Non-imprinted Polymer Research Articles

An Ultra-Sensitive Molecularly Imprinted Poly(Aniline) Based Electrochemical Sensor for the Determination of Bisphenol A in Synthetic Human Serum Specimen and Plastic Bottled Water Samples

We explain the development of an ultra-sensitive molecularly imprinted polymer-based electrochemical sensor for rapid and selective determination of bisphenol A (BPA) in human serum and water samples. Electropolymerization of functional monomer aniline was performed in the presence of BPA by cyclic voltammetry (CV) to prepare a molecularly imprinted poly(aniline) based GCE sensor (MIP(ANI)/GCE). The developed MIP surface was characterized using Fourier-transform infrared spectroscopy, Raman spectrometry, scanning electron microscopy, contact angle measurements, CV, and electrochemical impedance spectroscopy. The MIP(ANI)/GCE sensor showed a highly sensitive performance with a linear range of 1.0 and 8.0 × 10−15 M. The limit of detection (LOD) and limit of quantification (LOQ) values were 0.193 and 0.643 fM, respectively. The applicability of the MIP(ANI)/GCE was assessed by applying it to human serum and plastic bottled water samples. The LOD and LOQ values were calculated as 0.257 and 0.856 fM for the serum sample. Imprinting factor and interference studies were also carried out using similarly structured compounds and the most common interfering agents showing the selectivity of the MIP(ANI)/GCE sensor. Finally, the non-imprinted polymer (NIP)-based sensor was prepared to control the MIP(ANI)/GCE performance.

Synthesis of Molecularly Imprinted Polymer Nanoparticles for Removal of Sudan III Dye

Molecularly imprinted polymer (MIP) nanoparticles of Sudan III dye as template were synthesized by using non-covalent approach. The molecularly imprinted polymers were synthesized in a microemulsion contained Sudan III as a template, acrylic acid (AA) as a monomer, 1,4-butanediol dimethacrylate as a cross-linker and 2,2-azo-bisisobutyronitrile (AIBN) as an initiator. The synthesized beads were characterized by TEM and FTIR. The TEM results revealed the nanosize beads of polymers were produced. The efficiency of imprinted and non-imprinted polymers was evaluated by batch binding studies. The results showed that the MIP 3 (0.1: 6: 10, Sudan III: AA: 1,4-butanediol dimethacrylate) was best among all polymers with highest rebinding efficiency. The removal efficiency of selected MIP 3 in the spiked Sudan III dye river water sample was about 80%. This study was conducted to produce nanosized molecularly imprinted polymers by using microemulsion polymerization technique.

Determination of preservatives in liquids by piezosensors

In the current study, piezosensors based on the molecularly imprinted polyimides with imprints of potassium sorbate and sodium benzoate were obtained. Molecularly Imprinted Polymers (MIPs) were synthesized using a polyimide and a non-covalent imprinting technique. It was established that the use of 0.1 g/mL template concentration at the thermochemical stage led to the formation of the maximum number of molecular imprints on the film surface. Using the scanning force microscopy, it was found that the reference polymer film had a uniform surface with a small height difference from 1.4 to 2.6 nm (including 88.94 % of pores with a radius of up to 10 nm) and had good film thickness reproducibility. The surface morphology of films of molecularly imprinted polymers with imprints of potassium sorbate and sodium benzoate had more developed surface, which was associated with the peculiarities of the formation of imprints. In this work, imprinting factor (IF) and selectivity coefficient (k) of the sensor were calculated. Molecularly imprinted polymers had better selectivity, sensitivity, and ability to recognize target template molecules than the reference polymers (non-imprinted polymers). Molecularly imprinted polymer-modified piezoelectric sensors (MIP sensors) have been used to analyze potassium sorbate and sodium benzoate in non-alcoholic drinks. The linear concentration range was identified to be 5 - 500 mg/L and the limit of detection for potassium sorbate and sodium benzoate were 1.6 mg/L and 2 mg/L, respectively. The determination of potassium sorbate and sodium benzoate in non-alcoholic drinks was carried out by MIP sensors and spectrophotometry method. The results obtained by the sensors and the spectrophotometry method were in good agreement. The concentration of preservatives for the potassium sorbate and the sodium benzoate in non-alcoholic drinks was 130 - 176 mg/L and 129 - 146 mg/L, respectively.

