Multi‐wavelength light emitting diode‐based disposable optrode array for in vivo optogenetic modulation

Abstract

We present a light emitting diode (LED)‐based optical waveguide array that can optogenetically modulate genetically targeted neurons in the brain. The reusable part of the system consists of control electronics and conventional multi‐wavelength LED. The disposable part comprises optical fibers assembled with microlens array fabricated on a silicon die. Both parts can be easily assembled and separated by snap fit structure. Measured light intensity is 3.35 mW/mm2 at 469 nm and 0.29 mW/mm2 at 590 nm when the applied current is 80 mA. In all the tested conditions, the light‐induced temperature rise is under 0.5°C and over 90% of the relative light intensity is maintained at 2 mm‐distance from the fiber tips. We further tested the efficiency of the optical array in vivo at 469 nm. When the optical array delivers light stimulation on to the visual cortex of a mouse expressing channelrhodopsin‐2, the neural activity is significantly increased. The light‐driven neural activity is successfully transformed into a percept of the mouse, showing significant learning of the task detecting the cortical stimulation. Our results demonstrate that the proposed optical array interfaces well with the neural circuits in vivo and the system is applicable to guide animal behaviors.

Multisite microLED optrode array for neural interfacing

“…Coupling of a single LED into multiple fibers has also been tested, giving multisite illumination, but without individual control of illumination sites. 14 …”

Implantable Optrode Array for Optogenetic Modulation and Electrical Neural Recording

“…The utility of the optical system was verified in previous studies in terms of light intensity, heat dissipation, and spatial light distribution [21,25]. In this study, a new optrode array integrated with electrophysiological recording electrodes was proposed so that the neural activity from adjacent neurons evoked by optogenetic stimulation could be recorded.…”

“…When the LED is turned on, the light passes through the MLA and the optical fiber array and reaches the fiber tip to illuminate the target region. In the previous study, it was shown that the temperature increase at the optical fiber tip was less than 0.5 • C, and the relative light intensity remained above 91% up to a distance of 2 mm from the tip [21]. The excitation parameters can be controlled by changing the frequency, pulse width, application time, and input current using the external power supply.…”

“…optical fiber tip was less than 0.5 °C, and the relative light intensity remained above 91% up to a distance of 2 mm from the tip [21]. The excitation parameters can be controlled by changing the frequency, pulse width, application time, and input current using the external power supply.…”

“…An integrated device that can simultaneously deliver light stimuli to activate or inhibit specific neuronal cells and record the neural response activities has been highly demanded [9,[11][12][13][14][15][16][17][18]. As this micro-electro-mechanical systems (MEMS) technology advances, optical stimulation and recording system configuration can be fabricated on a microscale [19][20][21][22][23][24][25]. Therefore, a MEMS-based optrode is considered to be one of the promising optogenetic platforms.…”