Water-soluble PANI:PSS designed for spontaneous non-disruptive membrane penetration and direct intracellular photothermal damage on bacteria

The major challenge in the field of antibacterial agents is to overcome the low-permeability of bacteria cell membranes that protects the cells against diverse drugs.In this work,water-soluble polyaniline(PANI)-poly(p-styrenesulfonic acid)(PSS)(PANI:PSS)is found to spontaneously penetrate bacteria cellular membranes in a non-disruptive way,leaving no evidence of membrane poration/disturbance or cell death,thus avoiding side effects caused by cationic ammonia groups in traditional ammonia-containing antibacterial agents.For aqueous synthesis,which is important for biocompatibility,the polymer is synthesized via an enzyme-mimetic route relying on the catalysis of a nanozyme.Owing to its fluorescent properties,the localization of as-prepared PANI:PSS is determined by the confocal microscope,and the results confirm its rapid entry into bacteria.Under 808 nm near-infrared(NIR)irradiation,the internalized PANI:PSS generates local hyperthermia and destroys bacteria highly efficiently from inside the cells due to its excellent photothermal effects.Staphylococcus aureus(S.aureus),Methicillin-resistant Staphylococcus aureus(MRSA)and Escherichia coli(E.coli)could be effectively eliminated as well as the corresponding bacterial biofilms.Results of in vivo antibacterial experiments demonstrate excellent antibacterial activities of the water-soluble PANI:PSS without side effects.Therefore,the prepared water-soluble polymer in this study has great potential in the treatment of various bacterial infections.