Toward a fully wireless endovascular neural interface: Evaluating power transfer efficacy.

Area of Science:

• Biomedical Engineering
• Neurotechnology
• Wireless Power Transfer

Background:

• Endovascular neural interfaces (ENIs) offer minimally invasive neural stimulation and recording.
• Current ENIs require transvascular wires, posing risks like infection and thrombosis.
• Eliminating wires necessitates efficient wireless power transfer across the skull within safety limits.

Purpose of the Study:

• To design and evaluate endovascular receiver (Rx) and transmitter (Tx) coils for maximized wireless power transfer.
• To optimize power delivery within endovascular geometric and biological constraints.
• To address the challenge of efficient power transfer across the skull for ENIs.

Main Methods:

• Computational modeling, benchtop, and in-vivo testing were used.
• Evaluated optimal frequencies, coupling, coil quality factors, power transfer efficiency (PTE), and specific absorption rate (SAR).
• Assessed coil performance with and without ferrites, in air, sheep tissue, and in vivo, testing tolerance to misalignment and load mismatch.

Main Results:

• Inductive power transfer successfully delivered power to endovascular devices at clinically relevant depths.
• Maximum PTE reached 11% at 15 mm and 2% at 30 mm.
• Up to 72 mW was delivered at 30 mm within SAR limits; ferrite-core coils were superior beyond 20 mm and more tolerant to misalignment.

Conclusions:

• Demonstrated feasibility of wirelessly powering multichannel ENIs using implantable inductive coils.
• Wireless power transfer can significantly improve the safety and reliability of endovascular neural interfaces.
• This technology has the potential to transform neural interfacing by removing transvascular wires.