A deep eutectic solvent magnetic molecularly imprinted polymer for extraction of laminarin from seaweeds

Magnetic molecular imprinted polymers (MIPs) based on 4-vinylbenzyltrimethylammonium chloride (VBTAC) and 4-vinylbenzoic acid (VBA) deep eutectic solvent as dual functional monomers was successfully synthesized for the specific recognition of laminarin. The MIPs were characterized by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, thermal gravimetric analysis, and vibrating sample magnetometer analysis. The results showed that the MIPs were spheres of a uniform size, with the surface rich in cavities and excellent superparamagnetism properties. The adsorption experiments showed that MIPs conform to pseudo-second-order kinetics and Langmuir isotherm adsorption. The maximum adsorption capacity under optimal conditions was 322.58 μg·mg^-1 and the imprinting factor was 2.13. Under the optimized conditions, the limit of detection (LOD) of the developed material was 6.6 µM. Linearity of the material was obtained within the range 20-800 µM with a coefficient of determination (r²) being better 0.999. Relative standard deviations (RSDs) were less than 3.96%, and satisfactory recoveries were between 94.55 and 97.39%. The actual sample analysis manifested that MIPs could effectively separate laminarin from Laminarin japonica Aiesch.

Starch engineered with Moringa oleifera seeds protein crosslinked Fe3O4: A synthesis and flocculation studies

This study aimed to utilize cationic protein extracted from the Moringa oleifera seed in the fabrication of cationic starch crosslinked with magnetic nanoparticles (MagCS). Important synthesis parameters include starch to cationic protein volume ratio, magnetic nanoparticles mass fraction, reaction and crosslinking time, reaction and crosslinking temperature and crosslinker concentration. At optimum synthesis conditions, MagCS yield a 38.55% amide content, 2.46 degree of substitution, 1.1 mmol/g charge density and 78.6% crosslinking, which are much higher compared to other starch derivatives. A series of characterization analyses such as Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, elemental analysis and vibrating sample magnetometer concluded that MagCS was embedded with amide group, has high crystallinity structure, is thermally stable and shows a promising magnetic characteristic. Based on the synthesis parameters and characterization studies, the synthesis mechanism of MagCS was also postulated. The flocculation performance of MagCS was successfully assessed for the treatment of palm oil mill effluent. At optimum dosage, initial pH and settling time of 1.0 g/L, 9.0 and 15 min, the MagCS flocculant was able to remove 90.48, 83.95 and 58.19% of turbidity, color and chemical oxygen demand, respectively. This study provides an alternative eco-friendly materials in the wastewater treatment application.

Separation and enrichment of sibiskoside from Sibiraea angustat with magnetic surface dummy template molecularly imprinted polymers

In this work, a novel strategy was developed for separation and enrichment of sibiskoside by dummy molecular imprinting technology and magnetic separation technology. The structural analogue geniposide was selected as the dummy template, using 4-vinylpyridine as the functional monomer, ethylene glycol dimethacrylate as the cross-linking agent, and acetonitrile as the porogen. The molecularly imprinted layer was formed on the surface of the magnetic carrier to prepare dummy template molecularly imprinted polymers (DMIPs) with a core-shell structure. The DMIPs were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and Vibration sample magnetometer (VSM). The results of adsorption kinetics experiments and isothermal adsorption experiments showed that DMIPs can reach adsorption equilibrium in a short period of time and the maximum adsorption capacity can reach 14.67 mg/g. The imprinting factor was 2.08. Compared with the andrographolide, polydatin, arbutin, caffeic acid, neohesperidin dihydrochalcone and quercetin, DMIPs have good adsorption capacity for the sibiskoside. And the reusability was better. After the adsorption of DMIPs, the purity of sibiskoside in the crude extracts from Sibiraea angustata increased to 78%. It provided a basis for the further development and utilization of Sibiraea angustata as well as the separation and enrichment of monoterpenes.

Construction of a selective non-enzymatic electrochemical sensor based on hollow nickel nanospheres/carbon dots–chitosan and molecularly imprinted polymer film for the detection of glucose

A non-enzymatic glucose electrochemical sensor platform was fabricated by assembling hollow nickel nanospheres/carbon dots–chitosan and molecularly imprinted polymer film modified a glass carbon electrode.

Molecularly Imprinted Materials for Selective Biological Recognition

Molecular imprinting is an approach of generating imprinting cavities in polymer structures that are compatible with the target molecules. The cavities have memory for shape and chemical recognition, similar to the recognition mechanism of antigen-antibody in organisms. Their structures are also called biomimetic receptors or synthetic receptors. Owing to the excellent selectivity and unique structural predictability of molecularly imprinted materials (MIMs), practical MIMs have become a rapidly evolving research area providing key factors for understanding separation, recognition, and regenerative properties toward biological small molecules to biomacromolecules, even cell and microorganism. In this review, the characteristics, morphologies, and applicability of currently popular carrier materials for molecular imprinting, especially the fundamental role of hydrogels, porous materials, hierarchical nanoparticles, and 2D materials in the separation and recognition of biological templates are discussed. Moreover, through a series of case studies, emphasis is given on introducing imprinting strategies for biological templates with different molecular scales. In particular, the differences and connections between small molecular imprinting (bulk imprinting, "dummy" template imprinting, etc.), large molecular imprinting (surface imprinting, interfacial imprinting, etc.), and cell imprinting strategies are demonstrated in detail. Finally, future research directions are provided.

