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.