丹酰氯SiO2纳米发光标记物的制备

通过合成丹酰氯的荧光单体硅酯前驱物,采用油包水的反相微乳液法,以丹酰氯的荧光单体硅酯前驱物为核材料,成功地制备了丹酰氯的荧光纳米颗粒,克服了传统方法制备核壳荧光纳米颗粒中存在的荧光染料泄漏问题.通过透射电子显微镜表征该纳米粒子呈球形,大小均匀,直径为40nm左右.所制得纳米颗粒荧光性质稳定,受外界环境的影响小,且潜在生物亲和性,是一种新型的荧光标记物.     

荧光光谱法研究头孢呋辛酯与牛血清白蛋白的相互作用

用荧光光谱法研究了头孢呋辛酯(Cefuroximeaxetil)与牛血清白蛋白(BSA)的相互作用机制。结果表明在人体生理条件下头孢呋辛酯对牛血清白蛋白具有荧光猝灭作用且为动态猝灭过程,根据Stern-Volmer方程求出了两者的猝灭常数,并依据Foster能量转移理论确定了药物与蛋白的结合距离。     

二对硝基苯酯与β-环糊精相互作用的光谱学研究

以二环己基碳二亚胺(DCC)为脱水剂,使有关脂肪族二酸与对硝基苯酚缩合,合成了丁二酸二对硝基苯酯、己二酸二对硝基苯酯和癸二酸二对硝基苯酯等3种具有不同长度碳链的二酸二对硝基苯酯。利用红外光谱、质子核磁共振、元素分析、差示扫描量热等手段确证了酯的组成和结构。在此基础上以荧光猝灭、荧光光谱、紫外-可见光谱等技术系统研究了3种二酯与β-环糊精(β-CD)之间的主客体相互作用。结果表明：随二酯中二酸碳链增长,二酯与β-CD发生主客体作用的难度增加。实验条件下,丁二酸二对硝基苯酯分子中两个对硝基苯基结构均可进入β-CD疏水内腔,己二酸二对硝基苯酯分子中只有一个对硝基苯基结构可以进入β-CD疏水内腔,而癸二酸二对硝基苯酯分子中的两个对硝基苯基结构都不能进入β-CD疏水内腔,这种现象产生的原因可能是由于3种二酯在水溶液中采取了不同的构象。因此,碳链较短的二酸二对硝基苯酯可能比较适合于构筑基于主客体相互作用的三维网状结构。     

蒽类荧光染料的荧光性质及其化学发光效应

本文报道了蒽中位取代的荧光染料（9,10-二苯基蒽,9,10-二苯乙炔基蒽）的合成。分析测试了这类染料的液相荧光和化学发光光谱,讨论了它们的结构与其荧光和化学发光波长及效率的关系（在双乙二酸酯化学发光体系中）,并配制了发光明亮的高效化学发光液。     

染料木素酯化修饰物与牛血清白蛋白的相互作用

在模拟人体生理条件下(pH＝7.4),利用荧光光谱和紫外分光光度法研究了染料木素7-乙酰阿魏酸酯(1)和染料木素7,4’-二-乙酰阿魏酸酯(2)两种新型染料木素酯化修饰物,与牛血清白蛋白(BSA)的相互作用。实验表明：两种染料木素阿魏酸酯均能有效猝灭BSA的内源荧光,低浓度时为静态猝灭过程。考察了不同温度下化合物与BSA的结合常数和结合位点数。根据反应热力学参数确定了BSA与1之间主要为静电力作用,与2之间主要为氢键和范德华力作用。根据Frster 非辐射能量转移理论,BSA(给体)与化合物(受体)间的结合距离r分别为2.63和2.92 nm。同步荧光光谱法研究表明,染料木素乙酰阿魏酸酯与BSA的结合不影响蛋白质的构象,结合位点更接近于色氨酸。     

POSS-P(NIPAm-co-NBDAE)的可控合成及其荧光响应行为

采用3-苄基三硫代碳酸酯基丙酸(BSPA)对氨丙基七异丁基笼型倍半硅氧烷(POSS-NH_2)进行修饰,制备了POSS杂化RAFT试剂(POSS-BSPA);以4-氯-7-硝基-2,1,3-苯并噁二唑(NBDCl)为母体染料,合成4-(2-丙烯酸胺乙基酯)-7-硝基-2,1,3-苯并噁唑(NBDAE)荧光单体;以POSS-BSPA引发N-异丙基丙烯酰胺(NIPAm)和NBDAE进行可逆加成-断裂链转移(RAFT)聚合,合成了一种POSS杂化荧光温敏大分子POSS-P(NIPAm-co-NBDAE)。采用FTIR、~1H NMR、GPC对反应过程和产物结构进行了表征。采用PL光谱分别研究了在水和四氢呋喃(THF)中环境温度与F~-对它的荧光响应行为,并探讨了相关机理。结果表明,温度对其在水溶液中的荧光发射具有明显影响,在THF中其荧光发射几乎不受温度影响;F~-对其在水中的荧光发射影响相对较小,而对其在THF中的荧光猝灭十分显著。     

