Synthesis and characterization of incorporating mussel mimetic moieties into photoactive hydrogel adhesive

Surgical adhesive is the optimal candidate for the replacement of traditional mechanical wound closure. In our paper, mussel adhesive proteins inspired hydrogel adhesive was prepared with 3, 4-dihydroxyphyenylanine acrylamide (DOPA-AA), poly (ethylene glycol) diacrylate (PEGDAA) and thiolated chitosan (CSS) by UV irradiation. DOPA-AA, containing catechol group and vinyl group, was successful synthesized and characterized by FTIR and ¹HNMR. The gelation time, equilibrium water content, degradation, materials properties and adhesive strength of the hydrogels were studied. We found that the gelation time was retarded and the materials mechanical strength was decreased because of the inhibitory effect of catechol group. Equilibrium water content was slightly affect by the increasing concentration of DOPA-AA (1-5%). Nevertheless, catechol group can remarkably improve the adhesive properties because of the complex and durable interactions of the hydrogel, especially, the interaction between the thiol group of CSS and catechol group of DOPA-AA, which also greatly slowed down the degradation of the adhesive hydrogels. CSS and DOPA-AA was introduced to ensure the adhesive properties, DOPA-AA lend the adhesive nature to hydrogel and CSS can protect the catechol group from oxidation and enhance durable adhesion. Moreover, cytotoxicity of the resulting hydrogels showed that the L929 cell viability was weaken, it mostly probably induced by the catechol oxidation.