Soft and Optically Transparent Kirigami-Based Neural Interfaces

Recent progress in neuroscience has driven the need for coupled electronic and optical neural interfacing, particularly in the context of optogenetic studies where brain electrophysiological signals are measured in response to light stimulation. A major challenge in these experiments is the compatibility of neural electrode arrays with optical stimulation, due to the inherent reflectivity of the conductors used as electrode and interconnect materials. Here, we propose a soft neural interface with transparent and stretchable interconnects enabling optical stimulation across the entire device area while preserving full flexibility in the device placement for electrophysiology recordings. We use micropatterned stacks of Parylene-C (PaC) and Indium Tin Oxide (ITO) encapsulated in silicone to achieve both stretchability up to 5 0 0 k cycles at 5% uniaxial strain with 8% change in resistance, and high optical transparency with over 80 % transmittance in the 350-650 ∼nm wavelength range. We demonstrate a thin-film transparent μ E C o G device supporting acute recording light induced neural activation of the auditory cortex of a Thy-1 rat, with a SNR of 3 ∼V / V.