光谱技术研究硫堇与牛血清白蛋白的结合反应

用荧光光谱、紫外可见吸收光谱和圆二色光谱技术研究了生理条件下硫堇(TH)与牛血清白蛋白(BSA)的结合反应.结果表明,硫堇借静电力与牛血清白蛋白发生相互作用并对牛血清白蛋白的荧光以静态方式猝灭,其结合常数为1.155×105L·mol-1、结合位点数为1.835、结合距离2.865 nm.同步荧光和圆二色技术证实TH对BSA的构像有影响.     

人血清白蛋白和菁染料的相互作用研究

研究菁染料分子DMSA与人血清白蛋白(HSA)之间的相互作用及DMSA对HSA构象的影响。采用荧光光谱研究菁染料DMSA与HSA的相互作用机制,通过计算结合常数和结合位点确定荧光猝灭类型;利用吸收光谱和同步荧光光谱探讨DMSA对HSA构象的影响。结果表明菁染料DMSA能猝灭HSA的内源性荧光,其猝灭机制为静态猝灭且DMSA与HSA之间具有很强的结合能力,结合常数Ka=7.73×106L·mol-1,结合位点n=1.59。此外,通过吸收光谱和同步荧光光谱探讨了DMSA对HSA构象的影响,DMSA的加入使HSA的结构变得疏松导致构象发生变化。     

芦丁铕配合物与人血清白蛋白的相互作用

在模拟动物体生理pH条件下,用荧光光谱法(FS)和电化学法研究了芦丁铕配合物(rutin-Eu)与人血清白蛋白(HSA)的结合反应.探讨了rutin-Eu对HSA的荧光猝灭过程的猝灭机理,以Lineweaver-Burk双倒数方程分别计算了不同温度下rutin-Eu与HSA的结合常数(KLB,295K:1.540×106L/mol,310K:1.265×106L/mol)、结合距离(r=2.28nm)和热力学参数(△Η=-9.97kJ/mol;295K:△S=84.64J/K,△G=-34.94kJ/mol;310K:△S=84.65J/K;△G=-36.21kJ/mol),并判断rutin-Eu与HSA结合的作用力类型;同时用圆二色谱及同步荧光光谱法探讨了rutin-Eu对HSA构象的影响.结果表明,rutin-Eu与HSA结合形成复合物,导致HSA内源性荧光猝灭是由于分子内的非辐射能量转移而引起的静态猝灭;它们之间的主要作用力是静电作用力而结合距离r为2.28nm.同步荧光光谱法和圆二色谱法表明rutin-Eu对HSA的构象有影响,可使HSA的二级结构发生改变.     

基于光谱法研究汞荧光分子探针与人血清白蛋白的相互作用

采用荧光光谱技术,研究了不同温度下用于识别汞的荧光分子探针（WL-6）与生物大分子人血清白蛋白（HSA）的结合机理。结果表明,HSA在结合位点的荧光强度,随着WL-6的浓度增加而显著降低。根据荧光数据,得到了WL-6与HSA作用的结合常数、主要作用力及猝灭常数。从紫外吸收光谱、荧光光谱、同步荧光、三维荧光光谱和圆二色谱的结果可以看出,WL-6的结合改变了HSA的构象。     

一种新型含硒席夫碱与人血清白蛋白相互作用的研究

应用紫外吸收光谱和荧光光谱研究了新型含硒席夫碱2-苄基亚胺基次甲基-4-(3-苄基亚胺基次甲基-4-羟基-苯硒基)苯酚(BBHP)与人血清白蛋白(HSA)之间的相互作用.结果表明,在生理pH值条件下BBHP主要通过形成复合物的静态猝灭方式使HSA的内源荧光得以强烈猝灭;BBHP与HSA主要有1个结合位点数,298 K时的结合常数为1.392×106 L·mo1-1;该结合反应为自发的放热过程,相互作用力主要为氢键和范德华力.根据F(o)rster无辐射能量转移理论计算了两者之间的结合距离r=2.42 nm,同时考察了BBHP对HSA构象的影响.     

