Chromatographic approaches in the purification of plasmid DNA for therapy and vaccination

The need for large scale plasmid DNA purification processes has increased in the last few years due to the rapid evolution of gene therapy and DNA vaccines. Chromatographic purification of plasmid DNA has specific problems which are mostly related to the structural nature of plasmid DNA, the resemblance of plasmid DNA to some impurities, and the lack of capacity and selectivity of the traditional bead adsorbents. In this paper, plasmid DNA purification using chromatographic processes is reviewed. Initially the most relevant structural and chemical properties of supercoiled plasmid DNA and related impurities are described, and the purification objectives are specified. The most significant properties are highlighted and their possible exploitation for plasmid DNA adsorption is described. After a brief description of currently used chromatographic purification strategies, novel approaches centered on the use and development of new stationary phases with higher capacity utilization are described.