Optogenetic brain neuromodulation by stray magnetic field via flash-enhanced magneto-mechano-triboelectric nanogenerator

Abstract Optogenetic neuromodulation is a promising technology for continuously caring various neurological diseases. Optogenetic modulating systems were demonstrated by several researchers, but still have critical issues of short lifetime of conventional or biocompatible batteries. Here, we present an optogenetic stimulating system by scavenging wasted magnetic field of home appliance. A flash-enhanced magneto-mechano-triboelectric nanogenerator (MMTENG) was fabricated to demonstrate optogenetic neuromodulation by operating a flexible micro-light-emitting diode (f-μLED). The output performance of MMTENG was enhanced by the flash-induced nano/microscale surface structure of the triboelectric Nylon film. The flash-stamped MMTENG effectively generated an open-circuit peak-to-peak voltage (Vpp) of 870 V and a short-circuit current of 145 μA under a gentle alternating current (AC) magnetic field of 7 Oe. A maximum peak power of 8.1 mW was observed from the flash-induced harvester, which was 2.6 times higher than the non-treated device. A high-performance f-μLED with low-resistive ohmic contacts had the improvement of thermal/mechanical stability as well as power efficiency. The MMTENG generated a rectified output voltage of 134 V by a 60 Hz stray magnetic field of home appliance, enabling to operate the f-μLED continuously. An optogenetic stimulator composed of MMTENG and f-μLED was implanted under a living mouse skull without mechanical damage.