Preparation of molecular imprinted polymers using bi-functional monomer and bi-crosslinker for solid-phase extraction of rutin

Current trends of functional monomers and cross linkers used to produce molecularly imprinted polymers for food analysis

Molecularly imprinted polymers (MIPs) as artificial synthetic receptors are in high demand for food analysis due to their inherent molecular recognition abilities. It is common practice to employ functional monomers with basic or acidic groups that can interact with analyte molecules via hydrogen bonds, covalent bonds, and other interactions (π-π, dipole-ion, hydrophobic, and Van der Waals). Therefore, selecting the appropriate functional monomer and cross-linker is crucial for determining how precisely they interact with the template and developing the polymeric network's three-dimensional structure. This study summarizes the advancements made in MIP's functional monomers and cross-linkers for food analysis from 2018 to 2023. The subsequent computational design of MIP has been thoroughly explained. The discussion has concluded with a look at the difficulties and prospects for MIP in food analysis.

Synthesis of molecularly imprinted polymer as a nanosorbent for dispersive magnetic micro solid-phase extraction and determination of valsartan in biological samples by UV-Vis Spectrophotometry: Isotherm, kinetics, and thermodynamic studies

A magnetic molecularly imprinted polymer (MIP) was synthesized by precipitation polymerization utilizing Fe₃O₄@SiO₂-MPS as a magnetic core, itaconic acid as a functional monomer, azobisisobutyronitrile as an initiator, and ethylene glycol dimethacrylate as a cross linker. It was then applied as a nanosorbent for dispersive magnetic micro solid phase extraction (DM-µ-SPE) and determination of valsartan in biological fluids. The morphology and structure of magnetic MIP were characterized by Fourier-transform infrared spectroscopy, Field Emission Scanning electron microscopy, Vibrating sample magnetometer, Energy dispersive x-ray analysis, and Thermogravimetric analysis. The influence of operation conditions on sorption, such as pH (4-10), contact time (10-25 min), initial concentration (1-30 mg L^-1), and temperature (25-40 °C) was investigated. After the extraction step, the valsartan concentration was determined by UV-Vis spectrophotometer at 253 nm. The isotherm and kinetic of valsartan sorption were best fitted by the Langmuir model (R² = 0.987) and the Pseudo second-order kinetic model (R² = 0.971), respectively. The maximum monolayer sorption capacity for magnetic MIP was obtained to be 4.56 mg g^-1. The analytical approach demonstrated favorable figures of merit, with a linear dynamic range of 10-100 µg L^-1, a low detection limit of 0.56 µg L^-1, and an acceptable preconcentration factor of 5 acquired in optimum conditions. The recoveries of the suggested technique at three spiked levels of analysis were in the range of 101 %-102 %. Valsartan was extracted from various real samples (urine and human blood plasma samples) utilizing the proposed magnetic nanosorbent, and the results exhibited that magnetic MIP was favorable for extraction and measurement of trace amounts of valsartan in biological samples.

Fabrication of high-performance cell-imprinted polymers based on AuNPs/MXene composites via metal-free visible light-induced ATRP

Cell-imprinted polymers (CIPs) for yeasts were fabricated via metal-free visible-light-induced atom transfer radical polymerization (MVL ATRP) on the surface of a glassy carbon electrode (GCE) which had been modified with gold nanoparticles (AuNPs)/MXene (Ti₃C₂T_x) composites. Here, the AuNPs/Ti₃C₂T_x composites form a macroporous structure, which could improve the electron transfer rate of the materials and facilitate the leaving or rebinding of cells. Methacrylic acid (MAA) and N,N'-methylene bis-acrylamide (MBA) were selected as the functional monomer and cross-linker of CIPs, because they could form efficient hydrogen bonding with mannan from yeast cell walls. The obtained electrode (CIPs/AuNPs/Ti₃C₂T_x/GCE) was characterized by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Further experiments indicated that the CIPs/AuNPs/Ti₃C₂T_x/GCE electrode could be utilized as an electrochemical biosensor to determine yeast cells by differential pulse voltammetry (DPV). The linear response range was 1.0 × 10² to 1.0 × 10⁹ cells per mL and the detection limit was 20 cells per mL (S/N = 3). The CIPs/AuNPs/Ti₃C₂T_x/GCE electrode also showed good selectivity, repeatability, reproducibility, and regeneration. Finally, the proposed sensor was used to detect yeast cells in commercial samples of Saccharomyces boulardii sachets by a standard addition method. The obtained recovery was from 96.9 to 104.8% showing its potential applications in clinical and diagnostic research.

