A serum-tolerant hydroxyl-modified polyethylenimine as versatile carriers of pDNA/siRNA.

The polyethylenimine (PEI) derivatives (PTn) are prepared by treating PEI25k with Tris(hydroxymethyl) acrylamidomethane via the Michael addition. These PTns can effectively condense nucleic acids into nanosized particles with positive surface charges. The PTns show lower cytotoxicity and better serum-resistant capacity than PEI25k. Specially, the transfection efficiency of PT26/DNA is 29-fold higher than that of PEI25k in HeLa cells in serum-containing medium. The PTn/siRNA complexes show superior knockdown effect in CT26 cells in serum-containing medium. In addition, flow cytometry analysis shows that the PTns can efficiently mediate the entry of nucleic acids into the cell. Thus, PTns are potentially applicable as non-viral carriers of nucleic acids and warrant further development for use in gene therapy.