Recognition and selective extraction of poly-γ-glutamic acid based on molecular imprinting technology

Characterization and optimization of magnetic molecularly imprinted nanofibers for determination of sunitinib in human serum and capsule samples

This article reports a spectrofluorometric method for the determination of sunitinib (STB) drug based on molecularly imprinted nanofibers fabricated by the electrospinning method and modified by magnetic nanoparticles as sorbent. The characterization of magnetic molecularly imprinted nanofibers (MMINs) was carried out using X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscopy (TEM), which confirmed the successful synthesis of MMINs with well-distributed magnetite nanoparticles. Drug adsorption and desorption were optimized and important parameters such as sample pH, nanofiber mass, adsorption and desorption time, eluent solvent and sample volume were analyzed. The results demonstrated that the MMINs act as a selective sorbent for STB and can be readily collected through an external magnetic field. Methanol was used as the best eluent solvent for STB desorption from MNIN. A linear correlation was observed between the STB concentrations and fluorescence intensities in the range of 0.01-15.0 mg L-1. The detection limit for this method was 0.002 mg L-1. The relative standard deviation (RSD) of 2.6 % for 1.0 mg L-1 and 1.1 % for 10 mg L-1 of STB (n = 3) were obtained, which indicates that the developed method is precise in determining STB. Human serum and capsule analysis show the applicability of the proposed sensor for real samples.

Design of pH-responsive molecularly imprinted polymer as a carrier for controlled and sustainable capecitabine release

A molecularly imprinting polymer (MIP) carrier with pH-responsivity was designed to construct a drug delivery system (DDS) focusing on controlled and sustainable capecitabine (CAPE) release. The pH-responsive characteristic was achieved by the functionalization of SiO2 substrate with 4-formylphenylboronic acid, accompanied by the introduction of fluorescein isothiocyanate for the visualization of the intracellular localization of the nanocarrier. Experimental results indicated that CAPE was adsorbed onto the drug carrier with satisfactory encapsulation efficiency. The controlled release of CAPE was realized based on the break of borate ester bonds between -B(OH)2 and cis-diols in the weakly acidic environment. Density functional theory computations were conducted to investigate the adsorption/release mechanism. Moreover, in vitro experiments confirmed the good biocompatibility and ideal inhibition efficiency of the developed DDS. The MIP can act as an eligible carrier and exhibits the great potential in practical applications for tumor treatment.

Layer-by-layer self-assembly embedding of nattokinase in chitosan/γ-polyglutamic acid: Preparation, fibrinolytic activity, stability, and in vitro digestion study

Nattokinase (NK) is a thrombolytic enzyme extracted from natto, which can be used to prevent and treat blood clots. However, it is sensitive to the environment, especially the acidic environment of human stomach acid, and its effect of oral ingestion is minimal. This study aims to increase NK's oral and storage stability by embedding NK in microcapsules prepared with chitosan (CS) and γ-polyglutamic acid (γ-PGA). The paper prepared a double-layer NK oral delivery system by layer self-assembly and characterized its stability and in vitro simulated digestion. According to the research results, the bilayer putamen structure has a protective effect on NK, which not only maintains high activity in various environments (such as acid-base, high temperature) and long-term storage (60 days), but also effectively protects the loaded NK from being destroyed in gastric fluid and achieves its slow release. This work has proved the feasibility of the design of bilayer putamen structure in oral administration and has good fibrolytic activity. Therefore, the novel CS/γ-PGA microcapsules are expected to be used in nutraceutical delivery systems.

Novel molecularly imprinted aerogels: Preparation, characterization, and application in selective separation for oleanolic acid in lingonberry

An oleanolic acid (OA) surface molecularly imprinted polymer silylated porous composite aerogels (OA-MIP@Si-PC-aerogels) adsorbent material was successfully prepared and characterized. The material not only has a great selectivity for the target molecule OA but also has other noteworthy qualities including high stability, excellent repeatability, and a sizable adsorption capacity. via cellulose and sodium alginate as the main materials, the carrier Si-PC-aerogels were made through ionic cross-linking, chemical cross-linking, and silylation procedures. By adopting a surface molecular imprinting approach on Si-PC-aerogels, OA-MIP@Si-PC-aerogels were effectively created utilizing OA as the template molecule and MAA as the functional monomer. Due to the presence of a specific imprinted layer on the aerogel surface, the adsorption capacity of OA-MIP@Si-PC-aerogels for OA could reach 66.20 mg g-1. OA-MIP@Si-PC-aerogels could achieve a 68.86% yield of OA from the extracts of lingonberry (Vaccinium Vitis-Idaea L.). The adsorption capacity remained at 90% after five consecutive adsorption-desorption cycles. HepG2 cells were exposed to OA that was effectively enriched with OA-MIP@Si-PC-aerogels in lingonberry (Vaccinium Vitis-Idaea L.) fruit homogenates. This OA significantly inhibited the growth of HepG2 cells in vitro. It further demonstrated that OA-MIP@Si-PC-aerogels could efficiently target OA enrichment and separation with good recovery.

