An important part of the biopharma industry, Plasmid DNA is used as a gene-delivery vehicle for DNA vaccination and as a key intermediate for processes like viral particle production for gene therapy and ex-vivo protein synthesis. Most plasmid DNA preparations contain several topological variants or isoforms including the supercoiled, open-circular and linear forms of the molecule.

 

Federal regulations require purity testing for manufactured injectable plasmid products and recommend establishing a release criterion of > 80% supercoiled content. Unfortunately, traditional agarose gel has limitations on quantitation. Capillary electrophoresis with Laser Induced Fluorescence detection (CE-LIF) provides a rapid, sensitive, reproducible and automated method for the quantitative analysis of plasmid DNA isoforms.

 

In this webinar, we present a method for plasmid analysis by CE-LIF with the use of a common dye. Results obtained with two large plasmids at 7 to 10 kb demonstrate that this method is sensitive and robust, providing baseline resolution of supercoiled, open-circular and linear plasmid isoforms within 20 minutes, and is suitable for testing plasmid purity and monitoring plasmid degradation.

 

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