Molecularly imprinted polymer solid-phase extraction for detection of zearalenone in cereal sample extracts

Mycotoxins-Imprinted Polymers: A State-of-the-Art Review

Mycotoxins are toxic metabolites of molds which can contaminate food and beverages. Because of their acute and chronic toxicity, they can have harmful effects when ingested or inhaled, posing severe risks to human health. Contemporary analytical methods have the sensitivity required for contamination detection and quantification, but the direct application of these methods on real samples is not straightforward because of matrix complexity, and clean-up and preconcentration steps are needed, more and more requiring the application of highly selective solid-phase extraction materials. Molecularly imprinted polymers (MIPs) are artificial receptors mimicking the natural antibodies that are increasingly being used as a solid phase in extraction methods where selectivity towards target analytes is mandatory. In this review, the state-of-the-art about molecularly imprinted polymers as solid-phase extraction materials in mycotoxin contamination analysis will be discussed, with particular attention paid to the use of mimic molecules in the synthesis of mycotoxin-imprinted materials, to the application of these materials to food real samples, and to the development of advanced extraction methods involving molecular imprinting technology.

Recent Advances in Mycotoxin Determination in Fish Feed Ingredients

Low-cost plant-based sources used in aquaculture diets are prone to the occurrence of animal feed contaminants, which may in certain conditions affect the quality and safety of aquafeeds. Mycotoxins, a toxic group of small organic molecules produced by fungi, comprise a frequently occurring plant-based feed contaminant in aquafeeds. Mycotoxin contamination can potentially cause significant mortality, reduced productivity, and higher disease susceptibility; thus, its timely detection is crucial to the aquaculture industry. The present review summarizes the methodological advances, developed mainly during the past decade, related to mycotoxin detection in aquafeed ingredients, namely analytical, chromatographic, and immunological methodologies, as well as the use of biosensors and spectroscopic methods which are becoming more prevalent. Rapid and accurate mycotoxin detection is and will continue to be crucial to the food industry, animal production, and the environment, resulting in further improvements and developments in mycotoxin detection techniques.

An advantageous application of molecularly imprinted polymers in food processing and quality control

In the global market era, food product control is very challenging. It is impossible to track and control all production and delivery chains not only for regular customers but also for the State Sanitary Inspections. Certified laboratories currently use accurate food safety and quality inspection methods. However, these methods are very laborious and costly. The present review highlights the need to develop fast, robust, and cost-effective analytical assays to determine food contamination. Application of the molecularly imprinted polymers (MIPs) as selective recognition units for chemosensors' fabrication was herein explored. MIPs enable fast and inexpensive electrochemical and optical transduction, significantly improving detectability, sensitivity, and selectivity. MIPs compromise durability of synthetic materials with a high affinity to target analytes and selectivity of molecular recognition. Imprinted molecular cavities, present in MIPs structure, are complementary to the target analyte molecules in terms of size, shape, and location of recognizing sites. They perfectly mimic natural molecular recognition. The present review article critically covers MIPs' applications in selective assays for a wide range of food products. Moreover, numerous potential applications of MIPs in the food industry, including sample pretreatment before analysis, removal of contaminants, or extraction of high-value ingredients, are discussed.

Solid-phase extraction techniques based on nanomaterials for mycotoxin analysis: An overview for food and agricultural products

Mycotoxin contamination is a globally concerned problem for food and agricultural products since it may directly or indirectly induce severe threats to human health. Sensitive and selective screening is an efficient strategy to prevent or reduce human and animal exposure to mycotoxins. However, enormous challenges exist in the determination of mycotoxins, arising from complex sample matrices, trace-level analytes, and the co-occurrence of diverse mycotoxins. Appropriate sample preparation is essential to isolate, purify, and enrich mycotoxins from complicated matrices, thus decreasing sample matrix effects and lowering detection limits. With the cross-disciplinary development, new solid-phase extraction strategies have been exploited and integrated with nanotechnology to meet the challenges of mycotoxin analysis. This review summarizes the advance and progress of solid-phase extraction techniques as the methodological solutions for mycotoxin analysis. Emphases are paid on nanomaterials fabricated as trapping media of SPE techniques, including carbonaceous nanoparticles, metal/metal oxide-based nanoparticles, and nanoporous materials. Advantages and limitations are discussed, along with the potential prospects. This article is protected by copyright. All rights reserved.

