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

Abstract

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 ( $${\Delta \mathrm{A}}_{\mathrm{e}\mathrm{x}\mathrm{c}}$$ ), excess Gibbs free energy ( $$\Delta {\mathrm{G}}_{\mathrm{e}\mathrm{x}}$$ ) 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. AFM observation showed that the adsorption behavior of AgNPs-DNA on DMPS monolayers had a saturation point, while DMPC was not. Taken together, this work might provide a novel idea and useful basis for the development of metal nanoparticles-based biological materials.