Synthesis of monodispersed ORMOSIL nanoparticles and conjugation with DNA for gene therapy

Nanomedicine is an emerging new field combining nanotechnology and medicine. Silica nanoparticles are chemical and biologically inert, optically transparent and can be doped with imaging agents and/or functionalized to promote its conjugation with different therapeutic molecules. Silica nanoparticles can be engineered to improve diagnosis, treatment and follow-up of diseases. A combination of diagnosis devices and therapeutics (theranostics) would be beneficial for patients. In this work, ORMOSIL nanoparticles as non-viral vectors for gene delivery were prepared via a modified Stober sol-gel process directly with 3-aminopropyltriethoxysilane and tetraethylorthosilicate as precursors. Dynamic light scattering, transmission electron microscopy and Fourier transformed infrared spectroscopy were used to characterizing the hybrid nanospheres. Synthesis has been optimized and monodisperse spherical nanoparticles with desired size have been obtained. Nanoparticle-DNA complexes were successfully obtained at different ratios (nanoparticle/pDNA) and confirmed by agarose gel electrophoresis and ethidium bromide exclusion test.