Recent Progress in Rapid Determination of Mycotoxins Based on Emerging Biorecognition Molecules: A Review

Mycotoxins are secondary metabolites produced by fungal species, which pose significant risk to humans and livestock. The mycotoxins which are produced from Aspergillus, Penicillium, and Fusarium are considered most important and therefore regulated in food- and feedstuffs. Analyses are predominantly performed by official laboratory methods in centralized labs by expert technicians. There is an urgent demand for new low-cost, easy-to-use, and portable analytical devices for rapid on-site determination. Most significant advances were realized in the field bioanalytical techniques based on molecular recognition. This review aims to discuss recent progress in the generation of native biomolecules and new bioinspired materials towards mycotoxins for the development of reliable bioreceptor-based analytical methods. After brief presentation of basic knowledge regarding characteristics of most important mycotoxins, the generation, benefits, and limitations of present and emerging biorecognition molecules, such as polyclonal (pAb), monoclonal (mAb), recombinant antibodies (rAb), aptamers, short peptides, and molecularly imprinted polymers (MIPs), are discussed. Hereinafter, the use of binders in different areas of application, including sample preparation, microplate- and tube-based assays, lateral flow devices, and biosensors, is highlighted. Special focus, on a global scale, is placed on commercial availability of single receptor molecules, test-kits, and biosensor platforms using multiplexed bead-based suspension assays and planar biochip arrays. Future outlook is given with special emphasis on new challenges, such as increasing use of rAb based on synthetic and naïve antibody libraries to renounce animal immunization, multiple-analyte test-kits and high-throughput multiplexing, and determination of masked mycotoxins, including stereoisomeric degradation products.

The Existing Methods and Novel Approaches in Mycotoxins' Detection

Mycotoxins represent a wide range of secondary, naturally occurring and practically unavoidable fungal metabolites. They contaminate various agricultural commodities like cereals, maize, peanuts, fruits, and feed at any stage in pre- or post-harvest conditions. Consumption of mycotoxin-contaminated food and feed can cause acute or chronic toxicity in human and animals. The risk that is posed to public health have prompted the need to develop methods of analysis and detection of mycotoxins in food products. Mycotoxins wide range of structural diversity, high chemical stability, and low concentrations in tested samples require robust, effective, and comprehensible detection methods. This review summarizes current methods, such as chromatographic and immunochemical techniques, as well as novel, alternative approaches like biosensors, electronic noses, or molecularly imprinted polymers that have been successfully applied in detection and identification of various mycotoxins in food commodities. In order to highlight the significance of sampling and sample treatment in the analytical process, these steps have been comprehensively described.

Typical Fluorescent Sensors Exploiting Molecularly Imprinted Hydrogels for Environmentally and Medicinally Important Analytes Detection

In this work, two typical fluorescent sensors were generated by exploiting molecularly imprinted polymeric hydrogels (MIPGs) for zearalenone (ZON) and glucuronic acid (GA) detection, via the analyte's self-fluorescence property and receptor's fluorescence effect, respectively. Though significant advances have been achieved on MIPG-fluorescent sensors endowed with superior stability over natural receptor-sensors, there is an increasing demand for developing sensing devices with cost-effective, easy-to-use, portable advantages in terms of commercialization. Zooming in on the commercial potential of MIPG-fluorescent sensors, the MIPG_ZON is synthesized using zearalanone (an analogue of ZON) as template, which exhibits good detection performance even in corn samples with a limit of detection of 1.6 μM. In parallel, fluorescein-incorporated MIPG_GA is obtained and directly used for cancer cell imaging, with significant specificity and selectivity. Last but not least, our consolidated application results unfold new opportunities for MIPG-fluorescent sensors for environmentally and medicinally important analytes detection.

