Abstract: A method for measuring free radical comprises providing a sensor including a substrate and a conductive polymer layer, wherein the conductive polymer layer is configured on the substrate and made of conductive polymer; applying a liquid sample with free radical to the sensor so that the conductive polymer layer is covered with the liquid sample and the conductivity of the conductive polymer layer is lowered due to oxidation of the conductive polymer by free radical; and calculating the concentration of the free radical in the liquid sample based on the conductivity change rate of the conductive polymer before and after the liquid sample is applied to the conductive polymer. The present invention has advantages including low cost, small size, and ease of operation, which make it a good candidate for detecting hydroxyl radicals for oxidative stress studies.

Abstract: A viscosity measurement system, which is for measuring the viscosity of a fluid, comprises a transistor-type viscosity sensor, an electrical measurement unit, and a processing unit. The transistor-type viscosity sensor includes a semiconductor structure, a source terminal, and a drain terminal. The semiconductor structure includes a GaN layer and an AlGaN layer disposed on the GaN layer. The portion of the semiconductor structure that is between the source terminal and the drain terminal has a gate region, which has an exposed surface for being in contact with the fluid. The electrical measurement unit is in electrical connection with the source terminal and the drain terminal and for measuring an electronic signal of the semiconductor structure. The processing unit is coupled to the electrical measurement unit and for determining the viscosity of the fluid according to the electronic signal measured.

Abstract: A method for measuring free radical comprises providing a sensor including a substrate and a conductive polymer layer, wherein the conductive polymer layer is configured on the substrate and made of conductive polymer; applying a liquid sample with free radical to the sensor so that the conductive polymer layer is covered with the liquid sample and the conductivity of the conductive polymer layer is lowered due to oxidation of the conductive polymer by free radical; and calculating the concentration of the free radical in the liquid sample based on the conductivity change rate of the conductive polymer before and after the liquid sample is applied to the conductive polymer. The present invention has advantages including low cost, small size, and ease of operation, which make it a good candidate for detecting hydroxyl radicals for oxidative stress studies.

Abstract: A viscosity measurement system, which is for measuring the viscosity of a fluid, comprises a transistor-type viscosity sensor, an electrical measurement unit, and a processing unit. The transistor-type viscosity sensor includes a semiconductor structure, a source terminal, and a drain terminal. The semiconductor structure includes a GaN layer and an AlGaN layer disposed on the GaN layer. The portion of the semiconductor structure that is between the source terminal and the drain terminal has a gate region, which has an exposed surface for being in contact with the fluid. The electrical measurement unit is in electrical connection with the source terminal and the drain terminal and for measuring an electronic signal of the semiconductor structure. The processing unit is coupled to the electrical measurement unit and for determining the viscosity of the fluid according to the electronic signal measured.