Interaction between DNA and charged colloids could be hydrophobically driven.
The interaction of DNA with amino-functionalized polystyrene particles has been studied by using a dynamic light scattering (DLS) technique. In 10 mM NaBr solution the particles have a hydrodynamic radius of 76 nm and the DNA macromolecule investigated (double stranded) has a hydrodynamic radius of 107 nm. At very low DNA concentrations, DNA adopts a flat conformation on the particle surface. If the DNA concentration is increased above 0.1 microg/mL, the thickness of the DNA layer increases, suggesting the presence of large loops and tails. Although the particles contain primary amino groups, they have a negative net charge under the conditions used in this work. Thus, the driving force for DNA adsorption is not of electrostatic origin but rather due to a hydrophobic effect. Addition of cationic surfactant to the DNA-precoated amino-functionalized particles induces changes in the adsorbed layer conformation, in agreement with the coadsorption of cationic surfactant.
Cárdenas
Marité
M
Physical Chemistry 1, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden. marite.cardenas@fkem1.lu.se
Schillén
Karin
K
Pebalk
Dmitri
D
Nylander
Tommy
T
Lindman
Björn
B
D000327:Adsorption; D000818:Animals; D003102:Colloids / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D009690:Nucleic Acid Conformation; D010316:Particle Size; D011137:Polystyrenes; D012474:Salmon
D003102:Colloids; D011137:Polystyrenes; D004247:DNA