Novel quaternary phosphonium-type cationic polyacrylamide and elucidation of dual-functional antibacterial/antiviral activity

A novel quaternary phosphonium-type cationic polyacrylamide (PPAD) was developed with a pendent butyltriphenylphosphonium bromide as the active moiety. A cationic monomer, diallyl dimethyl ammonium chloride (DADMAC), was introduced to impart positively charged groups to the backbone. The resulting cationic tripolymer was characterized with C-13-H-1 heteronuclear single quantum coherence (C-13-H-1 HSQC), static light scattering (SLS), apparent charge density measurement and UV spectrometry. The in vitro antibacterial activities of the synthesized polymers were investigated against Escherichia coli in terms of the minimum inhibitory concentration (MIC). To investigate the antibacterial mechanism, atomic force microscopy (AFM) technique was employed for tracking the dynamic process of killing bacteria. The antiviral activity of the copolymers was assessed via a plaque assay against non-enveloped adenovirus (ADV), and a corresponding model was established to reveal the mechanism of the action of PPAD on adenovirus. The results indicated that the incorporation of quaternary phosphonium salt (QPS) can render cationic PAM with antibacterial as well as antiviral activities, thus permitting the cationic tripolymer to be used as an antibacterial/antiviral intensifier, retention or filtration aid for various hygiene products or water clarification/disinfecting process.