CAREER: Distributed, Wirelessly Powered, Implantable, Opto-Electro Neural Interface

Recent research has revealed that the complex functionality of the brain arises from the intricate interactions of a vast network of neurons spanning across interconnected regions of the brain. Therefore, future neural recording and modulation techniques require simultaneously interfacing with multiple neural sites that are distributed over a large brain area.

However, current neural interface devices typically consist of a single, centralized structure with transcutaneous connections to electrode/LED arrays, leading to scalability issues. A small number of recording/stimulation channels limits spatial coverage, whereas a large number of channels results in bulky device size, concentrated heat generation, and a high risk of wire connection failure.

The goal of this CAREER project is to explore a novel scaling solution involving a distributed untethered network of mm-scale, wirelessly powered, free-floating neural interface implants that enable optical stimulation and electrocorticography (ECoG) recording of large-scale neuronal ensembles over a large brain area. The proposed distributed neural interface system in this CAREER project will advance neuroscience studies and enhance the foundational understanding of the brain.

Additionally, this project will expand the utility and capabilities of the rapidly growing field of optogenetics, contributing to the development of new neural prostheses and neuromodulation therapies that can supplement current medication-based treatments for neurological disorders. The education plan of this project will make a significant impact on STEM engagement.

The plan involves developing multidisciplinary courses that can be cross-listed with related majors such as biomedical engineering, neural engineering, and neural science, providing research opportunities for students from a broad range of groups in STEM, and offering mentorship to students for their career development. Outreach activities will also be organized to facilitate the sharing of resources, tools, and knowledge with teachers and students.

The motivation of this CAREER project is to drive progress in the field of neural interfaces by enabling precise neural recording and targeted neuromodulation across a large brain area while minimizing invasiveness. Building upon this motivation, the primary goal is to create an innovative distributed untethered framework that consists of an array of untethered mm-scale wirelessly powered implantable opto-electro stimulation (WIOES) devices.

Each WIOES device will incorporate a flexible polyimide board that houses four planar recording electrodes and one LED along with an application-specific integrated circuit (ASIC) via a passive carrier chip, all packed in a compact (smaller than one mm cube) and lightweight package. These WIOES devices placed on the brain surface will record electrocorticography (ECoG) and apply energy-efficient optical stimulation while being wirelessly powered and monitored by an external controller via a dual-band resonance-based inductive wireless link.

Three research thrusts (RTs) are proposed to achieve the research goal. RT1 will be dedicated to developing the first compact neural implant smaller than one mm cube that has both optical stimulation and neural recording modalities. RT2 focuses on the development of a wireless and untethered neural interface system that relies on an innovative dual-band resonance-based inductive wireless link and an energy-efficient data communication protocol for wireless power and data transmission with the array of WIOES implants.

RT3 aims to assess the functionality and reliability of the proposed distributed WIOES implants through a series of in vitro and in vivo tests. The successful completion of this CAREER project will establish a new paradigm for neural interfaces, offering unique features such as wireless and untethered operation, wide spatial coverage, and minimal invasiveness.

This new paradigm will create new opportunities for neuroscience research and enable a deeper understanding of the brain.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.