Departament d'Enginyeria Quimica, Universitat Rovira i Virgili 26 Avenue dels Paisos Catalans, 43007 Tarragona, Spain.
ACS Nano. 2010 Sep 28;4(9):5293-300. doi: 10.1021/nn1016549.
Great efficiency to penetrate into living cells is attributed to carbon nanotubes due to a number of direct and indirect observations of carbon nanotubes inside the cells. However, a direct evidence of physical translocation of nanotubes through phospholipid bilayers and the exact microscopic mechanism of their penetration into cells are still lacking. In order to test one of the inferred translocation mechanisms, namely the spontaneous piercing through the membrane induced only by thermal motion, we calculate the energy cost associated with the insertion of a carbon nanotube into a model phospholipid bilayer using the single-chain mean field theory, which is particularly suitable for the accurate measurements of equilibrium free energies. We find that the energy cost of the bilayer rupture is quite high compared to that of the energy of thermal motion. This conclusion may indirectly support other energy-dependent translocation mechanisms, such as, for example, endocytosis.
由于许多观察到的碳纳米管直接进入细胞的现象，碳纳米管能够高效地穿透活细胞。然而，碳纳米管通过磷脂双分子层的物理转移的直接证据，以及它们进入细胞的确切微观机制仍然缺乏。为了测试推断的转移机制之一，即仅由热运动引起的自发刺穿细胞膜，我们使用单链平均场理论计算了将碳纳米管插入模型磷脂双层所需的能量成本，这特别适用于平衡自由能的精确测量。我们发现，与热运动能量相比，双层破裂的能量成本相当高。这一结论可能间接地支持其他依赖能量的转移机制，例如，例如，内吞作用。
