HiSpeed Plasmid Mega and Giga EF Kits

• Approximately 50 minutes prep time
• Lysate clearing and isopropanol precipitation without centrifugation
• No risk of DNA pellet loss during precipitation
• Up to 10 mg yield of high-copy plasmid DNA
• LyseBlue for optimum lysis and maximum DNA yield
• Endotoxin removal included (< 0.1 EU/μg DNA)

QIAfilter Cartridges (see figure “ QIAfilter Mega-Giga Cartridge”) are special filter units designed to replace the centrifugation step following alkaline lysis of bacterial cells. QIAfilter Cartridges completely remove SDS precipitates and clear bacterial lysates in a fraction of the time needed for centrifugation. Prepacked HiSpeed Tips operate by gravity flow and never run dry, minimizing the hands-on time required for plasmid preparation.
The unique QIAconcentrator (see figure “ HighSpeed Plasmid Giga EF procedure”) replaces the centrifugation step traditionally used to collect isopropanol-precipitated DNA following purification. The QIAconcentrator module traps the precipitated DNA, while the isopropanol-buffer mixture flows through. The DNA is then simply eluted from the QIAprecipitator into a collection tube with TE buffer or water. This unique module also eliminates the risk of pellet loss, which can occur during decanting of the supernatant following centrifugation.
Endotoxins, also known as lipopolysaccharides or LPS, are cell-membrane components of Gram-negative bacteria such as E. coli (see figure “ Bacterial cell wall”). Endotoxins are released during the lysis step of plasmid purification and significantly reduce transfection efficiencies in endotoxin sensitive cell lines. 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. >

Neutralized bacterial lysates are incubated in the QIAfilter Cartridge and cleared in seconds by vacuum. At this stage, the Endotoxin Removal Buffer is added to the filtered lysate. No incubation is needed. The filtrate is applied to a HiSpeed tip for plasmid DNA purification (see figure “ HighSpeed Plasmid Giga EF procedure”). Eluted DNA is mixed with isopropanol and applied to the QIAconcentrator using vacuum and washed. The concentrated and desalted DNA is then eluted from the QIAconcentrator directly into a fresh collection tube with TE buffer or water.