Revealing the structural, coordinative, and oxidative states of iron in asbestos fibers and bodies from human lungs

Toxicity/carcinogenicity of Fe-bearing mineral fibers has been proposed to be driven by a complex and subtle relation between the total Fe amount and the structural, coordinative, and oxidative states of the Fe sites. However, the specific conditions that make Fe sites able to induce free radical generation are not clear yet. Here, we propose to perform a complete structural characterization of Fe in Asbestos Fibers (AF) and Asbestos Bodies (AB, i.e. asbestos fibers with the Fe-coating they develop in biological tissues) retrieved from lung tissues with an innovative, non-invasive method. The local and medium range structural environment of Fe bulk sites will be revealed by Fe K-edge X-ray Absorption Spectroscopy (XAS) and X-ray Pair Distribution Function (XPDF), respectively. The proposed combined XAS-XPDF experiment will complement single crystal nano-X-ray Diffraction measurements on single AF and AB to be performed at ID11@ESRF, for which beamtime has already been granted.