Application of molecularly imprinted polymers for electrochemical detection of some important biomedical markers and pathogens

The determination of biomedical markers and pathogens using electrochemical sensors is a well-established technique in which the transducer and the recognition element are used to detect the target molecule. There is a growing interest in molecularly imprinted polymer (MIPs) applications as promising recognition elements. The use of MIPs as recognition elements in electrochemical sensors offers the advantages of being fast, low cost, and, at the same time, provides accurate and selective results compared with other commonly applied routine methods for biomedical markers and pathogen detection. Compared with other nanomaterials and aptamer-based biosensors, MIP-based sensors offered excellent selectivity for low-priced reagents to be used. The aim of the current review is to discuss the most recent applications of MIP-based electrochemical sensors (2019–2021) as promising detection devices for some important biomarkers, enzymes, and pathogens, such as viruses, bacteria, and toxins.     

Molecularly imprinted polymers—potential and challenges in analytical chemistry

Among the variety of biomimetic recognition schemes utilizing supramolecular approaches molecularly imprinted polymers (MIPs) have proven their potential as synthetic receptors in numerous applications ranging from liquid chromatography to assays and sensor technology. Their inherent advantages compared to biochemical/biological recognition systems include robustness, storage endurance and lower costs. However, until recently only few contributions throughout the relevant literature describe quantitative analytical applications of MIPs for practically relevant analyte molecules and real-world samples. Increased motivation to thoroughly evaluate the true potential of MIP technology is clearly attributed to the demands of modern analytical chemistry, which include enhanced sensitivity, selectivity and applicability of molecular recognition building blocks at decreasing costs. In particular, the areas of environmental monitoring, food and beverage analysis and industrial process surveillance require analytical tools capable of discriminating chemicals with high molecular specificity considering increasing numbers of complex environmental contaminants, pollution of raw products and rigorous quality control requested by legislation and consumer protection. Furthermore, efficient product improvement and development of new products requires precise qualitative and quantitative analytical methods. Finally, environmental, food and process safety control issues favor the application of on-line in situ analytical methods with high molecular selectivity. While biorecognition schemes frequently suffer from degrading bioactivity and long-term stability when applied in real-world sample environments, MIPs serving as synthetic antibodies have successfully been applied as stationary phase separation matrix (e.g. HPLC and SPE), recognition component in bioassays (e.g. ELISA) or biomimetic recognition layer in chemical sensor systems. Examples such as MIP-based selective analysis of flavones/flavonoids in wine, the determination of mycotoxins in beverages and analysis of organic contaminants in environment samples will elucidate the perspectives of this technology and will be contrasted with the challenges of rational MIP design providing control on binding site density, receptor capacity and selectivity.     

Optical interrogation of molecularly imprinted polymers and development of MIP sensors: a review

This article reviews the progress and developments achieved in the past five years (2000–2005) in the application of optical analytical techniques to the evaluation of molecularly imprinted polymer (MIP) characteristics. The MIP binding efficiency, recognition processes and selectivity have been intensively studied by optical means due to the general high sensitivity and simplicity of the utilisation of optical techniques. In addition, recent progress in the covalent linkage of MIPs to optical transducers has allowed for the realisation of highly efficient and robust optical MIP-based molecular recognition sensors. The review provides insight into the various approaches to the optical interrogation of MIPs, and is organised according to the type of optical technique employed (fluorescence, UV/Vis and infrared spectroscopy, surface plasmon resonance, chemiluminescence, refractive interference spectroscopy and Raman scattering) and the detailed strategies applied. The review also covers the recent progress achieved in the area of optical sensors based on MIPs.     

