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An implant that can electrically stimulate neurons across different depths and regions of the brain currently does not exist as it poses a number of obstacles that need to be solved. In order to address the challenges, this paper presents the concept of "microbead," a fully integrated wirelessly powered neural device that allows for spatially selective activation of neural tissue. The prototype chip is fabricated in 130-nm CMOS technology and currently measures 200 μm × 200 μm, which represents the smallest remotely powered stimulator to date. The system is validated experimentally in a rat by stimulating the sciatic nerve with 195-μs current pulses. To power the ultrasmall on-silicon coil, 36-dBm source power is provided to a highly optimized transmitter (Tx) coil at a coupling distance of 5 mm. In order to satisfy the strict power limit for safe use in human subjects, a pulsed powering scheme is implemented that enables a significant decrease in the average power emitted from the Tx.
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http://dx.doi.org/10.1109/TBCAS.2018.2802443 | DOI Listing |
HardwareX
September 2025
GET UMR234, Université de Toulouse, CNRS, IRD, UPS, CNES, 31400 Toulouse, France.
In this paper we present the design, construction and performance of a self-contained float-controlled water level gauge for monitoring water levels in streams and small rivers. This device is inexpensive (cost of about EUR 220), easy to build (no electronics skills or specialized tools required; assembled in a few hours) and straightforward to use. The gauge remains autonomously operational for several weeks in remote locations without the need for an external power supply or solar panel and in the harsh tropical climatic conditions.
View Article and Find Full Text PDFIEEE J Solid-State Circuits
November 2024
Department of Electrical Engineering and Computer Sciences, University of California at Berkeley, Berkeley, CA 94720 USA and also the Department of Radiation Oncology, University of California, San Francisco, CA 94158 USA.
Real-time monitoring of dynamic biological processes in the body is critical to understanding disease progression and treatment response. This data, for instance, can help address the lower than 50% response rates to cancer immunotherapy. However, current clinical imaging modalities lack the molecular contrast, resolution, and chronic usability for rapid and accurate response assessments.
View Article and Find Full Text PDFSci Rep
July 2025
Electrical and Computer Engineering, University of California Los Angeles, Los Angeles, CA, USA.
Vagus nerve stimulation (VNS) has been explored as a treatment for a range of conditions, including epilepsy, cardiovascular disorders, drug-resistant depression, chronic pain, and obesity. Conventionally, VNS is administered using an open-loop approach, in which trained personnel adjust stimulation parameters. Medical supervision is necessary to minimize adverse effects, such as severe bradycardia, which can significantly interfere with daily activities.
View Article and Find Full Text PDFRSC Adv
July 2025
Materials Science and Engineering, School for Engineering of Matter, Transport and Energy, Arizona State University Tempe AZ 85287 USA
Parylene is widely recognized as an effective candidate for encapsulating implantable bioelectronics due to its outstanding chemical stability, conformity and biocompatibility. However, its weak adhesion to inorganic substrates remains a significant challenge. Here, we explored various pre- and post-deposition treatments to enhance adhesion and stability of parylene coating for implantable brain-machine interfaces (BMIs).
View Article and Find Full Text PDFIEEE Trans Ultrason Ferroelectr Freq Control
September 2025
Ultrasound (US) is a promising modality for wirelessly powering implantable devices, requiring encapsulated receivers to ensure long-term stability. Traditional hermetic packaging often limits acoustic transmission, making polymer-based encapsulation a more suitable alternative. This study investigates how implant-grade polymers, thermoplastic polyurethane (TPU), parylene-C, and medical-grade silicones (MED-1000 and MED2-4213), affect the receive performance of piezoelectric micromachined ultrasonic transducers (PMUTs).
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