Nanovalve activation by surface-attached photoacids

Proton transfer caused by excitation of a photoacid attached to the surface of a mesoporous silica nanoparticle activates a nanovalve and causes release of trapped molecules. The protonation of an aniline-based stalk releases a noncovalently bound cyclodextrin molecule that blocked a pore. The results show that pH-responsive molecular delivery systems can be externally controlled using light.