Researchers have been working for more than a decade to bring lab-on-a-chip to market. At first it was to supply the military with small, disposable devices that would detect chemical and biological weapons. Today, it is focused more on clinical diagnostics and at-home testing. At Sandia National Laboratory, biomedical engineers are putting the finishing touches on a five-pound desktop machine that will examine saliva to identify patients with gum disease.

In the process, antibodies associated with gum disease are tagged with fluorescent dye and mixed with saliva. Bacteria and organisms responsible for gum disease in the sample (also known as biomarkers) attach to the fluorescent antibody. The mixture is injected into a microchip and an applied electric field forces the sample to flow through a microchannel two to five centimeters long, tens of microns deep, and a few hundred microns wide.

As the sample moves through the channel, cast-in-place porous polymers in the microchannel sort molecules based on sizes and electric charges. A photomultiplier detects biomarkers in the sample. If it emits enough fluorescence — indicating biomarkers are above a certain level — a doctor could conclude that the patient has or will get gum disease, and preventive or therapeutic care could begin. Researchers are planning a version that will also check for heart disease.