Cobalt metallization of DNA: toward magnetic nanowires

Co nanoparticles have been assembled in situ on a template of double-stranded deoxyribonucleic acid (DNA) to form magnetic nanowires. DNA was immobilized on freshly cleaved mica or silanized glass and oriented by molecular combing. Pd(II) ions bound to DNA were reduced to zero-valence nanoclusters, which selectively catalysed deposition of Co(O) in a dimethylamine borane (DMAB)-based reducing bath. Co nanoclusters grew only where Pd nuclei were localized on the DNA template. Material characterization by UV-vis spectroscopy (UVS), atomic force microscopy (AFM), and energy dispersive x-ray (EDX) spectroscopy revealed that the fabrication process resulted in the formation of Co nanowires microns long and 10-20 nm thick.