酞菁与TiO2微粒间的光诱导电子转移相互作用

带有负电荷取代基的四磺化酞菁化合物与TiO2超微粒在溶液中通过静电相互吸引,能够形成基态复合物。通过吸收光谱和荧光光谱,计算了磺化酞菁与TiO2在溶液中的表现缔合平衡常数K.与相应的烷氧基取代酞菁化合物作比较,并通过单光子技术测定染料荧光寿命。结合荧光光谱,证明了磺化酞菁与TiO2在溶液中的缔合作用,有利于激发态酞菁染料向半导体TiO2的导带注入电子,从而发生分子间的电子转移反应,将磺化酞菁吸附在TiO2纳晶薄膜电极上,进行光电性能测试。结果表明,染料敏化TiO2纳晶薄膜电极光电响应的大小与染料在电极表面吸附的强弱有关。     

酞菁与TiO2超微粒间的光诱导电子转移相互作用

带有负电荷取代基的四磺化酞菁化合物与 TiO2超微粒在溶液中通过静电相互吸引 ,能够形成基态复合物 .通过吸收光谱和荧光光谱 ,计算了磺化酞菁与 TiO2在溶液中的表观缔合平衡常数 K.与相应的烷氧基取代酞菁化合物作比较 ,并通过单光子计数技术测定染料荧光寿命 .结合荧光光谱 ,证明了磺化酞菁与 TiO2在溶液中的缔合作用 ,有利于激发态酞菁染料向半导体 TiO2的导带注入电子 ,从而发生分子间的电子转移反应 .将磺化酞菁吸附在 TiO2纳晶薄膜电极上 ,进行光电性能测试 .结果表明,染料敏化 TiO2纳晶薄膜电极光电响应的大小与染料在电极表面吸附的强弱有关 .     

甲磺基铝酞菁与爱尔新蓝的缔合作用在核酸定量中的应用

阴离子荧光染料四磺基铝酞菁与阳离子荧光染料爱尔新蓝的缔合作用，使四磺基铝酞菁发生荧光猝灭，而当核酸存在时，染料缔合平衡受到影响而导致四磺基铝酞菁的荧光恢复。根据这一原理，建立了核酸定量测定的新方法。方法具有很高的灵敏度和较好的选择性，其线性范围为0-200цg/L；检测限分别为1.8цg/L(SMDNA)、2.0цg/L(CTDNA)、5.4цg/L（酵母RNA）。将方法用于实际样品金黄色葡萄球菌中DNA含量的测定，获得满意结果。     

四磺基铝酞菁与爱尔新蓝的缔合作用在核酸定量中的应用

阴离子荧光染料四磺基铝酞菁与阳离子荧光染料爱尔新蓝的缔合作用 ,使四磺基铝酞菁发生荧光猝灭 ,而当核酸存在时 ,染料缔合平衡受到影响而导致四磺基铝酞菁的荧光恢复。根据这一原理 ,建立了核酸定量测定的新方法。方法具有很高的灵敏度和较好的选择性 ,其线性范围为 0～ 2 0 0 μg/L ;检测限分别为 1.8μg/L(SMDNA)、2 .0 μg/L(CTDNA)、5 .4μg/L(酵母RNA)。将方法用于实际样品金黄色葡萄球菌中DNA含量的测定 ,获得满意结果     

磺化酞菁在甲醇-水溶液中的二聚作用研究

研究了不同磺化度的酞菁在甲醇－水混合溶剂中的聚集行为，通过紫外－可见光谱测定，发现磺化度在１．０以上的时染料在稀溶液中主要单体和二聚体的形式存在，并可用简单的方法计算出聚集平衡常数和平衡时单体所占的百分化，得到磺化越低越易聚集的结论，有关激发态的实验表明，增加酞菁磺化度有助于提高表观荧光量子产率，但对荧光寿命影响较小。     