Extraction of Catechin as a Flavonoid Compound via Molecularly Imprinted Polymers

The aim of this study is synthesis of molecularly imprinted polymers (MIPs) and evaluation for extraction of catechin. Catechin is a bioactive compound which is found abundantly in green tea. In this paper, MIPs was synthesized by precipitation polymerization technique for catechin, acrylic acid and trimethylolpropane trimethacrylate as a template, functional monomer and cross-linker in a molecular ratio of (1:12:12), respectively. Surface morphology in the MIPs by scanning electron microscopy (SEM) demonstrated spheres with nanometric scale. Fourier transform infrared spectroscopy (FTIR) of the polymers showed that catechin molecule was captured in the network copolymers. Porosity of the polymers were analyzed using Brouneur Emmet Teller (BET) technique. Based on BET analysis, specific surface area of the MIPs was 45.5 m2.g-1 while it was 42.2 m2.g-1 for non-imprinted polymers (NIPs). It means that the imprinting process was carried out successfully. Adsorption properties of the polymers were characterized too. The best binding capacity of the MIPs was reported equal to 440 mg. g-1 in 750 ppm of the feed concentration whereas it was 84mg.g-1 for quercetin (similar structure of catechin). It confirms that the MIPs technology can be introduced as a good candidate for separation process with a satisfactory result in selectivity. The binding capacity of the MIPs was evaluated for natural extract of green tea using a high-performance liquid chromatography (HPLC) device which similar results were obtained. According to above mentioned results, separation and pre-concentration of the bioactive compounds from the extract of medicinal plants can be suggested via MIPs technique.

QCM-based assay designs for human serum albumin

Solid-phase synthesis is an elegant way to create molecularly imprinted polymer nanoparticles (nano-MIPs) comprising a single binding site, i.e. mimics of antibodies. When using human serum albumin (HSA) as the template, one achieves nano-MIPs with 53 ± 19 nm diameter, while non-imprinted polymer nanoparticles (nano-NIPs) reach 191 ± 96 nm. Fluorescence assays lead to Stern–Volmer plots revealing selective binding to HSA with selectivity factors of 1.2 compared to bovine serum albumin (BSA), 1.9 for lysozyme, and 4.1 for pepsin. Direct quartz crystal microbalance (QCM) assays confirm these results: nano-MIPs bind to HSA immobilized on QCM surfaces. This opens the way for competitive QCM-based assays for HSA: adding HSA to nanoparticle solutions indeed reduces binding to the QCM surfaces in a concentration-dependent manner. They achieve a limit of detection (LoD) of 80 nM and a limit of quantification (LoQ) of 244 nM. Furthermore, the assay shows recovery rates around 100% for HSA even in the presence of competing analytes.

Development of conductive molecularly imprinted polymers (cMIPs) for limonene to improve and interconnect QCM and chemiresistor sensing

This paper presents a straightforward method to develop a chemiresistor based sensor for the detection of the plant volatile R-(+)-limonene. By using blends of polystyrene-based molecularly imprinted polymers (MIPs) and the organic semiconductor poly3-hexylthiophene (P3HT), electrical conductivity is introduced into the highly selective MIPs, allowing their application as sensing layers in robust and economic chemiresistor devices. Polystyrene-based MIPs and conductive blends were assessed on quartz crystal microbalances (QCMs) and chemiresistors and compared to non-imprinted polymer (NIP) and pristine P3HT layers. Blending MIPs and conductive polymers led to a strong signal enhancement, both on the QCM as well as during resistive measurements, allowing for detecting R-(+)-limonene gas concentrations as low as 50 ppm. The presented results provide a simple and valuable way for potential MIP sensing improvements and the possibility for a method transfer to cheap and simple chemiresistors.

