Despite breakthrough diabetes research over the past century, people with diabetes still need to rely on obtaining blood samples to monitor their sugar levels. Daily glucose monitoring by tracking blood sugar levels is essential for managing both types 1 and 2 diabetes, however the current method – finger pricking – is invasive and can become burdensome with how often it needs to be done.
Since 2014, flash glucose monitoring was first introduced in Europe and this method uses a small, water-resistant sensor applied to the back of the upper arm. Compared with finger pricking monitor, this approach is more convenient but these sensors have known accuracy issues and some could fail altogether.
In the quest to eliminate invasive glucose monitoring for people with diabetes, research led by Wenyu Gao, a PhD student in the Department of Chemistry at the University of Waterloo, explores using saliva instead of blood to monitor glucose levels.
Working in the research lab of Professor Kam Tong Leung, Gao developed a prototype sensor that uses nanomaterials to test the sugar level in saliva samples. Even though saliva contains multiple components which need to be separated before testing, the accuracy of saliva-based sensor is over 95% when compared with the result of commercial blood glucose monitoring system.
Gao’s prototype saliva sensor uses copper nanomaterials which are anchored on a base strip made of graphene sheet. Graphene is an inexpensive carbon material that generally does not react with other compounds. “Graphene strips are thin and flexible just like paper, so you can deposit the materials on the top and it’s still flexible,” says Gao. “It’s a promising substrate in biosensors.”
The copper nanomaterials anchored to the graphene are present in three layers, in a core-shell structure made of Cu, Cu2O, and CuO. In this saliva sensor, glucose reacts with the Cu2O layer changing the number of electrons in the copper atom. This changes the electric current proportional to the amount of glucose present, which can then be measured as a blood sugar level.
Read the full article and learn about next steps for this saliva sensor on Waterloo News.