title: Reversible structural switching of a DNA-DDAB film.
abstract: We describe the novel structure and behavior of a DNA-DDAB complex film cast from an organic solvent and exhibiting a structural switching transition as it is dried or wetted with water. The film was easily prepared by formation of a complex between the negatively charged phosphate groups of DNA and the positively charged headgroup of the surfactant DDAB. This complex was then purified, dried, dissolved in 2-propanol, and cast onto a glass slide to form a self-standing film by means of slow evaporation. While the structure of the dried film was found to be composed of single-stranded DNA and a monolayer of DDAB, upon hydration of the film, the structure switched to double-stranded DNA complexed to a bilayer of DDAB. We expect this phenomenon to serve as a useful model for the design of new responsive materials and programmable self-assembly.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106-9510, USA.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Neumann
authors.forename: Surekha
authors.initials: S
authors.lastname: Gajria
authors.forename: Matthew
authors.initials: M
authors.lastname: Tirrell
authors.forename: Luc
authors.initials: L
authors.lastname: Jaeger
mesh_terms: D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D015394:Molecular Structure; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012542:Scattering, Radiation; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000644:Quaternary Ammonium Compounds; C046112:didodecyldimethylammonium; D004247:DNA