Mussel-inspired catechol-functionalization of degradable natural biomaterials such as gelatin has garnered significant interest as an approach to achieve bioadhesion for sutureless wound closure. However, conjugation capacity in standard coupling reactions… Click to show full abstract
Mussel-inspired catechol-functionalization of degradable natural biomaterials such as gelatin has garnered significant interest as an approach to achieve bioadhesion for sutureless wound closure. However, conjugation capacity in standard coupling reactions such as carbodiimide chemistry is limited by low yield and lack of abundant conjugation sites. Here, we propose a simple oxidative polymerization step before conjugation of catechol-carrying molecules (i.e., 3,4-dihydroxy-l-phenylalanine, l-DOPA) as a potential approach to amplify catechol function in bioadhesion of natural biomaterials, such as gelatin. Solutions of gelatin modified with poly(l-DOPA) moieties (GelDOPA) are characterized by increased viscosity, providing better control on double-curved tissue surfaces, and enabling fast thermal gelation in situ upon exposure to the tissue surface at room temperature compared to those of l-DOPA-conjugated gelatin. Physical hydrogels treated topically with low concentrations of NaIO4 solutions were crosslinked on-demand via through-thickness diffusion. Poly(l-DOPA) conjugates enhance crosslinking density compared to l-DOPA conjugated gelatin, resulting in lower swelling and enhanced cohesion in physiological conditions. Together with cohesion, more robust bioadhesive properties at body temperature were achieved by poly(l-DOPA) conjugates, exceeding those of commercial sealants. Further, poly(l-DOPA) motifs introduced photothermal responsive properties via near-infrared (NIR) irradiation for controlled drug release and potential applications in photothermal therapy. The above functionalities along with antibacterial activity render the proposed approach an effective biomaterial design strategy for wound closure applications. This article is protected by copyright. All rights reserved.
               
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