Norspermidine is a potent and non-bactericidal small-molecule inhibitor of biofilm growth.In this study,impacts ofnorspermidine on biofilm control and existing biofilm dispersal by a mixed culture from wastewater treatment systems were investigated.A surface-mediated releasing approach to preventing bacterial biofilm formation was established via encapsulating norspermidine into polyelectrolyte multilayer coatings.Results showed that the presence of norspermidine(500-1000 μM)in medium remarkably prevented biofilm formation.Norspermidine was also effective in disassembling pre-formed biofilms.Norspermidine containing multilayer coatings were successfully fabricated on glass slides via layer-by-layer deposition in polyethylenimine(PEI)and poly(acrylic acid)(PAA)solution.