Influence of the synthesis parameters on the efficiency of fluorescent ion-imprinted polymers for lead detection

New fluorescent ion-imprinted polymers (IIPs) specific for Pb(II) detection were synthesized by precipitation polymerization. The fluorescent activity of the IIPs was provided by a fluorescent functional monomer, ANQ-ST, based on the chelating 5-amino-8-hydroxyquinoline moiety coupled to anthracene and a styrenic group. Various synthesis parameters were tested: metal/functional monomer ratio, polymerization solvent and crosslinker (ethyleneglycol dimethacrylate, EGDMA, or divinylbenzene, DVB). The characterization of the different IIPs was carried out by solid-state 13C NMR spectroscopy, to analyse the structure of the polymers and to attest the integration of the ANQ-ST in the polymer matrix, and by scanning electron microscopy and nitrogen adsorption/desorption experiments, to study the morphology of the prepared materials. After characterization, the IIPs and their corresponding non-imprinted polymer (NIPs) were subjected to various fluorescence studies, in order to conclude on the influence of the synthesis parameters onto the polymer properties. The results demonstrated that the IIP synthesized with a metal/functional monomer ratio of 0.42 in DMSO/MeOH (1:1, v/v) and using EGDMA as a crosslinker was very sensitive to the presence of Pb(II) ions and almost not to other tested ions (Ag(I), Na(I), Ca(II), Cd(II), Co(II), Cu(II) and Zn(II)), even introduced in high excess. Calibration curves were performed in various matrices: ultra-pure water, buffered water at pH 7.0 and 8.1, seawater, tap water. They highlighted the low impact of the tested matrices onto the detection and allowed to determine a limit of detection of 2.4 μg/L and a linear range of 8.0–50 μg/L. Finally, the very good recovery obtained in natural samples emphasized the potential for the synthesized IIP to detect Pb(II) in natural waters.

Fabrication and characterization of magnetic molecularly imprinted polymer based on deep eutectic solvent for specific recognition and quantification of vanillin in infant complementary food

A magnetic molecularly imprinted polymer based on deep eutectic solvent was synthesized for specific identification and quantification of vanillin. Fe3O4@SiO2-CC and deep eutectic solvent were applied as the carrier of magnetic material and functional monomer, respectively. According to composition and morphology characterizations and adsorption kinetics, the imprinted polymer had excellent advantages on adsorption capacity and identification specificity for vanillin compared with non-imprinted polymer, while its reusability still remained stable. According to the high-performance liquid chromatography, the detection method based on imprinted polymer produced satisfactory analytical results. The limit of quantification was 0.2 μg·mL−1. The mean spiked recoveries for vanillin ranged from 91.2% to 100.2% with intra- and inter-day precision were both less than 7.2%. Compared to traditional extraction methods, this method presented best adsorption and extraction performances. In summary, the method could be further applied to the specific separation and quantification of vanillin in infant complementary food.

Development and Application of Molecularly Imprinted Polymers for the Selective Extraction of Chlordecone from Bovine Serum

The widespread use of chlordecone (CLD), an organochlorine pesticide, until the 1990s to protect banana crops in the French West Indies led to significant pollution of water and soil and, subsequently, of bovine intended for human consumption. Carcasses are submitted to official controls based on perirenal fat CLD determination. In order to allow for pre-slaughter controls, a selective analytical method based on a molecularly imprinted polymer (MIP) associated to the LC/MS-MS method was developed to determine the level of CLD in bovine serum that can be collected before slaughter. Different synthesis conditions were therefore assayed by varying the nature of the monomer and of the porogen, and the most promising MIP in terms of selective retention for CLD (extraction recovery close to 100%) was completely characterized by solid-phase extraction (repeatability of the extraction procedure, of the synthesis, and of the cartridge filling) in pure medium. The capacity of the MIP was determined at 0.13 µmol g−1 of MIP. After application of a spiked bovine serum sample on the MIP, the selective retention was maintained (87 and 21%, respectively, on the MIP and on the corresponding non-imprinted polymer). Moreover, extraction on the MIP led to a cleaner extract compared to those issued from a conventional C18 sorbent.

A Fluorimetric Method Based On Magnetic Molecularly Imprinted Polymer For Selective Detection Of Chlorferon

In the present work, reusable magnetic molecularly imprinted polymers have been used for the first time as an adsorbent for the determination of chlorferon. Magnetic molecularly imprinted polymers have been used for the selective separation of chlorferon from the solution and sensitive fluorimetric determination has been performed using the native fluorescence of chlorferon. The developed method is rapid and determination of chlorferon was completed in an hour. Limit of detection (LOD) of the method was found to be 0.0027 µM and the linearity of the calibration graph was observed within the range of 0.01-0.36 µM (2.5 - 75 µg L-1). Adsorption isotherms point out the multilayer adsorption and the heterogeneous distribution of binding sites for imprinted polymer and homogeneous binding site for non-imprinted polymer. The adsorption capacities of imprinted polymer and non-imprinted polymer were calculated as 2.03 μmol g-1 and 0.96 μmol g-1, respectively and the imprinting factor was found to be 2.11. The interference effects of some organic compounds and characterization studies were also evaluated. The method has been applied to honey and tap water samples and the recoveries were found to be in the range of 91.3 and 101.1 %.

