基于分子印迹技术的电化学发光分析

基于分子印迹技术的电化学发光分析是近几年刚刚发展起来的新型分析方法,兼具分子印迹技术与电化学发光方法两者的优点,具有高灵敏度、高选择性、可控性好、易于微型化和操作简单等特点,在生命科学、食品安全及环境监测等领域有着广泛的应用前景。本综述简要介绍了常用的电化学发光体系和基本原理,综述了近年来分子印迹电化学发光分析的主要研究进展,对不同类型分子印迹电化学分析的构建方法、原理及所构建方法的性能（包括灵敏度、选择性、检测范围和稳定性等）进行了评述。基于分子印迹技术的电化学发光分析主要可以分为三类：制备固态发光电极、非固态发光电极构建分子印迹电化学发光传感器和分子印迹固相萃取与电化学发光分析联用,其中制备固态发光电极用于构建分子印迹电化学发光传感器最有发展前景。最后,本综述也对分子印迹电化学发光分析今后的发展趋势和方向进行了展望。     

两极隔离式双极电极的电化学发光行为及其分析特性研究

设计了一种两极隔离式双极电极电化学发光装置,并以此装置为基础,研究了电化学发光试剂鲁米诺在此装置中的电化学发光行为和分析特性。通过外加电场的诱导,可以在双极电极的两极富集、分离对应的阴、阳离子,使鲁米诺阴离子富集于双极电极的阳极端,待检测的阳离子富集于双极电极阴极端。根据鲁米诺在阳极端的电化学发光信号定量分析阴极端所富集的阳离子的总量。在最佳条件下,鲁米诺电化学发光信号与分析物浓度在1.0×10-9~1.0×10-8mol/L范围内呈线性关系,检出限达1.1×10-10mol/L。以此为基础,发展了一种电化学发光方法测定溶液电导的新方法。     

固定化联吡啶钌电化学发光免疫分析研究进展

综述了固定化联吡啶钌[Ru(bpy)23+]电化学发光免疫传感技术的发展状况,介绍了近年来在电化学发光免疫传感领域出现的新型固相载体材料和固定方法,及其与其他分析技术联用方面的发展,并对其发展趋势进行了展望.指出电化学发光免疫分析技术在生物分子检测、药物分析及临床诊断中显示出强大的生命力.Ru(bpy)23+的电化学发光已引起广泛的关注.固定化Ru(bpy)23+电化学发光免疫分析体系具有线性范围宽、灵敏度高、装置简单、可控性强等优点,被广泛应用于分子生物学、化学、药学等领域.     

分子印迹-电化学发光技术研究进展

分子印迹-电化学发光技术具有分子印迹技术的高选择性及电化学发光技术的高灵敏性,以及发光易于调控、稳定性好、便于微型化和仪器操作简单等优点,已被广泛地应用于重金属检测、免疫传感技术、基因传感技术、酶传感技术、食品安全与药物分析等领域。该文结合本实验室的研究工作介绍了分子印迹电化学发光传感器的原理和构建思路。在此基础上,着重介绍了分子印迹电化学发光技术在食品安全与药物分析中的应用,并对其今后的研究趋势进行了展望。     

压致变色聚集诱导发光材料

聚集诱导发光化合物分子具有特殊的螺旋桨形扭曲构象结构, 导致其很难在结晶状态下进行紧密堆砌, 使得其结晶结构容易在外力的作用发生改变, 致使其分子能级水平和发光光谱发生变化, 产生压致发光变色现象. 因此, 聚集诱导发光化合物是压致发光变色材料的一个重要来源. 压致变色聚集诱导发光材料是一类重要的压致发光变色材料, 其既具有压致发光变色的性能, 又具有聚集诱导发光的性能. 它是一类智能材料, 在应力传感、商标防伪和发光器件等领域具有重要的潜在应用, 近年来受到人们极大的关注. 本文分类介绍了近年来压致变色聚集诱导发光材料的研究进展.     