片段/虚拟分子印迹聚合物的应用新进展

分子印迹聚合物(MIPs)是通过模拟酶与底物或抗原抗体特异性结合原理而制备的高分子聚合物,以其结构预定性、识别特异性、制备简便、成本低、耐受性强等优点而被广泛用于样品前处理、传感分析、生物医药、环境/食品分析等多个领域。目前已发展多种策略用于MIPs制备,达到简化制备过程或提高聚合物性能等目的,极大拓宽了MIPs的应用范围。对各种先进印迹策略及其组合使用的探索已成为MIPs制备的研究热点之一。其中,片段印迹策略和虚拟模板印迹策略备受青睐。片段印迹策略是选择目标分子中含有特定官能团的一部分(片段结构)作为模板进行印迹,通过对片段的识别达到对整个分子的识别,能够克服某些目标物不易获得或体积较大不适合作为模板的问题,为印迹易失活、易传染的目标物及整体印迹困难的大分子提供可行的方法。虚拟模板印迹策略是选用与目标物特异性结构相似或相同的其他物质代替目标物作为模板制备MIPs,可在很大程度上解决模板不易获得或较昂贵等问题,以及避免模板可能泄漏对结果造成的影响,尤其适用于目标物造价高、具有感染性、易燃易爆、易降解等不适合作为模板分子的情况。该文选取了最近4年发表在ACS、Elsevier、RSC等数据库约20篇相关文献,综述了片段/虚拟MIPs(FMIPs/DMIPs)的应用新进展。首先,针对蛋白质和微生物检测以及哺乳动物细胞印迹,介绍了FMIPs在生物医药领域的应用,另外介绍了FMIPs在食品分析领域的研究进展。随后,介绍了DMIPs在样品前处理和传感分析领域的应用。在样品前处理中,DMIPs主要作为固相萃取吸附剂进行装柱固相萃取、分散固相萃取、磁固相萃取、基质固相分散萃取等,或作为分子印迹膜材料,用于选择性萃取和富集分离样品中的目标分析物。在传感分析领域,DMIPs主要作为传感器的传感和转导元件,提高化学发光或荧光检测等方法的灵敏度和准确度。最后,对片段印迹和虚拟模板印迹策略的优缺点、区别与联系进行了总结,并展望了这两种策略的发展与应用前景。     

Recent Advances in Electrochemical Sensors Based on Molecularly Imprinted Polymers and Nanomaterials

This review focuses on the recent achievement during period of 2013–2018 related to the electrochemical sensors based on molecularly imprinted polymers (MIPs) combined with nanomaterials for various kinds of applications. MIPs based electrochemical sensors have found a great interest due to their high stability, short time required for electropolymerization, and high specificity towards the target analyte. The sensitivity is considered as one of the important parameter in electrochemical sensing strategies that should be improved by the combination of highly conductive nanomaterials with selective MIPs. In general, the most employed nanomaterials are magnetic nanoparticles, gold nanoparticles (AuNPs), carbon nanotubes and graphene. This review discusses the main current achievement as well as the current challenges regarding the development of biomimetic sensors in electroanalysis.     

Molecularly imprinted polymers-based sensors for bisphenol-A: Recent developments and applications in environmental,food and biomedical analysis

Bisphenol A (BPA) is a well-known endocrine-disrupting industrial compound that is found throughout many aspects of our daily life; from the water we drink and the food we eat to the babies’ bottles and children’s plastic toys. Chronic exposure to BPA may result in some severe medical issues which account for the great importance of its monitoring and removal from everyday products. The use of molecularly imprinted polymers (MIPs) for that purpose has acquired a lot of traction in recent decades. MIPs are artificial antibodies with selective recognition cavities for specifically targeted substances. They are created using a variety of synthetic methods and employed in numerous types of sensors to be used in a wide range of applications. In this review, we focus on the different production methods of MIPs and the varied types of electrochemical and optical sensors that employed MIPs to detect and analyze BPA. Finally, the broad variety of applications of MIPs in environmental, foodstuff, and biological samples are thoroughly examined. Future expected trends and prospective developments are also assessed.     

The rational development of molecularly imprinted polymer-based sensors for protein detection

The detection of specific proteins as biomarkers of disease, health status, environmental monitoring, food quality, control of fermenters and civil defence purposes means that biosensors for these targets will become increasingly more important. Among the technologies used for building specific recognition properties, molecularly imprinted polymers (MIPs) are attracting much attention. In this critical review we describe many methods used for imprinting recognition for protein targets in polymers and their incorporation with a number of transducer platforms with the aim of identifying the most promising approaches for the preparation of MIP-based protein sensors (277 references).     

分子印迹聚合物在极性农药残留检测中的应用进展

极性农药包括杀菌剂、除草剂、杀虫剂等,种类丰富,成本低廉,在农业中应用广泛,其滥用易导致水资源和土壤等环境污染,人类通过间接接触动植物源性食品和环境中的极性农药残留也增加了农药暴露风险。极性农药的物理化学性质差异大,通常痕量存在于食品和环境样品等复杂基质中,这对其准确检测分析带来了挑战。分子印迹聚合物(MIPs)作为一种人工制备的选择性吸附剂,具有与模板分子在空间结构、大小尺寸和功能基团上互补的特定识别位点,且易于制备,成本低,稳定性好,重复利用率高,已被广泛用于极性农药残留的样品前处理和分析检测中。MIPs可以作为固相萃取(SPE)、固相微萃取(SPME)、磁性固相萃取(MSPE)、搅拌棒固相萃取(SBSE)等前处理方法的吸附剂,还可用于制备光、电、化学传感器,作为质谱检测的离子源基底和拉曼光谱的增强基底。目前针对极性农药残留的检测,已有许多研究报道了多种分子印迹材料用于高效分离分析各种复杂基质中的极性农药残留,但未见此方面的综述报道。该文首先介绍了MIPs的印迹策略、聚合策略,并针对传统MIPs制备和应用中存在的问题,简要概括了一些新型的分子印迹策略和制备技术;然后从极性农药残留分析的角度出发,总结归纳了分子印迹材料近年来特别是近5年来在各种极性农药残留(包括新烟碱类、有机磷类、三嗪类、唑类、脲类等)检测中的应用,并针对现存问题展望了其未来的发展方向和趋势。     

