National Laboratory of Solid State Microstructure, Department of Physics , Nanjing University , Nanjing 210093 , China.
Departament d'Enginyeria Quimica , Universitat Rovira i Virgili , 26 Av. dels Paisos Catalans , 43007 Tarragona , Spain.
ACS Nano. 2018 Dec 26;12(12):12042-12049. doi: 10.1021/acsnano.8b04657. Epub 2018 Nov 27.
Increasing awareness of bioeffects and toxicity of nanomaterials interacting with cells puts in focus the mechanisms by which nanomaterials can cross lipid membranes. Apart from well-discussed energy-dependent endocytosis for large objects and passive diffusion through membranes by solute molecules, other translocation mechanisms based on physical principles can exist. We show the importance of membrane tension on the translocation through lipid bilayers of ultrashort carbon nanotubes (USCNTs). By using a combination of a microfluidic setup and single chain mean field (SCMF) theory, we observed that, under membrane tension, USCNT inserted into a lipid bilayer may spontaneously nucleate an unstable local pore, allowing it to escape from the bilayer. We demonstrated that stretching of the membrane is essential for triggering this mechanism of translocation, and no translocation is observed at low membrane tension. For this purpose, a quantitative analysis of the kinetic pathway associated with USCNT translocation induced by tension was performed in a specially designed microfluidic device, simultaneously combining optical fluorescence microscopy and electrophysiological measurements. An important outcome of these findings is the identification of the way to control the nanomaterial translocation through the lipid bilayer by membrane tension that can be useful in many practical applications.
提高对与细胞相互作用的纳米材料的生物效应和毒性的认识，使人们关注纳米材料能够穿过脂质膜的机制。除了大家讨论较多的大物体依赖能量的内吞作用和溶质分子通过膜的被动扩散之外，还可能存在基于物理原理的其他转位机制。我们展示了膜张力对超短碳纳米管（USCNT）穿过脂质双层的转位的重要性。通过使用微流控装置和单链平均场（SCMF）理论的组合，我们观察到，在膜张力下，插入脂质双层的 USCNT 可能自发地引发不稳定的局部孔，从而使其从双层中逃脱。我们证明了膜的拉伸对于触发这种转位机制是必不可少的，并且在低膜张力下观察不到转位。为此，在专门设计的微流控装置中，通过光学荧光显微镜和电生理测量同时进行，对由张力引起的 USCNT 转位相关的动力学途径进行了定量分析。这些发现的一个重要结果是确定了通过膜张力控制纳米材料穿过脂质双层转位的方法，这在许多实际应用中可能很有用。
