Mannosylated polyethylenimine coupled mesoporous silica nanoparticles for receptor-mediated gene delivery

Organic-inorganic nanohybrids have been studied for their use as non-viral transfection agents. The purpose of this study was to examine the ability of mesoporous silica nanoparticles (MSN) coupled with mannosylated polyethylenimine (MP) to transfect plasmid DNA in vitro. Although MSN is biocompatible and has low cytotoxicity, it is not easily transfected into a variety of cell types. To overcome this barrier, MP was coupled to MSN (abbreviated as MPS) to target macrophage cells with mannose receptors and enhance transfection efficiency. The DNA conveyance ability of MPS was examined by evaluating properties such as particle size, zeta potential, complex formation, protection of plasmid DNA against DNase-I, and the release of DNA upon cell entry. Particle sizes of the MPS/DNA complexes decreased with increasing weight ratio of MPS to DNA, while the zeta potential increased. Complete MPS/DNA complexes were formed at a weight ratio of five, and their resistance to DNase-I was evaluated. Cytotoxicity studies showed that MPS/DNA complexes resulted in a high percentage of cell viability, compared with PEI 25K as a vector. The transfection efficiency of MPS/DNA complexes was evaluated on Raw 264.7 and HeLa cell lines. It was found that MPS/DNA complexes showed enhanced transfection efficiency through receptor-mediated endocytosis via mannose receptors. These results indicate that MPS can be employed in the future as a potential gene carrier to antigen presenting cells. (C) 2008 Elsevier B.V. All rights reserved.