Nanoplatform-Integrated Miniaturized Solid-Phase Extraction Techniques: A Critical Review

Preparation of the biological samples is one of the most critical steps in sample analysis. In past decades, the liquid-liquid extraction technique has been used to extract the desired analytes from complex biological matrices. However, solid-phase extraction (SPE) gained popularity due to versatility, simplicity, selectivity, reproducibility, high sample recovery %, solvent economy, and time-saving nature. The superior extraction efficiency of SPE can be attributed to the development of advanced techniques, including the nanosorbents technology. The nanosorbent technology significantly simplified the sample preparation, improved the selectivity, diversified the application, and accelerated the sample analysis. This review critically expands on the to-date advancements reported in SPE with particular regards to the nanosorbent technology.

Development of ultrasound-assisted mixture extraction and online extraction solution concentration coupled with countercurrent chromatography for the preparation of pure phytochemicals from Phellinus vaninii

Herein, ultrasound-assisted mixture extraction (UAME) and online extraction solution concentration (OESC) were conducted to extract products from crops and plants. These techniques were coupled with parallel countercurrent chromatography (PCCC) and applied for continuous extraction and online isolation of chemical constituents from Phellinus vaninii. The UAME instrument comprises extraction and solution separation chambers. It provides higher extraction efficiency and fewer impurities and is suitable for processing various sample matrices. The OESC device comprises a spray nozzle, concentrating cylinder, and hot-blast air nozzle. The mechanical parameters for UAME and OESC were optimized, and the operation of online UAME and OESC coupled with PCCC was described. Raw plant materials were extracted using a two-phase extractant comprising petroleum-ethyl acetate-ethanol-water (0.5:2.0:0.5:2.0, v/v/v/v). The aqueous and organic phases were then concentrated using the OESC technique. Two CCC runs were conducted for preparatory work. After extraction and online concentration, the concentrate was pumped into the CCC for separation. During PCCC separation, continuous automated extraction and concentration were still conducted. When the first cycle of the UAME/OESC/PCCC was completed, followed by the initiation of the second cycle, and the process was continued. Six target compounds with purities exceeding 97.22% were successfully separated using the CCC solvent systems comprising n-hexane-ethyl acetate-acetonitrile-water (5.5:2.5:5.0:0.4, v/v/v/v) and n-butanol-ethanol-water (4.5:1.3:6.5, v/v/v). Compared with conventional extraction methods, the proposed UAME/OESC/PCCC method has higher efficiency, facilitates high-purity separation of analytes, and offers opportunity for automation and systematic preparation of natural products.

Development of ultrasound-assisted centrifugal extraction combined with two countercurrent chromatography systems for the simultaneous extraction and isolation of phytochemicals

We proposed a method for the extraction of medicinal herbs, called ultrasound-assisted centrifugal extraction, and an online solvent concentration method. These techniques were coupled with two countercurrent chromatography systems and applied to the continuous extraction and online isolation of chemical constituents from Inonotus obliquus. Raw plants were extracted using a two-phase petroleum-ethanol-water (2.0:1.0:2.0, v/v/v) process, and then the aqueous and organic phases were concentrated using the proposed online solvent concentrator. The countercurrent chromatography preparation prior to separation includes pumping of the two-phase solution, rotating column, and equilibrium column. Following online concentration, the extracted solution was pumped into a second countercurrent chromatography process for separation. During separation, the extraction solution and concentrated extract were prepared automatically. Upon completion of the first cycle of ultrasound-assisted centrifugal extraction/two countercurrent chromatography, the second cycle experiment starts. This process can be indefinitely repeated. In this study, six target compounds with purities above 97.71% were successfully extracted and isolated online using a two-phase solvent system consisting of n-hexane-ethyl acetate-acetonitrile (4.5:1.5:5.5, v/v/v) and n-hexane-ethyl acetate-methanol-water (0.4:3.0:1.5:2.5, v/v/v/v). Compared to conventional extraction methods, the instrumental setup of the proposed method provides enhanced automation, efficiency, purity, and systematic extraction and isolation of natural products.

