Organic Monoliths Research Articles

Fast quantitative determination of monoclonal antibody in infusion bags using protein A nano liquid chromatography

AbstractStaphylococcus aureus Protein A was immobilized on an in‐house made neutravidin poly (glycidyl methacrylate‐co‐ethylene dimethacrylate) capillary column with a 25 µm internal diameter, a length of 30 mm and a mass loadability of 60 ng. The immobilized quantity of protein A on the organic monolith was very low, in the pico mole range (1.80 pmol). This was of significance importance when working with less available or expensive purified enzyme. This capillary column was integrated into a nano liquid chromatographic system and used for the fast determination without dilution of the doses of therapeutic monoclonal antibodies (mAbs) in standardized infusion bags prepared in advance in a pharmacy department. This chromatographic method was linear in the studied concentration range with good precision and accuracy. Heat stressed studies indicated that the protein A affinity capillary column was able to monitor degraded mAbs. As well, the high specificity of this column to capture immunoglobulin G2 in cell culture supernatant was visualized. As the mAbs are produced through genetic engineering of animal cells this last result demonstrated that this novel protein A column could be used in the feature for rapid screening of immunoglobulin G concentration in cell culture.

Crystalline organic monoliths with bicontinuous porosity.

Organic crystals are a promising class of materials for various optical applications. However, it has been challenging to make macroscopic organic crystals with bicontinuous porosity that are applicable to flow chemistry. In this study, a new class of porous materials, cm-scale crystalline organic monoliths (COMs) with bicontinuous porosity, are synthesized by replicating the porous structure of silica monolith templates. The COMs composed of p-terphenyl can take up more than 30 wt% of an aqueous solution, and the photophysical properties of the p-terphenyl crystals are well maintained in the COMs. The relatively high surface area of the COMs can be exploited for efficient Dexter energy transfer from triplet sensitizers on the pore surface. The resulting triplet excitons in the COMs encounter and annihilate, generating upconverted UV emission. The COMs would open a new avenue toward applications of organic crystals in flow photoreaction systems.

Optimization of the Preparation of Hydrophilic Poly(DHPMA-co-MBA) Monolithic Capillary Columns: A New Support for Affinity Chromatography

In miniaturized affinity chromatography, the development of hydrophilic organic monoliths with reduced non-specific interactions and high-protein grafting capacity remains a hot topic. In this work, we propose the one-step synthesis of a diol organic monolith to replace the gold-standard epoxy-based organic monoliths (which require post-modification, namely hydrolysis, prior to use). The synthesis of this new monolith builds upon the use of N-N’-Methylenebis(acrylamide) (MBA), as a hydrophilic crosslinker, and 2,3-dihydroxypropyl methacrylate (DHPMA), a diol monomer that eliminates the time-consuming epoxy ring opening step and its associated side reactions. The optimization of one-step synthesis parameters led to a monolith with a satisfactory permeability ((4.8 ± 0.5) × 10−14 m2), high efficiency (117,600 plates/m at optimum flow velocity (uopt = 0.09 cm s−1)) and reduced non-specific interactions. It is exemplified by its separation ability in the HILIC mode (separation of nucleosides), and by the retention data set of 41 test solutes, which were used to evaluate the non-specific interactions. This new poly(DHPMA-co-MBA) monolith has not only hydrophilic surface properties, but also improved protein grafting capacity compared to the glycidyl-based monolith (13 ± 0.7 pmol cm−1). The potential of this monolith is illustrated in affinity chromatography, where the concanavalin ligands are ranked according to their Kd values.

A monolithic composite based on zeolite-like metal-organic framework@divinylbenzene polymer separates azeotropic fluorocarbon mixture efficiently