2,4-二氯苯酚与人血清白蛋白相互作用的研究

在模拟人体生理条件下,利用荧光光谱法、紫外吸收光谱法、圆二色谱法和三维荧光光谱法等方法研究了2,4-二氯苯酚(DCP)与人血清白蛋白(HSA)的相互作用.结果表明,DCP使HSA的荧光强度发生了静态猝灭.根据修正的Stern-Volmer方程,求出DCP与HSA在292 K、298 K、304 K、310 K下的有效猝...     

硼酯类荧光探针与人血清白蛋白相互作用的研究

采用荧光光谱法、三维荧光光谱、CD光谱及同步荧光,研究了硼酯类荧光探针(JYS-1)与人血清白蛋白(HSA)的作用机理和探针对HSA构象的影响.由实验结果可知,HSA与探针之间的猝灭方式主要是静态猝灭方式.根据热力学数据,确定了二者之间的结合距离为3.07nm,二者之间在298K、305及308K时的结合常数,分别为2...     

黄腐酸与人血清白蛋白相互作用机制的光谱研究

<正>利用荧光光谱研究黄腐酸(FA)与人血清白蛋白(HSA)的相互作用,二者有明显的荧光猝灭作用,计算二者作用的结合常数(Ka=1.2×107 L/mol)、结合位点数(n=1.45)及结合距离(r0=2.92 nm)。二者的猝灭机制属于静态猝灭,并发生分子内非辐射能量     

光谱法研究铜离子荧光探针与人血清白蛋白的相互作用

运用紫外以及荧光光谱对铜离子荧光探针(DQX-1)与人血清白蛋白的相互作用进行了研究。结果表明,此探针与HSA结合,形成复合物,探针能够有规律的猝灭HSA的荧光,猝灭机理证明为静态猝灭。由两者之间的相互作用力,判别出:探针DQX-1和HAS之间发生自动的结合,主要依靠的作用力是氢键和范德华力。通过探针DQX-1和HAS之间的结合距离为5.42 nm,说明两者之间能够发生非辐射能量的转移。同步荧光和三维荧光光谱数据表明,加入DQX-1后HSA的构象也发生变化。     

光谱法研究铜离子荧光探针与人血清白蛋白的相互作用

运用紫外以及荧光光谱对铜离子荧光探针(DQX-1)与人血清白蛋白的相互作用进行了研究。结果表明,此探针与HSA结合,形成复合物,探针能够有规律的猝灭HSA的荧光,猝灭机理证明为静态猝灭。由两者之间的相互作用力,判别出:探针DQX-1和HAS之间发生自动的结合,主要依靠的作用力是氢键和范德华力。通过探针DQX-1和HAS之间的结合距离为5.42 nm,说明两者之间能够发生非辐射能量的转移。同步荧光和三维荧光光谱数据表明,加入DQX-1后HSA的构象也发生变化。     

Vibrational Spectroscopy in Assessment of Early Osteoarthritis—A Narrative Review

Osteoarthritis (OA) is a degenerative disease, and there is currently no effective medicine to cure it. Early prevention and treatment can effectively reduce the pain of OA patients and save costs. Therefore, it is necessary to diagnose OA at an early stage. There are various diagnostic methods for OA, but the methods applied to early diagnosis are limited. Ordinary optical diagnosis is confined to the surface, while laboratory tests, such as rheumatoid factor inspection and physical arthritis checks, are too trivial or time-consuming. Evidently, there is an urgent need to develop a rapid nondestructive detection method for the early diagnosis of OA. Vibrational spectroscopy is a rapid and nondestructive technique that has attracted much attention. In this review, near-infrared (NIR), infrared, (IR) and Raman spectroscopy were introduced to show their potential in early OA diagnosis. The basic principles were discussed first, and then the research progress to date was discussed, as well as its limitations and the direction of development. Finally, all methods were compared, and vibrational spectroscopy was demonstrated that it could be used as a promising tool for early OA diagnosis. This review provides theoretical support for the application and development of vibrational spectroscopy technology in OA diagnosis, providing a new strategy for the nondestructive and rapid diagnosis of arthritis and promoting the development and clinical application of a component-based molecular spectrum detection technology.     

