title: Interactions between ionic liquid surfactant [C12mim]Br and DNA in dilute brine.
abstract: Interactions between ionic liquid surfactant [C(12)mim]Br and DNA in dilute brine were investigated in terms of various experimental methods and molecular dynamics (MD) simulation. It was shown that the aggregation of [C(12)mim]Br on DNA chains is motivated not only by electrostatic attractions between DNA phosphate groups and [C(12)mim]Br headgroups but also by hydrophobic interactions among [C(12)mim]Br alkyl chains. Isothermal titration calorimetry analysis indicated that the [C(12)mim]Br aggregation in the presence and absence of DNA are both thermodynamically favored driven by enthalpy and entropy. DNA undergoes size transition and conformational change induced by [C(12)mim]Br, and the charges of DNA are neutralized by the added [C(12)mim]Br. Various microstructures were observed such as DNA with loose coil conformation in nature state, necklace-like structures, and compact spherical aggregates. MD simulation showed that the polyelectrolyte collapses upon the addition of oppositely charged surfactants and the aggregation of surfactants around the polyelectrolyte was reaffirmed. The simulation predicted the gradual neutralization of the negatively charged polyelectrolyte by the surfactant, consistent with the experimental results.
authors.affiliation: Key Laboratory for Advanced Materials and Department of Chemistry, East China University of Science and Technology, Shanghai 200237, China.
authors.forename: Yunfei
authors.initials: Y
authors.lastname: He
authors.forename: Yazhuo
authors.initials: Y
authors.lastname: Shang
authors.forename: Zhenhai
authors.initials: Z
authors.lastname: Liu
authors.forename: Shuang
authors.initials: S
authors.lastname: Shao
authors.forename: Honglai
authors.initials: H
authors.lastname: Liu
authors.forename: Ying
authors.initials: Y
authors.lastname: Hu
mesh_terms: D000465:Algorithms; D002151:Calorimetry; D002942:Circular Dichroism; D003198:Computer Simulation; D004247:DNA / Q000737:chemistry*; D004553:Electric Conductivity; D004563:Electrochemistry; D004587:Electrophoresis, Agar Gel; D007093:Imidazoles / Q000737:chemistry*; D008027:Light; D018625:Microscopy, Atomic Force; D008956:Models, Chemical; D012492:Salts; D012542:Scattering, Radiation; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: C521425:1-dodecyl-3-methylimidazolium; D007093:Imidazoles; D012492:Salts; D013501:Surface-Active Agents; C017082:brine; D004247:DNA