Spit on a strip? New biochip measures glucose using saliva

Diabetics soon may be able to test their glucose levels in their saliva, rather than pricking themselves to draw blood for testing.

Researchers at Brown University have created a biochip that can measure glucose levels in saliva with the same basic accuracy as blood tests, according to a paper published the scientific journal Nano Letters. It's a significant achievement considering that glucose concentrations in saliva are 100 times lower than those in blood.

Interestingly, detecting glucose is less about biological testing and more about subatomic particles and light. The new biochip is tiny, created with nanotechnology, and measures not fluids or chemical compounds, but light waves, according to a statement from Brown.

The biochip captures and collides photons and electrons inside a tiny groove. When they collide, the atoms emit light waves, which change intensity in the presence of glucose. It's that light intensity change that the Brown biochip actually measures to determine glucose concentrations in the saliva.

According to researchers, the biochip ultimately may be able to detect other isolates in human saliva, "from anthrax to other biological compounds." They're tweaking the biochip to try for other biomarkers, possibly even conducting multiple tests at the same time, with the same chip, researchers said. We reported on similar technology created by Rice University researcher John McDevitt in November.

It's an interesting new approach to diabetes testing. Just a few weeks ago, we reported on the creation of a contact lens by University of Washington researchers that could detect glucose levels in the fluid around the eye. And last summer, scientists at Northeastern University in Boston developed a nanosensor technology that could be injected under the skin, and read by passing a fluorescent light--attached to an iPhone--over the patch of sensors. The light intensity shows the patient's glucose levels.

To learn more:
- read the Brown University press release