XANES of mammalian cells in the soft x-ray region for the basis of x-ray imaging

To image molecule or element distribution in a cell, XANES of such biomolecules in a cellular environment give direct information about photon energy choosing for imaging. This study describes XANES of dried Chinese hamster ovary cells in the pellet form at the N, O, P and S-K absorption edges. In addition, XANES of dried pellet of unclear and mitochondrial fraction were measured at the N and O-K edges. At the N-K edge XANES of cells had peaks at the identical energies of isolated DNA and historic, indicating that XANES peaks of biomolecules are insensitive to the cellular environment. The similar results were obtained for the cases of the P-K and S-K edges: XANES profile of cells at the P-K edge is likely to be a mixed pattern of DNA and related molecules including nucleotides, and the profile at the S-K edge could be explained by the superposition of those of SH and SS compounds. However, at the O-K edge, XANES of cells and nuclei exhibited the same peak slightly shifted to the higher energy compared with That in XANES of historic. This result indicates that for molecule or element imaging of a specimen, XANES should be measured under the specimen environment.