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。     

Electrochemical Peptide-Based Sensors for Foodborne Pathogens Detection

Food safety and quality control pose serious issues to food industry and public health domains, in general, with direct effects on consumers. Any physical, chemical, or biological unexpected or unidentified food constituent may exhibit harmful effects on people and animals from mild to severe reactions. According to the World Health Organization (WHO), unsafe foodstuffs are especially dangerous for infants, young children, elderly, and chronic patients. It is imperative to continuously develop new technologies to detect foodborne pathogens and contaminants in order to aid the strengthening of healthcare and economic systems. In recent years, peptide-based sensors gained much attention in the field of food research as an alternative to immuno-, apta-, or DNA-based sensors. This review presents an overview of the electrochemical biosensors using peptides as molecular bio-recognition elements published mainly in the last decade, highlighting their possible application for rapid, non-destructive, and in situ analysis of food samples. Comparison with peptide-based optical and piezoelectrical sensors in terms of analytical performance is presented. Methods of foodstuffs pretreatment are also discussed.     

Molecularly Imprinted Polymers (MIPs) in Sensors for Environmental and Biomedical Applications: A Review

Molecular imprinted polymers are custom made materials with specific recognition sites for a target molecule. Their specificity and the variety of materials and physical shapes in which they can be fabricated make them ideal components for sensing platforms. Despite their excellent properties, MIP-based sensors have rarely left the academic laboratory environment. This work presents a comprehensive review of recent reports in the environmental and biomedical fields, with a focus on electrochemical and optical signaling mechanisms. The discussion aims to identify knowledge gaps that hinder the translation of MIP-based technology from research laboratories to commercialization.     

Selective Electrochemical Detection of Explosives with Nanomaterial Based Electrodes

Explosive detection technologies play a critical role in maintaining national security, remain an active research field with many devices and analytical/electroanalytical techniques. Analytical chemistry needs for homeland defense against terrorism make it clear that real-time and on-site detection of explosives and chemical warfare agents (CWAs) are in urgent demand. Thus, current detection techniques for explosives have to be improved in terms of sensitivity and selectivity, opening the way to electrochemical devices suitable to obtain the targeted analytical information in a simpler, cheaper and faster way. For the electrochemical determination of energetic substances, a large number of sensor electrodes have been presented in literature using different modification materials, especially displaying higher selectivity with molecularly imprinted polymers (MIPs). MIPs have already been utilized for the detection of hazardous materials due to their mechanical strength, flexibility, long-time storage and low cost. The sensitivity of MIP-based electrosensors can be enhanced by coupling with nanomaterials such as graphene oxide (GOx), carbon nanotubes (CNTs), or nanoparticles (NPs). Specific characteristics of involved nanomaterials, their modification, detection mechanism, and other analytical aspects are discussed in detail. Non-MIP electrosensors are generally functionalized with materials capable of charge transfer, H-bonding or electrostatic interactions with analytes for pre-concentration and electrocatalysis on their surface, whereas nanobio-electrosensors use analyte-selective aptamers having specific sequences of DNA, peptides or proteins to change the potential or current. This review intends to provide a combination of information related to MIPs and nanomaterial-based electrochemical sensors, limited to the most significant and illustrative work recently published.     

Electrochemical Biosensors in Food Safety: Challenges and Perspectives

Safety and quality are key issues for the food industry. Consequently, there is growing demand to preserve the food chain and products against substances toxic, harmful to human health, such as contaminants, allergens, toxins, or pathogens. For this reason, it is mandatory to develop highly sensitive, reliable, rapid, and cost-effective sensing systems/devices, such as electrochemical sensors/biosensors. Generally, conventional techniques are limited by long analyses, expensive and complex procedures, and skilled personnel. Therefore, developing performant electrochemical biosensors can significantly support the screening of food chains and products. Here, we report some of the recent developments in this area and analyze the contributions produced by electrochemical biosensors in food screening and their challenges.     

