Affinity processes realized on high-flow-through methacrylate-based macroporous monoliths

Preparation of Affinity Chromatography Monolith in Miniaturized Format and Application for Protein Separation

Affinity chromatography is one of the versatile technique to selectively separate target biomolecules from complex biological sources (plasma, saliva, urine, etc.). Conventional chromatography resins possess technical limitations at mini-analytical scale, which was overcome with the use of alternative material known as monoliths. This chapter discusses on the how to modify the fused silica capillary inner surface, prepare polymer monoliths within the capillary confinements, chelation of metal-ions on monoliths and protein separation from diluted human plasma using metal-ion monolith microcolumn.

Affinity monolith chromatography: A review of general principles and recent developments

Affinity monolith chromatography (AMC) is a liquid chromatographic technique that utilizes a monolithic support with a biological ligand or related binding agent to isolate, enrich, or detect a target analyte in a complex matrix. The target-specific interaction exhibited by the binding agents makes AMC attractive for the separation or detection of a wide range of compounds. This article will review the basic principles of AMC and recent developments in this field. The supports used in AMC will be discussed, including organic, inorganic, hybrid, carbohydrate, and cryogel monoliths. Schemes for attaching binding agents to these monoliths will be examined as well, such as covalent immobilization, biospecific adsorption, entrapment, molecular imprinting, and coordination methods. An overview will then be given of binding agents that have recently been used in AMC, along with their applications. These applications will include bioaffinity chromatography, immunoaffinity chromatography, immobilized metal-ion affinity chromatography, and dye-ligand or biomimetic affinity chromatography. The use of AMC in chiral separations and biointeraction studies will also be discussed.

Investigating Monoliths (Vinyl Azlactone-co-Ethylene Dimethacrylate) as a Support for Enzymes and Drugs, for Proteomics and Drug-Target Studies

Prior to mass spectrometry, on-line sample preparation can be beneficial to reduce manual steps, increase speed, and enable analysis of limited sample amounts. For example, bottom-up proteomics sample preparation and analysis can be accelerated by digesting proteins to peptides in an on-line enzyme reactor. We here focus on low-backpressure 100 μm inner diameter (ID) × 160 mm, 180 μm ID × 110 mm or 250 μm ID × 140 mm vinyl azlactone-co-ethylene dimethacrylate [poly(VDM-co-EDMA)] monoliths as supports for immobilizing of additional molecules (i.e., proteases or drugs), as the monolith was expected to have few unspecific interactions. For on-line protein digestion, monolith supports immobilized with trypsin enzyme were found to be suited, featuring the expected characteristics of the material, i.e., low backpressure and low carry-over. Serving as a functionalized sample loop, the monolith units were very simple to connect on-line with liquid chromatography. However, for on-line target deconvolution, the monolithic support immobilized with a Wnt pathway inhibitor was associated with numerous secondary interactions when exploring the possibility of selectively trapping target proteins by drug-target interactions. Our initial observations suggest that (poly(VDM-co-EDMA)) monoliths are promising for e.g., on-line bottom-up proteomics, but not a "fit-for-all" material. We also discuss issues related to the repeatability of monolith-preparations.

Monoliths in capillary electrochromatography and capillary liquid chromatography in conjunction with mass spectrometry

Here, we have reviewed separation studies utilizing monolithic capillary columns for separation of compounds preceding MS analysis. The review is divided in two parts according to the used separation method, namely CEC and capillary LC (cLC). Based on our overview, monolithic CEC-MS technique have been more focused on the syntheses of highly specialized and selective separation phase materials for fast and efficient separation of specific types of analytes. In contrast, monolithic cLC-MS is more widely used and is often employed, for instance, in the analysis of oligonucleotides, metabolites, and peptides and proteins in proteomic studies. While poly(styrene-divinylbenzene)-based and silica-based monolithic capillaries found their place in proteomic analyses, the other laboratory-synthesized monoliths still wait for their wider utilization in routine analyses. The development of new monolithic materials will most likely continue due to the demand of more efficient and rapid separation of increasingly complex samples.

