Development of a non-viral multifunctional envelope-type nano device by a novel lipid film hydration method.

The development of a multifunctional envelope-type nano device (MEND) for use in a non-viral gene delivery system using a novel lipid film hydration method is described. This packaging method involves three steps: (i) DNA condensation with a polycation, (ii) lipid film hydration for the electrostatic binding of the condensed DNA, and (iii) sonication to package the condensed DNA with lipids. For DNA condensation, the optimum ratio of DNA to poly-L-lysine (PLL) was determined by titrating DNA and PLL. The condensed DNA/PLL complex (DPC) was coated with a lipid bilayer by lipid film hydration followed by sonication, which was confirmed by sucrose density gradient centrifugation. Packaging of DPC with lipids increased the transfection activity 10-fold over that of DPC. MEND, having octaarginine on the envelope as a device for membrane penetration to enhance cellular uptake, showed a 1000-fold higher transfection activity than DPC. The MEND developed in this study represents a promising non-viral gene delivery system.