Velcro-Inspired Poly(ethylene glycol) Gel (PEGgel) for Robust Interface Adhesion Between Hydrogel, Device, and Tissue.

Hydrogel bioadhesive is widely used in tissue engineering, flexible electronics, and other fields because of its mechanical softness and good biocompatibility. However, due to the differences in the mechanical strength of various biological tissues, the mechanical properties of specific hydrogel bioadhesives are difficult to easily adjust to adapt to different tissue strengths. Here, we propose a poly(methacrylamide-polyethylene glycol-N-hydroxysuccinimide ester-co-acrylic acid) PEGgel (MAP) bioadhesive based on the drying cross-linking mechanism and a polymer platform with PEG as the solvent. Compared with the reported hydrogel adhesives, MAP can adjust the tensile strength from 130 kPa to 1 MPa and the fracture strain from 149% to 2653% by modifying the molecular weight and proportion of solvent PEG. It also exhibits robust adhesion to tissues and various substrates, with its shear strength on pigskin and glass reaching 130 kPa and 6.8 MPa, respectively. The application of MAP for tendon healing and movement monitoring demonstrates the tough and compliant adhesion between hydrogel, device, and tissues. Combined with long-term storage capability, 3D-printable ability, self-healing ability, and biocompatibility, MAP represents a promising approach for the development of bioadhesives.