Differential Tissue Coupled Powering for Battery-Free Injectable Electroceuticals

Electroceutrical implants that deliver targeted neural stimulation show strong therapeutic promise, yet wirelessly powering ultra-miniaturized, fully injectable systems remains challenging. Here we present a thread-like injectable neural technology (TINY) powered by a differential tissue-coupled powering (DTCP) scheme. DTCP applies mid-frequency differential potentials across external electrodes on a compact wearable transmitter to deliver energy through tissue to an implant integrating a custom ASIC and PEDOT-coated electrodes. Benchtop studies in agar phantoms reveal that DTCP’s power-transfer efficiency increases with implant length without a proportional increase in cross-section or overall volume, while maintaining high angular misalignment tolerance. In vivo tests in rat hindlimbs demonstrate wireless sciatic nerve activation, confirming effective transcutaneous energy delivery. A 20-day implantation study further shows stable positioning and minimal tissue response, indicating chronic compatibility. DTCP thus overcomes key limitations of conventional wireless powering and provides a scalable, alignment-robust strategy for minimally invasive electroceutical therapies.