Online specific recognition of mycotoxins using aptamer-grafted ionic affinity monolith with mixed-mode mechanism

Herein, a facile and practical aptamer-grafted ionic affinity monolith with mixed-mode mechanism was explored as a versatile platform for online specific recognition of polar and non-polar mycotoxins. The mixed-mode mechanism including molecular affinity adsorption (between aptamers and targets), hydrophilic interaction and ionic interaction (between stationary phase and targets) were adopted and provided a better flexibility in adjusting separation selectivity to reduce nonspecific adsorption with respect to the single mode. Preparation and characterization of aptamer-based affinity monoliths were investigated, The characterization of pore size distribution, Brunauer-Emmett-Teller (BET) surface area and the specificity and cross-reaction were also evaluated. As a result, the hydrophilic nature and negative charge on affinity monolith were obtained. Multiple interactions including aptamer affinity binding, hydrophilic interaction (HI) and ion exchange (IE) could be adopted for online selective extraction. Specific recognitions of polar ochratoxin A (OTA), non-polar zearalenone (ZEN) and aflatoxin B1 (AFB1) was fulfilled with LODs as 0.03, 0.05 and 0.05 μg/L, respectively. Applied to real cereals, good recoveries of the fortified OTA, AFB1 and ZEN were achieved as 92.6 ± 1.3% ~ 95.6 ± 1.3% (n=3), 93.9 ± 2.3% ~ 98.2 ± 3.4% (n=3) and 92.7 ± 2.0% ~ 96.9 ± 3.5% (n=3) in corn, wheat and rice, respectively. The results displayed that Apt-MCs with hydrophilic and ionic interaction mixed-mode mechanism were efficient enough and competent for the online recognition of mycotoxins in cereals.

Molecularly Imprinted Polymer as Selective Sorbent for the Extraction of Zearalenone in Edible Vegetable Oils

A method based on the selective extraction of zearalenone (ZON) from edible vegetable oils using molecularly imprinted polymer (MIP) has been developed and validated. Ultra-high-pressure liquid chromatography coupled with a fluorescence detection system was employed for the detection of zearalenone. The method was applied to the analysis of zearalenone in maize oil samples spiked at four concentration levels within the maximum permitted amount specified by the European Commission Regulation (EC) No. 1126/2007. As a result, the proposed methodology provided high recoveries (>72%) with good linearity (R2 > 0.999) in the range of 10-2000 μg/kg and a repeatability relative standard deviation below 1.8%. These findings meet the analytical performance criteria specified by the European Commission Regulation No. 401/2006 and reveal that the proposed methodology can be successfully applied for monitoring zearalenone at trace levels in different edible vegetable oils. A comparison of MIP behavior with the ones of QuEChERS and liquid-liquid extraction was also performed, showing higher extraction rates and precision of MIP. Finally, the evolution of ZON contamination during the maize oil refining process was also investigated, demonstrating how the process is unable to completely remove (60%) ZON from oil samples.

Application of surface-imprinted polymers supported by hydroxyapatite in the extraction of zearalenone in various cereals

Surface-imprinted polymers supported by hydroxyapatite (HAP@MIPs) were prepared using coumarin-3-carboxylic acid and naringenin as dummy template molecules of zearalenone (ZEA). HAP@MIPs were characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, particle size distribution analysis, energy-dispersive X-ray spectroscopy, and X-ray diffraction. The adsorption performance was studied. The results showed that it could reach the adsorption equilibrium within 6 min. The adsorption amount could reach 6.77 μg mg^-1, while the concentration was 20 μg mL^-1. The self-made solid-phase extraction (SPE) columns were prepared with HAP@MIPs as sorbents for the separation and purification of ZEA in cereal samples. The method was established by high-performance liquid chromatography (HPLC). The recoveries were in the range of 70.09-101.88%; the relative standard deviation was 2.06-8.47%. Finally, millet, coix lachryma, and corn were placed under extreme conditions to produce ZEA. The method was used to extract and analyze ZEA in the above samples. The results showed that self-made SPE columns with HPLC could be used for the separation and enrichment of ZEA in real samples. Graphical abstract.

