Distribution of Functionalized Gold Nanoparticles between Water and Lipid Bilayers as Model Cell Membranes

Abstract

Lipid bilayers are biomembranes common to cellular life and constitute a continuous barrier between cells and their environment. Understanding the interaction of nanoparticles with lipid bilayers is an important step toward predicting subsequent biological effects. In this study, we assessed the affinity of functionalized gold nanoparticles (Au NPs) with sizes from 5 to 100 nm to lipid bilayers by determining the Au NP distribution between aqueous electrolytes and lipid bilayers. The Au NP distribution to lipid bilayers reached an apparent steady state in 24 h with smaller Au NPs distributing onto lipid bilayers more rapidly than larger ones. Au NPs distributed to lipid bilayers to a larger extent at lower pH. Tannic acid-functionalized Au NPs exhibited greater distribution to lipid bilayers than polyvinylpyrrolidone-functionalized Au NPs of the same size. Across the various Au NP sizes, we measure the lipid bilayer-water distribution coefficient (K(lipw) = C(lip)/C(w)) as 450 L/kg lipid, which is independent of dosimetric units. This work suggests that the nanoparticle-cell membrane interaction is dependent on solution chemistry and nanoparticle surface functionality. The K(lipw) value may be used to predict the affinity of spherical Au NPs across a certain size range toward lipid membranes.

Nanoparticle–membrane interactions

“…They have many forms including supported or unsupported planar bilayer, spherical vesicles and interfacial monolayers [76][77][78] (Figure 3(A)). The simplified and shape-analogue lipid model membrane used to simulate a cell-like membrane structure is a spherical vesicle or liposome.…”

Centrifugation-based assay for examining nanoparticle–lipid membrane binding and disruption

“…[19][20][21][22] Inductively coupled plasma optical emission spectrometry (ICP-OES) or mass spectrometry (MS) has also been used, for example, to probe the interaction between functionalized Au nanoparticles and silica sphere-supported lipid membranes (SSLMs) by measuring the concentrations of Au nanoparticles both in the aqueous electrolytes (supernatant) and in/on the lipid bilayers. 23 The electrophysiological approach 24 coupled with the droplet-in-oil methodology has been employed to study the interaction between nanoparticles and cell membranes. In the report by De Palnque et al, the droplet-in-oil methodology was first used to create lipid bilayers through the self-assembly of two water droplets coated with a lipid monolayer at water-oil interface.…”

Driving Adsorbed Gold Nanoparticle Assembly by Merging Lipid Gel/Fluid Interfaces

“…For example, zwitterionic phosphocholine (PC) liposomes can adsorb a diverse range of nanomaterials, including latex beads, 8,9 TiO2, [10][11][12] graphene oxide, 13,14 nano-diamonds, 15 and gold NPs (AuNPs). [16][17][18][19][20][21][22] Among these materials, AuNPs are particularly interesting: 1) the surface chemistry of AuNPs can be readily controlled by capping with thiol ligands; 2) AuNPs display distance-dependent color due to surface plasmon coupling, allowing convenient visual monitoring; 23 and 3) AuNPs have strong van der Waals interaction (i.e. large Hamaker constant) with other surfaces thus making strong physisorption possible.…”