Cell Behaviour and Cellular Uptake of Sic/Sio2 Nanowires in two different cell models

Nanomedicine is the application of nanotechnology to medicine and in particular to the diagnosis and treatment of diseases. Our goal is to develop a nanosystem, composed by 3C-SiC/SiO2 nanowires (NWs) and superparamegnetic Fe3O4 nanoparticles, functionalized with partially-fluorinated Tetraphenylporphyrins, for concurrent photodynamic therapy, hyperthermia and magnetic resonance imaging as deep cancer therapy. A549 and THP-1 cell lines were chosen as model to investigate both the cytoxicity and the uptake of the SiC/SiO2 NWs at increasing concentrations. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) were used to analyse the cellular uptake of NWs. Both MTT and Tripan Blue assay showed that NWs were slightly toxic only at the highest concentration tested. For the SEM and TEM analysis morphological and ultrastructural parameters were qualitatively and quantitatively considered and no significant alteration in either A549 or THP-1 cells occurred. Concerning the cell to nanowires interactions the SEM analysis showed cytoplasmic protrusions resulting in the contact of both a single NW and/or NWs agglomerates with the cell membrane. The TEM analysis showed the effective internalization of NWs in both A549 and THP-1 cells through two different mechanisms: pinocytosis and phagocytosis. In both cell lines the NWs close to the cell membrane proximity were uptake by short cytoplasmic processes and internalised into the cell as small vesicles with a pinocytosis mechanism. Moreover, THP-1 cells showed the presence of cytoplasmic processes which cover the NWs indicates an aspecific phagocytosis mechanism. Finally, regardless the internalisations mechanisms, big vesicles overcrowd of NWs were the result of their compartmentalisation within cells.