Synthesis and characterization of a novel cationic polymer gene delivery vector

Non-viral vectors have been widely used in gene transfection. However, its drawbacks limit its applications. In this study, a novel cationic polymer was developed as a DNA condensing agent for systemic gene delivery. Its transfection efficiency, cytotoxicity, and biocompatibility were also evaluated. Sofast, novel cationic polymer of branched polyethlenimine, was constructed by chemical methods. Its diameter, zeta potential, nucleic acid binding ability, and anti-nuclease ability were detected by electron microscopy and gel electrophoresis. In vitro, the efficiency of transfection was measured by comparing it with other gene vectors in different cell lines. MTT assay was performed to determine cytotoxicity. The compatibility of Sofast gene vector in the serum and its stability were investigated. Mouse, guinea pig and rabbit were used to process the toxic, allergenic, and pyrogenic properties of the vector in vivo. The in vivo expression was performed in the guinea pig. The results from an in vitro assay proved that the Sofast gene vector had a higher transfection efficiency than other gene vectors in a variety of primary cell cultures and transformed cell lines. The cytotoxicity assay showed a lower cytotoxicity and the cellular survival rate was >90%. The Sofast gene vector possessed compatibility with the serum and was fit to be transported at normal temperature. The results from in vivo tests indicated that the Sofast gene vector had greatly lower cytotoxicity, better biocompatibility, and higher transfection efficiency compared with other gene vectors. Because the Sofast gene vector had higher transfection efficiency, lower cytotoxicity and better compatibility than other gene vectors, it could be used for gene transfection both in vitro and in vivo.