Carbon Nanostructures Interaction with Giant Unilamellar Vesicles as a Cellular Model

Abstract

Carbon is a highly versatile element capable of forming a countless number of compounds among which exist different molecular allotropes. These allotropic forms are of great interest to the medical and technological industries. In particular, carbon nanotubes (CNTs) are of interest ought to their ability of penetrating the membrane of mammalian cells without causing any damage. The CNTs internalization is a controversial topic. It has been reported to occur by two different mechanisms: 1) An energy dependent mechanism, where the cell actively internalizes the CNTs via endocytosis and 2) A simple diffusion process, which happens without the active participation of the cell. Nevertheless, it is known very little about the physical and chemical interactions leading these processes.In the present work we analyze these interactions using giant unilamellar vesicles (GUVs) as a representative model of the basic structure of the cell. To assess the effect caused by the CNTs on the GUVs' membranes we implemented the electrodeformation method, which allows us to measure the mechanical properties of the membranes i.e. the bending stiffness and the stretching modulus. Using confocal microscopy we observed the interaction between the CNTs and the GUVs membranes.We found that the bending stiffness of the GUVs in presence of the CNTs incremented one order of magnitude and the elastic module augmented up to 50 times in comparison with the GUVs without CNTs. Confocal microscopy revealed the interaction of the CNTs with the membrane as well as the internalization of the nanotubes and the adhesion of vesicles in presence of CNTs.