Tissue adhesives are a convenient alternative in lieu of the intricate surgical procedure of fastening sutures, staples, and similar fixtures to reconnect incisions and repair wounds. Among the widely accepted tissue adhesives are cyanoacrylates, owing to their unique reactivity, which drives the rapid polymerization from their monomeric liquid form to a solid adhesive film upon exposure to moisture or nucleophilic groups on tissues. Rigidity and brittleness, however, are infamous characteristics of cyanoacrylates, restricting their clinical use to low-tension tissues; hence, in several cases, these adhesives rely on external plasticizers for improved elongation at the expense of tensile strength or are used only in combination with sutures for additional mechanical support. To work eff...[ Read more ]

Tissue adhesives are a convenient alternative in lieu of the intricate surgical procedure of fastening sutures, staples, and similar fixtures to reconnect incisions and repair wounds. Among the widely accepted tissue adhesives are cyanoacrylates, owing to their unique reactivity, which drives the rapid polymerization from their monomeric liquid form to a solid adhesive film upon exposure to moisture or nucleophilic groups on tissues. Rigidity and brittleness, however, are infamous characteristics of cyanoacrylates, restricting their clinical use to low-tension tissues; hence, in several cases, these adhesives rely on external plasticizers for improved elongation at the expense of tensile strength or are used only in combination with sutures for additional mechanical support. To work effectively with elastic and dynamic tissues, the polymerized adhesive film must provide adequate flexibility and mechanical strength without affecting the natural function and movement of tissues.

This research presents a soft crosslinking agent based on polycaprolactone, which was incorporated to the adhesive film to impart stretchability. A multistep organic synthesis procedure was used to prepare the difunctional biscyanoacrylate ester of polycaprolactone diol, whose reactive end groups could facilitate the rapid crosslinking during adhesive setting. With an appropriately low crosslink density, the tissue adhesive formulation polymerized into a stretchable adhesive film having nearly thrice the fracture strain and half the tensile modulus than that obtainable with cyanoacrylate alone. The low proportion of crosslinking agent also allowed the integration thereof into the adhesive formulation without significant effect on polymerization time and composition stability. With these improvements, cyanoacrylate-based tissue adhesives can be used for a more diverse range of tissues, opening new opportunities for their applications in the biomedical field.