Siao-Jie Yan

The Characteristic Analysis of IGZO/Al pH Sensor and Glucose Biosensor in Static and Dynamic Measurements

In this paper, the pH sensor and glucose biosensor were integrated with microfluidic framework, and the sensing characteristics under the dynamic conditions, i.e., solution under flowing condition, were investigated. The indium-gallium-zinc oxide (IGZO), as a sensing membrane, was deposited on aluminum electrodes/polyethylene terephthalate substrate. Then, the screen-printed technology was used to accomplish the encapsulation of sensor. The glucose biosensor based on enzyme needed an extra glucose sensing membrane, which was composed of glucose oxidase (GOx) and nafion. The glucose sensing membrane was dropped on the IGZO/Al sensing membrane. According to the experimental results, the optimal sensing characteristics of pH sensor and glucose biosensor under the dynamic conditions were better than those under the static condition (solution without flowing). The optimal average sensitivity and linearity were 56.857 mV/pH and 0.997 at 25 μL/min flow rate, respectively (in pH sensor), and 7.255 mV/mM and 0.994 at 20 μL/min flow rate, respectively (in glucose biosensor). Furthermore, the hysteresis effect and drift effect were researched for pH sensor, and the electrochemical impedance spectroscopy was used to demonstrate whether the IGZO/Al sensing membrane had been modified by GOx and nafion and it was found that the additions of GOx and nafion had increased the electron transfer resistance (Ret).

Fabrication of Flexible Arrayed Lactate Biosensor Based on Immobilizing LDH-NAD+ on NiO Film Modified by GO and MBs

We proposed the flexible arrayed lactate biosensor based on immobilizing l-lactate dehydrogenase (LDH) and nicotinamide adenine dinucleotide (NAD+) on nickel oxide (NiO) film, and which the average sensitivity could be enhanced by using graphene oxide (GO) and magnetic beads (MBs). By using GO and MBs, it exhibits excellent sensitivity (45.397 mV/mM) with a linearity of 0.992 in a range of 0.2 mM to 3 mM. According to the results of electrochemical impedance spectroscopy (EIS), the electron transfer resistance of LDH-NAD+-MBs/GPTS/GO/NiO film was smaller than those of LDH-NAD+/GPTS/GO/NiO film and LDH-NAD+/GPTS/NiO film, and it presented the outstanding electron transfer ability. After that, the limit of detection, anti-interference effect and bending test were also investigated.

Investigation of Sensitivities and Drift Effects of the Arrayed Flexible Chloride Sensor Based on RuO2/GO at Different Temperatures

We investigate the temperature effect on sensing characteristics and drift effect of an arrayed flexible ruthenium dioxide (RuO2)/graphene oxide (GO) chloride sensor at different solution temperatures between 10 °C and 50 °C. The average sensor sensitivities according to our experimental results were 28.2 ± 1.4 mV/pCl (10 °C), 42.5 ± 2.0 mV/pCl (20 °C), 47.1 ± 1.8 mV/pCl (30 °C), 54.1 ± 2.01 mV/pCl (40 °C) and 46.6 ± 2.1 mV/pCl (50 °C). We found the drift effects of an arrayed flexible RuO2/GO chloride sensor in a 1 M NaCl solution to be between 8.2 mV/h and 2.5 mV/h with solution temperatures from 10 °C to 50 °C.

Sensing Characteristic of Arrayed Flexible Indium Gallium Zinc Oxide Lactate Biosensor Modified by Magnetic Beads

In this paper, we proposed an arrayed flexible lactate biosensor, and indium gallium zinc oxide (IGZO) was used as the sensing film. The screen-printed technology was used to miniaturize the reference electrode and conductive wires. Lactate dehydrogenase and nicotinamide adenine dinucleotide were used to deposit enzyme membrane on IGZO sensing film to catalyze lactate. In the measurement, the arrayed flexible IGZO lactate biosensor was immersed in the lactate solutions, which concentrations were 0.2, 0.7, 1.3, 2, and 3 mM, respectively. The average sensitivity and linearity of lactate biosensor were 114.900 mV/decade and 0.948, respectively.

Analysis of non-ideal effects and electrochemical impedance spectroscopy of arrayed flexible NiO-based pH sensor

In this study, nickel oxide (NiO) was used as sensing film of arrayed flexible NiO-based pH sensor, which could reach high sensitivity (63.376 mV/pH) by potentiometric measurement system. Non-ideal effects of the sensor, such as drift and hysteresis effects, were investigated. Drift rate in pH 7 was 3.436 mV/hr, and hysteresis voltages in loops of pH 7 → pH 3 → pH 7 → pH 11 → pH 7 and pH 7 → pH 11 → pH 7 → pH 3 → pH 7 were respectively 4.496 mV and 1.817 mV. Moreover, sensing mechanism was characterized by electrochemical impedance spectroscopy.