Towards high-efficient online specific discrimination of zearalenone by using gold nanoparticles@aptamer-based affinity monolithic column

Sensitive and specific analysis of zearalenone (ZEN) mycotoxin in cereals for ensuring food safety is critical and remains challenging. Herein, a new gold nanoparticles @aptamer-functionalized hybrid affinity monolithic column was proposed and employed for online specific recognition of ZEN by HPLC. Characterization on the morphology, Brunauer-Emmett-Teller (BET) surface area mechanical stability and specific performance of the obtained affinity monolith were investigated. A super-high aptamer coverage density could reach 3636 pmol/μL, which is preferable to gain an effective analysis of ZEN with high specificity and a low interference of co-existed substances including typical α-Zearalenol (α-ZOL) and Aflatoxin B₁ (AFB₁). The sensitive recognition of trace ZEN was obtained with the limit of detection (LOD) as low as 0.05 ng/mL. Applied to real cereal samples, satisfactory recoveries were obtained in the range of 91.6 ± 1.4%-97.8 ± 2.6% (n = 3) in corn, 93.8 ± 3.1%-95.0 ± 3.6% (n = 3) in wheat, and 90.9 ± 4.7%-94.7 ± 3.8% (n = 3) in rice, respectively. The results on quantitative analysis were similar to that of LC-MS and better than that obtained by using immunoaffinity column (IAC) or molecularly imprinted polymer (MIP). This protocol provided an efficient access to high-efficient online specific recognition of ZEN in cereals by using such an aptamer-affinity capillary monolithic column.

Synthesis and application of magnetic-surfaced pseudo molecularly imprinted polymers for zearalenone pretreatment in cereal samples

Zearalenone (ZEA) is a fungal contaminant widely found in grains. In cereal samples, trace zearalenone was extracted and enriched using magnetic-surfaced pseudo molecularly imprinted polymers (SPMIPs) and detected. SPMIPs were prepared with Fe₃O₄ as the magnetic core, modified halloysites nanotubes as supporting materials, and selective imprinted polymers as shells. Vinyl was modified on the surface of halloysites nanotube. SPMIPs were synthesized with pseudo templates. SPMIPs as the adsorbent of dispersed-solid phase extraction (μ-SPE) were used to purify and enrich ZEA from maize samples. After optimized, the pretreatment method was evaluated. The linearity of the method was ranged within 10-200 ng mL^-1. LOD and LOQ were 2.5 ng mL^-1 and 8 ng mL^-1 respectively. The ZEA spiking recoveries in maize samples ranged within 74.95-88.41% were with good RSDs lower than 4.25%. The developed method was successful applied in maize, oat, and wheat sample treatments and compared.

A Novel Magnetic Molecular Imprinted Polymer for Selective Extraction of Zearalenone from Cereal Flours before Liquid Chromatography-Tandem Mass Spectrometry Determination

Zearalenone (ZEN) is a nonsteroidal estrogenic mycotoxin produced by various Fusarium species and commonly occurring in corn and other cereals. Even though its acute toxicity is low, still the estrogenic activity of ZEN and metabolites is a matter of concern. In this work, a new magnetic molecularly imprinted polymer (mMIP) for the selective extraction of ZEN from cereal flours is presented. The mMIP was synthesized previously using quercetin as dummy template, and here we wanted to test its applicability to complex food samples. Analyte determination was carried out by high-performance liquid chromatography coupled to tandem mass spectrometry. The selectivity of the mMIP and the main validation method parameters were assessed. In particular, even in samples as complex as cereals, matrix effect was negligible. Although the mMIP showed cross-selectivity towards both ZEN-related and quercetin-related compounds, nonetheless ZEN recovery was > 95% for the two lower spiking levels, and the quantification limit was 0.14 ng g⁻¹, i.e., ca. 500 times lower than the maximum limit fixed for most cereals by European law. Therefore, the material, also in comparison with a commercial sorbent, appears suitable for the application in food analysis, also to isolate ZEN at trace levels.