Amido surface-functionalized magnetic molecularly imprinted polymers for the efficient extraction of Sibiskoside from Sibiraea angustata

A general method for efficient and selective extraction of a target compound from complex natural products remains elusive, despite decades of research. By introducing a functional amido group on the surface of dispersity-enhanced magnetic nanoparticles, a nanoparticle receptor to selectively recognize Sibiskoside (a monoterpene) from the aerial portion of Sibiraea angustata by hydrogen bond interaction was synthesized. The superparamagnetic Fe₃O₄ nanoparticles were successively modified with tetraethyl orthosilicate (TEOS), amino and amido functional groups, and 4-vinylbenzoic acid (VBZA) was used as the functional monomer. A thin layer of poly (VBZA) imprinted with Sibiskoside was immobilized on the surface of magnetic carriers. Attributing to the amido group introduced into the magnetic particles, the template could attract and bind to the surface and promote the formation of a hydrogen bond system between the carrier, template molecules and functional monomer. High-density molecular recognition sites grew on the surface of magnetic substrate. The adsorption reached equilibrium at approximately 150 min, while fast adsorption occurred during the first 60 min. The maximum adsorption capacity has been found to be 13.75 mg g^-1 according to calculation with the Langmuir isotherm. The selectivity coefficients of Molecular imprinting polypers (MIPs) for Sibiskoside with respect to Andrographolide, Loganin, Gastrodin, geraniol-1-O-[α-l-rhamnopyranosyl-(1 → 6)-1-β-d-glucopyranoside] (GRG), Sibiscolacton and Sibiraic acid were 2.26, 1.43, 1.701.56, 1.05, 0.73 and, respectively. The results indicated that the MIPs possessed good specific adsorption capacity and selectivity toward Sibiskoside and had the potential to be a candidate for the separation and purification of monoterpenes from Sibiraea angustata, which is of great significance to obesity management.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2013-2014

This review is the eighth update of the original article published in 1999 on the application of Matrix-assisted laser desorption/ionization mass spectrometry (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2014. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, and arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly- saccharides, glycoproteins, glycolipids, glycosides, and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions, and applications to chemical synthesis. © 2018 Wiley Periodicals, Inc. Mass Spec Rev 37:353-491, 2018.

Fabrication of magnetic Fe3O4@nSiO2@mSiO2-NH2 core-shell mesoporous nanocomposite and its application for highly efficient ultrasound assisted dispersive µSPE-spectrofluorimetric detection of ofloxacin in urine and plasma samples

In this research, a sensitive, simple and rapid ultrasound assisted dispersive micro solid-phase extraction (USAD-µSPE) was developed using a synthesized core-shell magnetic mesoporous nanocomposite (Fe₃O₄@nSiO₂@mSiO₂-NH₂) as an efficient adsorbent for the preconcentration and spectrofluorometric determination of ofloxacin (OFL) in biological samples. The synthesized adsorbent was characterized using FT-IR spectroscopy, transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), energy dispersive X-ray (EDX) spectroscopy, thermogravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET) analysis. The application of this magnetic nanocomposite as a sensitive solid phase for removal, preconcentration and spectrofluorometric quantification of trace amount of OFL was developed. Influence of various variables including pH, sorbent dosage, desorption solvent properties and sonication time on present method response was studied and optimized. The results showed that using the proposed method OFL can be determined in the linear concentration range of 1.0-500.0µgL^-1 with a limit of detection as low as 0.21µgL^-1 and relative standard deviation less than 2.5 (%). The results of human urine and blood plasma analysis showed that the method is a good candidate for biological sample analysis purposes.

Preparation and characterization of surface molecularly imprinted film coated on a magnetic nanocore for the fast and selective recognition of the new neonicotinoid insecticide paichongding (IPP)

The selective recognition of IPP-MMIPs and IPP-MNIPs for four kinds of neonicotinoid insecticides, including IPP, imidacloprid, thiamethoxam and thiacloprid.

Molecularly imprinted polymers for separating and sensing of macromolecular compounds and microorganisms

The present review article focuses on gathering, summarizing, and critically evaluating the results of the last decade on separating and sensing macromolecular compounds and microorganisms with the use of molecularly imprinted polymer (MIP) synthetic receptors. Macromolecules play an important role in biology and are termed that way to contrast them from micromolecules. The former are large and complex molecules with relatively high molecular weights. The article mainly considers chemical sensing of deoxyribonucleic acids (DNAs), proteins and protein fragments as well as sugars and oligosaccharides. Moreover, it briefly discusses fabrication of chemosensors for determination of bacteria and viruses that can ultimately be considered as extremely large macromolecules.

Specific removal of protein using protein imprinted polydopamine shells on modified amino-functionalized magnetic nanoparticles

A simple approach for the specific removal of protein using polydopamine imprinted shells on modified amino-functionalized magnetic nanoparticles was developed.