Methacrylate-based chromatographic media

All-atom modeling of methacrylate-based multi-modal chromatography resins for Langmuir constant prediction of peptides

In downstream processing, the intricate nature of the interactions between biomolecules and adsorbent materials presents a significant challenge in the prediction of their binding and elution behaviors. This complexity is further heightened in multi-modal chromatography (MMC), which employs two distinct binding mechanisms. To gain a deeper understanding of the involved interactions, simulating the adsorption of biomolecules on resin surfaces is a focal point of ongoing research. However, previous studies often simplified the adsorbent surface, modeling it as a flat or slightly curved plane without including a realistic backbone structure. Here, we introduce and validate two novel workflows aimed at predicting peptide binding behaviors in MMC, specifically targeting methacrylate-based resins. Our first achievement was the development of an all-atom model of a commercial MMC resin surface, incorporating its polymethacrylic backbone. Furthermore, we established and tested a workflow for rapid calculations of binding free energies (ΔG) with 10 linear peptides as target molecules. These ΔG calculations were effectively used to predict Langmuir constants, achieving a high coefficient of determination (R²) of 0.96. In subsequent benchmarking tests, our model outperformed established, simpler resin surface models in terms of predictive capabilities.

Influence of the Polymerization Parameters on the Porosity and Thermal Stability of Polymeric Monoliths

Rigid porous polymeric monoliths are robust, highly efficient, versatile stationary phases. They offer simple preparation and convenient modification provided by a whole range of synthesis factors, e.g., starting monomers, cross-linkers, initiators, porogens, polymerization techniques, and temperature. The main aim of this study was to synthesize polymeric monoliths and determine the correlation between polymerization parameters and the porosity and thermal stability of the obtained materials. Polymeric monoliths were synthesized directly in HPLC columns using N-vinyl-2-pyrrolidone (NVP) and 4-vinylpiridine (4VP) as functional monomers, with trimethylolpropane trimethacrylate (TRIM) serving as the cross-linking monomer. During copolymerization a mixture of cyclohexanol/decane-1-ol was used as the pore-forming diluent. Polymerization was carried out at two different temperatures: 55 and 75 °C. As a result, monoliths with highly developed internal structure were synthesized. The value of their specific surface area was in the range of 92 m2/g to 598 m2/g, depending on the monomer composition and polymerization temperature. Thermal properties of the obtained materials were investigated by means of thermogravimetry (TG). Significant differences in thermal behavior were noticed between monoliths synthesized at 55 and 75 °C. Additionally, the poly(NVP-co-TRIM) monolith was successfully applied in GC analyses.

Preparation of magnetic poly(ethylene glycol dimethacrylate-N-Methacryloyl-(L)-glutamic acid) particles for thrombin purification

In this study, magnetic poly(ethylene glycol dimethacrylate-N-methacryloyl-(L)-glutamic acid) (mPEGDMA-MAGA) particles were prepared by the dispersion polymerization in order to purify thrombin effectively. mPEGDMA-MAGA particles were synthesized by adding different ratios of magnetite (Fe₃O₄) to the medium in addition to the monomer phases EGDMA and MAGA. The characterization studies of mPEGDMA-MAGA particles were used by fourier transform infrared spectroscopy, zeta size measurement, scanning electron microscopy and electron spin resonance. mPEGDMA-MAGA particles were used in thrombin adsorption studies from aqueous thrombin solutions in both batch and magnetically stabilized fluidized bed (MSFB) system. Maximum adsorption capacity in pH 7.4 phosphate buffer solution is 964 IU/g polymer and 134 IU/g polymer in MSFB system and batch system, respectively. The developed magnetic affinity particles enabled the separation of thrombin from different patient serum samples in one step. It has also been observed that magnetic particles can be used repeatedly without significant reduction in adsorption capacity.

