Fluorescent imprinted polymers prepared with 2-acrylamidoquinoline as a signaling monomer

[structure: see text] A cyclobarbital-selective molecularly imprinted polymer was prepared using a fluorescent functional monomer, 2-acrylamidoquinoline. This monomer was designed to increase in fluorescence intensity upon hydrogen bonding to the cyclobarbital guest. The resultant imprinted polymers exhibited the enhancement of the fluorescence intensity when cyclobarbital was bound. Our results show that this fluorescent responsive imprinting method could be useful in the development of sensors for quantification of nonfluorescent compounds.     

分子烙印传感器的研究进展

分子烙印技术是制备具有选择性分子识别能力的聚合物的新兴技术,其应用之一是将分子烙印聚合物用作分析化学中化学传感器的识别元件。本文综述了分子烙印技术的原理方法及其在传感器方面的应用,评述了分子烙印传感器的发展方向,展望了其在有机磷化合物检测中的应用前景。     

Core-shell nanostructured molecular imprinting fluorescent chemosensor for selective detection of atrazine herbicide

To convert the binding events on molecularly imprinted polymers (MIPs) into physically detectable signals and to extract the templates completely are the great challenges in developing MIP-based sensors. In this paper, a core-shell nanostructure was employed in constructing the MIP chemosensor for the improvements of template extraction efficiency and imprinted sites accessibility. Vinyl-substituted zinc(II) protoporphyrin (ZnPP) was used as both fluorescent reporter and functional monomer to synthesize atrazine-imprinted polymer shell at silica nanoparticle cores. The template atrazine coordinates with the Lewis acid binding site Zn of ZnPP to form a complex for the molecular imprinting polymerization. These imprinted sites are located in polymer matrix of the thin shells (~8 nm), possessing better accessibility and lower mass-transfer resistance for the target molecules. The fluorescence properties of ZnPP around the imprinted sites will vary upon rebinding of atrazine to these imprinted sites, realizing the conversion of rebinding events into detectable signals by monitoring fluorescence spectra. This MIP probe showed a limit of detection (LOD) of about 1.8 μM for atrazine detection. The core-shell nanostructured MIP method not only improves the sensitivity, but also shows high selectivity for atrazine detection when compared with the non-molecular imprinted counterparts.     

Molecular Imprinting Fibrous Membranes of Poly（ acrylonitrile-co-acrylic acid） Prepared by Electrospinning

Introduction Overthepastfewdecades,molecularimprinting hasbeendescribedasatechnologyforpreparing“mo leculardoors”whichcanbematchedto“template keys”.Ithasbeenfoundtobeasimpleandeffective approachtointroducespecificrecognitionsitesintosyn theticpolymers…     

A new type of boronic acid fluorescent reporter compound for sugar recognition

Fluorescent boronic acids that change fluorescent properties upon carbohydrate binding are very useful for the preparation of fluorescent sensors for sugars. Herein we report 5-quinolineboronic acid (5-QBA) that shows significant fluorescent property changes through a unique pK_a-switching mechanism upon binding a diol in aqueous solution.     

分子印迹聚合物的制备及其传感器应用研究

分子印迹技术于近十年内得到了飞速的发展,已经成为当前研究的热点之一.本文主要介绍了分子印迹聚合物的原理以及一些常用制备方法.分子印迹聚合物的一个重要应用是在化学传感器中作为识别元件,研制稳定、低成本的分子印迹传感器.分子印迹聚合物在传感器领域的应用是分子印迹技术的一个重要方面,本文综述了分子印迹聚合物在化学传感器方面的应用研究现状,并对分子印迹传感器的发展前景进行了评述.     

