High-efficiency gene delivery for expression in mammalian cells by nanoprecipitates of Ca-Mg phosphate.

Transfer of desirable genetic sequences into mammalian cells is an essential tool for analysis of gene structure, functions and regulation and industry-based production of therapeutically important proteins and pivotal for gene therapy and DNA vaccination strategies. Considering some severe limitations of viral systems including immunogenicity, carcinogenicity and so on, synthetic nonviral systems are highly desirable in the above applications. However, existing nonviral techniques are extremely inefficient compared to the viral ones. Therefore, we report here on the development of a highly efficient synthetic device for gene delivery and expression into mammalian cells, based on controllable growth of nanoapatite particles. Mg2+ incorporation into the apatite particles caused significant inhibition of particle growth, resulting in retention of nanosized particles which contributed remarkably to the cellular uptake of DNA and its subsequent expression (>10-fold) compared with classical calcium phosphate coprecipitation, one of the most widely used transfection methods.