The synthesis of nanosized beads of superparamagnetic iron oxide nanoparticles coated with 3-(aminopropyl)triethoxysilane is reported in this paper. The resulting beads are agglomerates of SPIONs with an open fractal like structure. These beads have been examined by means of transmission electron microscopy (TEM), photon correlation spectroscopy (PCS), and attenuated total reflection Fourier transformation infrared spectroscopy (ATR-FTIR). The resulting beads with a size of 88 nm have been further biofunctionalized with avidin and biotinylated oligo(dT).