Fabrication of Biologically Functionalized, Electrically Conducting, and Aligned Magnetic Nanoparticles

Fabrication of nanomaterials in precisely 1-D or 2-D fashion is very difficult because the particles are very much active when their dimension is reduced and they tend to aggregate. Self-aggregation of nanoparticles can be avoided by their templating growth. We have biofunctionalized the magnetic nanoparticles (iron), aligned them in a chain-like fashion, made them electrically conducting all by using DNA as template. We coated the particles by gold as gold coating prevents them from oxidization. Average size of the synthesized DNA templated Fe_core -Au_shell particles are found to be ~ 14 nm from transmission electron microscopy (TEM) analysis. Fourier transformed infrared (FTIR) spectroscopic analysis was performed to investigate the bonding between metal ions and the DNA chain. Magnetic measurements of the particles show that the particles are ferromagnetic within 80 ≤ T ≤ 300 K but saturation magnetization (M_S) and coercivity (H_C) decreases with increasing temperature. These DNA templated, trifunctional Fe_core-Au_shell particles have great potential of finding applications in magnetically driven, spin-dependent devices as well as in hybrid devices.