An amperometric zearalenone aptasensor based on signal amplification by using a composite prepared from porous platinum nanotubes, gold nanoparticles and thionine-labelled graphene oxide

The authors constructed a voltammetric zearalenone (ZEN) aptasensor based on use of porous platinum nanotubes, gold nanoparticles (p-PtNTs/AuNPs) and thionine (Thi) labelled graphene oxide (GO). The p-PtNTs were synthesized in-situ based on tellurium nanowires as sacrificial templates. Subsequently, thiol-modified aptamers were self-assembled on the AuNPs that had been electrodeposited on the surface of the modified electrode. The presence of p-PtNTs on the electrode increases the loading with AuNPs and aptamers. It also warrants that the Thi-labelled GO can be assembled onto the aptamer via π interactions. In the presence of ZEN, it will be bound by the aptamer. The GO/Thi conjugate will be released from the aptamer, and this causes a decrease in Thi current. Under the optimal conditions and at a typical working potential of -0.22 V (vs. Ag/AgCl), the method has a linear range that covers the 0.5 pg·mL^-1 to 0.5 μg·mL^-1 ZEN concentraion range and a lower detection limit of 0.17 pg·mL^-1. Graphical abstract Voltammetric zearalenone aptasensor based on use of porous platinum nanotubes/gold nanoparticles and thionine labelled graphene oxide was fabricated for the detection of zearalenone.

Quantitative assessment of zearalenone in maize using multivariate algorithms coupled to Raman spectroscopy

Zearalenone is a contaminant in food and feed products which are hazardous to humans and animals. This study explored the feasibility of the Raman rapid screening technique for zearalenone in contaminated maize. For representative Raman spectra acquisition, the ground maize samples were collected by extended sample area to avoid the adverse effect of heterogeneous component. Regression models were built with partial least squares (PLS) and compared with those built with other variable selection algorithms such as synergy interval PLS (siPLS), ant colony optimization PLS (ACO-PLS) and siPLS-ACO. SiPLS-ACO algorithm was superior to others in terms of predictive power performance for zearalenone analysis. The best model based on siPLS-ACO achieved coefficients of correlation (R_p) of 0.9260 and RMSEP of 87.9132 μg/kg in the prediction set, respectively. Raman spectroscopy combined multivariate calibration showed promising results for the rapid screening large numbers of zearalenone maize contaminations in bulk quantities without sample-extraction steps.

Novel molecularly imprinted polymers on metal–organic frameworks as sensors for the highly selective detection of zearalenone in wheat

This work provides a rapid and simple method for the determination of trace substances in complex systems.

Advancements of molecularly imprinted polymers in the food safety field

Molecularly imprinted technology (MIT) has been widely employed to produce stable, robust and cheap molecularly imprinted polymer (MIP) materials that possess selective binding sites for recognition of target analytes in food, such as pesticides, veterinary drugs, mycotoxins, illegal drugs and so on. Because of high selectivity and specificity, MIPs have drawn great attention in the food safety field. In this review, the recent developments of MIPs in various applications for food safety, including sample preparation, chromatographic separation, sensing, immunoassay etc., have been summarized. We particularly discuss the advancements and limitations in these applications, as well as attempts carried out for their improvement.

