Modification of nanostructured calcium carbonate for efficient gene delivery

In this study, a facile method to modify nanostructured calcium carbonate (CaCO3) gene delivery systems by adding calcium phosphate (Cap) component was developed. CaCO3/CaP/DNA nanoparticles were prepared by the co-precipitation of Ca2+ ions with plasmid DNA in the presence of carbonate and phosphate ions. For comparison, CaCO3/DNA nanoparticles and Cap/DNA co-precipitates were also prepared. The effects of carbonate ion/phosphate ion (CO32-/PO43-) ratio on the particle size and gene delivery efficiency were investigated. With an appropriate CO32-/PO34- ratio, the co-existence of carbonate and phosphate ions could control the size of co-precipitates effectively, and CaCO3/CaP/DNA nanoparticles with a decreased size and improved stability could be obtained. The in vitro gene transfections mediated by different nanoparticles in 293T cells and HeLa cells were carried out, using pGL3-Luc as a reporter plasmid. The gene transfection efficiency of CaCO3/CaP/DNA nanoparticles could be significantly improved as compared with CaCO3/DNA nanoparticles and Cap/DNA co-precipitates. The confocal microscopy study indicated that the cellular uptake and nuclear localization of CaCO3/CaP/DNA nanoparticles were significantly enhanced as compared with unmodified CaCO3/DNA nanoparticles. (C) 2014 Elsevier B.V. All rights reserved.