pH响应的介孔二氧化硅纳米颗粒的制备及可控释放

选择带负电荷且溶解度和分子结构对pH值非常敏感的聚丙烯酸作为封堵分子, 采用静电吸附的修饰方法, 制备了pH响应的MCM-41型介孔二氧化硅纳米颗粒. 利用高倍透射电子显微镜(TEM)、 X射线衍射(XRD)、 傅里叶变换红外光谱(FTIR)及比表面积分析等手段表征了介孔二氧化硅纳米颗粒的物理化学性质. 以联钌吡啶染料分子作为模式客体分子, 研究了pH调控下的模式客体分子在介孔二氧化硅纳米颗粒中的包裹及释放行为. 结果表明, 该介孔二氧化硅纳米颗粒对pH具有很好的响应性; 在近中性条件下, 带正电的二氧化硅纳米颗粒通过静电吸附作用吸附带负电的聚丙烯酸, 导致介孔封堵, 使包载的染料分子几乎无释放; 客体分子的释放率随着pH值的降低而升高, 当pH≤5时, 染料分子显著释放, pH=1时客体分子的释放率高达98％, 可以实现对包载客体分子的控制释放. 该pH响应的介孔二氧化硅纳米颗粒载体具有制备简便、 价格低廉和包载量大等优点, 有望应用于药物的控制释放.     

信号肽功能化二氧化硅纳米颗粒的线粒体靶向作用研究

以N-(p-Maleimidophenyl)isocyanate(PMPI)为交联剂, 将线粒体信号肽分子共价修饰到二氧化硅荧光纳米颗粒表面, 构建线粒体信号肽功能化二氧化硅荧光纳米颗粒. 采用荧光分光光度计、Zeta电位仪以及透射电子显微镜对修饰前后的二氧化硅纳米颗粒进行了表征. 结果表明, 信号肽可被成功修饰在纳米颗粒表面, 并且纳米颗粒粒径在信号肽分子修饰前后没有发生明显变化. 以分离纯化的细胞核作为对照, 采用流式细胞术考察了信号肽功能化二氧化硅荧光纳米颗粒与分离纯化后的线粒体的相互作用. 结果表明, 线粒体信号肽修饰到二氧化硅纳米颗粒表面后依然保持良好的生物活性, 能够介导二氧化硅纳米颗粒特异性识别及结合分离纯化的线粒体, 从而为线粒体监测及其功能调控研究提供了新的思路.     

基于二氧化硅荧光纳米颗粒与核酸染料SYBRGreenⅠ的双色显微成像技术用于E.coliO157:H7的检测

将免疫荧光纳米标记技术与激光共聚焦显微成像方法相结合,发展了一种基于二氧化硅荧光纳米颗粒和核酸染料SYBR Green Ⅰ的双色显微成像技术用于大肠杆菌O157:H7的检测.采用联吡啶钌(RuBpy)二氧化硅荧光纳米颗粒对羊抗大肠杆菌O157:H7抗体进行修饰,基于抗体-抗原相互作用实现了其对目标大肠杆菌O157:H7...     

基于中空介孔二氧化硅小球的pH响应性控制释放系统

空心结构的介孔二氧化硅纳米材料具有较大的比表面积和孔容积,相对于传统介孔氧化硅材料可以负载更多的药物分子,在药物缓释领域具有广阔的应用前景.本文利用改进的模板法制备了粒径与壳厚度可控的中空介孔二氧化硅纳米小球.采用透射电镜(TEM)、小角X射线散射分析(SAXS)和氮气吸附-脱附等方法对合成的中空纳米二氧化硅小球进行了表征分析,得出最佳制备工艺条件.选择优化的制备条件得到的中空介孔二氧化硅与普通介孔二氧化硅对比,将两者分别负载一定量的染料分子罗丹明B(RhB),接着在两者表面修饰溶菌酶分子作为开关分子,构筑了两个pH响应的药物控制释放系统,并对两者的装载量进行了评估,通过观察在575 nm(RhB)处荧光发射峰强度的变化来评估两者的控制释放效果在相同的时间内,空心结构的介孔二氧化硅小球释放染料分子的量要明显多于普通介孔二氧化硅小球释放染料分子的量.     

