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. Author manuscript; available in PMC: 2022 Feb 16.
Published in final edited form as: Nat Biotechnol. 2021 Sep 27;40(2):198–208. doi: 10.1038/s41587-021-01019-x

Fig. 1. Wireless optoelectronic system for closed-loop photostimulation of the lumbar spinal cord.

Fig. 1

a, Schematic overview of optoelectronic system, including a zoom on the insertion of the micro-LED array over the epidural surface of the spinal cord.

b, Photographs of the micro-LED array, including a zoom on the micro-LEDs, and exploded diagram of the array.

c, Optoelectronic characterization under incremental bias (λ = 470 nm).

d, Stretchability. The optoelectronic implant was cycled at 15% strain, which corresponds to the range of motion of the lumbar spinal cord, for 100’000 cycles while continuously emitting light (n = 3, mean±s.e.m.).

e, Accelerated aging. The optoelectronic implant was immersed in 67°C saline to accelerate degradation. The devices start failing around 40 days (n = 4, mean±s.e.m.).

f, Photographs of the electronics embedded in the wireless, head-mounted platform that records physiological signals and power the optoelectronics.

g, In-air antenna radiation characteristics, measured in an anechoic chamber with a battery-operated software-modified version of the headstage wireless device (emitting a carrier) and a linearly polarized receive antenna. Drawn lines represent measurements at centre frequency (2440MHz) while the shades cover the full Bluetooth Low Energy bandwidth based on additional measurements at 2400MHz, 2420MHz, and 2480MHz.