Molecularly Imprinted Polymers for Dispersive (Micro)Solid Phase Extraction: A Review

The review describes the development of batch solid phase extraction procedures based on dispersive (micro)solid phase extraction with molecularly imprinted polymers (MIPs) and magnetic MIPs (MMIPs). Advantages and disadvantages of the various MIPs for dispersive solid phase extraction and dispersive (micro)solid phase extraction are discussed. In addition, an effort has also been made to condense the information regarding MMIPs since there are a great variety of supports (magnetite and magnetite composites with carbon nanotubes, graphene oxide, or organic metal framework) and magnetite surface functionalization mechanisms for enhancing MIP synthesis, including reversible addition-fragmentation chain-transfer (RAFT) polymerization. Finally, drawbacks and future prospects for improving molecularly imprinted (micro)solid phase extraction (MIMSPE) are also appraised.

Protein Denaturation Through the Use of Magnetic Molecularly Imprinted Polymer Nanoparticles

The inhibition of the protein function for therapeutic applications remains challenging despite progress these past years. While the targeting application of molecularly imprinted polymer are in their infancy, no use was ever made of their magnetic hyperthermia properties to damage proteins when they are coupled to magnetic nanoparticles. Therefore, we have developed a facile and effective method to synthesize magnetic molecularly imprinted polymer nanoparticles using the green fluorescent protein (GFP) as the template, a bulk imprinting of proteins combined with a grafting approach onto maghemite nanoparticles. The hybrid material exhibits very high adsorption capacities and very strong affinity constants towards GFP. We show that the heat generated locally upon alternative magnetic field is responsible of the decrease of fluorescence intensity.

Molecularly Imprinted Polymer and Computational Study of (E)-4-(2- cyano-3-(dimethylamino)acryloyl)benzoic Acid from Poly(ethylene terephthalate) Plastic Waste

Background:

Molecularly imprinted polymers (MIPs) are utilized in the separation of a pure compound from complex matrices. A stable template-monomer complex generates MIPs with the highest affinity and selectivity for the template. In this investigation, degradation of Poly(ethylene terephthalate) PET afforded the (E)-4-(2-cyano-3-(dimethylamino) acryloyl) benzoic acid (4) (TAM) which used TAM as template which interacts with Methacrylic Acid (MAA) monomer, in the presence of CH3CN as progen. The TAM-MMA complex interactions are dependent on stable hydrogen bonding interaction between the carboxylic acid group of TAM and the hydroxyl group of MMA with minimal interference of porogen CH3CN. The DFT/B3LYP/6-31+G model chemistry was used to optimize their structures and frequency calculations. The binding energies between TAM with different monomers showed the most stable molar ratio of 1:4 which was confirmed through experimental analysis.

Methods:

The present work describes the synthesis of (E)-4-(2-cyano-3-(dimethylamino) acryloyl) benzoic acid (4) (TAM) from PET waste and formation of molecularly imprinted polymer from TAM with the methacrylic acid monomer. The optimization of molecular imprinted was stimulated via DFT/B3LYP/6-31G (d). The imprinted polymer film was characterized via thermal analysis, pore size, FT-IR and scanning electron microscopy.

Results:

The most stable molecularly imprinted polymers (MIPs) showed binding energy of TAM(MMA4)=-2063.456 KJ/mol with a small value of mesopores (10-100 Å). Also, the sorption capability of TAM-MIPs showed 6.57 mg/g using STP-MIP-9VC. Moreover, the average pore size ranged between 0.2-1 nm with the BET surface about 300 m2/g.

Conclusion:

The proposed TAM exhibited a high degree of selectivity for MMA in comparison with other different monomers through hydrogen bond interaction, which was thermally stable, good reproducibility and excellent regeneration capacity and elucidated in the computational study and analytical analysis.

Preparation of magnetic molecularly imprinted polymers for the rapid detection of diethylstilbestrol in milk samples

BACKGROUND

Diethylstilbestrol (DES) residues are harmful to human health because of their potential carcinogenic properties. Therefore, it is important to develop a fast and efficient pretreatment method to prevent their harmful effects on human health and the environment.

RESULTS

In this paper, two types of magnetic molecularly imprinted polymers (MMIPs) of DES were prepared by bulk polymerization and the sol-gel method, respectively. The synthetic materials were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis. Adsorption capacities of the bulk and sol-gel MMIPs were investigated. A rapid detection method was developed using the two types of MMIPs as sorbents, coupled to high-performance liquid chromatography, for the determination of DES residues in milk samples. Under optimized conditions, the limit of detection (S/N = 3) of both methods for DES was 2.0 μg L^-1 ; and the linear response range to DES was 0.1-500 mg L^-1 . The milk samples were analyzed according to this method with good recoveries of 88.3-97.6 and 90.5-103.5% for the two types of MMIPs, respectively.

