Reversible thermo-responsive sieving matrix for oligonucleotide separation

Abstract

A reversible thermo-responsive gel system, consisting of Pluronic copolymer mixture of F87 and F127, has been used to successfully carry out the separation of oligonucleotides, for the first time, by microchip-based capillary electrophoresis. Pluronic triblock copolymers F87 (E₆₁P₄₀E₆₁) and F127 (E₉₉P₆₉E₉₉), with E, P, and subscript denoting oxyethylene, oxypropylene, and segment length respectively, have a unique temperature dependent viscosity-adjustable property and a dynamic coating ability in aqueous solution, including 1 × TBE buffer. The mixture solution has a reversible thermo-responsive property and its sol–gel transition temperature can be adjusted ranging from about 17 °C to 38 °C by varying the relative weight ratio of F87 and F127 at an optimized concentration of ∼30% (w/v) for oligonucleotide separations. Oligonucleotide sizing markers ranging from 8 to 32 base could be successfully separated in a 1.5 cm long separation channel by the mixture solution in its gel-like state. A 30% (w/v) with a F87/F127 weight ratio of 1 ∶ 2 which has a “sol–gel” transition point of about 26 °C shows the best sieving ability. The sieving ability of the mixture solution was further confirmed in an Agilent Bioanalyzer 2100 system. Fast separation of oligonucleotides has been achieved within 40 s with one base resolution.