯汀与牛血清蛋白间的相互作用力类型为疏水作用力.通过拟合双对数方程计算出在以上三个温度下结合常数分别为3.27×104 L·mol-,4.11×104 L·mol-,7.59×104 L·mol-,结合位点数为0.98、1.02、1.08.依据Frster非辐射能量转移理论计算出荧光供能体(牛血清蛋白)与受能体(依巴斯汀)之间的结合距离为2.8nm,利用同步荧光光谱及三维荧光光谱技术分析了依巴斯汀对牛血清蛋白构象的影响.     

柠檬酸钠与牛血清白蛋白的相互作用

用荧光光谱法研究了柠檬酸钠与牛血清白蛋白( BSA)的作用机制.实验表明,柠檬酸钠对BSA具有荧光猝灭作用,其猝灭方式为静态猝灭,并求出了猝灭常数、结合常数及结合位点数.     

同步荧光光谱法结合分子对接研究金雀花碱与牛血清白蛋白间相互作用

金雀花碱(Cy)是一种生物碱,主要存在于豆科毒豆属植物种子中。Cy具有较强的生物活性,特别是作为戒烟药物已得到广泛应用。在模拟生理条件下,应用荧光光谱法研究了Cy同牛血清白蛋白(BSA)之间的相互作用以及Cy猝灭BSA荧光发射的机理。详细考查了水浴温度、水浴时间以及溶液pH等因素对荧光猝灭的影响,并且通过Stem-Volmer方程计算了Cy与BSA间的结合类型、结合位点数目以及结合常数。结果表明,Cy与BSA可形成摩尔比为1∶1的非共价复合物,其结合常数为5.6×103,其猝灭类型为静态猝灭。同步荧光光谱研究结果表明,Cy的结合主要影响BSA 的Trp残基的荧光发射。进一步应用分子对接研究表明,氢键与疏水作用是Cy与BSA形成复合物的主要推动力。Cy与BSA中Trp213及其周围的氨基酸残基间存在氢键与疏水作用,这种作用将改变Trp213所处微环境的疏水情况,从而导致BSA的荧光发生猝灭。     

不同光谱法用于药物与蛋白相互作用的比较研究

在模拟人体生理环境下,利用荧光猝灭法(FQS)、同步荧光法(SYS)、共振光散射法(RLS)及紫外吸收光谱法(UV)分别研究了298 K下牛血清白蛋白与硫酸粘杆菌素、硫酸头孢匹罗、头孢匹胺钠3种药物间的相互作用机理。结果表明:对于相同的体系,利用4种方法计算得到的结合常数在同一数量级,猝灭方式均为生成新物质的静态猝灭,药物与蛋白作用时均以1∶1的比例结合,Hill系数近似。但对4种方法所得实验数据的综合比较表明,FQS、SYS更适合用于研究蛋白与药物的反应机理。     

Study of Organized Media Using Time-Resolved Fluorescence Spectroscopy

Many photophysical processes which occur on an ultrafast time scale in ordinary liquids become significantly retarded in organized assemblies, by two to three orders of magnitude. Recently many groups have applied ultrafast laser spectroscopy and theoretical methods to elucidate this dramatic phenomenon. Although the implications of this phenomenon in biology and chemistry are not yet fully understood, it has been demonstrated that ultrafast time-resolved fluorescence spectroscopy is a very powerful tool to study the microscopic properties of the organized assemblies and that water or other liquids confined inside these assemblies are fundamentally different from the corresponding liquid in bulk.     

Comparison of Detection Limits in Atomic Fluorescence and Absorption Spectroscopy

Dagnall, Taylor, and West have recently compared detection limits for a number of metals in atomic fluorescence and absorption spectroscopy and have concluded that “atomic fluorescence measurements using an electrodeless discharge tube are inherently more sensitive than those obtainable by atomic absorption measurements”. Likewise West and Williams have compared the two techniques for magnesium²and silver³, using high-intensity hollow-cathode lamps as sources, and have found much lower detection limits in fluorescence than in absorption.     

荧光光谱及其成像技术在光活检中的应用

分析了人体组织自体荧光的主要物质来源和荧光特性,同时总结了国内外常见的第二代新型光敏剂及其临床应用情况。在此基础上,全面比较了各种应用于早期肿瘤光活检的荧光光谱及其成像技术,并重点讨论了这些技术的基本原理和临床应用现状,以及它们今后的发展方向。     

Laser Induced Fluorescence Spectroscopy of IrN

利用激光蒸发/反应的自由射流膨胀和激光诱导荧光光谱方法,研究了IrN在394-520nm光谱区域的高分辨率激光诱导荧光光谱. 观察并分析了7个新的振动谱带. 确定了其中有两条是Ω=1和五条是Ω=0的新谱带. 用最小二乘法拟合了转动跃迁谱线,由此确定了高能级的精确光谱常数. 同位素分子光谱为振动光谱的标识提供了进一步的验证, 比较测得的IrB、IrC和IrN的电子态光谱推进了对这一系列分子的化学成键性质的认识.     

Determination of Protolytic Constants by Trilinear Fluorescence Spectroscopy

Protolytic equilibria often have profound effects on chemical activity, since protolytic species usually behave quite differently. It is therefore important to characterize the protolytic properties of important chemicals. Here we present a new approach to study protolytic equilibria of fluorescent species that is extremely accurate and relies on minimum assumptions. We show that by measuring 2-dimensional excitation/emission scans of samples at different pH. the 3-dimensional experimental data set, I(lambda(ex), lambda(em), C(pH)), can be unambiguously decomposed into the spectral responses of the protolytic species present as well as their concentration. The approach is demonstrated on the protolytic equilibrium of fluorescein. Although the fluorescein monoanion cannot be obtained in pure form, the spectra and concentrations of both fluorescein species, as well as the protolytic constant, are determined with excellent accuracy. The proposed method is general and can be applied not only for studies of protolytic equilibria, but on any chemical equilibria and chemical reactions involving fluorescent species.     

