Single-walled carbon nanotubes (SWCNTs) show promise in multiplexed bio-imaging and biosensing applications due to their photostable emission in the near infrared region, and the extreme optical sensitivity to the molecular environment. However, as produced, carbon nanotubes are insoluble and require surface functionalization prior to their uses in biomedical research. We non-covalently ‘cloaked’ carbon nanotubes with helical polycarbodiimide polymers to develop water soluble, biocompatible optical nanoprobes. The systematic modulation of the nanotube surface chemistry facilitates the development of new optical probes and sensors to study nano-bio interactions and allows the control of cellular delivery and sub-cellular localization of nanotubes in cancer cells.