2007 Volume 5 Pages 23-28
We have prepared extremely small functionalized nanoparticles (NPs) and showed that they could be introduced into living cells without modification (e.g. cationic coating) to enhance endocytic internalization. However, the internalization depended on physical adsorption of the particles on the cell surfaces, and therefore the internalization process was nonselective. Here, we prepared NPs conjugated with folic acid and a coumarin fluorophore so that the NPs (d = 2.6 nm) would be recognized by folate receptors on the cell surface. The presence of the folic acid and coumarin on the surface of the NPs was confirmed by Fourier transform infrared spectroscopy. The modified NPs were internalized by human pharyngeal cancer cells (KB cells) after an incubation time that was short compared with the time required for internalization of NPs without folic acid. This result indicates that the folic acid receptor on the KB cell membrane recognized the folic acid-conjugated NPs. Cellular recognition of NPs may lead to the development of cell-specific delivery systems. [DOI: 10.1380/ejssnt.2007.23]
