Intracellular trafficking of carbon nanotubes by confocal laser scanning microscopy

We describe a simple methodology to study the interactions between ammonium-functionalized single-walled carbon nanotubes (SWNT-NH3+s), free of fluorescent labels, with mammalian cells. We exploit the intrinsic UV-vis luminescence of these nanostructures by using confocal laser scanning microscopy (CLSM) with established and widely used optics. Tracking the luminescence signal of SWNT-NH3+s with CLSM demonstrates that these nanotubes can traffick intracellularly, and elucidates in 3D their perinuclear localization. Imaging of SWNT-NH3+ luminescence is a powerful tool that allows for facile and widespread study of the interactions between nanotubes and living tissues in vitro and in vivo. Recently, the development of carbon nanotubes (CNTs) as delivery systems for nucleic acids, proteins, and drug mmolecules into mammalian cells and living tissues has attracted much attention. Previous reports have also studied the toxicological impact and safety profile of carbon nanomaterials following cellular uptake, indicating that a higher degree of CNT functionalization leads to a dramatic reduction in toxic effects.