Tuesday, April 23, 2013

Tailor-made Au@Ag core–shell nanoparticle 2D arrays on protein-coated graphene oxide with assembly enhanced antibacterial activity

Huiqiao Wang, Jinbin Liu, Xuan Wu, Zhonghua Tong and Zhaoxiang Deng



Water-dispersible two-dimensional (2D) assemblies of Au@Ag core–shell nanoparticles are obtained through a highly selective electroless silver deposition on pre-assembled gold nanoparticles on bovine serum albumin (BSA)-coated graphene oxide (BSA-GO). While neither BSA-GO nor AuNP-decorated BSA-GO shows any antibacterial ability, the silver-coated GO@Au nanosheets (namely GO@Au@Ag) exhibit an enhanced antibacterial activity against Gram-negative Escherichia coli ( E. coli ) bacteria, superior to unassembled Au@Ag nanoparticles and even ionic Ag. Such an improvement may be attributed to the increased local concentration of silver nanoparticles around a bacterium and a polyvalent interaction with the bacterial surface. In addition, the colloidal stability of this novel nano-antimicrobial against the formation of random nanoparticle aggregates guarantees a minimized activity loss of the Au@Ag nanoparticles. The antibacterial efficacy of GO@Au@Ag is less sensitive to the ...



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