The dual-stimulated release of size-selected cargos from cyclodextrin-covered mesoporous silica nanoparticles

A drug delivery system of dual-stimulated release of size-selected cargos from beta-cyclodextrin-covered mesoporous silica nanoparticles was prepared. Calcein loaded mesoporous silica nanoparticles (MSN) were capped by beta-cyclodextrin (beta-CD) through photocleavable moieties to control its release. Then the small size cargo p-coumaric acid (CA) was loaded. The cavity of beta-cyclodextrin was blocked by ferrocene through the host-guest interaction between the ferrocene and beta-cyclodextrin. The small cargo can be released by the escape of ferrocene under +1.5 V electro-stimuli. Calcein molecules could not pass through the cavity of the beta-cyclodextrin due to its bigger size. The calcein was released from the MSN after the detachment of the beta-cyclodextrin cap from the MSN surface with UV irradiation. Fluorescence spectra demonstrate that different sized cargoes were released successfully step by step under external UV-light and electro stimuli respectively.