Tiny Biochip Uses Saliva for Painless Diabetic Testing
Each plasmonic interferometer
CREDIT: Domenico Pacifici
No pain, no prick; just spit. For 26 million Americans with diabetes, checking blood sugar levels may become as easy and bloodless as dabbing saliva on a new biochip sensor.
That needle-free experience could come from a fingernail-size biochip capable of detecting glucose levels found in human saliva — levels about 100 times less concentrated than in the blood. That could save tomorrow's diabetes patients from having to check their blood sugar (glucose) levels by pricking their fingers.
The biochip has thousands of slits with two grooves on either side, known as plasmonic interferometers. Such a combination of slits and grooves channels light in a way that allows engineers at Brown University to detect certain chemical signatures based on changes in light intensity.
"This is proof of concept that plasmonic interferometers can be used to detect molecules in low concentrations, using a footprint that is ten times smaller than a human hair," said Domenico Pacifici, an engineer at Brown University and lead author of a paper published in the Dec. 26 online edition of the journal Nano Letters.
The biochip has only been tested on water containing glucose levels similar to those of saliva. But the next generation of sensors could detect many different biomarkers in saliva for individual patients, Pacifici said. He and his colleagues plan to build sensors tailored for glucose and other substances to test that concept.
One-third of Americans are projected to have diabetes by 2050, according to the Centers for Disease Control and Prevention. That looming medical crisis has spawned a flurry of possible diabetes monitoring devices, including one painless monitor connected to smartphones that could send data to family members and physicians.