EndoFree Plasmid Purification Maxi Kit From Qiagen

There are multiple ways to purify plasmid or cosmid DNA and multiple kits available. For DNA that is to be used in subsequent sensitive experiments, such as transfection or cloning, DNA that is free of endotoxin is often necessary. The EndoFree Plasmid Kit produces DNA that will improve the efficiency of transfection of sensitive or immunologically active cells. The Qiagen plasmid kit uses gravity-flow anion-exchange QIAGEN-tips to produce ultrapure DNA that can then be used in subsequent experiments. The EndoFree Kit has the same QIAfilter cartridges as the QIAfilter Plasmid and HiSpeed Plasmid Kits, although it lacks the fast high speed isopropanol precipitation of the HiSpeed Kit.

For those that have used a Qiagen kit in the past, this kit has the same format and buffer system that is the trademark of all of the Qiagen purification kits. The kit is based on alkaline lysis of the sample followed by binding of the DNA to the resin of the Qiagen-tip, washing to remove impurities, elution of the DNA and finally, concentration and isopropanol precipitation of the DNA. This involves several pouring steps, buffer additions, chilling, filtering, washing, eluting and purification of the DNA. The main difference between this kit and other plasmid preps is the endotoxin-free water and TE buffer in which the DNA is reconstituted.

I recently switched to using this kit when I started doing a lot of transfection and cloning. I needed DNA that was pure and wouldn’t be lethal to my cells after transfection. The kit is not that different from any other plasmid purification kit, although I really like the QIAfilter tips. I like the fact that the columns can’t dry out and that there are multiple steps along the way where the protocol can be stopped and frozen or refrigerated for continuation at a better time. The new kits even have color-coded buffer tops to help prevent mix-ups of the separate lysis, wash, elution, etc. buffers. Using the purified DNA, I have never had a problem with my transfections, be they primary cell lines, hippocampal cells or stable recombinant cell lines. Qiagen kits are known for their reliability and this kit proves no different. If you have had any problems with transfections in the past, I would recommend switching from a standard plasmid prep to this endofree kit.

For generation of endotoxin-free DNA that will improve transfection of sensitive eukaryotic and other cell lines or for gene therapy research, this is a well-proven, reliable kit that is efficient, easy-to-use and highly recommended.