Optimization of serotonin imprinted polymers and recognition study from platelet rich plasma

Molecularly imprinted polymers using serotonin as the template molecule was prepared for selective recognition from platelet rich plasma by non-covalent imprinting approach. Four different monomers (methacrylic acid, acrylamide, 4-vinylpyridine and 2-acrylamido-2-methylpropane sulfonic acid) and acetonitrile and DMSO as porogen were investigated for the first time by bulk polymerization. The molecularly imprinted polymer which was prepared by acrylamide/methacrylic acid had the largest imprinting factor for serotonin. The affinity and specificity of these polymers were evaluated by equilibrium binding experiments. The effect of polarity of the solvents was examined by polymers binding capacity and imprinting factor. According to the Scatchard analysis the K(d) and Q(max) values were calculated as 1.95 micromoll(-1) and 19.129 micromolg(-1), respectively. The polymer was tested to evaluate serotonin from platelet rich plasma and 70% serotonin recovery was found.     

Synthesis and study of sorption properties of molecularly imprinted polymers for quercetin

Molecularly imprinted polymers for quercetin and the corresponding nonimprinted blank polymers (control polymers) have been synthesized using acrylamide and 2-(dimethylamino)-ethylmethacrylate as functional monomers. It has been shown that the nature of the template, the ratio of the functional monomer to template within the prepolymerization mixture, and the amount of crosslinker, which were varied at the synthesis stage, influenced on the sorption properties of molecularly imprinted polymers for quercetin. Synthesis conditions were optimized by varying the composition of the prepolymerization mixture. The sorption properties of the obtained materials have been studied. The estimation of selectivity of a sorbent with the imprints of quercetin was carried out by the example of structurally related compounds. It has been shown that the acrylamide-based polymer was able to selectively sorb quercetin, the binding sites of the quercetin being mainly of hydrophobic structure.     

复合分子印迹聚合物体系选择性富集蛋白质样品中的溶菌酶

考察了功能单体与模板蛋白的反应摩尔比、溶液pH值及离子强度对功能单体与模板蛋白之间相互作用的影响, 得出制备分子印迹聚合物的最佳条件. 在最佳条件下, 以溶菌酶(Lyz)为模板分子, 丙烯酰胺(AA)和N,N’-亚甲基双丙烯酰胺(BisAA)为聚合基质, 二氧化硅为固体制孔剂, 制备了复合分子印迹聚丙烯酰胺凝胶, 并用平衡吸附实验研究了其吸附性能和识别选择性. 研究结果表明, 该聚合物对模板蛋白有较高的亲和性、选择性和吸附容量,可以从蛋白质混合溶液中分离富集模板分子.     

Sulfonamide imprinted polymers using co-functional monomers

Molecular imprinted polymers (MIPs) prepared using combination of acrylamide (ACM) and 4-vinylpyridine (4-Vpy) as co-functional monomers exhibited efficient recognition properties in both organic and aqueous media as HPLC stationary phase. The results indicate that amide and pyridine groups in functional monomers formed strong hydrogen-bonding interaction with the template molecule, and specific recognition sites were created within the polymer matrix during the imprinting process. When sulfamethoxazole (SMO) was used as template, a MIP prepared in a polar organic solvent (acetonitrile) using the combination of ACM and 4-Vpy showed better recognition of template than the polymer prepared in the same solvent using the combination of acidic monomer (methacrylic acid) and basic monomer 4-Vpy. On the contrary, when sulfamethazine (SMZ) was used as template, a MIP prepared using the combination of methacrylic acid (MAA) and 4-Vpy showed better recognition of template than the polymer prepared using the combination of ACM and 4-Vpy. Our results indicate that in organic media the degree of retention of the sample molecules on the imprinted polymers was controlled by the hydrogen-bonding interaction between the sample molecules and the polymer, while in aqueous media it was determined to a considerable extent by hydrophobic interactions. In both media the shape, size and the electronic structure of the template molecule were all-important factors in the recognition process.     

Evaluation of molecularly imprinted membranes based on different acrylic copolymers

Polyacrylonitrile and its copolymers with different functional monomers (itaconic acid, acrylic acid and acrylamide) were synthesized via water-phase precipitation polymerization in order to prepare molecularly imprinted polymer (MIP) membranes with recognition properties for the flavonoid naringin (NR). Membranes were prepared by phase inversion technique using dimethylformamide (DMF) as the solvent and adding naringin as template molecule to the casting solution. For comparison, membranes without template (blank) were prepared and tested. All MIP membranes showed high specific binding capacity; among them, the membrane prepared with the copolymer containing acrylamide as functional group, showed the highest binding capacity. Blank membranes only showed non-specific binding. The bound template was totally recovered and regenerated membranes maintained their initial binding capacity after reuse.     

