Design, fabrication, and packaging of an integrated, wirelessly-powered optrode array for optogenetics application

Abstract

The recent development of optogenetics has created an increased demand for advancing engineering tools for optical modulation of neural circuitry. This paper details the design, fabrication, integration, and packaging procedures of a wirelessly-powered, light emitting diode (LED) coupled optrode neural interface for optogenetic studies. The LED-coupled optrode array employs microscale LED (μLED) chips and polymer-based microwaveguides to deliver light into multi-level cortical networks, coupled with microelectrodes to record spontaneous changes in neural activity. An integrated, implantable, switched-capacitor based stimulator (SCS) system provides high instantaneous power to the μLEDs through an inductive link to emit sufficient light and evoke neural activities. The presented system is mechanically flexible, biocompatible, miniaturized, and lightweight, suitable for chronic implantation in small freely behaving animals. The design of this system is scalable and its manufacturing is cost effective through batch fabrication using microelectromechanical systems (MEMS) technology. It can be adopted by other groups and customized for specific needs of individual experiments.

Modal demultiplexing properties of tapered and nanostructured optical fibers for in vivo optogenetic control of neural activity

“…This approach shows two major limitations: (i) the size of the implanted waveguide significantly damages the brain tissue, and (ii) it is not possible to redirect light in a different zone of the brain. Several alternative technological solutions have been developed recently to dynamically redirect light towards different locations of the brain tissue [8][9][10][11], including µ-Light Emitting Diodes [6,12,13], array of waveguides [14][15][16][17], bundle of optical fibers [18,19] or patterned illumination techniques [4,20,21].…”

Selective Manipulation of Neural Circuits

“…Although successfully applied to live and free-moving animals, this can limit the movement of animal and induce brain damage [127][128][129]. Recent efforts have been made to overcome this limitation with wireless head-mounted systems [130][131][132][133][134]. Although this system made it easy to apply optogenetics to free-moving animals, it is still invasive-wireless headstagemounted systems still need to implant optical fiber into the brain.…”

Fabrication and analysis of microfiber array platform for optogenetics with cellular resolution

“…In the past few years, a lot of efforts have been spent to design optogenetic probes in a dual optical and electrical way with high temporal and spatial resolution for in vivo applications. A new class of devices capable of delivering patterned light into different regions of brain based on SiON, glass, or SU8 resist waveguide in optrode array mode have been developed [4][5][6]. Short term in vivo optical experiments have been conducted in mouse model, however, resist waveguide could be degraded with continuous exposure to blue light in long term experiment [6].…”

“…A new class of devices capable of delivering patterned light into different regions of brain based on SiON, glass, or SU8 resist waveguide in optrode array mode have been developed [4][5][6]. Short term in vivo optical experiments have been conducted in mouse model, however, resist waveguide could be degraded with continuous exposure to blue light in long term experiment [6]. In contrast, optogenetic stimulation with single cell resolution using laser or light-emitting diode (LED) coupled fiber taper [7], micro LED array [8], digital micro mirror device (DMD)-based projector through a microscope [9], two-photon temporal focusing [10], etc, have also been developed.…”

“…The disadvantages of resist material and silica taper in chronic implantation applications could be minimized [5,6]. We developed a novel fabrication process to produce a microfiber array platform which has an illumination capability for single-cell optogenetic stimulation as a step toward future chronic in vivo applications.…”