Nitric oxide (NO) detection is a critical issue for environmental safety and medical diagnosis due reasons with regard to the toxic properties for human body and metabolic index for respiratory disease, respectively. Development of gas sensor with high sensitivity is very important because the concentration of NO gas in the environment and respiratory tract is extremely low, therefore not readily detectable. The material with nanostructure can improve the sensitivity of sensor owning to surface effect and size effect. Herein, we developed a new type of gaseous nanosensor assembled by 34 nanowires of conducting polymer, PEDOT: PSS. The nanowires were fabricated by dip pen nanolithography (DPN) with the length of 55 um and diameter of 300 nm between golden wires. The NO gas measurement is based on chemiresistor based methods. The result of dynamic measurement of NO gas at 100 ppm shows repeatability and stability; the recovery time is 10.4 minutes. Moreover, the lowest concentration of NO gas in static measurement is 10ppm at 80 C, which also shows the ability sensing at low temperature.
This work demonstrates a method of electroplating nanostructured Pt, Ir, and Pt-Ir at room temperature. All the obtained samples have been characterized by SEM and XPS. By controlling the volume ratio of Pt to Ir electrolytes, Pt(100%)-Ir(0%), Pt(91.2%)-Ir(8.8%), Pt(81.3%)-Ir(18.7%), and Pt(12.4%)-Ir(87.6%) were formed on the surfaces. Besides, the nanostructure was formed with the help of vigorously hydrogen bubble generation. The results indicate that co-electrodeposition of nanostructured Pt-Ir films at room temperature can be achieved by manipulating the concentration of Ir electrolyte and the concentration of HCl.
Over the past decade, the development of non-enzymatic electrochemical biosensors had thriven at a considerable rate. Compared with the traditional enzymatic electrochemical biosensors, the non-enzymatic electrochemical biosensors have the advantages of higher sensitivity and stability. Recently, plenty of researches have devoted to synthesizing new materials, such as bimetallic nanoparticles, and also develop speci¯c nanostructures on the sensor surface to solve the problem of poisoning and increase the selectivity. This work develops two non-enzymatic glucose sensors that are based on nanostructured PtÀIr¯lms which were deposited by electrodeposition. Because of the relatively high deposition current density, bubbles produced vigorously on the working electrode surface. This phenomenon results in leaf-like nanostructure formed naturally on the surface of the working electrode and further increased the catalytic reaction area. Besides, as determined by the sampling analysis method that is developed herein, the presented PtÀIr sensors mitigate the current drifting problem which is easily observed when a constant potential is applied in an amperometric glucose detection. Furthermore, the presented PtÀIr sensors show high sensitivity and stability in 1X PBS (0.15 M NaCl) at 37 C in the glucose concentration range of 1À12 mM. Therefore, the presented non-enzymatic glucose sensors not only provide great potential in biomedical applications, such as homecare products, but can also be adapted for the biological application, such as continuous cell culture monitoring.
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