Specific capture and determination of glycoprotein using a hybrid epitopes and monomers-mediated molecular-imprinted polymer enzyme-free electrochemical biosensor.

A novel molecular-imprinted polymer (MIP)-based enzyme-free biosensor was created for the selective detection of glycoprotein transferrin (Trf). For this purpose, MIP-based biosensor for Trf was prepared by electrochemical co-polymerization of novel hybrid monomers 3-aminophenylboronic acid (M-APBA) and pyrrole on a glassy carbon electrode (GCE) modified with carboxylated multi-walled carbon nanotubes (cMWCNTs). Hybrid epitopes of Trf (C-terminal fragment and glycan) have been selected as templates. The produced sensor exhibited great selective recognition ability toward Trf under optimal preparation conditions, offering good analytical range (0.125-1.25 µM) with a detection limit of 0.024 µM. The proposed hybrid epitope in combination with hybrid monomer-mediated imprinting strategy was successfully applied to detect Trf in spiked human serum samples, with recoveries and relative standard deviations ranging from 94.7 to 106.0% and 2.64 to 5.32%, respectively. This study provided a reliable protocol for preparing hybrid epitopes and monomers-mediated MIP for the synergistic and effective determination of glycoprotein in complicated biological samples.

Using Quercetin to Construct Molecularly Imprinting Polymer in the Preparation and Enrichment of Flavonol and Flavonoid Compounds.

Flavonol and flavonoid compounds are important natural compounds with various biomedical activities. Therefore, it is of great significance to develop a strategy for the specific extraction of flavonol and flavonoid compounds. Quercetin is a well-studied flavonoid possessing many health benefits. This compound is a versatile antioxidant known to possess protective abilities against body tissue injury induced by pathological situations and various drug toxicities. Although quercetin is widely distributed in many plants, its content generally is not very high. Therefore, the specific extraction of quercetin as well as other flavonol and flavonoid compounds has profound significance. In this work, the quercetin molecularly imprinting polymer (QMIP) was successfully prepared, in which a typical flavonol quercetin was selected as the template molecule. QMIP was synthesized by performing the surface molecular imprinting technology on the surface of NH2-MIL-101(Fe). Our study results showed that QMIP exhibited quick binding kinetic behavior, a high adsorption capacity (57.04[Formula: see text]mg/g), and the specific recognition ability toward quercetin compared with structurally distinct compounds (selective [Formula: see text]). The specific adsorption ability of quercetin by QMIP was further explained using computation simulation that molecules with non-planar 3D conformations hardly entered the molecularly imprinted cavities on QMIP. Finally, QMIP was successfully used for the specific extraction of quercetin and five other flavonol and flavonoid compounds in the crude extracts from Sapium sebiferum. This study proposes a new strategy to synthesize the molecularly imprinted polymer based on a single template for enriching and loading a certain class of active ingredients with similar core structures from variable botanicals.

Constructing electrochemical sensor using molecular-imprinted polysaccharide for rapid identification and determination of l-tryptophan in diet.

An imbalance of l-tryptophan (l-Trp), a basic component of a healthy diet, is harmful to human health. Traditional methods for detecting l-Trp have many limitations. To correct a deficiency or excess of l-Trp in human diets, it is necessary to develop a novel method that is rapid, low-cost, and high-sensitivity. Herein, a molecularly imprinted polysaccharide electrochemical sensor termed MIP/CS/MWCNTs/GCE (molecularly imprinted polymer/chitosan/multiwalled carbon nanotubes/glassy carbon electrode) targeting l-Trp was first constructed on a glassy carbon electrode, which was modified with multiwalled carbon nanotubes and chitosan using bifunctional monomers. The MIP/CS/MWCNTs/GCE obtained a wide linear range (1-300 µM) for detecting l-Trp and accurately detected the proportion of l-Trp in mixtures of Trp enantiomers. In milk samples, the spiked recoveries of l-Trp were 86.50 to 99.65%. The MIP/CS/MWCNTs/GCE electrochemical sensor possessed good recognition and detection performance for l-Trp and has promising potential for practical application.