含苯并噻二唑的吩噻嗪染料分子的设计合成及其在染料敏化太阳能电池中的应用

设计合成了三种含苯并噻二唑的吩噻嗪类有机染料光敏剂JY50~JY52,在对其光物理和电化学性质进行研究的基础上,使用三种染料对纳米TiO₂电极进行敏化制备太阳能电池器件,并系统研究了其光电转化效率及电荷传输阻抗等光伏特性.研究结果表明,在染料分子中引入共轭基团有助于其摩尔吸光系数的提升,从而提升光电流.两个长烷基链的引入能够有效地抑制染料分子激发态电子在TiO₂光阳极表面的电子复合,从而提升其电子注入效率.其中,在AM 1.5（100 mW·cm^-2）的模拟光强下,基于碘电解质的染料JY51电池器件获得了7.61%的光电转化效率.     

光电化学水氧化用多孔单晶金红石TiO2纳米棒阵列光阳极的设计和构建

光电化学电池(如染料敏化太阳能电池、量子点敏化太阳能电池以及光电化学水分解电池)是实现太阳能转化及存储的有效手段之一.其中,光电极是光电化学电池的核心组成部分,它集光吸收、光生电荷输运及转移等决定光转化效率的关键过程于一身,因此构筑高活性半导体光电极以实现高效太阳能转化利用引起研究者广泛关注.多孔TiO2纳米颗粒堆垛薄膜光阳极因具有大的比表面积,可提供更多的染料(量子点)担载和反应活性位点,在光电化学电池中表现出优异活性而被广泛研究.然而, TiO2纳米颗粒间大量存在的晶界对光生电荷有较强的散射作用,降低了光生电荷的收集效率.英国牛津大学Snaith研究小组利用模板辅助水热过程首次获得了(001)晶面占优的多孔单晶锐钛矿TiO2微米颗粒,这种多孔单晶TiO2微米颗粒在具有大比表面积的同时,其单晶结构还能有效去除晶界对电荷的散射作用,因而具有优异的电荷输运特性.利用这种多孔单晶TiO2微米颗粒组建的光阳极用于染料敏化太阳能电池中,展现出优异的太阳能光电转化性能.受该工作启发,各种形貌的多孔单晶TiO2微米颗粒作为光催化剂和光电化学分解水用光阳极材料被广泛研究,并表现出优异活性.在单晶微米颗粒堆垛成的薄膜光电极中,虽然单个单晶微米颗粒中晶界对电荷的散射作用被有效抑制,但是单晶颗粒间的晶界仍然存在并影响光生电荷的收集效率.为了彻底抑制晶界对光生电荷的散射作用,每个单晶颗粒都应该贯穿整个薄膜,例如一维TiO2纳米棒单晶阵列薄膜.虽然一维单晶阵列薄膜能够有效提高光生电荷的收集效率,但相对于多孔薄膜具有较小的比表面积,限制了担载染料(量子点)和反应位点的数量.为了增大TiO2单晶纳米棒阵列薄膜的比表面积,目前主要的手段包括调控纳米棒长径比、表面修饰TiO2纳米颗粒以及二次生长构建TiO2枝晶阵列.本文首次提出通过制备多孔单晶TiO2纳米棒单晶阵列薄膜来获得高比表面积和高光生电荷收集效率的光阳极,提高光电化学电池的效率.在透明导电薄膜(FTO)表面利用水热生长TiO2纳米棒阵列薄膜之前,预先在FTO基体上沉积一层SiO2球密堆模板, TiO2纳米棒单晶阵列在从FTO表面向上生长过程中,会将SiO2球模板包裹进TiO2纳米棒中,再通过碱溶液将SiO2球模板溶解,首次在FTO基体上原位生长出多孔单晶TiO2纳米棒阵列薄膜.将所得多孔单晶金红石TiO2纳米棒阵列薄膜作为光电化学分解水电池光阳极,其光电化学分解水活性相对于实心单晶金红石TiO2纳米棒阵列提高了2.6倍.多孔单晶金红石TiO2纳米棒阵列光阳极性能的提升可归因于：(1)多孔结构赋予多孔单晶金红石TiO2纳米棒阵列薄膜更大的比表面积,可提供更多的反应活性位点;(2)多孔结构能够有效缩短单晶金红石TiO2纳米棒中光生电荷体相输运距离,提高光生电荷的收集效率;(3)多孔结构通过对光多次反射吸收可有效增强光吸收,产生更多光生电荷参与水分解反应;(4)在制备过程中引入Si掺杂,导致多孔单晶金红石TiO2纳米棒带隙扩大了0.1 eV,带隙增大归因于导带位置负移0.1 eV,光生电子具有更强的还原能力,光电流起始电位相应负移约0.1 V.     

