Interaction between DNA and cationic amphiphiles: a multi-technique study.
The interaction of cationic amphiphiles with calf thymus DNA has been investigated by physicochemical techniques (surface tension, conductometry, UV spectroscopy, thermal denaturation) and morphological microscopies (AFM and TEM). The cationic molecules were the amphiphiles cetyltrimethylammonium and cetyltributylammonium bromides (CTAB and CTBAB, respectively), compared to the nonamphiphilic tetramethyl- and tetrabutylammonium bromides (TMAB and TBAB, respectively) and, as a transfection-efficient comparison, a commercial poliethyleneimine (PEI). As a result, well below their critical micelle concentrations (cmc), CTAB and CTBAB showed a peculiar, nonlinear adsorption profile with the nucleic acid, which showed a correlation with the melting temperatures and morphological changes observed with AFM and TEM microscopies. On the other hand, TMAB and TBAB interact much less with the DNA duplexes and do not induce any modifications of the structures. The same behavior was observed with PEI; however, CTAB and CTBAB proved much less effective in condensing the nucleic acid.
CEMIN, Center of Excellence on Innovative Nanostructured Materials, Department of Chemistry, University of Perugia, Via Elce di Sotto 8, I-06123 Perugia, Italy.
Pietro
P
Di Profio
Raimondo
R
Germani
Laura
L
Goracci
Roberto
R
Grilli
Gianfranco
G
Savelli
Matteo
M
Tiecco
D000818:Animals; D002412:Cations; D002417:Cattle; D004247:DNA / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D046529:Microscopy, Electron, Transmission; D013056:Spectrophotometry, Ultraviolet; D013500:Surface Tension; D013501:Surface-Active Agents / Q000737:chemistry*
D002412:Cations; D013501:Surface-Active Agents; D004247:DNA