Computer-aided design of magnetic molecularly imprinted polymer nanoparticles for solid-phase extraction and determination of levetiracetam in human plasma

Analytical methods should be accurate and specific to measure plasma drug concentration. Nevertheless, current sample preparation techniques suffer from limitations, including matrix interference and intensive sample preparation. In this study, a novel technique was proposed for the synthesis of a molecularly imprinted polymer (MIP) on magnetic Fe₃O₄ nanoparticles (NPs) with uniform core–shell structure. The Fe₃O₄@MIPs NPs were then applied to separate and enrich an antiepileptic drug, levetiracetam, from human plasma. A computational approach was developed to screen the functional monomers and polymerization solvents to provide a suitable design for the synthesized MIP. Different analysis techniques and re-binding experiments were performed to characterize the Fe₃O₄@MIP NPs, as well as to identify optimal conditions for the extraction process. Adsorption isotherms were best fitted to the Langmuir model and adsorption kinetics were modeled with pseudo-second-order kinetics. The Fe₃O₄@MIP NPs showed reasonable adsorption capacity and improved imprinting efficiency. A validated colorimetric assay was introduced as a comparable method to a validated HPLC assay for the quantitation of levetiracetam in plasma in the range of 10–80 μg mL⁻¹ after extraction. The results from the HPLC and colorimetric assays showed good precision (between 1.08% and 9.87%) and recoveries (between 94% and 106%) using the Fe₃O₄@MIP NPs. The limit of detection and limit of quantification were estimated to be 2.58 μg mL⁻¹ and 7.81 μg mL⁻¹, respectively for HPLC assay and 2.32 μg mL⁻¹ and 7.02 μg mL⁻¹, respectively for colorimetric assay. It is believed that synthesized Fe₃O₄@MIP NPs as a sample clean-up technique combined with the proposed assays can be used for determination of levetiracetam in plasma.

A novel molecularly imprinted polymer on Fe₃O₄ nanoparticles was applied to extract antiepileptic drug; levetiracetam from plasma for TDM purposes.

Thermo-responsive molecularly imprinted polymer containing magnetic nanoparticles: Synthesis, characterization and adsorption properties for curcumin

A novel intelligent thermoresponsive-magnetic molecularly imprinted polymer (TMMIP) nanocomposite based on N-isopropylacrylamide (NIPAM) & Fe₃O₄ was designed for the controlled & sustained release of Curcumin (CUR) with the ability to response external stimulus. The TMMIP nanocomposite was prepared using acryl functionalized β-cyclodextrin (β-CD) and NIPAM as functional monomers and CUR as target molecule. The recognition cavities which caused by host-guest interactions had direct influence to enhanced drug loading and sustained release of CUR. According to in-vitro release experiment in two different temperatures (below & above LCST of NIPAM) the prolonged & controlled release of CUR were observed. The release rate could be controlled by changing the temperature because of the phase transition behavior of NIPAM monomer. Also, the proposed biosensor displayed effective role in separation science, reasonable adsorption capacity (77mgg^-1), fast recognition (10min equilibration), selective extraction toward CUR in the presence of structural analogues and easily separation using external magnetic field. Moreover, the synthesized TMMIP was confirmed by various characterization.

Recent configurations and progressive uses of magnetic molecularly imprinted polymers for drug analysis

Since the introduction of the molecularly imprinting technology (MIT) in the 1970s, it becomes an emerging technology with the potential for wide-ranging applications in drug determination. With the rise of green chemistry, many researchers began to focus on the application and development of green materials which led to the breakthrough of molecularly imprinted polymers (MIPs) in the green chemistry. Because of the low concentration levels in the human matrices, almost adequate analytical methods should be used for quantification of drugs at the trace levels. In recent years there have been reported benefits of combining MIPs with additional features, e.g. magnetic properties, through the build-up of this type of material on magnetite particles. Magnetic molecularly imprinted polymer (MMIP) is a new material which is composed of magnetic material and non-magnetic polymer material and shares the characteristics of high adsorption capacity to template molecule, special selective recognition ability, and the magnetic adsorption property. These materials have been widely used in the different fields such as chemical, biological and medical science. This review describes the novel configurations and progressive applications of magnetic molecularly imprinted polymers to the drug analysis. Also, the advantages and drawbacks of each methodology, as well as the future expected trends, are evaluated.

Rational design, preparation and adsorption study of a magnetic molecularly imprinted polymer using a dummy template and a bifunctional monomer

In this study, a molecular docking method and solvation model in computer simulation were applied to simultaneously screen a dummy template and a bifunctional monomer in the rational design of a magnetic molecularly imprinted polymer.

