Browsing by Author "Robinson , Jacob"

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    Magnetoelectric Materials for Miniature, Wireless Neural Interfaces
    (2018-04-20) Wickens, Amanda; Robinson , Jacob
    Developments in wireless neuromodulation technologies have lead to new treatments for neurological disorders and new methods of probing neural circuits in humans and animal models. Miniaturized and wirelessly powered biomedical implants are being developed in order to minimize the perturbation and damage to the neural circuits and surrounding tissue. However, developing devices capable of transmitting sufficient power in small form factors remains a challenge. Conventional wireless neural stimulation devices need to be connected to a bulky battery pack or coil of wire that, when miniaturized, suffers from reduced power transfer, high angle dependence, and requires high ~MHz frequency electromagnetic fields to carry the power. This limits the applications for any given device and can cause a negative host response due to the larger implants and leads. Here we show magnetoelectric devices capable of transforming external magnetic fields to controllable electric fields strong enough to wirelessly stimulate targeted neural regions in freely moving rats with no genetic modification. We found that by coupling a piezoelectric and magnetostrictive material at an acoustic resonance, magnetoelectric films can stimulate cells in vitro when we apply an external magnetic field. We are currently working to further show that these electric fields are strong enough to stimulate activity wirelessly by powering implanted electrodes in freely moving rats. Furthermore, in contrast to traditional inductive coupling, we show magnetoelectric materials are scalable and still capable of generating large voltages with a small device footprint. Our results demonstrate that magnetoelectric materials can be used to develop versatile lightweight wireless neural implants. We lay the foundation for further developing these materials to be used for many different applications in neuroscience.
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    Wireless Magnetoelectric Communication for Bioelectronics
    (2024-04-19) Alrashdan, Fatima; Robinson , Jacob
    Implantable bioelectronics hold great potential to improve the diagnosis and treatment of myriad chronic health conditions. Wireless bioelectronic implants that continuously monitor the patient’s physiological state and transmit these data in real-time without tethers would improve diagnosis and facilitate adaptive therapeutic interventions. However, existing wireless communication modalities, such as Bluetooth, radio frequency, and ultrasound, have performance trade-offs regarding implant size, misalignment tolerance, power consumption, and operational distance. In this dissertation, I present the first wireless backscatter magnetoelectric communication system that features a miniaturized size, ultra-low power consumption, and deep operational distance with high misalignment tolerance. The system leverages two fundamental characteristics of the magnetoelectric transducers. Firstly, magnetoelectric materials generate a backscattered magnetic field when excited by an external field; we exploit these fields as a carrier signal. The magnetoelectric implant consumes negligible power for carrier generation since the external field that induces this signal is generated outside the body. Secondly, the characteristics of the backscattered field can be modulated by an external electric load; thus, we can use load modulation for digital data encoding. This design enables continuous, real-time data transmission from a mm-sized magnetoelectric. bioimplant to a custom-designed external transceiver. Our benchtop testing shows that the system can support an operational range within 55 mm while maintaining a bit error rate (BER) of less than 1E-6. Furthermore, the system is robust to translational misalignment; the system performance is maintained with a misalignment of more than 10 mm. To validate the system reliability in real-life applications and facilitate the clinical translation of this technology, we tested the system operation in a porcine model. We have shown two demonstrations of in-vivo studies: wireless monitoring of stimulation electrode impedance for cortical brain implants and real-time remote monitoring of electrical intracardiac signals for cardiac implants. The proposed technology could enable the design of next-generation bioelectronics that feature real-time physiology monitoring for more precise diagnosis, as well as closed-loop systems for personalized therapies.