Size-Dependent Partitioning of Nano/Microparticles Mediated by Membrane Lateral Heterogeneity

Abstract

It is important that we understand the physical, chemical, and biological mechanisms that govern the interaction between nanoparticles (NPs) and heterogeneous cellular surfaces because of the possible cytotoxicity of engineered nanomaterials. In this study, we investigated the lateral localization of nano/microparticles within a biomimetic heterogeneous membrane interface using cell-sized two-phase liposomes. We found that lateral heterogeneity in the membrane mediates the partitioning of nano/microparticles in a size-dependent manner: small particles with a diameter of ≤200 nm were localized in an ordered phase, whereas large particles preferred a fluidic disordered phase. This partitioning behavior was verified by temperature-controlled membrane miscibility transition and laser-trapping of associated particles. In terms of the membrane elastic energy, we present a physical model that explains this localization preference of nano/microparticles. The calculated threshold diameter of particles that separates the particle-partitioning phase was 260 nm, which is in close agreement with our observation (200 nm). These findings may lead to a better understanding of the basic mechanisms that underlie the association of nanomaterials within a cell surface.

Quantum Dots Encapsulated within Phospholipid Membranes: Phase-Dependent Structure, Photostability, and Site-Selective Functionalization

“…19,20 Consequently, nanoparticles have been observed to adsorb onto the outer leaflet of membranes, incorporate within a membrane, or cause the deformation of membranes to generate nanoscale holes. 21–24 In the case of hydrophobic 2.0–5.0 nm QDs, electron and optical microscopy indicate that the nanoparticles partition into the hydrophobic region of the lipid membranes. 17 Given that the typical diameter of QDs is commiserate with the typical thickness of phospholipid membranes, it is not clear how the QD distorts the organization of the lipid bilayer, and correspondingly, how the organization of the lipid membrane influences the physical and chemical properties of the semiconductor nanocrystal.…”

Self-organization of Nanoparticle-Membrane Systems: Reconstitution of Cell Migration

“…Since there is no asymmetry in the vesicle encapsulating the reconstituted cytoskeleton, the directional motion can not be realized. Recently, we reported asymmetric adhesion of colloids to the membrane due to the phase separation on the membrane as described below [47]. Using this technique, the asymmetry can be induced in the reconstituted cytoskeleton.…”

Cell-Sized Liposomes and Droplets: Real-World Modeling of Living Cells

“…Several studies on membrane–colloid interactions with homogeneous cell-sized liposomes have reported that polystyrene particles spontaneously adhere to a phosphatidylcholine (PC) membrane surface [31,32]. We investigated the association of polystyrene NPs within biomimetic membrane interfaces with lateral heterogeneity, such as two-phase liposomes [33]. Two-liquid Lo/Ld separated liposomes were composed of saturated and unsaturated PC lipids (dipalmitoyl phosphatidylcholine, DPPC, and dioleoyl phosphatidylcholine, DOPC) together with cholesterol (Chol) (DOPC/DPPC/Chol = 37:37:26, molar ratio).…”

“…Scale bars are 10 µm; ( b ) Schematics of the size-dependent selective localization of NPs. Reprinted with permission from [33]. Copyright 2010 American Chemical Society.…”