Silica-Based Nanoporous Materials

Mesoporous silica nanoparticles with a cubic (Ia3d) pore structure are derivatized with light-activated nanoimpellers to control the release of loaded guest molecules under external photo-control. The nanoimpellers consist of azobenzene derivatives that are attached to the interiors of the three-dimensional interconnected pores, and undergo photoisomerization that results in dynamic wagging motions of the unbound termini and drives the expulsion of molecules from the pores. Stimulated release experiments monitored by fluorescence spectroscopy demonstrate that the nanoimpeller-functionalized MCM-48 particles are able to trap and release both hydrophilic and hydrophobic cargo molecules under external photocontrol in aqueous, non-aqueous, and intracellular environments.