A dual-enhancement antibacterial strategy for hierarchically functionalized surfaces with photodynamic and antifouling performance

Bacterial adhesion always occurs on various plastic surfaces in air filtration, water treatment, food processing, medical industry and many other industries. In this work, to prevent bacterial adhesion, we proposed a facile and universal antibacterial strategy to construct hierarchically structured surfaces with photodynamic and antifouling performance. Polyvinyl chloride (PVC) was taken as a representative of widely used plastics for functionalization. Hydrophobic pentamethine carbocyanine photosensitizers (PCPs) with quaternary ammonium groups (CD6 and CD10) were synthesized as bactericidal agents. The PVC surfaces were functionalized with CD6 or CD10 by hydrophobic interaction (PCD). Subsequently, a kind of super-hydrophilic polymer, poly (3-[dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]azaniumyl]propane-1-sulfonate, PDMAPS) was grafted from PCD by surface-initiated atom transfer radical polymerization to form the hierarchical structure (PCDD). PCDD exhibited a high efficiency to prevent bacteria adhesion and showed effective photodynamic bactericidal properties under 808 nm near infrared irradiation. PCDD also showed a good antifouling performance by the hydrophilicity of PDMAPS. The biocompatibility of PCDD was also proven by cytotoxicity test. The present work provides a facile and promising approach to develop antibacterial surfaces of plastics for various application fields that are exposed to bacteria.