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Molecularly imprinted polymers demonstrate outstanding performance in the research on trace ingredients because of their high selectivity. Stimuli-responsive molecularly imprinted polymers(STR-MIPs) with the introduction of different responsive groups on the basis of traditionally imprinted materials can undergo reversible transformations when exposed to external stimuli such as temperature, magnetism, pH or light. Such responsiveness, combined with the specific recognition, endows STR-MIPs with excellent perfor-mance in trace component studies. Traditional Chinese medicine(TCM) contains complex components with trace content, and thus STR-MIPs have broad application prospects in the enrichment analysis of trace components in TCM. This paper elaborates on the application of STR-MIPs in the enrichment analysis of trace components in TCM from the perspectives of different stimuli, summarized relevant research achievements in the recent five years to broaden the application fields of molecular imprinting, and proposed a few opi-nions about their future development.
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Antibiotics are a category of chemical compounds used to treat bacterial infections and are widely applied in cultivation,animal husbandry,aquaculture,and pharmacy.Currently,residual antibiotics and their metabolites pose a potential risk of allergic reactions,bacterial resistance,and increased cancer incidence.Residual antibiotics and the resulting bacterial antibiotic resistance have been recognized as a global challenge that has attracted increasing attention.Therefore,monitoring antibiotics is a critical way to limit the ecological risks from antibiotic pollution.Accordingly,it is desirable to devise new analytical platforms to achieve efficient antibiotic detection with excellent sensitivity and specificity.Quantum dots(QDs)are regarded as an ideal material for use in the development of antibiotic detection biosensors.In this review,we characterize different types of QDs,such as silicon,chalcogenide,carbon,and other doped QDs,and summarize the trends in QD-based antibiotic detection.QD-based sensing applications are classified according to their recognition strategies,including molecularly imprinted polymers(MIPs),aptamers,and immunosensors.We discuss the advantages of QD-derived antibiotic sensors,including low cost,good sensitivity,excellent stability,and fast response,and illustrate the current challenges in this field.
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In recent years, the overexpression dopamine (DA) due to the use of addictive drugs has caused concern and urgently needs to be addressed. The method used in our study is known as biomimetic sol-gel synthesis. We undertook the experiment to develop molecularly imprinted xerogel polymers (MIXPs) through template molecules dopamine polymerized with polyethyleneimine (PEI), then self-assembled and crosslinked with tetramethoxysilane (TMOS) in the form of non-covalent hydrogen bonds by using biomimetic sol-gel process, and then eluted template DA will leave a blotting site. Monoamine oxidase immobilized MIXPs (MAO-MIXPs) was obtained by coating monoamine oxidase onto MIXPs. The synthesis optimization of MAO-MIXPs was finally set as the ratio of DA template, PEI and MAO coating (DA 40 mg, PEI 0.6 mL, MAO 2.5 mg·g-1) to achieve highly selective adsorption toward DA in artificial cerebrospinal fluid based on the adsorption performance and degradation performance. The micromorphologies and physical-chemical properties of MAO-MIXPs were characterized by scanning electron microscopy, differential scanning calorimeter and Fourier transform infrared spectroscopy, and then amount of adsorption was calculated with adsorption equation. Simultaneously, the Brunner-Emmet-Teller (BET) and Langmuir model were simulated. It was found that the adsorption behavior tended to be monolayer adsorption. This new molecularly imprinted polymer demonstrated potential dopamine expression regulation for highly selective recognition, adsorption and degradation of dopamine.
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The dummy template molecularly imprinted polymers not only has such characteristics of normal imprinted polymers as rapid identification, easy preparation, stable structure and multiple reuse, but also can imprint the compounds in natural products that are not suitable as direct template. Therefore, it has drawn more and more attention in the field of the study of natural products. This paper summarizes the methods for the selection of dummy template molecules by investigating the relevant literatures in the past ten years, analyzes the advantages and disadvantages of dummy template molecules in the practical application, and based on the types of natural products active ingredients, this paper is the first to review of the latest progress in extraction and separation of dummy template molecularly imprinted polymers. We believed that this paper could provide references for better applications of the dummy template molecularly imprinted polymers to extract and separate natural products.
