Purpose Nucleic acid-based therapies are a promising therapeutic tool. The major obstacle in their clinical translation is their efficient delivery to the desired tissue. We developed a novel nanosized delivery system composed of conjugates of α-tocopherol, polyethyleneimine, and polyethylene glycol (TPP) to deliver nucleic acids. Methods We synthesized a panel of TPP molecules using different molecular weights of PEG and PEI and analyzed with various analytical approaches. The optimized version of TPP (TPP111 - the 1:1:1 molecular ratio) was self-assembled in water to produce nanostructures and then evaluated in diversified in vitro and in vivo studies. Results Through a panel of synthesized molecules, TPP111 conjugate components self-assembled in water, forming globular shaped nanostructures of ~90 nm, with high nucleic acid entrapment efficiency. The polymer had low cytotoxicity in vitro and protected nucleic acids from nucleases. Using a luciferase-expressing plasmid, TPP111-plasmid nano-complexes were rapidly up-taken by cancer cells in vitro and induced strong transfection, comparable to PEI. Colocalization of the nano-complexes and endosomes/lysosomes suggested an endosome-mediated uptake. Using a subcutaneous tumor model, intravenously injected nano-complexes preferentially accumulated to the tumor area over 24 h. Conclusion These results indicate that we successfully synthesized the TPP111 nanocarrier system, which can deliver nucleic acids in vitro and in vivo and merits further evaluation.
