Tong-Yu Wu

Research of Non-Ideal Effect and Dynamic Measurement of the Flexible-Arrayed Chlorine Ion Sensor

This paper investigated the sensing characteristics of a flexible-arrayed chlorine ion sensor, which was realized based on ruthenium oxide thin-film/polyethylene terephthalate substrate and fabricated by the screen-printed technology and the radio frequency sputtering technique. By the static measurement, the average sensitivity and the linearity of the chlorine ion sensor were 25.065 mV/pCl and 0.960 from 10-5 to 1 M sodium chloride (NaCl) solutions. This paper also investigated the non-ideal effect and dynamic microfluidic measurement for the flexible-arrayed chlorine ion sensor. The hysteresis potential of the flexible-arrayed chlorine ion sensor was 2.738 mV in the NaCl solutions with the cycle of 1 M → 10-3 M → 1 M → 10-1 M → 1 M. Besides, we measured the response potentials in different concentrations from 10-5 to 1 M NaCl solutions over 12 h, and the best drift rate of the chloride ion sensor was 0.454 mV/h in 10-2 M NaCl solution. By the dynamic measurement of the flexible-arrayed chlorine ion sensor, the average sensitivity and the linearity were 30.758 mV/pCl and 0.985 for the flow rate of 25 μL/min between 10-5 and 1 M NaCl solutions. Therefore, the average sensitivity and the linearity of the dynamic measurement were better than those of the static measurement for the flexible-arrayed chlorine ion sensor.

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.

The research of differential reference electrode arrayed flexible IGZO glucose biosensor based on microfluidic framework

This study used a fast, simple, and low-cost method to fabricate arrayed flexible glucose biosensor, and the glucose biosensor was integrated with microfluidic framework for investigating sensing characteristics of glucose biosensor at the dynamic conditions. The indium gallium zinc oxide (IGZO) was adopted as sensing membrane and it was deposited on aluminum electrodes / polyethylene terephthalate (PET) substrate by the radio frequency sputtering system. Then, we utilized screen-printed technology to accomplish miniaturization of glucose biosensor. Finally, the glucose sensing membrane was composed of glucose oxidase (GOx) and nafion, which was dropped on IGZO sensing membrane to complete glucose biosensor. According to the experimental results, we found that optimal sensing characteristics of arrayed flexible IGZO glucose biosensor at the dynamic conditions were better than at the static conditions. The optimal average sensitivity and linearity of the arrayed flexible IGZO glucose biosensor were 7.255 m...

A study of drift characteristic in arrayed flexible chlorine ion sensors with differential reference electrodes

The drift rate is change of voltage by time dependence, that is isothermal and fixed composition in the solution. In this study, we prepared arrayed flexible chlorine ion sensors which are fabricated by radio frequency sputtering technology and screen-printed technology to measure the drift in the different NaCl solutions, we obtained output voltage in variation concentrations from 10-5M to 1 M NaCl solutions over 12 hours, the drift rates of the chloride ion sensing devices are 1.122 mV/hr in 1 M NaCl solution, 1.192 mV/hr in 10-1 M NaCl solution, 2.869 mV/hr in 10-2 M NaCl solution, 1.529 mV/hr in 10-3M NaCl solution, 0.988 mV/hr in 10-4 M NaCl solution and 3.991 mV/hr in 10-5 M NaCl solution, respectively.

The research of the differential reference electrode arraved flexible IGZO pH sensor for different Ar/O 2 ratios

In this study, we used polyethylene terephthalate (PET) as substrate and we combined with screen-printed technology to achieve miniaturization of sensor. In order to avoid damaging for single sensing window, the sensor device had six sensing windows on polyethylene terephthalate (PET) substrate in this study. The six sensing windows could provide six measurement values, which could provide accurate measurement results. The sensing properties of indium gallium zinc oxide (IGZO) sensing membranes were changed by different sputtering parameters. Therefore, we changed Ar/O2 flow ratios of IGZO sensing membranes by the radio frequency sputtering system, which investigated about the sensing properties of differential reference electrode arrayed flexible IGZO pH sensor for different Ar/O2 flow ratios. Furthermore, we also researched on hysteresis effect and drift effect. The hysteresis experiments were carried out by two cycles of pH values, which were pH 7-11-7-3-7 and pH 7-3-7-11-7, respectively. The drift experiments were carried out by immersing IGZO sensor in pH3, pH7, pH11 buffer solutions for 12 hours, respectively. According to the experimental results, we found that Ar/O2 flow ratio of IGZO pH sensing membranes was set at 16/2 (in seem) by radio frequency sputtering system, which can have better performance. The sensitivity and linearity of the IGZO pH sensor were 54.737 mV/pH and 0.994 in Ar/O2 flow ambience of 16/2 (in sccm), respectively. The hysteresis values were 8.56 mV and 25.01 mV in cycles of pH 7-11-7-3-7 and pH 7-3-7-11-7 in Ar/O2 flow ambience of 16/2, respectively. The drift values were 1.06 mV/hr, 3.64 mV/hr, 6.04 mV/hr in pH3, pH7, pH11 buffer solutions from 5 to 12 hours in Ar/O2 flow ambience of 16/2, respectively. The experimental results demonstrated that IGZO sensing membrane was successfully applied to detect hydrogen ions.