A multi-site MicroLED Optrode Array for Neural Interfacing

Abstract

We present an electrically addressable optrode array capable of delivering light to 181 sites in the brain, each providing sufficient light to optogenetically excite hundreds of neurons in vivo, developed with the aim to allow behavioural studies in large mammals. The device is a glass microneedle array directly integrated with a custom fabricated microLED device, which delivers light to 100 needle tips and 81 interstitial surface sites, giving 2-level optogenetic excitation of neurons in vivo. Light delivery and thermal properties are evaluated, with the device capable of peak irradiances > 80 mW/mm 2 per needle at 50 ms pulse widths with tissue temperature increase less than 1 °C . Future designs are explored through optical and thermal modelling and benchmarked against the current device.

Optogenetics in primate cortical networks

“…Self-contained optical devices are being developed with inbuilt microLED arrays and at times penetrating optical guides (McAlinden et al, 2019;Mondello et al, 2021). These devices would allow for selective power increase via the optrode shank, without increase in light power to the cortical surface, while also positioning microLEDs in direct contact with optrode shanks, which minimizes light loss.…”