Immunoaffinity Extraction and Alternative Approaches for the Analysis of Toxins in Environmental, Food or Biological Matrices.

The evolution of instrumentation in terms of separation and detection allowed a real improvement of the sensitivity and analysis time. However, the analysis of ultra-traces of toxins in complex samples requires often a step of purification and even preconcentration before their chromatographic analysis. Therefore, immunoaffinity sorbents based on specific antibodies thus providing a molecular recognition mechanism appear as powerful tools for the selective extraction of a target molecule and its structural analogs to obtain more reliable and sensitive quantitative analysis in environmental, food or biological matrices. This review focuses on immunosorbents that have proven their efficiency in selectively extracting various types of toxins of various sizes (from small mycotoxins to large proteins) and physicochemical properties. Immunosorbents are now commercially available, and their use has been validated for numerous applications. The wide variety of samples to be analyzed, as well as extraction conditions and their impact on extraction yields, is discussed. In addition, their potential for purification and thus suppression of matrix effects, responsible for quantification problems especially in mass spectrometry, is presented. Due to their similar properties, molecularly imprinted polymers and aptamer-based sorbents that appear to be an interesting alternative to antibodies are also briefly addressed by comparing their potential with that of immunosorbents.

Microsphere Polymers in Molecular Imprinting: Current and Future Perspectives.

Molecularly imprinted polymers (MIPs) are specific crosslinked polymers that exhibit binding sites for template molecules. MIPs have been developed in various application areas of biology and chemistry; however, MIPs have some problems, including an irregular material shape. In recent years, studies have been conducted to overcome this drawback, with the synthesis of uniform microsphere MIPs or molecularly imprinted microspheres (MIMs). The polymer microsphere is limited to a minimum size of 5 nm and a molecular weight of 10,000 Da. This review describes the methods used to produce MIMs, such as precipitation polymerisation, controlled/'Living' radical precipitation polymerisation (CRPP), Pickering emulsion polymerisation and suspension polymerisation. In addition, some green chemistry aspects and future perspectives will also be given.

Advances in Molecularly Imprinting Technology for Bioanalytical Applications.

In recent years, along with the rapid development of relevant biological fields, there has been a tremendous motivation to combine molecular imprinting technology (MIT) with biosensing. In this situation, bioprobes and biosensors based on molecularly imprinted polymers (MIPs) have emerged as a reliable candidate for a comprehensive range of applications, from biomolecule detection to drug tracking. Unlike their precursors such as classic immunosensors based on antibody binding and natural receptor elements, MIPs create complementary cavities with stronger binding affinity, while their intrinsic artificial polymers facilitate their use in harsh environments. The major objective of this work is to review recent MIP bioprobes and biosensors, especially those used for biomolecules and drugs. In this review, MIP bioprobes and biosensors are categorized by sensing method, including optical sensing, electrochemical sensing, gravimetric sensing and magnetic sensing, respectively. The working mechanism(s) of each sensing method are thoroughly discussed. Moreover, this work aims to present the cutting-edge structures and modifiers offering higher properties and performances, and clearly point out recent efforts dedicated to introduce multi-sensing and multi-functional MIP bioprobes and biosensors applicable to interdisciplinary fields.

Molecularly Imprinted Polymers in Electrochemical and Optical Sensors.

Molecular imprinting is the process of template-induced formation of specific recognition sites in a polymer. Synthetic receptors prepared using molecular imprinting possess a unique combination of properties such as robustness, high affinity, specificity, and low-cost production, which makes them attractive alternatives to natural receptors. Improvements in polymer science and nanotechnology have contributed to enhanced performance of molecularly imprinted polymer (MIP) sensors. Encouragingly, recent years have seen an increase in high-quality publications describing MIP sensors for the determination of biomolecules, drugs of abuse, and explosives, driving toward applications of this technology in medical and forensic diagnostics. This review aims to provide a focused overview of the latest achievements made in MIP-based sensor technology, with emphasis on research toward real-life applications.

Recent progress for the selective pharmaceutical analyses using molecularly imprinted adsorbents and their related techniques: A review.

A well-organized molecularly imprinted polymer (MIP) provides the amazing selective molecular recognition ability, which have been close to natural enzymes and antibodies. One of the most efficient applications of MIPs is a selective separation and detection of pharmaceutical compounds in biological and/or environmental samples. MIP-based solid phase extraction now capacitates the selective concentration of the targeting compound from real samples. Also, many of the attractive methodological approaches and applications regarding the analysis of pharmaceutical samples using molecular imprinting technologies (MITs) have been reported in recent years. In this review, we summarize a part of the recent these works related to a new preparation concept of the adsorption adsorbents, sensitive sensor techniques, cell/bacteria separation, and drug delivery system. We believe that our concise summary will be of assistance to additional methodological MITs and highly selective separations/detections.