Magnetic Molecularly Imprinted Polymers for the Separation and Enrichment of Cannabidiol from Hemp Leaf Samples

Cannabidiol (CBD) has attracted immense attention due to its excellent clinical effects in the treatment of various diseases. However, rapid and accurate extraction of CBD from hemp plant concentrates remains a challenge. Thus, novel magnetic molecularly imprinted polymers (CBD-MMIPs) with specific recognizing capability for CBD were synthesized using ethylene glycol dimethacrylate as the cross-linker, CBD as the template, methacrylic acid as the functional monomer, azobisisobutyronitrile as the initiator, and Fe₃O₄ nanoparticles modified with SiO₂ as the magnetic carrier. The morphological, magnetic, and adsorption properties of obtained CBD-MMIPs were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, vibrating sample magnetometry, surface area and porosity analyses, and various adsorption experiments. The results showed that the CBD-MMIPs had selective specificity and high adsorption capacity for CBD. The adsorption of CBD by CBD-MMIPs could reach equilibrium in a short time (30 min), and the maximum adsorption capacity was as high as 26.51 mg/g. The specific recognition and selectivity properties of CBD-MMIPs to CBD were significantly higher than that of other structural analogues, and the regeneration tests established that the CBD-MMIPs had good recyclability. Furthermore, the CBD-MMIPs could be successfully used as an adsorbent to the extraction of CBD from hemp leaf sample concentrates with high recovery efficiencies (93.46-97.40%).

Synthesis of a magnetic micelle molecularly imprinted polymers to selective adsorption of rutin from Sophora japonica

Rutin is a naturally active compound with biological and medical value. The traditional extraction and separation method not only destroys the structure and activity of rutin, but results in a low extraction rate. In this work, the magnetic micellar molecularly imprinted polymer of rutin with a selective recognition function, i.e., RMMMIP was synthesized from 4 to Vinylphenylboron acid and 4-Vinylpyridine as functional monomer, derivatives of cholic acid as amphiphilic molecules. The internal hydrophobic and external hydrophilic characteristics of micelle was used to weaken the solvation of rutin and strengthen the non-covalent interaction between functional monomer and rutin. Fe₃O₄, as the core, endowed the composite materials with good magnetic responsiveness and was easy to separate solid from liquid. Then its structure and adsorption were studied, adsorbing capacity and recognition specific factor of RMMMIP are 11.9 mg·g^-1 and 3.55 respectively. RMMMIP was used for the separation of rutin from crude extracts of Sophora japonica Linn and showed a better selective adsorption capacity than quercetin, naringin and cyanidin-3-O-glucose. It indicated that RMMMIP as a specific adsorbent had the potential to be a practical way to purify rutin from rutin crude extracts in the future.