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Produtos Biológicos/química , Fracionamento Químico , Impressão Molecular , PolímerosRESUMO
objective To develop a new method for the adsorption and separation of ginkgolic acid (GA). Methods Using salicylic acid (SA) as a dummy template and 4-vinylpyridine as the functional monomer, molecularly imprinted polymer (MIP) with high adsorbability to GA was synthesized by molecular self-assembly technique. The imprinting mechanism of the polymers was studied by 1H-NMR and IR spectra, and the structure of the polymers was characterized by SEM. The structure of the polymer was analyzed by FT-IR and the adsorption and binding properties of the polymer to total GA were analyzed by HPLC and UV detection. Results MIP had better three-dimensional space structure and adsorption properties. Template molecules were binded to functional monomers with noncovalent bonds. The adsorption rate of GA by polymer MIP in the extract of Ginkgo biloba was 95.9%. The Scatchard analysis reveals that there were two different recognition sites in MIP in the extract of G. biloba, and the apparent maximal combination amount (Qmax1) was 30 mg/g in high affinity recognition sites and with (Qmax2) = 80 mg/g in low affinity recognition sites. And the adsorption kinetics can be best described as the pseudo-second-order kinetics model. Conclusion The preparation of MIP with SA as dummy template has strong adsorption properties for GA, which has a good prospect of popularization and application in the separation and purification of GA.
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Objective: To prepare the molecularly imprinted composite membrane of curcumin by the atom transfer radical polymerization (ATRP) technique and develop a method for the separation and enrichment of curcumin in actual samples. Methods Curcumin MIM were prepared by thermal polymerization method using curcumin as template molecule, methylacrylic acid as functional monmers, cuprous chloride as catalyst, pentamethyldiethylenetriamine as ligand, and polyvinylidene fluoride as base membrane. The microstructure of MIM was investigated by SEM. The maximum adsorption and adsorption equilibrium time of MIM were investigated by static and dynamic adsorption experiment, and the selective penetration capacity was studied. The MIM as membrane material of osmotic device combined with HPLC was used for separation, enrichment and determination of curcumin in samples. Results The results showed that the prepared curcumin MIM had a regular distribution of pores and a uniform size. The maximum adsorption capacity was 3.81 mg/g, and the adsorption equilibrium could be achieved in 15 min. In the selective permeation process of ferulic acid, quercetin and curcumin, MIM had a high selective permeability to curcumin. The average recovery rates of curcumin in ginger, turmeric and curry were (94.100 ± 3.952)%, (98.300 ± 3.637)%, and (97.900 ± 3.133)%, respectively. The RSD was less than 4.2%. The limit of detection was 1.76 μg/kg. Conclusion The prepared MIM is a new material for strong selectivity, separation and enrichment of Chinese medicine curcumin with fast adsorption speed. At the same time, it also provides reference for chemical composition research of other Chinese materia medica.
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p-Hydroxybenzoic acid can be oxidized by hydroxyl radicals ( · OH) to produce electroactive 3,4-dihydroxybenzoic acid (3,4-DHBA). Therefore, it can be used as a probe to detect ·OH. In this work, 3,4-DHBA/ PPy / TiO2 molecularly imprinted polymer film was prepared for indirect determination of ·OH based on its recognition ability for 3,4-DHBA. The sensor was constructed by using pyrrole as the functional monomer and 3, 4-DHBA as the template molecule. The sensor was characterized by scanning electron microscope and different electrochemical methods. The preparation and determination conditions, such as the electropolymerization cycle number, pH value in the electropolymerization process, and elution time, were optimized. Under the optimal conditions, a linear range of 1. 0×10-8-1. 0×10-6 mol/ L was obtained for 3,4-DHBA and the detection limit was down to 4. 2×10-9 mol/ L (S / N = 3). This new approach was of low cost and convenience, and was successfully applied to measure the concentration of ·OH in the atmosphere.
