PEG-conjugated highly dispersive multifunctional magnetic multi-walled carbon nanotubes for cellular imaging

We report synthesis of a highly versatile multicomponent nanosystem by covalently decorating the surface of multiwalled carbon nanotubes (CNTs) by magnetite nanoparticles (Fe3O4), poly(ethylene glycol) (PEG), and fluorophore fluorescein isothiocyanate (FITC). The resulting Fe3O4-PEG-FITC-CNT nanosystem demonstrates high dispersion ability in an aqueous medium, magnetic responsiveness, and fluorescent capacity. Transmission electron microscopy images revealed that Fe3O4 nanoparticles were well anchored onto the surfaces of the CNT. In vitro time kinetic experiments using confocal microscopy demonstrated a higher uptake of the Fe3O4-PEG-FITC-CNT nanosystem localized at the perinuclear region of MCF7 cells compared to the free FITC. In addition, the CNT nanosystem demonstrated no evidence of toxicity on cell growth. Surface conjugation of multicomponents, combined with in vitro non-toxicity, enhanced cellular uptake for FITC and site specific targeting ability makes this fluorescent Fe3O4-PEG-FITC-CNT nanosystem an ideal candidate for bioimaging, both in vitro and in vivo.