Effect of Chirality and Length on the Penetrability of Single-Walled Carbon Nanotubes into Lipid Bilayer Cell Membranes

Abstract

The ability of carbon nanotubes to enter the cell membrane acting as drug-delivery vehicles has yielded a plethora of experimental investigations, mostly with inconclusive results because of the wide spectra of carbon nanotube structures. Because of the virtual impossibility of synthesizing CNTs with distinct chirality, we report a parametric study on the use of molecular dynamics to provide better insight into the effect of the carbon nanotube chirality and the aspect ratio on the interaction with a lipid bilayer membrane. The simulation results indicated that a single-walled carbon nanotube utilizes different time-evolving mechanisms to facilitate their internalization within the membrane. These mechanisms comprise both penetration and endocytosis. It was observed that carbon nanotubes with higher aspect ratios penetrate the membrane faster whereas shorter nanotubes undergo significant rotation during the final stages of endocytosis. Furthermore, nanotubes with lower chiral indices developed significant adhesion with the membrane. This adhesion is hypothesized to consume some of the carbon nanotube energy, thus resulting in longer times for the nanotube to translocate through the membrane.

Insertion Mechanism and Stability of Boron Nitride Nanotubes in Lipid Bilayers

“…23, 28,29 Larger diameter CNTs disrupt the bilayer to a larger extent and allow more interactions with the membrane during simulations, therefore requiring larger forces to move through the bilayer. 28,29 Moreover, CNTs shorter than the membrane thickness (∼60 Å) are more likely to rotate while moving through the bilayer. 28 Very few studies exist on the uptake mechanism of BNNTs.…”

“…28,29 Moreover, CNTs shorter than the membrane thickness (∼60 Å) are more likely to rotate while moving through the bilayer. 28 Very few studies exist on the uptake mechanism of BNNTs. Ciofani and colleagues 7,17,19 found that uptake of polyethylenimine-coated and poly-L-lysine-coated BNNTs was via energy dependent endocytosis, and attributed this to the chemical reactivity of the polyethylenimine coating.…”

Molecular Modeling of PEGylated Peptides, Dendrimers, and Single-Walled Carbon Nanotubes for Biomedical Applications

“…Computational studies have mainly focused on the self-assembly of SWNTs and surfactants (or lipids) [143,[150][151][152][153][154], and the interaction between SWNTs and lipid bilayers [155][156][157][158][159][160][161][162][163][164][165][166][167][168]. Simulations have shown that the self-assembly of SWNTs and their interactions with lipid bilayers can be modulated by the structure and concentration of surfactant, and the size and chirality of SWNT.…”

Analysis of nanoprobe penetration through a lipid bilayer

“…Because of this 'hydrophilic-hydrophobic-hydrophilic' structure, cell membranes present a formidable barrier to most polar molecules. This means an interface between the artificial materials and the lipid bilayer must be created and surfaces of nanostructures will progressively disrupt the organization of the biomolecules when they come into contact with cell membrane [14][15][16][17][18][19]. Though, numerous experimental platforms employing nanoscale structures have been constructed to deliver various molecules into different types of cells [2,5,11,[20][21][22][23].…”

“…However, when building such platforms, researchers usually focus on their geometrical size [24], shape [25] or the biological effectors [2] coated on them, and typically pay little attention to the interfaces between the artificial materials and the biological bilayer or the damage experienced by the membrane. In reality, different interfaces will lead to different degrees of bilayer disruption [16,19,25] some causing cell death [22,26]. It is widely accepted that in many cases it is the coated molecules that are interacting with biological system [27][28][29].…”