二苯乙烯基蒽衍生物:聚集诱导发光性质、机理及应用

与传统的发光分子相比,具有聚集诱导发光(AIE)性质的分子,在聚集态或固态条件下,由于独特的分子结构和聚集态结构,表现出显著增强的荧光发射,因而在光电器件、生物化学检测等领域展现出广阔的应用前景。本文总结了二苯乙烯基蒽(DSA)及其衍生物的AIE性质,分析了DSA类分子AIE现象的机理,如分子内转动受限、扭曲的分子结构及分子间聚集结构等,同时介绍了此类分子在固态发光、刺激-响应材料,以及生物检测和生物成像等方面的应用。     

分子印迹电化学发光分析

分子印迹电化学发光兼具分子印迹技术及电化学发光方法两者的优点,即高灵敏度、高选择性、可控性好、易于微型化和操作简单等特点。近几年来在生物仿生传感器、有害农药残留物质及食品安全监测等方面具有广泛的应用。本综述简要介绍分子印迹电化学发光传感器及分子印迹固相萃取电化学发光的概况,并对其今后的研究趋势进行展望。     

聚集诱导发光体系:化合物种类、发光机制及其应用

聚集诱导发光(AIE)体系是近年来备受关注的一个研究领域,目前该领域已经积累了较为丰富的AIE化合物的分子设计理念和相应的对AIE机制的理解。AIE体系的研究为固态强发光材料特别是备受聚集发光猝灭难题困扰的有机电致发光材料提供了全新的分子设计思路。本文纵观该领域的研究进展,对AIE化合物种类、发光机制及其相关应用做出了较为详尽的综述报道。具有AIE性质的化合物主要包括多芳基取代的杂环化合物、多芳基乙烯类化合物、分子内电荷转移化合物、含有氢键的化合物、聚合物等。这些化合物的AIE发光机制也各有不同,包括分子内旋转受限、非辐射失活衰减受限、分子构象扭曲以避免形成激基缔合物以及利用特殊的分子堆积方式如J-聚集、交叉分子堆积、由分子间的C—H…π作用或特殊的氢键作用形成相应的发光聚集体等。基于其特殊的AIE性能,AIE化合物可广泛应用于化学传感、生物传感、生物标记、电致发光以及逻辑门器件等领域。     

基于环糊精构筑的镧系稀土发光超分子组装体

镧系元素由于其优异的发光特性,如长寿命的激发态、尖锐的线状发射带和较大的Stokes位移等,在发光材料中表现出极大的优势,被越来越多地应用于高级功能发光材料的设计中.而环糊精作为第二代超分子主体分子具有易于功能化修饰以及特异性结合发光客体等优势而被广泛地用于构筑发光材料、荧光传感等超分子体系.作者从基于环糊精的镧系稀土配位化合物超分子组装体的构筑出发,对不同镧系环糊精发光材料的最新研究进展进行综述,为开发构筑新型多功能化镧系发光材料提供参考.最后,提出了稀土发光材料目前所遇到的科学问题,并对基于环糊精稀土发光材料的发展方向进行了展望.     

推拉电子结构手性四配位硼的光学性质

圆偏振发光(Circularly polarized luminescence,CPL)有机分子是一类重要的手性光学材料,在有机光学和有机电子学等领域受到广泛关注。通过引入手性联萘基团和构建推拉电子结构的设计理念同时实施到双硼氮桥联联吡啶单元,发展出了一系列具有推拉电子结构的手性四配位硼分子。结果表明,改变给电子单元可以调节分子的发光现象,含有二苯胺(2a)和咔唑(2b)单元的分子展现出典型的聚集诱导荧光淬灭现象,而含有9,9-二甲基-9,10-二氢吖啶(2c)单元的分子具有特征的聚集诱导发光性质。手性联萘基团的引入使3个分子具有手性光学性质,展现出圆二色信号和圆偏振发光特性,它们的不对称因子均超过了1×10^-3,另外,改变给电子单元有效调节了手性分子的发光颜色。     

Effect of flow development region and fringing magnetic force field on annular split-flow thin fractionation

Split-flow thin (SPLITT) fractionation devices have been widely used to separate macromolecules, colloids, cells and particles. Recently, the quadrupole magnetic flow sorter (QMS) has been reported in the literature as another family of SPLITT fractionation device. However, the separation performance observed in the experimental measurements is generally found to deviate from the ideal behaviour. Possible causes such as hydrodynamic lift force, high particle concentration and imperfect geometries have been extensively examined. However, the effects of flow development regions and fringing magnetic force field at the separation channel inlet and outlet, which are ignored by the theory, have not been investigated. The error introduced by ignoring these effects need to be rigorously studied so that the theory can be used to optimise operation flow rates with confidence. Indeed, we find in this paper that these ignored effects are responsible to the discrepancy between the experimental data and the theoretical predictions. A new theory has been proposed for optimisation of device operation.     

