University of Calabria, Department of Physics, 87036 Arcavata di Rende, Italy.
ESRF, The European Synchrotron, 38043 Grenoble, France.
Anal Chem. 2020 Apr 7;92(7):4814-4819. doi: 10.1021/acs.analchem.9b04096. Epub 2020 Mar 19.
X-ray microscopy is increasingly used in biology, but in most cases only in a qualitative way. We present here a 3D correlative cryo X-ray microscopy approach suited for the quantification of molar concentrations and structure in native samples at nanometer scale. The multimodal approach combines X-ray fluorescence and X-ray holographic nanotomography on "thick" frozen-hydrated cells. The quantitativeness of the X-ray fluorescence reconstruction is improved by estimating the self-attenuation from the 3D holography reconstruction. Applied to complex macrophage cells, we extract the quantification of major and minor elements heavier than phosphorus, as well as the density, in the different organelles. The intracellular landscape shows remarkable elemental differences. This novel analytical microscopy approach will be of particular interest to investigate complex biological and chemical systems in their native environment.
X 射线显微镜在生物学中应用越来越广泛，但在大多数情况下，只是定性地使用。我们在这里提出了一种 3D 相关的冷冻 X 射线显微镜方法，适用于在纳米尺度上对天然样品中的摩尔浓度和结构进行定量分析。这种多模态方法结合了 X 射线荧光和 X 射线全息纳米断层扫描技术，对“厚”的冷冻水合细胞进行分析。通过从 3D 全息重建中估计自衰减，可以提高 X 射线荧光重建的定量准确性。应用于复杂的巨噬细胞，我们提取了磷以外的主要和次要元素以及不同细胞器的密度的定量信息。细胞内的景观显示出显著的元素差异。这种新的分析显微镜方法将特别有助于在其天然环境中研究复杂的生物和化学系统。
