A novel nanoprobe based on single-walled carbon nanotubes/photosensitizer for cancer cell imaging and therapy.

Nanomedicine and nanotechnology have provided an effective platform for integration of therapeutic and diagnostic agents. Single-walled carbon nanotubes (SWCNTs), a highly effective means of transporting cargos of various sizes and types across the cell membrane, are gradually playing a bigger and more important role in the field of nanomedicine. In this study, a novel nanoprobe based on SWCNTs and a fluorescent photosensitizer pyropheophorbide a (PPa), was developed and was used for cancer cell imaging and therapy in vitro. Phospholipids bearing polyehylene-glycol modified SWCNTs that can provide an interface for the conjugation of PPa were prepared by ultrasonication. The polyehylene-glycol modified SWCNTs were then conjugated with PPa by using covalent functionalization method to construct SWCNT-PEG-PPa nanoprobe. The functionalization of SWCNTs was evidenced by UV-vis absorption spectra and fluorescence spectra. Imaging of cancer cells with SWCNT-PEG-PPa nanoprobe was confirmed using two cancer cell lines via laser scanning confocal microscope tests, and killing of cancer cells with SWCNT-PEG-PPa was demonstrated using cytotoxicity tests. Moreover, the stability of SWCNT-PEG-PPa was further investigated. Our experiments indicated that the resulting SWCNT-PEG-PPa nanoprobe should have a great potential to be a potent candidate for cancer imaging and therapy.