A molecularly imprinted polymer based chemiluminescence array sensor for one‐step determination of phenothiazines and benzodiazepines in pig urine

The residues of phenothiazines and benzodiazepines in foods of animal origin are dangerous to consumers. For inspection of their abuses, this study for the first time reported on the use of a chemiluminescence array sensor for the simultaneous determination of four phenothiazines and five benzodiazepines in pig urine. Two molecularly imprinted polymers were coated in different wells of a conventional 96‐well microtiter plate as the recognition reagents. After sample loading, the absorbed analytes were initiated directly by using an imidazole enhanced bis(2,4,6‐trichlorophenyl)oxalate–hydrogen peroxide system to emit light. The assay process consisted of only one sample‐loading step prior to data acquisition, so one test was finished within 10 min. The limits of detection for the nine drugs in the pig urine were in a range of 0.1 to 0.6 pg/mL, and the recoveries from the fortified blank urine samples were in a range of 80.3 to 95%. Furthermore, the sensor could be reused six times. Therefore, this sensor could be used as a simple, rapid, sensitive and reusable tool for routine screening for residues of phenothiazines and benzodiazepines in pig urine.     

Development of a quantum dot molecularly imprinted polymer sensor for fluorescence detection of atrazine

Atrazine is a common agricultural pesticide which has been reported to occur widely in surface drinking water, making it an environmental pollutant of concern. In the quest for developing sensitive detection methods for pesticides, the use of quantum dots (QDs) as sensitive fluorescence probes has gained momentum in recent years. QDs have attractive and unique optical properties whilst coupling of QDs to molecularly imprinted polymers (MIPs) has been shown to offer excellent selectivity. Thus, the development of QD@MIPs based fluorescence sensors could provide an alternative for monitoring herbicides like atrazine in water. In this work, highly fluorescent CdSeTe/ZnS QDs were fabricated using the conventional organometallic synthesis approach and were then encapsulated with MIPs. The CdSeTe/ZnS@MIP sensor was characterized and applied for selective detection of atrazine. The sensor showed a fast response time (5 min) upon interaction with atrazine and the fluorescence intensity was linearly quenched within the 2–20 mol L^?1 atrazine range. The detection limit of 0.80 × 10^?7 mol L^?1 is comparable to reported environmental levels. Lastly, the sensor was applied in real water samples and showed satisfactory recoveries (92–118%) in spiked samples, hence it is a promising candidate for use in water monitoring.     

A microtitre chemiluminescence sensor for detection of pyrethroids based on dual‐dummy‐template molecularly imprinted polymer and computational simulation

The residues of pyrethroids in foods of animal origin are dangerous to the consumers, so this study presented a chemiluminescence sensor for determination of pyrethroids in chicken samples. A dual‐dummy‐template molecularly imprinted polymer capable of recognizing 10 pyrethroids was synthesized. The results of computation simulation showed that the specific 3D conformations of the templates had important influences on the polymer' recognition ability. The polymer was used to prepare a sensor on conventional 96‐well microplates, and the sample solution was added into the wells for direct absorption. The absorbed analytes were initiated with the bis(2,4,6‐trichlorophenyl)oxalate–H₂O₂–imidazole system, and the chemiluminescence intensity was used for analyte quantification. Results showed that one assay was finished within 12 min, and this sensor could be reused four times. The limits of detection for the 10 analytes were in the range o0.3–6.0 pg/ml, and the recoveries from the standards of fortified blank chicken samples were in the range 70.5–99.7%.     

A selective molecularly imprinted polymer‐carbon nanotube sensor for cotinine sensing

Conductive composite films comprised of single‐walled carbon nanotubes coated with molecularly imprinted poly‐4‐vinylphenol are produced and characterized using ultraviolet and infrared spectroscopies, confirming the successful molecular imprinting of the film with cotinine. The electrical resistance of the imprinted film changes significantly upon binding cotinine, by more than 30 kΩ, while the unimprinted film in comparison elicits little response. Additionally, once the cotinine template desorbs from the film, the resistance of the imprinted film returns to a value close to the pre‐adsorption baseline. Scanning electron microscopy is used to study the morphology of the film compared with the unimprinted control, and gas chromatography quantitatively confirms that the imprinted film selectively detects cotinine while discriminating against the structurally similar alkaloid, nicotine. Copyright © 2013 John Wiley & Sons, Ltd.     

