In that nanotechnology holds great promise for the development of targeted, localized delivery of anticancer drugs, in which only cancer cells are affected, Fuyuhiko Tamanoi, from the University of California/Los Angeles (UCLA; California, USA), and colleagues have developed mesoporous silica nanoparticles (MSNs) with the capacity to store and deliver chemotherapeutic drugs in vivo and effectively suppress tumors in mice. The researchers also showed that MSNs accumulate almost exclusively in tumors after administration and that the nanoparticles are excreted from the body after they have delivered their chemotherapeutic drugs.  Finding that MSNs circulate in the bloodstream for extended periods of time and accumulate predominantly in tumors, the team also revealed that tumor accumulation could be further improved by attaching a targeting moiety to MSNs.  The researchers conclude that: “These results indicate that [mesoporous silica nanoparticles] are biocompatible, preferentially accumulate in tumors, and effectively deliver drugs to the tumors and suppress tumor growth.”