PREPARATION, CHARACTERIZATION AND CYTOTOXICITY OF METHYLMETHACRYLATE COPOLYMER NANOPARTICLES WITH A PERMANENT POSITIVE SURFACE-CHARGE

Methylmethacrylate copolymer nanoparticles containing different cation ic comonomers such as N-trimethylammoniumethylmethacrylate (TMAEMC), N -dimethylammoniumethylmethacrylate (DMAEMC), N-trimethylammoniumpropyl methylacrylamide (MAPTAC) or the anionic comonomer sulfopropylmethacry late (SPM), respectively, were prepared by free radical polymerization . Particle size was determined by photon correlation spectroscopy (PCS ), transmission and scanning electron microscopy (TEM, SEM), and surfa ce charge by microelectrophoresis. Pure poly(methylmethacrylate) nanop articles served as control. Depending on the method, mean diameters of permanently positively-charged nanoparticles MMA-TMAEMC and MMA-MAPTA C were 243 or 207 nm (PCS), 161 or 201 nm (TEM), and 158 or 197 nm (SE M), respectively. Zeta potential examined in demineralized water or Na Cl solution was +63.4 or +32.1 mV for MMA-TMAEMC nanoparticles and +49 .2 or +32.0 mV for MMA-MAPTAC nanoparticles, respectively. Cytotoxicit y of nanoparticles was determined by MTT assay in three different cell cultures including human foreskin fibroblasts (HFF) and two monkey ki dney cell lines MA-104 and Vero. Cell viability profiles of TMAEMC and MAPTAC containing nanoparticles were different, showing IC50 values f or MMA-TMAEMC nanoparticles of 189.6 +/- 11.4 mu g/ml (MA-104), 110.9 +/- 3.1 mu g/ml (Vero) and 27.2 +/- 4.0 mu g/ml (HFF). Cell viability at maximum concentration of 500 mu g/ml MMA-MAPTAC nanoparticles was 9 8.3% (Vero), 85.7% (MA-104), or 94.0% (HFF), respectively. (C) 1997 El sevier Science B.V.