Affinity chromatography of proteins on monolithic columns

At present, monolithic stationary phases, because of their morphology, are widely used for development and realization of fast dynamic and static processes based on mass transition between liquid and solid phases. These are liquid chromatography, solid phase synthesis, microarrays, flow-through enzyme reactors, etc. High-performance liquid chromatography on monoliths, including bioaffinity mode, represents a unique technique appropriate for fast and efficient separation of biological (macro)molecules of different sizes and shapes (proteins, nucleic acids, peptides), as well as such supramolecular systems as viruses.In this work, the examples of application of commercially available macroporous monoliths for modern affinity processing are presented. In particular, the original methods developed for efficient isolation and fractionation of monospecific antibodies from rabbit blood sera, the possibility of simultaneous affinity separation of protein G and serum albumin from human serum, the isolation of recombinant products, such as protein G and tissue plasminogen activator from E. coli cell lysate and Chinese Hamster Ovary cell culture supernatant, respectively, are described in detail. The suggested and realized multifunctional fractionation of polyclonal pools of antibodies by combination of several short monolithic columns (disks) with different affinity functionalities stacked in the same cartridge represents an original and practically valuable method that can be used in biotechnology.

Macroporous methacrylate-based monoliths as platforms for DNA microarrays

Macroporous monoliths with different surface functionalization (reactive groups) were utilized as platforms for DNA analysis in microarray format. The slides based on a copolymer glycidyl methacrylate-co-ethylene dimethacrylate (GMA-EDMA) have been chosen as well known and thoroughly studied standard. In particular, this material has been used at optimization of DNA microanalytical procedure. The concentration and pH of spotting solution, immobilization temperature and time, blocking agent and coupling reaction duration were selected as varied parameters. The efficiency of analysis performed on 3-D monolithic platforms was compared to that established for commercially available glass slides. As a practical example, a diagnostic test for detection of CFTR gene mutation was carried out. Additionally, the part of presented work was devoted to preparation of aptamer-based test-system that allowed successful and highly sensitive detection both of DNA and protein.

Bioaffinity chromatography on monolithic supports

Affinity chromatography on monolithic supports is a powerful analytical chemical platform because it allows for fast analyses, small sample volumes, strong enrichment of trace biomarkers and applications in microchips. In this review, the recent research using monolithic materials in the field of bioaffinity chromatography (including immunochromatography) is summarized and discussed. After giving an introduction into affinity chromatography, information on different biomolecules (antibodies, enzymes, lectins, aptamers) that can act as ligands in bioaffinity chromatography is presented. Subsequently, the history of monoliths, their advantages, preparation and formats (disks, capillaries and microchips) as well as ligand immobilization techniques are mentioned. Finally, analytical and preparative applications of bioaffinity chromatography on monoliths are presented. During the last four years 37 papers appeared. Protein A and G are still most often used as ligands for the enrichment of immunoglobulins. Antibodies and lectins remain popular for the analysis of mainly smaller molecules and saccharides, respectively. The highly porous cryogels modified with ligands are applied for the sorting of different cells or bacteria. New is the application of aptamers and phages as ligands on monoliths. Convective interaction media (epoxy CIM disks) are currently the most used format in monolithic bioaffinity chromatography.

Applications of polymethacrylate-based monoliths in high-performance liquid chromatography

Monolithic columns were introduced in the early 1990s and have become increasingly popular as efficient stationary phases for most of the important chromatographic separation modes. Monoliths are functionally distinct from porous particle-based media in their reliance on convective mass transport. This makes resolution and capacity independent of flow rate. Monoliths also lack a void volume. This eliminates eddy dispersion and permits high-resolution separations with extremely short flow paths. The analytical value of these features is the subject of recent reviews. Nowadays, among other types of rigid macroporous monoliths, the polymethacrylate-based materials are the largest and most examined class of these sorbents. In this review, the applications of polymethacrylate-based monolithic columns are summarized for the separation, purification and analysis of low and high molecular mass compounds in the different HPLC formats, including micro- and large-scale HPLC modes.