Deep-Eutectic-Solvent-Based Mesoporous Molecularly Imprinted Polymers for Purification of Gallic Acid from Camellia spp. Fruit Shells

To produce antioxidant substances from agricultural waste Camellia spp. fruit shells before their further utilization, gallic acid from five kinds of Camellia spp. fruit shells was separated on specific recognition by deep eutectic solvent molecularly imprinted polymers (DES@MIPs), which were prepared by bulk polymerization using gallic acid as the template and deep eutectic solvents (α-methylacrylic acid and choline chloride) as functional monomers. The optimized DES@MIPs were characterized by scanning electron microscopy, particle size analysis, nitrogen sorption porosimetry, elemental analysis, Fourier transform infrared spectroscopy, and thermal gravimetric analysis. The adsorptive behavior of gallic acid on DES@MIPs was also investigated. The results indicated that DES@MIPs were successfully prepared as mesoporous materials with average pore diameter of 9.65 nm and total pore volume of 0.315 cm³ g⁻¹, and the adsorption behavior was multilayer adsorption and pseudo-second-order kinetics with the saturation adsorptive capacity of gallic acid reaching 0.7110 mmol g⁻¹. Although the content of gallic acid in five fruit shells was quite different, the purification recovery of gallic acid was high, ranging from 87.85–96.75% with a purity over 80%. Thus, the purification of gallic acid from Camellia spp. fruit shells could be realized feasibly using DES@MIPs with favorable economic and environmental benefits.

Study of the Preparation and Properties of Chrysin Binary Functional Monomer Molecularly Imprinted Polymers

Chrysin is a natural bioactive molecule with various groups, and it has been a challenge to separate and enrich chrysin from natural products. Molecularly imprinted polymers have been widely used in the extraction of natural products, but the number and type of functional monomers limits the separation effect. The synergistic action of multiple functional monomers can improve the separation effect. In this paper, molecularly imprinted polymers (Bi-MIPs) were prepared using methacrylic acid and acrylamide as binary functional monomers for the separation and enrichment of chrysin. The Bi-MIPs were characterized using thermogravimetric analyzer (TGA), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM). The performances of Bi-MIPs were assessed, which included adsorption isotherms, selective recognition and adsorption kinetics. The experimental results show that Bi-MIPs are shaped as a uniform sphere with an abundant pocket structure on its surface. The adsorption of chrysin on the Bi-MIPs followed a pseudo-second-order and adapted Langmuir–Freundlich isotherm models. The adsorption performance of the Bi-MIPs was determined at different temperatures, and the Bi-MIPs showed excellent adsorption performance at 30 °C. The initial decomposition temperature of the Bi-MIPs was 220 °C. After five times of adsorption and desorption, the adsorption performance of the Bi-MIPs decreased by only 7%. In contrast with single functional monomer molecularly imprinted polymers (Si-MIPs), the Bi-MIPs showed excellent specificity, with an imprinting factor of 1.54. The Bi-MIPs are promising materials in the separation and enrichment of chrysin for their high adsorption capacity, low cost and being environmentally friendly.

Multifunctional Molecularly Imprinted Receptor-Based Polymeric Membrane Potentiometric Sensor for Sensitive Detection of Bisphenol A

Molecularly imprinted polymer (MIP)-based polymeric membrane potentiometric sensors have become an attractive tool for detection of organic species. However, the MIP receptors in potentiometric sensors developed so far are usually prepared by only using single functional monomers. This may lead to low affinities of the MIP receptors due to the lack of diversity of the functional groups, thus resulting in low detection sensitivity of the potentiometric sensors. Additionally, these classical MIP receptors are nonconductive polymers, which are undesirable for the fabrication of an electrochemical sensor. Herein, we describe a novel multifunctional MIP receptor-based potentiometric sensor. The multifunctional MIP receptor is prepared by using two functional monomers, methacrylic acid, and 3-vinylaniline with a dual functionality of both recognition and conduction properties. The poly(aniline) groups are introduced into the methacrylic acid-based MIP by postoxidation of the aniline monomer. Such poly(aniline) groups not only serve as the additional functional groups for selective recognition, but also work as a conducting polymer. The obtained multifunctional MIP receptor shows a high binding capacity and an excellent electron-transfer ability. By using bisphenol A as a model, the proposed multifunctional MIP sensor exhibits a largely improved sensitivity and low noise levels compared to the conventional MIP sensor. We believe that the proposed MIP-based sensing strategy provides a general and facile way to fabricate sensitive and selective MIP-based electrochemical sensors.