Self-assembled calcium pyrophosphate nanostructures for targeted molecular delivery

Nanostructured, inorganic microspheres have many industrial applications, including catalysis, electronics, and particularly drug delivery, with several advantages over their organic counterparts. However, many current production methods require high energy input, use of harmful chemicals, and extensive processing. Here, the self-assembly of calcium pyrophosphate into nanofibre microspheres is reported. This process takes place at ambient temperature, with no energy input, and only salt water as a by-product. The formation of these materials is examined, as is the formation of nanotubes when the system is agitated, from initial precipitate to crystallisation. A mechanism of formation is proposed, whereby the nanofibre intermediates are formed as the system moves from kinetically favoured spheres to thermodynamically stable plates, with a corresponding increase in aspect ratio. The functionality of the nanofibre microspheres as targeted enteric drug delivery vehicles is then demonstrated in vitro and in vivo, showing that the microspheres can pass through the stomach while protecting the activity of a model protein, then release their payload in intestinal conditions.

Porous Crystalsomes via Emulsion Crystallization and Polymer Phase Separation

Crystalsomes are crystalline capsules that are formed by controlling polymer crystallization to break translational symmetry. While recent studies showed that these crystalline capsules exhibit interesting mechanical properties, thermal behavior, and excellent performance in blood circulation, the closed capsule is undesired for drug delivery applications. We report the formation and characterization of porous crystalsomes where porosity is rendered on the crystalline shells. A miniemulsion is formed using two amphiphilic block copolymers (BCP). The competition between controlled crystallization and phase separation of the BCPs at the emulsion surface leads to multiphase crystalsomes. Subsequently removing one BCP produces porous crystalline capsules.

Rational Design of Pore Parameters in Monodisperse Porous Poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) Particles Based on Response Surface Methodology

Monodisperse porous poly(glycidyl methacrylate-co–ethylene glycol dimethacrylate) particles are widely applied in different fields, as their pore properties can be influenced and functionalization of the epoxy group is versatile. However, the adjustment of parameters which control morphology and pore properties such as pore volume, pore size and specific surface area is scarcely available. In this work, the effects of the process factors monomer:porogen ratio, GMA:EDMA ratio and composition of the porogen mixture on the response variables pore volume, pore size and specific surface area are investigated using a face centered central composite design. Non-linear effects of the process factors and second order interaction effects between them were identified. Despite the complex interplay of the process factors, targeted control of the pore properties was possible. For each response a response surface model was derived with high predictive power (all R2predicted > 0.85). All models were tested by four external validation experiments and their validity and predictive power was demonstrated.

Polymeric stationary phases for size exclusion chromatography: A review

Synthetic and natural macromolecules are commonly used in a variety of fields such as plastics, nanomedicine, biotherapeutics, drug delivery and tissue engineering. Characterising macromolecules in terms of their structural parameters (size, molar mass and distribution, architecture) is key to have a better understanding of their structure-property relationships. Size exclusion chromatography (SEC) is a commonly used technique for polymer characterization since it offers access to the determination of the size of a macromolecule, its molar mass and the molar mass distribution. Moreover, detectors that allow the determination of true molar masses, macromolecule's architecture and the composition of copolymers can be coupled to the chromatographic system. Like other chromatographic techniques, the stationary phase is of paramount importance for efficient SEC separations. This review presents the basic principles for the design of stationary phases for SEC as well as synthetic methods currently used in the field. Current status of fully-porous polymeric stationary phases used in SEC is reviewed and their advantages and limitations are also discussed. Finally, the potential of polymer monoliths in SEC is also covered, highlighting the limitations this column technology could address. However, further development in the polymer structure is needed to consider this column technology in the field of macromolecule separation.

Studies on Preparation, Characterization and Application of Porous Functionalized Glycidyl Methacrylate-Based Microspheres

A one-step swelling and polymerization technique was used in the synthesis of porous glycidyl methacrylate (GMA) and ethylene glycol dimethacrylate (EGDMA) monodisperse polymeric microspheres. The polystyrene (PS) seed obtained in the dispersion polymerization was used as a shape template. The presence of epoxide rings in the chemical structure of microspheres enables their post-polymerization chemical modifications involving: the Diels-Alder reaction with sodium cyclopentadienide and maleic anhydride, the reaction with 4,4′-(bismaleimido)diphenylmethane, and the thiol-Michael reaction with methacryloyl chloride and 2-mercaptopropionic acid. Changing the reaction mixture composition—the amounts of crosslinking monomer and PS seed as well as the type and concentration of porogen porous microspheres of different porous structures were obtained. Their porous structures were characterized in the dry and swollen states. The copolymers obtained from the equimolar monomers mixture modified in the above way were applied as the column packing materials and tested in the reverse-phase HPLC (High-Performance Liquid Chromatography). A few factors influencing morphology and porous structure of microspheres were studied.

