Interaction of biofunctionalized gold nanoparticles with model phospholipid membranes

Abstract

The understanding of the interaction of nanoparticles with cell membranes and the penetration of these nano-objects through cell wall is highly required for their biomedical application. In this work were aimed at the study of the interaction of gold nanoparticles with model phospholipid membranes prepared at the air/water interface in a Langmuir trough. Spherical (10 and 15 nm mean diameter) and rod-like gold (aspect ratio: 2.8) nanoparticles were synthesized and biofunctionalized with l-cysteine and l-glutathione. The gold nanoparticles were characterized by TEM images and UV–Vis absorbance measurements. The interaction of the biofunctionalized gold nanoparticles with the model monolayer membrane was studied by surface pressure versus surface area compressional isotherms and by the measurement of the change in surface pressure of a preformed model membrane. The effect of the initial surface pressure of the preformed membrane was evaluated to determine the maximum insertion pressure and synergy. We have found that the driving forces of the bioconjugated Au nanoparticle (NP) or Au nanorod (NR) penetration into the monolayer membrane is mostly determined by electrostatic interaction and orientational van der Waals forces. Monolayer films were transferred with Langmuir–Blodgett technique onto solid substrates and the nanoparticles were visualized with AFM technique.