A novel temperature-responsive polymer as a gene vector.

A temperature-responsive polymer poly{2-(dimethylamino)ethyl methacrylate-co-[cis-butenedioic anhydride-poly[(N-isopropylacrylamide)-co-(butyl methacrylate)]]} (PDMNIB) was synthesized by free radical polymerization. The polymer had a significant temperature-responsive behavior with a lower critical solution temperature (LCST) at 20 degrees C. Gel retardation assay showed that PDMNIB could efficiently interact with DNA. Dynamic light scattering (DLS) and zeta potential measurement indicated that the average sizes and the surface electric charges of the PDMNIB/DNA complexes could be changed by temperature. Due to the thermosensitive interaction between PDMNIB and DNA, the gene transfection efficiency of PDMNIB could be improved by temperature.