Preparation of a hydroxypropyl-β-cyclodextrin functionalized monolithic column by one-pot sequential reaction and its application for capillary electrochromatographic enantiomer separation

In this study, a hydroxypropyl-β-cyclodextrin (HP-β-CD) functionalized monolithic capillary column was prepared by one-pot sequential reaction for the first time. The preparation of the HP-β-CD functionalized monolithic column involves two sequential reactions in one pot: (1) the ring opening reaction between HP-β-CD and glycidyl methacrylate (GMA) catalyzed by 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU); (2) the copolymerization of GMA-HP-β-CD, ethylene dimethacrylate (EDMA) and 2-acrylamido-2-methyl propane sulfonic acid (AMPS). A series of monolithic columns were successfully prepared by varying the temperature of the ring opening reaction or several copolymerization parameters (the type and composition of porogenic solvents, ratio of GMA-HP-β-CD to EDMA and polymerization temperature). Then, the morphologies and structures of the resulting monolithic stationary phases were characterized by optical microscopy, scanning electron microscopy (SEM) and nitrogen adsorption analysis. Raman spectroscopy clearly indicated the successful bonding of HP-β-CD onto the monolith. When the prepared chiral stationary phase (CSP) was applied for the separation of a set of racemic compounds by capillary electrochromatography (CEC), including racemic anticholinergic drugs, β-adrenergic drugs, meptazinol and its intermediates, satisfactory separation selectivities were obtained. Additionally, the column also showed excellent separation abilities towards four flavanone glycosides epimers. Furthermore, the prepared monolithic columns exhibited satisfactory stability and reproducibilities of retention time, resolution and column efficiency. These results demonstrated the potential and usefulness of the developed one-pot sequential strategy in the preparation of other derivatized CD functionalized monolithic columns.

Designing continuous flow reaction of xylan hydrolysis for xylooligosaccharides production in packed-bed reactors using xylanase immobilized on methacrylic polymer-based supports

The present study focuses on the development and optimization of a packed-bed reactor (PBR) for continuous production of xylooligosaccharides (XOS) from xylan. For this purpose, three different methacrylic polymer-based supports (Relizyme R403/S, Purolite P8204F and Purolite P8215F) activated with glyoxyl groups were morphologically characterized and screened for the multipoint covalent immobilization of a xylanase. Based on its physical and mechanical properties, maximum protein loading and thermal stability, Relizyme R403/S was selected to set up a PRB for continuous production of XOS from corncob xylan. The specific productivity for XOS at 10 mL/min flow rate was 3277 g_XOS g_enzyme^-1 h^-1 with a PBR. This PBR conserved >90% of its initial activity after 120 h of continuous operation.

Current status and future developments in preparation and application of nonspherical polymer particles

Nonspherical polymer particles (NPPs) are nano/micro-particulates of macromolecules that are anisotropic in shape, and can be designed anisotropic in chemistry. Due to shape and surface anisotropies, NPPs bear many unique structures and fascinating properties which are distinctly different from those of spherical polymer particles (SPPs). In recent years, the research on NPPs has surprisingly blossomed in recent years, and many practical materials based on NPPs with potential applications in photonic device, material science and biomedical engineering have been generated. In this review, we give a systematic, balanced and comprehensive summary of the main aspects of NPPs related to their preparation and application, and propose perspectives for the future developments of NPPs.

A facile route to bespoke macro- and mesoporous block copolymer microparticles

A facile and versatile strategy to fabricate macro- and mesoporous block copolymer microparticles with bespoke characteristics using supercritical CO₂.