米诺地尔分子印迹聚合物的制备与吸附性能

以吸附量为评价指标,筛选米诺地尔分子印迹聚合物的合成条件。结果表明,制备该聚合物的较佳反应条件是V_(甲醇)/V_(乙腈)=1∶3为致孔剂、a-甲基丙烯酸(MAA)为功能单体、n_(米诺地尔)/n_(MAA)/n_(交联剂)=1∶6∶20,采用筛选出的合成条件制备出的分子印迹聚合物,对模板分子有良好的吸附性能。     

A unique approach to development of near-infrared fluorescent sensors for in vivo imaging

Near-infrared (NIR) fluorescent sensors have emerged as promising molecular tools for imaging biomolecules in living systems. However, NIR fluorescent sensors are very challenging to be developed. Herein, we describe the discovery of a new class of NIR fluorescent dyes represented by 1a/1c/1e, which are superior to the traditional 7-hydroxycoumarin and fluorescein with both absorption and emission in the NIR region while retaining an optically tunable hydroxyl group. Quantum chemical calculations with the B3LYP exchange functional employing 6-31G(d) basis sets provide insights into the optical property distinctions between 1a/1c/1e and their alkoxy derivatives. The unique optical properties of the new type of fluorescent dyes can be exploited as a useful strategy for development of NIR fluorescent sensors. Employing this strategy, two different types of NIR fluorescent sensors, NIR-H(2)O(2) and NIR-thiol, for H(2)O(2) and thiols, respectively, were constructed. These novel sensors respond to H(2)O(2) or thiols with a large turn-on NIR fluorescence signal upon excitation in the NIR region. Furthermore, NIR-H(2)O(2) and NIR-thiol are capable of imaging endogenously produced H(2)O(2) and thiols, respectively, not only in living cells but also in living mice, demonstrating the value of the new NIR fluorescent sensor design strategy. The new type of NIR dyes presented herein may open up new opportunities for the development of NIR fluorescent sensors based on the hydroxyl functionalized reactive sites for biological imaging applications in living animals.     

Design of fluorescent materials for chemical sensing

There is an enormous demand for chemical sensors for many areas and disciplines. High sensitivity and ease of operation are two main issues for sensor development. Fluorescence techniques can easily fulfill these requirements and therefore fluorescent-based sensors appear as one of the most promising candidates for chemical sensing. However, the development of sensors is not trivial; material science, molecular recognition and device implementation are some of the aspects that play a role in the design of sensors. The development of fluorescent sensing materials is increasingly captivating the attention of the scientists because its implementation as a truly sensory system is straightforward. This critical review shows the use of polymers, sol-gels, mesoporous materials, surfactant aggregates, quantum dots, and glass or gold surfaces, combined with different chemical approaches for the development of fluorescent sensing materials. Representative examples have been selected and they are commented here.     

Computer‐aided design and synthesis of CdTe@SiO2 core–shell molecularly imprinted polymers as a fluorescent sensor for the selective determination of sulfamethoxazole in milk and lake water

In this work, a molecular dynamics simulation method was introduced to compute the preassembled system of molecular imprinted polymers for sulfamethoxazole monomer. The results revealed that the ratio of sulfamethoxazole as template molecule to 3‐aminopropyltriethoxysilane as functional monomer to tetraethylorthosilicate as cross‐linker of 10:10:40 led to the most stable template‐functional monomer cluster. Based on the result of computational simulation, CdTe@SiO₂ core–shell imprinted polymers, a cadmium telluride quantum dots layer on the surface of aminofunctionalized SiO₂, were synthesized as the fluorescent sensor. Then, a series of measures were used to characterize the structure and morphology to get optimal sensors. The concentration range was 5.0–30.0 μmol/L between molecular imprinted polymers at CdTe at SiO₂, and sulfamethoxazole of the fluorescence intensity. To further verify the reliability and accuracy of the fluorescent sensor, the application was successfully by analyzing sulfamethoxazole in pure milk and lake water. The results showed the recoveries were above 96.89% with a relative standard deviation of 1.25–5.45%, and the fluorescence sensor with selective recognition provides an alternative solution for the determination of sulfamethoxazole.     

A new boronic acid fluorescent reporter that changes emission intensities at three wavelengths upon sugar binding

The boronic acid moiety is a very useful functional group for the preparation of sugar sensors. Along this line, water-soluble boronic acids that change fluorescent properties upon sugar binding are especially useful as reporter units in fluorescent sensors for carbohydrates. Herein, we report the discovery of a new water-soluble boronic acid (1, dibenzofuran-4-boronic acid) that exhibits unique fluorescence changes at three wavelengths upon binding with sugars under near physiological conditions.     

