Tissue-integrating Neural Interfaces

Solvent evaporation or entrapment-driven (SEED) integra­tion is a rapid, robust, and modular approach to creating multifunctional fiber-based neural interfaces. SEED integra­tion brings together electrical, optical, and microfluidic modalities within a co-polymer comprised of water-soluble poly(ethylene glycol) tethered to water-insoluble poly(ur­ethane) (PU-PEG). The resulting neural interfaces can per­form optogenetics and electrophysiology simultaneously. They can also be used to deliver cellular cargo with high viability. Upon exposure to water, PU-PEG cladding spon­taneously forms a hydrogel, which, in addition to enabling integration of modalities, can harbor small molecules and nanomaterials that can be released into local tissue follow­ing implantation. For example, the hydrogel of a SEED-­integrated neural interface can host a custom nanodroplet­-forming block polymer for delivery of hydrophobic small molecules in vitro and in vivo. SEED integration widens the chemical toolbox and expands the capabilities of multi­functional neural interfaces.