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2005

Viruses have proven to be useful vectors for gene therapy purposes. As therapeutics for human use they must be pure and contaminant free. Traditionally, viruses are purified by complicated and time consuming methods such as CsCl density gradient centrifugation or similar. In recent years liquid chromatography has became interesting method for virus purification. It provides high level of purity required for human use and increases productivity. Traditional chromatographic supports were mostly designed for purification of proteins and as such are commonly inappropriate for viruses. Alternative to traditional chromatographic support are methacrylate monoliths (CIM monoliths), characterized by large channel diameter, high surface accessibility and convective mass transport.

The aim of this work was to characterize CIM supports for separation and possible purification of a model virus Tomato mosaic virus (ToMV) from crude plant material.

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2004

Traditionally, viruses are purified by time consuming methods such as CsCl density gradient centrifugation or similar. These methods are often inefficient and limited to small scale. In recent years different methods for virus purification, based on ion exchange, gel filtration and affinity chromatography have became popular. Recently, CIM® disk monolithic columns were used for successful concentration of two plant viruses (1) and for improved detection of two human viruses (2). Cucumber mosaic virus (CMV) and Tomato mosaic virus (ToMV) were concentrated and subsequently detected from extremely diluted samples in which they were initially undetectable. Successful concentrations of both viruses encourage us to explore the possibilities of CIM® supports for virus purification. As a model virus ToMV was selected. ToMV is a rod shaped plant virus with a typical size of 300 x 18 nm and isoelectric point at pH 4.6.

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The availability of sufficient quantities of quality DNA is always a crucial point in DNA based methods, i.e. for PCR, DNA sequencing, Southern blotting, and microarrays [1]. The same is true for the PCR-based methods for detection of genetically modified food [2]. During the production chain foods passes several physical, biological, and chemical processes, which all negatively influences on the quantity of available DNA. The phenomenon is especially expressive when high temperature treatment is performed at low pH [3]. The existing methods for DNA isolation from food cannot always fulfill the expectations of quantity and quality of isolated DNA. Furthermore they usually include 100 mg of sample and are difficult to scale-up [4]. Four major chromatographic modes are used for the separation of DNA: size-exclusion, anion-exchange, ion-pair reversephased, and slalom chromatography. Of these, anion-exchange chromatography combined with micropellicular packing is described as the most prominent technique so far [1].
Anion-exchange CIM® (Convective Interaction Media) monolithic columns allow fast and flow unaffected separation of several biomolecules, including nucleic acids [5].

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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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The availability of sufficient quantities of quality DNA is always a crucial point in DNA based methods, i.e. for PCR, DNA sequencing, Southern blotting, and microarrays [1]. The same is true for the PCR-based methods for detection of genetically modified food [2]. During the production chain foods passes several physical, biological, and chemical processes, which all negatively influences on the quantity of available DNA. The phenomenon is especially expressive when high temperature treatment is performed at low pH [3].

The existing methods for DNA isolation from food cannot always fulfill the expectations of quantity and quality of isolated DNA. Furthermore they usually include 100 mg of sample and are difficult to scale-up [4]. Four major chromatographic modes are used for the separation of DNA: size-exclusion, anion-exchange, ion-pair reversephased, and slalom chromatography. Of these, anion-exchange chromatography combined with micropellicular packing is described as the most prominent technique so far [1].

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The availability of sufficient quantities of quality DNA is always a crucial point in DNA-based methods, i.e. for PCR, DNA sequencing, Southern blotting, and microarrays [1]. The same is true for the PCR-based methods of GMO detection in food [2]. During the production chain foods passes several physical, biological, and chemical processes, which all negatively influences on the quantity of available DNA. The phenomenon is especially expressive when high temperature treatment is performed at low pH [3].

The existing methods, for DNA isolation from food, cannot always fulfill the expectations of quantity and quality of isolated DNA. Furthermore they usually include 100 mg of sample and are difficult to scale-up [4]. Four major chromatographic modes are used for the separation of DNA: size-exclusion, anionexchange, ion-pair reverse-phased, and slalom chromatography. Of these, anionexchange chromatography combined with micropellicular packing is described as the most prominent technique so far [1].

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1999

Synthetic oligonucleotides play an important role as novel therapeutic agents.

One of the most important, but also very time-consuming steps in synthetic oligonucleotides production is their purification. Due to their high-resolution power, reversed-phase and ion-exchange chromatography are the most widely used techniques for these purposes. For the reversed-phase separations oligonucleotides need to be kept as 5'-O-dimethoxytrityl derivatives until the purification process is completed and only then the detritylation takes place. Both these steps lower the yield of the production process. In the contrary, ion-exchange chromatography offers applications to deprotected oligonucleotides directly and that is the reason why this chromatography mode is more preferred.

Convective Interaction Media (CIM) are newly developed polymerbased monolithic supports allowing high resolution separations which can be carried out within seconds in the case of analytical units - disks. This is due to predominantly convective mass transport of biomolecules between the mobile and stationary phase and very low dead volumes. Additionally, the dynamic binding capacity is not affected by high flow rates.

In this work weak (DEAE) anion-exchange CIM supports have been successfully applied for the analysis and purification of synthetic oligonucleotides.

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