Simultaneous synthesis of au and cu nanoparticles in pseudo-core-shell type arrangement facilitated by DMPG and 12-6-12 capping agents

A seed-growth method has been applied to synthesize the gold (Au) nanoparticles (NP) in the presence of 1,2-dimyristoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (sodium salt) (DMPG) and hexamethylene-1,6-bis(dodecyldimethylammonium bromide)(12-6-12) as capping agents at ambient conditions. The systematic addition of CuSO4 leads to anisotropic growth of Au NP at low CuSO4 concentration in the presence of DMPG while this was not observed in the case of 12-6-12 where mostly spherical Au NP were obtained. At high CuSO4 concentration, small Cu NP appeared which arranged themselves around large Au NP in a typical pseudo-core-shell type arrangement. This was achieved by the fusion of lipid bilayers of lipid-capped Au and Cu NP. The cause of anisotropic growth of Au NP in the presence of DMPG has been discussed on the basis of its poor capping ability in comparison to 12-6-12.