Whereas the amount of glucose available in saliva has traditionally been too small for detection, the Hong Kong scientists say their technology could detect quantities as small as 5g in an Olympic-size swimming pool.
The new glucose biosensor is fabricated with flexible substrates can perform in a variety of curved and moving surfaces, including human skin, smart textiles and medical bandages.
The researchers have coated polyaniline/nafion-graphene bilayer films between the top enzyme layer and gate electrode in their biosensor. The strong adhesion of this top layer to the glucose oxidase enzyme layer enables it to stabilise and perform well in glucose detection, they say.
“Our novel biosensor is selectively sensitive to glucose, accurate, flexible and low in cost,” said Yen Fang of the university’s department of applied physics.
“It shows a detection lower limit of 10-5 mmol/L, which is nearly 1,000 times more sensitive than the conventional device for measuring blood glucose.
“This means with this biosensor, as little as 5g of glucose in a standard swimming pool of 50m x 25m x 2 m can be detected.
“Accuracy of the biosensor has been ascertained through laboratory experiments with repeatable results using glucose solutions of known glucose levels,” said Associate Professor Yen.
Test chips could be produced at a commercial cost of HK$3-5 (US$0.40-0.65), which is comparable or even cheaper than products currently in use. They could be developed for use in clothing and wearable devices to also analyse glucose levels in sweat during exercise, the researchers said.