The effectively specific recognition of bovine serum albumin imprinted silica nanoparticles by utilizing a macromolecularly functional monomer to stabilize and imprint template

Structural stability of the template is one of the most important considerations during the preparation of protein imprinting technology. To address this limitation, we propose a novel and versatile strategy of utilizing macromolecularly functional monomers to imprint biomacromolecules. Results from circular dichroism and synchronous fluorescence experiments reflect the macromolecularly functional monomers tendency to interact with the protein surface instead of permeating it and destroying the hydrogen bonds that maintain the protein’s structural stability, therefore stabilizing the template protein structure during the preparation of imprinted polymers. The imprinted polymers composed of macromolecularly functional monomers or their equivalent micromolecularly functional monomers over silica nanoparticles were characterized and carried out in batch rebinding test and competitive adsorption experiments. In batch rebinding test, the imprinted particles prepared with macromolecularly functional monomers exhibited an imprinting factor of 5.8 compared to those prepared by micromolecularly functional monomers with the imprinting factor of 3.4. The selective and competitive adsorption experiments also demonstrated the imprinted particles made by macromolecularly functional monomers possessed much better selectivity and specific recognition ability for template protein. Therefore, using macromolecularly functional monomers to imprint may overcome the mutability of biomacromolecule typically observed during the preparation of imprinted polymers, and thus promote the further development of imprinting technology.     

沉淀聚合法制备右旋邻氯扁桃酸分子印迹聚合物微球

以右旋邻氯扁桃酸为模板,丙烯酰胺、乙二醇二甲基丙烯酸酯分别为功能单体和交联剂,采用沉淀聚合法制备了分子印迹聚合物微球,讨论了反应介质用量、聚合温度、引发剂的种类和用量对印迹微球的影响。实验表明：分子印迹微球与传统本体聚合法制备的聚合物相比具有更高的特异识别能力,通过Scatchard分析研究了聚合物的选择结合性能,结果表明分子印迹聚合物微球在识别右旋邻氯扁桃酸分子的过程中存枉两类结合位点,而空白聚合物微球只存在一类结合位点。     

内分泌干扰物雌酮分子印迹新型吸附功能材料的制备及其选择性能研究

采用分子印迹本体聚合法,制备了对内分泌干扰物雌酮具有高选择识别能力的分子印迹聚合物。吸附动力学和选择性实验结果表明,与非印迹聚合物相比,印迹聚合物具有较高的吸附容量和吸附速率,对模板分子具有较高的选择性。聚合反应条件对印迹聚合物的吸附和识别性能有重要影响,以丙烯酰胺为功能单体,模板分子、功能单体和交联剂摩尔比为1:3:6,制备的印迹聚合物具有较高的选择和吸附性能。     

Fabrication of an electrochemical sensor based on computationally designed molecularly imprinted polymers for determination of cyanazine in food samples

A computational approach was used for screening functional monomers and polymerization solvent in the rational design of molecularly imprinted polymers (MIPs). It was based on the comparison of the binding energy of the complexes between the template and functional monomers. On the basis of computational results, acrylamide (AAM) and toluene were selected as functional monomer and polymerization solvent, respectively. The MIP, embedded in the carbon paste electrode, functioned as a selective recognition element and pre-concentrator agent for cyanazine determination by using cathodic stripping voltammetric method. The MIP-CP electrode showed very high recognition ability in comparison with NIP-CPE. Some parameters affecting the sensor response were optimized, and then the calibration curve was plotted. A dynamic linear range of 5.0–1000 nM was obtained. The detection limit of the sensor was calculated as 3.2 nM. This sensor was successfully used for cyanazine determination in food samples.     

Molecularly Imprinted Polymers: Compromise between Flexibility and Rigidity for Improving Capture of Template Analogues

New synthetic strategies for molecularly imprinted polymers (MIPs) were developed to mimic the flexibility and mobility exhibited by receptor/enzyme binding pockets. The MIPs were prepared by bulk polymerization with quercetin as template molecule, acrylamide as functional monomer, ethylene glycol dimethacrylate as cross‐linker, and THF as porogen. The innovative grafting of specific oligoethylene glycol units onto the imprinted cavities allowed MIPs to be obtained that exhibit extended selectivity towards template analogues. This synthetic strategy gives promising perspectives for the design of molecular recognition of molecules based on a congruent pharmacophore, which should be of interest for drug development.     

