Abstract: In invention concerns elastin-like polymer (ELP) delivery compositions and methods for the use thereof. In some aspects ELP compositions may be used to deliver therapeutic nucleic acids, polypeptides of small molecules. In some aspects, in vivo delivery with ELP compositions can directed to specific target sites by the application of local hyperthermia therapy. Compositions and methods for ELP gene therapy are provided.

Abstract: Linear polyethylenimine was modified with sterols, such as cholesterol, in three different geometries: linear shaped (L), T-shaped (T), and a combined linear- and T-shaped (LT), to result in linear polyethylenimine-sterol conjugates. These conjugates were mixed with nucleic acids to form complexes for delivery of the nucleic acids into cells. Mammalian cells transfected with these complexes showed protein expression levels higher than linear polyethylenimine alone, and twice that of branched polyethylenimine, but without any significant loss in cell viability. Methods of making these compositions and methods of using them for gene delivery are also described.