冷鲜猪肉的三维荧光光谱特征研究

利用三维荧光光谱技术,研究了冷鲜猪肉三维荧光光谱特征,主要探讨了不同温度存储条件下冷鲜猪肉荧光峰的位置和荧光峰所处区域内荧光强度平均值随存储时间变化的规律,并初步判断了荧光物质的种类,为实现基于三维荧光光谱技术快速、无损检测冷鲜猪肉新鲜度奠定了理论基础。实验结果表明,不同温度存储条件下样本的三维荧光光谱图中均含有2个明显的荧光峰（Peak A和Peak B）,它们所在位置的激发波长（λ_ex）/发射波长（λ_em）范围分别为：λ_ex/λ_em约为250～310 nm/300～400 nm和约为300～450 nm/400～550 nm。其中,Peak A为类蛋白荧光,Peak B为脂质氧化产物荧光。此外,实验还发现,两个荧光峰在各自所处区域内荧光强度的平均值随存储时间变化的趋势不受存储温度影响,均是Peak A在λ_ex/λ_em=250～310 nm/300～400 nm区域内荧光强度的平均值（I_A）逐渐下降,Peak B在λ_ex/λ_em=300～450 nm/400～550 nm区域内荧光强度的平均值（I_B）逐渐上升。但I_A和I_B的变化速率受存储温度影响,冷藏条件下比室温条件下变化慢。     

农田土壤水分含量的激光诱导荧光光谱表征

通过实验探讨了植物的激光诱导叶绿素荧光光谱与土壤水分间的关系。实验利用Y-形光纤探头获取了植物在450 nm LED光源照射下所发出的叶绿素荧光光谱,同时利用TDR传感器测量土壤湿度。实验以水稻为研究对象,研究了在持续水分胁迫和间歇水分胁迫下,叶绿素荧光光谱743 nm附近波峰的变化,结果发现,波峰强度与土壤水分含量具有相关性。最后,利用Lorentzian方程,将持续水分胁迫下的土壤含水量与叶绿素荧光强度进行建模,发现所建的模型具有较高的决定系数,说明该方法可以应用于农业生产中对土壤水分的测量。     

Time-Resolved Fluorescence Spectroscopy Study on the Photophysical Behavior of Quantum Dots

Room-temperature time-resolved luminescence measurements on single CdSe/ZnS quantum dots (QDs) are presented. Fluorescence emission spectra were recorded over periods of up to 30 minutes with a time resolution as small as 6 ms. For QDs in ambient air, a clear 30–40 nm blue shift in the emission wavelength is observed, before the luminescence stops after about 2–3 minutes because of photobleaching. In a nitrogen atmosphere, the blue shift is absent while photobleaching occurs after much longer times (i.e., 10–15 minutes). These observations are explained by photoinduced oxidation. The CdSe surface is oxidized during illumination in the presence of oxygen. This effectively results in shrinkage of the CdSe core diameter by almost 1 nm and consequently in a blue shift. The faster fading of the luminescence in air suggests that photoinduced oxidation results in the formation of non-radiative recombination centers at the CdSe/CdSeO_x interface. In a nitrogen atmosphere, photoinduced oxidation is prevented by the absence of oxygen. Additionally, a higher initial light output for CdSe/ZnS QDs in air is observed. This can be explained by a fast reduction of the lifetime of the long-lived defect states of CdSe QDs by oxygen.     

时间序列三维荧光光谱的数据压缩

时间序列三维荧光光谱数据量大和信息丰富的特点虽然有利于有机物的定性和定量分析,但是大量冗余信息的存在增加了计算的复杂度和计算量。在分析了时间序列三维荧光光谱的时频特征后,分别利用聚类分析和二维小波变换从时间维和光谱维对三维荧光光谱进行了压缩。在聚类分析中探讨了样本距离、类间距离、复合相关系数和R平方统计量等关键因素。相关系数和R平方统计量的结合不仅提高了聚类分析的精确度,而且减少了二维小波在光谱维进行数据压缩的工作量。相关的数值实验表明压缩后的数据保留了原有时间序列三维荧光光谱的重要信息。     

Fluorescence Correlation Spectroscopy of Gold Nanoparticles

Diffusion dynamics of gold nanoparticles (GNPs) was studied by fluorescence correlation spectroscopy (FCS). The fluorescence was studied by exciting the particles by green laser (532 nm), which is far from longitudinal plasmon band of nanorods. Transmission electron microscope (TEM) and UV-Vis-NIR spectrometer were used to characterize the gold nanoparticles. Despite their low quantum yields, GNPs possess the native fluorescence. The excellent antiphotobleaching behavior of gold nanorods leads to prospects of using FCS for its detailed studies. Using FCS, dynamic information can be extracted from the fluorescence fluctuations in the system by autocorrelation function. Maximum entropy method (MEMFCS) was used to identify the number of distinct components present in the system. The particle sizes obtained from FCS were found to be higher (by few orders of magnitude) compared to TEM analysis. This might be due to the possible contributions from cetyltrimethyl ammonium bromide (CTAB) capping in the system.