Raman and Infrared Imaging of Dynamic Polymer Systems

This work reviews principles of Raman and infrared imaging, as well as applications of the art to understand physiochemical phenomena in polymer systems. Image sequences may be assessed in terms of spatial or spectral changes that occur over time, either within a specific region or across the field of view. As such, the methods have enabled the analysis of diffusion and dissolution processes at polymer interfaces, drug release from polymer matrices, and structural transitions among others. Despite analytical limitations imposed by resolution (spectral or spatial) and sample preparation, Raman and infrared imaging are powerful tools for relating performance attributes to molecular‐level characteristics.

     

Infra-red and Raman spectroscopic study on the thermal stability and high temperature transformation of hydroazafullerene C59HN

Hydroazafullerene C₅₉HN was studied by vibrational infra-red and Raman spectroscopy and its thermal stability was examined. Fingerprints modes were identified and unambiguously differentiate it from bisazafullerene. At 700 K full transformation to bisazafullerene occurred, while an intermediate metastable phase was identified at 540 K showing different spectra where the splitting of most of the lines is strongly reduced.     

State of C-atoms on the modified nanodiamond surface

XPS, EEL, Auger and FTIR spectroscopies were used to testify the influence of chemical treatment upon the state of C-atoms in the core and on the surface of nanodiamond particles. The study was carried out with ND (JSC “Diamond Centre”). The different kinds of treatments were done ex-situ: with air (5 h) at 200 and 400 °C; with hydrogen (5 h) at 800, 850 and 900 °C; with fluorine (48 h) at 20 °C and 0.5 atm. Noticeable change was not found in the state of C-atoms both on the surface and up to 10 monolayers after these treatments. The concentration of F in the sample is equal to  9 at.%. The binding energy of the F 1s differs from the one in functional groups— –CF₂, –CF. Nevertheless FTIR spectra show bands that can be related to С–О, С–F bonds.     

Phosphatidylethanolamine‐Binding Proteins,Including RKIP,Exhibit Affinity for Phosphodiesterase‐5 Inhibitors

Identifying protein “interactors” of drugs is of great importance to understand their mode of action and possible cross‐reactivity to off‐target protein binders. In this study, we profile proteins that bind to PF‐3717842, a high‐affinity phosphodiesterase‐5 (PDE5) inhibitor, by using a refined affinity pulldown approach with PF‐3717842 immobilized beads. By performing these pulldowns in rat testis tissue lysate, we strongly and specifically enriched for PDE5 and a few other PDEs. In addition to these expected affinity‐enriched proteins we also detect rodent‐specific phosphatidylethanolamine‐binding protein 2 (PEBP2), as a putative binder to the PDE5 inhibitor. By using recombinant forms of the related murine mPEBP2, mPEBP1 and human hPEBP1 (also known as Raf kinase inhibitor protein or RKIP) we confirm that they all can bind strongly to immobilized as well as soluble PF‐3717842. As the phosphatidylethanolamine‐binding proteins are involved in various important signal transduction pathways, the synthetic PDE5 inhibitor used here might form a platform to synthesize enhanced binders/inhibitors of the family of PEBP proteins. Our approach shows how chemical proteomics might be used to profile the biochemical space (interactome) of small molecule inhibitors.     