Control de la concentración de metilmercurio en productos pesqueros para el consumo humano mediante el empleo de polímeros de impronta molecular y de nanopartículas derivatizadas / Control of the methylmercury concentration in fish and seafood products for human consumption using molecularly imprinted polymers (MIPs) and derivatized nanoparticles

Objetivo: Desarrollar un polímero de impronta molecular para la determinación de metilmercurio en muestras de alimentos de origen marino. Material y métodos: Se sintetizó un polímero de impronta molecular (MIP) que emplea fenobarbital como ligando no vinilado para unirse al metilmercurio. Se utilizó la técnica de polimerización por precipitación. El MIP sintetizado fue empleado para funcionalizar nanopartículas magnéticas con el fin de mejorar el proceso de extracción del metilmercurio de las muestras. Resultados: El MIP con fenobarbital fue aplicado para la determinación de la concentración de metilmercurio en dos materiales de referencia de concentración certificada para el análisis de muestras de alimentos marinos (BCR-463, tejido de atún, y TORT-2, hepatopáncreas de langosta). Los valores de concentración experimentales obtenidos fueron de 3,04±0,16 μg/g y 0,152±0,013 μg/g respectivamente, coincidiendo con los valores certificados de forma estadísticamente significativa (test t, 95% confianza). Conclusiones: Se ha sintetizado un MIP para la determinación de la concentración de metilmercurio a bajas concentraciones en muestras de alimentos de origen marino (AU)

Objective: The development of a molecularly imprinted polymer support for methylmercury determination in fish and seafood samples. Materials and methods: A molecularly imprinted polymer was synthesized using the precipitation technique and phenobarbital as a non-vinylated ligand for binding methylmercury. The synthesized MIP was used for the functionalization of magnetic nanoparticles in order to improve the process of methylmercury extraction from the samples. Results: The MIP prepared with phenobarbital was applied to the determination of methylmercury concentration in two certified reference materials used for fish and seafood samples analysis (BCR-463, tuna fish, and TORT-2, lobster hepatopancreas). The experimental values (3.04±0.16 μg/g and 0.152±0.013 μg/g respectively) and the certified values showed no statistically significant difference (t test, 95% confidence level). Conclusions: We have synthesized a MIP for determining methylmercury in fish and seafood samples at low concentrations (AU)

Future of biosensors: a personal view.

Biosensors representing the technological counterpart of living senses have found routine application in amperometric enzyme electrodes for decentralized blood glucose measurement, interaction analysis by surface plasmon resonance in drug development, and to some extent DNA chips for expression analysis and enzyme polymorphisms. These technologies have already reached a highly advanced level and need minor improvement at most. The dream of the "100-dollar" personal genome may come true in the next few years provided that the technological hurdles of nanopore technology or of polymerase-based single molecule sequencing can be overcome. Tailor-made recognition elements for biosensors including membrane-bound enzymes and receptors will be prepared by cell-free protein synthesis. As alternatives for biological recognition elements, molecularly imprinted polymers (MIPs) have been created. They have the potential to substitute antibodies in biosensors and biochips for the measurement of low-molecular-weight substances, proteins, viruses, and living cells. They are more stable than proteins and can be produced in large amounts by chemical synthesis. Integration of nanomaterials, especially of graphene, could lead to new miniaturized biosensors with high sensitivity and ultrafast response. In the future individual therapy will include genetic profiling of isoenzymes and polymorphic forms of drug-metabolizing enzymes especially of the cytochrome P450 family. For defining the pharmacokinetics including the clearance of a given genotype enzyme electrodes will be a useful tool. For decentralized online patient control or the integration into everyday "consumables" such as drinking water, foods, hygienic articles, clothing, or for control of air conditioners in buildings and cars and swimming pools, a new generation of "autonomous" biosensors will emerge.

Developments and trends of molecularly imprinted solid-phase microextraction.

This review focuses on a solid-phase microextraction (SPME) method coupled with molecularly imprinted polymers (MIPs), namely molecularly imprinted solid-phase microextraction (MISPME). The first two sections discuss the summaries of conventional SPME and MIPs. The third section reviews the development of MISPME in past years, including the preparation of MISPME, and the applications to compounds in real samples.

