Reichardt M, Neuhaus C, Nicolas JD, Bernhardt M, Toischer K, Salditt T
Biophys J. 2020 Oct 6;119(7):1309-1323.
We present a multi-scale imaging approach to characterize the structure of isolated adult murine cardiomyocytes based on a combination of full-field three-dimensional (3d) coherent x-ray imaging and scanning x-ray diffraction. Using these modalities, we probe the structure from the molecular to the cellular scale. Holographic projection images on freeze-dried cells have been recorded using highly coherent and divergent x-ray waveguide radiation. Phase retrieval and tomographic reconstruction then yield the 3d electron density distribution with a voxel size below 50 nm. In the reconstruction volume, myofibrils,sarcomeric organisation and mitochondria can be visualized and quantified within a single cell without sectioning. Next, we use micro-focusing optics by compound refractive lenses to probe the diffraction signal of the acto-myosin lattice. Comparison between recordings of chemically fixed and untreated, living cells indicate that the characteristic lattice distances shrink by approximately 10% upon fixation.