Development of a novel assay of molecularly imprinted membrane by design-based gaussian pattern for vancomycin determination

Fabrication of a surface molecularly imprinted polymer membrane based on a single template and its application in the separation and extraction of phenytoin, phenobarbital and lamotrigine

An innovative molecularly imprinted polymer membrane (MIPM) was prepared with polyvinylidene difluoride (PVDF) as the support, phenytoin (PHT) as the single template, methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the cross-linking reagent, azobisisobutyronitrile as the initiator, and acetonitrile-dimethylformamide (1 : 1.5, v/v) as the porogen. These materials were characterized via scanning electron microscopy, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller measurements and X-ray photoelectron spectroscopy. Their adsorption performances were evaluated through a series of experiments including isothermal adsorption, kinetic adsorption, selective adsorption, adsorption-desorption, reusability, and preparation reproducibility. Additionally, the application was explored by investigating the extraction recovery of MIPMs towards PHT, phenobarbital (PHB) and lamotrigine (LTG) in different matrices including methanol, normal saline (NS), phosphate buffer solution (PBS) and plasma. The results showed that MIPMs with rough and porous surfaces were successfully constructed, which offered good preparation reproducibility, reusability and selectivity. The adsorption capacities of MIPMs towards PHT, PHB and LTG were 2.312, 2.485 and 2.303 mg g-1, respectively, while their corresponding imprinting factors were 8.538, 12.122 and 4.562, respectively. The adsorption equilibrium of MIPMs was achieved within 20 min at room temperature without stirring or ultrasonication. The extraction recoveries of MIPMs for PHT, PHB or LTG in methanol, NS and PBS were more than 80% with an RSD% value of less than 3.64. In the case of plasma, the extraction recovery of MIPMs for PHT and PHB was more than 80% with an RSD% value of less than 2.41, while that of MIPMs for LTG was more than 65% with an RSD% value of less than 0.99. All the results indicated that the preparation method for MIPMs was simple, stable, and reliable, and the prepared MIPMs possessed excellent properties to meet the extraction application of PHT, PHB and LTG in different matrices.

Computer-Aided Prediction, Synthesis, and Characterization of Magnetic Molecularly Imprinted Polymers for the Extraction and Determination of Tolfenpyrad in Lettuce

Tolfenpyrad, a pyrazolamide insecticide, can be effectively used against pests resistant to carbamate and organophosphate insecticides. In this study, a molecular imprinted polymer using tolfenpyrad as a template molecule was synthesized. The type of functional monomer and the ratio of functional monomer to template were predicted by density function theory. Magnetic molecularly imprinted polymers (MMIPs) were synthesized using 2-vinylpyridine as a functional monomer in the presence of ethylene magnetite nanoparticles at a monomer/tolfenpyrad ratio of 7:1. The successful synthesis of MMIPs is confirmed by the results of the characterization analysis by scanning electron microscopy, nitrogen adsorption-desorption isotherms, Fourier transform infrared spectroscopy, X-ray diffractometer, thermogravimetric analyzer, and vibrational sample magnetometers. A pseudo-second-order kinetic model fit the adsorption of tolfenpyrad, and the kinetic data are in good agreement with the Freundlich isothermal model. The adsorption capacity of the polymer to the target analyte was 7.20 mg/g, indicating an excellent selective extraction capability. In addition, the adsorption capacity of the MMIPs is not significantly lost after several reuses. The MMIPs showed great analytical performance in tolfenpyrad-spiked lettuce samples, with acceptable accuracy (intra- and inter-day recoveries of 90.5-98.8%) and precision (intra- and inter-day relative standard deviations of 1.4-5.2%).

The Use of Computational Methods for the Development of Molecularly Imprinted Polymers

Recent years have witnessed a dramatic increase in the use of theoretical and computational approaches in the study and development of molecular imprinting systems. These tools are being used to either improve understanding of the mechanisms underlying the function of molecular imprinting systems or for the design of new systems. Here, we present an overview of the literature describing the application of theoretical and computational techniques to the different stages of the molecular imprinting process (pre-polymerization mixture, polymerization process and ligand-molecularly imprinted polymer rebinding), along with an analysis of trends within and the current status of this aspect of the molecular imprinting field.

