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2022

Endotoxins are robust and persistent impurity, which are native to majority of phage substrates. Two anion exchangers, CIMmultus PrimaS and H-Bond, were tested for their capacity for endotoxin removal in comparison to well known strong anion exchanger, CIMmultus QA. 

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2019

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.

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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.

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2014

In recent years bacteriophages were identified as a useful potential tool for different applications such as alternative to antibiotics, detection of pathogenic bacteria, delivery vehicles for protein and DNA vaccines and as gene therapy delivery vehicles. For all listed fields of use it is important that phages are highly purified with preserved biological activity. Phage and other virus purification have traditionally been carried out by CsCl2 density gradient ultracentrifugation, which is however difficult to be scaled-up. An alternative is chromatography, which already proved to be efficient for separation and purification of certain virus types. Methacrylate monoliths (CIM Convective Interaction Media® monolithic columns) were designed for purification of bionanoparticles and they already proved to be very efficient for concentration and purification of several plant and human viruses (influenza A, influenza B, adenovirus type 5, hepatitis A and others).

Our aim was to investigate whether CIM methacrylate monolithic columns can be implemented for purification of phages. Staphylococcus aureus phage VDX-10 was selected. Chromatographic support chemistry and buffer screening led to development of purification method on strong anion exchanger. Optimised single step purification method developed for S. aureus VDX-10 phage on CIM® QA monolithic column resulted in efficient removal of host cell DNA and proteins with high recovery of viable phage.

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2009

Bacteriophages were in recent years identified as a useful potential tool for different biotechnological applications such as alternative to antibiotics, detection of pathogenic bacteria, delivery vehicles for protein and DNA vaccines and as gene therapy delivery vehicles (1). For all listed fields of use it is important that phages are highly purified with preserved biological activity. Phage and other virus purification have traditionally been carried out by CsCl density gradient ultracentrifugation, which is however difficult to be scaled-up. An alternative is chromatography already proved to be efficient for purification and concentration of certain virus types.

One of the key issues using chromatography is processing time and capacity of the resin. Novel type of chromatographic resin named monoliths was already proved to be very efficient for fast separation and purification of macromolecules as are large proteins, DNA and viruses (2,3,4).

Our aim was to investigate whether Convective Interaction Media (CIM) methacrylate monolithic columns can be implemented for purification and concentration of phage T4 (virus for E.coli). Chromatographic method using linear gradient was implemented to investigate conditions for phage elution and to establish the optimized chromatographic method applying step gradient. We analyzed phage recovery and purity together with method reproducibility.

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2005

The rapidly growing interest in the area of proteomics induces intensive efforts to find robust, automated and sensitive high-throughput analytical tools. In this context, the concept of solid-phase digestion (ex. trypsin immobilization on a solid support[1]) has received great attention in the last years. Trypsin (EC 3.4.21.4) has been covalently immobilized on different monolithic supports and resulting bioreactors used as immobilized enzyme reactors (IMERs) for on-line digestion, peptide separation and peptide mapping. Bioreactors efficiencies were evaluated with different recombinant proteins after on-line digestion. The technique used for the separation and identification of peptides was high-performance liquid chromatography coupled with electrospray ionisation tandem mass spectrometry (LC-ESI-MS/MS).

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2003

The only four drugs approved for the clinical treatment of Alzheirner’s Disease (tacrine. rivastigmine, donepezil and galantamine) are acetylcholinesterase inhibitors which act by maintaining high levels of acetylcholine at the muscarinic and nicotinic receptors in the central nervous system. Human acetylcholinesterase (HuAChE) represents a widely studied target enzyme and it is still object of research for the development of new drugs as enzyme inhibitors.

In a previous paper we reported the immobilisation of AChE on a silica based chromatographic column (50 x 4.6 mm 1.0.) The yeld of immobilization and the stability of the AChE-IMER were considered satisfactory, but some problems arose. The length of the IMER and the large amount of enzyme covalently bound to the chromatographic support resulted in catalysis product long elution times and some inhibitors aspecific matrix absorption with delayed enzyme activity recovery. In order to avoid these complications and considering the high rate of AChE enzymatic reaction. we decided to reduce the dimension of the solid support for immobilization, hence the amount of immobilized enzyme, by selecting a monolithic matrix disk (12 x 3 mm I.D.).

CIM® (Convective Interaction Media) monolithic supports (Biaseparations. Lubiana) represent a novel generation of stationary phases used for liquid chromatography, bioconversions, and solid phase synthesis. As opposed to individual particles packed into chromatographic columns, CIM® supports are cast as continuous homogeneous phases and provide high rates of mass transfer at lower back pressure.

In the present work a CIMK disk with immobilised human recombinant acetylcholinesterase (HuAChE-ClM® Disk) was developed. The activity of immohilised enzyme, the long term stability and reproducibility were tested. HuAChE-CIM® disk was applied as an immobilised enzyme micro-reactor (micro-IMER) in on-line HPLC system for inhibitory potency determination of known AChE inhibitors.

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