A quick sniff of a nasal spray sends microscopic metal particles into the brain, where they target and destroy the damaging proteins of Alzheimer's disease. No Alzheimer's? No problem—the metal particles pass out of the body safely. Such is the promise of technology being developed by neuroscientist William Klein and nanotechnologist Vinayak Dravid of Northwestern University. The pair has invented a nanotech-based early-detection system that might one day deliver targeted treatments.

Klein and Dravid created an antibody—an immune molecule that detects specific chemical structures—that binds to a particle implicated in Alzheimer's. They linked the antibody to a nanoscale arrangement of iron oxide compounds, similar to rust, which can be seen with magnetic resonance imaging. The brain scan could detect the disease early on, so patients can start treatment sooner than they can today. “Once the chain reaction of negative events starts, it's like a lit fuse. You want to intervene as soon as possible,” Klein says.

Globs of beta-amyloid protein called plaques are a hallmark of Alzheimer's. But these days most neuroscientists agree that a tiny particle form of the same protein, called an oligomer, is the primary toxin in the illness. Eventually these smaller structures glom together to form plaques, but by then they have already damaged brain cells. The antibody created at Northwestern binds to the toxic oligomers and could one day deliver therapies to the brain or help clinicians evaluate how a patient is responding to a new medication.

So far the researchers have used the probe to distinguish between diseased and healthy human brain samples. The next step, slated for later this year, is to see if they can do the same in the brains of living mice. Already a nasal spray has successfully delivered the nanoparticles to a mouse's brain, most likely the same delivery method that would work for us humans.