磺化2,3-萘酞菁锌(Ⅱ)、钴(Ⅱ)的电子吸收光谱和荧光光谱的研究

研究了磺化2，3-萘酞菁锌(Ⅱ)、钴(Ⅱ)在DMF(N，N-二甲基甲酰胺)、DMSO(二甲基亚砜)、乙醇、水等溶剂中的电子吸收光谱和荧光光谱．萘酞菁配合物的Q带与相应的酞菁配合物Q带相比，电子吸收光谱红移80～90nm，荧光光谱红移约100nm，荧光强度也显增加．在金属萘酞菁中引入磺酸基，配合物的电子吸收光谱Q带发生红移，但是影响不大、对于相同中心金属的配合物，改变溶剂的种类对配合物的电子吸收光谱的Q带影响较大．在金属萘酞菁环上引入一个磺酸基时，在相同溶剂中与无取代萘酞菁相比发生荧光光谱Q带红移，荧光强度增大．但在萘酞菁环上继续引入磺酸基时，荧光强度反而减少．磺化萘酞菁钴比磺化萘酞菁锌有较大的荧光强度．不同浓度下的电子吸收光谱和荧光光谱说明金属萘酞菁有集聚倾向、能形成基激缔合物．     

磺化酞菁与人血清白蛋白复合物的光动力活性研究

通过光谱法研究了三种磺化酞菁(α位四磺化酞菁、β位四磺化酞菁和α位单取代磺化酞菁)与人血清白蛋白(HSA)的相互作用.结果 表明,HSA对α位四磺化酞菁的存在状态(单体、聚集体)影响显著,而对β位四磺化酞菁和α位单取代磺化酞菁的存在状态没有明显影响.磺化酞菁与HSA均存在明显的相互作用,且.四磺化酞菁与HSA的结合作用...     

磺化锌酞菁与胶束间的相互作用

用吸收光谱和荧光光谱研究了不同磺化程度酞菁与不同胶束间的相互作用并计算了结合常数。低磺化程度酞菁与三类胶束间均可发生相互作用,其标志是胶束的解聚作用;而高磺化程度酞菁与此显著不同,可结合在阳离子胶束表面,与非离子胶束无明显作用,而阴离子胶束对磺化酞菁只起促聚作用。用磺化程度变化导致酞菁分子体积、电荷及疏水性变化解释了实验结果。     

磺化酞菁类染料光敏氧化胆固醇及L-半胱氨酸的反应

本文合成了磺化酞菁、磺化酞菁镓和磺化酞菁铝,研究了它们光敏氧化胆固醇及L-半胱氨酸的反应。染料的聚集态和溶液的pH值对反应速率有不同程度的影响。D₂O加速反应而NaN₃猝灭反应的结果表明,光敏氧化反应主要通过Ⅱ型(涉及¹O₂)机制进行。     

对四-2,3-吡啶并紫菜嗪铬的薄膜电极的光电化学研究

由于叶绿素具有较高的光能转换效率,使许多人对类似于叶绿素结构的酞菁染料产生了兴趣,本文所研究的对四-2,3-吡啶并紫菜嗪铬的薄膜(PcCrPy)就是酞菁类(CrPy)染料的苯环用吡啶环取代的衍生物,从而使染料容易电沉积到各种支持导体上。已有不少人对酞菁的薄膜进行过电化学和光电化学的研究,但几乎没有人对PcCrPy进行过光电化学的研究。我们已对PeCrPy进行了原位吸收光谱研究和原位拉曼光谱研究。本文将对     

Studies on the Binding Mode of Pinacyanol Chloride to Nucleic Acids

The interaction of pinacyanol chloride(PC) with nucleic acids has been investigated by a series of experiments.Extensive hypochromism,appreciable peak shifts,isosbestic points and new peaks of the product of binding to nucleic acids in the spectra were observed.They showed that the interaction between PC and nucleic acids occurred.The results from absorption spectra of DNA,DNA melting,electrophoresis and fluorescence polarization studies have indicated that PC binds to DNA in nonintercalative way.Consistent with the nonintercalation,the studies of fluorescence titration and absorption titration specified that the binding of PC to nucleic acids occurred by an outside stacking binding,in which nucleic acids served for acting templates,The fact that the new absorption peaks of bound PC at ca,485nm are just close to the absorption bands of Haggregate of PC at high concentrations without DNA further supports the outside stacking binding mode,In addition,other evidence indicated that the interaction between PC and nucleic acids is not purely electrostatic.     

