Biocompatible,transparent, and water-resistant adhesive films with high mechanical stability derived from post-facile chemical cross-linking

Transparent surgical adhesives with excellent underwater adhesion and mechanical strength are strongly desirable for various biomedical applications such as wound closure and tissue healing. This is addressed in the present work by the development of biocompatible, transparent, and water-resistant adhesive films prepared from catechol-modified ε-poly(ʟ-lysine) and dopamine hydrochloride modified sodium hyaluronate layers successively applied using the layer-by-layer (LbL) assembly method. The LbL-assembled films are easily released from substrates via a mechanical exfoliation method with a blade to obtain free-standing multilayer films. The exceptional wet adhesion properties of the catechol groups yield films with excellent underwater adhesion strength. The underwater stability and mechanical strength of the free-standing multilayer films are improved via post-facile chemical cross-linking using biocompatible N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride. The post-treated free-standing multilayer films achieve a tensile strength of 0.36 ± 0.20 MPa and an elongation at break of 180.05% in water. The free-standing multilayer films exhibit a high optical transmittance greater than 55% in the visible region.