Evolution of gold nanoparticles through Catalan, Archimedean, and Platonic solids

This paper reports the transformation of rhombic dodecahedral gold nanoparticles through two different pathways depending on the water content. The gold nanoparticles were prepared by reducing HAuCl ₄ with N,N-dimethylforamide in the presence of poly(vinyl pyrrolidone) and water. Not only the concentration of PVP but also the water content has a critical role in determining the shape transformation of the gold nanocrystals. At low water content the rhombic dodecahedron is transformed into a rhombicuboctahedron to a truncated octahedron and then to an octahedron, while at higher water content the rhombic dodecahedron is transformed into a rhombicuboctahedron and then to a cube or a truncated cube and then to a cuboctahedron and to a truncated octahedron. In addition, we demonstrated cell imaging by using the truncated octahedral, rhombic dodecahedral and octahedral gold nanoparticles as a contrast agent.