Study of the Reaction between Nucleic Acids and Tb-BPMPHD-CTMAB Complex and its Analytical Application

The direct use of the fluorescence emission properties of nucleic acids in the investigation of their biological properties is limited, whereas the use of metal complexes as fluorescence probe to study nucleic acids has increased remarkbly. Recently we found that the Tb-l,6-bi(1'-phenyl-3'-methyl-5'-pyrazolone-4'-)hezane-dione(BPMPHD)-trimethyl am-monium bromide(CTMAB) complex can be used as a sensitive fluorescence probe for the determination of nucleic acids.     

Complex formation between tryptophan-containing peptides and nucleic acids: Fluorescence decay studies using synchrotron radiation

Synchrotron radiation has been used to determine the fluorescence decay parameters of a tryptophan-containing oligopeptide, Lys-Trp-Lys, bound to nucleic acids. All fluorescence decay curves can be fitted by a sum of two exponentials. The two lifetimes very likely correspond to two conformational states of the oligopeptide. The mean fluorescence lifetime of the peptide is not markedly affected upon binding to nucleic acids even though the fluorescence quantum yield is strongly reduced. A model is presented that accounts for the existing fluorescence data: two consecutive complexes are formed both involving electrostatic interactions. In one of the complexes the tryptophyl ring is stacked with the nucleic acid bases and its fluorescence is completely quenched. The other complex emits a fluorescence having characteristics which are similar to those of the free peptide.     

A kinetic fluorometric method for the determination of nucleic acids using a ternary equilibrium system of nucleic acids—iron (III) tetracarboxy phthalocyanine-poly-lysine coupled with the oxidation reaction between hydrogen peroxide and dl-tyrosine

Using the oxidation reaction between hydrogen peroxide and dl-tyrosine as fluorescence indication, the evident tuning effect of nucleic acids on catalytic activity of mimetic enzyme iron (III) tetracarboxy phthalocyanine (FeC₄Pc) in the presence of poly-lysine was observed and studied. The oxidation reaction between hydrogen peroxide and dl-tyrosine with FeC₄Pc as catalyst gave an intensively fluorescent compound, which has an excitation wavelength of 325 nm and an emission wavelength of 418 nm. The fluorescence was quenched by a proper concentration of poly-lysine due to its association with FeC₄Pc and consequently the descent of the catalytic activity of FeC₄Pc, but recovered by addition of nucleic acids. Under optimal conditions, the recovered fluorescence is proportional to the concentration of nucleic acids. Based on the fact, a kinetic fluorescent method was developed for the determination of nucleic acids. The calibration graphs are linear over the range 10-2000 ng/mL both for fish sperm DNA (FS DNA) and calf thymus DNA (CT DNA). The corresponding detection limits are 1.04 ng/mL for FS DNA and 1.18 ng/mL for CT DNA, respectively. Four synthetic and three real nucleic acid samples were determined with satisfactory results.     

姜黄素-La3+-CTMAB-核酸体系的荧光增强效应及其应用

研究了镧离子(La3+)-姜黄素(CU)-十六烷基三甲基溴化铵(CTMAB)-核酸荧光增强体系.建立了测定核酸的新方法.体系的最优条件为:六次甲基四胺(HMTA)-HCl缓冲溶液(pH 5.80)中,1.00× 10-3 mol/L阳离子表面活性剂CTMAB存在下,姜黄素浓度为2.00×10-5 mol/L,La3+的浓度为1.40×10-4 mol/L时,核酸能增强La3+ -CU络合物的荧光强度,而且体系荧光的增强程度与核酸的加入量在一定范围内呈线性关系.fsDNA,ctDNA和yRNA线性范围分别为7.00×10-4～10.00 mg/L,4.00×10-4～10.00 mg/L和7.00×10-4～10.00 mg/L;检出限分别为0.17,0.02和0.14 μg/L.与已报道的核酸的分析方法相比,本方法具有较宽的线性范围和较高的灵敏度.研究表明,核酸对体系荧光的增强源于DNA主链上PO3-4与CU之间的静电结合,以及通过氢键和疏水力进行的沟槽式结合,为探针分子提供了疏水性的微环境,降低了体系的非辐射能量损失,使体系的荧光强度增加.     

