Localized oxidative killing of tumor cells by glassy iron nanoparticles (Nanowerk News) Amorphous iron nanoparticles have a specific toxicity in tumor cells. In the journal Angewandte Chemie ("Synthesis of Iron Nanometallic Glasses and Their Application in Cancer Therapy by a Localized Fenton Reaction"), Chinese scientists describe their design and synthesis of a special amorphous state of nanoparticulate iron, which can locally release reactive iron species in the acidic and hydrogen peroxide rich environment of cancer cells, providing new possibilities for theranostics and chemodynamic therapies.

A Trojan Horse for Cancer Cells - Localized oxidative killing of tumor cells by glassy iron nanoparticles. (© Wiley-VCH)

Cancer cells are characterized by their relatively acidic cell environment and their production of significant amounts of hydrogen peroxide compared to healthy cells. Some chemodynamic approaches for cancer treatment thus employ the Fenton reaction, that is, iron ions reacting with the hydrogen peroxide to produce reactive oxygen species (ROS), which in turn can damage and destroy the cancer cells. However, the transport of iron ions to the target cells is problematic, and crystalline iron nanoparticles are not as effective.

Therefore, Jianlin Shi and Wenbo Bu and their groups at Shanghai Institute of Ceramics, in collaboration with Fudan University of Shanghai, China, have now prepared iron nanoparticles in an amorphous, glassy state. "Interestingly, the amorphous iron(0) nanoparticles present several unique physicochemical properties," the scientists write, and: "The results confirm that the amorphous iron nanoparticles, hydrogen peroxide, and acidic conditions act synergistically as nanotechnology to kill cancer cells."

In addition to their potential as drugs, other advantages are a good contrast for magnetic resonance imaging and the possibility of magnetic targeting. "Ideally, a perfect carrier should release its cargo at once when it is transferred from neutral to mildly acidic conditions, such as those in the tumor microenvironment," the authors write. Using magnetic resonance imaging, they proved by in vitro and in vivo tests that the anticipated mechanism was working.