Seeing cells in 3D: Cryo-soft X-ray tomography in the laboratory
Date: Wednesday, December 6, 2023
Time: 11 a.m. – 1 p.m. ET
Location: 12-0168 (MIT.nano basement)
Lunch will be provided to registered participants, sponsored by SiriusXT
Abstract
Analysis of three-dimensional biological cell samples is critical for understanding the mechanisms of disease and for the development of novel therapeutics. Soft X-ray tomography (SXT) is the unique technology that can image whole intact cells in 3D under normal and pathological conditions without labelling or fixation, at high throughput and with a spatial resolution of approximately 50 nm [1-4]. The 3D image is obtained from a series of 2D projection images; essentially a medical CT applied at the nanoscale. The microscope uses X-rays in the water window, a region of the spectrum extending from the K-absorption edge of carbon, 282 eV (λ = 4.4 nm), to the K-edge of oxygen, 533 eV (λ = 2.3 nm). Hence, water is transparent to these X-rays while organic molecules are absorbing, meaning the image contrast is entirely native. This reduces the sample preparation to just cryo-fixation. Whole cell information, such as the size, shape, and 3D distribution of organelles (mitochondria, endosomes etc.) or nanoparticles can be obtained out-of-the-box.
SiriusXT has developed a laboratory-scale microscope [5, 6] that will facilitate the widespread use of this powerful technique and encourage the development of novel correlative and multimodal imaging workflows that can benefit from cryo-SXT. An integrated fluorescence microscope allows correlative studies. Additionally, SXT images could be combined with either room temperature TEM (following freeze substitution) or cryo-ET (following cryo-FIB milling to a lamella) to permit the imaging of the same sample across multiple scales and complexities.
During this seminar, SiriusXT will present its new technology, including an overview of the instrument, sample preparation and data handling workflows, sample carriers, correlative workflow developments, and recent imaging data. Finally, scientific applications that could benefit from this novel imaging technique will be discussed.
References
[1] M Harkiolaki et al., Emerging Topics in Life Science 2 (2018), p. 18. doi: 10.1042/ETLS20170086
[2] J Guo and CA Larabell, Current Opinion in Structural Biology 58 (2019), p. 324. doi: 10.1016/J.SBI.2019.06.012
[3] G Schneider et al., Nature Methods 7 (2010), p. 985. doi: 10.1038/NMETH.1533
[4] FJ Chichón et al., Journal of Structural Biology 177 (2012), p. 202. doi:10.1016/J.JSB.2011.12.001
[5] K Fahy et al., JPhys Photonics 3 (2021), doi: https://doi.org/10.1088/2515-7647/abfc5a
[6] https://cocid.eu/