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An ultra performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) method was developed for the determination of 11 kinds of aminoglycosides (AGs), including paromomycin, spectinomycin, tobramycin, gentamycin, kanamycin, hygromycin B, apramycin, streptomycin, dihydrostreptomycin,amikacin and neomycin in aquatic products. Samples were extracted by phosphate buffer solution, and purified on molecularly imprinted polymers (MIP) solid phase extraction column. After separated by Obelisc R chromatographic column, AGs were detected by UPLC-MS/MS. It showed a good linearity relationship in the AGs concentration range of 1.0-1000 ng/mL with the correlation coefficient R2>0.994. The limit of detection (LOD,S/N≥3) was ranged from 1.0 μg/kg to 10.0 μg/kg,and the limit of quantitation (LOQ,S/N≥10) was ranged from 2.0 μg/kg to 20.0 μg/kg. Besides, the average recoveries presented 78.4%-109.6% with the relative standard deviation (RSD, n=6) of 2.3%-14.9%. This method was successfully applied to the simultaneous determination of 11 kinds of AGs with high sensitivity in aquatic products.
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Magnetic molecularly imprinted polymers(MMIPs) were prepared with ZL006 as template, acrylamide(AA) as the functional monomer, and acetonitrile as pore-forming agent; then Fourier transform infrared spectroscopy(FT-IR) and scanning electron microscopy(SEM) were used to characterize their forms and structures. Simultaneously, the MMIPs prepared previously were used as sorbents for dispersive magnetic solid phase extraction(DSPE) to capture and identify potential nNOS-PSD-95 uncouplers from extracts of Trifolium pratense and the the activities of the screened compounds were evaluated by the neuroprotective effect and co-immunoprecipitation test. The experiment revealed that the successfully synthesized MMIPs showed good dispersiveness, suitable particle size and good adsorption properties. Formononetin, prunetin and biochanin A were separated and enriched from Trifolium pratense by using the MMIPs as artificial antibodies and finally biochanin A was found to have higher cytoprotective action and uncoupling action according to the neuroprotective effect and co-immunoprecipitation test.
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Adsorção , Genisteína , Química , Impressão Molecular , Compostos Fitoquímicos , Química , Polímeros , Química , Extração em Fase Sólida , Espectroscopia de Infravermelho com Transformada de Fourier , Trifolium , QuímicaRESUMO
A molecular imprinting polymer technique was successfully applied to precipitation polymerization by using styrene as a functional monomer, curcuminoids as templates, acetonitrile as a porogenic solvent, benzoyl peroxide as the initiator, and ethylene glycol dimethacrylate as the crosslinker. The effects of interaction on the adsorption capacity of the molecularly imprinted polymer (MIP) and non-imprinted polymer (NIP) were investigated. A comparison of the adsorption capacity for MIP and NIP indicated that the NIP had the lowest adsorption capacity. The curcuminoid-imprinted polymer (Cur-MIP) was syn-thesized from 0.0237 mmol of styrene, 47.0 g of acetonitrile, 1.0238 mmol of ethylene glycol dimetha-crylate, 0.0325 mmol of curcuminoids, and 0.2480 mmol of benzoyl peroxide. A high-performance liquid chromatography method with fluorescence detection was developed and validated for various chro-matographic conditions for the determination of the curcuminoids in turmeric samples. The sample solution was separated using the Cur-MIP via solid-phase extraction and analyzed on a Brownlee ana-lytical C18 column (150 mm × 6 mm, 5μm) using an isocratic elution consisting of acetonitrile and 0.1%trichloroacetic acid (40:60, v/v). The flow rate was maintained at 1.5 mL/min. The fluorescence detector was set to monitor atλex = 426 nm andλem = 539 nm. The quantification limit values were found to be 16.66, 66.66, and 33.33μg/L for curcumin, demethoxycurcumin, and bisdemethoxycurcumin, respec-tively. Thus, we concluded that the Cur-MIP and high-performance liquid chromatographic-fluorescence method could be applied to selective extraction and could be used as a rapid tool for the determination of curcuminoids in medicinal herbal extracts.
