Soft subdermal implant capable of wireless battery charging and programmable controls for applications in optogenetics

Choong Yeon Kim,Kum Seok Nam,Jeong-Hoon Kim,Jong Woo Park,Min Jeong Ku,Inho Kang,Shane Oh,Raza Qazi,Jae-Hyung Jang,Wha Young Kim,Jae-Woong Jeong,Hong Jae Nam

doi:10.1038/s41467-020-20803-y

Abstract

Optogenetics is a powerful technique that allows target-specific spatiotemporal manipulation of neuronal activity for dissection of neural circuits and therapeutic interventions. Recent advances in wireless optogenetics technologies have enabled investigation of brain circuits in more natural conditions by releasing animals from tethered optical fibers. However, current wireless implants, which are largely based on battery-powered or battery-free designs, still limit the full potential of in vivo optogenetics in freely moving animals by requiring intermittent battery replacement or a special, bulky wireless power transfer system for continuous device operation, respectively. To address these limitations, here we present a wirelessly rechargeable, fully implantable, soft optoelectronic system that can be remotely and selectively controlled using a smartphone. Combining advantageous features of both battery-powered and battery-free designs, this device system enables seamless full implantation into animals, reliable ubiquitous operation, and intervention-free wireless charging, all of which are desired for chronic in vivo optogenetics. Successful demonstration of the unique capabilities of this device in freely behaving rats forecasts its broad and practical utilities in various neuroscience research and clinical applications.

Highlights

Optogenetics is a powerful technique that allows target-specific spatiotemporal manipulation of neuronal activity for dissection of neural circuits and therapeutic interventions
Some recent advances have tried to combine batteries with a wireless energy-harvesting module in implantable systems to enable wireless charging of batteries. Their bulky and rigid configurations limit biomechanically compatible chronic use within the body, and the wireless charging capability in freely moving animals has not been demonstrated[28,29]. To overcome these challenges and maximize the use of wireless optogenetics, we present a fully implantable, soft, wirelessly rechargeable optoelectronic systems that can be conformally integrated within the body and can be controlled by a readily available smartphone
The wireless optoelectronic system consists of four main functional parts: (i) optoelectronic neural probes for photostimulation, (ii) a power management circuit with a flexible coil antenna and a rechargeable Lithium Polymer (LiPo) battery (GMB-300910, PowerStream Technology) for wireless charging and operation, (iii) Bluetooth Low Energy System-on-Chip (BLE SoC; RFD77101, RF Digital Corporation) for wireless control, and (iv) soft polymer encapsulation for biocompatible device packaging

Summary

Introduction

Optogenetics is a powerful technique that allows target-specific spatiotemporal manipulation of neuronal activity for dissection of neural circuits and therapeutic interventions. Current wireless implants, which are largely based on battery-powered or battery-free designs, still limit the full potential of in vivo optogenetics in freely moving animals by requiring intermittent battery replacement or a special, bulky wireless power transfer system for continuous device operation, respectively To address these limitations, here we present a wirelessly rechargeable, fully implantable, soft optoelectronic system that can be remotely and selectively controlled using a smartphone. Battery-free implants with miniaturized radiofrequency (RF) energy-harvesting circuits, on the other hand, overcome this limitation by allowing their full implantation inside the body[22,23,24,25,26,27] Their wireless operation is susceptible to angular orientations, does not support selective control among multiple animals mingled together, and most importantly, always requires special bulky cages equipped with an RF power transfer system. Our in vivo studies with freely behaving animals and phantom human models demonstrate the broad utility and immense potential of wirelessly rechargeable implants for neuroscience research and clinical applications

Methods

Results

Conclusion