A novel visible light responsive nanosystem for cancer treatment.

A novel singlet-oxygen sensitive drug delivery nanocarrier able to release its cargo after exposure to visible (Vis) light from a common lamp is presented. This nanodevice is based on mesoporous silica nanoparticles (MSN) decorated with porphyrin-caps grafted via reactive oxygen species (ROS)-cleavable linkages. In the presence of Vis light porphyrin-nanocaps produce singlet oxygen molecules that break the sensitive-linker, which triggers pore uncapping and therefore allows the release of the entrapped cargo (topotecan, TOP). This new system takes advantage of the non-toxicity and greater penetration capacity of Vis radiation and a double antitumor effect due to the drug release and the ROS production. In vitro tests with HOS osteosarcoma cancer cells reveal that TOP is able to be released in a controlled fashion inside the tumor cells. This research work constitutes a proof of concept that opens up promising expectations in the search for new alternatives for the treatment of cancer.