A new gene delivery system based on controlled release technology.

The recent rapid development of molecular biology together with the steady progress of genome projects has given us some essential and revolutionary informations of gene to elucidate all the biological phenomena at the molecular level. Under these circumstances, gene transfection has become a fundamental technology indispensable to the basic research of medicine and biology. On the other hand, the technology of gene transfection is also important for gene therapy of several diseases. Some human gene therapies have been performed with a plasmid DNA alone or virus vectors but are clinically limited by the poor gene expression of plasmid DNA and the adverse effects of virus itself, such as immunogenicity and toxicity or the possible mutagenesis of cells transfected. Therefore, several non-viral vectors of synthetic materials have been explored to enhance the transfection efficiency of gene into mammalian cells both in vitro and in vivo. In this paper, the researches about non-viral vectors and recent research trials about the controlled release of plasmid DNA are briefly reviewed to emphasize the significance of gene delivery technology in basic biology and medicine as well as clinical medicine. A new system of gene release based on biodegradable hydrogel is introduced.