Development of an affinity silica monolith containing human serum albumin for chiral separations

An affinity monolith based on silica and containing immobilized human serum albumin (HSA) was developed and evaluated in terms of its binding, efficiency and selectivity in chiral separations. The results were compared with data obtained for the same protein when used as a chiral stationary phase with HPLC-grade silica particles or a monolith based on a copolymer of glycidyl methacrylate (GMA) and ethylene dimethacrylate (EDMA). The surface coverage of HSA in the silica monolith was similar to values obtained with silica particles and a GMA/EDMA monolith. However, the higher surface area of the silica monolith gave a material that contained 1.3-2.2-times more immobilized HSA per unit volume when compared to silica particles or a GMA/EDMA monolith. The retention, efficiency and resolving power of the HSA silica monolith were evaluated using two chiral analytes: d/l-tryptophan and R/S-warfarin. The separation of R- and S-ibuprofen was also considered. The HSA silica monolith gave higher retention and higher or comparable resolution and efficiency when compared with HSA columns that contained silica particles or a GMA/EDMA monolith. The silica monolith also gave lower back pressures and separation impedances than these other materials. It was concluded that silica monoliths can be valuable alternatives to silica particles or GMA/EDMA monoliths when used with immobilized HSA as a chiral stationary phase.

Development of an affinity silica monolith containing alpha1-acid glycoprotein for chiral separations

An affinity monolith based on silica and containing immobilized alpha(1)-acid glycoprotein (AGP) was developed and evaluated in terms of its binding, efficiency and selectivity in chiral separations. The results were compared with data obtained for the same protein when used as a chiral stationary phase with HPLC-grade silica particles or monoliths based on a copolymer of glycidyl methacrylate (GMA) and ethylene dimethacrylate (EDMA). The surface coverage of AGP in the silica monolith was 18% higher than that obtained with silica particles and 61% higher than that measured for a GMA/EDMA monolith. The higher surface area of the silica monolith gave materials that contained 1.5- to 3.6-times more immobilized protein per unit volume when compared to silica particles or a GMA/EDMA monolith. The retention, efficiency and resolving power of the AGP silica monolith were evaluated by injecting two chiral analytes onto this column (i.e., R/S-warfarin and R/S-propranolol). In each case, the AGP silica monolith gave higher retention plus better resolution and efficiency than AGP columns containing silica particles or a GMA/EDMA monolith. The AGP silica monolith also gave lower back pressures and separation impedances than these other materials. It was concluded that silica monoliths can be valuable alternatives to silica particles or GMA/EDMA monoliths when used with AGP as a chiral stationary phase.

Preparation of a monolithic column for weak cation exchange chromatography and its application in the separation of biopolymers

A procedure for the preparation of a monolithic column for weak cation exchange chromatography was presented. The structure of the monolithic column was evaluated by mercury intrusion. The hydrodynamic and chromatographic properties of the monolithic column--such as back pressures at different flow rates, effects of pH on protein retention, dynamic loading capacity, recovery, and stability--were determined under conditions typical for ion-exchange chromatography. The prepared monolithic column might be used in a relatively broad pH range from 4.0 to 12.0 and exhibited an excellent separation to five proteins at the flow rates of both 1.0 and 8.0 mL/min, respectively. In addition, the prepared column was first used in the purification and simultaneous renaturation of recombinant human interferon gamma (rhIFN-gamma) in the extract solution with 7.0 mol/L guanidine hydrochloride. The purity and specific bioactivity of the purified rhIFN-gamma in only one chromatographic step were obtained to be 93% and 7.8 x 10(7) IU/mg, respectively.