新型FITC掺杂的二氧化硅荧光纳米粒子的合成及其应用于pH传感的研究

将异硫氰酸荧光素(FITC)与3-氨基丙基三甲氧基硅烷(APTMS)反应制得前驱体FITC-APTMS,采用油包水微乳液法,利用APTMS与正硅酸乙酯(TEOS)的共水解与聚合作用,制备了FITC掺杂的二氧化硅核壳型荧光纳米粒子。经TEM与荧光光谱表征及光稳定性实验与染料泄露实验等,表明所制得纳米颗粒呈规则球形,粒径为(150±15)nm,具有良好的单分散性与光稳定性,不易发生染料泄露。这种纳米颗粒对pH值敏感,在pH3.6～9.7范围内,荧光强度与溶液酸度有良好的响应,其中在pH6.0～9.0之间呈良好的线性关系,此纳米颗粒能被单个小鼠神经干细胞吞噬,可应用于细胞的pH值实时监测。     

光电化学水氧化用多孔单晶金红石TiO_2纳米棒阵列光阳极的设计和构建（英文）

光电化学电池(如染料敏化太阳能电池、量子点敏化太阳能电池以及光电化学水分解电池)是实现太阳能转化及存储的有效手段之一.其中,光电极是光电化学电池的核心组成部分,它集光吸收、光生电荷输运及转移等决定光转化效率的关键过程于一身,因此构筑高活性半导体光电极以实现高效太阳能转化利用引起研究者广泛关注.多孔Ti O2纳米颗粒堆垛薄膜光阳极因具有大的比表面积,可提供更多的染料(量子点)担载和反应活性位点,在光电化学电池中表现出优异活性而被广泛研究.然而,TiO 2纳米颗粒间大量存在的晶界对光生电荷有较强的散射作用,降低了光生电荷的收集效率.英国牛津大学Snaith研究小组利用模板辅助水热过程首次获得了(001)晶面占优的多孔单晶锐钛矿Ti O2微米颗粒,这种多孔单晶Ti O2微米颗粒在具有大比表面积的同时,其单晶结构还能有效去除晶界对电荷的散射作用,因而具有优异的电荷输运特性.利用这种多孔单晶Ti O2微米颗粒组建的光阳极用于染料敏化太阳能电池中,展现出优异的太阳能光电转化性能.受该工作启发,各种形貌的多孔单晶Ti O2微米颗粒作为光催化剂和光电化学分解水用光阳极材料被广泛研究,并表现出优异活性.在单晶微米颗粒堆垛成的薄膜光电极中,虽然单个单晶微米颗粒中晶界对电荷的散射作用被有效抑制,但是单晶颗粒间的晶界仍然存在并影响光生电荷的收集效率.为了彻底抑制晶界对光生电荷的散射作用,每个单晶颗粒都应该贯穿整个薄膜,例如一维Ti O2纳米棒单晶阵列薄膜.虽然一维单晶阵列薄膜能够有效提高光生电荷的收集效率,但相对于多孔薄膜具有较小的比表面积,限制了担载染料(量子点)和反应位点的数量.为了增大TiO 2单晶纳米棒阵列薄膜的比表面积,目前主要的手段包括调控纳米棒长径比、表面修饰Ti O2纳米颗粒以及二次生长构建Ti O2枝晶阵列.本文首次提出通过制备多孔单晶Ti O2纳米棒单晶阵列薄膜来获得高比表面积和高光生电荷收集效率的光阳极,提高光电化学电池的效率.在透明导电薄膜(FTO)表面利用水热生长Ti O2纳米棒阵列薄膜之前,预先在FTO基体上沉积一层Si O2球密堆模板,Ti O2纳米棒单晶阵列在从FTO表面向上生长过程中,会将SiO 2球模板包裹进Ti O2纳米棒中,再通过碱溶液将Si O2球模板溶解,首次在FTO基体上原位生长出多孔单晶Ti O2纳米棒阵列薄膜.将所得多孔单晶金红石Ti O2纳米棒阵列薄膜作为光电化学分解水电池光阳极,其光电化学分解水活性相对于实心单晶金红石Ti O2纳米棒阵列提高了2.6倍.多孔单晶金红石Ti O2纳米棒阵列光阳极性能的提升可归因于:(1)多孔结构赋予多孔单晶金红石Ti O2纳米棒阵列薄膜更大的比表面积,可提供更多的反应活性位点;(2)多孔结构能够有效缩短单晶金红石Ti O2纳米棒中光生电荷体相输运距离,提高光生电荷的收集效率;(3)多孔结构通过对光多次反射吸收可有效增强光吸收,产生更多光生电荷参与水分解反应;(4)在制备过程中引入Si掺杂,导致多孔单晶金红石Ti O2纳米棒带隙扩大了0.1 e V,带隙增大归因于导带位置负移0.1 e V,光生电子具有更强的还原能力,光电流起始电位相应负移约0.1 V.     