A Review on Molecularly Imprinted Polymers Preparation by Computational Simulation-Aided Methods

Molecularly imprinted polymers (MIPs) are obtained by initiating the polymerization of functional monomers surrounding a template molecule in the presence of crosslinkers and porogens. The best adsorption performance can be achieved by optimizing the polymerization conditions, but this process is time consuming and labor-intensive. Theoretical calculation based on calculation simulations and intermolecular forces is an effective method to solve this problem because it is convenient, versatile, environmentally friendly, and inexpensive. In this article, computational simulation modeling methods are introduced, and the theoretical optimization methods of various molecular simulation calculation software for preparing molecularly imprinted polymers are proposed. The progress in research on and application of molecularly imprinted polymers prepared by computational simulations and computational software in the past two decades are reviewed. Computer molecular simulation methods, including molecular mechanics, molecular dynamics and quantum mechanics, are universally applicable for the MIP-based materials. Furthermore, the new role of computational simulation in the future development of molecular imprinting technology is explored.

Recent Advances in Molecularly Imprinted Membranes for Sample Treatment and Separation

This review describes the recent advances from the past five years concerning the development and applications of molecularly imprinted membranes (MIMs) in the field of sample treatment and separation processes. After a short introduction, where the importance of these materials is highlighted, a description of key aspects of membrane separation followed by the strategies of preparation of these materials is described. The review continues with several analytical applications of these MIMs for sample preparation as well as for separation purposes covering pharmaceutical, food, and environmental areas. Finally, a discussion focused on possible future directions of these materials in extraction and separation field is also given.

Design and Preparation of Molecularly Imprinted Membranes for Selective Separation of Acteoside

Acteoside (ACT) belongs to a type of phenylethanoid glycosides (PhGs), and it is worthy of obtaining high-purity due to its significant medicinal functions. In this study, a novel class of MIMs was designed and synthesized with PVDF membranes as the base membrane for high selective separation and enrichment of ACT. The effects of the different functional monomers, the amounts of functional monomers, crosslinking agents, and initiators on the separation properties of MIMs were investigated. Furthermore, adsorption ability, permeation capacity, and reusability of MIMs were discussed for ACT. It indicated that MIM7 was the optimal performance of MIMs. The adsorption ability of MIM7 for ACT was 62.83 mg/g, and the selectivity factor (α) of MIM7 was up to 2.74 and its permeability factor (β) was greater than 2.66. Moreover, the adsorption amount of MIM7 was still more than 88.57% of the initial value after five cycles. As an ACT imprinted layer of MIMs only had recognition sites for ACT molecules, which recombined with the recognition sites in the membrane permeation experiment, ACT molecules penetration was hindered. However, the analogs of ECH successfully passed MIMs. It indicated that the selective MIMs for ACT followed the mechanism of delayed permeation. This work provides an important reference for the high permselective separation of natural products.

Antifouling molecularly imprinted membranes for pretreatment of milk samples: Selective separation and detection of lincomycin

As a veterinary antibiotic, lincomycin (LIN) residues in milk are raising concerns of public on account of potential harm to human health. Efficient strategy is eagerly desired for detection of LIN from milk samples. Hence, lincomycin molecularly imprinted membranes (LINMIMs) were developed for selective separation of LIN as an efficient pretreatment of milk samples. The synergistic effect of polyethylenimine and dopamine provided effective antifouling performance by improving the hydrophilicity. Based on click chemistry, specific recognition sites were facilely formed on membranes using 4-vinylpyridine as functional monomers. The satisfactory rebinding capacity (151.62 mg g^-1), permselectivity (4.43), together with the linear dependence (R² = 0.9902) of concentrations in eluents and original samples. Moreover, the method was utilized to determine LIN from milk, with good recovery and relative standard deviation. Achievements in this work will actively promote the development of efficient detection technology.