Mechanisms underlying molecularly imprinted polymer molecular memory and the role of crosslinker: resolving debate on the nature of template recognition in phenylalanine anilide imprinted polymers

A series of molecular dynamics simulations of prepolymerization mixtures for phenylalanine anilide imprinted co-(ethylene glycol dimethacrylate-methacrylic acid) molecularly imprinted polymers have been employed to investigate the mechanistic basis for template selective recognition in these systems. This has provided new insights on the mechanisms underlying template recognition, in particular the significant role played by the crosslinking agent. Importantly, the study supports the occurrence of template self-association events that allows us to resolve debate between the two previously proposed models used to explain this system's underlying recognition mechanisms. Moreover, the complexity of the molecular level events underlying template complexation is highlighted by this study, a factor that should be considered in rational molecularly imprinted polymer design, especially with respect to recognition site heterogeneity.     

HPLC-based bioseparations using molecularly imprinted polymers

HPLC-based separations of amino acids and peptides, nucleotide bases, drugs, sugars and steroids using molecularly imprinted polymers (MIPs) have been reviewed in this article. The molecular recognition mechanisms of the template molecules on the MIPs in organic and aqueous eluents were discussed. Furthermore, new polymerization methods suitable for preparations of HPLC columns and packing materials using molecular imprinting techniques, and their applications to HPLC-based separations are also dealt with.     

A rapid and economical sample pretreatment method using molecularly imprinted polymers for bioavailable content analyses of oxytetracycline in soils

Abstract

In order to analyze the bioavailable oxytetracycline (OTC) contents of soils, a new high-efficiency and economical pretreatment method was established using a molecularly imprinted polymer (MIP) with high affinity and specific selectivity for OTC synthesized by bulk polymerization. For comparison, an Oasis HLB solid phase extraction (SPE) method was used to measure the total extractable OTC content of soils. The resulting OTC recoveries from the spiked soil solutions using the MIP method ranged from 80.78±.26% to 93.75?±?6.79%, with an average of 86.00?±?2.13%, and a relative standard deviation of 2.48% (n= 5), when OTC concentrations in spiked soil solutions varied from 0.5 to 100.0?μg L^?1. When OTC contents in spiked soils varied from 1.0 to 500.0?μg kg^?1 and soils were aged for three weeks, OTC recoveries from spiked soils with the Oasis HLB SPE method ranged from 78.16?±?3.72% to 96.67?±?1.62% (n= 3), while those with the MIP method ranged from 57.43?±?3.48% to 76.34?±?1.30% (n= 3). Analyses of OTC contents in five soil samples indicated that bioavailable OTC contents were only 1.35%–5.87% of the total soil OTC contents. Data from the new method were more valuable than the Oasis HLB SPE method on OTC pollution intensity assessment, potential ecological, and environmental risks evaluation.     

Molecular imprinting science and technology: a survey of the literature for the years up to and including 2003

Over 1450 references to original papers, reviews and monographs have herein been collected to document the development of molecular imprinting science and technology from the serendipitous discovery of Polyakov in 1931 to recent attempts to implement and understand the principles underlying the technique and its use in a range of application areas. In the presentation of the assembled references, a section presenting reviews and monographs covering the area is followed by papers dealing with fundamental aspects of molecular imprinting and the development of novel polymer formats. Thereafter, literature describing attempts to apply these polymeric materials to a range of application areas is presented.     

Preparation of bovine hemoglobin surface molecularly imprinted cotton for selective protein recognition

We have developed a bovine hemoglobin (BHb) surface molecularly imprinted cotton based on degreasing cotton via surface imprinting technique for the efficient selective adsorption of BHb. The morphological structure of the samples was characterized by Scanning Electron Microscopy (SEM), and the chemical modification steps were characterized by Fourier Transform Infrared Spectroscopy (FTIR). The maximum adsorption capacity of the molecularly imprinted cotton (MIC) and non-imprinted cotton (NIC) for BHb was 62.95 mg/g and 8.32 mg/g, respectively, at the optimum pH value of 6.2. The kinetics studies demonstrated that the adsorption follows a pseudo-first-order kinetic model. The adsorption isotherm analysis indicated that the Langmuir adsorption isotherm fits well with the adsorption equilibrium data. Also, the selective adsorption shows the MIC has a good selectivity for BHb. In addition, the assessment of the reusability of the MIC was tested for five successive cycles revealed no significant decrease of the adsorption capacity. Electrophoretic analysis suggests the MIC were successfully applied to capture template proteins from the bovine blood sample.     

