Electrohydrodynamically induced aggregation during constant and pulsed field capillary electrophoresis of DNA

✍ Scribed by Soffia Magnúsdóttir; Hervé Isambert; Christoph Heller; Jean-Louis Viovy

• Publisher: Wiley (John Wiley & Sons)
• Year: 1999
• Tongue: English
• Weight: 200 KB
• Volume: 49
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/(sici)1097-0282(19990415)49:5<385::aid-bip5>3.0.co;2-l

✦ Synopsis

We present a study aimed at understanding the factors affecting the separation of large DNA molecules by capillary electrophoresis in polymer solutions. In a first series of experiments, a systematic study of the effect of operational parameters on the development of an electrohydrodynamic instability resulting in DNA aggregation and spurious peaks in the electropherograms is presented. The results are discussed in regard to a recent theory of electrohydrodynamic instabilities in macroion suspensions, recently proposed by Isambert et al. Overall, the results provide strong support to the theory. Some situations of interest for applications, and not explicitly considered in the theory, such as asymmetric field pulsing and the use of polymer additives in the buffer, were also considered. Furthermore, robust optimized protocols for high resolution separation of DNA in the range of 100 base pairs to 160 kilobase pairs, are proposed. As predicted by the model, it is shown that using a concentrated isoelectric buffer (histidine) strongly reduces aggregation as compared to the use of a conventional buffer at the same concentration, and allows