Conjugated Polyelectrolyte/Silver Bromide Nanocomposites: Highly Durable and Robust Antibacterial Materials

We report the in situ synthesis of silver bromide nanoparticles (AgBr NPs) in a cationic conjugated polyelectrolyte (CPE) matrix. It is interesting that the obtained CPE/AgBr nanocomposite materials exhibit robust and long-term antimicrobial activity against both Gram-negative bacteria and Gram-positive bacteria by producing a large amount of biologically active Ag⁺. Meanwhile, it is demonstrated that the antimicrobial activity of CPE/AgBr nanocomposites is also related to the size of the AgBr NPs. Smaller particles show a faster AgBr release rate and hence higher antimicrobial activity than big particles. However, the relatively large-sized nanocomposites are beneficial to obtain long-term antimicrobial activity by substantially producing bioactive Ag⁺. Consequently, the antimicrobial property of the CPE/AgBr nanocomposites can be manipulated by controlling the dimensions of embedded AgBr NPs. The CPE/AgBr nanocomposites can cause a rapid initial drop of bacterial counts in solution, which makes it a potential candidate for antimicrobial therapy in emergency cases. In addition, the sustained release of Ag⁺ from large-sized nanocomposites makes them suitable for long-term use.