Morphological Properties of Methacrylate-Based Polymer Monoliths: From Gel Porosity to Macroscopic Inhomogeneities

Shaping chemical interfaces of hard and soft matter materials into physical morphologies that guarantee excellent transport properties is of central importance for technologies relying on adsorption, separation, and reaction at the interface. Polymer monoliths with a hierarchically structured pore space, for example, are widely used in flow-driven processes, whose efficiency depends on the morphology of the support material over several length scales. Compared with alternative support structures, particularly silica monoliths, polymer monoliths yield lower efficiency, which suggests a suboptimal morphology. Based on physical reconstruction by serial block-face scanning electron microscopy we evaluate the structural features of a methacrylate-based polymer monolith from the pore scale to the column scale. The morphological data reveal a homogeneous polymer skeleton with a solute-impenetrable core-porous shell architecture and a heterogeneous macropore space that suffers from inhomogeneities at the short-range and the transcolumn scale. Although the morphology of the polymer phase is favorable to efficient mass transport, the performance of the polymer monolith is limited by severe transcolumn gradients in macroporosity and macropore size. We propose to overcome these morphological limitations by pursuing a preparation strategy that involves active rather than passive shaping of the macropore space, for example, by using silica monoliths as templating structures for polymer monolith preparation.

Strong Microcapsules with Permeable Porous Shells Made through Phase Separation in Double Emulsions

Microcapsules for controlled chemical release and uptake are important in many industrial applications but are often difficult to produce with the desired combination of high mechanical strength and high shell permeability. Using water-oil-water double emulsions made in microfluidic devices as templates, we developed a processing route to obtain mechanically robust microcapsules exhibiting a porous shell structure with controlled permeability. The porous shell consists of a network of interconnected polymer particles that are formed upon phase separation within the oil phase of the double emulsion. Porosity is generated by an inert diluent incorporated in the oil phase. The use of undecanol and butanol as inert diluents allows for the preparation of microcapsules covering a wide range of shell-porosity and force-at-break values. We found that the amount and chemical nature of the diluent influence the shell porous structure by changing the mechanism of phase separation that occurs during polymerization. In a proof-of-concept experiment, we demonstrate that the mechanically robust microcapsules prepared through this simple approach can be utilized for the on-demand release of small molecules using a pH change as exemplary chemical trigger.

Synthesis of well-defined epoxy-functional spherical nanoparticles by RAFT aqueous emulsion polymerization

The environmentally-friendly synthesis of epoxy-functional spherical nanoparticles is achieved via RAFT aqueous emulsion polymerization of glycidyl methacrylate under mild conditions; derivatization of such nanoparticles with sodium azide or diamines is demonstrated.

Macroporous materials: microfluidic fabrication, functionalization and applications

This article provides an up-to-date highly comprehensive overview (594 references) on the state of the art of the synthesis and design of macroporous materials using microfluidics and their applications in different fields.

One-pot preparation of poly(styrene-co-divinylbenzene)/silver nanoparticles composite microspheres with tunable porosity and their catalytic degradation of methylene blue in aqueous solution

Porous poly(styrene-co-divinylbenzene)/silver nanoparticle composite spheres with tunable porosity were synthesized by seed swelling polymerization method and show a great catalytic degradation of methylene blue within NaBH₄.

High porosity microspheres with functional groups synthesized by thiol–yne click suspension polymerization

We employed a combination of thiol–yne click polymerization and suspension polymerization for the synthesis of porous epoxy-functionalized polymeric microspheres.

Molecularly imprinted microspheres prepared by precipitation polymerization at high monomer concentrations

Highly crosslinked polymer microparticles have been prepared by precipitation polymerization using high monomer loadings (≥25 v/v %) which generally would lead to bulk monoliths. The microparticle format was achieved by the use of non-solvating diluents either alone or in combination with co-solvents. Two distinct morphologies were observed. Monodisperse smooth microspheres were obtained using a thermodynamically good co-solvent whereas segmented irregular particles were formed with poorer co-solvents. It has been found that during polymerization the forming polymer particles were enriched in the co-solvent and this effect was more pronounced when good co-solvents were used. The type of functional monomer, crosslinker and co-solvent, and the non-solvent/co-solvent ratio were identified as influential parameters on the microparticle morphology. With the proposed methodology molecularly imprinted microparticles have been prepared successfully for three different templates, naproxen, diclofenac and toltrazuril using various functional monomers, crosslinkers and polymerization solvent mixtures.