竹红菌乙素对模拟生物膜-脂质体环境变化的荧光响应

脂质体不但可以作为药物传输体系, 而且还作为一种模拟生物膜的简单模型. 近期报道竹红菌素的荧光性质决定于其分子内质子转移, 而分子内质子转移环境敏感特性决定其分子的环境敏感荧光性质. 文中以脂质体为模拟生物膜研究竹红菌乙素(HB)在膜上微环境敏感的荧光性质, 包括生理范围pH值变动(6.0~8.0)、胆固醇浓度和离子强度的变化对竹红菌素荧光的影响. 发现HB的荧光强度对微环境敏感且可被调控. 保持磷酸缓冲液(PBS)中胆固醇和离子强度的浓度不变, 发现脂质体中HB的荧光强度在pH7.4时有一极大值而在缓冲溶液中pH7.0时HB的荧光强度有一极小值. 保持pH值7.2不变, HB脂质体的荧光强度分别在离子强度为0.12 mol/kg和胆固醇浓度为6 × 10^-4mol/L达到峰值. 对于HB的PBS溶液来说, 它的荧光强度与离子强度成反比. 这种环境敏感的荧光特性可能用于探测生物组织或生物大分子微环境特征.     

化学敏感半导体器件

近几年来,由于电化学家和固体物理学家的结合,电化学与半导体技术和理论的相互渗透,提出了一类能够敏感离子或分子的半导体器件,称为化学敏感半导体器件。这类器件的出现不仅影响着电分析化学、医学和生物学等学科,而且对固体物理学的研究也具有重要意义。随着近十多年来离子选择性电极(或称化学敏感选择性电极)技术的发展,Bergveld首先提出了一个化学敏感半导体器件,他称之为离子敏感场效应管(Ion Sensistive Field Effect Transistor,简称ISFET)。Bergveld用普通的金属-氧化物-半导体场效应管(MOSFET),     

不同种类敏感膜修饰的QCM气体传感器研究现状

石英晶体微天平(quartz crystal microbalance,QCM)是一种对质量变化敏感的器件,具有灵敏度高、成本低廉、操作简单、可实时在线检测等优点,在气体传感领域受到了广泛关注。敏感材料是石英晶体微天平气体传感器的关键组成部分,本文综述了不同敏感材料包括有机聚合物、超分子化合物、离子液体和分子液体以及近年来备受关注的纳米材料修饰的QCM对特定气体传感检测的研究现状,详细介绍了纳米材料为敏感膜的QCM气体传感器对不同气体传感检测的研究现状及相关敏感机理。最后,在国内外研究现状的基础上,展望了敏感材料的发展前景。QCM作为一种成本低廉、操作方便、测量精度高的气体传感检测器件,将会有更加广阔的应用前景。     

大黄酸ESI-IT MS质谱行为及碎片离子的量子化学研究

采用电喷雾-离子阱质谱(ESI-IT MS),获取大黄酸分子的一级质谱和多级质谱碰撞诱导解离下的碎片离子,以量子化学计算大黄酸分子及其主要碎片离子的质谱行为。通过对质谱离子几何参数、键断裂能、电荷变化、自旋密度以及前线分子轨道的分析,可得到m/z 282.8、256.9、238.9、210.8、192.8、182.8、166.8离子的稳定构型以及质谱裂解途径,从而较系统地解释了大黄酸分子在ESI-IT MS中的裂解行为。     

聚丙烯酸环境响应行为的研究

采用介观动力学分子模拟(Mesodyn)和耗散颗粒动力学(DPD)分子模拟与流变等实验技术相结合的方法, 研究了pH/无机盐敏感聚合物聚丙烯酸PAA在水溶液中的环境响应行为, 考察了聚合物浓度、溶液离子强度、聚合物表面电荷对PAA相行为的影响. 实验结论与模拟结果符合得很好, 对照分析给出了聚丙烯酸的环境响应机制, 为设计和应用环境敏感的智能体系提供指导和理论依据.     

