An Integrated μLED Optrode for Optogenetic Stimulation and Electrical Recording

TLDR

Optogenetics enables highly specific, temporally precise stimulation of neural circuits via light‑gated ion channels. The study develops an integrated μLED optrode that simultaneously stimulates and records neural activity on a single‑polyimide platform. The probe uses a μLED with an integrated photo‑polymerized lens to focus light, while microelectrodes record neuronal activity near the stimulation site, allowing closed‑loop feedback. In mice expressing channelrhodopsin‑2, the device recorded intensity‑ and frequency‑dependent spiking in visual cortex and outperformed fiber‑coupled laser optrodes in compactness, integration, and power consumption, indicating clinical potential.

Abstract

In this letter, we developed an integrated neural probe prototype for optogenetic stimulation by microscale light-emitting diode (μLED) and simultaneous recording of neural activities with microelectrodes on a single-polyimide platform. Optogenetics stimulates in vivo neural circuits with high-cellular specificity achieved by genetic targeting and precise temporal resolution by interaction of light-gated ion channels with optical beam. In our newly developed optrode probe, during optogenetic stimulation of neurons, continuous sensing of neuronal activities in vicinity of the activation site can provide feedback to stimulation or examine local responses in signal pathways. In the device, focusing the light from the μLED was achieved with an integrated photo-polymerized lens. The efficacy of the optrode for cortical stimulation and recording was tested on mice visual cortex neurons expressing channelrhodopsin-2. Stimulation intensity and frequency-dependent spiking activities of visual cortex were recorded. Our device has shown advantages over fiber-coupled laser-based optrode in terms of closed-loop integration, single-implant compactness and lower electrical power requirements, which would be clinically applicable for future prosthetic applications in personalized medicine.