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X‐ray reflectivity studies on the deoxyribonucleic acid adsorption by 3‐β‐[ N ‐( N ', N '‐dimethylaminoethane)carbamoyl]cholesterol monolayer with divalent ions
Author(s) -
Lin TangLang,
Wu JuiChing,
Jeng USer,
Lee HsinYi
Publication year - 2007
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889807002452
Subject(s) - monolayer , divalent , cationic polymerization , ion , adsorption , chemistry , dna , crystallography , x ray reflectivity , langmuir , calcium , inorganic chemistry , analytical chemistry (journal) , materials science , organic chemistry , biochemistry , thin film , nanotechnology
The effect of adding divalent ions on the deoxyribonucleic acid (DNA) adsorption by a cationic lipid monolayer at the air–water interface was investigated by X‐ray reflectivity on Langmuir–Blodgett films supported on silicon wafers. The films were prepared from a DC‐Chol {3‐β‐[ N ‐( N ′, N ′‐dimethylaminoethane)carbamoyl]cholesterol} monolayer with 1 µ M DNA in the subphase with different amounts of calcium ions added. It is found in this study that adding divalent ions, such as calcium ions, can enhance the DNA adsorption to interfaces. The adsorbed DNA layer thickness as determined by X‐ray reflectivity is found to vary linearly with the square root of the ion concentration. This indicates that charge‐screening effects and ion‐mediated condensation play an important role in the DNA–cationic lipid monolayer interaction.