Hydrogel tapes for fault-tolerant strong wet adhesion

Abstract

Fast and strong bio-adhesives are in high demand for many biomedical applications, including closing wounds in surgeries, fixing implantable devices, and haemostasis. However, most strong bio-adhesives rely on the instant formation of irreversible covalent crosslinks to provide strong surface binding. Repositioning misplaced adhesives during surgical operations may cause severe secondary damage to tissues. Here, we report hydrogel tapes that can form strong physical interactions with tissues in seconds and gradually form covalent bonds in hours. This timescale-dependent adhesion mechanism allows instant and robust wet adhesion to be combined with fault-tolerant convenient surgical operations. Specifically, inspired by the catechol chemistry discovered in mussel foot proteins, we develop an electrical oxidation approach to controllably oxidize catechol to catecholquinone, which reacts slowly with amino groups on the tissue surface. We demonstrate that the tapes show fast and reversible adhesion at the initial stage and ultrastrong adhesion after the formation of covalent linkages over hours for various tissues and electronic devices. Given that the hydrogel tapes are biocompatible, easy to use, and robust for bio-adhesion, we anticipate that they may find broad biomedical and clinical applications.

Recent advances of mussel-inspired materials in osteoarthritis therapy

“…Owing to the Michael reaction between the catechol and quinone groups on GeP@PDA and HA-DA and the amino or thiol groups on the protein, the hydrogel has excellent tissue adhesion, can be well integrated with neural tissue, and promotes nerve repair. Cao et al [62] connected dopa to the carboxyl group of alginate in the presence of NHS and EDC, and used ascorbic acid method and degassing method to prevent the oxidation of dopa, from which alginate-dopa was prepared. The mass percentage of dopa in alginate-dopa was about 21% measured by ultraviolet spectrophotometer (figure 8(A)).…”