This technology provides a method of continuous glucose sensing using nano-structured amorphous indium gallium oxide (IGZO) field effect transistors (FETs). IGZO-FETs can be processed at low temperatures that are compatible with flexible transparent substrates. A nano-structured IGZO has been applied to the surface of the FET and functionalized with active glucose oxidase enzyme. The nano-structured amorphous IGZO is arranged in way to increase surface area, leading to higher sensitivity and selectivity to detect glucose within a normal, physiologically relevant range. Glucose is biocatalytically oxidized in the presence of glucose oxidase, allowing the functionalized FET to selectively detect glucose only and minimize interference from other compounds likely to be present in blood or tears. FETs can be a simple and cost-effective approach to glucose sensing that can detect glucose levels in the relevant range of medical examination for diabetes diagnostics.
Features & Benefits
Background of Invention
In the U.S. more than 1 million people have been diagnosed with type I diabetes mellitus. Extremes in blood glucose levels can lead to major health issues. High blood sugar (hyperglycemia) can cause complications such as vascular and kidney disease, while low blood sugar (hypoglycemia) can lead to seizures and loss of consciousness. Glucose sensors are a critical component of an artificial pancreas and have been extensively studied during the past several decades. For these applications the sensors need to be sensitive and reliable while measuring glucose concentrations over the normal physiological range. Common amperometric sensors include an Ag/AgCl counter/reference electrode and a platinum working electrode which is coated with a sensing enzyme and a permselective membrane. The disadvantage of the enzyme-based amperometric sensor is the high oxidation potential required on the sensing electrodes for glucose sensing; putting the detection range outside the physiological range. Amorphous indium gallium oxide (IGZO) field effect transistors (FETs) are a promising technology that has recently increased interest in areas including temperature, light sensing, and chemical and biochemical sensors.
Figure 4: (a) Time course of S/D current change for varying concentrations of glucose as measured using IGZO FET functionalized with GOx. Arrow 1 and 2 indicates addition of 0.13 mM acetaminophen and ascorbic acid, respectively. (b) S/D current change vs. logarithmic glucose concentrations.
Provisional patent application filed; available for licensing