Finding a few foes among billions of cellular friends

Beating cancer is all about early detection, and new research is another step forward in catching the disease early. A team of chemists is reporting a new way to detect just a handful of lurking tumor cells, which can be outnumbered a billion to one in the bloodstream by healthy cells. The researchers have constructed an ultrasensitive nanoprobe that can electrochemically sense as few as four circulating tumor cells, and it doesn't require any enzymes to produce a detectable signal.