Spatial open-network formed by mixed triblock copolymers as a new medium for double-stranded DNA separation by capillary electrophoresis

A mixture of two polyoxybutylene-polyoxyethylene-polyoxybutylene (BEB) trib lock copolymers (B6E46B6 and B10E271B10, respectively) was used as a new se paration medium for separating double-stranded DNA (dsDNA) fragments by cap illary electrophoresis (CE). The two block copolymer mixtures were designed to form mixed flowerlike micelles in dilute solution and a homogeneous gel -like open-network with hydrophobic clusters as cross-linking points at hig her polymer concentrations. Being a polyoxyalkylene block copolymer gel, th e separation medium has some special advantages, including the temperature- dependent sol-gel transition that makes sample injection easy, and the self -coating of the inner capillary wall that makes experimental procedures sim ple and reproducible. Furthermore, it can shorten the elution time and furt her improve the separation resolution, especially for small dsDNA fragments , when compared with EPE-type separation media, e.g., F127 (E99P69E99, with P being polyoxypropylene) block copolymer gels formed by the closed packin g of spherical micelles. Single base pair resolution can be achieved by usi ng the new separation medium for dsDNA fragments up to over 100 base pairs.