基于荧光光谱的茶汤中拟除虫菊酯类农药的智能识别

基于三维荧光光谱和二维荧光相关光谱,对茶汤中两种拟除虫菊酯农药进行了识别。利用图像局部极值算法,分别提取出三维荧光光谱图和二维相关光谱图中的峰、谷位置信息,然后进行峰位匹配实现茶汤中农药组分的智能识别。结果表明,三维荧光光谱图受到荧光峰重叠的影响,不能对氰戊菊酯进行有效匹配。而利用二维相关光谱不仅可以克服这一缺点,而且不受混合物中农药组分浓度的影响。基于二维荧光相关光谱,对实际茶汤中氰戊菊酯和顺式氯氰菊酯进行了识别,识别率分别为80%和83%。     

酯基取代的吲哚衍生物的红外和荧光光谱研究（英文）

色氨酸衍生物长期以来一直被用作位点特异性的非天然氨基酸红外和荧光探针.其中,4-氰基色氨酸的荧光在可见光范围,是目前已知的最小的非天然氨基酸蓝色荧光探针.本研究组致力于发展其它小型的基于吲哚或色氨酸衍生物的蓝色、绿色和红色荧光探针.本文利用傅立叶红外光谱、紫外可见吸收光谱、稳态和时间分辨荧光光谱系统测量了酯基取代的六种吲哚衍生物在不同溶剂中的光谱.发现吲哚-4-甲酸甲酯的荧光在450 nm,并且具有较长的荧光寿命,有望被用作新型的非天然氨基酸荧光探针.本文的研究不仅为选择合适的吲哚衍生物进行实际应用提供了指导,并且为计算吲哚不同位置的取代对电子跃迁的影响提供了实验数据.     

新型BODIPY荧光染料的合成及光谱性质研究

传统的BODIPY荧光染料具有荧光量子效率高、摩尔消光系数大、紫外吸收和荧光发射峰窄等优点,然而这类荧光染料普遍存在荧光发射波长短和Stokes位移小的缺点,因而限制了它们在体内生物传感及成像方面的广泛应用。为了得到荧光发射波长较长和Stokes位移大的BODIPY荧光染料,以BODIPY母核为基本结构,通过在它的8位连接吸电子性质的酯基来增加分子内电荷转移程度,同时在其3,5位引入供电子的芳香取代基增加分子的π共轭结构,合成得到了一类8位酯基取代的新型BODIPY荧光染料。所得到的新型BODIPY荧光染料的化学结构经过1H NMR, 13C NMR和HR-MS得以确认。光谱测试结果表明,这类染料的紫外吸收光谱(λ_abs=536 nm)和荧光发射光谱(λ_em=592 nm)与普通的BODIPY相比都发生显著红移(80 nm),并且保持了较高的荧光量子效率(Ф=0.43)。此外,这类BODIPY荧光染料的紫外可见吸收光谱和荧光发射光谱几乎完全分开,Stokes位移长达60 nm,可以有效地避免自吸收和生物样品的背景干扰。密度泛函理论计算结果表明,这种相对较大的Stokes位移主要是由于染料分子在基态和激发态下不同的几何构型所造成的。该类化合物的光物理性能受溶剂的影响小,是一类性能优良的新型荧光染料。细胞成像结果表明,染料1具有良好的细胞渗透性和光稳定性,可以实现对细胞的荧光成像。     

