Broad spectrum antimicrobial activity of functionalized polyanilines

The antimicrobial properties of conductive functionalized polyanilines (fPANI) were investigated by exploring their interaction with bacterial cells. In sharp contrast to polyaniline (PANI), lower concentrations of fPANI were needed to strongly inhibit the growth of wild-type Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus, as well as several antibiotic-resistant clinical pathogens. To gain an insight into how fPANI have an impact on cellular physiology we used a whole genome expression study in the model E. coli MG1655 strain exposed to a representative fPANI. The expression levels of 218 (∼5.1%) genes changed significantly. Moreover, we found that certain oxidative damage-responsive genes were strongly induced, while genes potentially involved in energy metabolism and transport and in forming bacterial cell walls and stress-resistant cellular communities (biofilms) were repressed. Taken together, our results appear to indicate that the antimicrobial effects of fPANI, in part at least, might stem from their ability to target the operations of multiple and diverse cellular processes, and suggest that fPANI could be useful ingredients for biomaterials used in the development of food packaging and medical devices.