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Title: Manufacture of adenoviral vectors for gene therapy applications : critical comparison of solvent extraction and adsorption-based processes
Author: Negrete-Virgen, Juan Alejandro.
ISNI:       0000 0001 3440 5901
Awarding Body: University of Birmingham
Current Institution: University of Birmingham
Date of Award: 2003
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The biotechnology industry has recently been demanding nanoparticulate products (20-200 nm) such as viruses, plasmids, virus-like particles and drug delivery assemblies. These products are mainly used as gene delivery systems in gene therapy protocols. Adenoviral vectors {Ad) are the most exploited gene therapy vectors in industry worldwide. The of Ad fuces several problems including {i) small volumes of product per batch of cell culture, {ii) inaccurate, time consuming and multifuctor-dependant methods for infectivity determination and (iii) downstream processing. The downstream processing requires methods to purify infective particles :from the contaminants including non-infective particles, partially assembled particles, :free adenoviral components, host cell components and medium components. The solvent extraction method, aqueous two-phase systems {ATPS) and selective chromatography can potentially circumvent such downstream processing problems. ATPS has been applied to the purification of soluble macromolecular products. However, the recovery of nanoparticles represents a practical constraint due to their partition in the interphase. Selective chromatography has been also a method for high performance purification of bioproducts. However, in the context of nanoparticulates, product and contaminants adsorb and desorb (i.e. copurify) under similar mobile phase conditions due to sheared chemistry. In this study, infective Ad were concentrated in the top phase of a polymer-salt ATPS. Additionally, the potential ATPS miniaturisation for scouting experiments was evaluated. The infective Ad were also partially purified exploiting a fluidised bed. In this process, an anionexchange commercial adsorbent laminated with electrophoretic grade neutral agarose was utilised. The porosity of the pellicle was designed to exclude Ad yet fucilitate diffusion of macromolecular components to adsorption sites within the interior of the adsorbent core (subtractive adsorption). Furthermore, a method for monitoring infective Ad with rapid and easy handling by means of flow cytometric analysis was developed. In order to perform the experiments, the Ad production was scaled-up to a 2 L bioreactor. The recovery processes evaluated in this study and conclusion drown will contribute to the recovery of Ad but also could be applied to recover other nanoparticulate bioproducts
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Bioengineering & biomedical engineering Biomedical engineering Biochemical engineering Molecular biology Cytology Genetics