Molecularly imprinted polyaniline molecular receptor–based chemical sensor for the electrochemical determination of melamine

Molecularly imprinted polymer‐modified glassy carbon electrode (GCE)‐based electrochemical sensor is prepared using the electropolymerization of aniline in the presence of melamine (MA) as a template. In this work, the advantages of molecularly imprinted conducting polymers (MICPs) and electroanalytical methods were combined to obtain an electronic device with better performances. The sensor performance was evaluated by cyclic voltammetry (CV) and square wave voltammetry (SWV) with the linear range of 0.6‐16 × 10^?9M, quantification limit of 14.9 × 10^?10M, and detection limit of 4.47 × 10^?10M (S/N = 3). The selectivity of the sensor was tested in the presence of acetoguanamine (AGA), diaminomethylatrazine (DMT), casein, histidine, and glycine interfering molecules taken at the triple concentration with MA that demonstrated too small current response compared with that of the analyte indicating high specificity of the sensor towards the template. The sensor was successfully applied to determine MA in infant formula samples with significant recovery greater than 96% and relative standard deviation (RSD) less than 4.8%. Moreover, the good repeatability, recyclability, and stability make this sensor device promising for the real‐time monitoring of MA in different food stuffs.     

Molecularly imprinted polymer with salicylaldehyde-Cu(OAc)2 as template

In the report molecularly imprinted polymer (MIP) with salicylaldehyde-Cu(OAc)(2) as the template was synthesized and characterized by SEM, porosity and elemental analysis. Copper acetate was introduced since salicylaldehyde alone cannot display imprinting effect for its intramolecular hydrogen bond. The strong coordination interaction between salicylaldehyde and copper acetate made the complex have high retention on the HPLC column based on the SAD-Cu(OAc)(2) imprinted polymer. Several structural analogues such as salicylaldoxime, sulfosalicylic acid, p-hydroxybenzaldehyde and their complexes with copper acetate were chosen to study the selectivity of the MIPs. The influence of acetic acid and H(2)O in methanol mobile phase was studied. The experimental results showed that small amount of either acetic acid or H(2)O in mobile phase would weaken the interaction between the complex and the polymer, therefore, the retention of the complex was lowered to a large extent, but that of salicylaldehyde remained almost unchanged. The polymer imprinted with the complex showed high selectivity to both the acetate and copper (II). In addition, the MIP showed an enhanced selectivity to its template compared with the polymer prepared without copper acetate.     

Molecular imprinting science and technology: a survey of the literature for the years 2004–2011

Herein, we present a survey of the literature covering the development of molecular imprinting science and technology over the years 2004–2011. In total, 3779 references to the original papers, reviews, edited volumes and monographs from this period are included, along with recently identified uncited materials from prior to 2004, which were omitted in the first instalment of this series covering the years 1930–2003. In the presentation of the assembled references, a section presenting reviews and monographs covering the area is followed by sections describing fundamental aspects of molecular imprinting including the development of novel polymer formats. Thereafter, literature describing efforts to apply these polymeric materials to a range of application areas is presented. Current trends and areas of rapid development are discussed. Copyright © 2014 John Wiley & Sons, Ltd.     

A sensitive fluorescent nanosensor for chloramphenicol based on molecularly imprinted polymer‐capped CdTe quantum dots

A novel fluorescent nanosensor using molecularly imprinted silica nanospheres embedded CdTe quantum dots (CdTe@SiO₂@MIP) was developed for detection and quantification of chloramphenicol (CAP). The imprinted sensor was prepared by synthesis of molecularly imprinting polymer (MIP) on the hydrophilic CdTe quantum dots via reverse microemulsion method using small amounts of solvents. The resulting CdTe@SiO₂@MIP nanoparticles were characterized by fluorescence, UV–vis absorption and FT‐IR spectroscopy and transmission electron microscopy. They preserved 48% of fluorescence quantum yield of the parent quantum dots. CAP remarkably quenched the fluorescence of prepared CdTe@SiO₂@MIP, probably via electron transfer mechanism. Under the optimal conditions, the relative fluorescence intensity of CdTe@SiO₂@MIP decreased with increasing CAP by a Stern–Volmer type equation in the concentration range of 40–500 µg L^–1. The corresponding detection limit was 5.0 µg L^–1. The intra‐day and inter‐day values for the precision of the proposed method were all <4%. The developed sensor had a good selectivity and was applied to determine CAP in spiked human and bovine serum and milk samples with satisfactory results. Copyright © 2015 John Wiley & Sons, Ltd.     

