Biomimetic immobilization of α-glucosidase inspired by antibody-antigen specific recognition for catalytic preparation of 4-methylumbelliferone

Immobilization technology plays an important role in enhancing enzyme stability and environmental adaptability. Despite its rapid development, this technology still encounters many challenges such as enzyme leakage, difficulties in large-scale implementation, and limited reusability. Drawing inspiration from natural paired molecules, this study aimed to establish a method for immobilized α-glucosidase using artificial antibody-antigen interaction. The proposed method consists of three main parts: synthesis of artificial antibodies, synthesis of artificial antigens, and assembly of the artificial antibody-antigen complex. The critical step in this method involves selecting a pair of structurally similar compounds: catechol as a template for preparing artificial antibodies and protocatechualdehyde for modifying the enzyme to create the artificial antigens. By utilizing the same functional groups in these compounds, specific recognition of the antigen by the artificial antibody can be achieved, thereby immobilizing the enzymes. The results demonstrated that the immobilization amount, specific activity, and enzyme activity of the immobilized α-glucosidase were 25.09 ± 0.10 mg/g, 5.71 ± 0.17 U/mgprotein and 143.25 ± 1.71 U/gcarrier, respectively. The immobilized α-glucosidase not only exhibited excellent reusability but also demonstrated remarkable performance in catalyzing the hydrolysis of 4-methylumbelliferyl-α-D-glucopyranoside.

Recent Advances in Molecularly Imprinted Polymers and Their Disease-Related Applications

Molecularly imprinted polymers (MIPs) and the imprinting technique provide polymeric material with recognition elements similar to natural antibodies. The template of choice (i.e., the antigen) can be almost any type of smaller or larger molecule, protein, or even tissue. There are various formats of MIPs developed for different medical purposes, such as targeting, imaging, assay diagnostics, and biomarker detection. Biologically applied MIPs are widely used and currently developed for medical applications, and targeting the antigen with MIPs can also help in personalized medicine. The synthetic recognition sites of the MIPs can be tailor-made to function as analytics, diagnostics, and drug delivery systems. This review will cover the promising clinical applications of different MIP systems recently developed for disease diagnosis and treatment.

Advancing the use of molecularly imprinted polymers in bioanalysis: the selective extraction of cotinine in human urine

Aim: To characterize a molecularly imprinted polymer via precipitation polymerization for the extraction of cotinine in urine. Methods: The polymer was created via precipitation polymerization. Physical characteristics of the polymer were assessed via scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis. The polymer adsorption capacity was assessed and an solid-phase extraction method from urine by LC-MS/MS was developed. Results: The polymer had small, spherical morphology and little thermal decomposition. The extraction method yielded cotinine recoveries of 77-103% in urine. The molecularly imprinted polymer adsorption capacity for cotinine was 448.2 ± 2.1 μg/mg. Common interferants did not affect cotinine's extraction. Conclusion: The resulting polymer was determined to be specific for cotinine and can be used for the detection of cotinine in urine for clinical samples.

Synthesis, column packing and liquid chromatography of molecularly imprinted polymers for the acid black 1, acid black 210, and acid Brown 703 dyes

Molecularly imprinted polymers have been synthesized for the acid black 1, acid black 210, and acid brown 703 dyes using methacrylic acid, ethylene glycol, and azobisisobutyronitrile as the monomer, cross-linker, and initiator, respectively, in the ratio of 1 : 10 : 44 (template:monomer:cross-linker). The MIPs were used for the selective removal of their corresponding dyes. The selective nature of the MIPs towards their respective dyes was confirmed by a homemade liquid chromatography system. The resultant polymer materials were packed in a stainless steel column and checked for the separation of mixtures of dyes in liquid chromatography. The dyes complementary in structure to the imprinted cavities in the MIPs had long retention times, showing the highly selective nature of the MIPs. The pH, quantity of the MIPs, time, and concentration of the dyes were optimized for the highly efficient removal of the newly synthesized MIP adsorbents in batch adsorption studies. First-order, second-order, and intra-particle diffusion models were applied to all the three MIP-based adsorbents for their kinetic investigations towards the dyes. All the three MIPs selectively absorbed their target template molecule in the presence of four other template dyes having closely related structures with % RSD < 4% for the three batch experiments. The synthesized MIPs were characterized by FTIR, SEM imaging and liquid chromatography. FTIR results strongly confirmed the presence of hydrogen bonding interactions (600–900) between the template and the individual monomers present in the unwashed MIPs. Liquid chromatography revealed the highly selective nature of the MIPs towards their template molecules. The synthesized polymeric substances possess excellent thermal, chemical, and mechanical stability and can be reused several hundred times. The MIPs were applied in the removal of dyes from spiked water samples (river water, tap water and distilled water) where the % removal of the dyes by their corresponding MIPs was greater than 90%.

