Lipopolysaccharides (LPS), often referred to as endotoxins, are produced by gram-negative bacteria such as E. coli and detected by the immune system of eukaryotic cells. This can trigger an immune response and result in reduction of gene expression. In popular kit preparations, LPS content may vary very widely and have undesirable effects on the results of the experiment. During each plasmid production, PlasmidFactory measures the LPS content and can guarantee, upon request, a content of less than 0.1 EU / µg of DNA. Thus, the levels undermatch those of all other production processes.
Special quality features
PlasmidFactory has developed a special production process for plasmid DNA which generally discards the use of substances of animal origin to the greatest possible extent. Upon request, a recombinant RNase is used in the production process to result in completely «animal-free» production. Avoiding use of animal-based substances is of importance for clinical applications, since these substances may pose a safety risk. In addition, the use of enzymes – including RNase – can be avoided completely during production and purification, since the RNA is removed chromatographically («enzyme-free» procedure). At PlasmidFactory, plasmid amplification in E. coli cells is always carried out in the fermenter and under controlled conditions, because it is not possible to guarantee the reproducibility of the produced biomass when shake flasks are used. The quality of the product is constantly monitored and documented. A complete list of the quality controls and analytic methods can be found on the Quality Control page.
 M. Schleef, M. Blaesen (2009), Production of Plasmid DNA as a Pharmaceutical, in: W. Walther and U. S. Stein (eds.), Methods in Molecular Biology, Gene Therapy of Cancer, vol. 542: 471-495
 C. Maucksch, A. Bohla, F. Hoffmann, M. Schleef, M. K. Aneja, M. Elfinger, D. Hartl, C. Rudolph (2009), Transgene expression of transfected supercoiled plasmid DNA concatemers in mammalian cells, J Gene Med 11: 444-453
 M. Schleef, R. Baier, W. Walther, M.L. Michel, and M. Schmeer (2006), Long-Term Stability Study and Topology Analysis of Plasmid DNA by Capillary Gel Electrophoresis
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 M. Schleef, T. Schmidt (2004), Animal-free production of ccc-supercoiled plasmids for research and clinical applications, J Gene Med 6: 45-53
 W. Walther, U. Stein, I. Fichtner, C. Voss, T. Schmidt, M. Schleef, T. Nellessen, P. M. Schlag (2002), Intratumoral Low-Volume Jet-Injection for Efficient Nonviral Gene Transfer, Molecular Biotechnology 21: 105-115