Nanoparticles deliver combination cargos directly to cancer targets
Successful treatment for cancer requires efficient delivery of potent drugs to kill tumor cells with minimal side effects. In a study* published online in the journal Nature Materials in April, investigators constructed synthetic “protocells” that were used to kill liver tumor cells without adversely affecting healthy cells. Protocells are made by enclosing highly porous silica nanoparticles, 100-150 nanometers in diameter, with a lipid bilayer thus mimicking a cell membrane. The bilayer includes protein ligands that specifically target tumor cells, and the porous core is preloaded with anti-cancer drugs. Upon binding to its target, the protocell enters the tumor cell and releases its cargo, thereby killing the cancerous cell. Protocells can carry high concentrations and different combinations of cargo, such as drugs, small interfering RNAs, and other toxins. The cargo capacity and time course of release can be controlled by changing the pore size and chemistry of the silica core, but the protocell is designed to release the cargo only upon entry into the target cell. In the future, protocells may be designed to efficiently and effectively target and kill various types of cancer cells, depending on the cargo loaded inside and the targeting molecules used on the surface of the protocell. However, before using in human studies, protocells will first need to be tested in animal models.
The investigators of this study were supported in part by the National Center for Design of Biomimetic Nanoconductors, which is one of eight centers of the NIH Nanomedicine Program, funded by the NIH Common Fund.
*Ashley CE, Carnes EC, Phillips GK, Padilla D, Durfee PN, Brown PA, Hanna TN, Liu J, Phillips B, Carter MB, Carroll NJ, Jiang X, Dunphy DR, Willman CL, Petsev DN, Evans DG, Parikh AN, Chackerian B, Wharton W, Peabody DS, Brinker CJ (2011). The targeted delivery of multicomponent cargos to cancer cells by nanoporous particle-supported lipid bilayers. Nature Materials 10: 389-397.