内嵌硫化镉与上转换纳米颗粒的二氧化钛复合纳米管用于近红外光驱动光催化

由于近红外光在太阳光谱中占44%,因此,近红外光驱动的光催化剂的研制具有十分重要的意义.上转换发光材料可将低能量的近红外光子转换为高能光子,这种高能光子可以通过构建荧光共振转移系统将能量转移并活化量子效率较高的半导体材料,对于太阳能的转化利用具有潜在的应用前景.在本文中,通过胶体化学的过程在电纺丝制备的内嵌CdS纳米颗粒以及上转换荧光纳米颗粒(UCNPs)的二氧化硅复合纳米纤维表面外延生长一层二氧化钛层,通过高温煅烧得到二氧化钛复合纳米管.我们通过二氧化硅结构将CdS纳米颗粒与上转换荧光纳米颗粒紧紧束缚在一起,实现较高的荧光共振能量转移.而且,选择β-NaYF4:Yb(30%),Tm(0.5%)@NaYF4:Yb(20%),Er(2%)作为纳米能量转换器,替代以前研究工作中使用的β-NaYF4:Yb(30%),Tm(0.5%)或者β-NaYF4:Yb(30%),Tm(0.5%)@NaYF4纳米颗粒,来进一步提高近红外光的转换效率.通过透射电子显微镜照片很清楚的观察到制备的TiO2复合纳米管内部内嵌有大量的CdS与上转换纳米颗粒.通过X-射线衍射以及X-射线光电子能谱能仪器对产物的物相以及表面的化学组成进行了细致的表征.结果显示,通过本实验方法已经成功获得了TiO2复合纳米管.用稳态与瞬态荧光仪研究了最终样品的荧光性质.研究结果揭示,与上转换纳米颗粒以及二氧化硅复合纳米纤维相比,复合二氧化钛纳米管可以将上转换荧光纳米颗粒的(UV-Vis)部分荧光完全淬灭了.特别是,铒离子的荧光(650 nm)也被有效淬灭转移,说明本研究采用β-NaYF4:Yb(30%),Tm(0.5%)@NaYF4:Yb(20%),Er(2%)纳米能量转换器,可以提高近红外光的转换效率,紫外-可见吸收光谱证实,这种二氧化钛纳米管在紫外-可见光区中的吸收光谱与β-NaYF4:Yb(30%),Tm(0.5%)@NaYF4:Yb(20%),Er(2%)纳米颗粒的荧光光谱具有较大的重叠,使得上转换荧光纳米颗粒与CdS以及二氧化钛组分之间的荧光共振转移的效率大大提高,进而会显著提高光催化的效果.以罗丹明染料作为污染物为模型,我们研究了罗丹明染料在氙灯下或者近红外光光照下的光催化分解实验.研究结果表明,90%的罗丹明染料分子在20 min内就被降解掉,效率高于其它的近红外光催化剂.上转换荧光纳米颗粒的能量转换效率可以得到大幅度提高,本研究工作中制备的光催化剂利用太阳能的效率将会得到极大提高,在未来为能源危机以及环境保护提供一种可供选择的方法与技术.     

纳米SiO_2颗粒表面修饰的有机分子在介质中的光物理行为研究

利用Sol-Gel方法投篮了单分散性很好的球型二氧化硅纳米颗粒，通过表面化 学修饰法引入了带有荧光发色团的有机分子，通过稳态光物理方法研究了纳米颗粒 表面的有机分子在水、乙醇以及阴、阳离子表面活性剂悬浮液中的光物理行为。实 验表明，纳米颗粒表面有机分子的分散状态是决定其光物理行为的主要因素。这一 结果为设计和开发新型“壳-核”型纳米二氧化硅荧光传感器提供了有用的参考。     

A BODIPY-functionalized bimetallic probe for sensitive and selective color-fluorometric chemosensing of Hg(2+)

A new BODIPY dye conjugate has demonstrated selective quenching by mercury over other metal ions. Coupling of this probe to Au-Fe(3)O(4) nanoparticles as well as platinum electrodes offered sensitive systems for suspension and surface based sensing, respectively.     

