Visualization of a Mammalian Mitochondrion by Coherent X-ray Diffractive Imaging

Abstract

We report a three dimensional (3D) quantitative visualization of a mammalian mitochondrion by coherent x-ray diffractive imaging (CXDI) using synchrotron radiation. The internal structures of a mitochondrion from a mouse embryonic fibroblast cell line (NIH3T3) were visualized by tomographic imaging at approximately 60 nm resolution without the need for sectioning or staining. The overall structure consisted of a high electron density region, composed of the outer and inner membranes and the cristae cluster, which enclosed the lower density mitochondrial matrix. The average mass density of the mitochondrion was about 1.36 g/cm3. Sectioned images of the cristae reveal that they have neither a baffle nor septa shape but were instead irregular. In addition, a high resolution, about 14 nm, 2D projection image was captured of a similar mitochondrion with the aid of strongly scattering Au reference objects. Obtaining 3D images at this improved resolution will allow CXDI to be an effective and nondestructive method for investigating the innate structure of mitochondria and other important life supporting organelles.

Three-dimensional imaging of mitochondrial cristae complexity using cryo-soft X-ray tomography

“…On the other hand, the use of X-ray based imaging can provide information about thick and large area biological samples and under cryogenic conditions to avoid the radiation damage, for instance the modalities of X-ptychography of vegetal tissues 18 and soft X-rays of whole cells 19 . Mitochondria has been already explored by X-ray imaging to be identified in the cellular context of wild-type single cells 19,20 , in cancer cells 21,22 and isolated from the cells aiming to unveil its internal structure 23 . However, there are no reports of X-ray imaging-based analysis focusing on extracting 3D morphological and quantitative information about the OMM and IMM organization.…”

Coherent diffractive imaging of microtubules using an X-ray laser

“…This concept was first validated using micro-fabricated 2D samples at a soft X-ray laser 21 and now provides the basis for serial femtosecond crystallography of micro-crystalline protein samples to high-resolution 22,23 . Coherent X-ray diffraction image reconstructions from data collected at XFELs have been reported for viruses in projection 24,25 and in 3D 26,27 as well as for carboxysomes 28 and mitochondria 29 . Despite these advances, the resolution of the image reconstructions is limited to a few tens of nanometers 30 .…”

Laser-induced metastable mixed phase of AuNi nanoparticles: a coherent X-ray diffraction imaging study

“…Interpolation was applied to the y and z axes to make the voxels cubic, and the final voxel size was (11.3 nm) 3 . The incident X-ray flux was used to determine the electron density values of the reconstructed 3D image (Miao et al, 2003;Kim et al, 2017b). In order to evaluate the incident X-ray flux, we monitored the current of a pin diode frequently and found it to be in the range 21.5 nA to 22.5 nA (22 nA AE 0.5 nA) when we measured the 0 data set.…”