To alleviate the pain of diabetic patients in frequent blood glucose tests, Dr Yan Feng and his research team at the Department of Applied Physics developed an ultra-sensitive transistor-based biosensor that measures glucose concentration in saliva. Fabricated by using a glucose oxidase enzyme layer, the biosensor is sensitive only to glucose. It simply measures the glucose level by detecting the electric current in saliva. However, other biological elements in saliva such as dopamine, uric acid and ascorbic acid may interfere with the electric current and thus affect the glucose reading. To avoid such interference, bilayer films of polyaniline and nafion-graphene are placed between the top enzyme layer and gate electrode.
The biosensor can detect glucose level as low as 10-5 mmol/L, nearly a thousand times more sensitive than a conventional blood-glucose measuring device. The accuracy of the biosensor is proven using solutions with known glucose levels in rounds of repeated laboratory experiments. The research findings were published in Advanced Materials, a major academic journal in materials science.
Apart from being inexpensive to manufacture, the biosensor can be fabricated with flexible substrates to apply on curved and moving surfaces, including human skin and such wearable electronics as smart textiles and medical bandages. Details>>