Single-walled carbon nanotube-based molecular probes, imaging agents, and optical biosensors continue to garner interest as investigational tools and clinical devices due to their stable photoluminescence in the tissue-penetrating near-infrared (NIR) region and environmental sensitivity mediated by a change in redox, pH, dielectric, and electrostatic charges. Surface chemistry modulation of nanotubes plays a critical role in determining stability and interaction with biological system both in vitro and in vivo. We synthesized a small library of helical polycarbodiimide polymers that non-covalently suspended the single-walled carbon nanotubes in aqueous media. The polymer-nanotube assembly is driven by π-π interactions between the graphitic carbon nanotube surface and the phenyl side groups on the polymers. Using these materials, we found that the functional moieties on the polymer influenced the uptake and subsequent subcellular localization of carbon nanotubes in cancer cells and facilitated to target cell nucleus or cytoplasm. We delivered carbon nanotubes to cell nucleus via cloaking in a guanidinium-functionalized polycarbodiimide. We found that the nuclear translocation of the nanotubes was mediated by the import receptor importin β without the aid of importin α and not by the more common importin α/β pathway that is utilized by majority of the proteins with classical nuclear localization sequences. Additionally, the nanotube photoluminescence exhibited distinct spectral response upon entry to the nucleus, functioning as a reporter which may be used as a research tool for the study of nucleus-related pathologies.

Polycarbodiimide cloaking modulates the carbon nanotube delivery into cancer cells

254th National Meeting (2017)

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