Fully implanted battery-free high power platform for chronic spinal and muscular functional electrical stimulation

• Published in: Nature communications 2023-11, Vol.14 (1), p.7887-7887, Article 7887
• Main Authors: Burton, Alex, Wang, Zhong, Song, Dan, Tran, Sam, Hanna, Jessica, Ahmad, Dhrubo, Bakall, Jakob, Clausen, David, Anderson, Jerry, Peralta, Roberto, Sandepudi, Kirtana, Benedetto, Alex, Yang, Ethan, Basrai, Diya, Miller, Lee E., Tresch, Matthew C., Gutruf, Philipp
• Format: Article
• Language: English
• Subjects: 631/378/1687/1825; 631/378/1959/2605; 631/61; 639/166/985; Biomedical materials; Design optimization; Electrical stimuli; Humanities and Social Sciences; multidisciplinary; Muscles; Neuromuscular system; Power transfer; Resonators; Science; Science (multidisciplinary); Spinal cord injuries; Stimulation; Telemetry; Voltage
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-43669-2

Electrical stimulation of the neuromuscular system holds promise for both scientific and therapeutic biomedical applications. Supplying and maintaining the power necessary to drive stimulation chronically is a fundamental challenge in these applications, especially when high voltages or currents are required. Wireless systems, in which energy is supplied through near field power transfer, could eliminate complications caused by battery packs or external connections, but currently do not provide the harvested power and voltages required for applications such as muscle stimulation. Here, we introduce a passive resonator optimized power transfer design that overcomes these limitations, enabling voltage compliances of ± 20 V and power over 300 mW at device volumes of 0.2 cm 2 , thereby improving power transfer 500% over previous systems. We show that this improved performance enables multichannel, biphasic, current-controlled operation at clinically relevant voltage and current ranges with digital control and telemetry in freely behaving animals. Preliminary chronic results indicate that implanted devices remain operational over 6 weeks in both intact and spinal cord injured rats and are capable of producing fine control of spinal and muscle stimulation. Electrical stimulation of the neuromuscular system holds promise for therapeutic biomedical applications, but is currently restricted by power. Here, the authors introduce fully implantable resonator-based designs achieving ±20 V compliance and >300 mW output, enabling multichannel, biphasic, current-controlled operation to evoke functional gate patterns for 6-weeks in freely behaving rats.