EFFECT OF SIZE AND SERUM-PROTEINS ON TRANSFECTION EFFICIENCY OF POLY((2-DIMETHYLAMINO)ETHYL METHACRYLATE)-PLASMID NANOPARTICLES

Purpose. The aim of this study was to gain insight into the relation b etween the physical characteristics of particles formed by a plasmid a nd a synthetic cationic polymer (poly(2-dimethylamino)ethyl methacryla te, PDMAEMA) and their transfection efficiency. Methods. The PDMAEMA-p lasmid particles were characterized by dynamic light scattering (size) and electrophoretic mobility measurements (charge). The transfection efficiency was evaluated in cell culture (COS-7 cells) using a pCMV-la cZ plasmid coding for beta-galactosidase as a reporter gene. Results. It was shown that the optimal transfection efficiency was found at a P DMAEMA-plasmid ratio of 3 (w/w), yielding stable and rather homogeneou s particles (diameter 0.15 mu m) with a narrow size distribution and a slightly positive charge. Particles prepared at lower weight ratios, showed a reduced transfection efficiency and were unstable in time as demonstrated by DLS measurements. Like other cationic polymers, PDMAEM A is slightly cytotoxic. This activity was partially masked by complex ing the polymer with DNA. Interestingly, the transfection efficiency o f the particles was not affected by the presence of serum proteins. Co nclusions. PDMAEMA is an interesting vector for the design of in vivo and ex vivo gene transfection systems.