Organic monolithic columns are mainly used to separate macromolecules; however, many attempts to extend their performance toward small molecules were examined by incorporating micro- and nanoparticles. The incorporation technique enabled utilizing organic monoliths in gas chromatography (GC) for small molecules, which are still scarce. Here, we prepared a composite matrix of capillary monolithic columns of a zeolite-like metal-organic framework with a sodalite topology (sod-ZMOF) and Divinylbenzene polymer (DVB) for GC separations under 0.5 MPa. Relatively short DVB monolithic columns (18 cm long × 0.25 mm i.d.) incorporated with a tiny amount of sod-ZMOF nanoparticles (0.7 and 1.17 wt%) with an average particle size of 225 nm were successfully fabricated and used to separate linear alkanes and polar probes mixtures with increasing resolution up to 3.7 and 5.1 times, respectively, compared to a blank DVB monolithic column. A high-performance separation of linear alkanes series mixture (methane to decane) was exhibited in less than 2 min. McReynolds constants revealed that sod-ZMOF provided the composite monolith with a nonpolar character yielding a negative average polarity value smaller than the standard squalene column. An Excellent retention time of pentane and octane day-to-day reproducibility was achieved during 16 days and over more than 500 runs with RSD% of 2.25% and 3.3% using a composite monolithic column with 5 mg mL−1 sod-ZMOF (5-ZMOF@DVB). In addition, a qualitative determination of the gas mixture content of three commercially available Lighter gas cartridges was performed via the 5-ZMOF@DVB column. Finally, successfully separating an azeotropic freon mixture of difluoromethane (R-32) and pentafluoroethane (R-125) was achieved with a selectivity of up to 4.84. A further thermodynamic study related the preferential adsorption of R-125 to entropic factors rather than enthalpic while trapping inside ZMOF pores. This work sheds light on utilizing the infinite diversity of MOFs and combining their properties with high permeability and easily fabricated organic monoliths for GC separations of light molecules and gasses. Furthermore, the study highlights the role of GC as an easy and fast approach for the preliminary evaluation of the separation efficiency of porous polymers.

Polymer monoliths for the concentration of viruses from environmental waters: A review.

Even at low concentrations in environmental waters, some viruses are highly infective, making them a threat to human health. They are the leading cause of waterborne enteric diseases. In agriculture, plant viruses in irrigation and runoff water threat the crops. The low concentrations pose a challenge to early contamination detection. Thus, concentrating the virus particles into a small volume may be mandatory to achieve reliable detection in molecular techniques. This paper reviews the organic monoliths developments and their applications to concentrate virus particles from waters (waste, surface, tap, sea, and irrigation waters). Free-radical polymerization and polyaddition reactions are the most common strategies to prepare the monoliths currently used for virus concentration. Here, the routes for preparing and functionalizing both methacrylate and epoxy-based monoliths will be shortly described, following a revision of their retention mechanisms and applications in the concentration of enteric and plant viruses in several kinds of waters.

Immobilization of cellulase on monolith supported with Zr(IV)-based metal-organic framework as chiral stationary phase for enantioseparation of five basic drugs in capillary electrochromatography.

Metal-organic framework (UiO-66-NH2)-incorporated organic polymer monolith was prepared by thermal polymerization. By virtue of the superior physical and chemical properties, the UiO-66-NH2-modified organic monolith was then functionalized by chiral selector cellulase via the condensation reaction between the primary amino groups and aldehyde groups. The synthesized materials were characterized by Fourier transform infrared spectroscopy, high-resolution transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectrometry, thermogravimetric analysis, and nitrogen sorption isotherm. The cellulase@poly(glycidyl methacrylate-UiO-66-NH2-ethylene glycol dimethacrylate) (cellulase@poly(GMA-UiO-66-NH2-EDMA)) monolith was applied to enantiomerically separate the basic racemic forms of metoprolol, atenolol, esmolol, bisoprolol, and propranolol. In contrast to the cellulase@poly(GMA-co-EDMA) monolith without UiO-66-NH2, the cellulase@poly(GMA-UiO-66-NH2-EDMA) monolith reveals significantly improved enantiodiscrimination performance for metoprolol (Rs: 0 → 1.67), atenolol (Rs: 0 → 1.50), esmolol (Rs: 0 → 1.52), bisoprolol (Rs: 0 → 0.36), and propranolol (Rs: 0 → 0.44). The immobilization pH of cellulase, buffer pH, UiO-66-NH2 concentration, and the proportion of organic modifier were evaluated in detail with enantiomerically separating chiral molecules. The intra-day, inter-day, column-to-column, and inter-batch precision have been discussed, the result was preferable, and the relative standard deviation (RSD) of separation parameters was <4.3%. Schematic representation of the preparation of a UiO-66-NH2-modified organic polymer monolith for enantioseparating five racemic β-blockers. UiO-66-NH2 was synthesized and converted into a monolith as the stationary phase. Then, the modified monolith containing cellulase as the chiral selector was applied in a capillary electrochromatography system for enantioseparating chiral drugs.