分子印迹SiO2纳米管膜的制备及其生化分离应用

分子印迹技术(M IT)是20世纪末出现的一种高选择性分离技术,由于M IT模仿了生物界的锁钥作用原理,使制备的材料(M IT polymer,M IP)具有极高的选择性.同时,M IP又是人工合成的高分子,具有非常好的稳定性,并且制备简单,因此在固相萃取、不对称催化和传感器等相关领域得到了广泛的应用[1～5].目前,M IT存在的主要问题是所制备的M IP对目标分子的结合量小,可接触性差,达到结合平衡的时间长,且在制备过程中所使用的印迹分子难以完全洗脱.     

Capturing molecules with templated materials--analysis and rational design of molecularly imprinted polymers

The creation of synthetic tailor-made receptors capable of recognizing desired molecular targets with high affinity and selectivity is a persistent long-term goal for researchers in the fields of chemical, biological, and pharmaceutical research. Compared to biomacromolecular receptors, these synthetic receptors promise simplified production and processing, less costs, and more robust receptor architectures. During recent decades, molecularly imprinted polymers (MIPs) are widely considered mimics of natural molecular receptors suitable for a diversity of applications ranging from biomimetic sensors, to separations and biocatalysis.A remaining challenge for the next generation of MIPs is the synthesis of deliberately designed and highly efficient receptor architectures suitable for recognizing biologically relevant molecules, for which natural receptors are either not prevalent, or difficult to isolate and utilize. Hence, this review discusses recent advances in synthetic receptor technology for biomolecules (e.g. drugs, amino acids, steroids, proteins, entire cells, etc.) via molecular imprinting techniques. Surface imprinting methods and epitope imprinting approaches have been introduced for protein recognition at imprinted surfaces. Imprinting techniques in aqueous solution or organic-water co-solvents have been introduced avoiding denaturation of biomolecules during MIP synthesis. In addition, improved bioreactivity of entire enzyme or active site mimics generated by molecular imprinting will be highlighted. Finally, the emerging importance of molecular modeling and molecular dynamics studies detailing the intermolecular interactions between the template species, the porogenic solvent molecules, and the involved monomer and cross-linker in the pre-polymerization solution will be addressed yielding a rational approach toward next-generation MIP technology.     

Rational Design of In Situ Monolithic Imprinted Polymer Membranes for the Potentiometric Sensing of Diethyl Chlorophosphate – a Chemical Warfare Agent Simulant

Molecularly imprinted polymer membrane was prepared by semicovalent imprinting strategy wherein i) the template diethyl chlorophosphate (DCP), (a simulant of organophosphorous nerve agents), is covalently linked to the reactive functional monomer vinyl aniline (VA) during imprinting step followed by noncovalent rebinding and ii) in situ polymerization via single pot synthesis in presence of additional functional monomer, 2‐hydroxyethyl methacrylate (HEMA) and crosslinking monomer, ethylene glycol dimethacrylate (EGDMA) after addition of 2‐nitrophenyl octyl ether (NPOE) and 2,2′‐azobisisobutyronitrile (AIBN) as plasticizer and initiator respectively. The resulting membrane is integrated with a potentiometric transducer while designing a DCP sensor. The fabricated sensor responds over a wider concentration range of 10^?6–10^?2 M with a lower detection limit of 10^?6 M (0.17 ppm). In addition, in situ monolithic membrane based sensor was designed by adopting noncovalent imprinting strategy also. A detailed comparison is made between semicovalent and noncovalent in situ membrane based sensors on the prime sensor performance criteria such as sensitivity, selectivity, working range, response time, reusability and reversibility. Again, the relative merits and demerits of semicovalent vis‐à‐vis noncovalent strategy based in situ monolithic membrane sensors were also highlighted. The probable molecular recognition mechanism is also discussed.     