Difluoro-boron-triaza-anthracene: a laser dye in the blue region. Theoretical simulation of alternative difluoro-boron-diaza-aromatic systems

The synthesis, photophysical and laser properties of a difluoro-boron-triaza-anthracene (BTAA) compound are analyzed in the present paper. The molecular structure of this dye is an anthracene-like core with N atoms at 4a, 9 and 10a positions where two of them (4a and 10a) are linked through a BF(2)-bridge group. This structure is reminiscent of aza-BODIPY dye with an s-indacene core, BODIPY being one of the most commonly used laser dye family in the Vis region. The main absorption and emission bands of the new dye are localized in the blue part of the Vis region of the electromagnetic radiation, a spectral region practically unexploited by the BODIPY chromophore. Moreover, the new dye presents a higher laser efficiency and photostability than other commercial laser dyes operating in the same spectral region. In order to look for new molecular structures with potential laser emission covering the whole Vis spectral region, the spectroscopic properties of other different chromophoric systems based on BF(2)-linking aromatic groups are theoretically simulated by quantum mechanical calculations.     

Glass-encapsulated light harvesters: more efficient dye-sensitized solar cells by deposition of self-aligned, conformal, and self-limited silica layers

A major loss mechanism in dye-sensitized solar cells (DSCs) is recombination at the TiO(2)/electrolyte interface. Here we report a method to reduce greatly this loss mechanism. We deposit insulating and transparent silica (SiO(2)) onto the open areas of a nanoparticulate TiO(2) surface while avoiding any deposition of SiO(2) over or under the organic dye molecules. The SiO(2) coating covers the highly convoluted surface of the TiO(2) conformally and with a uniform thickness throughout the thousands of layers of nanoparticles. DSCs incorporating these selective and self-aligned SiO(2) layers achieved a 36% increase in relative efficiency versus control uncoated cells.     

Ultrafast Photoinduced Electron Transfer in Viologen‐Linked BODIPY Dyes

New boron‐dipyrromethene (BODIPY) dyes linked to viologen are prepared and their photophysical and electrochemical properties are investigated. Both synthesized molecules have similar electronic absorption spectra with the absorption maximum localized at 517 and 501 nm for dye 1 and dye 2 , respectively. They exhibit well‐defined redox behavior, highlighting the presence of BODIPY and viologen subunits, with little perturbation of the redox potential of both subunits with respect to the parent compounds. Both dyes are heavily quenched by photoinduced electron transfer from the BODIPY to the viologen subunit. The transient absorption technique demonstrates that dye 2 forms the viologen radical within a timeframe of 7.1 ps, and that the charge‐separated species has a lifetime of 59 ps. Sustained irradiation of dye 2 in the presence of a tertiary amine allows for the accumulation of BODIPY–methyl‐4,4′‐bipyridinium (BODIPY–MV⁺), as observed by its characteristic absorption at 396 and 603 nm. However, dye 2 does not generate catalytic amounts of hydrogen under standard conditions.     

Preparation and electrochemical properties of core-shell Si/SiO nanocomposite as anode material for lithium ion batteries

The Si/SiO nanocomposite was synthesized by a sol–gel method in combination with a following heat-treatment process. It was analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), cyclic voltammetry (CV) and capacity measurement as anode material for lithium ion battery. Si nanoparticles were coated with SiO and a core-shell structured nanocomposite was formed. The core-shell Si/SiO nanocomposite displays better reversibility of lithium insertion/extraction and higher coulomb efficiency than virginal Si nanoparticles. The SiO shell envelops the Si nanoparticles to suppress the aggregation of the nanoparticles during cycling. As a result, the core-shell Si/SiO nanocomposite exhibits better capacity retention than virginal Si nanoparticles, indicating that this is a promising approach to improve the electrochemical performance of nano anode materials for lithium ion battery.     