CONCLUSIONS

The method described had high sensitivity and high selectivity, and could prove to be a new method for the rapid determination of DES residues in milk samples. © 2019 Society of Chemical Industry.

Surface-initiated synthesis of bulk-imprinted magnetic polymers for protein recognition

Bulk imprinting of proteins was used combined with a grafting approach onto maghemite nanoparticles to develop a faster and simpler polymerization method for the synthesis of magnetic protein imprinted polymers with very high adsorption capacities and very strong affinity constants.

Magnetic protein imprinted polymers: a review

Protein imprinted polymers have received a lot of interest in the past few years because of their applications as tailor-made receptors for biomacromolecules. Generally, the preparation of these polymers requires numerous and time-consuming steps. But their coupling with magnetic nanoparticles simplifies and speeds up the synthesis of these materials. Some recent papers describe the use of protein imprinted polymer (PIP) coupled to magnetic iron oxide nanoparticles (MION) for the design of MION@PIP biosensors. With such systems, a target protein can be specifically and selectively captured from complex media due to exceptional chemical properties of the polymer. Despite such performances, only a limited number of studies address these hybrid nanosystems. This review focuses on the chemistry and preparation of MION@PIP nanocomposites as well as on the metrics used to characterize their performances.

One-pot synthesis of uniform and monodisperse superparamagnetic molecularly imprinted polymer nanospheres through a sol–gel process for selective recognition of bisphenol A in aqueous media

Uniform and monodisperse Fe₃O₄@MIP nanospheres were directly synthesized using a sol–gel method on the surface of Fe₃O₄–COOH spheres.

Boronic acid based imprinted electrochemical sensor for rutin recognition and detection

An electrochemical sensor based on boronic acid affinity and molecular imprinted polymer specific binding was developed for rutin dual-recognition and sensitive detection.

Design of magnetic molecularly imprinted polymer nanoparticles for controlled release of doxorubicin under an alternative magnetic field in athermal conditions

An innovative magnetic delivery nanomaterial for triggered cancer therapy showing active control over drug release by using an alternative magnetic field is proposed. In vitro and In vivo release of doxorubicin (DOX) were investigated and showed a massive DOX release under an alternative magnetic field without temperature elevation of the medium.

Selective extraction and determination of fluoroquinolones in bovine milk samples with montmorillonite magnetic molecularly imprinted polymers and capillary electrophoresis

A sensitive and selective method for separating fluoroquinolones (FQs) from bovine milk samples was successfully developed using montmorillonite magnetic molecularly imprinted polymers (MMMIPs) as adsorbents. MMMIPs were prepared using montmorillonite as carrier, fleroxacin (FLE) as template molecule, and Fe3O4 magnetite as magnetic component. MMMIPs possessed high adsorption capacity of 46.3 mg g(-1) for FLE. A rapid and convenient magnetic solid-phase extraction procedure coupled with capillary electrophoresis was established with MMMIPs as adsorbents for simultaneous and selective extraction of four FQs in bovine milk samples. Limits of detection ranged between 12.9 and 18.8 μg L(-1), and the RSDs were between 1.8% and 8.6%. The proposed method was successfully applied to spike bovine milk samples with recoveries of 92.7%-108.6%.

Functionalization of nanomaterials with aryldiazonium salts

This paper reviews the surface modification strategies of a wide range of nanomaterials using aryldiazonium salts. After a brief history of diazonium salts since their discovery by Peter Griess in 1858, we will tackle the surface chemistry using these compounds since the first trials in the 1950s. We will then focus on the modern surface chemistry of aryldiazonium salts for the modification of materials, particularly metallic, semiconductors, metal oxide nanoparticles, carbon-based nanostructures, diamond and clays. The successful modification of sp(2) carbon materials and metals by aryldiazonium salts paved the way to innovative strategies for the attachment of aryl layers to metal oxide nanoparticles and nanodiamonds, and intercalation of clays. Interestingly, diazotized surfaces can easily trap nanoparticles and nanotubes while diazotized nanoparticles can be (electro)chemically reduced on electrode/materials surfaces as molecular compounds. Both strategies provided organized 2D surface assembled nanoparticles. In this review, aryldiazonium salts are highlighted as efficient coupling agents for many types of molecular, macromolecular and nanoparticulate species, therefore ensuring stability to colloids on the one hand, and the construction of composite materials and hybrid systems with robust and durable interfaces/interphases, on the other hand. The last section is dedicated to a selection of patents and industrial products based on aryldiazonium-modified nanomaterials. After nearly 160 years of organic chemistry, diazonium salts have entered a new, long and thriving era for the benefit of materials, colloids, and surface scientists. This tempts us to introduce the terminology of "diazonics" we define as the science and technology of aryldiazonium salt-derived materials.

