The media is high on the cocainalyzer, which we covered back in February.
It’s newsworthy because current ID methods for cocaine aren’t so fast, or are easily tricked. But what makes this news really tremendous is just how adaptable this new analysis technology is. This method is based on “aptamers” — a DNA binding molecule that can be customized to find may other molecules of interest, quickly, without pre-purification:
The detector works by passing an electronic signal through a type of DNA molecule, called an aptamer, that binds with other specific molecules, in this case cocaine.
This particular type of aptamer, which is synthetic, is usually floppy. When it binds with cocaine, however, it stiffens up and assumes a structured, folded shape, which causes it to allow electrons to pass through it more readily.
The drug detector’s engine is a 1-millimeter square electrode that is coated with somewhere around 100 million of the cocaine-friendly molecules. After each test this electrode can be rinsed and reused with a loss in sensitivity of just 1 percent. That means an electrode could be used perhaps 100 times before it would have to be replaced. It also can be used immediately after washing, a key feature for a portable tester, Plaxco says. “We wash it with a cocaine-free buffer and it resets in seconds,” he said…
By using different aptamer DNA molecules that favor other substances, the same technology could be expanded to find other drugs, both the illicit type and the therapeutic variety whose levels must be closely monitored in patients.
“We’re monitoring a very specific binding-induced change in the DNA itself. And that’s why our sensor works straight in blood serum,” Plaxco said. “That’s the real advantage. Other people have built biosensors that are just as sensitive as ours. Other people have built biosensors using aptamers even, that are just as generalizable as ours. Ours has both of those attributes and it works in blood, and dirt, and food. That’s the huge advance.”