一种用于识别肌酸酐分子的荧光化学敏感器

合成了一种对肌酸酐分子有选择识别能力的敏感器,它可通过氢键相互作用而 和肌酸酐分子相络合,并在络合的同时引起敏感器荧光强度的增大以达到识别的指 示作用。对几种可能产生干扰作用的化物如脲素、氨基酸是否对该敏感器分子的工 作有所干扰进行了试验,表明所合成的敏感器分子对肌酸酐分子有着专一的识别能 力。     

介绍一种判断小分子(或离子)中心原子杂化轨道类型的方法

本文针对《无机化学》课程的学习难点,以大学一年级学生已掌握的化合价和原子结构的基础知识为基础,提出一种判断小分子或离子杂化轨道类型、π键的数目和类型的方法。该法亦适用于σ配体所形成的配合物、多中心原子的分子或离子以及双原子分子,并可用于计算MAx型分子或离子的键级。     

新型荧光化学敏感器的合成及性质研究

分子识别是超分子化学的一个重要方面.它是分子传递和酶催化的基础.以分子识别为基础,设计和合成了有光谱响应的荧光化学敏感器和离子显色试剂,在生物化学、临床医学、环境科学等与人类生命科学密切相关的领域中有着很强的应用背景.本论文系统总结了环糊精对有机分子的包结特征和包结作用对客体分子光物理性质的影响,以及用荧光发色团化学修饰的环糊精分子在识别研究中的发展状况.考虑到当前分子识别研究中的另一问题,即发展对阴离子物种有选择性响应的荧光化学敏感器和显色试剂,本论文还总结了目前在设计和合成阴离子接受体方面的发展状况和特点.本论文工作正是从以下两个方面进行了研究.     

智能聚合物的双水相体系在生物分子分离纯化中的应用*

简单地改变智能聚合物组成的双水相体系的外界条件,如温度、酸度、离子强度、光照强度、电场、磁场强度等,就可使成相聚合物与生物分子分离。基于智能聚合物的双水相体系分离过程简单,聚合物材料易于回收。近年来,以智能聚合物组成的双水相体系在分离纯化生物分子的研究中发展迅速。本文简要介绍了双水相萃取的原理,综述了十多年来温度敏感型、酸度敏感型、光敏型和具有亲和功能的双水相体系和双水相萃取与其他相关技术的结合在生物分子分离纯化中的研究进展。     

氟硼二吡咯亚甲基类荧光探针在离子检测中的应用进展

氟硼二吡咯亚甲基类(BODIPY)类化合物具有摩尔吸光系数高、荧光量子产率高、吸收波长在可见光或近红外区域、荧光寿命长和光稳定性好等特点,并且其荧光对溶剂的极性和pH均不敏感,是一类可应用于生物领域的荧光染料,近年来,此类化合物被广泛用于设计合成荧光传感器分子,用于各种离子的检测,此类荧光探针具有分析灵敏度高、选择性好等特点.综述了氟硼二吡咯亚甲基类荧光探针在离子识别和检测中的应用,并展望了该领域的前景.     

含杯芳烃聚合物的合成与应用

杯芳烃在主客体化学中是继冠醚和环糊精之后被广泛关注的第三代主体分子,能够选择性地与客体分子或离子形成络合物。近年来,含杯芳烃聚合物逐渐受到人们的重视。结合聚合物稳定性好,易于加工的特性,含杯芳烃聚合物将有望被开发成为新型功能高分子材料。本文详细介绍了含杯芳烃聚合物的合成及其应用。     