Development of a new nano arginase HPLC capillary column for the fast screening of arginase inhibitors and evaluation of their binding affinity

A simple and rapid Nano LC method has been developed for the screening of arginase inhibitors. The method is based on the immobilization of biotinylated arginase on a neutravidin functionalized nano HPLC capillary column. The arginase immobilization step performed by frontal analysis is very fast and only takes a few minutes. The miniaturized capillary column of 170 nL (length 5 cm, internal diameter 75 μm) significantly decreased the required amount of used enzyme (25 pmol). This was of significance importance when working with less available or expensive purified enzyme. Non-selective adsorption of the organic monolith matrix was reduced (<6%) and the arginase efficient yield was high (92%). The resultant affinity capillary columns showed excellent repeatability and long lifetime. The arginase reaction product was achieved within 60 s and the immobilized arginase retained 97% of the initial activity beyond 90 days. This novel approach can thus be used for the fast evaluation of recognition assay induced bya series of inhibitor molecules (caffeic acid phenylamide, chlorogenic acid, piceatannol, nor-NOHA acetate) and plant extracts.

Three-Dimensional Nanoporous Covalent Organic Framework-Incorporated Monolithic Columns for High-Performance Liquid Chromatography

The application of three-dimensional covalent organic frameworks (3D COF) with complex structure and high stability as the stationary phase is promising for high-performance liquid chromatography (HPLC) but is still limited by their irregular shape and wide size distribution. Herein, we show the fabrication of the first 3D COF-based monolithic column via the facile incorporation of nanoporous 3D-IL-COF-1 consisting of tetrakis(4-formylphenyl)methane and p-phenylenediamine into a porous organic monolith for HPLC. The effect of essential factors including temperature, porogen, and 3D-IL-COF-1 on the column permeability and efficiency is systematically investigated via the orthogonal experiment. The uniform structure, good permeability, and high mechanical stability of the prepared 3D-IL-COF-1 monolithic column not only make it promising for broad-spectrum chromatographic separation of neutral, acidic, and basic compounds but also render it better separation of isomers than a C18 column. This work offers a facile strategy for synthesis of a 3D COF stationary phase and will largely expand the high potential of 3D COF in HPLC.

Incorporation of silver stearate nanoparticles in methacrylate polymeric monoliths for hemeprotein isolation

AbstractA unique method was used to synthesize extremely stable silver stearate nanoparticles (AgStNPs) incorporated in an organic-based monolith. The facile strategy was then used to selectively isolate hemeproteins, myoglobin (Myo) and hemoglobin (Hb). Ethyl alcohol, silver nitrate, and stearic acid were, respectively, utilized as reducing agents, silver precursors, and capping agents. The color changed to cloudy from transparent, indicating that AgStNPs had been formed. AgStNP nanostructures were then distinctly integrated into the natural polymeric scaffold. To characterize the AgStNP–methacrylate polymeric monolith and the silver nanoparticles, energy-dispersive X-ray (EDX), scanning electron microscopy (SEM), and Fourier-transform infrared (FT-IR) spectroscopy were used. The results of the SEM analysis indicated that the AgStNP–methacrylate polymeric monolith’s texture was so rough in comparison with that of the methacrylate polymeric monolith, indicating that the extraction process of the monolith materials would be more efficient because of the extended surface area of the absorbent. The comparison between the FT-IR spectra of AgStNPs, the bare organic monolith, and AgStNP–methacrylate polymeric monolith confirms that the AgStNPs were immobilized on the surface of the organic monolith. The EDX profile of the built materials indicated an advanced peak of the Ag sequence which represented an Ag atom of 3.27%. The results therefore established that the AgStNPs had been successfully integrated into the monolithic materials. Extraction efficiencies of 92% and 97% were used to, respectively, recover preconcentrated Myo and Hb. An uncomplicated method is a unique approach of both fabrication and utilization of the nanosorbent to selectively isolate hemeproteins. The process can further be implemented by using other noble metals.

