Mechanized nanoparticles (MNPs) consisting of supramol. machines attached to the surface of mesoporous silica nanoparticles are designed to release encapsulated guest mols. controllably under pH activation. The mol. machines are comprised of cucurbituril (CB) rings that encircle tethered trisammonium stalks and can be tuned to respond under specific pH conditions through chem. modification of the stalks. Luminescence spectroscopy demonstrates that the MNPs are able to contain guest mols. within nanopores at neutral pH levels and then release them once the pH is lowered or raised.