Tear of Lipid Membranes by Nanoparticles

TL;DR

This paper demonstrates that small nanoparticles can tear lipid membranes, revealing a new mechanism of nanoparticle-induced membrane damage, which is modulated by particle abundance and enhances understanding of nanoparticle toxicity.

Contribution

It uncovers a novel membrane tearing mechanism by nanoparticles and elucidates the interplay between particle size, abundance, and membrane integrity.

Findings

Nanoparticles can physically tear lipid membranes.

High particle abundance prevents membrane laceration.

Cryo-TEM visualizes nanoparticle-induced membrane damage.

Abstract

Health concerns associated with the advent of nanotechnologies have risen sharply when it was found that particles of nanoscopic dimensions reach the cell lumina. Plasma and organelle lipid membranes, which are exposed to both the incoming and the engulfed nanoparticles, are the primary targets of possible disruptions. However, reported adhesion, invagination and embedment of nanoparticles (NPs) do not compromise the membrane integrity, precluding direct bilayer damage as a mechanism for toxicity. Here it is shown that a lipid membrane can be torn by small enough nanoparticles, thus unveiling mechanisms for how lipid membrane can be compromised by tearing from nanoparticles. Surprisingly, visualization by cryo transmission electron microscopy (cryo-TEM) of liposomes exposed to nanoparticles revealed also that liposomal laceration is prevented by particle abundance. Membrane destruction results thus from a subtle particle-membrane interplay that is here elucidated. This brings into a firmer molecular basis the theorized mechanisms of nanoparticle effects on lipid bilayers and paves the way for a better assessment of nanoparticle toxicity.