Poly(propylene fumarate)-Based Adhesives with a Transformable Adhesion Force for Suture-Free Fixation of Soft Tissue Wounds

The design of soft tissue adhesives with excellent adhesive performance has drawn much attention in biomedical applications for the suture-free fixation of soft tissue wounds. Poly(propylene fumarate) (PPF)-based materials exhibit excellent biocompatibility with nontoxic products and high mechanical strength and are widely used as bone repair materials. However, shortcomings, including low adhesive strength, low breathability, and poor hydrophobicity, as well as difficulty in detaching in vitro or degrading in vivo after wound tissue healing, limit the potential application of PPF-based materials in soft tissue adhesives. This study presented a biomimetic nucleobase-tackified strategy for designing PPF-based soft tissue adhesives, where adenine was diffusely distributed as a convex second phase in the PPF matrix and provided multipoint interactions with soft tissues. As a result, adenine increased both the lap shear strength by 200% (1.48 +/- 0.10 MPa) and the adhesive strength (1.70 +/- 0.08 MPa) by 45% in the early stage, and then with adenine degradation, the multipoint interactions disappeared and simultaneously achieved a removable adhesion function with tissue. Moreover, the formed microscale pores from the adenine degradation site also improved the maximum moisture vapor transmission rate by 238% and the hydrophilicity. This detachable adhesive strategy on PPF-based materials will significantly promote the next generation of soft tissue adhesives for biomedical applications.