Posters

One of the handicaps of working with bacteriophages is the long duration required to perform plaque assays. Plaque assays also impose questions about accuracy and precision relative to the scale and experience of the persons performing and interpreting them. This poster presents a pair of high precision, high accuracy chromatography-based assays that permit determination of phage concentration in less than 1 hour. Sensitivity of UV absorbance is poor because of the low concentration of phages. However, phage sensitivity is strongly amplified by monitoring the chromatogram with either fluorescence or MALS. Fluorescence works by measuring the fluorescence emission from tryptophan residues of the phage proteins. MALS works by passing a laser beam through the sample and reading the scatter produced when it encounters a particle. Larger species generate more scatter.

Bacteriophages represent immense potential as therapeutic agents. Many of the most compelling applications of bacteriophages involve human therapy, some pertinent to gene therapy, others involving antibiotic replacement. In bacteriophage research and therapy, most applications ask for highly purified phage suspensions, as such it is crucial to reduce proteins, endotoxins, DNA and other contaminants. The most common technique for purification is ultracentrifugation using cesium chloride gradients. This technique is elaborate, cumbersome, expensive and difficult to scale-up.
Alternative techniques for purification are usually time consuming and affect phage recovery and/or viability. In this study we present efficient two-step chromatographic purification method with binding phages to a stationary phase - Convective Interaction Media (CIM®) monoliths. The aim of the study was to develop robust, fast and effective virus purification platform that can be used for several types of bacteriophages for any application. In this work bacterial lysate with bacteriophage T4 (host E.Coli) was used.

Immunoaffinity columns using antibodies as ligands against mammalian proteins could be used for different applications in protein expression control and, if a standard available, for direct protein quantification in complex sample solutions. Additionally, these columns are ideal for polishing step of recombinant proteins, such as mammalian receptor Fc fusion proteins. Most importantly, such columns could extract a significant amount of a single membrane protein from native source, suitable for downstream analyses, such as mass spec analysis of their glycans. Immunoaffinity chromatographic monoliths against RAE-1 GPI anchored glycoprotein were developed (CIMmic HDZ - @RAE-1 column) as a part of Glycomet project with the main goal to analyze the antigen glycoprofile.

Hydrazide-activated (HDZ) columns were proven to be a product of choice for making the most effective immunoaffinity columns. They take advantage of a special hydrazide linkage that binds antibodies through the carbohydrate residues on their Fc regions. This leaves the antigen-binding domains fully accessible to enable the most effective capture of desired target (Figure bellow).
CIMac™ HDZ monoliths make HDZ-immobilized antibody columns even more effective. Because of their large channel size and the efficiency of convective mass transport, they eliminate the long loading residence times that are required for affinity chromatography on porous particle columns. Flow rates of 5–10 column volumes per minute allow complete purifications in a few minutes, even when the source material contains a low concentration of antigen. The same performance is achieved whether a small peptide or a large bio-assemblage like a virus particle or extracellular vesicle is isolated. The combination of HDZ monoliths and the immobilization protocol offers a strong tool for fast antigen isolation from complex biological sample (plasma, lysate, etc.) and consequently sensitive antigen quantification. An example of CIMac™ HDZ application is a purification of fibrinogen from human plasma.

CIM® chromatographic monoliths enable high 1) productivity of pDNA downstream process (DSP) due to high dynamic binding capacity for pDNA in small elution volumes and short chromatographic runs; 2) high resolution power due to convective-based mass transfer.

Sample displacement mode utilizes different relative binding affinities of components in a sample mixture and separates pDNA isoforms under overloading conditions - where sc pDNA isoform acts as a displacer of oc or linear pDNA isoform.

Production of high value biological therapeutics usually involves complex manufacturing processes with high process variability. Additionally, development of robust and reliable bioprocesses can be challenging. PAT aims to enhance bioprocess understanding and implies a holistic approach to ensure that quality is built into products by design. Efficient PAT therefore calls for fast and robust analytical techniques which enables to asses high quality information about critical quality attributes and key performance indicators as parallel as possible to the manufacturing process. PATfix™ is unique analytical system for routine gradient separations that enables every analytical task. Equipped with bio-inert ceramic pump heads is deliberately tailored to meet the demands of analytical applications covering wide range of biomolecules. Highly sensitive and fast multi-wavelength detector enables to detect component peaks even in very fast gradients.

Preparative scale chromatographic separation of open-circular (oc) from supercoiled (sc) plasmid DNA (pDNA) isoforms has been already established on CIM® C4 with high ligand density (C4 HLD) monolithic columns with sample loading in 3.0 M ammonium sulphate (AS). The process requires high molarity of AS, increasing the overall cost of the process. Sample displacement chromatography (SDC) can be used as an alternative to decrease the AS concentration required during loading onto hydrophobic chromatographic supports. This study compares three chromatographic monoliths with different hydrophobic ligands on the surface (C4 HLD, pyridine and histamine) for the purification of different pDNA vectors in SD mode.