Preparation and evaluation of a molecularly imprinted polymer for the selective recognition of testosterone--application to molecularly imprinted sorbent assays

Biomimetic testosterone receptors were synthesized via molecular imprinting for use as antibody mimics in immunoassays. As evaluated by radioligand binding assays, imprinted polymers prepared in acetonitrile were very specific for testosterone because the nonimprinted control polymers bound virtually no radiolabeled testosterone. The polymers present an appreciable affinity, with association constants of K(a) = 3.3 x 10(7) M(- 1) (high-affinity binding sites). The binding characteristics of the polymers were also evaluated in aqueous environment to study their viabilities as alternatives to antibodies in molecularly imprinted sorbent assays. Compared with the testosterone-specific antibodies present in commercial kits, our molecularly imprinted polymers are somewhat less sensitive but show a high selectivity.     

分子印迹技术应用于血清中地高辛的快速检测

应用分子印迹的方法制备对地高辛有特异性吸附性能的印迹聚合物颗粒,再将颗粒与琼脂糖混合并固定于玻碳电极上制备成地高辛分子印迹聚合膜传感器,传感器可以特异性地结合模板分子地高辛且其电化学信号与模板浓度相关,再用它来检测血清中地高辛的含量。结果表明:分子印迹传感器具有制作简便、成本低、检测快速、特异性高、稳定性好等优点,检测下限为1.28 nmol/L,检测时间为5 min。     

A molecularly imprinted nanofilm‐based quartz crystal microbalance sensor for the real‐time detection of pirimicarb

This study aimed to prepare a novel quartz crystal microbalance (QCM) sensor for the detection of pirimicarb. Pirimicarb‐imprinted poly (ethylene glycol dimethacrylate‐N‐metacryloyl‐(l )‐tryptophan methyl ester) [p (EGDMA‐MATrp)] nanofilm (MIP) on the gold surface of a QCM chip was synthesized using the molecular imprinting technique. A nonimprinted p (EGDMA‐MATrp) nanofilm (NIP) was also synthesized using the same experimental technique. The MIP and NIP nanofilms were characterized via Fourier transform infrared spectroscopy attenuated total reflectance spectroscopy, contact angle, atomic force microscopy, and an ellipsometer. A competitive adsorption experiment on the sensor was performed to display the selectivity of the nanofilm. An analysis of the QCM sensor showed that the MIP nanofilm exhibited high sensitivity and selectivity for pirimicarb determination. A liquid chromatography‐tandem mass spectrometry method was prepared and validated to determine the accuracy and precision of the QCM sensor. The accuracy and precision of both methods were determined by a comparison of six replicates at three different concentrations to tomato samples extracted by using a Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method. The limit of detection of the QCM sensor was found to be 0.028 nM. In conclusion, the QCM sensor showed good accuracy, with recovery percentages between 91 and 94%. Also, the pirimicarb‐imprinted QCM sensor exhibited a fast response time, reusability, high selectivity and sensitivity, and a low limit of detection. Therefore, it offers a serious alternative to the traditional analytical methods for pesticide detection in both natural sources and aqueous solutions.     

Removal of the fermentation by-product succinyl L-tyrosine from the beta-lactamase inhibitor clavulanic acid using a molecularly imprinted polymer

Clavulanic acid is a beta-lactamase inhibitor used in therapeutic combinations with the penicillin-type antibiotics. During the fermentation leading to clavulanic acid, a succinyl L-tyrosine by-product is unavoidably formed. Occasionally, the amount of this by-product is found to be as high as 2% of the product even after standard purification operations. To further remove this impurity, we prepared a highly specific adsorbent for succinyl L-tyrosine with the molecular imprinting technique. This was performed by simultaneously using vinylbenzyl trimethylammonium chloride and methacrylic acid as the functional monomers. The imprinted polymer selectively bound succinyl L-tyrosine, and could be successfully used to remove this impurity at concentrations of less than 2% in the presence of clavulanic acid.     

