A novel Janus nanomachine based on mesoporous silica nanoparticles anisotropically modified with PAMAM dendrimers for enzyme-controlled drug delivery.

A masking/toposelective modification approach was employed to prepare a new organic-inorganic Janus nanomaterial by attaching ethylenediamine core polyamidoamine G-4.5 dendrimers to a defined face of mesoporous silica nanoparticles. The anisotropic colloid was then sequentially functionalized on the mesoporous face with (3-isocyanatopropyl)triethoxysilane, 1-(4-aminophenyl)-2-phenylethane-1,2-dione and β-cyclodextrin to assemble a novel HO-sensitive gating mechanism. The Janus nanomachine was finally constructed by immobilizing glucose oxidase on the dendrimeric face. The smart nanodevice released the encapsulated payload in the presence of HO and glucose, and was successfully evaluated for the enzyme-controlled delivery of the antitumoral drug doxorubicin into HeLa cancer cells.