Biochip tests saliva, not blood, for glucose

A biochip under development can measure glucose levels in human saliva, according to Brown University.

The sensor may one day eliminate the need to draw blood to check glucose levels for the 26 million people in the US living with diabetes.

Engineers at Brown University etched thousands of plasmonic interferometers onto a biochip the size of a fingernail. Surface plasmonics involves the interaction of electrons and light.

“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, assistant professor of engineering and lead author of the research paper on the study. The paper is published in the journal Nano Letters.

Glucose in human saliva is about 100 times less concentrated than in human blood.

The sensor could one day be used to accurately measure concentrations of glucose in water as low as 0.36 milligrams per deciliter.

“It could be possible to use these biochips to carry out the screening of multiple biomarkers for individual patients, all at once and in parallel, with unprecedented sensitivity,” Pacifici said.

The technique could be used to detect other chemicals or substances at once using just one chip, according to Brown University. Substances could include anthrax or biological compounds.

Blood glucose monitoring
Blood glucose monitoring is a crucial tool for managing diabetes and preventing complications from the disease. It helps patients determine how their diet and exercise affect their blood glucose levels, how illness and stress can affect blood sugar, and when their blood sugar is dangerously high or low.

Glucose testing requires drawing a drop of blood by finger prick. The drop of blood is then placed on a disposable test strip and tested using a small electronic device that measures glucose levels.

The frequency of testing depends on the type of diabetes and the management plan designed by the treating physician. Some patients may test their blood glucose levels 3 times a day or more. However, some patients may avoid regular testing due to the inconvenience and discomfort of drawing blood.

Source: Brown University, Mayo Clinic