Molecular imprinting using monomers with solid-state polymerization

Molecular imprinting of two diolefinic compounds with solid-state photopolymerization, 2,5-distyrylpyrazine (DSP) and diethyl p-phenylenediacrylate (EPA), was demonstrated. Solid nanoscale particles of the monomer were produced and deposited onto the surface of a surface acoustic wave (SAW) transducer using the technique known as rapid expansion of supercritical solutions (RESS). The particles were polymerized by UV light in the presence of an alkane template vapor. Both imprinted and non-imprinted devices were tested upon exposure to a variety of alkane vapors in the gas phase. The results demonstrate an enhanced sensitivity to vapors at or below the size of the template. A size exclusion mechanism of recognition is proposed.     

Molecular imprinting of protein by coordinate interaction

In this article,a novel strong interaction by forming complex between bovine serum albumin(BSA) and copper ion was utilized for the preparation of molecular imprinted hydrogel in aqueous solution.Results show that the inclusion of copper ion in preparation can bridge the template BSA and functional monomers together and improve the imprinting effect compared to the polymer made without copper ion added.High selectivity factor and large adsorption capacity are also observed for the obtained BSA-imprinted ...     

Preparation of ferrocyanide-imprinted pyridine-carrying microspheres by surface imprinting polymerization.

Ferrocyanide-imprinted pyridine-carrying microspheres were prepared using ferrocyanide ions as a template.This method is based on a surface imprinting technique from the seed emulsion that consisted of 4-vinylpyridine (functional monomer), styrene, and butyl acrylate and a water mixture polymerization by a radical initiator. The ferrocyanide-imprinted microspheres had about 200 times higher adsorption affinity over the non-imprinted microspheres in ferrocyanide (template) ion adsorption. This imprinted microspheres also adsorbed other tripolyphosphate, pyrophosphate, and phosphate anions much more strongly than the non-imprinted microspheres did, but were not particularly specific in ferrocyanide ion adsorption.     

Molecular imprinting inside dendrimers

Synthetic hosts capable of binding porphyrins have been produced by a mixed-covalent-noncovalent imprinting process wherein a single binding site is created within cross-linked dendrimers. Two synthetic hosts were prepared, using as templates 5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin and 5,10,15,20-tetrakis(3,5-dihydroxyphenyl)porphyrin. These two templates were esterified with, respectively, fourth- and third-generation Fréchet-type dendrons containing homoallyl end-groups. The resulting tetra- and octadendron macromolecules underwent the ring-closing metathesis reaction using Grubbs' Type I catalyst, RuCl(2)(P(C(6)H(5))(3))(2)(CHCH(2)C(6)H(5)), to give extensive interdendron cross-linking. Hydrolytic removal of the porphyrin cores afforded imprinted hosts whose ability to bind porphyrins with various peripheral substituents was investigated by UV-visible spectrophotometric titrations and size exclusion chromatography. The results indicate a high yield of imprinted sites that show high selectivity for binding of porphyrins capable of making at least four hydrogen bonds, but only a moderate degree of shape selectivity.     

Molecular imprinting made easy

A simple method of molecular imprinting is presented that uses a single cross-linking monomer N,O-bismethacryloyl ethanolamine (NOBE) along with template, initiator, and solvent. This formulation eliminates the need for additional functional monomers and empirical optimization of relative ratios of functional monomers, cross-linkers, and template. In fact, utilization of NOBE alone often provides molecularly imprinted polymers (MIPs) with higher performance than MIPs incorporating functional monomer (e.g., methacrylic acid).     

