Monolithic-to-focal evolving biointerfaces in tissue regeneration and bioelectronics

Material–biology interfaces are elemental in disease diagnosis and treatment. While monolithic biointerfaces are easier to implement, distributed and focal interfaces tend to be more dynamic and less invasive. Here, using naturally occurring precursors, we constructed a granule-releasing hydrogel platform that shows monolithic-to-focal evolving biointerfaces, thus expanding the forms, delivery methods and application domains of traditional monolithic or focal biointerfaces. Individual granules were embedded in a responsive hydrogel matrix and then converted into various macroscopic shapes such as bandages and bioelectronics–gel hybrids to enhance macroscopic manipulation. The granules can be released from the macroscopic shapes and establish focal bio-adhesions ex vivo and in vivo, for which molecular dynamics simulations reveal the adhesion mechanism. With the evolving design, we demonstrate that granule-releasing hydrogels effectively treat ulcerative colitis, heal skin wounds and reduce myocardial infarctions. Furthermore, we demonstrate improved device manipulation and bio-adhesion when granule-releasing hydrogels are incorporated into flexible cardiac electrophysiology mapping devices. This work presents an approach for building dynamic biointerfaces.