A novel spectrofluorimetric method for the determination of DNA

A new simple, selective and sensitive fluorescence quenching method was developed to determine nucleic acids (DNA) with the 9-anthracenecarboxylic acid (ACA)-cetyl trimethyl-ammonium bromide (CTAB) system. The fluorescence intensity of ACA was decreased by the addition (CTAB). However, the fluorescence intensity of the system increased dramatically when DNA was added to the solution. The fluorescence enhancement is probably based on the DNA interaction with CTAB. Under the optimum conditions, the changes of fluorescence intensity in the absence and presence of nucleic acids was proportional to the concentration of nucleic acids over the range 0.08-1.0 microg mL(-1) for CT (calf thymus) DNA or FS (fish sperm) DNA. Its detection limits are 0.02 microg mL(-1) for CT DNA and 0.019 microg mL(-1) for FS DNA. Based on this approach, a new quantitative method for DNA assay is presented in this paper.     

Nucleic acids induced peptide-based AIE nanoparticles for fast cell imaging

Herein, we utilized nucleic acids induced peptide co-assembly strategy to develop novel nucleic acids induced peptide-based AIE (NIP-AIE) nanoparticles. Strong fluorescent of AIE could be observed when a little amount of nucleic acids was added into the peptide solution, and the intensity could be regulated by the concentration of nucleic acids. This AIE nanoparticle with good biocompatibility could achieve fast cell imaging. It is also proved that the fluorescence intensity of AIE decreased with time, which indicates that the reducible cross-linkers of Wpc peptide by GSH and nanoparticles gradually disintegrate in cell. Based on the different of AIE fluorescence signals which regulated by the formation and disintegration of nanoparticles, this AIE system is expected to be used for real-time monitoring of drug release from peptide-based nano carriers in vivo or in vitro, and may provide a new platform for the construction of other organic AIE nanoparticles.     

Nucleic acid-based fluorescent probes and their analytical potential

It is well known that nucleic acids play an essential role in living organisms because they store and transmit genetic information and use that information to direct the synthesis of proteins. However, less is known about the ability of nucleic acids to bind specific ligands and the application of oligonucleotides as molecular probes or biosensors. Oligonucleotide probes are single-stranded nucleic acid fragments that can be tailored to have high specificity and affinity for different targets including nucleic acids, proteins, small molecules, and ions. One can divide oligonucleotide-based probes into two main categories: hybridization probes that are based on the formation of complementary base-pairs, and aptamer probes that exploit selective recognition of nonnucleic acid analytes and may be compared with immunosensors. Design and construction of hybridization and aptamer probes are similar. Typically, oligonucleotide (DNA, RNA) with predefined base sequence and length is modified by covalent attachment of reporter groups (one or more fluorophores in fluorescence-based probes). The fluorescent labels act as transducers that transform biorecognition (hybridization, ligand binding) into a fluorescence signal. Fluorescent labels have several advantages, for example high sensitivity and multiple transduction approaches (fluorescence quenching or enhancement, fluorescence anisotropy, fluorescence lifetime, fluorescence resonance energy transfer (FRET), and excimer-monomer light switching). These multiple signaling options combined with the design flexibility of the recognition element (DNA, RNA, PNA, LNA) and various labeling strategies contribute to development of numerous selective and sensitive bioassays. This review covers fundamentals of the design and engineering of oligonucleotide probes, describes typical construction approaches, and discusses examples of probes used both in hybridization studies and in aptamer-based assays.     

基于酶催化反应的核酸定量新方法

近年来 ,将染料自缔合或诱导缔合用于核酸定量测定备受关注 [1～ 3 ] .但是将酶与染料的缔合用于核酸定量测定尚未见报道 .氯化血红素 (hemin)可作为辣根过氧化物酶 (HRP)的模拟酶 ,能催化 H2 O2氧化对 -羟基苯乙酸 (p- HPA)生成荧光产物——联二对 -羟基苯乙酸的反应 [4 ,5] .由于 hemin在碱性介质中是阴离子化合物 ,能与阳离子化合物如阿尔新蓝 (Alcian Blue 8GX)发生缔合作用 ,从而使自身的催化性质被抑制 .当加入带负电荷的脱氧核糖核酸 (DNA)时 ,由于阿尔新蓝与 DNA的强烈作用使hemin与阿尔新蓝的缔合物被破坏 ,hemin的催化活…     

Cationic conjugated polymers as signal reporter for label-free assay based on targets-mediated aggregation of perylene diimide quencher

Herein, we reported a cationic conjugated polymers-based new biosensor with label-free and fluorescence turn-on strategy by virtue of targets regulated aggregation and quenching ability of perylene diimide derivatives.