On-demand controlled release of docetaxel from a battery-less MEMS drug delivery device

We report the development of a magnetically controlled MEMS device capable of on-demand release of defined quantities of an antiproliferative drug, docetaxel (DTX). Controlled release of DTX with a dosage suitable for the treatment of diabetic retinopathy has been achieved for 35 days. The device consists of a drug-loaded microreservoir (?6 mm ×～550 μm), sealed by an elastic magnetic PDMS (polydimethylsiloxane) membrane (?6 mm × 40 μm) with a laser-drilled aperture (～100 × 100 μm(2)). By applying a magnetic field, the magnetic PDMS membrane deforms, causing the discharge of the drug solution from the device. Controlled DTX release at a rate of 171 ± 16.7 ng per actuation interval has been achieved for 35 days using a 255 mT magnetic field. The background leakage of drug solution through the aperture was negligible at 0.053 ± 0.014 ng min(-1). The biological activity of the released drug was investigated using a cytotoxicity assay (cell apoptosis) for two cell lines, HUVEC (human umbilical vein endothelial cells) and PC3 (prostate cancer) cells. Reproducible release rates have been achieved and DTX within the PDMS MEMS reservoir maintains full pharmacological efficacy for more than two months. This device is a proof-of-concept development for targeted delivery of hydrophobic drugs such as DTX and other taxane-based agents that require accurate delivery in nanomolar concentrations.     

Dynamic response of a unijunction transistor in the presence of a magnetic field

The influence of a magnetic field on the small-signal dynamic response of a unijunction transistor (UJT) and the performance of a UJT sine-wave oscillator in the presence of an externally applied magnetic field are discussed. A theoretical analysis of the magnetically-induced changes in differential negative resistance and inductance (which describe the dynamic response of a UJT) is proposed for low frequencies. The change in differential negative resistance and inductance due to a magnetic field has been attributed to the corresponding change in basic electrophysical parameters (carrier mobility and carrier lifetime) of the device under investigation. This theoretical analysis has been experimentally verified. Subsequently, these results have been used in a study of magnetically-induced changes in the amplitude and frequency of a UJT sine-wave oscillator. This study suggests its possible application as a magnetic transducer.     

Printable Magnetoelectronics

The field of printable electronics is well developed. A large variety of electronic components assembled as printable optoelectronic devices and communication modules are already available. However, the element responding to a magnetic field, which is highly demanded for the concept of printable electronics has only been realized very recently. A printable magnetic sensing device has been one of the remaining missing building blocks crucial to realize the concept of entirely printable electronics. Here, we position the novel topic of printable magnetic sensorics in a family of printable electronics and highlight possible application directions of this technology.     

Nanostructures for magnetically triggered release of drugs and biomolecules

Specific targeting and controlled release are crucial factors in the administration of drugs and therapeutic biomolecules. It has been shown that drug delivery systems can significantly benefit of the introduction of superparamagnetic nanoparticles in terms of both targeting and controlled release. Magnetic gradients can be used to target therapeutics to specific regions, while alternating magnetic fields produce frequency-dependent effects at the nanoparticle level. This review reports on the latest developments of multifunctional systems based on magnetic nanoparticles where the release of drugs and/or biomolecules is triggered by the application of an external magnetic field. The potentials of these systems are presented through examples in the fields of surface functionalized magnetic nanoparticles, magnetic polymer nanocomposites and magnetoliposomes. Recent results suggest the importance of integrating multiple functions within a single nanostructured device in order to successfully transport, localize and release drugs and biomolecules.     

A magnetically controlled MEMS device for drug delivery: design, fabrication, and testing

We report the development of a magnetically controlled drug delivery device for on-demand drug release to treat chronic diseases. The devices consist of drug-loaded micro-reservoirs (6 mm in diameter and ～550 μm in depth), sealed by magnetic PDMS (polydimethylsiloxane) membranes (? 6 mm × 40 μm) with laser-drilled apertures and actuated by an external magnetic field. We present a detailed analysis of the magnetic actuation forces and provide an estimate of the resulting membrane deflections. The reservoirs are fabricated by PDMS molding and loaded with drugs using solvent evaporation methods. Post-processing procedures using bovine serum albumin (BSA) adsorption on magnetic PDMS surfaces are carried out to modify the surface wettability and to allow water filling and dissolution of the drugs in the reservoirs. Detailed surface modification processes are described and characterized. The device demonstrates on-demand delivery of methylene blue (MB) as a model drug. Intermittent magnetic actuations of the device in a ～200 mT magnetic field show 10-fold increase in MB release compared to background release when the device is not actuated.     

