Covalent immobilization of oligoDNA on the surface of magnetic nanoparticles and surface-enhanced Raman scattering study

The DNA magnetic nanoparticles are potentially useful in isolating and purifying DNA or RNA, directing-target-medicines, the development of DNA biosensors and biochips. Surface functionalized magnetic nanoparticles with monodispersed shape and size were prepared by coating nano-sized gamma-Fe2O3 with silica in reverse microemulsion, and then thiol-compounds were immobilized onto the magnetic nanoparticles. After immobilizing oligoDNA modified with thiol-disulfide on the surface of the fictionalized magnetic nanoparticles, we obtained DNA-magnetic nanoparticles. The efficiency of the single-linking probes loading at the surfaces of magnetic nanoparticles was examined via hybridization experiment. Surface-enhanced Raman scattering methods were also effectively applied to observing the immobilization and hybridization processes mentioned The results demonstrated oligoDNA being availably connected to the surface of the magnetic nanoparticles.