QIAGEN has established a partnership with Aldevron, a company that specializes in custom plasmid DNA preparation services. Through this partnership, Aldevron is offering customers the possibility to order standard plasmid DNA preparation services performed using high-quality QIAGEN plasmid purification products. This service offers three different scales of endotoxin-free* plasmid DNA. This standardized service is only available via the Web site www.plasmid.com.
Features and benefits
High-quality plasmid DNA is essential for many applications such DNA transfection into sensitive eukaryotic cell lines.
High-quality QIAGEN endotoxin-free* plasmid DNA
Plasmid DNA in three scales (up to 1 mg, 4 mg, and 10 mg)
The standard concentration delivered is ~1 mg/ml in TE buffer. Additional services and measurements are available upon request.
Endotoxin-free plasmid DNA
Endotoxins, also known as lipopolysaccharides or LPS, are cell-membrane components of Gram-negative bacteria such as E. coli. Endotoxins are released during the lysis step of plasmid purification and significantly reduce transfection efficiencies in endotoxin sensitive cell lines (see figure Plasmid purity versus transfection efficiency). Furthermore, endotoxins can influence the uptake of plasmid DNA in transfection experiments by competing with DNA for “free” transfection reagent. Endotoxins also induce nonspecific activation of immune responses in immune cells such as macrophages and B cells, which can lead to misinterpretation of transfection results. These responses include induced synthesis of proteins and lipids such as IL-1 and prostaglandin. Overall, endotoxins represent a noncontrollable variable in transfection experiment setup, influencing the outcome and reproducibility of results and making them difficult to compare and interpret. In gene therapy research, endotoxins can interfere by causing endotoxic-shock syndrome and activation of the complement cascade.
Plasmid purity versus transfection efficiency: The effect of the amount and quality of plasmid DNA on transfection efficiency in CHO SSF3 X9 cells grown in suspension under serum-free conditions is shown. Each point represents the mean of three independent experiments. Rel. LU: relative light units. (Data kindly provided by M. Zang-Gandor, Novartis AG, Basel, Switzerland.)
* Endotoxin-free DNA means <100 EU/mg purified plasmid DNA.