Molecular Dynamic Study of Mechanism Underlying Nature of Molecular Recognition and the Role of Crosslinker in the Synthesis of Salmeterol-Targeting Molecularly Imprinted Polymer for Analysis of Salmeterol Xinafoate in Biological Fluid

The rational preparation of molecularly imprinted polymers (MIPs) in order to have selective extraction of salmeterol xinafoate (SLX) from serum was studied. SLX is an acting β-adrenergic receptor agonist used in the treatment of asthma and has an athletic performance-enhancing effect. Molecular dynamics were used for the simulation of the SLX-imprinted pre-polymerization system, to determine the stability of the system. The computational simulation showed that SLX as a template, 4-hydroxyethyl methacrylate (HEMA) as a monomer, and trimethylolpropane trimethacrylate (TRIM) as a crosslinker in mol ratio of 1:6:20 had the strongest interaction in terms of the radial distribution functional. To validate the computational result, four polymers were synthesized using the precipitation polymerization method, and MIP with composition and ratio corresponding with the system with the strongest interaction as an MD simulation result showed the best performance, with a recovery of 96.59 ± 2.24% of SLX in spiked serum and 92.25 ± 1.12% when SLX was spiked with another analogue structure. Compared with the standard solid phase extraction sorbent C-18, which had a recovery of 79.11 ± 2.96%, the MIP showed better performance. The harmony between the simulation and experimental results illustrates that the molecular dynamic simulations had a significant role in the study and development of the MIPs for analysis of SLX in biological fluid.

Molecularly imprinted polymers for arbutin and rutin by modified precipitation polymerization and their application for selective extraction of rutin in nutritional supplements

Molecularly imprinted polymers (MIPs) for glycosides, arbutin (ARB) and rutin (RUT), were prepared using methacrylamide (MAM) and 4-vinylpyridine (4-VPY) as functional monomers and divinylbenzene as a crosslinker by modified precipitation polymerization. The template molecule, ARB or RUT, was first dissolved in methanol, followed by precipitation polymerization using a mixture of acetonitrile and toluene as a porogenic solvent. The molar ratios of the template molecule, MAM and 4-VPY were optimized to achieve a high molecular recognition ability for ARB and RUT. The retention and molecular recognition properties of these MIPs were evaluated in HILIC or normal-phase mode. With an increase in the acetonitrile content in the mobile phase, the retention factor of ARB or RUT was increased. Furthermore, the MIPs for ARB and RUT showed the highest imprinting factors of 3.65 and 66.5 for the template molecules, respectively. Hydrogen bonding interactions such as N⋯H-O, C=O⋯H-O and NH⋯O-H between 4-VPY or MAM and hydroxy groups of d-glucose or d-rutinose could function in the recognition of a glycone. Furthermore, hydrogen bonding interactions between functional monomers and the hydroxy group(s) of hydroquinone or quercetin could function in the recognition of an aglycone. These results suggest that the MIPs could recognize both a glycone and aglycone via hydrogen bonding interactions. Furthermore, MIPs for RUT were successfully applied to extract RUT in nutritional supplements.

Environmental impact of molecularly imprinted polymers used as analyte sorbents in mass spectrometry

