An indicator-guided photo-controlled drug delivery system based on mesoporous silica/gold nanocomposites

A mesoporous silica/gold （MSN/Au） nanocomposite was designed for photo- controlled drug delivery targeted specifically at tumor cells. The MSN/Au nanocomposite was composed of MSN-based drug carriers and gold nanoparticle （AuNP）-based indicators. While the MSN-based drug carrier was a mesoporous silica nanoparticle immobilized with photo-switchable azobenzene （Azo） moieties, the AuNP-based indicator was a fluorescence-quenched AuNP modified with a matrix metalloproteinase （MMP） substrate and poly（ethylene glycol）. The two kinds of nanoparticles were connected by an α,β cyclodextrin （α,β CD） dimer ＂bridge.＂ In vitro studies demonstrated that the nanocomposite specifically interacted with tumor sites overexpressing MMP-2, which enabled guidance of the subsequent UV light irradiation for releasing entrapped drugs. Through integration of the AuNP-based indicator and the MSN-based drug carrier, the MSN/Au nanocomposite could precisely localize the released drug to tumor sites, thereby significantly improving therapeutic efficacy.