Design of robust closed-loop ultrasonic implant systems
Abstract/Contents
- Abstract
- Implantable medical devices for physiological monitoring and therapeutics are important tools for treating chronic diseases and restoring impaired body functions. Recent advances in wireless power and data transfer have driven the development of smaller, minimally invasive implants with real-time connectivity and new capabilities. In particular, ultrasound wireless power and communication has been successfully used for many proof-of-concept single implant sensors and stimulators. Next-generation therapies will need to precisely coordinate multiple implants combining sensing, stimulating, and processing to enable applications like bioelectronic medicine and brain-machine interfaces. In order for ultrasonic implant systems to support these applications, they will require more robust and scalable power and data transfer as well as closed-loop functionality to operate reliably in the body. In this work, we present approaches for building each aspect of a robust ultrasonic implant system. First, we discuss how to increase ultrasonic communication data rates using line-of-sight MIMO techniques. By taking advantage of the spatial degree of freedom, we show how to potentially scale the channel capacity with the number of implants. Using this concept, we demonstrate a 2x2 communication link with double the data rate of a conventional ultrasound link. Next, we propose an implant localization scheme using harmonic backscatter and demonstrate sub-millimeter accuracy. Using this location data with an ultrasound transducer array we can selectively and efficiently beamform power to implants. Finally, we describe the design of a closed-loop implantable drug delivery system, combining an electrochemical drug release mechanism with a custom CMOS chip. The implant includes power sensing and combining for more reliable power transfer as well as a potentiostat with a ±1.5 V stimulation range and ±100 uA readout range for programmable drug release. The techniques and systems presented in this work demonstrate how to build an ultrasonic implant platform for next-generation closed-loop medical applications.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2022; ©2022 |
| Publication date | 2022; 2022 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Wang, Max Li-Hua |
|---|---|
| Degree supervisor | Arbabian, Amin |
| Thesis advisor | Arbabian, Amin |
| Thesis advisor | Dahl, Jeremy J, 1976- |
| Thesis advisor | Murmann, Boris |
| Degree committee member | Dahl, Jeremy J, 1976- |
| Degree committee member | Murmann, Boris |
| Associated with | Stanford University, Department of Electrical Engineering |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Max Li-Hua Wang. |
|---|---|
| Note | Submitted to the Department of Electrical Engineering. |
| Thesis | Thesis Ph.D. Stanford University 2022. |
| Location | https://purl.stanford.edu/fn562zf5030 |
Access conditions
- Copyright
- © 2022 by Max Li-Hua Wang
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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