A low-power implantable neurostimulator for small rodents with functional validation

Research applications in the field of bioelectronic medicine require miniaturized electronics for neurostimulation featuring high precision, long lifetimes, and small size. Existing devices are often limited by the battery capacity, durability of biocompatible packaging, and/or an experimental setup that restricts subject motion. To improve on these limitations, a neurostimulator for chronic implantation in mice was designed using standard off-the-shelf components and experimentally validated acutely in vivo. The device provides single-channel, constant-current monophasic stimulation with passive charge recovery. Magnetic control enables switching between active and electrical/physiological operational validation states. The quiescent current is 1.4 μA and active current is 160 μA with default stimulation parameters (250 μA amplitude, 32 Hz frequency, 100 μs pulse width), allowing the device to be powered by a single 3V lithium cell for up to 147 days with 2 hours of stimulation per day. The implant was packaged using biocompatible epoxy and preliminary accelerated soak testing results indicate a potential functional lifetime of up to 120 days.