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Objective To develop a novel strategy for separation and purification of target protein by magnetic molecularly imprinted nanoparticles . Methods Fe3 O4 nanoparticles were synthesized through a hydrothermal method .A sol-gel technique was adopted to prepare imprinting layers .The adsorption capability of magnetic molecularly imprinted nanoparticles was investigated by kinetic , isothermal , and selective binding experiments .Results The imprinted nanomaterials could reach equilibrium within 30 min . The adsorption capacity was 44 .51 mg/g .The imprinting factor and selectivity coefficient were 3 .50 and 2 .92 ,respectively .The resulting imprinted polymers could selectively separate and enrich bovine hemoglobin from a bovine blood sample . Conclusion The prepared imprinted nanomaterials with good specific adsoprtion ability can provide an effective strategy for separation and purification of target protein .
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The magnetic molecularly imprinted polymers ( MMIPs ) was synthesiZed by suspension polymers technique using ornidaZole ( ONZ) as template, and methacrylic acid ( MAA) and acrylamide ( AA) as the binary functional monomers.The MMIPs were characteriZed by means of scanning electron microscopy ( SEM ) , Fourier transform infrared spectroscopy ( FT-IR ) , vibrating sample magnetometer ( VSM ) , thermogravimetric analysis ( TGA) and ultraviolet-visible ( UV-Vis) spectrophotometer.The results indicated that the adsorption capacity of MMIPs using the binary functional monomers to ONZ was higher than that using single functional monomer or that of its structural analogues.The Scatchard plot revealed that the template polymer system had a two-site binding behavior and the MMIPs exhibited the maximum rebinding to ONZ at 48.96 μmol/g and 10.60 μmol/g.Combined with high performance liquid chromatographic analysis technology, the prepared MMIPs were successfully applied to extract and enrich trace nitroimidaZoles from river water samples with recoveries range of 85.4%-104.3%.The precision of the results was good, and the manipulation of the developed method was simple and fast comparing to other methods.
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To improve the sensitivity of molecularly imprinted electrochemical sensors, a Pd nanoparticles-modified molecularly imprinted polymer (MIP) film for the determination of trimethoprim (TMP) was developed by thermal polymerization with N, N′-methylene diacrylamide as a functional monomer, Pd nanoparticle as a dopant and ethylene glycol maleic rosinate acrylate as a crosslinking agent.The morphologies and chemical structures of the Pd nano-materials and the imprinted films were characterized using Fourier transform infrared spectroscopy and scanning electron microscopy, respectively.The electrochemical properties of the nano-doped and undoped MIP sensors were investigated by cyclic voltammetry and electrochemical impedance spectroscopy.Results showed that the morphologies and chemical structures and the electrochemical properties of the doped molecularly imprinted sensor were remarkably different from those of the undoped imprinted sensor.Linear responses of the imprinted sensor to TMP were observed for concentrations ranging from 5.0×10-7 mol/L to 4.0×10-3 mol/L (R=0.9995), with a detection limit of 3.2×10-8 mol/L (S/N=3).The Pd nanoparticle doped MIP sensors exhibited high selectivity.The chronoamperometry showed that no interference from potential interfering species such as sulfamethoxazole, sulfadiazine, glucose, and urea were noted.The proposed electrochemical sensor was used to determine TMP in actual samples, with average recoveries of 96.8%-102.0%.