[Current progress in research on the nanomaterials for biological macromolecules recognition].

The combination of nanotechnology and molecular imprinting technique, including their application research in biomedical domain, provides a new solution to the problem of the substitutes for antibodies, enzymes, and other native biological structures as well as cell bracket materials. Nanocavity biomaterials with recognition specificity imprinted by using proteins as templates have numerous applications in biotechnology, medicine and so on. This review presents the aspects of molecular imprinting nanostructure involved in the biomacromolecules imprinting, and it explores the precent developments and achievements of nanomaterials for molecular imprinting technology.

Current practices for describing the performance of molecularly imprinted polymers can be misleading and may be hampering the development of the field.

A contributing factor to the labored advance of molecularly imprinting as a viable commercial solution to molecular recognition needs is the absence of a standard and robust method for assessing and reporting on molecular imprinted polymer (MIP) performance. The diversity and at times inappropriateness of MIP performance indicators means that the usefulness of the literature back-catalogue, for predicting, elucidating or understanding patterns in MIP efficacy, remains largely inaccessible. We hereby put forward the case that the simple binding isotherm is the most versatile and useful method of assessing and reporting MIP function, allowing direct comparison between polymers prepared and evaluated in different studies. In this study we describe how to correctly plot and interpret a bound / free isotherm and show how such plots can be readily used to predict outcomes, retro-analyze data and optimize experimental design. We propose that by adopting the use of correctly constructed isotherms as the primary form of data representation researchers will enable inter-laboratory comparisons, promote good experimental design and encourage a greater collective understanding of molecular imprinting.

Molecularly imprinted polymers: present and future prospective.

Molecular Imprinting Technology (MIT) is a technique to design artificial receptors with a predetermined selectivity and specificity for a given analyte, which can be used as ideal materials in various application fields. Molecularly Imprinted Polymers (MIPs), the polymeric matrices obtained using the imprinting technology, are robust molecular recognition elements able to mimic natural recognition entities, such as antibodies and biological receptors, useful to separate and analyze complicated samples such as biological fluids and environmental samples. The scope of this review is to provide a general overview on MIPs field discussing first general aspects in MIP preparation and then dealing with various application aspects. This review aims to outline the molecularly imprinted process and present a summary of principal application fields of molecularly imprinted polymers, focusing on chemical sensing, separation science, drug delivery and catalysis. Some significant aspects about preparation and application of the molecular imprinting polymers with examples taken from the recent literature will be discussed. Theoretical and experimental parameters for MIPs design in terms of the interaction between template and polymer functionalities will be considered and synthesis methods for the improvement of MIP recognition properties will also be presented.

Chemically functionalized surface patterning.

Patterning substrates with versatile chemical functionalities from micro- to nanometer scale is a long-standing and interesting topic. This review provides an overview of a range of techniques commonly used for surface patterning. The first section briefly introduces conventional micropatterning tools, such as photolithography and microcontact printing. The second section focuses on the currently used nanolithographic techniques, for example, scanning probe lithography (SPL), and their applications in surface patterning. Their advantages and disadvantages are also demonstrated. In the last section, dip-pen nanolithography (DPN) is emphatically illustrated, with a particular stress on the patterning and applications of biomolecules.

[Recent advances and perspective in the study of the molecular imprinting of proteins].

Molecular imprinting technique (MIT) involves the synthesis of polymer in the presence of a template to produce complementary binding sites in terms of its size, shape, and functional group orientation. Such kind of polymer possesses specific recognition ability towards its template molecule. Despite the rapid development of MIT over the years, the majority of the template molecules that have been studied are small molecules, while molecular imprinting of proteins remains a significant yet challenging task due to their large size, structural flexibility and complex conformation. In this review, we summarize the research findings over the past five years, and discuss the characteristics of the technique, the most recent progress and the perspective in the field of molecular imprinting of proteins.

Too large to fit? Recent developments in macromolecular imprinting.

Molecular imprinting involves the synthesis of polymers in the presence of a template to produce complementary binding sites with specific recognition ability. The technique has been successfully applied as a measurement and separation technology, producing a uniquely robust and antibody-like polymeric material. Low molecular weight molecules have been extensively exploited as imprint templates, leading to significant achievements in solid-phase extraction, sensing and enzyme-like catalysis. By contrast, macromolecular imprinting remains underdeveloped, principally because of the lack of binding site accessibility. In this review, we focus on the most recent developments in this area, not only covering the widespread use of biological macro-templates but also highlighting the emerging use of synthetic macro-templates, such as dendrimers and hyperbranched polymers.