Enhanced Antifouling Properties of Carbohydrate Coated Poly(ether sulfone) Membranes

Poly(ether sulfone) membranes (PES) were modified with biologically active monosaccharides and disaccharides using aryldiazonium chemistry as a mild, one-step, surface-modification strategy. We previously proposed the modification of carbon, metals, and alloys with monosaccharides using the same method; herein, we demonstrate modification of PES membranes and the effect of chemisorbed carbohydrate layers on their resistance to biofouling. Glycosylated PES surfaces were characterized using spectroscopic methods and tested against their ability to interact with specific carbohydrate-binding proteins. Galactose-, mannose-, and lactose-modified PES surfaces were exposed to Bovine Serum Albumin (BSA) solutions to assess unspecific protein adsorption in the laboratory and were found to adsorb significantly lower amounts of BSA compared to bare membranes. The ability of molecular carbohydrate layers to impart antifouling properties was further tested in the field via long-term immersive tests at a wastewater treatment plant. A combination of ATP content assays, infrared spectroscopic characterization and He-ion microscopy (HIM) imaging were used to investigate biomass accumulation at membranes. We show that, beyond laboratory applications and in the case of complex aqueous environments that are rich in biomass such as wastewater effluent, we observe significantly lower biofouling at carbohydrate-modified PES than at bare PES membrane surfaces.

Surface modification of poly(D,L-lactic acid) scaffolds for orthopedic applications: a biocompatible, nondestructive route via diazonium chemistry

Scaffolds made with synthetic polymers such as polyesters are commonly used in bone tissue engineering. However, their hydrophobicity and the lack of specific functionalities make their surface not ideal for cell adhesion and growth. Surface modification of these materials is thus crucial to enhance the scaffold's integration in the body. Different surface modification techniques have been developed to improve scaffold biocompatibility. Here we show that diazonium chemistry can be used to modify the outer and inner surfaces of three-dimensional poly(D,L-lactic acid) (PDLLA) scaffolds with phosphonate groups, using a simple two-step method. By changing reaction time and impregnation procedure, we were able to tune the concentration of phosphonate groups present on the scaffolds, without degrading the PDLLA matrix. To test the effectiveness of this modification, we immersed the scaffolds in simulated body fluid, and characterized them with scanning electron microscopy, X-ray photoelectron spectroscopy, Raman, and infrared spectroscopy. Our results showed that a layer of hydroxyapatite particles was formed on all scaffolds after 2 and 4 weeks of immersion; however, the precipitation was faster and in larger amounts on the phosphonate-modified than on the bare PDLLA scaffolds. Both osteogenic MC3T3-E1 and chondrogenic ATDC5 cell lines showed increased cell viability/metabolic activity when grown on a phosphonated PDLLA surface in comparison to a control PDLLA surface. Also, more calcium-containing minerals were deposited by cultures grown on phosphonated PDLLA, thus showing the pro-mineralization properties of the proposed modification. This work introduces diazonium chemistry as a simple and biocompatible technique to modify scaffold surfaces, allowing to covalently and homogeneously bind a number of functional groups without degrading the scaffold's polymeric matrix.

Recyclable removal of bisphenol A from aqueous solution by reduced graphene oxide-magnetic nanoparticles: adsorption and desorption

Reduced graphene oxide (rGO) nanosheets decorated with tunable magnetic nanoparticles (MNPs) were synthesized by a simple co-precipitation method and employed for recyclable removal of bisphenol A (BPA) from aqueous solution. The morphological characterization shows that Fe3O4 nanoparticles are uniformly deposited on rGO sheets. The magnetic characterization demonstrates that composites with various amounts of Fe3O4 nanoparticles are superparamagnetic. Due to the superparamagnetism, rGO-MNPs were used as recyclable adsorbents for BPA removal in aqueous solution. The kinetics of the adsorption process and the adsorption isotherm were investigated. The results indicate that the adsorption process is fitted to Langmuir model and the composites with lower density of MNPs represent better adsorption ability. In addition, its kinetics follows pseudo-second-order rate equation. Moreover, the adsorbents could be recovered conveniently by magnetic separation and recyclable used because of the easy desorption of BPA.

Ultrasensitive detection of bisphenol A in aqueous media using photoresponsive surface molecular imprinting polymer microspheres

A photoresponsive SMIP was prepared for photocontrolled detection of trace bisphenol A in aqueous media with simplicity and good efficiency.

