That's right. Instantly.
Mad Cow disease prions are responsible for the transmission of bovine spongiform enchelalopathy to humans, causing new variant Creutzfeld-Jakob disease (nvCJD,) an incurable neurodegenerative disease, much like Alzheimer's plus Parkinson's, but kills people in just a couple years.
Right now, the "gold standard" of prion detection is to remove brain matter from an animal that is suspected to be infected (and is dead), inject that into another animal, wait for a long time, then kill the other animal and necropsy its brain. This can take years and (get this) only detects the prion infection 31% of the time.
That's a terrible assay.
The new nanotech assay technique developed by Harold Craighead and company use a "tuning fork" technique. A nano-sized tuning folk is coated with antibodies against the abnormal conformation of the prion protein.
For many other assays, the added weight of the antigen (in this case, the prion) would be enough to change the pitch of the nano-tuning fork when a vibration in the assay liquid sets the fork vibrating. However, because prions are so light, this doesn't work. The researchers used secondary antibodies and metal conjugates to increase the weight of the prions, thus the added weight changed the pitch of the vibrating fork by a detectable amount.
This assay would be invaluable to eliminate prion-infected cows from getting into our food chain, which caused the outbreak of new variant Creuzfeld-Jakob Disease in England a decade ago.
This assay could also test biomedical stocks, such as human growth hormone obtained from human cadavers (yep! that's where it comes from.) for nvCJD prions. Several doctors in France were just indicted for involuntary homicide for not being vigilant enough concerning cadaver HGH and thus infecting over 100 French children with nvCJD.
It's especially a concern when slaughterhouses are unscrupulous about slaughtering and processing "downer" cows, which are sick and possibly infected with mad cow prions.