Abstract
Targeted drug delivery system (DDS) triggered by photo irradiation is described in this paper. A
mesoporous silica with a coumarin substituent grafted to the outlet region can store a drug molecule in its
mesopore, when the coumarin is dimerized by the irradiation of longer wavelength UV light to close the
gate of the mesopore. The drug molecule carried to target part can be released from the mesopore by the
cleavage of the coumarin dimer triggered by the irradiation of shorter wavelength UV light. The
continuous photo isomerization of azobenzene induced by the simultaneous irradiation of UV and visible
light promotes the release of a drug molecule from the mesopore. Double modified mesoporous silica
with the coumarin and the azobenzene substituents realizes an advanced targeted drug delivery. Using
this silica, both the release and the release rate of drug molecule in the mesopore can be controlled by
photo irradiations.
