Abstract: Disclosed are highly compliant bioelectronic neural interface devices with hydrogel adhesion. Example devices include adhesion-promoting functional groups that facilitate enhanced electrical contact with the nerve without the need for continuous application of pressure. A transfer process may be used to fabricate the device using a sacrificial material (e.g., polyacrylic acid (PAA)) that has tunable solubility in aqueous media, helping avoid the need for harsher release chemicals that may affect the properties of the hydrogel. The transfer process also helps achieve electrode contacts that are flush with a surface of the device and facilitate more intimate contact with the nerve. A gradual change in Young's modulus from a stiff contact pad region to a more compliant electrode contact region may be achieved via a varied amount of an epoxy-based material (such as SU-8 ) and with silicone-based material (such as polydimethylsiloxane (PDMS)) to encapsulate the device cable.