Studied on the interaction between Ag-DNA nanocomposites and lipids monolayers

The adsorption behavior of AgNPs-DNA nanocomposites on 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-dimyristoyl-sn-glycero-3-phosphoserine (DMPS) lipid monolayers has been investigated by analyzing adsorption dynamic process, surface pressure-area isotherms (π-A), excess mean area (ΔAexc), excess Gibbs free energy (ΔGex) and the atomic force microscopy (AFM). The nanocomposites were prepared by sliver nanoparticles (AgNPs) and deoxyribonucleic acid (DNA) via electrostatic attraction. The result of ?π/π and π-A isotherms indicated that the binding of AgNPs-DNA tends to adsorb on DMPC while the concentration of DNA exceeds 0.4 μg/mL. Excess mean area and thermodynamic analysis of excess Gibbs energy demonstrated that AgNPs-DNA enlarged the interval between DMPC and DMPS molecules, whose phenomena might be the electrostatic repulsion of each AgNPs-DNA molecule.