Preparation of thermal-responsive magnetic molecularly imprinted polymers for selective removal of antibiotics from aqueous solution

Development of hydrophilic magnetic molecularly imprinted polymers by directly coating onto Fe3O4 with a water-miscible functional monomer and application in a solid-phase extraction procedure for iridoid glycosides

Development of hydrophilic magnetic molecularly imprinted polymers by directly coating onto Fe₃O₄ with a water-miscible functional monomer and application in a solid-phase extraction procedure for iridoid glycosides.

Temperature and magnetism bi-responsive molecularly imprinted polymers: Preparation, adsorption mechanism and properties as drug delivery system for sustained release of 5-fluorouracil

Temperature and magnetism bi-responsive molecularly imprinted polymers (TMMIPs) based on Fe3O4-encapsulating carbon nanospheres were prepared by free radical polymerization, and applied to selective adsorption and controlled release of 5-fluorouracil (5-FU) from an aqueous solution. Characterization results show that the as-synthesized TMMIPs have an average diameter of about 150 nm with a typical core-shell structure, and the thickness of the coating layer is approximately 50 nm. TMMIPs also displayed obvious magnetic properties and thermo-sensitivity. The adsorption results show that the prepared TMMIPs exhibit good adsorption capacity (up to 96.53 mg/g at 25 °C) and recognition towards 5-FU. The studies on 5-FU loading and release in vitro suggest that the release rate increases with increasing temperature. Meanwhile, adsorption mechanisms were explored by using a computational analysis to simulate the imprinted site towards 5-FU. The interaction energy between the imprinted site and 5-FU is -112.24 kJ/mol, originating from a hydrogen bond, Van der Waals forces and a hydrophobic interaction between functional groups located on 5-FU and a NIPAM monomer. The electrostatic potential charges and population analysis results suggest that the imprinted site of 5-FU can be introduced on the surface of TMMIPs, confirming their selective adsorption behavior for 5-FU.

A pH- and Temperature-Responsive Magnetic Composite Adsorbent for Targeted Removal of Nonylphenol

A pH- and temperature-responsive magnetic adsorbent [poly(N-isopropylacrylamide) grafted chitosan/Fe3O4 composite particles, CN-MCP], was synthesized for the removal of the endocrine-disrupting chemical nonylphenol. According to the structural characteristics (changeable surface-charge and hydrophilic/hydrophobic properties) of the targeted contaminant, CN-MCP was designed owning special structure (pH- and temperature-responsiveness for the changeable surface-charge and adjustable hydrophilic/hydrophobic properties, respectively). Compared to chitosan magnetic composite particles without grafting modification (CS-MCP) and several other reported adsorbents, CN-MCP exhibited relatively high adsorption capacity for nonylphenol under corresponding optimal conditions (123 mg/g at pH 9 and 20 °C; 116 mg/g at pH 5 and 40 °C). Meanwhile, high selectivity of the novel adsorbent in selective adsorption of nonylphenol from bisolute solution of nonylphenol and phenol was found. Effects of grafting ratio of the grafted polymer branches and coexisting inorganic salts on the adsorption were systematically investigated. Moreover, CN-MCP demonstrated desired reusability during 20 times of adsorption-desorption recycling. The high adsorption capacity, high selectivity, and desired reusability aforementioned revealed the significant application potential of CN-MCP in the removal of NP. On the basis of the adsorption behaviors, isotherms equilibrium, thermodynamics and kinetics studies, and instrumental analyses including X-ray photoelectron spectroscopy, BET specific surface area, zeta potential, and static water contact angle measurements, distinct adsorption mechanisms were found under various conditions: charge attraction between CN-MCP and the contaminant, as well as binding between polymeric branches of CN-MCP and nonyls, contributed to the adsorption at pH 9 and 20 °C; whereas hydrophobic interaction between CN-MCP and nonylphenol played a dominant role at pH 5 and 40 °C. The current study provided a strategy for the structural design of adsorbents according to the features of targeted emerging contaminants, and the continuity of the work was discussed and proposed.