Ground Organic Particles of ca. 3 μm Size as Chromatographic Separation Media in High Performance Liquid Chromatography

A new chromatographic stationary phase was prepared by making a soft organic monolith based on thermal polymerization of methyl methacrylate and ethylene glycol di-methacrylate with an aid of gas evolution via decomposition of urea, and by crushing the monolith into particles. The original purpose of urea incorporation was formation of monolith particles with affluent mesopores, but the actual effect was reduction of the particle size to a proper range (mostly in the range of 1–5 μm with an average of ca. 3 μm), which was very crucial for improvement of separation efficiency. A series of washing processes (including common washing and reflux washing) were carried out to remove un-reacted materials and free oligomers. The columns were made by packing the organic monolith particles in glass-lined stainless-steel tubing and evaluated for their performance with the mixture of six aromatic compounds (3-phenyl-1-propanol, acetophenone, methyl benzoate, 2-nitroaniline, ethylbenzene, cumene). The overall number of theoretical plates (N) over 6 analytes based on 6 columns was 32,000 plates/column (107,000 plates/m, 9.4 µm plate height).

Eco-friendly production of metal nanoparticles immobilised on organic monolith for pepsin extraction

Abstract Polymer monoliths modified by using nanoparticles (NPs) integrate high NP specific surface area with different monolith surface chemistry and high porosity. As a result, they have extensive applications within different fields, whereas nanomaterial-functionalised porous polymer monoliths have elicited considerable interest from investigators. This study is aimed at fabricating organic polymer-based monoliths from polybutyl methacrylate-co-ethylenedimethacrylate (BuMA-co-EDMA) monoliths prior to immobilization of gold or silver metal on the pore surface of the monoliths using reducing reagent (extracts of lemon peels). This was intended to denote a sustainable technique of immobilizing nanoparticles that are advantageous over physical and chemical techniques because it is safe in terms of handling, readily available, environmentally friendly, and cheap. Two different methods were used in the study to effectively immobilize nanoparticles on monolithic components. The outcomes showed that soaking the monolith rod in the prepared nano solution directly and placing it within ovens at temperatures of 80°C constituted the most effective method. Characterisation of the fabricated monolith was undertaken using SEM/EDX analysis, UV-vis. spectra analysis, and visual observation. The SEM analysis showed that nanoparticles were extensively immobilised on the surface polymers. Another peak was attained through EDX analysis, thus confirming the Au atom existence at 2.83% alongside another peak that proved the Ag atom existence at 1.92%. The fabricated components were used as sorbents for purifying protein. The ideal performance was achieved using gold nanoparticles (GNPs) immobilised organic monolith that attained a greater pepsin extraction recovery compared to silver nanoparticles (SNPs) immobilised organic monoliths alongside bare organic-based monolith.

Development of Ground Organic Monolith Particles as Packing Material in High Performance Liquid Chromatography

Organic monolith particles and their chromatography performance.

Robust immobilized enzyme reactor based on trimethylolpropane trimethacrylate organic monolithic matrix through “thiol-ene” click reaction

A novel immobilized enzyme reactor (IMER) based on trimethylolpropane trimethacrylate (TRIM) organic monolith was prepared by “thiol-ene” click reaction. The IMERs were made by fabricating TRIM monolith core in advance. There were residual double bonds on the surface of TRIM monolith, in which click reaction can be performed with the free thiol groups of trypsin at room temperature to bond the trypsin on the monolithic column without additionally introducing an active functional group. The enzyme activity was characterized by kinetic parameters Km and Vmax and determined by off-line chromatography. The performance of the IMERs was evaluated by digesting standard protein BSA and compared with in-solution digestion method. By using IMER 5 min, the sequence coverage rate of BSA was 79.41%, which was similar to that in-solution digestion for 12 h (82.7%). The applicability of the IMERs in complex samples was assessed by digesting crude protein extracts from egg white and mouse liver, identifying 28 (104 peptides) and 843 (3916 peptides) proteins, respectively. All results indicated that the IMERs have great potential in high-throughput proteomics analysis.

