Water-compatible imprinted polymers based on CS@SiO2particles for selective recognition of naringin

Properties, evaluation and application of naringin magnetic molecularly imprinted polymer based on synergistic imprinting strategy

A novel and facile surface molecularly imprinted polymer coated on magnetic chitosan (Fe3O4@CS@MIP) was fabricated for the selective recognition and enrichment of naringin (NRG). The Fe3O4@CS@MIP was prepared based on covalent-noncovalent synergistic imprinting strategies, utilizing 4-vinyl phenyl boric acid as covalent functional monomer, deep eutectic solvent (choline chloride/methacrylic acid [ChCl/MAA]) as non-covalent functional monomer and Fe3O4@CS nanoparticles as the magnetic support. The obtained Fe3O4@CS@MIP exhibited a uniform morphology, excellent crystallinity, outstanding magnetic properties, and high surface area. Owing to the double recognition abilities, the resultant polymer showed exceptional binding performance and rapid mass transfer in phosphate buffer (pH 7.0). The maximum binding amount of Fe3O4@CS@MIP was found to be 15.08 mg g-1, and the equilibrium adsorption could be achieved within 180 min. Moreover, they also exhibited stronger selectivity for NRG and satisfactory reusability, with only 11.0% loss after five adsorption-desorption cycles. Additionally, the Fe3O4@CS@MIP, serving as an adsorbent, presented practical application potential in the separation and enrichment of NRG from pummelo peel, with extraction efficiency in the range of 79.53% to 84.63%. This work provided a new strategy for improving the performance of MIP and contributed an attractive option for the extraction of NRG in complex samples.

Fabrication of double imprinted anchor points in cellulose nanocrystals-based hierarchical porous polyHIPEs for selective separation of flavoniods under physiological pH

Previous research had proved that molecular imprinted polymers can be used as separation material for removing Naringin (NRG) from agricultural pomelo wastes effectively. But the adsorption amounts of NRG molecules from traditional MIPs was quite low by using boronic acid as functional monomer because of single affinity interaction. Therefore, we developed the new combination of bifunctional monomers (i.e. low pKa boronate affinity monomer 2,4-difluoro-3-formylphenylboronic acid and dopamine) based on cellulose nanocrystals (CNCs) mixed with polymerized high internal phase emulsion (polyHIPE, PH) through an double layer surface imprinted method. The introduction of polyethylenimine (PEI) can offer abundant anchor units for the growth of more anchor sites to immobilization template molecules. Importantly, largely improved selective adsorption amounts (50.79 μmol g-1), which may be attribute to the fabrication of the uniform growth of double imprinted layers onto the polydopamine (PDA)/boronic acid-based surfaces. In addition, the resulting double recognition molecular imprinted polymers (MIPs) based on hypercrosslinked PH (DR-HCLPH@MIPs) not only exhibited fast adsorption kinetic of NRG molecule, but also possessed excellent selectivity and high adsorption capacities at physiological pH. Meanwhile, the coarse NRG from pomelo waste can be high selectively extracted to 94.74%. Overall, this study provides a versatile approach for fabrication of the sandwich-biscuit-like double imprinting layer porous MIPs for precise identification and ultrafast transport separation of NRG from complex samples.

Oriented, molecularly imprinted cavities with dual binding sites for highly sensitive and selective recognition of cortisol

Novel, molecularly imprinted polymers (MIPs) were developed for the highly sensitive and selective recognition of the stress marker cortisol. Oriented, homogeneous cavities with two binding sites for cortisol were fabricated by surface-initiated atom transfer radical polymerization, using a cortisol motif template molecule (TM1) which consists of a polymerizable moiety attached at the 3-carbonyl group of cortisol via an oxime linkage and an adamantane carboxylate moiety coupled with the 21-hydroxyl group. TM1 was orientationally immobilized on a β-cyclodextrin (β-CD)-grafted gold-coated sensor chip by inclusion of the adamantane moiety of TM1, followed by copolymerization of a hydrophilic comonomer, 2-methacryloyloxyethyl phosphorylcholine, with or without a cross-linker, N,N'-methylenebisacrylamide. Subsequent cleavage of the oxime linkage leaves the imprinted cavities that contain dual binding sites-namely, the aminooxy group and β-CD-capable of oxime formation and hydrophobic interaction, respectively. As an application, MIP-based picomolar level detection of cortisol was demonstrated by a competitive binding assay using a fluorescent competitor. Cross-linking of the MIP imparts rigidity to the binding cavities, and improves the selectivity and sensitivity significantly, reducing the limit of detection to 4.8 pM. In addition, detection of cortisol in saliva samples was demonstrated as a feasibility study.