Rapid one-pot fabrication of magnetic calcium phosphate nanoparticles immobilizing DNA and iron oxide nanocrystals using injection solutions for magnetofection and magnetic targeting

Abstract

This is the first report on rapid (5–30 min) one-pot fabrication of magnetic calcium phosphate (CaP) nanoparticles (NPs) co-immobilizing DNA and iron oxide (IO) nanocrystals with high immobilization efficiencies (DNA (∼90%) and IO (∼70%)). NPs were fabricated via coprecipitation under clean bench in supersaturated CaP solutions using DNA, IO-based MRI contrast agent, and infusion quality source solutions (even the water used was of injectable quality) that ensured high safety level of the fabrication process and product. Prepared DNA-IO-CaP NPs exhibited strong magnetic property allowing their noncontact manipulation by external magnet. These NPs were smaller than 500 nm, had relatively large negative zeta potential showing stable dispersion without any additional surfactant, and exhibited no significant cytotoxicity under the tested transfection conditions. The IO content of these NPs was significantly varied and by adjusting the initial IO concentration, DNA-IO-CaP NPs with gene delivery capability to CHO-K1 cells as high as that of the IO-free DNA-CaP NPs without external magnetic field were prepared. Fabricated DNA-IO-CaP NPs showed significantly improved gene delivery capability under external magnetic field compared to the IO-free DNA-CaP NPs. Thus, the present coprecipitation process can be considered as a novel technique to fabricate multifunctional CaP-based NPs to achieve magnetofection and targeted delivery.