Synthesis, characterization and application of core–shell magnetic molecularly imprinted polymers for selective recognition of clozapine from human serum

In this article, a magnetic molecularly imprinted polymer (MMIPs) based on Fe₃O₄@SiO₂ has been synthesized for simply extraction of clozapine (CLZ) from human serum.

Monodisperse magnetic ion imprinted polymeric microparticles prepared by RAFT polymerization based on γ-Fe2O3@meso-SiO2nanospheres for selective solid-phase extraction of Cu(ii) in water samples

Utilising a general protocol for making surface-imprinted core–shell microparticlesviaa RAFT-mediated approach, we developed a Cu(ii) imprinted polymer with a novel magnetic nanosphere, γ-Fe₂O₃@meso-SiO₂, as support.

Synthesis and characterization of core-shell magnetic molecularly imprinted polymers for solid-phase extraction and determination of Rhodamine B in food

Core-shell magnetic molecularly imprinted polymers (MIPs) nanoparticles (NPs), in which a Rhodamine B-imprinted layer was coated on Fe3O4 NPs. were synthesized. First, Fe3O4 NPs were prepared by a coprecipitation method. Then, amino-modified Fe3O4 NPs (Fe3O4@SiO2-NH2) was prepared. Finally, the MIPs were coated on the Fe3O4@SiO2-NH2 surface by the copolymerization with functional monomer, acrylamide, using a cross-linking agent, ethylene glycol dimethacrylate; an initiator, azobisisobutyronitrile and a template molecule, Rhodamine B. The Fe3O4@MIPs were characterized using a scanning electron microscope, Fourier transform infrared spectrometer, vibrating sample magnetometer, and re-binding experiments. The Fe3O4@MIPs showed a fast adsorption equilibrium, a highly improved imprinting capacity, and significant selectivity; they could be used as a solid-phase extraction material and detect illegal addition Rhodamine B in food. A method was developed for the selective isolation and enrichment of Rhodamine B in food samples with recoveries in the range 78.47-101.6% and the relative standard deviation was <2%.

Combination of surface imprinting and immobilized template techniques for preparation of core-shell molecularly imprinted polymers based on directly amino-modified Fe3O4 nanoparticles for specific recognition of bovine hemoglobin

In this work, the core-shell bovine hemoglobin (BHb)-imprinted superparamagnetic nanoparticles (Fe₃O₄@BHb-MIPs) were synthesized by combining for the first time a surface imprinting technique and a two-step immobilized template strategy. Initially, amino-functionalized Fe₃O₄ nanoparticles (Fe₃O₄@NH₂) were synthesized directly through a facile one-pot hydrothermal method. Next, BHb was immobilized on the surface of Fe₃O₄@NH₂ through non-covalent interactions. Then, siloxane co-polymerization on the Fe₃O₄@NH₂-protein complex surface resulted in a polymeric network molded around BHb which then became further immobilized. Finally, a thin polymer layer with specific recognition cavities for BHb was formed on the surface of Fe₃O₄@NH₂ after the removal of the template protein. The morphology and structure property of the prepared magnetic nanoparticles were characterized by transmission electronic microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometer (XRD), and vibrating sample magnetometer (VSM). To obtain the best selectivity and binding performance, the polymerization and adsorption conditions were investigated in detail. Under the optimized conditions, the Fe₃O₄@BHb-MIPs exhibited fast adsorption kinetics, large binding capacity, significant selectivity, and favorable reproducibility. The resultant Fe₃O₄@BHb-MIPs could not only specifically extract BHb from a mixed standard protein mixture, but also selectively enriched BHb from a real bovine blood sample. In addition, the synthetic process was quite simple and the stability and regeneration of the Fe₃O₄@BHb-MIPs were also satisfactory.

Smart drug delivery systems: from fundamentals to the clinic

Smart materials can endow implantable depots, targetable nanocarriers and insertable medical devices with activation-modulated and feedback-regulated control of drug release.