Researchers Develop World’s First Glucose Saliva Test for Diabetes

University of Newcastle researchers in Australia have developed a saliva test to evaluate glucose levels in diabetic patients. The test involves the use of testing strips that contain a glucose biosensor with electronic elements in the test’s transistor, like inks, that allow for mass printing of the test strips at low cost.

Currently, diabetic patients who monitor their blood sugar levels daily have to draw a blood sample by pricking their finger with a lancet. This can be a painful process, which can lead to patients reducing the number of tests they take.

However, as a needle-free test, the saliva test offers a painless and non-invasive way to monitor sugar levels, which could significantly help with compliance.

Since the electronic materials in the glucose biosensor are inks, the new test can be printed using conventional printers at a reduced cost.

The test is the world’s first needle-free test and could revolutionize glucose monitoring. Over 460 million people around the world live with diabetes.

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Biosensor Technology

The saliva test contains a glucose biosensor coated with the enzyme glucose oxidase and an electronic transistor. When the biosensor interacts with saliva, a reaction occurs that generates an electrical current. This current can be detected and measured to reveal highly accurate glucose levels. The results can be delivered via a smartphone app and the data is stored in the cloud.

The sensor is comparable to the size of a stick of chewing gum but is considerably thinner, allowing for powerful detection of substances in saliva in minute concentrations. The user simply licks the strip and inserts it into a glucose monitor.

“With this highly sensitive platform, we can now detect glucose at the levels found in saliva, for the first time,” said Professor Paul Dastoor, physicist at the University of Newcastle and lead researcher on the project, in a news release from Newcastle.

Professor Dastoor says the inspiration for the device came in part from his wife, who as a primary school teacher, helped young children to monitor their blood glucose levels.

“It’s a heartbreaking scenario when the lunch bell rings and everyone runs to the playground, bar an unfortunate few who stay back to surrender their finger for blood testing at every meal time,” Professor Dastoor said.

“Our vision was to create a world where no one needs to bleed in order to eat.”

Creating the testing device was a challenge as saliva glucose concentrations are 100 times lower than in blood. Saliva also contains a host of other substances which complicates things.

The researchers designed the sensor in the test to be significantly thin and sensitive.

The research group built a commercial-scale production facility in their lab at Newcastle. The campus factory is a shared facility that performs “functional printing” where printers are used for producing printed electronic or “functional” devices.

Now the team is working with a commercial partner and grant recipient — GBS, on a larger, world-class purpose-built manufacturing facility. Construction on the facility, which has received $6.3 million in funding under the Medical Products priority of the Australian Government’s Modern Manufacturing Initiative, will begin this year, with the first devices expected to roll off the production line by 2023.

Professor Dastoor says the biosensor is a platform technology and as such, could be expanded for the detection of a variety of substances associated with various diseases.

Functional Printing

This includes COVID-19, and the research team is partnering with the Wyss Institute for Biologically Inspired Engineering at Harvard University to help develop the sensor platform as a non-invasive COVID test.

And with functional printing of the strips, Professor Dastoor’s team will “marry the old and the new,” using conventional printers combined with proprietary electronic inks, allowing for low-cost production of advanced materials.

“What we’ve been able to do for the first time is combine printed electronics with biological sensing. That means we’re able to detect molecules like glucose, using sensors we can print hundreds of millions of, using really low-cost printing equipment,” Professor Dastoor said.

He also says functional printing could revive the disappearing traditional print manufacturing industry.

“Disruption in the traditional print industry has left a great deal of useful equipment stranded. Functional printing of electronic devices such as the saliva glucose biosensor is an opportunity to recommission this idle equipment, resuscitating onshore manufacturing industries and creating jobs for skilled workers,” Professor Dastoor said.