Design, Characterization, and Application of Intracranial Temperature Sensors Utilizing Zinc Oxide Thin-Film Transistors
Open Access
- Author:
- Deoras, Aneesh Sunil
- Area of Honors:
- Interdisciplinary in Electrical Engineering and Engineering Science
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Thomas Nelson Jackson, Thesis Supervisor
Bruce Gluckman, Thesis Honors Advisor
John Douglas Mitchell, Faculty Reader - Keywords:
- temperature
sensor
thin
film
transistor
zinc
oxide
neural
epilepsy - Abstract:
- Many neurological illnesses can be associated with focal changes in brain activity. Understanding how this activity develops may provide clinicians with advanced diagnostic and treatment tools for patients suffering from diseases like epilepsy and Parkinson’s. A frequently used metric for observing cerebrovascular fluctuations in brain tissue is temperature. Modern neural temperature sensors, although accurate, exhibit key deficiencies that include heat diffusion and high cost. The present work outlines the characterization of a novel implantable sensor that offers high precision, low heat diffusion, and low cost. The sensor, first presented in Kim et al, utilizes zinc oxide thin-film transistors (ZnO TFTs) printed on a flexible polyimide substrate. Before widespread dissemination to ongoing research, further work was required to confirm the sensors’ in vitro capabilities. This work took place on a transistor-level and a system-level. It was ultimately determined that a single ZnO TFT measures temperature to 0.002V/oC resolution in threshold voltage. It is shown that this difference is more influential in a single-ended sensor than a differential-ended one, but that the improved CMRR of a differential sensor is desirable when measuring in vivo temperatures. As a result, this paper recommends that future designs include single-ended amplification and static protection fabricated directly on the sensor. As part of the research, a monitoring structure was developed using a National Instruments USB-6211 DAQ and LabVIEW software. Included in this document is an overview of temperature sensing in neuroscience, guidelines for implantable device design, and an essential review of the ZnO TFT.