Synergistic recognition of transferrin by using performance dual epitope imprinted polymers.

Transferrin (Trf) is a new type of active drug targeting carrier and disease biomarker that regulates the balance of iron ions in human body. The recognition and isolation of Trf is of great significance for disease diagnosis and treatment. Thus, a new type of magnetic dual affinity epitope molecularly imprinted polymer coated on Fe3O4 nanoparticles (Fe3O4@DEMIP) was successfully prepared for specific recognition of Trf. C-terminal nonapeptide and Trf glycan were selected as bi-epitope templates for metal chelation and boron affinity immobilization, respectively. 4-vinylphenylboric acid (4-VP), N-isopropyl acrylamide (NIPAM) and zinc acrylic were used as functional monomers. Results showed that Fe3O4@DEMIP exhibited excellent specific recognition ability adsorption capacity toward Trf, with an adsorption of 43.96 mg g-1 (RSD = 3.28%) and a more satisfactory imprinting factor (about 6.60) than that of other reported imprinting methods. In addition, Fe3O4@DEMIP displayed pH, temperature and magnetic sensitivity properties to realize temperature and pH-controlled recognition and release of target proteins and magnetic rapid separation. Furthermore, the Fe3O4@DEMIP coupled with high-performance liquid chromatography (HPLC) analysis was successfully used for specific recognition of Trf in biosamples. This study provides a reliable protocol for preparing metal chelation and boron affinity dual affinity bi-epitope molecularly imprinted polymers for synergistic and efficient recognition of biomacromolecules in the complex biological systems.

Selective separation and inexpensive purification of paclitaxel based on molecularly imprinted polymers modified with ternary deep eutectic solvents.

Paclitaxel (PTX) is a powerful anticancer natural product, with its separation and purification having been widely studied. In this work, new molecular imprinted polymers (MIPs) using deep eutectic solvents (DESs) with different molar ratios were prepared as functional monomers. These were then used as adsorbents in solid phase extraction (SPE) for the separation of PTX from its structural analogs. The polymers were characterized by energy disperive X-rays (EDX), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and fourier transform infrared spectroscopy (FT-IR). The results suggested that the formative regular DES-MIPs had an even pore-size distribution and a large specific surface area. The dynamic adsorption and static adsorption showed that the DES-MIPs had excellent adsorption performance, with a maximum adsorption capacity and optimum adsorption time of 87.08 mg/g and 180 min, respectively. The selective adsorption experiments showed that the material had outstanding selectivity, and the maximum selectivity factor was 6.20. For stability, after six consecutive adsorption and desorption cycles, the DES-MIPs maintained the perfect stability and reusability. Furthermore, the fabricated SPE column was successfully utilized for extracting and eluting PTX. This study provides a reliable protocol for the separation and purification PTX from its structural analogs and the DES-MIPs materials have excellent potential application value in pharmaceutical industry.

Simultaneous extraction of several targets by using non-toxic dual template molecularly imprinted polymers in vivo and in vitro.

In this report, a non-toxic Dual Template Molecularly Imprinted Polymers (DMIPs) was synthesized with quercetin and schisandrin b as template molecules, using deep-eutectic solvents as functional monomers for the first time. The DMIPs were used to efficiently and simultaneously enrich quercetin and schisandrin b from the mixed crude extracts of penthorum and schisandra. The results indicated that the DMIPs exhibited rapid adsorption kinetics (80 min for adsorption equilibrium) and high selectivity. The largest adsorbing capacities to quercetin and schisandrin b were 23.58 mg/g and 41.64 mg/g, respectively. After presaturation with quercetin and schisandrin b, the nontoxic saturated DMIPs were fed to the mice. Blood samples of the mice were taken and both quercetin and schisandrin b were successfully detected. The pharmacokinetics of quercetin and schisandrin b were similar to reports in the literature where mice were directly fed with botanicals. Our study provides a reliable protocol such that DMIPs can be used to separate and enrich several target molecules simultaneously from complex biological systems. Our findings suggested that the DMIPs have potential application as a drug delivery system of compound herbal formulas.