MIP synthesis for the recently emerging dyes, a new method for their characterization in liquid chromatography by packing packing the MIP particles in a stainless steel column, and their application in environmental remediation.

Molecularly imprinted Monolithic column-based SERS sensor for selective detection of cortisol in dog saliva

Molecularly imprinted monolithic column embedded with silver nanoparticles (MIMC@Ag) was synthesized by in-situ polymerization with template and porogen inside capillary tube followed by silver precursor reduction and template/porogen removal for realizing Raman detection of cortisol. Dense silver nanoparticles generated within the monolith makes this kind of column suitable for surface enhanced Raman scattering (SERS) detection, designated as SERS-MIMC. Scanning electron microscopy and BET profiler confirmed larger pore structure in the column after template removal. The corresponding increased mass transfer/binding rate, selective adsorption and adsorptive mechanism of the MIMC were well studied with a series of adsorption experiments. The minimum Raman detectable concentration of cortisol is 1 × 10^-7 mol L^-1 by using MIMC@Ag with a good linear relationship in the concentration range from 1 × 10^-3 to 1 × 10^-7 mol L^-1. SERS sigmal of cortisol can be clearly distinguished from its analogs (estradiol, cholesterol and dexamethasone), proving the selective recognition of cortisol for SERS detection by MIMC@Ag. This ease-to-prepare SERS-MIMC sensor also shows good stability and reusability. The SERS-MIMC has been successfully applied for the easy, sensitive and selective detection of cortisol in dog saliva.

Molecularly imprinted monoliths: Recent advances in the selective recognition of biomacromolecules related biomarkers

Biomarkers are significant indicators to assist the early diagnosis of diseases and assess the therapeutic response. However, due to the low-abundance of biomarkers in complex biological fluids, it is highly desirable to explore efficient techniques to attain their selective recognition and capture before the detection. Molecularly imprinted monoliths integrate the high selectivity of imprinted polymers and the rapid convective mass transport of monoliths, and as a result are promising candidates to achieve the specific enrichment of biomarkers from complex samples. This review summarizes the various imprinting approaches for the preparation of molecularly imprinted monoliths. The state-of-art advances as an effective platform for applications in the selective capture of biomacromolecules related biomarkers were also outlined. This article is protected by copyright. All rights reserved.

Growing Trends in the Efficient and Selective Extraction of Compounds in Complex Matrices Using Molecularly Imprinted Polymers and Their Relevance to Toxicological Analysis

In the world of forensic and clinical toxicology, proper sample preparation is one of the key steps in identification and quantification of drugs of abuse. Traditional extraction methods such as solid-phase extraction and liquid-liquid extraction are often laborious and nonselective for the target analytes being measured. Molecularly imprinted polymers (MIPs) can be synthesized for sample extraction and their versatility allows the polymer to be employed in off-line, benchtop extractions or on/in-line instrument extractions, offering a faster and more selective sample preparation without the risk of interfering matrix effects. This review details the synthesis and applications of MIP materials for the extraction of drug compounds from biological matrices in publications from 1994 to today.

