Imagine shrinking the beakers, eyedroppers, chemicals and heaters of a chemistry lab onto a little microchip that could dangle from a key chain. A growing number of companies and universities are claiming to have devised such marvels, ready to perform vital analyses from detecting biological warfare agents in a soldier’s bloodstream to identifying toxins in a tainted package of hamburger meat. Almost all the new devices are surprisingly far from portable, however. The sensor that examines a drop of blood or speck of beef might indeed fit in one’s hand, but the equipment required to actually move a fluidized sample through the chip’s tiny tubes often occupies a desktop or more.

Two research teams are overcoming that hurdle with creative microfluidics—the precise manipulation of microscopic droplets. By moving liquid molecules with air or electricity, the groups are integrating the equipment needed to sample, analyze and report, all on a fob the size of a USB flash drive. And although the current chips are being crafted by hand, the designs could ultimately be mass-produced. That prospect would finally bring labs-on-chips to the places they are most desirable—the developing world, the battlefield and the home—where they could quickly detect HIV, anthrax or Escherichia coli. A chip could even be implanted into a diabetic’s body to help monitor the person’s glucose and insulin levels.