Selective recognition and determination of malachite green in fish muscles via surface-enhanced Raman scattering coupled with molecularly imprinted polymers

Molecularly imprinted polymers (MIPs) were incorporated with surface-enhanced Raman scattering (SERS) for selective recognition and rapid detection of malachite green in fish muscles. Among four functional monomers, methacrylic acid was selected as the suitable one for MIPs synthesis based upon computational simulation. The optimized MIP exhibited a higher adsorption efficiency for malachite green than that of nonimprinted polymers. The 74 nm gold-silver core-shell nanoparticles (Au@Ag NPs) provided stronger SERS signals for malachite green than those of other eleven gold nanoparticles and Au@Ag NPs. The use of selected MIP with Au@Ag NPs enabled to detect as low as 0.5–1 ng/g of malachite green in fish muscles from three different species, which was similar to that of 0.5 μg/L for malachite green standard solutions. The limit of detection was 0.37–0.64 ng/g in different fish muscles. This study provided a rapid, selective, and sensitive approach for SERS analysis of malachite green in aquatic products. • Surface-enhanced Raman scattering (SERS) used for malachite green (MG) detection. • Molecularly imprinted polymers (MIPs) designed to capture MG via computer simulation. • From 12 metallic colloid, Au@Ag (dia. 74 nm, seed 43 nm) chosen as a SERS substrate. • As low as 0.5–1 ppb MG in fish muscles detected with MIP-SERS hybrid method. • Interference of sample matrix effects minimized via MIP for SERS detection of MG.

Development of a selective molecularly imprinted polymer for troponin T detection: a theoretical-experimental approach

The present work reports the synthesis and optimization of a molecularly imprinted polymer (MIP) for the selective recognition of troponin T. Troponin T is a cardiac protein found to be responsible for contraction and relaxation in the striated muscles; this protein acts as biomarker for the early diagnosis of acute myocardial infarction (AMI). This paper aims to present two aspects of a study conducted on the synthesis and application of MIP for troponin T detection. The first aspect focuses on the theoretical analysis conducted based on the application of Density Functional Theory (DFT) for the prior selection of the reaction solvent and functional monomers capable of interacting effectively with troponin T aiming at enhancing the efficiency of the synthesis. The second aspect of the study deals with the synthesis, optimization and characterization of the MIP for the analyte determination. Molecular dynamics simulations were made in order to have a better understanding of the analytical system. The findings from the computational simulations help elucidate why it is difficult to create biomimetic polymers for bio-macromolecules and point to solutions that can enhance the effectiveness of the proposed MIP. The results obtained from ELISA adsorption tests showed a greater adsorption of troponin T in the MIP than in the non-imprinted polymer (NIP); the proposed MIP presented limits of detection and quantification of 17.18 ng mL−1 and 52.07 ng mL−1, respectively, and a linear response range of 25 ng mL−1 to 100 ng mL−1.

Novel Chemoresistive Sensor for Sensitive Detection of Pb2+ Ions Using an Interdigital Gold Electrode Fabricated with a Reduced Graphene Oxide-Based Ion-Imprinted Polymer.

This study presents novel chemoresistive reduced graphene oxide–ion-imprinted polymer (IIP–rGO)-based sensors for detection of lead (Pb2+) ions. The ion-imprinted polymer was synthesized by bulk polymerization and modified with a variable amount of rGO incorporated to form an IIP–rGO composite. The amount of rGO in the polymer matrix affected the sensor’s relative response, and 1:3 mass ratio produced excellent results, with a consistent trend as the concentration of Pb2+ ions increased in the solution. The decrease in relative resistance (ΔR/Ro) followed an exponential decay relationship between the ΔR/Ro response and the concentration of Pb2+ ions in aqueous solutions. After solving the exponential decay function, it is observed that the sensor has the upper limit of ΔR/Ro >1.7287 μg L–1, and the limit of detection of the sensor is 1.77 μg L–1. A nonimprinted polymer (NIP)-based sensor responded with a low relative resistance of the same magnitude although the concentration was varied. The response ratio of the IIP-based sensor to the NIP-based sensor (ΔR/Ro)IIP/(ΔR/Ro)NIP as a function of the concentration of Pb2+ ions in the solution shows that the response ratios recorded a maximum of around 22 at 50 μg L–1 and then decreased as the concentration increased, following an exponential decay function with the minimum ratio of 2.09 at 200 μg L–1 but never read 1. The sensor showed excellent selectivity against the bivalent cations Mn2+, Fe2+, Sn2+, and Ti2+. The sensor was capable of exhibiting 90% ΔR/Ro response repeatability in a consecutive test.