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Molecular simulation was used to study the interaction between template molecule and functional monomer to shorten the optimization time for the functional monomer and the ratio of functional monomer and template molecule.Kaempferol molecularly imprinted polymerization (MIP) monolithic column was therefore synthesized by reversible addition-fragmentation chain-transfer (RAFT) polymerization with dibenzyltrithiocarbonate (DBTTC) and ethyleneglycoldim ethacrylate (EDMA) as RAFT and cross-linking agent, respectively, whereas methacrylic acid (MAA) was the optimal functional monomer with the molar ratio of kaempferol/MAA of 1∶4 from molecular simulation results.The results indicate that molecular simulation is useful to simplify the experimental procedure, and DBTTC as RAFT agent can provide more adjustable and better MIP monolithic column.
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The magnetic molecularly imprinted polymers (MMIPs), based on the surface of magnetic nanoparticles being modified by surface grafting, have been successfully synthesized, with dibutyl phthalate (DBP) as template molecule, ethylene glycol dimethacrylate (EGDMA) as cross-linking agent and azobisisobutyronitrile (AIBN) as initiator. Scanning electron microscopy (SEM), transmission electron microscope (TEM), and elemental analysis were employed to characterize the MMIPs. The structure and magnetic properties of the MMIPs were investigated by means of X-ray diffraction and vibrating sample magnetometer. The BET surface area shows that MMIPs is 380 m2/g and MNIPs is 324 m2/g. A series of static adsorption experiments were conducted to analyze its adsorption performance, which followed pseudo-second-order model by the kinetic analysis with correlation coefficient (R2) 0.9797, and Sips equation with correlation coefficient (R2) 0.999 by the isothermal analysis. The imprinting factors of diallyl phthalate (DAP), DBP and di-2-ethylhexyl phthalate (DEHP) were 1.53, 2.21 and 1.39 respectively, showing that MMIPs had better recognition performance for DBP. The experiment of regeneration recycles with five times showed the regeneration ability of DBP was only reduced by 12.3％.
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An electrochemical sensor was fabricated for determination of cholesterol ( ChO ) based on the molecularly imprinting and signal amplification of graphene. The sensor was prepared by electropolymerizing phenol on the surface of graphene modified glassy carbon electrode with ChO as template. The structure, properties and molecular imprinting effect of the imprinted membrane were studied by SEM, CV and DPV. The results showed that the sensor had good selectivity and high sensitivity to cholesterol. The calibration graph for the determination of cholesterol was linear in the range of 8. 0 × 10-8-2. 0 × 10-4 mol/L, with the detection limit (S/N=3) of 5. 6×10-8 mol/L. The sensor was applied to the determination of cholesterol in human serum samples with satisfactory results.
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An electrochemical sensor was fabricated for determination of cholesterol ( ChO ) based on the molecularly imprinting and signal amplification of graphene. The sensor was prepared by electropolymerizing phenol on the surface of graphene modified glassy carbon electrode with ChO as template. The structure, properties and molecular imprinting effect of the imprinted membrane were studied by SEM, CV and DPV. The results showed that the sensor had good selectivity and high sensitivity to cholesterol. The calibration graph for the determination of cholesterol was linear in the range of 8. 0 × 10-8-2. 0 × 10-4 mol/L, with the detection limit (S/N=3) of 5. 6×10-8 mol/L. The sensor was applied to the determination of cholesterol in human serum samples with satisfactory results.
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Separation of active ingredients from Chinese materia medica (CMM) by molecularly imprinted polymers has such advantages as high speed, low cost, being reusable, low pollution, and so on. Because of this reason, the synthesis of molecularly imprinted polymers and its application in separation have drawn more and more attention of researchers in the field of CMM all over the world. Obviously, the core of this research is to explore the relationship between the polymer-structure and separation efficiency. Based on the types of active ingredients of CMM (flavone, alkaloids, phenylpropanoids, terpenoids, etc.), the design principle of molecularly imprinted polymer, its preparation methods and latest application in separation of active ingredients from CMM were introduced. Therefore, this paper can provide a reference for designing new materials with higher selectivity in separation of active ingredients from CMM.