New biorecognition molecules in biosensors for the detection of toxins

Biological and synthetic recognition elements are at the heart of the majority of modern bioreceptor assays. Traditionally, enzymes and antibodies have been integrated in the biosensor designs as a popular choice for the detection of toxin molecules. But since 1970s, alternative biological and synthetic binders have been emerged as a promising alternative to conventional biorecognition elements in detection systems for laboratory and field-based applications. Recent research has witnessed immense interest in the use of recombinant enzymatic methodologies and nanozymes to circumvent the drawbacks associated with natural enzymes. In the area of antibody production, technologies based on the modification of in vivo synthesized materials and in vitro approaches with development of "display "systems have been introduced in the recent years. Subsequently, molecularly-imprinted polymers and Peptide nucleic acid (PNAs) were developed as an attractive receptor with applications in the area of sample preparation and detection systems. In this article, we discuss all alternatives to conventional biomolecules employed in the detection of various toxin molecules We review recent developments in modified enzymes, nanozymes, nanobodies, aptamers, peptides, protein scaffolds and DNazymes. With the advent of nanostructures and new interface materials, these recognition elements will be major players in future biosensor development.

Molecularly imprinted polymer nanoparticles for olanzapine recognition: application for solid phase extraction and sustained release

The aim of this study was to prepare efficient imprinted polymer nanoparticles from an olanzapine template for the controlled release of olanzapine as a therapeutic drug for CNS diseases.

Solid-phase extraction using molecularly imprinted polymer for determination of ochratoxin A in human urine

A rapid, selective and reliable sample preparation technique employing solid-phase extraction (SPE) based on molecularly imprinted polymer (MIP) for the determination of ochratoxin A (OTA) in human urine was described. After sample adjustment to pH 2.5 with 0.1 M HCl, the urine sample was loaded onto the MIP-SPE column, and after a wash step, OTA was eluted for measurement by ultra-high performance liquid chromatography coupled with fluorescence detection. Key parameters which affected the MIP-SPE extraction efficiency were optimized as was the detection method. Under the optimised conditions, the limits of detection and quantification for OTA in urine were 0.2 ng/ml and 0.6 ng/ml, respectively. The recoveries for OTA in urine, spiked at the 0.6, 6.0 and 60 ng/ml levels, ranged from 92.0 to 98.9%. Sixty urine samples were analysed, of which four were found to contain OTA at concentrations ranging from 0.022 to 0.083 ng/ml; the positive results were confirmed by liquid chromatography coupled with tandem mass spectrometry. OTA determination in urine is a good indicator for human exposure to the mycotoxin, and this is the first report on OTA contamination in Chinese people.

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.

Molecularly imprinted solid-phase extraction for selective extraction of bisphenol analogues in beverages and canned food

This study aimed to develop a selective analytical method for the simultaneous determination of seven bisphenol analogues in beverage and canned food samples by using a new molecularly imprinted polymer (MIP) as a sorbent for solid-phase extraction (SPE). Liquid chromatography coupled to triple-quadruple tandem mass spectrometry (LC-MS/MS) was used to identify and quantify the target analytes. The MIP-SPE method exhibited a higher level of selectivity and purification than the traditional SPE method. The developed procedures were further validated in terms of accuracy, precision, and sensitivity. The obtained recoveries varied from 50% to 103% at three fortification levels and yielded a relative standard deviation (RSD, %) of less than 15% for all of the analytes. The limits of quantification (LOQ) for the seven analytes varied from 0.002 to 0.15 ng/mL for beverage samples and from 0.03 to 1.5 ng/g for canned food samples. This method was used to analyze real samples that were collected from a supermarket in Beijing. Overall, the results revealed that bisphenol A and bisphenol F were the most frequently detected bisphenols in the beverage and canned food samples and that their concentrations were closely associated with the type of packaging material. This study provides an alternative method of traditional SPE extraction for screening bisphenol analogues in food matrices.