Interaction between Room Temperature Ionic Liquid [bmim]BF₄ and DNA Investigated by Electrochemical Micromethod

Ionic liquids (ILs) as a kind of novel green solvent are being widely used in various researches related to the life sciences and chemistry, which demands the knowledge of interaction between ILs and biomacromolecules. However, the almost completely inert optical, electric, thermal properties of ILs make it difficult to directly obtain information about the interactions. Herein, by using a hydrophilic ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF4) as a model, the electrostatic interaction between ILs and calf thymus DNA (ctDNA) was investigated by a surface electrochemical micromethod. A convenient and simple method was established to obtain the thermodynamic and kinetic information about the DNA-IL interaction only with microscale sample consumption. The quantitative thermodynamic and kinetic parameters about the interaction of [bmim]BF4 and ctDNA, such as the binding constant (K), the Gibbs energy of surface binding (DeltaGb), and the dissociation rate constant (k), were obtained for the first time.