Synthesis, Evaluation, and Characterization of an Ergotamine Imprinted Styrene-Based Polymer for Potential Use as an Ergot Alkaloid Selective Adsorbent.

Alkaloid toxicities negatively impact livestock health and production. To assess alkaloid occurrences, adsorbent technologies may offer effective means to their extraction and isolation from a complex feed matrix. In this study, molecularly imprinted polymers (MIPs) were synthesized and evaluated for their specificity of binding to various ergot alkaloids. Co-polymers of styrene and hydroxyethyl methacrylate were synthesized in the absence or presence of an ergotamine (ETA) template, yielding non-imprinted polymer (NIP) and molecularly imprinted polymer (MIP), respectively. The influence of parameters such as pH, temperature, and initial concentration on the adsorption of ergot alkaloids was evaluated along with their application as solid phase extraction materials. Chemical and morphological properties were characterized. Adsorption was generally greater for MIP compared to NIP. Cross-reactivity with related alkaloids existed due to similarities in structure and functional groups and was dependent on the type and concentration of alkaloid and polymer type (alkaloid type × concentration × product; P < 0.05). The pH of the medium had no influence on the binding properties of polymers toward ETA within a pH range of 2–10. Binding was independent of temperature between 36 and 42 °C. When kinetics of adsorption were evaluated, the Langmuir isotherm had a better fit (R2 > 0.95) to adsorption equilibrium data than the Freundlich equation. The maximum amounts adsorbed (Qo) from the Langmuir model were 8.68 and 7.55 μM/g for MIP and NIP, respectively. Fourier transform infrared, scanning and tandem electron microscopy, and Brunauer–Emmett–Teller analysis confirmed a highly porous MIP structure with a greater surface area compared to NIP. Binding characteristics evaluated with computational strategy using molecular docking experiments and in vitro in a complex media (rumen fluid) indicated a stronger ETA adsorption by the tested composition selected among other polymeric materials and affinity of MIP compared with NIP. This study suggested the possible utility of MIP as a solid phase extraction sorbent for applications in analytical chemistry or sensing devices tailored to track ergot alkaloid incidence and the fate of those alkaloids in complex ruminal digestive samples.

Investigation of polyacrylamide hydrogel-based molecularly imprinted polymers using protein gel electrophoresis.

In conjunction with polyacrylamide gel electrophoresis (PAGE), molecular imprinting methods have been applied to produce a multilayer mini-slab in order to evaluate how selectively and specifically a hydrogel-based molecularly imprinted polymer (MIP) binds bovine haemoglobin (BHb, ~64.5 kDa). A three-layer mini-slab comprising an upper and lower layer and a MIP, or a non-imprinted control polymer dispersion middle layer has been investigated. The discriminating MIP layer, also based on polyacrylamide, was able to specifically bind BHb molecules in preference to a protein similar in molecular weight such as bovine serum albumin (BSA, ~66 kDa). Protein staining allowed us to visualise the protein retention strength of the MIP layer under the influence of an electric field. This method could be applied to other proteins with implications in effective protein capture, disease diagnostics, and protein analysis.

