**1. Introduction**

198 Non-Viral Gene Therapy

Yoon, H. A., Aleyas, A. G., George, J. A., Park, S. O., Han, Y. W., Lee, J. H., Cho, J. G., and

*Microbiol Immunol*, 50(2), 83-92.

Eo, S. K. (2006). "Cytokine GM-CSF genetic adjuvant facilitates prophylactic DNA vaccine against pseudorabies virus through enhanced immune responses."

> Gene therapy and treatment with siRNA hold potential to treat a wide variety of different diseases. Genetic material is not usually stable and is generally hydrolyzed following intravascular administration. This makes the delivery of genes somewhat problematic since intact genetic material must usually be delivered intracellularly for therapeutic effect. For gene therapy, in most cases the gene construct must reach the cellular intranuclear subcompartment in order to elicit the desired biological effect. Viruses have evolved to deliver DNA and RNA to cells but viral vector-based gene therapy has been associated with effects inherent in biological systems (Marshall, Muruve, Thomas). Non-viral based systems afford the potential to deliver genetic materials without the adverse biological effects of viral-based systems. In most cases, however, non-viral based gene delivery systems have been less effective than viral based systems, yielding lower levels of gene expression (Litzinger). Microbubbles, e.g. acoustically active carriers, in concert with ultrasound (Unger, Zhou) may afford potential for highly effective site directed gene therapy and delivery of other genetic materials such as siRNA (Zhigang).