The molecularly imprinted polymers (MIPs) with the following herbicides used as templates 2,4-dichlorophenoxyacetic acid (2,4-D) or 4-chloro-2-methylphenoxy- acetic acid (MCPA) were synthesized by precipitation polymerization technique using 4-vinylpyridine (4-VP) as a functional monomer, ethylene glycol dimethacrylate (EGDMA) as a cross-linking agent, and 2,2'-azobisisobutyronitrile (AIBN) as an initiator in methanol solvent. For the flavonoid MIPs, rutin (Ru) and quercetin (Q) were used as templates and synthesized via a similar technique, utilizing acrylamide (AA) as a functional monomer. Analysis of binding in the molecularly imprinted and non-imprinted polymer (NIP) has proved that MIP shows a higher affinity towards the analytes, compared to NIP. MIP was used to determine analytes in water using the Flowing Atmospheric-Pressure Afterglow Mass Spectrometry (FAPA-MS) technique. In this approach, the method limit of detection (MLOD) of 2,4-D, MCPA, Ru, and Q in MIP was 4, 3, 10, and 5 μg in 1 g MIP, respectively. The release kinetics of the analytes from MIP and their stability in water was studied. The cultures of Tetradesmus obliquus (Turpin) M.J. Wynne and Daphnia magna Straus were used for in vivo toxicity studies revealing that only Ru-MIP and Q-MIP had negative effect on the living organisms used in the bioassays.

An Update on Molecularly Imprinted Polymer Design through a Computational Approach to Produce Molecular Recognition Material with Enhanced Analytical Performance

Molecularly imprinted polymer (MIP) computational design is expected to become a routine technique prior to synthesis to produce polymers with high affinity and selectivity towards target molecules. Furthermore, using these simulations reduces the cost of optimizing polymerization composition. There are several computational methods used in MIP fabrication and each requires a comprehensive study in order to select a process with results that are most similar to properties exhibited by polymers synthesized through laboratory experiments. Until now, no review has linked computational strategies with experimental results, which are needed to determine the method that is most appropriate for use in designing MIP with high molecular recognition. This review will present an update of the computational approaches started from 2016 until now on quantum mechanics, molecular mechanics and molecular dynamics that have been widely used. It will also discuss the linear correlation between computational results and the polymer performance tests through laboratory experiments to examine to what extent these methods can be relied upon to obtain polymers with high molecular recognition. Based on the literature search, density functional theory (DFT) with various hybrid functions and basis sets is most often used as a theoretical method to provide a shorter MIP manufacturing process as well as good analytical performance as recognition material.

A novel molecularly imprinted electrochemiluminescence sensor based on cobalt nitride nanoarray electrode for the sensitive detection of bisphenol S

A substitute for bisphenol A (BPA), bisphenol S (BPS) has endocrine disruptive and toxic effects and could pose potential risk on human health and the environment. Herein, we fabricated a sensitive molecularly imprinted electrochemiluminescence (MIECL) sensor for the determination of BPS. CoN nanoarray with outstanding electrical conductivity was prepared and it directly served as the sensor platform. Especially, due to the high surface area of the porous CoN nanoarray, the ECL probe of Ru(bpy)3 2+ could be absorbed on the electrode. By means of the cation exchange of Nafion membrane and utilizing tripropylamine (TPrA) as co-reactant, boosted ECL signals were obtained. Meanwhile, by combining with molecularly imprinted polymers (MIPs), the constructed sensor achieved specific recognition of BPS. On the basis of the superior properties of the CoN nanoarray-based electrode, the ECL signal of the proposed sensor was linearly proportional to the BPS concentration from 2.4 × 10-9 to 5.0 × 10-5 mol L-1 (R 2 = 0.9965) with a low limit of detection (LOD) of 8.1 × 10-10 mol L-1 (S/N = 3). To test the accuracy of the proposed method, the HPLC method was adopted to analyze drinking water samples as a comparison. The t-test result proved that discrepancies between HPLC analysis and the method using the fabricated MIECL sensor were acceptable. The developed MIECL sensor with the sensitive, selective, reproducible, and stable analytical performance provides a potential pathway for the detection of BPS and other BPA substitutes in drinking water samples.