A selective molecularly imprinted polymer for immobilization of acetylcholinesterase (AChE): an active enzyme targeted and efficient method

In the present study, we immobilized acetylcholinesterase (AChE) enzyme onto acetylcholine removed imprinted polymer and acetylcholine containing polymer. First, the polymers were produced with acetylcholine, substrate of AChE, by dispersion polymerization. Then, the enzyme was immobilized onto the polymers by using two different methods: In the first method (method A), acetylcholine was removed from the polymer, and then AChE was immobilized onto this polymer (acetylcholine removed imprinted polymer). In the second method (method B), AChE was immobilized onto acetylcholine containing polymer by affinity. In method A, enzyme‐specific species (binding sites) occurred by removing acetylcholine from the polymer. The immobilized AChE reached 240% relative specific activity comparison with free AChE because the active enzyme molecules bounded onto the polymer. Transmission electron microscopy results were taken before and after immobilization of AChE for the assessment of morphological structure of polymer. Also, the experiments, which include optimum temperature (25–65°C), optimum pH (3–10), thermal stability (4–70°C), kinetic parameters, operational stability and reusability, were performed to determine the characteristic of the immobilized AChE. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis and evaluation of uniformly sized nalidixic acid-imprinted nanospheres based on precipitation polymerization method for analytical and biomedical applications

For the first time in this work, uniform molecularly imprinted polymer (MIP) nanoparticles were prepared using nalidixic acid as a template. The MIP nanoparticles were successfully synthesized by precipitation polymerization applying methacrylic acid (MAA) as a functional monomer and trimethylolpropane trimethacrylate (TRIM) as a cross-linking monomer at different mole ratios. The morphology, binding, recognition, selectivity, and in vitro release behaviors of obtained particles were studied. The produced polymers were characterized by Fourier transform infrared spectroscopy and differential scanning calorimetric. Furthermore, their morphology was analyzed accurately by scanning electron microscopy, photon correlation spectroscopy, and Brunauer-Emmett-Teller analysis. The nanospheres and microspheres with mean diameter values of 94 nm, 256 nm, and 1.2 μm were obtained using nalidixic acid-MAA-TRIM various mole ratios. Among the MIPs, the product with nalidixic acid-MAA-TRIM mole ratio of 1:12:12 established nanospheres with the lowest polydispersity index (0.003), an average pore diameter (12 nm), and the highest specific surface area (280 m(2) g(-1)) and selectivity factor (10.4). Results from binding experiments demonstrated that the imprinted nanospheres with a 94-nm mean diameter and a binding capacity of 28 mg of nalidixic acid per gram of polymer had higher specific affinity to nalidixic acid in contrast with the other imprinted nanospheres, microspheres, and nonimprinted particles. However, the binding performance of imprinted nanospheres in human serum was estimated using high-performance liquid chromatography analysis (binding approximately 98% of nalidixic acid). In addition, release experiments proved to be successful in the controlled release of nalidixic acid during a long period. The 20% of loaded nalidixic acid was released from the imprinted nanospheres within the first 20 h, whereas the remaining 80% was released in the after 120 h. The nalidixic acid release kinetics from the MIPs was highly affected by properties of the particles.     

Molecularly imprinted hollow sphere array for the sensing of proteins

Mono‐dispersed molecularly imprinted hollow spheres (MIHSs) for hemoglobin (Hb) were prepared by employing silica nanospheres as the sacrificial templates. The obtained hollow spheres with uniform particle size of 360 nm in diameter were characterized by transmission electron microscopy. The outstanding affinities of these MIHSs to the target protein were confirmed by adsorption experiment in aqueous solution. Adsorption equilibrium was achieved within 10 min while the binding capacity (Q_max) of Hb was 8.84 µmol g^–1 at pH7.0. Furthermore, the MIHSs were successfully assembled into a closely‐packed 3D colloidal array. The molecularly imprinted hollow sphere array (MIHSA) can selectively recognize Hb. As the concentration of Hb increased, the structure color of the MIHSA changed from blue to green, and turn to white finally with maximum red shift for 43 nm. The MIHSA showed promising potential for the naked‐eye detection of target Hb.

Reflection spectra of the MIHSA in response to different Hb concentrations (0.075–15 µmol L^–1)