Novel magnetite-silica nanocomposite (Fe3O4-SBA-15) particles for DNA binding and gene delivery aided by a magnet array.

Novel magnetite-silica nanocomposite particles were prepared using SBA-15 nanoporous silica as template. Magnetite nanoparticles were impregnated into the nanopore array of the silica template through thermal decomposition of iron(III) acetylacetonate, Fe(AcAc)3 at 200 degrees C. These composite particles were characterized using TEM, XRD and SQUID magnetometry. The TEM images showed that the size of composite particles was around 500 nm and the particles retained the nanoporous array of SBA-15. The formation of magnetite nanoparticles was confirmed by the powder XRD study. These composite particles also exhibited ferrimagnetic properties. By coating with short chain polyethyleneimine (PEI), these particles are capable of binding DNA molecules for gene delivery and transfection. With an external magnetic field, the transfection efficiency was shown to have an increase of around 15%. The results indicated that these composite nanoparticles may be further developed as a new tool for nanomagnetic gene transfection.