The fabrication of molecularly imprinted polymer microspheres via Pickering emulsion polymerization stabilized with novel ferric hydroxide colloid

In this paper, the ferric hydroxide colloid was prepared firstly, which was found suitable for the stabilizer of Pickering emulsion because of proper hydrophilicity. Then, molecularly imprinted polymers (MIPs) microspheres were synthesized by means of facile Pickering emulsion polymerization using ferric hydroxide colloid as emulsifier. In the synthesis process, hydrophilic methacrylic acid was used for the functional monomer, and ethylene glycol dimethacrylate served as the crosslinking agent. Bisphenol A (BPA), a typical endocrine-disrupting chemical, was used for the template molecules. The whole synthesis was based on the hydrogen bonds interaction between the functional monomer and template molecule. The ferric hydroxide colloid could be removed from the surface of microspheres by gentle washing. The morphology of obtained MIPs microspheres were assessed through the optical microscope and field emission scanning electron microscope, respectively. The results suggested that the MIPs appeared the regular spherical form with relatively wide size distribution, whose diameter varied from 10 to 60 μm. The adsorptive property was studied detailedly through a series of rebinding experiments. The research showed that MIPs have fast binding kinetics, whose rebinding equilibrium in tested concentration could be achieved within 60 min, and the rebinding capacity in 0.3 mmol L−1 of BPA initial solution is 8.19 μmol g−1. Additionally, the binding capacities of MIPs were larger than that of non-imprinted polymers in the batch equilibrium binding experiments. The binding selectivity was investigated with 4, 4′-biphenol and hydroquinone, which played the role of the structurally similar compounds of template molecules. The result showed that the MIPs were highly selective for BPA, and the imprinting factor was calculated to be 1.63. Reusability experiment indicates that our prepared MIPs have good mechanical stability and could be reused at least 5 times. The MIPs microspheres would be valuable in the field of environmental protection.

Sensitive and Selective Detection of N,N-Dimethyltryptamine with Molecularly Imprinted Polymer Coupled with Electrogenerated Chemiluminescence

One of the challenges in analytical chemistry is to develop a method that is not only sensitive but also selective for detection and quantification of a target analyte. Herein, we report a strategy that combines a molecularly imprinted polymer (MIP) as the selective element with electrogenerated chemiluminescence (ECL) as the sensitive analytical signal generator for detection of a hallucinogenic drug N,N-dimethyltryptamine (DMT). MIPs hold specific binding capability toward probed targets, and their molecular recognition behavior is similar to that of specific antibodies to antigens or probe single-strand DNAs to complemental target DNA sequencies. Additionally, MIPs are chemically stable, easily synthesized, and cost-effective. On the other hand, ECL has been regarded as one of the most sensitive analytical techniques for ultra-trace analyte determination. This is because ECL is a kind of spectroscopy initiated by electrochemistry without using any light source. For the present work, DMT specific MIPs were prepared by anodic electrodeposition of aminobenzoic acid as monomer mixed with DMT as template molecule on a glassy carbon electrode that had coated with a Ru(bpy)3 2+ trapped nafion film. ECL signals at the electrodes with DMT immobilized MIPs were acquired in a phosphate buffered solution upon the anodic potential scanning. A non-imprinted polymer (NIP) was also prepared in absence of template under similar conditions. The MIP-ECL sensor showed a wide dynamic range of 0.05 to 100 µM to DMT with an estimated detection limit of 0.05 µM. The reproducibility, stability, and selectivity of the sensor were also examined. Figure 1

Vortex-Assisted Dispersive Molecularly Imprinted Polymer-Based Solid Phase Extraction of Acetaminophen from Water Samples Prior to HPLC-DAD Determination

In the present study, acetaminophen (ACT) molecularly imprinted polymer (ACT-MIP) were successfully synthesized via surface imprinting polymerization. The structural and morphological properties of ACT-MIP were characterized using various analytical techniques. ACT-MIP were used as an adsorbent in a vortex-assisted dispersive molecularly imprinted solid-phase micro-extraction (VA-d-μ-MISPE), coupled with a high-performance liquid chromatography–diode array detector (HPLC-DAD) method for the determination of ACT in water samples. Influential parameters such as the mass of adsorbent, vortex speed, extraction time, desorption volume, and desorption time were optimized using a multivariate approach. Under optimum conditions, the maximum binding capacities of ACT-MIP and NIP (non-imprinted polymers) were 191 mg/g and 71.5 mg/g, respectively. The linearity was attained across concentrations ranging from 0.630 to 500 µg/L, with a coefficient of determination of 0.9959. For ACT-MIP, the limit of detection (LOD) and limit of quantification (LOQ), enhancement factor, and precision of the method were 0.19 ng/L, 0.63 ng/L, 79, and &lt;5%, respectively. The method was applied in the analysis of spiked water samples, and satisfactory percentage recoveries in the range of 95.3–99.8% were obtained.

