Artifact-free, colocalized opto-electrophysiology enabled by a flexible, multimodal interface integrating transparent...

Neurotechnologies capable of both modulating and recording neural activity are critical for investigating neural function and disease. Optoelectronic probes incorporating micro-light-emitting diodes (μLEDs) and transparent microelectrodes enable colocalized optogenetic stimulation and electrophysiological recordings with high spatiotemporal resolution but often suffer from stimulation artifacts. In this work, we present a thin, flexible, and conformal neural interface integrating blue μLEDs (460 nm) with transparent Ti₃C₂T_x MXene micro-electrocorticography (μECoG) electrodes for simultaneous, crosstalk-free optical stimulation and electrical recordings. Transparent Ti₃C₂T_x μECoG electrodes show an optical transmittance of 54.9 ± 0.9% at 460 nm and an impedance modulus of 291.9 ± 99.9 kΩ at 1 kHz. The μLEDs provide up to 86.1 ± 14.7 mW mm^-2 with minimal tissue heating and negligible optical distortion through transparent Ti₃C₂T_x channels. We systematically investigate the mechanisms of the stimulation artifacts and present a methodological framework that is generalizable across multimodal neural interface materials and geometries. With this framework, we demonstrate that the Ti₃C₂T_x electrodes are minimally susceptible to photoelectric artifacts and that the remaining electromagnetic interference artifacts are minimized using transient μLED drive pulse shaping, ultimately achieving artifact-free, colocalized functionality. The novel multimodal interface is validated in an acute mouse model, establishing it as a powerful platform that enables bidirectional, crosstalk-free interrogation of neural circuits with high spatiotemporal precision.