Intraneural SiC multi electrodes to detect multimodal sensory signals

Limb prosthesis technology now incorporates actuation and touch sensing information, however evoking such specific types of sensation to amputee users remains a challenge, in part due to the low spatial resolution of microelectrodes in peripheral neural interfaces relatively large active areas (i.e.., 2000 um
²
) at the tip and shafts of 100–200 um
²
OD. Here we implemented a sixteen-channels ultra-small multi electrode arrays (UMEA) with 10 um OD shafts and 200 um
²
surface area using amorphous silicon carbide (a-SiC) for high precision intraneural detection of cutaneous sensory signals. This technology allowed to discriminate between slow and rapid adapting mechanoceptors associated to light and deep pressure in response to touch stimulation using von Frey filaments. We observed specific electrophysiological profiles evoked from five glabrous dermatomes, which inform neural subtypes and spatial arrangement in the nerve. The results demonstrate that ultra-small UMEA can be used reliably to record specific sensory modalities from the peripheral nerves, which could offer a viable alternative to inform closed loop systems to decode movement intent and to evoke specific sensations through microstimulation.