Dual-color μ-LEDs integrated neural interface for multi-control optogenetic electrophysiology

Over recent decades, optogenetics has become a pivotal technique for elucidating the functionality of neuronal circuits in living organisms. By genetically modifying specific cells within targeted tissues to respond to particular optical stimuli, researchers can achieve precise activation or inhibition of these cells. This capability enables detailed investigations of neural circuitry with unprecedented accuracy. However, there is a rising need for hardware that supports bidirectional control in conjunction with electrophysiological recording. A significant challenge in this domain is the compact integration of dual light sources and a recording system. This study addresses this challenge through the development of a novel microfabrication and assembly technique for embedding dual-color micro-LEDs and recording electrodes into a Michigan-type neural probe structure, designated as DuoLite (Dual-color micro-LEDs Integrated Neural-Interface Optoelectrode for Multi-Control Optogenetic Electrophysiology). We present two device variants: (a) a small-group and (b) a large-group cell-targeted design, each incorporating micro-LEDs with a minimal area of <100 μm ² for both red and blue light. The design and assembly techniques for integrating all three components within a shank width of <100 μm are thoroughly detailed, and the functionality of the devices is validated through in vivo experiments.