Involvement of Lysosomal Exocytosis in the Excretion of Mesoporous Silica Nanoparticles and Enhancement of the Drug Delivery Effect by Exocytosis Inhibition

Advances in nanotechnology have resulted in the development of new nanoparticles that have the potential to revolutionize medicine. Many nanomaterials have been engineered that promise to enhance drug delivery efficacy to target tissues, reduce side effects, and provide a delivery vehicle for hydrophobic anticancer drugs or imaging agents. Among these materials, MCM-41 mesoporous silica has received much attention because of its large surface area, large internal pore volume, tunable pore size and good chemical and thermal stability.[1–6] Mesoporous silica nanoparticles (MSNs) are taken up into cancer cells by energy-dependent endocytosisand the majority of them co-localize with the endo/lysosomal compartments.[7–11] We as well as others have shown that MSNs can serve as efficient drug delivery vehicles and imaging vectors.[1–3,12–24] Their biocompatibility, biodistribution and their efficacy to inhibit tumor growth have been demonstrated in animal studies.[25–28]