分子印迹溶胶-凝胶材料的制备及应用

分子印迹技术是制备对特定分子具有选择性识别的聚合物的技术。分子印迹技术与溶胶-凝胶过程相结合,可设计多孔无机主体,增强分子识别能力,并具有极好的热稳定性和水解稳定性。改变溶胶-凝胶过程的条件,可制备具有最佳孔隙率和表面积,并用于分离复杂的混合物、选择性吸附富集模板分子(或目标分子)、催化、微合成器应用的分子印迹溶胶-凝胶材料。综述了溶胶．凝胶技术和分子印迹技术的特点,分子印迹溶胶-凝胶技术和分子印迹溶胶．凝胶材料的概念、基本原理、制备方法及应用。     

Applications of molecularly imprinted materials as selective adsorbents: Emphasis on enzymatic equilibrium shifting and library screening

Summary Molecular imprinting is an attractive method for producing highly selective adsorbents, and several new and potentially useful applications based on molecularly imprinted polymers (MIPs) have been described in recent years. In this article, we highlight some of the areas where these materials have found application, and also describe some new fields of application where the selectivities of imprinted materials can be gainfully employed, for example as binding matrices in the screening of combinatorial libraries, and as auxiliary agents in enzymatic syntheses. Presented at: Affinity Chromatography Conference, Cambridge, UK, July 1–3, 1997.     

蛋白质分子印迹

分子印迹技术是一种新型的高效分离技术，具有空间选择性识别特性。本文介绍了分子印迹技术在蛋白质大分子上的应用和发展，包括蛋白质分子印迹选用的单体和交联剂、印迹方法、印迹机理、蛋白质分子印迹技术的应用以及存在的一些问题。     

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.     

Molecular imprinting in ultrathin titania gel films via surface sol-gel process

Recent progresses of molecular imprinting in metal oxide matrices were summarized. Application of the surface sol-gel process to mixtures of organic carboxylic acids and titanium alkoxide provides ultrathin layers of titania gel (10-20 nm thick), in which molecule-sized cavities are kept intact upon removal of the organic templates. The imprinted cavity reflects the structural and functional features of the template molecule, and the enantioselective imprinting of dipeptide isomers is observed. Robustness and flexibility of the ultrathin titania layer is demonstrated by the formation of interconnected titania hollow structures. Possible practical applications and unsolved problems of this technique are discussed.     

A comparative study of the potential of acrylic and sol-gel polymers for molecular imprinting

The successful molecular imprinting of 2-aminopyridine (2-apy) in bulk polymerisations of acrylic and sol-gel based polymers has been achieved. Both polymeric systems reveal varying degrees of affinity in rebinding the original template as well as a number of structural analogues. Rebinding was conducted in chloroform, acetonitrile and methanol in order to assess the role of hydrogen bonding in imprinting. The acrylic imprinted polymer retained approximately 50% of the template in rebinding studies in chloroform compared to 100% for the sol-gel. However, this higher affinity for the sol-gel was accompanied by a higher degree of non-specific binding. While the acrylic polymer performed poorly in acetonitrile, the sol-gel maintained a high degree of discrimination.The acrylic polymer exhibited little discrimination between imprinted and reference polymers for 3-aminopyridine (3-apy) indicating the high selectivity of the MIP polymer for 2-apy relative to 3-apy. This selectivity was reduced in acetonitrile. Selectivity of the sol-gel for 2-apy in chloroform was poor as 3-apy was retained to a similar degree. Comparable results were obtained in acetonitrile. 4-Aminopyridine (4-apy) bound strongly to all polymers in all solvents and proved very difficult to remove due to the high degree of non-specific binding for both polymeric matrices.     

Small organic molecular imprinted materials: their preparation and application

Molecular imprinting is a technique for preparing polymeric materials that are capable of recognizing and binding the desired molecular target with a high affinity and selectivity. The materials can be applied to a wide range of target molecules, even those for which no natural binder exists or whose antibodies are difficult to raise. The imprinting of small organic molecules (e.g., pharmaceuticals, pesticides, amino acids, steroids, and sugars) is now almost routine. In this review, we pay special attention to the synthesis and application of molecular imprinted polymer (MIPs) imprinted with small organic molecules, including herbicides, pesticides, and drugs. The advantages, applications, and recent developments in small organic molecular imprinted technology are highlighted.     

Molecularly imprinted polymers as biomimetic catalysts

The quest for synthetic biomimetic catalysts able to complement the activity of enzymes has attracted substantial research efforts, and the molecular imprinting approach is one of the attractive techniques that are currently being investigated. In the last 3 years, there has been considerable interest in studying in greater detail the parameters that control and influence the catalytic activity of imprinted polymers and applying molecular imprinting to a wider range of polymeric matrices. This article reports on some of the interesting examples available in the literature regarding the use of metal-containing polymers, microgels and nanogels and thermoresponsive polymers.     

