Immobilization of DNA on Fe nanoparticles and their hybridization to functionalized surface

Magnetic Fe nanoparticles were fabricated using a magnetron–sputtering-based gas-phase condensation method, and they have an average size of 20 nm. The Fe nanoparticles were modified by 3-aminopropyltriethoxy silane, and were subsequently activated by glutaraldehyde, and then amino modified DNA oligomers were loaded on glutaraldehyde activated Fe nanoparticles. Their surface was investigated and confirmed by X-ray photoelectron spectroscopy (XPS). The concentrations of 3-aminopropyltriethoxy silane and glutaraldehyde play important roles for subsequent DNA immobilization, and their optimal concentrations are 0.5 vol% and 5.0 wt%, respectively. The loading level of DNA oligomers on Fe nanoparticles was quantitatively evaluated. We found that the presence of sodium dodecyl sulfate (SDS) surfactant can significantly increase the DNA loading level and the highest loading value reached to 47 mol DNA/mol Fe nanoparticles. The DNA–Fe complexes can be selectively hybridized to the DNA functionalized surface.