Analysis of nanoprobe penetration through a lipid bilayer

Abstract

With the rapid development of nanotechnology and biotechnology, nanoscale structures are increasingly used in cellular biology. However, the interface between artificial materials and a biological membrane is not well understood, and the harm caused by the interaction is poorly controlled. Here, we utilize the dissipative particle dynamics simulation method to study the interface when a nanoscale probe penetrates the cell membrane, and propose that an appropriate surface architecture can reduce the harm experienced by a cell membrane. The simulation shows that a hydrophilic probe generates a hydrophilic hole around the probe while a hydrophobic probe leads to a 'T-junction' state as some lipid molecules move toward the two ends of the probe. Both types of probe significantly disrupt lipid bilayer organization as reflected by the large variations in free energy associated with penetration of the membrane. Considering the hydrophilic/hydrophobic nature of the lipid bilayer, three other hydrophilic/hydrophobic patterns - band pattern, axial pattern and random pattern - are discussed to reduce the damage to the lipid membrane. Both the free energy analysis and simulation studies show that the axial pattern and the random pattern can both minimize the variations in free energy with correspondingly smaller adverse effects on membrane function. These results suggest that the axial pattern or random pattern nanoprobe generates a mild interaction with the biological membrane, which should be considered when designing nondestructive nanoscale structures.

High‐Aspect‐Ratio Nanostructured Surfaces as Biological Metamaterials

“…In the latter case, the membrane reforms neatly around the nanopillar. Disruption could be further decreased by patterning either axially orientated, alternating stripes, or randomly patterned hydrophilic and hydrophobic ligands on the nanopillar . While only applied to a single nanostructure, for those interested in promoting membrane penetration, this result subtly suggests that patterned surface chemistries (achieved perhaps by using self‐assembly onto microfabricated layers) are a possible route to improving the likelihood of spontaneous penetration, an idea supported experimentally by the biomimetic probe work of Almquist and Melosh …”

Ligands influence a carbon nanotube penetration through a lipid bilayer

“…When the CNTs are in the membrane, their ligands attract the hydrophilic heads and lead to hydrophilic holes around the CNTs, Fig. 2a(4), which is observed in the previous research in nanoprobes (Liu et al 2013a).…”

“…4) around the hydrophobic CNT, but a slight ''T-junction'' is formed, Fig. 9(4), which is also observed in hydrophobic nanoprobes (Liu et al 2013a). The hydrophobic pattern has a higher penetration capacity, which suggests that hydrophobic ligands would be a better choice for the penetration of CNTs.…”

“…Ligand hydrophilicity and hydrophobicity Hydrophilicity/hydrophobicity of nanostructures have been studied by some researchers (Liu et al 2013a;Van Lehn and Alexander-Katz 2011). Here we ignore the hydrophilicity/hydrophobicity of the CNTs, but focus on the hydrophilicity/hydrophobicity of the ligands.…”

“…(Kraszewski et al 2012) Their data proved that short nanotubes could passively penetrate the bilayer. Our previous work analyzed the interaction between a nanoprobe and a lipid bilayer, especially how the surface property of a nanoprobe affected the interface (Liu et al 2013a). We found that a hydrophilic nanoprobe generated a hydrophilic hole, while a hydrophobic probe leaded to a ''T-junction'' scenario when penetrating a membrane.…”