A cellulose-based intelligent temperature-sensitive molecularly imprinted aerogel reactor for specific recognition and enrichment of ursolic acid

In this article, thermosensitive molecularly imprinted polymer and composite aerogel were combined for the first time to create an intelligent temperature-responsive aerogel reactor to effectively enrich ursolic acid (UA). Because aerogel carrier had a higher specific surface area and higher porosity compared to other carriers, the ursolic acid molecularly imprinted intelligent temperature responsive aerogel reactor (ITR&AR(G570)&UA-MIP) demonstrated a higher adsorption capacity for UA. More notably, ITR&AR(G570)&UA-MIP have the extraordinary capacity to spontaneously adsorb-desorb target molecule UA by regulating the reaction temperature. The ratio of the target molecule UA to the functional monomer and crosslinker in the grafting process and external influences had a major impact on how ITR&AR(G570)&UA-MIP were prepared overall. When the molar ratio of UA to 4-VP was 1:8, the weight ratio between ITR&AR(G570)&UA-MIP and EGDMA/DVB was 1:2:10, the reaction temperature was 60 °C, and the ambient pH = 6, the material showed the best adsorption capacity, reaching a peak of about 70 mg g-1. After researching the appropriate synthesis conditions, ITR&AR(G570)&UA-MIP were applied to lingonberry (Vaccinium Vitis-Idaea L.) berry extracts in this work. The outcomes show that this technique provides a new, intelligent, temperature-controlled adsorption material for the solid-phase extraction of triterpenoid acids in natural products, with good specific adsorption performance for the target molecule UA.

Tumor Microenvironment-Activated Hydrogel Platform with Programmed Release Property Evokes a Cascade-Amplified Immune Response against Tumor Growth, Metastasis and Recurrence

In situ tumor vaccines (ITV) have been recognized as a promising antitumor strategy since they contain the entire tumor-specific antigens, avoiding tumor cells from evading immune surveillance due to antigen loss. However, the therapeutic benefits of ITV are limited by obstacles such as insufficient antigen loading, inadequate immune system activation, and immunosuppressive tumor microenvironments (TME). Herein, a tumor microenvironment-activated hydrogel platform (TED-Gel) with programmed drug release property is constructed for cascaded amplification of the anti-tumor immune response elicited by ITV. Both doxorubicin (Dox) and cytosine-phosphate-guanosine oligodeoxynucleotides (CpG) are released first, in which Dox induces immunogenic tumor cell death causing additional tumor antigen release and leading the dying primary tumor cells into autologous tumor vaccine, and the released CpG promotes antigen presenting cell activation. Subsequently, the decomposed scaffold materials in conjunction with CpG, turn the anti-inflammatory M2-like macrophages into the M1 type, reversing the immunosuppressive TME. With decomposition of the TED-Gel, large amounts of macromolecule anti-PD-L1 antibodies are liberated, reinvigorating the exhausted effector T cells. In vivo studies demonstrate that TED-Gel significantly inhibits the primary, distant and rechallenged tumor growth. Overall, the simple and powerful TED-Gel provides an alternative strategy for the future development of tumor vaccines with broad application.

Preparation and Characterization of Protein Molecularly Imprinted Poly (Ionic Liquid)/Calcium Alginate Composite Cryogel Membrane with High Mechanical Strength for the Separation of Bovine Serum Albumin

In order to improve the mechanical strength and imprinting efficiency, a novel bovine serum albumin (BSA) molecularly imprinted poly(ionic liquid)/calcium alginate composite cryogel membrane (MICM) was prepared. The results of the tensile test indicated that the MICM had excellent mechanical strength which could reach up to 90.00 KPa, 30.30 times higher than the poly (ionic liquid) membrane without calcium alginate; the elongation of it could reach up to 93.70%, 8.28 times higher than the poly (ionic liquid) membrane without calcium alginate. The MICM had a very high welling ratio of 1026.56% and macropore porosity of 62.29%, which can provide effective mass transport of proteins. More remarkably, it had a very high adsorption capacity of 485.87 mg g-1 at 20 °C and 0.66 mg mL-1 of the initial concentration of BSA. Moreover, MICM also had good selective and competitive recognition toward BSA, exhibiting potential utility in protein separation. This work can provide a potential method to prepare the protein-imprinted cryogel membrane with both high mechanical strength and imprinting efficiency.

A novel electrochemiluminescence sensor based on a molecular imprinting technique and UCNPs@ZIF-8 nanocomposites for sensitive determination of imidacloprid

An MIT-ECL sensor for IM detection based on UCNPs@ZIF-8 nanocomposites.

A cellulose-based temperature sensitivity molecular imprinted hydrogel for specific recognition and enrichment of paclitaxel

A microcrystalline cellulose-based temperature sensitivity paclitaxel molecular imprinted hydrogel (MCC-TSMIHs-PTX) was successfully prepared by temperature-sensitive monomer N-isopropylacrylamide, functional monomer 4-vinylpyridine, cross-linking agent N, N'-methylenebisacrylamide and microcrystalline cellulose. They showed imprinting effective responses to the temperature changes. The results of adsorption kinetics, adsorption equilibrium, thermodynamics, selectivity and reusability showed the successful formation of a grafting thermosensitivity hydrogel with higher adsorption capacity and specific recognition. When the temperature reached 308 K, imprinting effect of hydrogel cavities would be most effective and conducive to capture template molecules. When the temperature reached 288 K, the lowest imprinting effect would facilitate the desorption of PTX. Finally, the MCC-TSMIHs-PTX was applied to enrich the paclitaxel in Taxus × media extracts samples, the relative contents of PTX in the samples were increased greatly from 7.23% to 78.32%, indicating the MCC-TSMIHs-PTX was a stable adsorption capacity for efficient separation and enrichment of PTX in Taxus × media extracts.