Artifact-free, colocalized opto-electrophysiology enabled by a flexible, multimodal interface integrating transparent MXene microelectrodes and microLEDs

Abstract

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 Ti3C2Tx MXene micro-electrocorticography (μECoG) electrodes for simultaneous, crosstalk-free optical stimulation and electrical recordings. Transparent Ti3C2Tx 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 Ti3C2Tx 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 Ti3C2Tx 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.