Preparation of monodisperse, restricted-access, media-molecularly imprinted polymers using bi-functional monomers for solid-phase extraction of sarafloxacin from complex samples

Monodisperse restricted-access media bi-functional monomers with molecularly imprinted polymers (RAM-MIPs) were constructed using surface-initiated atom transfer radical polymerization. They were used as solid-phase extraction (SPE) adsorbents to enrich sarafloxacin (SAR) residues from egg samples, and influences on their performance were investigated. Optimum synthesis of RAM-MIPs was achieved by combining a bi-functional monomer (4-vinylpyridine-co-methacrylic acid, 1:3) with an 8:1:32:8 ratio of a template molecule, cross-linker, and restricted-access functional monomer. The SAR imprinting factor of RAM-MIPs was 6.05 and the selectivity coefficient between SAR and other fluoroquinolones was 1.86-2.64. Compared with traditional MIPs, the RAM-MIPs showed better SAR enrichment and selectivity during extraction of a complex protein-containing solution. Empty SPE cartridges were filled with RAM-MIP microspheres as SPE adsorbents. The limit of quantitation for SAR was 4.23 ng g^-1 (signal-to-noise ratio = 10) and the mean SAR recovery from spiked egg samples was 94.0-101.3%. Intra-day and inter-day relative standard deviations were 1.1-9% and 1.5-3.3%, respectively.

Selective solid-phase extraction of four phenylarsonic compounds from feeds, edible chicken and pork with tailoring imprinted polymer

The novel molecularly imprinted microspheres for four phenylarsonic compounds have been firstly prepared with the reversible addition-fragmentation chain transfer polymerization in a suspension system. The resulting polymeric microspheres were characterized by infrared spectrum, scanning electron microscope and differential scanning calorimetry. With serial adsorption experiments, the polymeric microspheres showed highly specific molecular recognition, fast mass transfer rate and robust adsorption of the substrates. Then, the imprinted polymer was used as the solid-phase extraction adsorbent to extract the phenylarsonic compounds from the feeds, edible chicken and pork. The cartridge was washed with 2 mL ethyl acetate and eluted with 3 mL of methanol- acetic acid (90:10, v/v). The recoveries of the molecularly imprinted solid-phase extraction (MISPE) column ranged from 83.4% to 95.1%. This work provided a versatile approach for the specific extraction of the organoarsenic compounds from complicated matrices and exhibited a bright future for the application of MISPE column.

Rapid isolation and determination of bisphenol A in complicated matrices by magnetic molecularly imprinted electrochemical sensing

Because of its widespread distribution in the environment, bisphenol A (BPA) has become a global concern as an endocrine disruptor and a threat to human health through the food chain. Thus an efficient determination method is urgently needed for monitoring the levels of BPA. Herein, a novel electrochemical technique for the detection of BPA was performed by synchronous extraction and pre-concentration of BPA onto magnetic molecularly imprinted polymer (BMMIP), with subsequent readout on a magneto-actuated glassy carbon electrode (MGCE) by differential pulse voltammetry. Compared to the current methods of BPA determination, this BMMIP-based electrochemical sensor (BMMIPs@MGCE) not only simplifies the sample handling procedures substantially, without filtration, centrifugation, or other complex operations, but also can be easily renewed by a controllable magnetic field. As a sensor component, the core-shell BMMIPs exhibited excellent binding capacity (Q_e = 82.5 mg g^-1), short adsorption equilibrium time (30 s), and outstanding selectivity (k' = 7.239) towards BPA, as well as stability and recyclability. Importantly, the BMMIPs@MGCE sensor was successfully applied for the on-site monitoring and rapid detection of BPA in complicated real-world specimens, with good recoveries (81.31-119.77%) and a low limit of detection (0.133 μmol L^-1). Therefore, the stable and low-cost BMMIPs@MGCE sensor provides a new approach for the rapid determination of BPA in the field of environmental control and food safety. Graphical abstract.