杯芳烃衍生物和丙烯酰胺作为复合功能单体的分子印迹聚合物对海因类化合物的选择性识别研究

以杯[4]芳烃衍生物+丙烯酰胺作为复合功能单体,将其运用到分子印迹技术中,对海因类化合物R-苄基海因进行选择性识别.研究结果表明,由单一的杯[4]芳烃衍生物或丙烯酰胺作为功能单体的分子印迹聚合物对R-苄基海因的选择性均不高,而由杯[4]芳烃衍生物+丙烯酰胺作为复合功能单体的分子印迹聚合物对模板分子具有较高的特异选择性.     

An orthogonal approach to multifunctional molecularly imprinted polymers

[structure: see text] An "orthogonal" approach to molecularly imprinted polymers has been demonstrated using a crown ether derived monomer that does not exhibit cross-reactivity with other functional monomers. This strategy provides multiple functional groups in the binding site of molecularly imprinted polymers (MIPs) without unproductive interactions between functional monomers. The orthogonal functional group system was shown to act cooperatively in MIPs to bind a template with higher selectivity than any of the individual functional monomers alone.     

盐酸强力霉素分子印迹聚合物的制备及分子识别性能

以盐酸强力霉素(DC)为模板分子、甲基丙烯酸为功能单体、乙二醇二甲基丙烯酸酯为交联剂、四氢呋喃(THF)为溶剂.采用本体聚合法制备了DC的分子印迹聚合物.在水溶液中,采用平衡结合方法和Scatchard模型评价了该聚合物的结合特性及识别机理,并考察了DC分子印迹聚合物的选择性吸附能力.结果表明,在所研究的浓度范围内,D...     

Quercetin molecularly imprinted polymers: Preparation, recognition characteristics and properties as sorbent for solid-phase extraction

Molecular imprinted polymers (MIPs) were prepared through thermal polymerization by using quercetin as the template molecule, acrylamide (AA) as the functional monomer and ethylene glycol dimethacrylate (EDMA) as the cross-linker in the porogen of tetrahydrofuran (THF). The synthesized MIPs were identified by both Fourier transform infrared (FTIR) and scanning electron microscope (SEM). Systematic investigations of the influences of key synthetic conditions, including functional monomers, porogens and cross-linkers, on the recognition properties of the MIPs were conducted. Scatchard analysis revealed that the homogeneous binding sites were formed in the polymers. Besides quercetin, two structurally similar compounds of rutin and catechol were employed for molecular recognition specificity tests of MIPs. It was observed that the MIPs exhibited the highest selective rebinding to quercetin. Accordingly, the MIPs were used as a solid-phase extraction (SPE) sorbent for the extraction and enrichment of quercetin in cacumen platycladi samples, followed by HPLC-UV analysis. The application of MIPs with high affinity and excellent stereo-selectivity toward quercetin in SPE might offer a novel method for the enrichment and determination of flavonoid compounds in the natural products.     

Evaluation of new selective molecularly imprinted polymers prepared by precipitation polymerisation for the extraction of phenylurea herbicides

Three different molecularly imprinted polymers (MIPs) have been prepared by precipitation polymerisation using linuron (LIN) or isoproturon (IPN) (phenylurea herbicides) as templates and methacrylic acid (MAA) or trifluormethacrylic acid (TFMAA) as functional monomers. The ability of the different polymers to selectively rebind not only the template but also other phenylurea herbicides has been evaluated. In parallel, the influence of the different templates and functional monomers used during polymers synthesis on the performance of the obtained MIPs was also studied through different rebinding experiments. The experimental binding isotherms were fitted to the Langmuir-Freundlich isotherm allowing to describe the kind of binding sites present in the imprinted polymers under study. It was concluded that TFMAA-based polymer using IPN as template presents the best properties to be used as a selective sorbent for the extraction of phenylurea herbicides.     

Synthesis of stationary phases that provide group recognition for polychlorinated biphenyls by porogenic fragment template imprinting

Molecular recognition based on imprinted polymers results from the polymerization of functional monomers and cross‐linkers in the presence of a target analyte (i.e. template), with subsequent removal of the template to create synthetic binding sites. However, complete removal of the template is difficult to achieve, thereby leading to template leaching, which adversely affects real‐world analytical applications. To overcome this challenge, the present study utilizes porogenic fragment template imprinting techniques to provide an alternative synthetic strategy to generate molecularly imprinted polymers with molecular recognition toward polychlorinated biphenyls. Thereafter, thus‐generated imprinted polymers have been applied as stationary phases in molecularly imprinted solid‐phase extraction for preconcentrating six “indicator polychlorinated biphenyls” in both organic and aqueous media. Recoveries of up to 98.9% (imprinted polymers) versus 73.0% (conventional C₁₈) in an organic phase, and up to 97.4% (imprinted polymers) versus 89.4% (C₁₈) in an aqueous phase have been achieved corroborating the utility of this advanced sorbent material. Finally, porogenic fragment template imprinting strategies have yielded molecularly imprinted polymers that are useful for the quantitative determination of polychlorinated biphenyls in environmental matrices, which provides a low‐cost strategy for tailoring stationary phases that avoid template leaching in applications in solid‐phase extraction as well as liquid chromatography.     