Productivity of the downstream bioprocessing depends among others on the efficiency of chromatographic step. One of the crucial chromatographic parameters is dynamic binding capacity (DBC) for certain biomolecule. DBC could be tailored with changing the surface area of convective pores by tailoring the surface of pre-polymerized monoliths using graft or block polymerization of polymer brushes. Grafted CIM monoliths have already been prepared via Radical Polymerization (RP) and successfully characterized (1).

Recently, the implementation and optimization of Controlled Radical Polymerization (CRP) for grafting of large pore monoliths (average diameter 6 μm ) resulted in polymethacrylate-based ionic exchanger with at least 5 times higher DBC compared to non-grafted 6 μm monoliths, while preserving high permeability. The main goal of our study was to chromatographically characterize novel grafted ion-exchanging monoliths (CIM gDEAE and CIM gSO3) to see whether novel columns still retain flow independent chromatographic properties of non-grafted monoliths.

The upstream and downstream monoclonal antibody (mAb) bioprocessing makes them susceptible to physical and chemical modifications. In the biotechnological production process of mAbs, structural variations may arise due to some enzymatic activity. Antibody charge variants have gained considerable attention in the biotechnology industry due to their potential influence on stability and biological activity and cation-exchange chromatography (CEX) is one of the typical approaches for mAb charge variant analyses. We tested several CEX columns under different conditions and the best column for isotype separation was weak cation-exchanging CIMac COOH chromatographic monolith in pH gradient. We have proven a flow independent separation of mAb charge variants and in this way, a resolution comparable to classical CEX particulate-based analytical columns was achieved in only 6 min analysis time.

To ensure the desired chromatographic characteristics of the CIM® monolithic column at large scales, monolith microstructure morphology, pore size distribution, porosity and surface ligand density should be uniform. To demonstrate the uniformity of large chromatographic monoliths we have developed new testing procedures. By fabricating smaller columns (disks) from different random  positions of larger monolith, non-cGMP compliant chromatographic testing can be applied on the same polymerization batch without affecting the cGMP compliance of large-scale chromatographic monolith. Each individual disk was thoroughly tested and the results were compared to the properties of the large monolith.

Since plasmid DNA (pDNA) as a pharmaceutical product has stringent requirements of purity and efficacy, one or more chromatographic steps are often used in the downstream processing train. High ligand density butyl-modified (C4 HLD) monolithic support is currently used in a polishing step of a pDNA purification process (1) and is mainly focused to supercoiled (sc) pDNA isoform separation from the open circular (oc) and linear pDNA isoform as well as for removal of remaining gDNA and RNA. The goal of the study was to compare the productivities of two variations of the polishing chromatographic process employing monoliths – classical bind-elute (BE) versus recently described (2) sample displacement purification (SDP). Classical purification requires high concentration of ammonium sulphate (AS) during loading step and elution is then achieved by descending AS gradient. SDP utilises different relative binding affinities of components in a sample mixture and separates pDNA isoforms under overloading conditions, where sc pDNA isoform acts as a displacer of oc or linear pDNA isoform.

There are many cases, where a single protein needs to be purified from a complex sample. Such proteins manifest themselves as impurities, which can affect further analysis, either by causing specific equipment malfunction or lower yield in the products. In other cases the specific protein is our molecule of interest, for example in glycomics analysis. In both cases high specificity for proteins, reproducibility and reliability is necessary. We have developed a model immunoaffinity column and 96-well plate based on an anti-fibrinogen monoclonal antibody, covalently immobilized onto CIMac™ analytical chromatographic monolith.

There are many cases, where a single protein needs to be purified from a complex sample. Such proteins manifest themselves as impurities, which can affect further analysis, either by causing specific equipment malfunction or lower yield in the products. In other cases the specific protein is our molecule of interest, for example in glycomics analysis. In both cases high specificity for proteins, reproducibility and reliability is necessary. We have developed a model immunoaffinity column and 96-well plate based on an anti-fibrinogen monoclonal antibody, covalently immobilized onto CIMac™ HDZ analytical chromatographic monolith.

Methacrylate monoliths (CIM® monolithic columns) allow for very fast and efficient separations and exhibit very high binding capacities for extremely large bio-particles due to their large inner channel diameters and enhanced mass transfer characteristics.
Additionally, the ability to manufacture polymer monolithic materials ranging from analytical to large scale preparative/industrial columns has tremendous advantages. By ensuring the chromatographic properties are consistent over the whole size range, one can easily design and optimize a purification method on laboratory scale and transfer it to a production line with minimal to no additional modifications.

Until now the largest monolithic column had a volume of 8 L, which was large enough to serve the biopharmaceutics' market's needs. Now however, the capacity of that column is already at its upper limit.

By successfully employing the knowledge and experience from almost two decades of monolith production we have managed to overcome the size limitations and polymerize the largest convective chromatographic support made from one piece of material, a 40 L monolithic column.

