Single-walled carbon nanotubes have a number of properties of interest for their development as sensors and molecular probes for use in biological media. They are inherently fluorescent in the near-infrared “tissue transparent window” and do not photobleach. Multiple, optically distinct nanotube species can be used for extensive multiplexing in a single sample.  To preserve these desirable qualities while solubilizing and functionalizing the hydrophobic nanotube, we have developed non-covalent wrappings consisting of helical polycarbodiimide polymers. The polymers can be modulated to control internalization and sub-cellular localization. Assessing the localization of carbon nanotubes is of the utmost importance for their further development in biological applications.