A porous molecularly imprinted nanofilm for selective and sensitive sensing of an anticancer drug ruxolitinib

A novel methodology has been applied to generate a porous molecularly imprinted material for highly selective and sensitive recognition of Janus kinase inhibitor ruxolitinib (RUX). The porous material-based nucleobase-derivative functional monomer was developed by a photopolymerization method. The thymine methacrylate (ThyM) as a functional monomer was synthesized and copolymerized with 2-hydroxyethyl methacrylate (HEMA) in the presence of ethylene glycol dimethacrylate (EGDMA) onto the glassy carbon electrode [glassy carbon electrode/molecularly imprinted polymer@poly(2-hydroxyethyl methacrylate-co-thymine methacrylate), (GCE/MIP@PHEMA-ThyM)] for the first time. The presence of ThyM results in the functional groups in imprinting binding sites, while the presence of poly(vinyl alcohol) (PVA) allows to generate porous materials for sensitive sensing. The characterization of GCE/MIP@PHEMA-ThyM was investigated by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and impedance spectroscopy technique. Then, the porous MIP modified glassy carbon electrode was optimized with effecting parameters including removal agent, removal time, and incubation time to get a better response for RUX. Under well-controlled optimum conditions, the GCE/MIP@PHEMA-ThyM linearly responded to the RUX concentration up to 0.01 pM at the limit of detection (LOD) of 0.00191 pM. The non-imprinted polymer (NIP) was also prepared to serve as a control in the same way but without the template. The proposed method improves the accessibility of binding sites by generating the porous material resulting in highly selective and sensitive recognition of drugs in the pharmaceutical dosage form and synthetic human serum samples.

Preparation of molecularly imprinted polymers-functionalized silica nanoparticles for the separation and recognition of aristolochic acids

马兜铃酸是马兜铃科植物中含有硝基菲羧酸基团的一类物质,被广泛应用于各种疾病的治疗,研究表明含有马兜铃酸的植物或植物衍生产品对人体有害,需要监测药物中马兜铃酸的存在。分子印迹聚合物对目标物的高亲和力使其特别适合作为吸附剂从混合物中去除和识别目标物。以SiO2胶体纳米颗粒为基底,利用表面分子印迹的方法合成了核-壳结构SiO2表面印迹纳米颗粒(SiO2@MIP NPs)。采用紫外可见光谱研究了模板分子马兜铃酸Ⅰ和功能单体丙烯酸、甲基丙烯酸、2-乙烯基吡啶、丙烯酰胺及甲基丙烯酰胺的作用,发现2-乙烯基吡啶与马兜铃酸Ⅰ的作用最强,被选为制备印迹聚合物的单体。采用傅立叶变换红外光谱仪(FT-IR)、透射电子显微镜(TEM)、热重分析仪、氮气吸附比表面分析仪对分子印迹聚合物进行了表征。TEM显示印迹纳米颗粒的粒径在270 nm左右,分子印迹层的厚度为35 nm,有利于模板分子的传输。TEM、FT-IR和热重分析仪的结果均证明实验成功合成了分子印迹聚合物。实验进一步研究了印迹聚合物SiO2@MIP NPs和非印迹聚合物SiO2@NIP NPs的吸附性能,并结合SiO2@MIP NPs和SiO2@NIP NPs的比表面积和孔径测定数据,发现SiO2@MIP NPs表面的印迹位点是导致二者吸附差异的主要原因。SiO2@MIP NPs和SiO2@NIP NPs的动力学吸附表明SiO2@MIP NPs具有快的吸附平衡时间(120 s),而且SiO2@MIP NPs的吸附行为符合Langmuir单分子层吸附。SiO2@MIP NPs的选择性通过印迹因子(IF)和选择性系数(SC)来评价。实验结果表明,SiO2@MIP NPs具有高的印迹因子(4.9),对模板结构类似物有较好的选择性,选择系数为2.3~6.6。最后将制备的SiO2@MIP NPs作为吸附剂用于加标中药样品川木通的预处理,用HPLC进行分析测定,方法的回收率为73%~83%,实验结果显示SiO2@MIP NPs可作为高选择性材料用于中药中马兜铃酸的选择性分离分析。