Loading...
Nano-clay based flexible and implantable bioelectrodes for human body neurostimulation: fabrication and characterization
Alani, Zaid Osama
Alani, Zaid Osama
Description
A Master of Science thesis in Biomedical Engineering by Zaid Osama Alani entitled, “Nano-clay based flexible and implantable bioelectrodes for human body neurostimulation: fabrication and characterization”, submitted in May 2024. Thesis advisor is Dr. Amani Al-Othman and thesis co-advisor is Dr. Hasan Al-Nashash. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).
Abstract
This thesis explores the development and characterization of nano-clay based flexible and implantable bioelectrodes for human body neurostimulation, focusing on optimizing their biocompatibility, stability, and electrochemical attributes. Key materials such as silicone, nano-clay, glycerol, polyethylene glycol (PEG), and isoalcohol were employed to create a variety of composite samples. The primary objective is to ascertain how different material combinations influenced the electrodes' properties, aligning them with requirements for successful application in neurostimulation devices. Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltammetry (CV) provides comprehensive insights into the electrodes' performance. The EIS results indicated that varying the glycerol and PEG content affected the electrodes' bulk impedance, conductivity, and charge storage capacity. For instance, a sample with a 50% silicone, 20% glycerol, and 30% nano-clay composition showed a bulk impedance of 5.47 kΩ and conductivity of 2.33×10⁻⁵ S/cm, significantly outperforming a similar sample with PEG, which exhibited a higher bulk impedance of 38 kΩ and lower conductivity of 3.35×10⁻⁶ S/cm. These findings underscore the role of glycerol in enhancing electrochemical properties conducive to effective neural interface operations. Mechanical testing highlighted that the incorporation of nano-clay generally increased stiffness, whereas glycerol and PEG improved flexibility and conductivity. The optimal formulations displayed mechanical properties that were well-matched to the compliance required for integration with soft tissues, enhancing the potential for chronic implantation without adverse tissue reactions. Long-term immersion tests further demonstrated the electrodes' robustness, showing minimal degradation of electrochemical properties over extended periods, thus confirming their suitability for long-term neurostimulation and other clinical applications. The study successfully demonstrated that nano-clay based bioelectrodes could achieve excellent electrochemical performance and mechanical compliance, suggesting their potential for advanced biomedical applications. These findings pave the way for further research aimed at refining the bioelectrode technology for enhanced therapeutic outcomes in neurostimulation and other medical interventions.