Suppression of background sites in molecularly imprinted polymers via urea-urea monomer aggregation

The molecular imprinting process provides a synthetically efficient route to polymers with tailored recognition properties. However, the binding properties of the templated binding sites are often masked by the more prevalent background binding sites. Therefore, a strategy for reducing the number of background binding sites was developed and evaluated that uses functional monomer aggregation to suppress the formation of background sites. A series of imprinted and non-imprinted polymers was formed using crosslinking urea monomer and were evaluated for their ability to rebind the anionic template, tetrabutylammonium diphenyl phosphate (TBA-DPP). The urea monomer was shown to form linear hydrogen bonded aggregates in solution and in the solid state. Functional monomer aggregation in the polymerization solution was shown to dramatically reduce the numbers of background binding sites by occupying and blocking the urea recognition groups that were not bound to the template molecule. Despite the low aggregation constant of the urea monomer (3.5 M(-1) in chloroform), the number of background sites was reduced by more than 60%. We predict that this strategy of using monomers that aggregate to reduce background binding sites is a general one for MIPs and other types of polymers with tailored recognition properties. The key is to identify self-assembling monomers where the guest binding processes are stronger than the aggregation processes.     

光接枝表面修饰法制备牛血红蛋白的分子印迹微球

聚苯乙烯球载体表面经引发转移终止剂修饰后, 采用光接枝表面印迹方法制备了以牛血红蛋白(BHb)为模板分子、丙烯酰胺为功能单体和N,N′-亚甲基双丙烯酰胺为交联剂的分子印迹聚合物微球(MIP). 进一步采用红外光谱(IR)、扫描电子显微镜(SEM)和元素分析对聚合物微球进行了表征, 证实了载体表面成功地接枝了分子印迹层, 并研究了其吸附性能和分子识别选择性能. 结果表明, 采用光接枝表面修饰法制备的分子印迹微球对模板分子有着很好的吸附容量和识别选择性.     

Computational Design and Fabrication of Enantioselective Recognition Sorbents for L-phenylalanine Benzyl Ester on Multiwalled Carbon Nanotubes Using Molecular Imprinting Technology

Computational strategies have been employed to investigate the influence of the nature of monomers and cross-linker in order to design three dimensional imprinted polymers with selective recognition sites for L-phenylalanine benzyl ester(L-PABE) molecule.Here, computational chemistry methods were applied to screen the molar quantity of functional monomers that interact with one mole of the template molecule. Effects of the nature of functional monomer, cross-linker, and molar ratio were determined computationally using density functional calculations with B3LYP functional and generic 6-31G basis set. Methacrylic acid(MAA) and ethylene glycol dimethacrylate(EGDMA) were used as the functional monomer and crosslinking agent, respectively. L-PABE imprinted polymer layered on multiwalled carbon nanotube(MWCNT) and conventional bulk MIP were synthesised and characterized as well. To investigate the influence of pre-organization of binding sites on the selectivity of L-PABE, respective non-imprinted polymers were also synthesised.MWCNT-MIPs and MIPs exhibited the highest adsorption capacity towards L-PABE. The synthesized polymers revealed characteristic adsorption features and selectivity towards L-PABE in comparison with those of its enantiomer analogues.     

Validation and application of modeling algorithms for the design of molecularly imprinted polymers

In the study, four different semiempirical algorithms, modified neglect of diatomic overlap, a reparameterization of Austin Model 1, complete neglect of differential overlap and typed neglect of differential overlap, have been applied for the energy optimization of template, monomer, and template‐monomer complexes of imprinted polymers. For phosmet‐, estrone‐, and metolcarb‐imprinted polymers, the binding energies of template‐monomer complexes were calculated and the docking configures were assessed in different molar ratio of template/monomer. It was found that two algorithms were not suitable for calculating the binding energy in template‐monomers complex system. For the other algorithms, the obtained optimum molar ratio of template and monomers were consistent with the experimental results. Therefore, two algorithms have been selected and applied for the preparation of enrofloxacin‐imprinted polymers. Meanwhile using a different molar ratio of template and monomer, we prepared imprinted polymers and nonimprinted polymers, and evaluated the adsorption to template. It was verified that the experimental results were in good agreement with the modeling results. As a result, the semiempirical algorithm had certain feasibility in designing the preparation of imprinted polymers.