Integration of Aluminium Interdigitated Electrodes with Zinc Oxide as Nanocomposite for Selectively Detect Alpha-Synuclein for Parkinson’s Disease Diagnosis

Parkinson’s disease is associated with motor and non-motor symptoms, mostly a motor symptom such as tremor is said to be an early indication for Parkinson’s disease development. Because of higher demands for faster and more precise diagnostic methods, it has sparked trends in the development of a biosensor for the diagnosis of Parkinson’s disease. Therefore, this study has fabricated a biosensor that is capable of detecting a specific Parkinson’s disease biomarker such as aggregation of alpha synuclein and this is crucial in reducing the burden of Parkinson’s disease and to be able to detect the disease at the earlier stage. Finding the inconsistent aggregation of alpha-synuclein is a promising method for the early detection of Parkinson’s disease. Using conventional photographic process, aluminium interdigitated electrodes (ALIDEs) have been fabricated and employed with sensitive electrochemical strategy for the specific detection of the Parkinson’s disease antigen (alpha synuclein). The microelectrode was developed based on aluminium electrode sputtered on silicon substrate. Further, zinc oxide (ZnO) was deposited by sputtering on the working electrode of the ALIDEs using a spin-coating method. The ZnO nanocomposite onto aluminium microelectrode surface provides a favourable platform for efficient loading of antibody via binding with antigen alpha synuclein. The effective loading of the biomolecules (antibody and antigen) on the ZnO nanocomposite surface modified aluminium microelectrode was observed by SEM, AFM and 3D Profilometer. The current flow for each concentration of alpha synuclein was observed at 7.5×10−6 A (10 fM), 8.8×10−6 A (100 fM), and 8.5×10−6 A (1 pM) respectively.

Design and Fabrication of a Fast Response Resistive-Type Humidity Sensor Using Polypyrrole (Ppy) Polymer Thin Film Structures

In this research article, an organic polymer based polypyrrole (Ppy) composite material has been synthesized and analyzed for the design and fabrication purposes of a fast-responsive, highly sensitive, and an economical resistive-type novel humidity detection sensor. This humidity sensor most suitably serves the purpose for industrial humidity (i.e., values ranging from low to high) detection applications. First, a polypyrrole composite material (a mixture of polypyrrole, polypyrrole-NiO, polypyrrole-CeO2, and polypyrrole-Nb2O5) has been synthesized by chemical oxidative polymerization method, and then is treated at various temperatures, i.e., 100, 150 and 200 °C, respectively. After this treatment, the synthesized samples were then characterized by using FTIR, SEM, and DTA/TGA techniques for analyzing humidity sensing properties. The polypyrrole samples with the best morphological structure and properties were then incorporated on interdigitated electrodes. For the fabrication purposes of this thin film structure, at first a few drops of polyvinyl alcohol (PVA) were placed over interdigitated electrodes (IDE) and then the synthesized polypyrrole composite was uniformly deposited in the form of a thin film over it. The plots show that this is a good resistive-type humidity detection device for the relative humidity range of 30% to 90%. The response and recovery times of this newly fabricated humidity sensor were reported to be the same as 128 s at room temperature. Additionally, the stability and the repeatability response behavior of this Ppy sensor were verified up to five cycles of multiple repetitions. This presents an excellent stability and repeatability performance of the sensor. Furthermore, the capacitances versus humidity response and recovery properties of the designed sensor were studied too. This illustrates an excellent capacitive verses humidity response and shows a linear and an active behavior. Lastly, the experimental result proves that polypyrrole composite thin film shows a reasonable best performance up to a temperature of 100 °C.