Synthesis and properties of biobased polyurethane tissue adhesives from bacterial polyester

Tissue adhesives provide an alternative method for painless wound closure compared to sutures and clips. However, the ideal tissue adhesive does not exist yet. Biocompatibility, short curing time, limited exothermic reaction and tailored properties to the final tissue are for instance key criteria to answer. In this study, biobased two-component polyurethane (PU) tissue adhesives were developed. They were composed of NCO-terminated prepolymers and a chain extender. The renewable prepolymers were synthesized from biopolyesters (oligomers obtained from poly(3-hydroxybutyrate)) and biobased or potentially biobased diisocyanates. Prepolymers chemical and physico-chemical properties were assessed, as well as their in vitro cytocompatibility. Then, PU bi-component adhesives bonding strength on muscle tissues and curing times were evaluated. Adhesion strength of 2–11 kPa were obtained, which are in the range of conventional fibrin adhesives. Curing times were in the range but slightly lower than other NCO-terminated PU adhesives found in the literature. Finally, cured prepolymer-chain extender systems were analyzed and exhibited a good in vitro cytocompatibility and low in vitro hydrolytic degradation, associated with a large range of physico-chemical and mechanical properties from hard and brittle to elastomeric behavior.