Multifunctional envelope-type nano device (MEND) as a non-viral gene delivery system

In this review, we describe a key role of octaarginine (R8) in developing our new concept of “Programmed Packaging”, by which we succeeded in creating a multifunctional envelope-type nano device (MEND) as a non-viral gene-delivery system. This concept can be applied not only to nuclear targeting of plasmid DNA (pDNA) but also to cytosolic delivery of functional nucleic acids such as oligonucleotides or siRNA. This concept has been extended to other organelles such as mitochondria as a foundation for innovative nanomedicine. Finally, we discuss the rate-limiting step in gene delivery by comparing non-viral and viral gene delivery systems, which clearly indicates the importance of nuclear disposition of pDNA for efficient transfection.