Macroporous Polymer Monoliths in Thin Layer Format

Nowadays, macroporous polymer monoliths represent widely used stationary phases for a number of dynamic interphase mass exchange processes such as high-performance liquid chromatography, gas chromatography, electrochromatography, solid-phase extraction, and flow-through solid-state biocatalysis. This review represents the first summary in the field of current achievements on the preparation of macroporous polymer monolithic layers, as well as their application as solid phases for thin-layer chromatography and different kinds of microarray.

Molecularly imprinted polymer-enhanced biomimetic paper-based analytical devices: A review

The popularization of paper-based analytical devices (PADs) in analytical science has fostered research on enhancing their analytical performance for accurate and sensitive assays. With their superb recognition capability and structural stability, molecularly imprinted polymers (MIPs) have been extensively employed as biomimetic receptors for capturing target analytes in various complex matrices. The integration of MIPs as recognition elements with PADs (MIP-PADs) has opened new opportunities for advanced analytical devices with elevated selectivity and sensitivity, as well as a shorter assay time and a lower cost. This review covers recent advances in MIP-PAD fabrication and engineering based on multifarious signal transduction systems such as colorimetry, fluorescence, electrochemistry, photoelectrochemistry, and chemiluminescence. The application of MIP-PADs in the fields of biomedical diagnostics, environmental analysis, and food safety monitoring is also reviewed. Further, the advantages, challenges, and perspectives of MIP-PADs are discussed.

Synthesis of a poly(sulfobetaine-co-polyhedral oligomeric silsesquioxane) hybrid monolith via an in-situ ring opening quaternization for use in hydrophilic interaction capillary liquid chromatography

An in-situ approach is described for synthesis of poly(sulfobetaine-co-polyhedral oligomeric silsesquioxane) [poly(sulfobetaine-co-POSS)] that can be used in a hybrid monolithic column as a hydrophilic liquid chromatography (HILIC) stationary phase. Synthesis involves (a) radical polymerization of octa(propyl methacrylate)-polyhedral oligomeric silsesquioxane (MA-POSS) and organic monomers such as dimethylaminopropyl methacrylate or vinyl imidazole, and (b) in-situ ring-opening quaternization between 1,4-butane sultone and the organic monomers. The sulfobetaine groups are generated in-situ monolith. This obviates the need for synthesis of sulfobetaine monomer previously. The pore size and permeability of the material can be tuned by using a binary porogenic system (polyethyleneglycol 600 and acetonitrile) and via the composition of the polymerization mixture. The optimized hybrid monolith owns its merits to the presence of POSS and sulfobetaine groups with good mechanical stability, the lack of residual silanol groups, and adequate hydrophilicity. The column filled with the monoliths was evaluated as a stationary phase for HILIC. Several kinds of polar compounds (including nucleosides, bases, phenols, aromatic acids and amides) were separated by using mobile phases with high organic solvent fractions in capillary liquid chromatography. Graphical abstractAn in-situ approach is described for synthesis of poly(sulfobetaine-co-polyhedral oligomeric silsesquioxane) hybrid monolithic column for use in hydrophilic liquid chromatography. The optimized monolith owns good mechanical stability, the lack of residual silanol groups and adequate hydrophilicity. Baseline separation of several kinds of polar compounds is achieved on the column. MA-POSS: octa(propyl-methacrylate) polyhedral oligomeric silsesquioxane; DMAEMA: dimethylaminoethyl methacrylate; AIBN: azodiisobutyronitrile. Poly(DMABS-co-POSS): poly(N-(4-sulfobutyl)-N-methacryloxypropyl- N,N-dimethylammonium-betaine-co-polyhedral oligomeric silsesquioxane).