Theoretical and Experimental Spectroscopic Analysis of Cyano-Substituted Styrylpyridine Compounds

A combined theoretical and experimental study on the structure, infrared, UV-Vis and ¹H NMR data of trans-2-(m-cyanostyryl)pyridine, trans-2-[3-methyl-(m-cyanostyryl)] pyridine and trans-4-(m-cyanostyryl)pyridine is presented. The synthesis was carried out with an efficient Knoevenagel condensation using green chemistry conditions. Theoretical geometry optimizations and their IR spectra were carried out using the Density Functional Theory (DFT) in both gas and solution phases. For theoretical UV-Vis and ¹H NMR spectra, the Time-Dependent DFT (TD-DFT) and the Gauge-Including Atomic Orbital (GIAO) methods were used, respectively. The theoretical characterization matched the experimental measurements, showing a good correlation. The effect of cyano- and methyl-substituents, as well as of the N-atom position in the pyridine ring on the UV-Vis, IR and NMR spectra, was evaluated. The UV-Vis results showed no significant effect due to electron-withdrawing cyano- and electron-donating methyl-substituents. The N-atom position, however, caused a slight change in the maximum absorption wavelengths. The IR normal modes were assigned for the cyano- and methyl-groups. ¹H NMR spectra showed the typical doublet signals due to protons in the trans position of a double bond. The theoretical characterization was visibly useful to assign accurately the signals in IR and ¹H NMR spectra, as well as to identify the most probable conformation that could be present in the formation of the styrylpyridine-like compounds.     

Spectroscopic Studies of Model Photo-Receptors: Validation of a Nanosecond Time-Resolved Micro-Spectrophotometer Design Using Photoactive Yellow Protein and α-Phycoerythrocyanin

Time-resolved spectroscopic experiments have been performed with protein in solution and in crystalline form using a newly designed microspectrophotometer. The time-resolution of these experiments can be as good as two nanoseconds (ns), which is the minimal response time of the image intensifier used. With the current setup, the effective time-resolution is about seven ns, determined mainly by the pulse duration of the nanosecond laser. The amount of protein required is small, on the order of 100 nanograms. Bleaching, which is an undesirable effect common to photoreceptor proteins, is minimized by using a millisecond shutter to avoid extensive exposure to the probing light. We investigate two model photoreceptors, photoactive yellow protein (PYP), and α-phycoerythrocyanin (α-PEC), on different time scales and at different temperatures. Relaxation times obtained from kinetic time-series of difference absorption spectra collected from PYP are consistent with previous results. The comparison with these results validates the capability of this spectrophotometer to deliver high quality time-resolved absorption spectra.     

A study by Raman, near-infrared and dynamic-mechanical spectroscopies on the curing behaviour, molecular structure and viscoelastic properties of epoxy/anhydride networks

The curing characteristics of a TGDDM/HHPA formulation have been investigated by Raman spectroscopy, which allowed us to monitor the evolution of the different reactive species (i.e. epoxy, anhydride and ester groups) participating in the curing process. The curing mechanism and, in particular, the role of side processes, were elucidated. NIR spectroscopy was employed to investigate the post-curing process, in view of the superior sensitivity of this technique for monitoring polar groups. Quantitative methods were developed to measure residual concentration of epoxy groups in the high conversion regimes (≥98%). Dynamic-mechanical measurements were performed to gather information on the molecular structure and viscoelastic properties of the investigated networks. For formulation rich in epoxy resin, clear evidence of an inhomogeneous phase structure was found. A viscoelastic analysis in terms of the WLF approach demonstrated that both the free volume and the thermal expansion coefficient of the networks decrease by enhancing the anhydride/epoxy molar ratio.     

Monitoring of polymer content in an emulsion polymerization using spatially resolved spectroscopy in the near infrared region and Raman spectroscopy

The potential of spatially resolved spectroscopy (SRS) for in situ monitoring is evaluated in this work. SRS is based on near-infrared spectroscopy. It is well adapted to heterogeneous systems and collects information about both physical and chemical properties. In this work, the polymer content in emulsion copolymerization is predicted using SRS. The reaction was first carried out in batch mode for particle nucleation followed by semi-continuous monomer addition under starved conditions to allow particle growth. SRS and Raman spectroscopy are compared, and the advantages and disadvantages of both methods are highlighted, revealing that each method has its own benefits. Different operating conditions were varied, including the monomer ratio, the surfactant mass fraction, and the agitation speed. Regression models were developed using partial least square for both techniques.