A novel gene carrier based on amino-modified silica nanoparticles

Uniform-sized amino-modified silica nanopar-ticles have been prepared by the controlled synchronous hydrolysis of tetraethoxysilane and N-(?amimoethyl)-- aminopropyltriethoxysilane in water nanodroplet of the wa-ter-in-oil microemulsion. These nanoparticles display posi-tive charge potential at definited pH. This is due to the pres-ence of amino groups on the surface of the nanoparticles. Nanoparticles-plasmid DNA complexes can easily form through electrostatical binding between the positive charges of the amino-modified silica nanoparticles and the negative charges of the plasmid DNA. The complexes can be also dis-sociated under alkaline pH or high ionic strength conditions. And enzymatic digestion of the plasmid DNA is almost in-hibited by these nanoparticles complexes. A novel non-viral gene carrier based on the amino-modified silica nanoparti-cles is proposed under the combination of nanotechnology, biotechnology and gene engineering technology. The plasmid DNA can successfully cross various systemic barriers to COS-7 cells as well as mediate high expression of Green Fluorescence Protein (GFP) gene in cells by use of this novel gene carrier.