Fig. 4: Optoelectronic stimulation of sciatic nerves of SD rats with Si-based neural interfaces.
a Schematic illustration of a Si-based optoelectronic device attached to the sciatic nerve of the right hind limb of the rat for optoelectronic stimulation. Electromyography (EMG) recording electrodes are inserted into the gastrocnemius muscles of the right hind limb associated with the sciatic nerve to record the compound muscle action potential (CMAP). b Photograph of the implantation of a biodegradable silicon-based optoelectronic device on to the sciatic nerve. c Photograph of the movement of the right hind limb of the rat induced by pulsed laser illumination (635 nm, 0.95 W/cm2, 10 Hz, pulse width 10 ms). d Recorded CMAP amplitude (peak-peak value) from optoelectronic stimulation of the sciatic nerve with Si/Mo and Si/Au devices (4 mm in diameter) under various light intensities. e Direct laser irradiation (0.95 W/cm2), Si device (no interface modification) and Si/Au devices (2 mm in diameter) under laser illumination (0.95 W/cm2) elicit negligible response of the sciatic nerve. f Representative evoked CMAP induced by laser irradiation (0.95 W/cm2) on different devices: Si/Mo devices (4 mm or 2 mm in diameter) and Si/Au devices (4 mm in diameter). g, h CMAP amplitude (peak-peak value) and limb displacement induced by optoelectronic stimulation (0.95 W/cm2) of Si/Mo devices (4 mm or 2 mm in diameter) and Si/Au devices (4 mm in diameter). In b–h, n = 5 independent devices for each groups. All data are presented as mean ± s.e.m. Statistics is analyzed through SPSS (version 23.0), followed by one-way ANOVA (* p < 0.05, ** p < 0.01, *** p < 0.001). The box plot presents the median (center line), lower quartile (lower border), upper quartile (upper border), maximum (upper whisker) and minimum (lower whisker), which are ≤ 1.5 times the interquartile range.