Determination of sulfamerazine in aquatic products by molecularly imprinted capillary electrochromatography

A molecularly imprinted monolith was prepared and evaluated for the special selective separation of sulfamerazine (SMR) by capillary electrochromatography (CEC). The single-step in situ polymerization method was applied through thermally immobilized vinyl groups of itaconic acid and a derivatization capillary column using SMR as the template. The monolith with optimal selectivity and permeability was performed at 45°C for 7 h according to the molar ratios of 1 : 4 : 10 (template/functional monomer/cross-linker). Under the optimized separation conditions of 75% acetonitrile in 20 mM phosphate buffer with pH 5.0, 15 kV applied voltage and 20°C column temperature, the imprinted monolith showed strong recognition ability for SMR and high column performance. Finally, the molecularly imprinted monolith coupled with the CEC method was successfully developed for the quantification of SMR in aquatic products, which was properly validated by a good linear relationship, recoveries and limit of detection. The coupling technique of the molecularly imprinted technology and CEC achieved pre-treatment enrichment and separation analysis in only one miniaturized chromatographic column.

Microfluidic array surface ion-imprinted monolithic capillary microextraction chip on-line hyphenated with ICP-MS for the high throughput analysis of gadolinium in human body fluids

A novel method by hyphenating chip-based array ion-imprinted monolithic capillary microextraction with ICP-MS was proposed for the online analysis of trace Gd in biological samples.

Molecularly Imprinted Polymers as Extracting Media for the Chromatographic Determination of Antibiotics in Milk

Milk-producing animals are typically kept stationary in overcrowded large-scale farms and in most cases under unsanitary conditions, which promotes the development of infections. In order to maintain sufficient health status among the herd or promote growth and increase production, farmers administer preventative antibiotic doses to the animals through their feed. However, many antibiotics used in cattle farms are intended for the treatment of bacterial infections in humans. This results in the development of antibiotic-resistant bacteria which pose a great risk for public health. Additionally, antibiotic residues are found in milk and dairy products, with potential toxic effects for the consumers. Hence the need of antibiotic residues monitoring in milk arises. Analytical methods were developed for the determination of antibiotics in milk, with key priority given to the analyte extraction and preconcentration step. Extraction can benefit from the production of molecularly imprinted polymers (MIPs) that can be applied as sorbents for the extraction of specific antibiotics. This review focuses on the principals of molecular imprinting technology and synthesis methods of MIPs, as well as the application of MIPs and MIPs composites for the chromatographic determination of various antibiotic categories in milk found in the recent literature.

Evolution in miniaturized column liquid chromatography instrumentation and applications: An overview

The purpose of this article is to underline the miniaturized LC instrumental system and describe the evolution of commercially available systems by discussing their advantages and drawbacks. Nowadays, there are already many miniaturized LC systems available with a great variety of pump design, interface and detectors as well as efficient columns technologies and reduced connections devices. The solvent delivery systems are able to drive the mobile phase without flow splitters and promote gradient elution using either dual piston reciprocating or syringe-type pumps. The mass spectrometry as detection system is the most widely used detection system; among many alternative ionization sources direct-EI LC-MS is a promising alternative to APCI. In addition, capillary columns are now available showing many possibilities of stationary phases, inner diameters and hardware materials. This review provides a discussion about miniaturized LC demonstrating fundamentals and instrumentals' aspects of the commercially available miniaturized LC instrumental system mainly nano and micro LC formats. This review also covers the recent developments and trends in instrumentation, capillary and nano columns, and several applications of this very important and promising field.

Preparation and characterization of macroporous monoliths imprinted with erythromycin

The synthesis of macroporous molecularly imprinted monoliths was performed using the monomers system 2-hydroxyethyl methacrylate-ethylene glycol dimethacrylate and erythromycin as a template. The copolymerization was carried out in situ inside 50 mm × 4.6 mm i.d. stainless-steel tubing. The morphology of the monoliths was examined with scanning electron microscopy. The porous characteristics were determined both from the data of hydrodynamic permeability of monoliths and by means of mercury intrusion porosimetry. The retention parameters of target substance (erythromycin), values of calculated imprinting factors and apparent dynamic dissociation constants were obtained for monoliths prepared with the application of different amount of template (4, 8 and 12 mol%). The separations of the mixtures azithromycin/erythromycin and ciprofloxacin/erythromycin were demonstrated. Additionally, the possibility of erythromycin quantification in human blood plasma was shown.