Molecularly Imprinted Electrochemical Sensors

In this review, the applications of molecularly imprinted polymer (MIP) materials in the area of electrochemical sensors have been explored. The designs of the MIPs containing different polymers, their preparation and their immobilization on the transducer surface have been discussed. Further, the employment of various transducers containing the MIPs based on different electrochemical techniques for determining analytes has been assessed. In addition, the general protocols for getting the electrochemical signal based on the binding ability of analyte with the MIPs have been given. The review ends with describing scope and limitations of the above electrochemical based MIP sensors.     

Molecularly imprinted polymer-carbon paste electrode (MIP-CPE)-based sensors for the sensitive detection of organic and inorganic environmental pollutants: A review

The rapidly growing existence of a number of contaminants (i.e. heavy metals, dye compounds, explosives and pesticides etc.) in environment is an alarming concern not only due to their harmful impacts for the environment bur also due to their potential high risk for human health. Thus, the careful and sensitive detection of these environmental contaminants is ver crucial. Electrochemical sensors combined with molecularly imprinted polymers (MIPs) become an attractive area for environmental monitoring. Benefiting from their great features such as high chemical and physical stability, cheap preparation process, excellent selectivity, sensitivity and fast response towards the target compound/s.This review paper aims to present and highlight the latest progresses in the design and development of novel electrochemical sensor systems composed of MIPs and carbon paste electrodes (CPEs) for the sensitive detection of pollutants in environmental samples.     

丝网印刷电极在食品安全检测中的应用进展

食品安全问题一直以来都是被广泛关注的热点,选择成本低、使用方便、灵敏度高的检测手段也就成为了食品安全检测领域中研究的焦点。丝网印刷电极因具有可批量生产、成本低、灵敏度高和一次性可抛等特点,已被广泛应用到食品安全检测中。因此,近年来,关于丝网印刷电极在食品安全检测中的应用研究日益增多,建立了多种类型的电化学传感器。依据电化学传感器的不同类型,综述了丝网印刷电极在食品安全检测中的应用,并对丝网印刷电极的应用前景进行了展望。     

Application of Molecularly Imprinted Polymers in the Analysis of Waters and Wastewaters

The increase of the global population and shortage of renewable water resources urges the development of possible remedies to improve the quality and reusability of waste and contaminated water supplies. Different water pollutants, such as heavy metals, dyes, pesticides, endocrine disrupting compounds (EDCs), and pharmaceuticals, are produced through continuous technical and industrial developments that are emerging with the increasing population. Molecularly imprinted polymers (MIPs) represent a class of synthetic receptors that can be produced from different types of polymerization reactions between a target template and functional monomer(s), having functional groups specifically interacting with the template; such interactions can be tailored according to the purpose of designing the polymer and based on the nature of the target compounds. The removal of the template using suitable knocking out agents renders a recognition cavity that can specifically rebind to the target template which is the main mechanism of the applicability of MIPs in electrochemical sensors and as solid phase extraction sorbents. MIPs have unique properties in terms of stability, selectivity, and resistance to acids and bases besides being of low cost and simple to prepare; thus, they are excellent materials to be used for water analysis. The current review represents the different applications of MIPs in the past five years for the detection of different classes of water and wastewater contaminants and possible approaches for future applications.     

‘Gate effect’ in molecularly imprinted polymers: the current state of understanding

The so-called ‘gate effect’ is frequently used in electrochemical signal transduction for chemosensing developed using recognition units based on molecularly imprinted polymers (MIPs). A vast majority of different reported MIP electroanalytical systems makes the gate effect definition difficult to be established precisely, thus resulting in ambiguity and complexity. In the MIP literature, the gate effect is predominantly considered as an electrode–electrolyte phenomenon, which depends on the MIP film nature. However, most of the reports do not describe or confirm the origin of this effect. The present review critically evaluates representative original articles on the subject to increase understanding the origin of the gate effect operation in MIP-based electrochemical chemosensors.     

分子印迹表面等离子共振传感器在食品安全检测中的最新研究进展

分子印迹聚合物具有空间结构选择性高、稳定性好和制备过程简单等特点,结合表面等离子共振传感器,可用于分子间相互作用和结合特性的研究。随着石墨烯、量子点等纳米材料的出现和广泛应用,基于分子印迹技术的表面等离子共振传感器的灵敏度获得了改善,促进了该技术在食品安全检测领域的快速发展。该文基于分子印迹技术简要介绍了表面等离子共振传感器芯片的制备技术、分析体系及其优点,重点分析了国内外将分子印迹-表面等离子共振传感器用于食品安全检测的最新研究成果,阐释了分子印迹-表面等离子共振技术的优势,并展望了该技术在食品安全分析领域的发展趋势。     

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.