CIMac™ r-Protein A Analytical Column is short bed, high performance monolithic column . Primarly is intended for fast, efficient, and reproducible qualitative and quantitative analyses of Immunoglobulin G (IgG). It is suitable for use with HPLC and UPLC systems. Quantification of Immunoglobulin G is possible between 0.2 μg and 20 μg. Its small volume and short column length allow operation at high volumetric flow rates ( up to 3mL/min). The information about product quantity and purity is thus generated in just 1 minute! The column has innovative symmetric design for bi-directional flow, also extending column lifetime.

Immunoaffinity columns using antibodies as ligands against mammalian membrane proteins could be used for different applications in protein expresion control and, if a standard available, for concentration determination. Additionally these columns are ideal for polishing step of Fc fusion proteins of mammalian receptors.

Most importantly such columns could extract a significant amount of a pure membrane mammalian protein suitable for structural analyses, such as mass spec analysis of their glycans. Immunoaffinity chromatographic monoliths against MULT-1 transmembrane and RAE-1 GPI anchored glycoproteins were developed as a part of Glycomet project with the main goal to analyze the antigen glycan parts.

Two different  preactivated support were used:  hydrazide (HDZ) and carboxy imidazole (CDI).

Biological samples often consist of a main component, such as albumin in serum, and many other constituents, present in smaller quantities, but nevertheless of high importance in biological systems. When detection of the low-abundance molecules is needed, the main component could interfere with the analyte, complicating the analysis or even making it impossible. In such cases a possible approach is to remove the interfering main component from the sample before the analysis.

Monolithic columns (CIM®) are a great foundation to build affinity chromatography methods, as they offer fast flow rates and can be modified to accomodate various ligands. We selected two most promising approaches for oriented binding of antibodies to the monolithic support. One approach was to bind antibodies to a protein A (pA) column with consequent crosslinking of the protein complex. The other approach was to chemically activate antibodies and bind them selectively to hydrazide-modified (HDZ) monolith surface.

Surface hydrophobicity/hydrophilicity of chromatographic stationary phases is one of the important characteristics that influence the chromatographic column performance. On the one hand, the surface should be highly hydrophilic to avoid nonspecific adsorption of sample molecules; on the other hand, the hydrophobic surface is crutial to e.g. separate the molecule isoforms.Therefore, fast and easy characterization method to evaluate the surface „hydrophobic/hydrophilic character" could be valuable.

First stage in the development of this method and the objective of this study was to evaluate the hydrophobicity of test set of 1 mL CIM columns with different ligand chemistries and densities. This was achieved by separation of protein mixture under hydrophobic interaction chromatography (HIC) conditions. Proteins were used since monoliths are used mainly in downstream of large biomolecules.

Moreover, since poor recovery under HIC conditions was observed on some columns, the research was additionally expanded with reversed phase chromatography (RPC) to obtain extra information about even more hydrophobic surface properties of monolithic columns. Therefore, after HIC step the RPC step followed and additional elution of proteins was achieved.

Exosomes are nano-sized vesicles that are released by many different cell types. They are involved in the transport of a wide range of signalling molecules, including mRNA, microRNA and proteins. Exosomes have been found into body fluids and multiple roles have been ascribed to exosomes, in particular in cell signalling where it has been demonstrated their correlation to disease progression and their overexpression as specific tumour cell biomarkers, suggesting their important role in their diagnosis.

This initial screening oriented towards the separation of exosomes from a cell culture supernatant, has been developed by BIA Separations in collaboration with Exosomics Siena. Exosomes used for this study were cultivated in two different cell lines, MeWo and LNCap, and, after the harvesting, a relatively pure target molecule was obtained after several centrifugations, filtrations and batch affinity capture step with a commercial purification kit. In order to speed-up the process and bring current DSP on a higher level, a novel purification approach based on chromatography, using CIM® monolithic columns was investigated. Monolithic supports represent a new generation of chromatographic media. Due to their large inner channel diameters and enhanced mass transfer characteristics, methacrylate monoliths offer efficient and fast separation of large biomolecules like vescicles, pDNA, viruses and monoclonal antibodies. High binding capacity, good product recovery and resolution are also benefits of monoliths. Different samples, (Standard batch purified exosomes, Culture supernatant filtered, Culture supernatant non-filtered), derived from MeWo and LNCap culture media,, were screened. QA, SO3, DEAE and OH CIM 1mL tube - 6μm pore size were screened. CIM® QA - 6μm pores was chosen.

One of the major requirements for pharmaceutical-grade pDNA is its high homogeneity, being mostly in supercoiled (sc) isoform. Chromatographic separation of sc pDNA from open coiled (oc) or linear isoform is challenging due to their similar interactions with the chromatographic phases. Promising separation efficiency of pDNA isoforms was proven on recently developed histamine modified monolithic chromatographic column in descending ammonium sulfate gradient. The aim of the study was to further optimise the chromatographic conditions for sample analysis, where all three isoforms would be baseline separated.