Hyperbranched In Situ Polymerized Cyanoacrylate Tissue Adhesives and Their Degradation

Cyanoacrylates are bioresorbable tissue adhesive materials whose ability to rapidly polymerize in situ into a strongly adhering film is suitable for closing wounds during emergencies. This polymerization method, which generates high-molecular-weight linear chains, has been applied and barely changed since the early clinical use of the adhesive because the requirement of rapid, straightforward in-situ polymerization for practicality restricted innovations involving the method and the material composition. Tissue adhesives, however, have been increasingly demanded to exhibit enhanced properties to cater to the needs of emerging trends in biomedical engineering. Our group has recently formulated a procedure to in situ polymerize cyanoacrylates into a branched adhesive film without sacrificing their practical features. Branching in the adhesive film, despite potentially introducing softness and enhancing mechanical properties, among others, can, however, influence the degradation of the adhesive film. The effects of branching on the rate of degradation and the composition of the degradation products were analysed by studying the degradation of branched polycyanoacrylates with varying degrees of branching and comparing them with conventionally polymerized linear equivalents. The degradation behavior of the adhesive is essential to avoid complications resulting not only from toxicity but also from the premature sloughing of the adhesive film from the wound surface.