DNA-templated magnetic nanowires with different compositions: fabrication and analysis.

The structure and magnetic properties of different types of templated wires are compared in this study. A long DNA molecule was used to guide the assembly of pyrrolidinone-capped Fe2O3 and CoFe2O3 particles as well as polylysine-coated gold nanoparticles. The resulting DNA-templated wires were stretched onto silicon oxide surfaces using a receding meniscus procedure. The coated, stretched, and surface-bound wires were characterized using atomic force microscopy (AFM), magnetic force microscopy (MFM), and spectroscopic methods. The results with respect to the wire properties were correlated with those determined from the bulk properties of the nanoparticles and with the properties of the bulk DNA. The MFM measurements allowed us to visualize the formation of domains along the wires as well as qualitatively compare the magnetic properties of each templated structure.