新型BODIPY荧光染料的合成及光谱性质研究（英文）

传统的BODIPY荧光染料具有荧光量子效率高、摩尔消光系数大、紫外吸收和荧光发射峰窄等优点,然而这类荧光染料普遍存在荧光发射波长短和Stokes位移小的缺点,因而限制了它们在体内生物传感及成像方面的广泛应用。为了得到荧光发射波长较长和Stokes位移大的BODIPY荧光染料,以BODIPY母核为基本结构,通过在它的8位连接吸电子性质的酯基来增加分子内电荷转移程度,同时在其3,5位引入供电子的芳香取代基增加分子的π共轭结构,合成得到了一类8位酯基取代的新型BODIPY荧光染料。所得到的新型BODIPY荧光染料的化学结构经过1 H NMR,13 C NMR和HR-MS得以确认。光谱测试结果表明,这类染料的紫外吸收光谱(λabs=536nm)和荧光发射光谱(λem=592nm)与普通的BODIPY相比都发生显著红移(80nm),并且保持了较高的荧光量子效率(Ф=0.43)。此外,这类BODIPY荧光染料的紫外可见吸收光谱和荧光发射光谱几乎完全分开,Stokes位移长达60nm,可以有效地避免自吸收和生物样品的背景干扰。密度泛函理论计算结果表明,这种相对较大的Stokes位移主要是由于染料分子在基态和激发态下不同的几何构型所造成的。该类化合物的光物理性能受溶剂的影响小,是一类性能优良的新型荧光染料。细胞成像结果表明,染料1具有良好的细胞渗透性和光稳定性,可以实现对细胞的荧光成像。     

几种荧光素酯的自然水解和脂酶催化水解反应的研究

本文研究了荧光素的发光条件以及浓度、温度、pH对四种荧光素酯(荧光素二乙酸酯、荧光素二丙酸酯、荧光素二丁酸酯、荧光素二己酸酯)水解反应的影响,讨论了在脂酶存在下荧光素酯的分解反应机理,确定了每种荧光素酯的最佳酶反应条件.实验结果表明,脂酶对荧光素二丙酸酯(FDP)的酶反应效率最好,有应用前景.     

Molecular association processes and fluorescent characteristics of nanomarkers of the fluorescein family in solutions of bovine serum albumin

An analysis of the molecular association and fluorescent characteristics of nanomarkers of the fluorescein family, viz., fluorescein, erythrosine, eosine, and Rose Bengal, in BSA solutions was conducted. For all the markers a decreasing degree of molecular association was observed in the BSA solutions as compared with the solutions without protein. In the solutions with BSA, fluorescence quenching and red shifting of the fluorescence spectrum maximum occurred for the solutions with BAS compared with solutions without protein for the markers of the fluorescein family. The dependences of the degree of molecular association on pH differed for fluorescein and its halogen derivatives. The efficiency dependences of nanomarker binding with BSA on pH differed for fluorescein and its halogen derivatives.     

Time-Resolved Detection of Hot Electron-Induced Electrochemiluminescence of Fluorescein in Aqueous Solution

Strong electrogenerated chemiluminescence (ECL) of fluorescein is generated during cathodic pulse polarization of oxide-covered aluminum electrodes and the resulting decay of emission is so sluggish that time-resolved detection of fluorescein is feasible. The present ECL in aqueous solution is based on the tunnel emission of hot electrons into the aqueous electrolyte solution, which probably results in the generation of hydrated electrons and hydroxyl radicals acting as redox mediators. The successive one-electron redox steps with the primary radicals result in fluorescein in its lowest excited singlet state. The method allows the detection of fluorescein (or its derivatives containing usable linking groups to biomolecules) over several orders of magnitude of concentration with detection limits well below nanomolar concentration level. The detection limits can still be lowered, e.g., by addition of azide or bromide ions as coreactants. The results suggest that the derivatives of fluorescein, such as fluorescein isothiocyanate (FITC), can be detected by time-resolved measurements and thus be efficiently used as electrochemiluminescent labels in bioaffinity assays.     

Synthesis of novel fluorescently labeled water-soluble fullerenes and their application to its cellar uptake and distribution properties

Fullerene is a well-known carbon nanomaterial, which can be potentially used for drug manufacture or delivery. Despite several successful examples of utilizing fullerene derivatives as drug candidate materials, their low water solubility under physiological conditions negatively affects the cell penetration efficiency after treatment. In this work, we successfully synthesized two fullerene derivatives with covalently attached fluorescein and boron dipyrromethene (BODIPY) fluorophore moieties, which exhibited cellular uptake and intracellular localization. While both fluorophores decreased their fluorescence intensity in the vicinity of fullerene, the cellar uptake of the fluorescein-modified fullerene was detected via fluorescence microscopy observations. Moreover, decreases in the fluorescence intensities of the intact fluorescein and BODIPY species were observed when both fluorophores and fullerene coexisted in aqueous media.     

