ME-BIT animal proof of concept

The 2022 paper tests magnetoelectric ME-BIT hardware in direct-contact rat sciatic stimulation and pig vascular-lead stimulation. It also separately demonstrates device deployment into a femoral artery. These are not one identical procedure or a completed clinical system.

Cohort scopes and conflict

Results and the reporting summary say two rats supplied the demonstrated stimulation evidence. Methods says stimulation was confirmed in three male Long-Evans rats, 300-400 g. The fetched sources do not resolve that difference; no animal count is silently selected as universal.

Pig Methods describes eight female Yorkshire pigs, 35-45 kg. The reporting summary says data are shown for one pig and additional animals were pilots. Femoral and segmental stimulation are repetitions within that pig, not eight independent outcome datasets. No blinding was used and the summary reports no data exclusions.

Rat direct-contact stimulation

The 6.2-mm³/30-mg device rested directly on the sciatic nerve. Rat A used an untethered implant with 1-cm transmitter distance and 3-V, 1.5-ms monophasic pulses at 3 Hz. Rat B’s amplitude sweep used 0.3-3.1 V at 1 Hz with 1.5-ms width; recorded CMAP amplitude saturated at higher voltage. These protocol values are distinct from the ASIC paragraph’s 1.2-ms maximum-width statement.

Pig stimulation was not entirely catheter-only

For physiological stimulation, the paper describes a hind-leg incision exposing the femoral neurovascular bundle. The implant was placed near the vessel and its parylene-insulated lead was introduced through a 9 Fr sheath into the femoral artery. The external transmitter powered it at approximately 1.5 cm beneath skin. Thus, the demonstrated nerve response does not mean the full implant was delivered and operated without open surgical exposure in that experiment.

Femoral stimulation used 3-V, 1.5-ms monophasic pulses, including 10 Hz. EMG, nerve action potentials and averaged somatosensory responses supported nerve-mediated stimulation. Off-resonant magnetic controls produced no response. Segmental-artery leads also supported intercostal/DRG-target experiments at 1-10 Hz.

Delivery and follow-up boundary

A separate X-ray demonstration shows the full ME-BIT deployed through a 9 Fr sheath into the femoral artery. That delivery image does not establish chronic anchoring, embolization resistance or long-term stimulation from the same intravascular position.

Acute artery histology showed no observed damage. Animals were euthanized after the study; there is no months-long vascular survival cohort. Chronic thrombosis, packaging, PZT isolation and exposure-standard questions remain open.

Primary sources

• Published primary paper,Figures4/5 and Discussion.
• Published PDF,Methods and reporting summary.