A novel functionalized multiwalled carbon nanotubes(f-MWNTs)-anticancer drug carriers were prepared by modifying carbon nanotubes with polyethylenimine (PEI), folic acid and quantum dots for targeting and imaging cancer cells. The functionalized MWNTs exhibited good aqueous solubility, biocompatibility and high targeting ability. Water-insoluble anticancer drug Paclitaxel (PTX) were further loaded onto the f-MWNTs mainly through noncovalent π–π stacking interaction. In vitro cytotoxicity studies of f-MWNTs–PTX complexes using MTT assay exhibited a significant enhancement in the cytotoxic capability, suggesting these targeting drug carriers could facilitate intracellular delivery of anticancer drug and improve drug antitumor activity. Therefore, the highly versatile multifunctional carbon nanotubes could potentially be used for advanced drug delivery in biomedical fields.

A novel functionaliztion of gold nanorods (GNRs) intracellular delivery system was prepared via electrostatically layer-by-layer assemblying, in which multilayer polyelectrolyte-coated GNRs were used as vector and antisense oligodeoxynucleotides (ASODNs) as therapeutic gene. The as-prepared positively charged GNRs were firstly modified with two successive polyelectrolyte layers of the negatively charged poly(sodium-4-styrenesulfonate) (PSS) and positively charged polyenthylenimine (PEI) in order to greatly improve the biocompatibility of these cetyltrimethylammonium bromide(CTAB)-coated GNRs and facilitate further biofunctionalization. The multilayered polyelectrolyte functionalized GNRs were characterized by UV-vis spectroscopy, transmission electron microscopy (TEM) and MTT assay. The polyelectrolytes-coated GNRs were then used as vector for ASODNs. Electrochemical impedance spectroscopy(EIS) was employed to confirm the formation of the GNRs-ASODNs conjugates through electrostatic interaction. Furthermore, cellular uptake and delivery efficiency of the GNRs-ASODNs conjugates as well as cellular apoptosis induced by the ASODNs transfected with gold nanorods were investigated by confocal microscopy and flow cytometry, exhibiting efficient intracellular delivery and improved antitumor activity of ASODNs by the polyelectrolytes-coated GNRs carriers.