Augmentation of postswelling surgical sealant potential of adhesive hydrogels

Two‐component hydrogels formed with star polyethylene glycol amine and linear dextran aldehyde polymers (PEG:dextran) show promise as tissue‐specific surgical sealants. However, there is a significant loss of adhesion strength to soft tissues following PEG:dextran swelling, which may limit material ability to appose disjoined tissues and prevent leakage from surgical sites. We covalently incorporated the modified amino acid L ‐3,4‐dihydroxyphenylalanine ( L ‐DOPA) into PEG:dextran to enhance postswelling sealant performance. L‐DOPA is an essential component of marine animal adhesive plaques and has been used to confer wet adhesion in synthetic materials. As both PEG:dextran cohesion and adhesion are mediated by aldehyde‐amine interactions, L ‐DOPA side‐groups make it a potent network modulator with potential to affect multiple material properties. Following 1‐h submersion in aqueous media, PEG:dextran doped with 3 m M L ‐DOPA/M aldehyde on average swelled 50.3% less, had 287.4% greater stiffness, and had 53.6% greater functional adhesion strength compared to the neat hydrogel. Increased concentrations of L ‐DOPA up to 11 m M L ‐DOPA/M aldehyde similarly curtailed swelling and mitigated property loss with hydration, but sacrificed initial functional adhesion strength, material modulus, and biocompatibility. Taken together, these data support tailored L ‐DOPA conjugation as a promising approach to enhance the clinical performance of PEG:dextran sealants. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.