ABSTRACT
Gene therapy is the treatment of human disorders by the introduction of genetic material into specic target cells of a patient, in which production of the encoded protein occurs (Corsi et al. 2003). A wide variety of vectors that are capable of delivering therapeutic genes into the desired target cells have been studied (Nishikawa and Hashida 2002). Gene therapy is currently being applied to many different health problems such as cancer, AIDS, and cardiovascular diseases (Ozbas-Turan et al. 2003). Several trials employing gene therapy protocols have already been successfully completed in patients with cystic brosis (Gill et al. 1997, Porteous et al. 1997) and adenosine deaminase deciency (Bordignon et al. 1995). Many researches are working in the eld of gene delivery to develop ideal gene delivery carriers. There are several systems that can be used to transfer foreign genetic material into the human body. Gene carriers should possess certain ideal properties. The DNA to be transferred must escape the processes that affect the disposition of macromolecules. These processes include the interaction with blood components, vascular endothelial cells, and uptake by the reticuloendothelial system. Furthermore, the degradation of therapeutic DNA by serum nucleases is also a potential obstacle for functional delivery to the target cell (Quong and Neufeld 1998). Thus, an ideal gene-delivering carrier should transport genetic materials without any toxicity and immune responses (Smith et al. 1997). It must be capable of protecting the DNA until it reaches its target. To do so, the system must be small enough to allow internalization into cells and passage to the nucleus, it must have exible tropisms for applicability in a range of disease targets, and it must be capable of escaping endosome-lysosome processing and of following endocytosis (Mansouri et al. 2004).
