ABSTRACT
In the past 20 years, more than 400 clinical studies in gene therapy have been initiated.1 Gene therapy can be used to introduce exogenous genetic material (such as DNA, small interfering RNA [siRNA], and oligonucleotides) into cells or tissues to cure a disease or to improve associated symptoms. Gene therapy starts with the choice of a therapeutic gene, but most critical is the success in gene transfer to the target tissues. The delivery of naked nucleic acids (NAs) is not effective as they are degraded very quickly by nucleases and do not passively diffuse across plasma membranes due to their large hydrodynamic size and negative charge.
