title: Insertion of short amino-functionalized single-walled carbon nanotubes into phospholipid bilayer occurs by passive diffusion.
abstract: Carbon nanotubes have been proposed to be efficient nanovectors able to deliver genetic or therapeutic cargo into living cells. However, a direct evidence of the molecular mechanism of their translocation across cell membranes is still needed. Here, we report on an extensive computational study of short (5 nm length) pristine and functionalized single-walled carbon nanotubes uptake by phospholipid bilayer models using all-atom molecular dynamics simulations. Our data support the hypothesis of a direct translocation of the nanotubes through the phospholipid membrane. We find that insertion of neat nanotubes within the bilayer is a "nanoneedle" like process, which can often be divided in three consecutive steps: landing and floating, penetration of the lipid headgroup area and finally sliding into the membrane core. The presence of functional groups at moderate concentrations does not modify the overall scheme of diffusion mechanism, provided that their deprotonated state favors translocation through the lipid bilayer.
authors: Laboratoire de Nanomédecine, Imagerie et Thérapeutique, EA 4662, Université de Franche-Comté, Centre Hospitalier Universitaire de Besançon, Besançon, France.
authors: Sebastian
authors: S
authors: Kraszewski
authors: Alberto
authors: A
authors: Bianco
authors: Mounir
authors: M
authors: Tarek
authors: Christophe
authors: C
authors: Ramseyer
mesh_terms: D000588:Amines / Q000737:chemistry*; D001692:Biological Transport; D004058:Diffusion; D008051:Lipid Bilayers / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010743:Phospholipids / Q000737:chemistry*; D011522:Protons; D013816:Thermodynamics
chemical_list: D000588:Amines; D008051:Lipid Bilayers; D037742:Nanotubes, Carbon; D010743:Phospholipids; D011522:Protons