Small mesoporous silica nanoparticles as carriers for enhanced photodynamic therapy.

Small mesoporous silica nanoparticles (MSNs; ca. 37 nm in diameter) have a high loading capacity for a hydrophobic photosensitizer, SiPcCl(2) (82.6% in weight), and excellent endocytosis properties. As a result, the amount of SiPcCl(2) being delivered to cancer cells is increased by approximately two orders of magnitude compared to pure SiPcCl(2) at the same dosage, and the photodynamic therapy (PDT) efficiency is enhanced by over fourfold. Our method can be widely used to increase the dosage of hydrophobic anti-cancer drugs in cancer cells and therefore increase the cytotoxicity of the drugs.