Determination of the binding constants of nanomarkers of the fluorescein family to human serum albumin

Using three models, the constant of quenching of fluorescence of nanomarkers of the fluorescein family and the actual constants of its binding to human serum albumin (HSA) at different values of pH are determined. The presence of two mechanisms of binding of nanomarkers of the fluorescein family to HSA and anti-cooperativity are shown. The dependence of the constants of the quenching fluorescence of nanomarkers on pH was found: for fluorescein this was nonlinear, for its halogen derivatives (erythsosine, eosin, and Rose Bengal) it was monotonous and decreased with an increase of pH. It is shown that the electronegativity of the atoms in the structural formulas of nanomarkers of the fluorescein family influences the values of the constants of binding of nanomarkers to HSA.     

Photophysical Processes in Molecules of Halogenated Fluorescein Derivatives in Anionic Reverse Micelles

Optics and Spectroscopy - We studied the photophysical processes of halogenated fluorescein derivatives (eosin (E), erythrosine (ER), and Rose Bengal (RB)) in aqueous micellar solutions using...     

Synthesis and Studies of Fluorescein Based Derivatives for their Optical Properties,Urease Inhibition and Molecular Docking

Herein, we design and synthesized new fluorescein based derivatives by insitu formation of fluorescein ester and further treated with corresponding hydrazide and amine to yield respective compounds i.e. FB1, FB2, FB3 and FB4. The spectral purity and characterization was done by using IR, NMR and Mass spectroscopies. The synthesized derivatives were examined for their photophysical properties by using variety of organic solvents and results were discussed in details. The structural diversity of synthesized compounds motivate us to evaluate these compounds for urease inhibition. The compound FB3 (IC₅₀?=?0.0456 μM) shows 100 fold more active against Jack bean urease than standard drug thiourea (IC₅₀?=?4.7455 μM). Other synthesized compounds showed potent activity. Free radical percentage scavenging assay further supported the capacity of compounds to urease inhibition. While, molecular docking simulations helps to examine the molecular interactions of active compounds FB1, FB2, FB3 and FB4 within the binding site of urease enzyme.     

trans-Stilbene Photochemistry Beyond 500 nm

trans-Stilbene and its derivatives have been widely investigated over the past decades in terms of both photophysics and photochemistry. This study presents an intramolecular energy transfer within a triple chromophore from an optically excited fluorescein onto an extremely low-lying trans-stilbene T₁ state. As in many stilbenes an isomerization along the triplet pathway was sufficiently effective to be monitored by a decrease in the trans- and a concomitant increase in the cis-stilbene absorption bands. Semiempirical calculations and sensitizing experiments were performed to obtain a good estimate of the S₀–T₁ energy difference, which was found to be about 142 kJ/mol. This uncommonly low value enables a long-wavelength photochemistry of trans-stilbene at exciting light wavelengths ranging from 500 nm (fluorescein) up to at least 680 nm (applying an external triplet sensitizer such as methylene blue).     

Spectroscopic investigation of binding of three fluorescent nanomarkers to bionanomolecules of human serum albumin in dependence on pH

The analysis of fluorescent characteristics and degree of molecular association of three fluorescent nanomarkers (eosin, erythrosin and fluorescein) in solutions of human serum albumin (HSA) at different pHs is made. The common features for all three nanomarkers under influence of bionanomolecules of HSA are the quenching of the fluorescence, the red shift of maximum of fluorescence and the decrease of degree of molecular association for every fixed value of pH. The differences in dependences of fluorescence and degree of molecular association on pH between fluorescein and its halogen – derivatives (eosin and erythrosin) are registered. It is established that the quenching of fluorescence by HSA is of compound statically–dynamical type. The electronegativity of lateral atoms in structural formulas of nanomarkers forms the basis of explanation of all features of experimental data in the system “fluorescent nanomarker – protein – buffer solution”.     

Structure of molecular associates of fluorescent probes in solutions of human serum albumin

Spectral-luminescent characteristics and molecular association processes in solutions of human serum albumin are analyzed at different pH values for three fluorescent probes (eosin, erythrosin, and fluorescein). Common features for all three probes in protein solutions are quenching of the fluorescence, a red shift of the fluorescence maximum, a decrease in the degree of association, and an increase in the angle between dipole moments of dye molecules in dimers. This being so, differences between fluorescein and its halogen derivatives (eosin and erythrosin) are observed in the pH dependences of fluorescence, degree of association, and the angle between dipole moments of probe molecules in dimers. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 6, pp. 782–787, November–December, 2008.