pH-activated doxorubicin release from polyelectrolyte complex layer coated mesoporous silica nanoparticles

Mesoporous silica nanoparticles (MSN) functionalized with doxorubicin (Dox) and coated with a polyelectrolyte complex layer were tested in vitro to investigate drug release in cellular environment. The mesoporous silica nanoparticles inner surface was efficiently functionalized with the positively charged antitumoral drug doxorubicin. Polyelectrolyte layer complex was adsorbed on the outer surface of the MSN improving colloidal stability in biological media and forming an electrostatic barrier against the doxorubicin diffusion at biological pH. Dox-loaded silica nanoparticles showed a pH-dependent drug release behavior. Cell uptake of mesoporous silica nanoparticles and drug release dynamic were real-time monitored by laser scanning confocal microscopy. These results suggest that MSN could be exploited as smart carrier with pH-triggered drug releasing properties.