Current trends in the development of molecularly imprinted polymers in CEC

This review focused on the developments in the field of molecularly imprinted polymers (MIPs) for CEC since 2009. New preparation techniques of MIP-based CEC, such as, portable microchip with macroporous monolithic imprinted microchannel, and low cross-linking MIPs based on liquid crystalline monomers, were discussed. Using selected cases rather than a comprehensive review of the entire field, our goal is to highlight the studies of the interest with an emphasis on recent work, and offers suggestions for future development in the field of imprinted materials for CEC separation.

Molecular imprinting science and technology: a survey of the literature for the years 2004-2011

Herein, we present a survey of the literature covering the development of molecular imprinting science and technology over the years 2004-2011. In total, 3779 references to the original papers, reviews, edited volumes and monographs from this period are included, along with recently identified uncited materials from prior to 2004, which were omitted in the first instalment of this series covering the years 1930-2003. In the presentation of the assembled references, a section presenting reviews and monographs covering the area is followed by sections describing fundamental aspects of molecular imprinting including the development of novel polymer formats. Thereafter, literature describing efforts to apply these polymeric materials to a range of application areas is presented. Current trends and areas of rapid development are discussed.

Facile preparation of organic-inorganic hybrid polymeric ionic liquid monolithic column with a one-pot process for protein separation in capillary electrochromatography

An organic-inorganic hybrid monolithic column based on 1-vinyl-3-dodecylimidazolium bromide (VC12Im(+)Br(-)) has been prepared in a single step by combining radical copolymerization with a non-hydrolytic sol-gel (NHSG) process. The NHSG process was significantly shortened to 6 h by using formic acid as catalyst. For comparison, we also prepared polymeric ionic liquid (PIL) monolithic columns by hydrolytic sol-gel and organic polymeric process, respectively. The resulting monolithic columns were characterized by Fourier transform infrared spectra, scanning electron microscopy, and Brunauer-Emmett-Teller. Under the capillary electrochromatography mode, these columns were applied to separate alkylbenzenes, anilines, and proteins, respectively. The results indicated that the NHSG-based hybrid PIL monolithic column exhibited the highest column efficiency among the three types of columns; organic solvent, commonly required by the traditional columns to achieve satisfactory separation efficiency for proteins, was absent in the NHSG-based hybrid PIL monolithic column because of the biocompatibility of the VC12Im(+)Br(-), which was beneficial to analysis of protein containing samples. In order to demonstrate its application potential, the developed NHSG-based hybrid PIL monolithic column was also employed to separate egg white sample.

Advance of CE and CEC in phytochemical analysis (2012–2013)

This article presents an overview of the advance of CE and CEC in phytochemical analysis, based on the literature not mentioned in our previous review papers [Chen, X. J., Zhao, J., Wang, Y. T., Huang, L. Q., Li, S. P., Electrophoresis 2012, 33, 168–179], mainly covering the years 2012–2013. In this article, attention is paid to online preconcentration, rapid separation, and sensitive detection. Selected examples illustrate the applicability of CE and CEC in biomedical, pharmaceutical, environmental, and food analysis. Finally, some general conclusions and future perspectives are given.

Molecularly Imprinted Hydrogels for Affinity-controlled and Stimuli-responsive Drug Delivery

The performance of smart or intelligent hydrogels as drug-delivery systems (DDSs) can be notably improved if the network is endowed with high-affinity receptors for the therapeutic molecule. Conventional molecular imprinting technology aims to create tailored binding pockets (artificial receptors) in the structure of rigid polymers by means of a template polymerization, in which the target molecules themselves induce a specific arrangement of the functional monomers during polymer synthesis. Adaptation of this technology to hydrogel synthesis implicates the optimization of the imprinting pocket to be able to recover the high-affinity conformation when distorted by swelling or after the action of a stimulus. This chapter analyzes the implementation of the molecular imprinting technology to the synthesis of both non-responsive and responsive loosely cross-linked hydrogels, and provides recent examples of the suitability of the imprinted networks to attain affinity-controlled, activation-controlled or stimuli-triggered drug and protein release.