Browsing by Author "Yu, Zhanghao"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Magnetoelectric Bio-Implants Powered and Programmed by a Single Transmitter for Coordinated Multisite Stimulation
    (2022-01-14) Yu, Zhanghao; Yang, Kaiyuan
    Coordinated multisite biomedical stimulations have shown exciting promise in clinical therapies, such as applications in heart and spinal cord. To reduce infection risks, surgery complexity, and restrictions in subject mobility, implants need to be miniature and untethered. Moreover, for coordinated multisite stimulation, the system should flexibly deploy stimuli without leads, synchronize operation of all the implants, and freely scale the stimulation channel quantity. While significant progress has been made to develop bio-implants for multisite stimulation, existing approaches fail to simultaneously deliver these desired properties. In this thesis, we propose a hardware platform including mm-sized stimulating implants magnetoelectrically powered and individually programmed by a shared transmitter. The proposed novel single-transmitter, multiple-implant structure realizes more flexible stimuli deployment, easier synchronization of device operation, higher system efficiency, and improved scalability of stimulation channels. Magnetoelectric effects are leveraged to build the wireless power and downlink data links in this work, because of the good efficiency under receiver size constraints, low misalignment sensitivity and low tissue absorption. Magnetoelectric power transfer is capable of safely transmitting milliwatt power to devices placed several centimeters away from the transmitter coil, maintaining good efficiency with size constraints, tolerating 60-degree, 1.5-cm misalignment in angular and lateral movement, and supporting multiple receiver devices without increasing the transmitter power. The robust and efficient system-on-chip design enables the implants to operate reliably with a 2-V source amplitude change, tolerating a 40-mm transmitter-implant distance variation and 50-degree angular misalignment, 1.5-cm lateral misalignment at a 3-cm implantation depth. The implants achieve individual programming through physical unclonable function IDs and generates synchronized stimulation with a maximum efficiency of 90% and fully programmable stimulation patterns including amplitude, pulse width, shape, and delay. These key features bring great advantages to the proposed technique for clinical treatments.
  • Thumbnail Image
    Item
    Magnetoelectric Wireless Power and Data Links for Millimetric Bioelectronic Implants
    (2023-08-16) Yu, Zhanghao; Yang, Kaiyuan
    Implantable bioelectronics hold immense potential in transforming clinical therapies by enabling precise targeting of specific regions within the neural system, brain, and organs. To meet the demands for enhanced safety, simplified surgical procedures, minimal disruption to normal behaviors, and long-term operation, it is crucial for these bioelectronic implants to be wireless, battery-free, and highly miniaturized on a millimeter scale. Furthermore, these bio-implants should exhibit robust and efficient operation and deliver advanced bio-functionalities with utmost precision to ensure safe and effective therapies. Despite significant advancements in the development of millimeter-scale wireless battery-free bio-implants, several critical challenges remain. These challenges include establishing reliable, safe, and efficient wireless power transfer mechanisms, enabling bi-directional communication with high efficiency and bandwidth, integrating the implants into distributed wireless networks, and realizing effective and advanced biomedical functionalities. To address the challenges and drive advancements in the field of implantable bioelectronics, my research encompassed multidisciplinary studies integrating advanced integrated circuit (IC) design, hardware platform development, and exploration of magnetoelectric (ME) wireless technologies. This paper presents three key components of my research in this domain. First, this thesis presents wireless neural implants at the millimeter scale that exploit ME power and data transfer. The study demonstrates the superior advantages of the emerging magnetoelectric power transfer technique for millimeter-scale bio-implants, including high efficiency, robustness against misalignment, and low tissue absorption. The magnetoelectrically powered and programmable implants demonstrate reliable operation within the body, providing fully customizable stimulation. The effectiveness and significant advancements of these implants were extensively validated through successful minimally invasive endovascular stimulation of peripheral nerves in pigs. The second focus is the development of low-power ME backscatter communication for millimetric bio-implants. It introduces a first-of-its-kind ME backscatter technology and demonstrates the first bio-implant platform that exploits converse ME effects for uplink telemetry. The implant achieves data modulation by creatively manipulating the ME resonance frequency through a custom IC. Moreover, we presents an innovative pulse-width modulation technique to enhance the robustness and bandwidth of the ME backscatter communication. These innovations enable ME implants to receive power and engage in bidirectional communication using a single transducer, significantly facilitating their miniaturization and expanding their applicability for closed-loop operations. Lastly, this thesis showcases significant contributions in the realm of wireless networks comprising millimeter-sized bio-implants. Notably, a wireless coordinated multisite stimulation system is presented, where multiple implants are magnetoelectrically powered and individually programmed by a single transmitter. This system represents a significant step forward in the field, providing evident advantages, including improved system efficiency, a highly scalable and leadless architecture, flexible deployment options, and enhanced synchronization capabilities. Additionally, the thesis presents a distributed wireless network incorporating adaptive power transfer and innovative multi-access bidirectional telemetry techniques. These advancements effectively overcome the challenges associated with powering, communication, and the realization of precise and coordinated bio-functionalities within the bio-implant network.
  • Thumbnail Image
    Item
    A wireless millimetric magnetoelectric implant for the endovascular stimulation of peripheral nerves
    (Springer Nature, 2022) Chen, Joshua C.; Kan, Peter; Yu, Zhanghao; Alrashdan, Fatima; Garcia, Roberto; Singer, Amanda; Lai, C.S. Edwin; Avants, Ben; Crosby, Scott; Li, Zhongxi; Wang, Boshuo; Felicella, Michelle M.; Robledo, Ariadna; Peterchev, Angel V.; Goetz, Stefan M.; Hartgerink, Jeffrey D.; Sheth, Sunil A.; Yang, Kaiyuan; Robinson, Jacob T.; Bioengineering; Chemistry; Electrical and Computer Engineering; Applied Physics
    Implantable bioelectronic devices for the simulation of peripheral nerves could be used to treat disorders that are resistant to traditional pharmacological therapies. However, for many nerve targets, this requires invasive surgeries and the implantation of bulky devices (about a few centimetres in at least one dimension). Here we report the design and in vivo proof-of-concept testing of an endovascular wireless and battery-free millimetric implant for the stimulation of specific peripheral nerves that are difficult to reach via traditional surgeries. The device can be delivered through a percutaneous catheter and leverages magnetoelectric materials to receive data and power through tissue via a digitally programmable 1 mm × 0.8 mm system-on-a-chip. Implantation of the device directly on top of the sciatic nerve in rats and near a femoral artery in pigs (with a stimulation lead introduced into a blood vessel through a catheter) allowed for wireless stimulation of the animals’ sciatic and femoral nerves. Minimally invasive magnetoelectric implants may allow for the stimulation of nerves without the need for open surgery or the implantation of battery-powered pulse generators.