Synthesis and characterization of magnetic molecularly imprinted polymers for effective extraction and determination of kaempferol from apple samples

The specific of magnetic molecularly imprinted polymers (Fe3O4@SiO2-MIPs) for kaempferol were fabricated by using acrylamide (AM) as the functional monomer, azobisisobutyronitrile (AIBN) as the initiator and ethylene glycol dimethacrylate (EGDMA) as the cross-linker. The Fe3O4@SiO2-MIPs showed high adsorption capacity (3.84 mg/g) for kaempferol, and the adsorption equilibrium was achieved within 50 min. The specific recognition capacity of Fe3O4@SiO2-MIPs was 3.02 times as high as that of Fe3O4@SiO2-NIPs. The Fe3O4@SiO2-MIPs showed high selectivity towards kaempferol over structural analogues. The recoveries of proposed method at three spiked levels analysis were ranged from 90.5% to 95.4% with the relative standard deviations (RSD) less than 5%. The obtained Fe3O4@SiO2-MIPs were successfully applied for the extraction and determination of kaempferol from apple samples. The established method was simple and feasible, which showed high selectivity, fast separation and satisfactory recoveries for real sample analysis.

Preparation of Chitosan Molecularly Imprinted Polymers and the Recognition Mechanism for Adsorption of Alpha-Lipoic Acid

Two effective molecularly imprinted polymers for the adsorption of alpha-lipoic acid (ALA) were synthesized by the cross-linking of chitosan with epichlorohydrin (ECH) and glutaraldehyde (GLU), respectively, in the presence of ALA as template molecules. Investigations on the molar ratios of ALA and chitosan (–NH₂) in the preparation of chitosan molecularly imprinted polymers (MIPs) were carried out with a factor of ALA rebinding capabilities. The surface morphology and chemical properties of the polymers were characterized. The optimized MIPs crosslinked by ECH (MIPs–ECH) and MIPs crosslinked by GLU (MIPs–GLU) had adsorption capabilities of 12.09 mg/g and 19.72 mg/g for ALA, respectively. The adsorption behaviors of two kinds of chitosan MIPs including adsorption kinetics and isotherms were investigated in detail. Adsorption and kinetic binding experiments showed that the prepared MIPs–ECH and MIPs–GLU had selective adsorption and excellent affinity for ALA. In addition, the possible binding models between ALA and chitosan oligosaccharide were predicted by molecular dynamics simulation.

Molecularly imprinted electrospun nanofibers for adsorption of 2,4-dinitrotoluene in water

2,4-Dinitrotoluene molecularly imprinted nanofibers fabricated by a simple electrospinning technique show higher adsorption capacity and possess remarkable stability and reusability.

Biomimetic insulin-imprinted polymer nanoparticles as a potential oral drug delivery system

In this study, we investigate molecularly imprinted polymers (MIPs), which form a three-dimensional image of the region at and around the active binding sites of pharmaceutically active insulin or are analogous to b cells bound to insulin. This approach was employed to create a welldefined structure within the nanospace cavities that make up functional monomers by cross-linking. The obtained MIPs exhibited a high adsorption capacity for the target insulin, which showed a significantly higher release of insulin in solution at pH 7.4 than at pH 1.2. In vivo studies on diabetic Wistar rats showed that the fast onset within 2 h is similar to subcutaneous injection with a maximum at 4 h, giving an engaged function responsible for the duration of glucose reduction for up to 24 h. These MIPs, prepared as nanosized material, may open a new horizon for oral insulin delivery.

A simple extraction method for norfloxacin from pharmaceutical wastewater with a magnetic core–shell molecularly imprinted polymer with the aid of computer simulation

The best functional monomer was screened using computer simulation. Interaction mechanism between MMIP and norfloxacin was explained using pH optimization and zeta potential detection.

