Mussel-inspired sandwich-like nanofibers/hydrogel composite with super adhesive, sustained drug release and anti-infection capacity.

• Silicate serves as a protectant to prevent the over-oxidation of PDA. • The tissue adhesive strength of the hydrogel is as high as 21.3 kPa. • The sandwich-like structure enables a sustained TH release. • Synergistic antibacterial effect of TH and CS of the composite. Multifunctional hydrogels with self-adhesive, self-healable, sustained drug release and anti-infection properties could be attractive candidates in biomedical and relevant applications. Here, inspired by mussel adhesive mechanism, we developed a series of novel super-adhesive hydrogels by incorporating polydopamine-intercalated silicate nanoflakes (PDA-Silicate) into chitosan/gelatin hydrogels. The intercalation of dopamine (DA) into silicate prevented its over-oxidization and preserved sufficient free catechol groups in the hydrogel. The hydrogel with optimal content of DA and silicate showed excellent adhesiveness to various substrates, with over 20 kPa of adhesive strength to porcine skin. To endow the hydrogel with antibacterial activity, the tetracycline hydrochloride (TH)-loaded electrospun nanofibers were inserted into the gel solution with optimal content of DA and silicate to form the sandwich-like nanofibers/hydrogel composite (NF-HG) in situ. The NF-HG displayed higher bacterial kill ratio than original hydrogel and the sustained released TH could provide long-term protection, minimizing drug toxicity related with burst release. Besides, NF-HG exhibited good cytocompatibility and favored cell proliferation. Taken together, this multifunctional hydrogel composite may inspire new aspects for potential biomedical materials. [ABSTRACT FROM AUTHOR]