Electrochemistry of Calixarene and its Analytical Applications

The electrochemistry of calixarene as a redox-dependent ionophore and its structural dependence are described. One or more redox-centers such as quinone, ferrocene, cobaltocenium and ruthenium bipyridine moieties have been introduced into the calixarene frame of the lower or upper rim. Although the electrochemical behavior depends mainly on the inherent redox property of these electrochemically active groups, the structural effect and solvent also play important roles, especially, in the presence of charged guests. When cationic species such as metal ions and ammonium ion are added to a quinone-functionalized calixarene solution, electron transfer to quinone is enhanced by the electrostatic effect or the formation of hydrogen bonds. In addition to redox-active hosts for voltammetric use, a number of calixarenes with novel structures have been developed as ionophores for potentiometric analysis and found to be successful for some target ions. In terms of Na+, Cs+ and Ca2+ selective ionophores for ion-selective electrodes, calixarenes are found to be excellent compared to crown ether derivatives or cryptands. Calixarenes can be also utilized to construct chemically modified electrodes, which are sensitive to gas species and biologically important compounds. The sophisticated design and synthesis of calixarenes are essential to specific potential applications to diverse fields.     

Polypyrrole Nanoparticles Based Disposable Potentiometric Sensors

In this work polypyrrole nanoparticles of high electrochemical activity were used to prepare disposable, potentiometric sensors with a paper support. The paper support modified with polypyrrole nanoparticles served as electrical lead and ion‐to‐electron transducer and it was covered by a typical poly(vinyl chloride) based ion‐selective membrane. The properties of this arrangement were tested on example of potassium‐selective electrodes. The sensors prepared benefited from the properties of conducting polymer nanostructures: high electrical conductivity and electroactivity as well as absence of suspension stabilizing agent. The obtained electrodes were characterized with analytical parameters well comparable with those of classical ion‐selective electrodes.     

类金刚石薄膜修饰传感器在电化学中的应用

综述了类金刚石薄膜及其修饰的传感器特性以及制备工艺,介绍了类金刚石薄膜修饰的传感器在生物检测、电化学微重力测量、痕量金属检测、氢离子选择场效应晶体管和气体检测等领域的应用,并对类金刚石薄膜修饰传感器在电化学相关领域的应用进行了展望。     

Sensing parts per million levels of gaseous NO2 by a optical fiber transducer based on calix[4]arenes

Calixarenes are interesting building blocks in supramolecular receptor design. They can be easily functionalized to give the desired guest binding and sequestration properties. We demonstrate here the use of simple alkylated calixarenes as novel NO₂ sensors. Upon reacting with gaseous NO₂, alkylated calixarenes form stable calixarene-NO⁺ (nitrosonium) complexes that have a deep purple color. This specific and selective formation of the colored complex was used to develop a fiber optic based colorimetric NO₂ sensor. Several alkylated calixarenes are used and tested as sensing materials. The calixarene compound was immobilized on a fine mesh silica-gel coated thin layer chromatography plate. The sensing plate was coupled with a fiber optic based photodetector. Gas samples were sampled in a manner where they impinged on the surface of sensing plate. The light transmission through the plate was continuously monitored. For a 5 min sample, the limit of detection was 0.54 ppmv with 1,3-alternate O-hexyl calix[4]arene (1a). There were no significant response differences between different conformations of calixarenes such as 1,3-alternate or cone. This chemistry can form the basis of a colorimetric sensor that relies on extant filter tape technology.With calixarenes however, such a reaction is potentially reversible - color formed upon reaction with NO₂ can be reversed by flushing the sensing plate by purified air. While we found that the removal of the developed color can be accelerated by simultaneous heating and suction, permitting the reuse of the same sensing area multiple times, we also observed that the sensitivity gradually decreased. The nitrosonium calixarene derivative tends to transform to the nitrated form; this process is catalyzed by light. Several methylated calixarenes were synthesized and tested but a fully satisfactory solution has proven elusive.     

