Composite copolymer hybrid silver nanoparticles: preparation and characterization of antibacterial activity and cytotoxicity

With the increasing concern over drug-resistant bacterial infections, in particular hospital-acquired infections, there is an urgent need to develop effective and safe antibacterial agents. Herein, a study aiming at developing a good antibacterial agent with high antibacterial activity and low cytotoxicity to promote public health is reported. Composite copolymer hybrid silver nanoparticles (AgNPs) were synthesized via the reduction of NaBH4 in the presence of copolymers and AgNO3. The composite copolymers containing 2-(dimethylamino) ethyl methacrylate (DMAEMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMA) segments were prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization, and then the copolymers were quaternized to increase AgNPs adhesion to bacterial membranes through electrostatic interactions. The copolymer hybrid AgNPs showed high antibacterial activity against P. aeruginosa (Gram-negative bacteria) and S. aureus (Gram-positive bacteria), which could inhibit bacterial proliferation even if the concentration was 8 mu g mL(-1). Furthermore, copolymer hybrid AgNPs had negligible haemolysis and low cytotoxicity. The nanoparticles destroyed the bacterial membrane irreversibly and then caused the release of cytoplasmic constituents and cell death finally. These results suggest that copolymer hybrid AgNPs have potential use as antibacterial agents in clinical applications.