Development of a New Solid Phase Extraction Cartridge Filled with Organic Monolith Particles for Extraction of di‐Alkyl Phthalates

Development of a New Solid Phase Extraction Cartridge Filled with Organic Monolith Particles for Extraction of di‐Alkyl Phthalates

Monolith weak affinity chromatography for μg-protein-ligand interaction study

Affinity monolith columns of 375 nL (effective length 8.5 cm, internal diameter 75 μm) were developed for protein-ligand affinity investigations needing only 3 μg of human serum albumin (HSA). To promote specific interactions and avoid non-specific ones, different combinations of monolithic supports and bio-functionalization pathways were evaluated. Silica and glycidylmethacrylate based monoliths were in-situ synthesized and grafted with HSA. Two direct grafting methods epoxy-amine and Schiff Base plus the streptavidin-biotin method were compared. The columns were evaluated by frontal analysis with ligands of known affinity for HSA. It is shown that a classical capillary electrophoresis instrument equipped with an external pressure device can be used to do weak affinity chromatography at low pressure (less than 1.2 MPa) in a fully automated way and with very low reagent consumption. The grafting pathways were compared in terms of (i) total and active amounts of immobilized protein, (ii) non-specific interactions, (iii) protein denaturation. According to these criteria, the organic monoliths combined with the streptavidin-biotin approach provided the best results. This immobilization pathway led to the highest active protein content (40 pmol of HSA per 8.5-cm column) with less than 10% non-specific interactions and 84% protein activity. The target grafting step lasts only 10 min and is UV-monitored, the UV breakthrough curve giving the exact amount of bound protein. This novel approach was validated by Kd measurements of 3 known ligands of HSA. Streptavidin generic monolith columns could be stored at 4 °C for 3 months maintaining activity. μg of a biotin modified sensitive protein could be attached to a stable streptavidin monolith for immediate interaction studies avoiding stability problems. This development was subsequently extended to another protein of higher pharmaceutical interest: the N-terminal domain of HSP90. Affinity was measured for two known ligands and determined Kd values were in accordance with the literature, proving that our technique is applicable to other proteins.

Synthesis of Hybrid Monolithic Columns Using a Click Chemistry Reaction for Application in Capillary Liquid Chromatography

Hybrid monolithic columns present characteristics of both silica and organic monoliths, such as good mechanical properties, wide pH tolerance, high permeability and stability and little swelling or shrinkage. A common way to prepare this type of material is by using alkoxysilanes and organic monomers via the sol-gel process and click chemistry reactions. In this paper, a co-condensation organic-silica hybrid monolith was prepared based on tetramethoxysilane (TMOS) and vinyltrimethoxysilane (VTMS) as precursors for the sol-gel process. The hybrid monolithic matrix was modified with dodecanethiol through the thiol-ene click chemistry reaction and the resulting material was compared with a dodecanesilane bonded phase column, in order to evaluate the differences in the chromatographic performance of a stationary phase prepared by a classic reaction or by a thiol-ene click reaction. Additionally, the stability of the thiol-ene column over time was evaluated. The effects of different synthetic proportions were investigated in detail by scanning electron microscopy (SEM), scanning capacitively coupled contactless conductivity detection (sC4D), Fourier-transform infrared spectroscopy (FTIR) and retention behavior in capillary liquid chromatography (cLC). The hybrid monolithic column prepared with dodecanethiol was the best one for the separation of alkylbenzenes and polycyclic aromatic hydrocarbons by cLC-UV.

Porous carbon monoliths with pore sizes adjustable between 10 nm and 2 μm prepared by phase separation – New insights in the relation between synthesis composition and resulting structure

Porous carbon monoliths with tunable porosity are promising materials for a variety of applications like energy storage and adsorption. But the synthesis of carbons with monolithic shape and controlled porosity is often time-consuming and expensive. Here, micro-/macroporous and micro-/mesoporous carbon monoliths were synthesized via a simple process of polymerization induced phase separation of resorcinol and formaldehyde followed by drying at ambient pressure and carbonization. The carbon monoliths are mechanically stable and exhibit specific surface areas between 390 and 1100 m2·g−1. The size of the macro- and mesopores can be tailored over a wide range from approximately 10 nm to 2 μm by simply altering the solvent composition during the synthesis of the organic monoliths. The influence of solvent composition and resorcinol concentration on the pore size in the carbon monoliths was investigated with a focus on the smaller pore sizes and an exponential relation was observed. Finally, selected monoliths were activated in a stream of CO2 to produce hierarchically porous monoliths with specific surface areas between 1000 and 2400 m2·g−1. The activated monoliths were characterized in terms of their CO2 adsorption and showed adsorption capacities of up to 3.10 mmol·g−1 at 298 K.