A novel molecularly imprinted method with computational simulation for the affinity isolation and knockout of baicalein from Scutellaria baicalensis

A novel molecularly imprinted polymer (MIP) was synthesized by precipitation polymerization with baicalein (BAI) as the template and used as solid-phase extraction (SPE) adsorbent, aiming at the affinity isolation and selective knockout of BAI from Scutellaria baicalensis Georgi (SB). We used computational simulation to predict the optimal functional monomer, polymerization solvent and molar ratio of template to functional monomer. Characterization and performance tests revealed that MIP exhibited uniform spherical morphology, rapid binding kinetics, and higher adsorption capacity for BAI compared with nonimprinted polymer (NIP). The application of MIP in SPE coupled with high-performance liquid chromatography to extract BAI from SB showed excellent recovery (94.3%) and purity (97.0%). Not only the single BAI compound, but also the BAI-removed SB extract was obtained by one-step process. This new method is useful for isolation and knockout of key bioactive compounds from herbal medicines.

Bio-mimetic sensors based on molecularly imprinted membranes

An important challenge for scientific research is the production of artificial systems able to mimic the recognition mechanisms occurring at the molecular level in living systems. A valid contribution in this direction resulted from the development of molecular imprinting. By means of this technology, selective molecular recognition sites are introduced in a polymer, thus conferring it bio-mimetic properties. The potential applications of these systems include affinity separations, medical diagnostics, drug delivery, catalysis, etc. Recently, bio-sensing systems using molecularly imprinted membranes, a special form of imprinted polymers, have received the attention of scientists in various fields. In these systems imprinted membranes are used as bio-mimetic recognition elements which are integrated with a transducer component. The direct and rapid determination of an interaction between the recognition element and the target analyte (template) was an encouraging factor for the development of such systems as alternatives to traditional bio-assay methods. Due to their high stability, sensitivity and specificity, bio-mimetic sensors-based membranes are used for environmental, food, and clinical uses. This review deals with the development of molecularly imprinted polymers and their different preparation methods. Referring to the last decades, the application of these membranes as bio-mimetic sensor devices will be also reported.

A review on plant-based rutin extraction methods and its pharmacological activities

ETHNOPHARMACOLOGICAL RELEVANCE

Rutin is a common dietary flavonoid that is widely consumed from plant-derived beverages and foods as traditional and folkloric medicine worldwide. Rutin is believed to exhibit significant pharmacological activities, including anti-oxidation, anti-inflammation, anti-diabetic, anti-adipogenic, neuroprotective and hormone therapy. Till date, over 130 registered therapeutic medicinal preparations are containing rutin in their formulations. This article aims to critically review the extraction methods for plant-based rutin and its pharmacological activities. This review provides comprehensive data on the performance of rutin extraction methods and the extent of its pharmacological activities using various in vitro and in vivo experimental models.

MATERIALS AND METHODS

Literatures including journals, patents, books and leaflets reporting on rutin from natural resources are systematically reviewed, particularly in the aspect of its extraction methods and biological activities. Factors affecting the efficiency of rutin extraction such as extraction temperature, duration and solvent to sample ratio are presented based on the findings of previous studies. The observed biological activities followed by clear explanation are also provided accordingly.

RESULTS

The biological activities of rutin varied largely dependent on the geographical and plant origins. The complexity of natural rutin has impeded the development of rutin derived drugs. The detail mechanism of rutin in human body after consumption is still unclear. Therefore, studies are intensively carried out both in vitro and in vivo for the better understanding of the underlying mechanism. The studies are not limited to the pharmacological properties, but also on the extraction methods of rutin. Many studies have focused on the optimization of extraction method to increase the extraction yield of rutin. Currently, the performances of modern extraction approaches have also been compared to the conventional heat reflux method as a benchmark.

CONCLUSION

There are various extraction methods for plant-based rutin ranging from conventional method up to the use of modern techniques such as ultrasound, mechanochemical, microwave, infrared and pressurized assisted methods. However, proper comparison between the methods is very difficult because of the variance in plant origin and extraction conditions. It is important to optimize the extraction method in order to produce high yield and acceptable purity of rutin with a reasonable cost. Even though rutin has been proven to be effective in numerous pharmacological activities, the dosage and toxicity of rutin for such activities are still unknown. Future research should relate the dosage and toxicity of rutin for the ethnobotanical claims based on the underlying mechanisms.