Molecular sensing of 3-chloro-1,2-propanediol by molecular imprinting

A covalent interaction-based molecularly imprinted polymer (MIP) material for 3-chloro-1,2-propanediol (3-MCPD), a post-testicular anti-fertility agent and possible carcinogen and mutagen in food products containing acid-hydrolyzed vegetable proteins, has been successfully fabricated using 4-vinylphenylboronic acid as the functional monomer. Rebinding assay revealed that the binding constant, K_B, for the receptor sites and non-specific sites are 1.93±0.1×10⁴ and 2.74±0.7×10² M⁻¹, respectively. The estimated number of receptor site, B_max, imprinted is 123.3±3 μmol/g of MIP. The MIP material is able to act as a potentiometric chemosensor for 3-MCPD via increase in Lewis acidity of the receptor sites upon reaction of the arylboronic acid with 3-MCPD to form the more acidic arylboronic acid esters. A simple pH glass electrode is sufficient to monitor the analyte-specific rebinding. In unbuffered aqueous media, linear potentiometric response from 0 to 350 ppm of 3-MCPD can be achieved. The MIP-based chemosensing in a soya sauce matrix has also been attempted. It is found that the dynamic range of the potentiometric chemosensing response of the MIP material is much reduced, probably due to the blocking or deactivation of receptor sites by interferents in soya sauces. Nevertheless, the present work demonstrated the feasibility of using MIP-based chemosensors as semi-quantitative analytical tools for screening purposes in quality control of food products.     

Acceleration of the corrosion reaction of magnesium by Fenton reagents

Abstract

Magnesium alloys have attracted increased attention for a variety of applications, chief among which are alternative energy and medical implants. The use of biodegradable implants in the complex system of the human body, in which myriad reactions occur, must consider the potential effects of the body’s natural chemical reactions on implant corrosion rates. The aim of this study was to elucidate the synergistic effects of pure Mg and Mg alloys on the Mg corrosion reaction with reagents that participate in the Fenton reaction. We corroborated our results with six different measurement methods (hydrogen evolution rate [HER], gas chromatography [GC], potentiodynamic polarization, inductively coupled plasma [ICP] spectrometry, Auger electron spectroscopy [AES], and scanning electron microscope [SEM]). The results point out that the corrosion and hydrogen evaluation rates of Mg were elevated by the addition of Fenton reagents, divalent iron and hydrogen peroxide, to a saline solution. In the context of Mg-based alloy medical implant development and use, this observation is significant.     

Molecular imprinting technology in capillary electrochromatography

Molecularly imprinted polymers (MIPs) are tailor-made synthetic polymers with a predetermined selectivity for a given analyte, or group of structurally related compounds, that make them ideal materials for use as stationary phases in affinity chromatography. However, extensive peak broadening and tailing, especially of the more retained compound (normally the template) are often observed. Thus, huge efforts have been made during recent years to use MIPs in capillary electrochromatography, which is inherently a more efficient chromatographic technique than conventional HPLC. Accordingly, this paper gives an overview of the attempts carried out in the recent past to improve the chromatographic performance of MIPs in capillary electrochromatography as well as more recent applications. It is concluded that MIPs are very promising materials for use as selective stationary phases in CEC.     

Oxidative polymerization of ethylenedioxythiophene with Fenton’s reagent by the miniemulsion technique

The polymerization of EDOT to PEDOT in miniemulsion with solid contents up to 10 wt.% is reported by using Fenton’s reagent, horseradish peroxidase type II, or sodium peroxodisulfate, respectively, as initiators. The resulting dispersions contain at most 50 wt.% of surfactant (PSS) with respect to solid and are stable at least for weeks. The structure of the polymers is determined by IR, NMR, and UV/Vis spectroscopy. The doping level can be controlled by adopting the oxidation potential of the initiator system. Spin-coated films from the dispersions show conductivities up to 0.01 S cm⁻¹.     

Molecular imprinting of protein in Pickering emulsion

A new strategy of molecular imprinting to prepare spherical hydrogels via water-in-oil Pickering emulsion polymerization was developed. The imprinted hydrogels exhibited fast adsorption kinetics and significant selectivity for the target protein.     

O2 evolution in the Fenton reaction

We investigated the mechanism involved in the oxygen production in the Fenton chemistry by means of density functional theory calculations. This study extends previous work in which we proposed that the Fe(IV)O2+ complex is the key active intermediate in the Fenton reaction. Here we provide a consistent picture of the entire reaction cycle by analyzing how the active species, Fe(IV)O2+, can react with hydrogen peroxide to produce O2 and regenerate the Fe2+ catalyst. These results are also relevant in view of the analogies with important enzyme-catalyzed oxidation reactions.     

Molecular imprinting for anion recognition in aqueous media

Molecular imprinting technology is an attractive approach of creating recognition sites in polymeric materials by using the templating approach found in many natural systems. These recognition sites have memory to the target molecule that enables selective recognition of the template species. Molecularly imprinted polymers (MIPs) have been used in a wide range of areas including separation and isolation, catalysis, chemical sensing, and drug delivery. This review aims at highlight the recent advances in the application of molecular imprinting technology for inorganic and small organic anion recognition in aqueous media.