自组装碳纳米管-氯洁霉素分子印迹溶胶-凝胶电化学传感器研究

结合自组装技术, 采用电聚合方法在碳纳米管修饰金电极表面制备对氯洁霉素具有特异性识别位点的分子印迹溶胶-凝胶薄膜, 成功构建了一种新型印迹溶胶-凝胶电化学传感器. 通过循环伏安法(CV)、示差脉冲法(DPV)、安培计时法(I-t)和扫描电镜(SEM)表征了该印迹溶胶-凝胶膜的电化学性能和表面形貌. 结果表明, 该传感器具有良好的选择性和灵敏度, 氯洁霉素在多壁碳纳米管修饰的印迹溶胶-凝胶传感器上的响应明显提高. 该印迹溶胶-凝胶传感器对氯洁霉素的浓度响应线性范围为5.0×10^-7~8.0×10^-5 mol/L, 检出限为2.44×10^-8 mol/L. 该传感器被成功地用于人体尿液中氯洁霉素的分析测定.     

基于N-异丙基丙烯酰胺的温敏型分子印迹聚合物

温敏型分子印迹技术是近几年来分子印迹技术新的发展。温敏型分子印迹聚合物以低交联度为特征,对模板分子的吸附容量和选择性随温度变化而改变。本文总结并评述了基于N-异丙基丙烯酰胺的温敏型MIP分子印迹聚合物及其制备方法,指出了温敏型分子印迹技术发展中需要解决的问题。     

Chiral recognition applications of molecularly imprinted polymers: a critical review

Molecular imprinting technology offers the unique opportunity to tailor chiral stationary phases with predefined chiral recognition properties by employing the enantiomers of interest as binding-site-forming templates. Added advantages, such as ease of preparation, chemical robustness, low-cost production, and the possibility of shaping molecularly imprinted polymers (MIPs) in various self-supporting formats, render them attractive materials for a broad range of chiral recognition applications. In this review a critical overview on recent developments in the field of MIP-based chiral recognition applications is given, focusing on separation techniques and molecular sensing. Inherent limitations associated with the use of enantioselective MIP materials in high-performance separation techniques are outlined, including binding site heterogeneity and slow mass transfer characteristics. The prospects of MIP materials as versatile recognition elements for the design of enantioselective sensor systems are highlighted.     

Imprinted polymers-tailor-made mimics of antibodies and receptors

The technique of molecular imprinting allows the formation of specific recognition sites in synthetic polymers through the use of templates or imprint molecules. These recognition sites mimic the binding sites of antibodies and other biological receptor molecules. Molecularly imprinted polymers can therefore be used in applications relying on specific molecular binding events. The stability, ease of preparation and low cost of these materials make them particularly attractive. This review focuses on recent developments and advances in the field of molecularly imprinted materials, with special emphasis on applications in immunoassays and sensors recently developed by our group and by others.     

Rational design of biomimetic molecularly imprinted materials: theoretical and computational strategies for guiding nanoscale structured polymer development

In principle, molecularly imprinted polymer science and technology provides a means for ready access to nano-structured polymeric materials of predetermined selectivity. The versatility of the technique has brought it to the attention of many working with the development of nanomaterials with biological or biomimetic properties for use as therapeutics or in medical devices. Nonetheless, the further evolution of the field necessitates the development of robust predictive tools capable of handling the complexity of molecular imprinting systems. The rapid growth in computer power and software over the past decade has opened new possibilities for simulating aspects of the complex molecular imprinting process. We present here a survey of the current status of the use of in silico-based approaches to aspects of molecular imprinting. Finally, we highlight areas where ongoing and future efforts should yield information critical to our understanding of the underlying mechanisms sufficient to permit the rational design of molecularly imprinted polymers.     

Preparation of quercetin imprinted core-shell organosilicate microspheres using surface imprinting technique

In this work,the quercetin imprinted core-shell microspheres were prepared using silica surface imprinting technique.A simple sol-gel procedure was used for the synthesis of the imprinted materials with 3-aminopropyltriethoxysilane as functional monomer and tetraethyl orthosilicate as crosslinker.The SEM images indicated that the MIPs shell was successfully grafted onto the silica surface.The characteristics of the molecularly imprinted polymers such as capacity,selectivity and absorption dynamic were investigated by rebinding experiments.The results showed that the prepared MIPs had good imprinting effect and adsorption amount of quercetin.     