Synthesis and Characterization of Far‐Red/NIR‐Fluorescent BODIPY Dyes,Solid‐State Fluorescence,and Application as Fluorescent Tags Attached to Carbon Nano‐onions

A series of π‐extended distyryl‐substituted boron dipyrromethene (BODIPY) derivatives with intense far‐red/near‐infrared (NIR) fluorescence was synthesized and characterized, with a view to enhance the dye’s performance for fluorescence labeling. An enhanced brightness was achieved by the introduction of two methyl substituents in the meso positions on the phenyl group of the BODIPY molecule; these substituents resulted in increased structural rigidity. Solid‐state fluorescence was observed for one of the distyryl‐substituted BODIPY derivatives. The introduction of a terminal bromo substituent allows for the subsequent immobilization of the BODIPY fluorophore on the surface of carbon nano‐onions (CNOs), which leads to potential imaging agents for biological and biomedical applications. The far‐red/NIR‐fluorescent CNO nanoparticles were characterized by absorption, fluorescence, and Raman spectroscopies, as well as by thermogravimetric analysis, dynamic light scattering, high‐resolution transmission electron microscopy, and confocal microscopy.     

SiO2/graphene composite for highly selective adsorption of Pb(II) ion

SiO(2)/graphene composite was prepared through a simple two-step reaction, including the preparation of SiO(2)/graphene oxide and the reduction of graphene oxide (GO). The composite was characterized by UV-Vis spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscope, and X-ray photoelectron spectroscopy, and what is more, the adsorption behavior of as-synthesized SiO(2)/graphene composite was investigated. It was interestingly found that the composite shows high efficiency and high selectivity toward Pb(II) ion. The maximum adsorption capacity of SiO(2)/graphene composite for Pb(II) ion was found to be 113.6 mg g(-1), which was much higher than that of bare SiO(2) nanoparticles. The results indicated that SiO(2)/graphene composite with high adsorption efficiency and fast adsorption equilibrium can be used as a practical adsorbent for Pb(II) ion.     

Human Serum Albumin Labelling with a New BODIPY Dye Having a Large Stokes Shift

BODIPY dyes are photostable neutral derivatives of 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene. These are widely used as chemosensors, laser materials, and molecular probes. At the same time, BODIPY dyes have small or moderate Stokes shifts like most other fluorophores. Large Stokes shifts are preferred for fluorophores because of higher sensitivity of such probes and sensors. The new boron containing BODIPY dye was designed and synthesized. We succeeded to perform an annulation of pyrrole ring with coumarin heterocyclic system and achieved a remarkable difference in absorption and emission maximum of obtained fluorophore up to 100 nm. This BODIPY dye was equipped with linker arm and was functionalized with a maleimide residue specifically reactive towards thiol groups of proteins. BODIPY residue equipped with a suitable targeting protein core can be used as a suitable imaging probe and agent for Boron Neutron Capture Therapy (BNCT). As the most abundant protein with a variety of physiological functions, human serum albumin (HSA) has been used extensively for the delivery and improvement of therapeutic molecules. Thiolactone chemistry provides a powerful tool to prepare albumin-based multimodal constructions. The released sulfhydryl groups of the homocysteine functional handle in thiolactone modified HSA were labeled with BODIPY dye to prepare a labeled albumin-BODIPY dye conjugate confirmed by MALDI-TOF-MS, UV-vis, and fluorescent emission spectra. Cytotoxicity of the resulting conjugate was investigated. This study is the basis for a novel BODIPY dye-albumin theranostic for BNCT. The results provide further impetus to develop derivatives of HSA for delivery of boron to cancer cells.     

Preparation of an IMI dye (imidazole functional group) containing a 4-(N,N-dimethylaminosulfonyl)-2,1,3-benzoxadiazole fluorophore for labeling of phosphomonoesters

We are studying dye-imidazole conjugates ("IMI dyes") as reagents for labeling phosphomonoesters such as nucleotides. Previously we have employed a BODIPY dye in our IMI reagents, and analyzed the labeled products by capillary electrophoresis with laser-induced fluorescence detection (CE-LIF) involving an argon ion laser. (The BODIPY fluorophore is a 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene). Here we broaden the technology by preparing a DBD-IMI dye [DBD = 4-(N,N-dimethylaminosulfonyl)-2,1,3-benzoxadiazole], and using a helium-cadmium laser. While DBD-IMI (IMI3) is about 50x more stable photolytically than a BODIPY-IMI dye (IMI2, a conjugate of a BODIPY dye with histamine, was tested), the detection limit for IMI2 (5.10(-11) M; S/N = 5, CE-LIF with an argon ion laser) is tenfold better than that for IMI3 (5.10(-10) M, S/N = 5, helium-cadmium laser). IMI3 conjugates of the four major DNA nucleotides were prepared and detected by CE-LIF.