Extended Data Fig. 8: Evaluation of optical illumination through implanted hydrogel fibers.

a, Schematic of the temperature measurement through a resistance temperature detector (RTD) at the hydrogel cuff in air. The light source delivers 473-nm optical pulses with an irradiance of 35.4 mW mm⁻². b, Plots of temperature variation in air when the optical pulses exhibit different duty cycles (DCs). Blue bars indicate optical pulses. c, Temperature increase in air under optical pulses with different DCs. d, Schematic of the temperature measurement through an RTD at the hydrogel cuff in mice. The light source delivers 473-nm optical pulses with an irradiance of 35.4 mW mm⁻². e, Plots of temperature variation in mice when the optical pulses exhibit different DCs. Blue bars indicate optical pulses. f, Temperature increase in mice under optical pulses with different DCs. g, Ray tracing simulation of hydrogel fibers with the hydrogel cladding. h, Images of a mouse implanted with a hydrogel fiber with the hydrogel cladding, showing on-target illumination. i, Ray tracing simulation of hydrogel fibers without the hydrogel cladding. j, Images of a mouse implanted with a hydrogel fiber without the hydrogel cladding, showing off-target illumination. k-l, Darkfield (DF) and brightfield (BF) images of a mouse implanted with a hydrogel fiber (no cladding) when the fiber is relaxed (k) and stretched (l). Contours of the hydrogel fiber without cladding are visible in the darkfield. The skin on top of the sciatic nerve is labeled with a green sticker to identify the original sciatic nerve position. m, Change of fiber length and nerve dislocation over fiber stretch cycles. n, Images of the hydrogel cuff before and after 8-week implantation in mice.

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