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Findings from University of Minho in DNA research reported
December 17th, 2007
2007 DEC 17 -- According to recent research from Braga, Portugal, "This work studied the possibility of using polyethyleimine (PEI) as an affinity ligand for the purification of plasmid DNA (pDNA) from alkaline lysates using aqueous two-phase systems (ATPSs). The goal was to find conditions under which this cationic polymer could steer the partition of pDNA to the phase where less impurities accumulate." "In poly(ethylene glycol) (PEG)/ammonium sulphate systems, neither free nor PEGylated PEI (pPEI) were able to change the partition of pDNA. This is probably due to the high salt concentration present in these systems that impair the interaction between pDNA and PEI. In PEG 3350/dextran 110 systems, the desired effect could be observed but 0.2-0.5 M ammonium sulphate had to be added to prevent the co-partition of RNA to the same phase. These results were used to develop a methodology to obtain polyplexes from alkaline lysates in a two-step ATPSs extraction process. In the first step, a PEG 60/ammonium sulphate system is used to remove most impurities to the top phase. The pDNA-containing bottom phase is then isolated and contacted with a second PEG 3350/dextran 110 system supplemented with a small amount of pPEI (0.2%). Plasmid yield was 100% and the final preparation had no RNA and only small amounts of contaminant protein," wrote S.P. Duarte and colleagues, University of Minho. The researchers concluded: "Additionally, pDNA was obtained in the form of 53 rim-sized polyplexes which are likely to suit specific gene delivery applications." Duarte and colleagues published their study in the Journal of Chromatography a (Preparation of plasmid DNA polyplexes from alkaline lysates by a two-step aqueous two-phase extraction process. Journal of Chromatography a, 2007;1164(1-2):105-112). For additional information, contact J.C. Marcos, University of Minho, Center Quim, Campus Gualtar, P-4710057 Braga, Portugal. Publisher contact information for the Journal of Chromatography a is: Elsevier Science BV, PO Box 211, 1000 AE Amsterdam, Netherlands. Keywords: Portugal, Braga, DNA Research, Biotechnology, Chromatography, DNA, Gene Therapy, Genetics, Genomics, Treatment, University of Minho. This article was prepared by Biotech Business Week editors from staff and other reports. Copyright 2007, Biotech Business Week via NewsRx.com.
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