title: Interaction of cationic surfactants with DNA detected by spectroscopic and acoustic wave techniques.
abstract: Interaction of the cationic surfactants benzalkonium chloride and 1-hexadecylpyridinium chloride, in the concentration range 0.1 microM to 1 mM with calf thymus DNA and with short 19-mer double-stranded DNA has been examined in solution using UV absorption and fluorescent spectroscopies and at the liquid-solution interface by thickness-shear mode acoustic wave sensor. Higher concentrations of surfactant resulted in an increase of UV absorption, and decrease of melting temperature and van't Hoff enthalpy of calf thymus DNA. Both surfactants induce fluorescence quenching of ethidium bromide which is also associated with intercalation of the molecules into the nucleic acid strand. The effect of the pyridinium compound is greater than for the other surfactant likely because of the lower size of polar head group in this molecule. With respect to acoustic wave detection at the device surface, for relatively low surfactant concentrations (below 100 microM), decreases of both series resonant frequency and motional resistance were observed. At higher surfactant concentration both parameters increased. These effects are attributed to acoustic coupling processes that occur at the device-film/liquid boundary.
authors.affiliation: Department of Nuclear Physics and Biophysics, Comenius University, Mlynska dolina F1, 842 48 Bratislava, Slovakia. tibor.hianik@fmph.uniba.sk
authors.forename: T
authors.initials: T
authors.lastname: Hianik
authors.forename: X
authors.initials: X
authors.lastname: Wang
authors.forename: V
authors.initials: V
authors.lastname: Tashlitsky
authors.forename: T
authors.initials: T
authors.lastname: Oretskaya
authors.forename: S
authors.initials: S
authors.lastname: Ponikova
authors.forename: M
authors.initials: M
authors.lastname: Antalík
authors.forename: J S
authors.initials: JS
authors.lastname: Ellis
authors.forename: M
authors.initials: M
authors.lastname: Thompson
mesh_terms: D000818:Animals; D001548:Benzalkonium Compounds / Q000737:chemistry; D002417:Cattle; D004247:DNA / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*; D013501:Surface-Active Agents / Q000737:chemistry*; D013816:Thermodynamics; D044366:Transition Temperature
chemical_list: D001548:Benzalkonium Compounds; D013501:Surface-Active Agents; D004247:DNA; C427203:calf thymus DNA