Selective silica‐based sorbent materials synthesized by molecular imprinting for adsorption of pharmaceuticals in aqueous matrices

The presence of pharmaceuticals in aqueous environmental matrices often requires efficient and selective preconcentration procedures. Thus, silicas (SILs) were synthesized by a molecular imprinting technique using an acid‐catalyzed sol‐gel process and the following drugs as templates: fluoxetine, gentamicin, lidocaine, morphine, nifedipine, paracetamol, and tetracycline. The materials were subjected to sorbent extraction assisted by ultrasonic treatment to remove the drugs and the consequent formation of molecular imprinted cavities. The surface area of the resulting materials ranged from 290 to 960 m²/g. Adsorption tests were performed with the molecular imprinting phases. In terms of the potential selectivity, the SILs were subjected to the adsorption of drugs from samples such as potable and surface water. The adsorption capacity remained in the range between 55 and 65% for both matrices, while for the nonimprinted SIL it remained between 15 and 20%.     

Molecularly imprinted silica prepared with immiscible ionic liquid as solvent and porogen for selective recognition of testosterone

1-Butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF₄), an ionic liquid (IL) immiscible with water, was used as a new type of solvent and porogen for the preparation of molecularly imprinted silica. The new imprinted silica was prepared by a sacrificial spacer molecular imprinting approach with testosterone as template molecule. The new covalent monomer-template complex used in the imprinting procedure was synthesized via the reaction of 3-(triethoxysilyl)propyl isocyanate with testosterone. The imprinted silica was characterized by FT-IR spectroscopy, N₂ gas adsorption–desorption isotherm and the high-resolution transmission electron microscopy. Moreover, the selective adsorption ability of the imprinted particles towards testosterone was investigated by the steady-state binding experiment with testosterone propionate as its structural analogue. Results showed that the imprinted silica obtained in this study had relatively homogenous structure with numerous mesopores, indicating that the IL used here is an excellent solvent and satisfactory porogen for the preparation of imprinted materials. Moreover, ILs are more environmentally friendly than traditional organic solvents due to their negligible vapor pressure. The imprinted silica possesses highly specific recognition property and high binding capacity towards testosterone, showing that the new imprinting technique is relatively successful.     

表面分子(离子)印迹硅胶/聚合物的制备及性能研究进展

分子印迹技术(MIT)是制备对模板分子具有专一识别能力聚合物的技术。目前,把识别位点建立在基质表面的表面印迹技术日益受到重视,它可以提高识别位点与印迹分子的结合速度,进一步加强印迹材料吸附分离效率,硅胶因其具有良好的机械稳定性和热稳定性,吸附选择性高等优点,作为表面印迹的基质显示出较大的优越性。本文详细综述了有机分子印迹硅胶/聚合物及金属离子印迹硅胶/聚合物的制备和性能的研究进展,并对印迹材料将来的应用进行了展望。     

Electrochemistry of molecular imprinting of large entities

Molecularly imprinted polymer (MIP) is a well-known approach, in which cavities with specific affinity are formed. These functional materials are used mostly for the separation, sensing, and catalysis of small molecules. In the last two decades, the MIP concept has been expanded for the imprinting of large entities such as nanoparticles, viruses, and cells. In this emerging field termed surface imprinted polymers (SIPs), a thin matrix imprints only part of the entity to enable its easy removal and rebinding.In this review, we focus on the different recent imprinting strategies for nanoparticles, viruses, and cells in conjunction with electrochemistry and describe their applications in the fields of biology, analytical chemistry, and medicine.     

Imprinted nanomaterials: a new class of synthetic receptors

The molecular imprinting approach provides a unique opportunity for the creation of three-dimensional cavities with tailored recognition properties. Over the last decade this field has expanded considerably, across a variety of disciplines, leading to novel approaches and many potential applications. Progress in the field of materials science has led to significant breakthroughs and the application of the imprinting approach to novel polymeric formats offers new insights and attractive methods for the preparation of synthetic receptors. In particular, nanomaterials have received considerable attention in the developing field of nanotechnology. With a large number of recent developments in the field of molecular imprinting available, this article is focused on a selection of new systems, in particular the different formats of nanomaterials, such as nanogels, nanofibres, nanowires and nanotubes.     

Solvent‐tunable colors in imprinted helical structures on polymer template via multiple UV‐induced polymerization

A solvent tunable single‐layer polymer film with a multipitched photonic structure as a new photonic band gap material has been developed by imprinting the helical structures on polymer matrices through multiple photocrosslinking in an induced chiral nematic mesophase. Here, the polymer matrices themselves served as a chiral template, which exhibited Bragg reflections in the absence of both a chiral dopant and anisotropic materials because of the memory effects of the polymer network. Tuning of colors was achieved by making a refractive index contrast in the two periodic media of imprinted solid helical structure and the isotropic liquids that fill it. On incorporation of various isotropic liquids in the imprinted matrices, a sharp peak in the reflection spectrum shifted drastically, which indicated that the wavelength shifts strongly depended on the sort of liquids that filled the matrices. The effects of temperature on the imprinted polymer template feeding the various liquids were studied through the reflectance spectra. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011