Selective sensing and transport in bionic nanochannel based on macrocyclic host-guest chemistry

Imitating the signal transduction and transmembrane transport co ntrolled by biological channels in the cell membra ne,artificial nanochannels with a similar capability of sensing and transport are constructed as bionic nanochannels.To accomplish selective sensing and transport of biological analyte(as "guest"),the bionic nanochannels are modified with the artificial receptor(as "host"),Based on selective recognition between host and guest,bionic nanochannels translate the stimulus of the guest to electrochemical signal as sensors,and further regulate the transmission of guest as transporters.Howeve r,throughout all kinds of guests,the selective sensing and transpo rt of ions and chiral molecules is a challenging problem.And throughout all hosts of ions and chiral molecules,the macrocyclic hosts with multisite of recognition show better selectivity,such as crown ethers,cyclodextrins,calixarenes,and pillararenes.In this article,we highlight recent advances in the macrocyclic host-based nanochannels for the selective sensing and transport of ionic and chiral guests,summarize the similarities and differences of different kinds of macrocyclic host-based nanochannels,and expect the research direction and application prospect.     

糖基修饰大环化合物的研究进展

糖类分子作为生命过程中多种特殊受体的底物,在生物信息传递中发挥着重要的作用.近年来,已通过各种方法高效率地制备了一些新型的糖基修饰的杯芳烃、环糊精和冠醚等大环分子,它们在生物凝集素特异性识别、选择性离子识别及手性催化等方面的应用引起了研究者的广泛兴趣.本文从糖基修饰大环分子的合成、功能化及其相关应用方面综述了目前糖基功...     

Calixarenes in analytical and separation chemistry

Discovered in the 1940’s, [1_n]metacyclophanes with the common name calix[n]arenes which is derived from for the molecule’s shape enjoyed a remarkable interest in almost all fields of chemistry since the 1980’s, which is highlighted by several books [1–8]. Over 50 reviews concerning their synthesis, properties and applicabilities were published, many of those with emphasis on organic synthesis and structural properties are cited in ¶[P. 5–6 in 2]. Of interest for analytical chemists are reviews on calixarenes and the structurally related resorcin[n]arenes (or calix[n]resorcarenes) and calixpyrroles concerning potentiometric sensors [9–12], chromo- and fluorophores [13, 14], molecular switches [15], metal ion binding in solution [16–19], redox properties [20] and anion binding [21–24]. Other recent reviews deal with thermodynamic aspects [25], organometallic compounds [26], P-containing calixarenes [27–29], as well as molecular dynamics modeling [30–33]. It is a vital field with over 200 publications per year. Therefore, this article presents only selected results on complexation, solvent extraction and membrane transport with the emphasis on ion and molecular recognition which can be used for analytical purposes, without attempting to cover all available references.     

Calixarene-based sensing agents

The well-known selective receptor properties and ease of structural modification makes calixarene derivatives attractive materials for use in chemical sensors. This review looks at the history of sensor-related calixarene research prior to 1994 and identifies current trends in sensor research which are influencing the types of derivatives being synthesised and methods of evaluation, such as the increasing popularity of optical modes of transducing host-guest interaction. Future possibilities are briefly discussed and the need for more fundamental studies highlighted.This paper is dedicated to the commemorative issue on the 50th anniversary of calixarenes.     

Calixarenes in analytical and separation chemistry

Discovered in the 1940's, [1n]metacyclophanes with the common name calix[n]arenes which is derived from for the molecule's shape enjoyed a remarkable interest in almost all fields of chemistry since the 1980's, which is highlighted by several books [1-8]. Over 50 reviews concerning their synthesis, properties and applicabilities were published, many of those with emphasis on organic synthesis and structural properties are cited in [P. 5-6 in 2]. Of interest for analytical chemists are reviews on calixarenes and the structurally related resorcin[n]arenes (or calix[n]resorcarenes) and calixpyrroles concerning potentiometric sensors [9-12], chromo- and fluorophores [13, 14], molecular switches [15], metal ion binding in solution [16-19], redox properties [20] and anion binding [21-24]. Other recent reviews deal with thermodynamic aspects [25], organometallic compounds [26], P-containing calixarenes [27-29], as well as molecular dynamics modeling [30-33]. It is a vital field with over 200 publications per year. Therefore, this article presents only selected results on complexation, solvent extraction and membrane transport with the emphasis on ion and molecular recognition which can be used for analytical purposes, without attempting to cover all available references.