“Optical communication with brain cells by means of an implanted duplex micro-device with optogenetics and Ca2+ fluoroimaging”

TLDR

A minimally invasive, freely moving animal technology is needed to better understand brain function and advance neuroscience, regenerative medicine, and prosthetics. The study aims to develop a lightweight micro‑device that integrates optogenetic stimulation, fluorescence imaging, and a wearable implant to meet this need. The device combines dual LEDs and a CMOS image sensor to simultaneously deliver photostimulation and capture fluorescence, enabling bidirectional light‑based communication, and was evaluated in vitro with 3‑D neuroculture and in vivo with gene delivery and transplantation. The device successfully activated neural cells locally with selective photostimulation while simultaneously visualizing their Ca²⁺ dynamics via fluorescence imaging.

Abstract

Abstract To better understand the brain function based on neural activity, a minimally invasive analysis technology in a freely moving animal is necessary. Such technology would provide new knowledge in neuroscience and contribute to regenerative medical techniques and prosthetics care. An application that combines optogenetics for voluntarily stimulating nerves, imaging to visualize neural activity and a wearable micro-instrument for implantation into the brain could meet the abovementioned demand. To this end, a micro-device that can be applied to the brain less invasively and a system for controlling the device has been newly developed in this study. Since the novel implantable device has dual LEDs and a CMOS image sensor, photostimulation and fluorescence imaging can be performed simultaneously. The device enables bidirectional communication with the brain by means of light. In the present study, the device was evaluated in an in vitro experiment using a new on-chip 3D neuroculture with an extracellular matrix gel and an in vivo experiment involving regenerative medical transplantation and gene delivery to the brain by using both photosensitive channel and fluorescent Ca 2+ indicator. The device succeeded in activating cells locally by selective photostimulation and the physiological Ca 2+ dynamics of neural cells were visualized simultaneously by fluorescence imaging.