Multifunctional Flexible Biointerfaces for Simultaneous Colocalized Optophysiology and Electrophysiology

Recent developments in optophysiology techniques such as optogenetics have revolutionized the ability to actuate cell activity. Further combining optophysiology and electrophysiology will integrate the advantages from both optical and electrical modalities and yield enabling technologies that allow simultaneous monitoring of cellular activity in response to modulation, which are crucial for biomedical applications. However, multifunctional devices that can deliver optical stimuli to regions beneath the electrodes and perform simultaneous sensing remain largely unexplored. Existing transparent microelectrode technologies depend on external bulk optical instruments for optical interventions. Here, innovative monolithic integrated multifunctional microsystems are demonstrated by applying transparent nanogrid electrodes onto microscale light sources to permit simultaneous electrophysiology and optical modulation at the same anatomical site. The nanogrid electrodes have transmittances > 70% with a low normalized impedance of 5.9 Ω cm². Additional features of the devices include superior mechanical flexibility, minimized light-induced electrical artifacts, and excellent biocompatibility. Ex vivo experiments demonstrate that the multifunctional devices can record abnormal heart rhythm in transgenic mouse hearts and simultaneously restore the sinus rhythm via optogenetic pacing. This work provides a versatile approach for constructing multifunctional colocalized biointerfaces containing crosstalk-free optical and electrical modalities with expanded opportunities in both fundamental and applied biomedical research.