The effect of a branched architecture on the antimicrobial activity of poly(sulfone amines) and poly(sulfone amine)/silver nanocomposites

The antimicrobial activity of a series of cationic poly(sulfone amines) (PSAs) with different branched architectures and their polymer/silver (PSA/Ag) nanocomposites was investigated. PSAs with different branched architectures were synthesized through the polycondensation-addition reaction of divinylsulfone and 1-(2-aminoethyl) piperazine in mixed solvents. The silver ions were complexed to PSAs and then reduced to form PSA/Ag nanocomposites. The size of the silver nanoparticles (AgNPs) decreased with an increasing polymeric branched architecture. Both PSAs and PSA/Ag nanocomposites exhibited antimicrobial activity. Interestingly, the influence of the branched architecture on the antimicrobial activity was quite different for PSAs and PSA/Ag nanocomposites. For PSAs, the antimicrobial activity decreased with the branched architecture due to the reduced zeta-potential and low toxicity of the branched polymers. Owing to the high specific surface of small AgNPs, PSA/Ag nanocomposites exhibited an enhanced antimicrobial activity with an increasing polymeric branched architecture. These results demonstrate that the branched architecture of PSAs has an obvious influence on the antimicrobial activity of PSAs and PSA/Ag nanocomposites.