Star-shaped polycaprolactone bearing mussel-inspired catechol end-groups as a promising bio-adhesive

The catechol groups in mussel adhesive proteins exhibit excellent adhesion property to the skin and tissue surfaces. Inspired by catechol groups, the aim of this study is to synthesize the star-shaped polycaprolactone bio-adhesive bearing catechol end-groups (s-PCL 19 -CA 9 ). Firstly, star-shaped polycaprolactone was synthesized through ring-opening polymerization of caprolactone monomers initiated by β-cyclodextrin, and then the s-PCL 19 -CA 9 was obtained through end-group functionalization using succinic anhydride and dopamine. The structure of s-PCL 19 -CA 9 was characterized by 1 H NMR, FTIR, and static light scattering. Adhesive strength measurements demonstrate that the incorporation of multifunctional catechol groups endows the crosslinked s-PCL 19 -CA 9 with an excellent adhesion property (102 ± 10 kPa). The swelling ratio of crosslinked s-PCL 19 -CA 9 is as low as 3.4 ± 0.2% owing to the hydrophobicity of PCL and the crosslinking structures. Besides, the cytotoxicity studies show that s-PCL 19 -CA 9 is noncytotoxic. The TGA measurements indicate that s-PCL 19 -CA 9 possesses a good thermal stability. Therefore, this work provides a new way for developing multifunctional bio-adhesives with excellent adhesion property and low swelling ratio.