Molecular imprinting for removing highly toxic organic pollutants

Molecular imprinting technology allows synthesis of polymers with specific recognition ability towards target pollutants, which show potential to selectively remove Highly Toxic Organic Pollutants (HTOPs) in the presence of common organic matrices that are thousands of times more abundant than the targets. This feature article summarizes the current development of molecular imprinting for removing HTOPs from polluted water, with a special emphasis on the application of molecularly imprinted polymers to improve the efficiency of photocatalytic and biological degradation of HTOPs in wastewater.     

Comparison of binding behavior for molecularly imprinted polymers prepared by hierarchical imprinting or Pickering emulsion polymerization

The aim of this study was the evaluation of the binding performances and selectivity of molecularly imprinted beads prepared toward several penicillins (i) by hierarchical bulk polymerization in the pores of template‐grafted silica microbeads (hMIPs) and (ii) by Pickering emulsion polymerization in the presence of template‐decorated silica nanobeads (pMIPs). 6‐Aminopenicillanic acid was chosen as the common fragmental mimic template. Both approaches produced micron‐sized polymeric beads with good recognition properties toward the target ligands whereas the selectivity pattern appeared quite different. The polymer prepared by the Pickering emulsion approach showed binding properties similar to imprinted beads prepared by hierarchical approach. Equilibrium binding constants changed their values from 0.1–0.2 × 10⁶ (hMIPs) to 0.2–0.6 × 10⁶ M^?1 (pMIPs), while the binding site densities changed from 3.7–4.8 (hMIPs) to 0.3–0.55 μmol/g (pMIPs). Compared to the hierarchical polymerization, Pickering emulsion polymerization represents a more practical approach when a template mimic needs to be used.     

Crystallization during polymerization of diphenylsilylene by a chemical transport reaction

Crystallization during polymerization of polydiphenylsilylene has been accomplished. Best results are obtained by initial thermal polymerization to the amorphous macromolecule. The macromolecules are then decomposed and repolymerized by sublimation. Macroscopic extended-chain single crystals are produced. The polymer crystals, once molten, will not recrystallize. Their initial characterization is described using infrared, Raman, ultraviolet, and nuclear magnetic resonance spectroscopy. X-ray and thermal analysis data are also given.     

Molecular imprinting of peptides and proteins in aqueous media

Molecular imprinting has received significant attention in recent years, as it provides a viable method for creating synthetic receptors capable of selectively recognizing specific target molecules. Despite significant growth within the field, the majority of template molecules studied thus far have been characterized by their low molecular weight and insolubility in aqueous systems. In biological systems, molecular recognition events occur in aqueous media. Therefore, in order to create molecularly imprinted polymers capable of mimicking biological processes, it is necessary to synthesize artificial receptors which can selectively recognize their respective target biological macromolecules such as peptides and proteins in aqueous media. In this review, we discuss the challenges associated with the imprinting of peptides and proteins in aqueous media. In addition, we discuss the significant progress which has been made within the field.     

蛋白质分子印迹技术载体形式的研究进展

现代生物技术产品分离成本很高,分子印迹技术以其优良的操作稳定性为蛋白质分离提纯提供了一种新的方法,合成蛋白质分子印迹聚合物具有巨大的应用价值,又极具挑战性,已成为各国科学工作者们研究的热点。本文对蛋白质分子印迹过程中使用的载体形式进行了综述,对不同形式载体的使用特点进行了总结,详细叙述了常见的载体形式如硅胶、合成树脂球、高分子膜、云母、凝胶以及一些新型的载体类似形式如环糊精和壳聚糖等,并探讨了目前蛋白质分子印迹技术存在的问题及其应用前景。     

Molecular architecture control in acrylic polymers by group transfer polymerization

The living polymerization of methacrylates by a repeated silyl Michael addition reaction (GTP)^a operates at room temperature and permits a high degree of molecular architecture control. Chelic, telechelic, block, comb, star, loop, and ladder polymers have been synthesized. For nucleophilic catalysts other than bifluoride, a dissociative mechanism is now proposed.