Cucurbit[8]uril-mediated supramolecular photoswitching for self-preservation of mesoporous silica nanoparticle delivery system.

In this study, a novel UV-responsive drug carrier based on mesoporous silica nanoparticles (MSNs) has been designed. A 'self' peptide was introduced onto the MSN surface through a supramolecular photoswitchable heteroternary complexation of cucurbit[8]uril, azobenzene and 4,4'-dipyridyl derivative. The light-induced isomerization of azobenzene contributed to the formation of intelligent cucurbit[8]uril based self-preserving MSNs (CSMSNs). In vitro studies demonstrated that the CSMSNs were effectively shielded against macrophages by the peptide protective layer. Doxorubicin hydrochloride (DOX·HCl) could be well encapsulated in the CSMSNs and exhibit low toxicity without UV-irradiation. After reaching the tumor tissue, the peptide camouflage was removed upon UV-irradiation, which enabled the target ligand mediated cell uptake of the drug carrier and the accelerated drug release.