Synthesis of PVP-coated silver nanoparticles and their biological activity towards human mesenchymal stem cells

Silver nanoparticles were prepared by the polyol process, i.e. by the reduction of silver nitrate with ethylene glycol in the presence of polyvinylpyrrolidone. PVP. Thereby, the silver nanoparticles were colloidally stabilized by the polymer. The synthesis of nanoparticles of different size and shape (cubes, rods and spheres) was possible by changing the reaction conditions such as reagent ratio and temperature. The silver nanoparticles were characterized by dynamic light scattering (DLS), zeta-potential measurements. UV-spectroscopy, and scanning electron microscopy (SEM). The biological activity of spherical PVP-coated silver nanoparticles (about 100 nm diameter) was tested on human mesenchymal stem cells (hMSC) in comparison with equivalent amounts of silver ions (silver acetate). hMSC were treated with silver concentrations in the ran,e of 50 ng mL(-1) to 50 mu g mL(-1) for 7 days under cell Culture conditions. Cytotoxic cell reactions occurred at >= 2.5 mu g Ag mL(-1) for nanoparticles and >= 1 mu g Ag mL(-1) for silver acetate, indicating a critical role of the silver ions for toxic reactions.