Reflux precipitation polymerization : a new synthetic insight in molecular imprinting at high temperature

Synthesis of uniform molecularly imprinted polymer (MIP) microspheres (MSs) using distillation precipitation polymerization (DPP) at high temperature has attracted great interest in the field of molecular imprinting. However,there were still some shortcomings in this method. In this work, to create uniform MIP MSs in a short time and to demonstrate the effects of high temperature on imprinting performance, a new precipitation polymerization method (reflux precipitation polymerization, RPP) was used for the first time to fabricate MIP MSs in this study. The SEM images of the polymeric MSs indicate the presence of template molecules could improve the particle morphology and size uniformity. The specific molecular recognition of the monodispersed MIP MSs was confirmed by fluorescence measurement and HPLC-UV analysis. The binding behavior of the MIP MSs was simulated using the heterogeneous Freundlich isotherm, which shows that the MIP MSs produced by the RPP possess compatible selectivity in comparison with those by traditional PP method. It is noted that, for the first time, we demonstrated that molecular imprinting at high temperature was only successful when electrostatic interactions played important roles in the imprinting process

Interfacial Molecular Imprinting in Nanoparticle-Stabilized Emulsions

A new interfacial nano and molecular imprinting approach is developed to prepare spherical molecularly imprinted polymers with well-controlled hierarchical structures. This method is based on Pickering emulsion polymerization using template-modified colloidal particles. The interfacial imprinting is carried out in particle-stabilized oil-in-water emulsions, where the molecular template is presented on the surface of silica nanoparticles during the polymerization of the monomer phase. After polymerization, the template-modified silica nanoparticles are removed from the new spherical particles to leave tiny indentations decorated with molecularly imprinted sites. The imprinted microspheres prepared using the new interfacial nano and molecular imprinting have very interesting features: a well-controlled hierarchical structure composed of large pores decorated with easily accessible molecular binding sites, group selectivity toward a series of chemicals having a common structural moiety (epitopes), and a hydrophilic surface that enables the MIPs to be used under aqueous conditions

Molecular imprinting in Pickering emulsions: a new insight into molecular recognition in water.

Molecularly imprinted polymer microspheres were synthesized by Pickering emulsion polymerization. Fluorescence spectroscopic investigations provided insights into the template recognition in water

Janus molecularly imprinted polymer particles

By combining the specific molecular recognition capability of MIPs and the asymmetric structure of Janus particles, the Janus MIP particles which were synthesized via a wax-water Pickering emulsion showed attractive capabilities as self-propelled transporters for controlled drug delivery

Synergistic Catalysis by “Polymeric Microzymes and Inorganic Nanozymes”: The 1+1>2 Effect for Intramolecular Cyclization of Peptides

In this work, we developed an efficient “molecularly imprinted polymer microzymes and inorganic magnetic nanozymes” synergistic catalysis strategy for the formation of disulfide bonds in peptides. The polymeric microzymes showed excellent selectivity toward the template peptide as well as the main reactant (linear peptide), and the Fe3O4 magnetic nanoparticle (MNP) nanozymes inhibited the intermolecular reaction during the formation of disulfide bonds in peptides. As a result, the integration of the two different artificial enzymes in one process facilitates the intramolecular cyclization in high product yields (59.3%) with excellent selectivity. Mechanism study indicates the synergistic effect was occurred by using a “reversed solid phase synthesis” strategy with an enhanced shift of reaction balance to product generation. We believe the synergistic catalysis by “polymeric microzymes and inorganic nanozymes” presented in the present work may open new opportunities in creation of multifunctional enzyme mimics for sensing, imaging, and drug delivery

Molecularly imprinted magnetic materials prepared from modular and clickable nanoparticles

We report a new strategy toward construction of functional composite materials for fast molecular separation. Molecularly imprinted nanoparticles containing surface-exposed alkyne groups were synthesized by one-pot precipitation polymerization. Magnetic Fe3O4 nanoparticles were first coated with a silica shell, and then modified with terminal azide groups. The two types of clickable nanoparticles were conjugated through a Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction to give composite magnetic particles, which displayed high molecular recognition selectivity and could be easily separated using a simple magnet

Molecularly Imprinted Polymers for Clean Water: Analysis and Purification

Because of their predetermined selectivity, molecularly imprinted polymers (MIPs) have been extensively investigated to offer efficient separation of organic pollutants for water analysis and purification. In this review, we first describe the current development of water compatible MIPs, and the physical encapsulation and chemical immobilization of MIP particles for practical applications related to water analysis and purification. We summarize the challenges in understanding the mechanisms in molecular imprinting, with a special emphasis on the use of nuclear magnetic resonance (NMR), dynamic light scattering (DLS), and synchronous fluorescence spectroscopy to gain theoretical insights into the molecular imprinting process. The highlighted synthetic methods and the mechanistic investigations discussed in this review should facilitate the identification of the most crucial factors affecting the applications of MIPs for clean water

Molecularly imprinted photocatalyst with a structural analogue of template and its application.

To realize selective mineralization of low-level chlorophenols (CPs) in the presence of high-level ordinary pollutants, molecularly imprinted polymers (MIPs) coated photocatalyst was prepared using substrate analog as template. The pseudo-template imprinted photocatalysts showed rapid decomposition ability toward a group of CPs. Based on the complete dechlorination and spectrophotometry, a new method was proposed to detect the total organochlorine on CPs in water samples. The method showed good linearity when the concentrations of the total organochlorine on CPs is in the range of 12.0-200.0μmolL(-1). The detection limit is 1μmolL(-1) for this method. When this method was applied to measure the total organochlorine of the CPs in both tap water and river water samples, an average recovery ranged from 96.3% to 105.1% was obtained with RSD values less than 5%. In this green and simple method, the common inorganic ions in water showed no interference for the detection. The determination of the total organochlorine on the CPs might be used for estimation of the toxicity and the persistence of the water samples

Imprinted polymer beads enabling direct and selective molecular separation in water

In this paper, we describe the synthesis of water-compatible Molecularly Imprinted Polymer (MIP) microspheres by nanoparticle-stabilized emulsion (Pickering emulsion) polymerization. During the polymerization, the amount of the porogen used not only affected the stability of the Pickering emulsion but also the specific molecular recognition of the obtained MIP microspheres. Under optimized conditions, the MIP microspheres synthesized had a porous and hydrophilic surface. Scanning electron microscopy and fluorescent labeling experiments indicated that the MIP microspheres had particle sizes of 165 +/- 38 mu m. Selective molecular recognition with the MIP microspheres was studied through equilibrium binding analysis and liquid chromatography experiments under pure aqueous conditions. Using the new MIP microspheres as solid phase extraction (SPE) absorbents, low concentration organic pollutants (beta-blockers) were effectively enriched from tap water and easily detected using HPLC-MS analysis