Nanotechnologists Seek Biological Niches

In late August, behind closed doors at the austere National Academy of Sciences in Washington D.C., Samuel Stupp, a materials scientist and director of the Institute for BioNanotech-nology in Medicine at Northwestern University, showed a video clip for a committee evaluating the United States' billion-dollar-a-year National Nanotechnology Program. " Everyone was so quiet watching this movie. It was amazing, " recalls Clayton Teague, director of the National Nanotechnology Coordinating Office. The video's protagonist was a mouse with a damaged spinal cord that could only barely move using its front legs. Stupp's research involves engineering nanomolecules called peptide amphiphiles consisting of a hydrocarbon tail attached to a peptide into which is inserted amino-acid sequences that stimulate neu-rons to seek new connections with neighboring neurons. As the video clip revealed, two months after the injured mouse received an injection of Stupp's peptide amphiphiles, it was able to move (albeit awkwardly) using all four limbs. In bench tests, these same amphiphiles self-assemble into fibers with diameters in the nanometer-scale range, and the resulting nanofibers form neuron-friendly networks. Analyzing anatomical, molecular, and behavioral results from mice with spinal cord injury, Stupp and his collaborator , Northwestern neurology professor John A. Kessler, suspect that the amphiphiles, which form a gel when they self-assemble, prevent scar tissue from forming, thereby allowing initiation of the regenerative process in the injured spinal cord, a process that normally is blocked. Restoring a measure of mobility to a paralyzed animal, and the potential transfer of such a feat into human patients, is just one dramatic trajec-tory of the maturing and ever better funded face of biological nanotech-nology and its most touted offshoot— nanomedicine. Its practitioners have entered a new era rife with video evidence like Stupp's and Kessler's, patents for sensitive molecular detectors , and nanoparticle-based contrast agents for detecting, monitoring, and treating many illnesses, from breast cancer to cold sores. Nanotechnology pioneer, Rich-ard Smalley, won the Nobel Prize in Chemistry in 1996 for discovering buckyballs—the all-carbon, soccer-ball-shaped molecules that helped to push nanotechnology into high gear. Smalley, who died of leukemia in October at the age of 62, was one of the most vocal champions of the beneficial potential of nanotechnol-ogy, which he argued was destined to solve major societal and medical problems. In many of his speaking engagements since his cancer diagnosis in 1999, he asked rhetorically, " am I part of the last generation to die of …