Fabrication and characterization of ultra-flexible optoelectrodes for chronic opto-electric neural interfaces

The combination of optogenetic modulation and electrical neural recording allows for the interrogation of neural circuits with millisecond temporal resolution and cell type specificity, offering promising prospects for fundamental neuroscience research. However, the mechanical stress exerted by conventional rigid neural probes on surrounding tissues postimplantation can elicit the inflammatory response or neuronal death, thereby compromising their long-term performance. In this study, we propose a novel ultra-flexible polymer-based neural optoelectrodes design that is monolithically manufactured using planar semiconductor fabrication technology. Furthermore, we characterize its optical propagation and in vivo neural recording performance. Compared to previous approaches, our innovative optoelectrodes design offers improved flexibility and biocompatibility, providing unparalleled versatility for investigating neural circuits with high spatiotemporal precision. Our work paves the way for stable long-term multimodal neural interfacing applications in the future.