E-assay concept: detection of bisphenol A with a label-free electrochemical competitive immunoassay

A label-free electrochemical immunosensor was developed by electropolymerization of N-(3-(4-(2-(4-hydroxyphenyl)propan-2-yl)phenoxy)propyl) 3-(5-hydroxy-1,4-dihydro-1,4-dioxonaphthalen-2(3)-yl)propionamide (JugBPA). By combination with an antibody directed to bisphenol A (αBPA), this conducting polymer-based biosensor can detect BPA directly with a limit of detection of 2pgmL(-1). Square wave voltammetry shows that the polymer film presents a current decrease upon anti-BPA binding and an opposite current increase upon BPA addition in solution. This electrochemical immunosensor (E-assay) also shows high selectivity towards closely related compounds (bisphenol A dimethacrylate, and dibutyl phthalate). The E-assay concept described here could be a promising tool for simple, low-cost and reagentless on-site environmental monitoring.

Functionalization of magnetic nanocrystals by oligo (ethylene oxide) chains carrying diazonium and iniferter end groups

The water stability of iron oxide nanoparticles (NPs) is a major issue for biomedical and biological applications. This paper presents a versatile approach for preparing water-soluble iron oxide nanoparticles coated by bifunctional oligo(ethylene oxide) (OEO) chains, carrying on the one side a diazonium end group for covalent grafting at the NP surface and on the other side an iniferter group (diethyl dithiocarbamate) for initiating the growing of poly(methacrylic acid). The nanoparticles were synthesized by coprecipitation in basic media and functionalized in situ by adding the diazonium salt directly in the synthesis medium. Oligo(ethylene oxide) with various chain lengths (from one to three monomer units) was grafted at the NP surface using this approach. The length of the OEO spacer between the NP surface and the iniferter end group was found to be a critical parameter for controlling the colloidal stability of the hybrid NPs. The polymerization time was also shown to strongly influence their colloidal stability, emphasizing the interest to control the interfacial properties of the hybrids for obtaining stable dispersions in water.

Molecularly imprinted polymeric microspheres with metalloporphyrin-based molecular recognition sites coassembled with methacrylic acid

Molecularly imprinted polymeric microspheres (MIPMs) for dimethyl methylphosphonate (DMMP) were prepared using methacrylic acid (MAA) and vinyl-substituted zinc(ii) porphyrin as functional monomers. The interactions of vinyl-substituted zinc(ii) porphyrin with DMMP were determined by ultraviolet–visible absorption spectroscopy. A comparison between the MIPMs-MAA that used only MAA with the MIPMs-zinc (Zn) + MAA that used both MAA and Zn porphyrin as functional monomers revealed that the MIPMs-Zn + MAA showed higher binding ability for DMMP. By the Scatchard analysis, the results of the equilibrium adsorption test showed that the MIPM-DMMP only had one affinity binding site. The dissociation constants of MIPMs-Zn + MAA and MIPMs-MAA were 0.167 and 0.338 mmol/L, respectively, and the maximum absorption quantities were 148 and 13.57 μmol/g, respectively. The MIPMs-Zn + MAA possessed the higher selectivity for DMMP as shown by the isotherm binding test. These results revealed that the MIPMs-Zn + MAA had highly specific binding sites because they were assembled by the two functional monomers, vinyl-substituted Zn(ii) porphyrin and MAA, which coordinated to achieve specific binding with DMMP.

Preparation of magnetic molecularly imprinted polymers for bisphenol A and its analogues and their application to the assay of bisphenol A in river water

Magnetic molecularly imprinted polymers (M-MIPs) for bisphenol A (BPA) and its structural analogues have been prepared by a multi-step swelling and polymerization method using uniformly-sized magnetic particles as a shape template. Binding experiments and Scatchard analyses revealed that two classes of binding sites were formed on M-MIP(BPA). The retention and molecular-recognition properties of M-MIPs for BPA and its structural analogues were evaluated using a mixture of phosphate buffer and acetonitrile or a mixture of water and acetonitrile as a mobile phase by LC. M-MIPs for BPA and [²H₁₆]BPA (BPA-d₁₆), M-MIP(BPA) and M-MIP(BPA-d16), showed almost the same imprinting factors for BPA, while M-MIP for bisphenol B (2,2-bis(4-hydroxyphenyl)butane, BPB), M-MIP(BPB), gave the moderate imprinting factor for BPA. Furthermore, M-MIP(BPB) was applied for the selective extraction and determination of BPA in environmental water samples. The concentration of BPA in river water samples was determined to be 68 ng/L.