Targetable fluorescent sensors for advanced cell function analysis

Chemistry-based bioimaging techniques have contributed to the elucidation of intracellular physiological events. During the last few decades, many fluorescent sensors have been developed and used in live cell experiments. Owing to immense efforts by numerous research groups, several strategies have been developed to design fluorescent sensors based on various components such as small molecules and fluorescent proteins. Recently, site-specific targeting of fluorescent sensors has attracted increasing attention. Strategies for fluorescent sensor targeting were surveyed in this review with the aims to expand current knowledge on chemistry-based bioimaging and aid in the emergence of related innovative technologies. The first discussed strategy is based on the intrinsic properties of small molecules for localization at specific organelles, such as mitochondria, nuclei, and lysosomes. As a further elaboration of the topic, our recent study about in vivo targeting of pH sensors was briefly introduced. The second strategy exploits genetically encoded tags and their specific ligands. Here, fluorescent sensors with commercially available tags and corresponding ligands were mainly reviewed. As the final topic, our original protein labeling technique, which enables fluorogenic labeling as an advanced technology, was introduced.     

Protein-imprinted materials: rational design, application and challenges

Protein imprinting is a promising tool for generating artificial biomimetic receptors with antibody-like specific recognition sites. Recently, protein-imprinted materials, as potential antibody substitutes, have attracted much attention in many fields, for example chemical sensors, chromatographic stationary phases, and artificial enzymes, owing to their long-term storage stability, potential re-usability, resistance to harsh environment, and low cost. In this critical review, we focus our discussion on the rational preparation of protein-imprinted materials in terms of choice of template, functional monomer, crosslinker, and polymerization format. In addition, several highlighted applications of protein-imprinted materials are emphasized, not only in well-known fields but also in some unique fields, for example proteomics and tissue engineering. Finally, we propose challenges arising from the intrinsic properties of protein imprinting, for example obtaining the template, heterogeneous binding, and extrinsic competition, for example immobilized aptamers.     

分子印迹聚合物传感器研究

分子印迹聚合物(molecular imprinting polymers,MIPs)是利用分子印迹技术合成的一种交联高聚物.分子印迹技术(molecular imprinting technique,MIT)是在近十几年来才发展起来的一门边缘科学技术.它结合了高分子化学、生物化学等学科,是模拟抗体-抗原相互作用的一种新技术,具有选择性识别位点的性质,作为传感器的理想敏感材料的制备方法日益受到研究者们的重视.本文综述了分子印迹技术的原理和分子印迹聚合物的制备方法,及其应用于传感器敏感材料的研究现状,并展望了其发展前景.     

硅胶表面亮菌甲素分子印迹聚合物的制备及其性能研究

采用光接枝印迹方法,在硅胶微球表面制备了以亮菌甲素为模板分子、2-乙烯基吡啶为功能单体的分子印迹聚合物,采用荧光法优选了功能单体及比例,进一步用荧光法对印迹聚合物的吸附特性和印迹效率进行评价.结果表明.该印迹聚合物对模板分子具有特异吸附性能,印迹效率为48.6%.     

Recent Advances in Excimer-Based Fluorescence Probes for Biological Applications

The fluorescent probe is a powerful tool for biological sensing and optical imaging, which can directly display analytes at the molecular level. It provides not only direct visualization of biological structures and processes, but also the capability of drug delivery systems regarding the target therapy. Conventional fluorescent probes are mainly based on monomer emission which has two distinguishing shortcomings in practice: small Stokes shifts and short lifetimes. Compared with monomer-based emission, excimer-based fluorescent probes have large Stokes shifts and long lifetimes which benefit biological applications. Recent progress in excimer-based fluorescent sensors (organic small molecules only) for biological applications are highlighted in this review, including materials and mechanisms as well as their representative applications. The progress suggests that excimer-based fluorescent probes have advantages and potential for bioanalytical applications.     

Nanoscale fluorescent sensors for intracellular analysis

There is a growing interest in the development of submicron optochemical sensing devices. Miniaturization of sensors to nano-dimensions decreases their typical response time down to the millisecond time scale. Their penetration volume is reduced to a few cubic micrometers and they exhibit a spatial resolution at the nanometer scale. In this review the fabrication of submicron optical fiber fluorescent sensors and particle-based fluorescent nanosensors is described. The functional characteristics of these exciting miniaturized fluorescent sensors and their applications for quantitative measurement of intracellular analytes are demonstrated.