DNA capillary electrophoresis in entangled dynamic polymers of surfactant molecules

Aqueous solutions of monomeric nonionic surfactants, n-alkyl polyoxyethylen e ethers (C16E6, C16E8, C14E6), can be used as sieving matrixes for the sep aration of DNA fragments by capillary electrophoresis, Unlike ordinary poly mer solutions, these surfactant solutions behave as dynamic polymers. By co mbining the "reversible gel" theory of DNA electrophoresis and the static a nd dynamic properties of wormlike surfactant micelles, a model is developed for describing the migration behavior of DNA molecules in these solutions. According to the model, the separation limit can be extended at low surfac tant concentrations. Surfactant solutions as a separation medium provide ma ny advantages over ordinary polymers, such as ease of preparation, solution homogeneity, stable structure, low viscosity, and self-coating property fo r reducing electroosmotic now. More importantly, the properties of wormlike micelles (micelle size, entanglement concentration) can be adjusted by sim ply changing the monomer concentration, denaturant, and temperature to allo w the separation of different size ranges of DNA fragments. Fast separation is achieved for DNA fragments ranging from 10 bp to 5 kb by using bare fus ed-silica columns. DNA sequencing fragments of BigDye G-labeled M13 up to 6 00 bases were separated within 60 min.