DNA-templated assemblies of nickel hexacyanoferrate crystals

We report here the synthesis of nickel hexacyanoferrate (NiHCF) crystals using calf thymus DNA (CT-DNA) as a template. The double-stranded CT-DNA has been used as a template to self-assemble NiHCF crystals and to produce aggregates having different morphologies at different temperatures. The guided self-assembly behavior of DNA was studied at different temperatures by scanning electron microscopy. The cube-shaped crystals of NiHCF with an average diameter of 400 nm are observed along the DNA framework at room temperature; however, at higher temperatures, the morphology of NiHCF changed from open tubular to dendrimer. The intermediate temperatures show long chains (up to many micrometers) and spherical structures of NiHCF crystals. The micrometer long DNA template plays a key role in the formation of extended arrays of NiHCF crystals, suggesting that the templating action is retained even at the higher temperatures.