Porous chitosan adhesives with L-DOPA for enhanced photochemical tissue bonding

L-3,4-dihydroxyphenylalanine (L-DOPA) is a naturally occurring catechol that is known to increase the adhesive strength of various materials used for tissue repair. With the aim of fortifying a porous and erodible chitosan-based adhesive film, L-DOPA was incorporated in its fabrication for stronger photochemical tissue bonding (PTB), a repair technique that uses light and a photosensitiser to promote tissue adhesion. The results showed that L-DOPA did indeed increase the tissue bonding strength of the films when photoactivated by a green LED, with a maximum strength recorded of approximately 30 kPa, 1.4 times higher than in its absence. The addition of L-DOPA also did not appreciably change the swelling, mechanical and erodible properties of the film. This study showed that strong, porous and erodible adhesive films for PTB made from biocompatible materials can be obtained through a simple inclusion of a natural additive such as L-DOPA, which was simply mixed with chitosan without any chemical modifications. In vitro studies using human fibroblasts showed no negative effect on cell proliferation indicating that these films are biocompatible. The films are convenient for various surgical applications as they can provide strong tissue support and a microporous environment for cellular infusion without the use of sutures.