One-pot preparation of an organic polymer monolith by thiol-ene click chemistry for capillary electrochromatography.

A novel organic monolith was successfully fabricated by a one-pot thiol-ene click reaction of triallyl isocyanurate with pentaerythritol tetrakis-(2-mercaptoacetate) and mercaptopropionic acid in the presence of porogens. We investigated the effects of the ratio of monomer and cross-linking agent, the type and ratio of porogen, and click reaction temperature on the permeability and morphology of the prepared poly triallyl isocyanurate-co-pentaerythritol tetrakis (2-mercaptoacetate) monoliths. The monolith was also characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The results indicated that the monoliths had continuous porous framework, good permeability, and high mechanical stability. A series of analytes with different properties such as alkylbenzenes, polycyclic aromatic hydrocarbons, anilines, and phenols were used to evaluate the electrochromatographic performance of the prepared monoliths in pressurized capillary electrochromatography. The prepared polymer monolith showed typical reversed-phase electrochromatographic behavior for hydrophobic substances. Moreover, the prepared monolith showed a mix of reversed-phase and cation exchange interaction modes for basic aniline compounds. The minimum plate height of the monolith was 8.76μm (132100 plates/m) for propylbenzene. These results demonstrated that one-pot thiol-ene click chemistry can provide a simple and reliable method for the preparation of organic monoliths.

Novel solid-state luminous composites from a layered inorganic–organic monolith containing neutral porphyrins

We have succeeded in loading a neutral zinc porphyrin derivative (ZnTPPder) into a layered inorganic–organic compound, despite the well-known difficulties associated with incorporation of neutral pigments into the interlayer spaces of layered materials. We have utilized a synthetic alkylammonium–smectite monolith (A-Sm) as the host layered inorganic–organic compounds to facilitate porphyrin loading. Alkylammonium groups are located between the layers of the phyllosilicate-analogue moieties (the inorganic moiety) bonding covalently with the inorganic moiety to form the monolith. The interlayer space of A-Sm is organophilic and swells in organic solvents. ZnTPPder was loaded into A-Sm by mixing A-Sm and solutions of ZnTPPder in organic solvents under different conditions yielding ZnTPPder/A-Sm composite films. UV–VIS measurements revealed several absorption peaks assigned to the characteristic Soret (432 nm) and Q (500–650 nm) bands of ZnTPPder for all the prepared ZnTPPder/A-Sm composite films. Fluorescence emission due to ZnTPPder was observed from all the ZnTPPder/A-Sm composite films, while a reference ZnTPPder/Sm cast film prepared from ZnTPPder and a smectite (Sm) rather than A-Sm was only weakly fluorescent. This emission behaviour suggests that ZnTPPder is intercalated in the interlayer space of A-Sm with suppression of aggregation of ZnTPPder. In contrast, ZnTPPder was hardly intercalated into the interlayer space of Sm. Thus, we have demonstrated a novel and relatively easy route for loading of neutral (uncharged) pigments into a solid-state two-dimensional nanospace, a method which might be applied to prepare novel light-harvesting systems.

Application of Organic Monolithic Materials to Enantioseparation in Capillary Separation Techniques.

This review article is primarily focused on the state-of-the-art of enantioseparations on organic monolithic materials. The article gives an overview of the chiral stationary phases and its application in capillary electrochromatography (CEC), and capillary- and nano-liquid chromatography (cLC and nLC). Since thousands of publications have been emerged from 2000's and citing all these papers would extend the scope of this review; then, recent developments from last 10 years (2006 to 2016) will be mentioned. Mostly, stationary phases based on copolymers obtained from chiral functional monomers and surface modifications of organic monoliths with chiral ligands will be discussed. The effective application of these chiral separation methodologies in several analysis areas will be also included.