有机自旋光电子学的基本过程

有机自旋光电子学的研究方向分为磁场效应和自旋注入两个方面.研究表明,外加低磁场能够显著改变非磁性有机半导体材料的光致发光、注入电流、电致发光和光电流.这称为有机半导体材料的磁场效应.近年来,非磁性有机半导体材料的磁场效应引起了广泛的关注和研究兴趣.首先,有机半导体材料的磁场效应是强有力的实验手段,用以研究有机电学、光学和光电器件中电荷传输和激发态中的有用和无用过程,为解决电荷传输和激发态过程中的瓶颈问题提供有效的实验手段,为实现磁-光-电多功能集成提供科学原理,尤其是磁场效应能够为提高能量转换效率、探测和传感光电子学器件的响应频谱范围和灵敏度提供新思路.同时利用磁电极,有机半导体材料和器件中自旋注入及其对电荷传输和激发态过程的调控可以用于发展新型功能化的自旋光电子学器件.本文综述并讨论了有机半导体材料和器件中的磁场效应和自旋注入的光电子学效应.     

A micropillar-integrated smart microfluidic device for specific capture and sorting of cells

An integrated smart microfluidic device consisting of nickel micropillars, microvalves, and microchannels was developed for specific capture and sorting of cells. A regular hexagonal array of nickel micropillars was integrated on the bottom of a microchannel by standard photolithography, which can generate strong induced magnetic field gradients under an external magnetic field to efficiently trap superparamagnetic beads (SPMBs) in a flowing stream, forming a bed with sufficient magnetic beads as a capture zone. Fluids could be manipulated by programmed controlling the integrated air-pressure-actuated microvalves, based on which in situ bio-functionalization of SPMBs trapped in the capture zone was realized by covalent attachment of specific proteins directly to their surface on the integrated microfluidic device. In this case, only small volumes of protein solutions (62.5 nL in the capture zone; 375 nL in total volume needed to fill the device from inlet A to the intersection of outlet channels F and G) can meet the need for protein! The newly designed microfluidic device reduced greatly chemical and biological reagent consumption and simplified drastically tedious manual handling. Based on the specific interaction between wheat germ agglutinin (WGA) and N-acetylglucosamine on the cell membrane, A549 cancer cells were effectively captured and sorted on the microfluidic device. Capture efficiency ranged from 62 to 74%. The integrated microfluidic device provides a reliable technique for cell sorting.     

Magnetic field effect on fluorescence in a mixture of N-ethylcarbazole and dimethyl terephthalate in a polymer film in the presence of electric fields

Magnetic field effects on the fluorescence spectrum and on the electrofluorescence spectrum (plots of the electric field-induced change in fluorescence intensity as a function of wavelength) have been examined in electron donor and acceptor pairs of N-ethylcarbazole (ECZ) and dimethyl terephthalate (DMTP) in polymer films at different ratios of donor/acceptor concentration. In the mixture having a high concentration of ECZ, electric field-induced quenching of the exciplex fluorescence originating from the photoinduced electron transfer becomes less efficient in the presence of a magnetic field. In the mixture having a low concentration of ECZ, on the other hand, no magnetic field effect was observed in the electrofluorescence spectrum, indicating that the hole carrier plays an important role in synergy effects of magnetic and electric field effects on exciplex fluorescence. In the absence of the applied electric field, the magnetic field does not affect either exciplex fluorescence with a peak at 450 nm or LE fluorescence emitted from the locally excited state of ECZ but enhances the broad emission with a peak at approximately 380 nm, probably assigned to the fluorescence of another type of exciplex between ECZ and DMTP. Thus, two kinds of magnetic field effects on fluorescence have been observed in a mixture of ECZ and DMTP in a polymer film.     

Magnetic control of bioelectrocatalytic processes based on assembled iron oxide particles

A facile magnetic control system was designed in bioelectrocatalytic process based on functionalized iron oxide particles. The iron oxide particles were modified with glucose oxidase, and ferrocene dicarboxylic acid was used as electron transfer mediator. Functionalized iron oxide particles can assemble along the direction of applied magnetic field, and the directional dependence of the assembled iron oxide particles can be utilized for device purposes. We report here how such functionalized magnetic particles are used to modulate the bioelectrocatalytic signal by changing the orientation of the applied magnetic field.