There has been much recent interest in how nanotechnology will impact the field of medicine. Unfortunately, a number of promising nanostructured systems have turned out to be extremely toxic to humans, thus precluding their use in clinical applications and dashing hopes of an early success for the interdisciplinary field of nanobiotechnology.
Now a group of researchers at the University of Michigan Nanotechnology Institute for Medicine and Biological Sciences have devised a multifunctional nanoparticle platform comprising nanoparticles synthesized within dendrimers equipped with targeting molecules and dyes. These dendrimer nanoparticle systems are able to seek out and specifically bind to cancer cells.
Xiangyang Shi, Suhe Wang, James R. Baker Jr., and their colleagues have designed dendrimer nanoparticle systems that are stable, water soluble, and biocompatible. The researchers start out by synthesizing gold nanoparticles within amine-terminated dendrimers. Next, dye molecules and a targeting molecule, folic acid, are attached to the ends of the dendrimers. Finally, the remaining amine groups are acetylated to ensure that the complex particles do not bear any surface charges. This last step is especially important to ensure the biocompatibility of these systems and to prevent the nonspecific adhesion of other materials. Molecular dynamics simulations indicate that the folic acid attachments project out into the solvent and are readily available for binding to cells, whereas the dye molecules stay far removed from the metal nanoparticles and thus retain their bright fluorescence.