Destructive extraction of phospholipids from Escherichia coli membranes by graphene nanosheets

Abstract

Understanding how nanomaterials interact with cell membranes is related to how they cause cytotoxicity and is therefore critical for designing safer biomedical applications. Recently, graphene (a two-dimensional nanomaterial) was shown to have antibacterial activity on Escherichia coli, but its underlying molecular mechanisms remain unknown. Here we show experimentally and theoretically that pristine graphene and graphene oxide nanosheets can induce the degradation of the inner and outer cell membranes of Escherichia coli, and reduce their viability. Transmission electron microscopy shows three rough stages, and molecular dynamics simulations reveal the atomic details of the process. Graphene nanosheets can penetrate into and extract large amounts of phospholipids from the cell membranes because of the strong dispersion interactions between graphene and lipid molecules. This destructive extraction offers a novel mechanism for the molecular basis of graphene's cytotoxicity and antibacterial activity.

Interfacing Zwitterionic Liposomes with Inorganic Nanomaterials: Surface Forces, Membrane Integrity, and Applications

“…They predicted that the lipid tails are parallel to the graphene surface ( Figure 6B). 57 This lipid extraction mechanism was used to explain the toxicity of graphene to bacterial cells. In other studies, lipid interaction was also proposed to be a major reason of the anti-microbial activity of graphene-based materials.…”

Spontaneous insertion of carbon nanotube bundles inside biomembranes: A hybrid particle-field coarse-grained molecular dynamics study

“…So far, experimental methods can provide for these systems only limited information at the molecular scale level. For this reason, several simulation studies involving CNT and lipid bilayers have been reported [17,18,[21][22][23][24][25][26][27]. On the contrary, molecular dynamics simulations based on atomistic or coarse-grained models can provide detailed information on these processes.…”

“…Moreover, the insertion process of a small graphene nanosheet into a lipid bilayer structure has been studied using atomistic simulations [22].…”

Shielding membrane surface carboxyl groups by covalent-binding graphene oxide to improve anti-fouling property and the simultaneous promotion of flux

“…The special features of the GO Nair et al, 2012;Lee et al, 2008;Hu et al, 2010;Tu et al, 2013;Lui et al, 2009;Novoselov et al, 2004;Dreyer et al, 2010;Hummers and Offeman, 1958;Drioli et al, 2015) make it to an excellent surface modification material. The GO surface modification can effectively exert the good separation properties of organic polymer active layer, and the chlorine resistance and anti-fouling properties of a GO layer simultaneously.…”

“…Water can nearly unimpeded permeated though graphene two-dimensional nanocapillaries (Nair et al, 2012). GO has other unique qualities, including ultrahigh strength (Lee et al, 2008), atomic-scale thickness (Novoselov et al, 2004), high antibacterial property and low cytotoxicity (Hu et al, 2010;Tu et al, 2013), and the possibility of producing ultraflat surface (Lui et al, 2009). It also possesses good chemical stability (Dreyer et al, 2010) and hydrophilic properties (Nair et al, 2012;Dreyer et al, 2010), and can be prepared from inexpensive graphite (Hu et al, 2010;Hummers and Offeman, 1958).…”