Antimicrobial sodium alginate dressing immobilized with polydopamine-silver composite nanospheres

To endow antibacterial activity and maintain good porosity, oxidized sodium alginate (OSA) sponge was functionalized via polydopamine/silver composite nanospheres (PDA/AgNSs). It is found that uniform PDA spheres (around 1.7 mu m) can be successfully coated on OSA sponge surface without compromise of the OSA sponge integrity and porosity using absolute ethanol as optimized solvent. Particularly, the newly-produced PDA spheres can crosslink with the OSA sponge via the Schiff-base condensation, leading to improved stability. On the other hands, those PDA spheres can be served as the active sites to realize the growth of silver nanoparticles (around 50-70 nm) on PDA spheres surface, leading to the formation of novel PDA/AgNSs. Further analysis indicates that our proposed OSA/PDA/AgNSs sponge shows high blood compatibility, low cell cytotoxicity, good hemostatic performance as well as superior inhibitory activity against P. aeruginosa, S. aureus and E. coli. In conclusions, our proposed strategy opens a new route for antimicrobial sodium alginate dressing development.