Silica-magnetite nanoparticles: Synthesis, characterization and nucleic acid separation potential

Silica-coated magnetic nanoparticles can be utilized for the magnetic separation of nucleic acids, which is an important step in many clinical procedures. A series of silica-functionalized superparamagnetic iron oxide nanoparticles (SiO2@MNPs) was synthesized to efficiently separate nucleic acids for the sensitive detection of viral infections. Magnetite nanoparticles (MNPs) coated with different thicknesses of silica layer resulting from different ratios of tetraethylorthosilicate (TEOS) precursor to magnetite (TEOS/MNPs = 0.4, 1.0, 2.0, 3.0, 4.0, 5.0 ml/g) have been selected for characterization of their physico-chemical properties and biological activities. The SiO2@MNPs' morphology, size, magnetic and surface properties, cytotoxicity and nucleic acid binding propensity were determined to select the ones with the highest RNA separation potential. Our results showed that RNA-binding properties and magnetic separation efficiency are nanoparticle size-dependent. The highest binding and separation efficiencies were detected for the smaller SiO2@MNPs with TEOS/MNPs (v/w) ratios equal to 1.0 and 2.0. These nanoparticles are promising candidates for clinical application relevant to RNA viruses.