Multifunctional Fiber-based Optoacoustic Emitter as A Bidirectional Brain Interface.

A bidirectional brain interface with both "write" and "read" functions can be an important tool for fundamental studies and potential clinical treatments for neurological diseases. Here we report a miniaturized multifunctional fiber-based optoacoustic emitter (mFOE) that first integrates simultaneous optoacoustic stimulation for "write" and electrophysiology recording of neural circuits for "read". Because the intrinsic ability of neurons to respond to acoustic wave, there's no requirement of the viral transfection. The orthogonality between optoacoustic waves and electrical field provides a solution to avoid the interference between electrical stimulation and recording. We first validated the stimulation function of the mFOE in rat cultured neurons using calcium imaging. In vivo application of mFOE for successful simultaneous optoacoustic stimulation and electrical recording of brain activities was confirmed in mouse hippocampus in both acute and chronical applications up to 1 month. Minor brain tissue damage has been confirmed after these applications. The capability of simultaneous neural stimulation and recording enabled by mFOE opens up new possibilities for the investigation of neural circuits and brings new insights into the study of ultrasound neurostimulation. This article is protected by copyright. All rights reserved.