Elektrokardıyogram ıçın gümüş nanotel / kıtosan nanokompozıt kuru elektrotlar.

Nanocomposites of chitosan and silver nanowires (Ag NWs) were fabricated and their mechanical, thermal, electrical and antibacterial properties were investigated. A simple solvent casting method was used for the fabrication of nanocomposites with different Ag NW loadings ranging from 1 wt.% to 40 wt.%. Nanowires showed excellent dispersion in chitosan matrix. Antibacterial properties of the Ag NW/ chitosan nanocomposites were investigated against different bacteria strains of American type culture Collection (ATCC) using conventional microbiological methods. Prepared nanocomposites were found to have high antibacterial affect against Staphylococcus aureus, (ATCC #25923), Escherichia coli (ATCC#25922), Bacillus cereus (ATCC#14603) and Candida albicans (ATCC #90028) strains. Following the demonstration of antibacterial activity, fabricated nanocomposites were used as in-vitro electrocardiogram (ECG) electrodes. ECG measurement results showed that higher nanowire loadings within the nanocomposites have better performance in terms of recording useful ECG signals. Results presented herein showed that the Ag NW/ chitosan nanocomposites have a very high potential to be used as dry electrodes for ECG and offers simple and easy fabrication.Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Micro and Nanotechnology

MEMS cihazlarının koklear implant uygulamaları için esnek alt taban üzerine entegrasyonu.

This master thesis is a result of multidisciplinary research bringing together concepts in electronics engineering, implant technologies, materials science, microfabrication, and device physics. Advancements in healthcare technology and in-vivo implants, electronic devices implemented on flexible substrates are highly demanded in the near future. In order to create a physically flexible device which consists of rigid sub-systems serving distinct purposes and made up of varying types of materials, we need reliable and durable integration methods for each sub-system. Moreover, the connection of these subsystems on a flexible substrate is a new subject that requires development. Furthermore, developed system has to be implantable and biocompatible. Under these concerns, the aim of this master thesis is to develop physically flexible, implantable and biocompatible system by the application of new methods to integrate rigid components to flexible substrate. Rigid components can be micro electromechanical system (MEMS) based sensors chips and CMOS electronics. Since advancement in semiconductor technology requires multichip integration and trending 3D integration techniques, through silicon via technology is utilized in this thesis to solve multichip MEMS integration challenges. Flexible substrate which houses the overall system is a polymeric and biocompatible material for this study. The thesis starts by introducing the subject by giving the motivation of the study and the literature review of the field. Next, the methods and the applications of the study will be given in two main fabrication chapters. Development of a wafer level, void free TSV fabrication process flow was developed. TSV structures with 100 µm diameter and 350 µm depth were copper filled with via sealing and bottom-up electroplating process which is a two-step technique. Fabrication of parylene flexible substrate specifically designed to designate MEMS piezoelectric cantilever chips was presented. Four-point Kelvin measurement tests explained that yields 0.8 mΩ average TSV resistance on fabricated TSVs and feasibility study of TSV integration to MEMS piezoelectric resonator devices has been presented in the results and discussion chapter. Then, Finally, the conclusions and the future work are explained.Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Micro and Nanotechnology

Fabrication and Feasibility of Through Silicon Via for 3D MEMS Resonator Integration

In this study, development of a wafer level, void free TSV fabrication process flow and feasibility study of TSV integration to MEMS piezoelectric resonator devices have been presented. TSV structures with 100 mu m diameter and 350 mu m depth were copper filled with via sealing and bottom-up electroplating process which is a two-step technique. Four-point Kelvin measurements showed 0.8 m Omega TSV resistance on fabricated TSVs. Furthermore, TSV frames were epoxy bonded to MEMS acoustic transducers, which showed 90% to the resonator signal from the TSV