Facile hermetic TEM grid preparation for molecular imaging of hydrated biological samples at room temperature

• Published in: Nature communications 2023-09, Vol.14 (1), p.5641-10, Article 5641
• Main Authors: Kong, Lingli, Liu, Jianfang, Zhang, Meng, Lu, Zhuoyang, Xue, Han, Ren, Amy, Liu, Jiankang, Li, Jinping, Ling, Wai Li, Ren, Gang
• Format: Article
• Language: English
• Subjects: 101/28; 101/47; 13; 14/28; 49/62; 631/326/596/2557; 631/45/535/1258; 631/57/2265; 631/61/168; 631/80/2373; 82/47; BASIC BIOLOGICAL SCIENCES; Biological properties; Biological samples; Buffer solutions; Cellular imaging; Electron microscopy; Electrons; Environmental biotechnology; Humanities and Social Sciences; Image reconstruction; Liquid phases; Micrography; Microscopy; Molecular structure; multidisciplinary; Photomicrographs; Proteins; Questions; Room temperature; Science; Science (multidisciplinary); Single-molecule biophysics; Transmission electron microscopy; Viruses; Virus–host interactions
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-41266-x

Although structures of vitrified supramolecular complexes have been determined at near-atomic resolution, elucidating in situ molecular structure in living cells remains a challenge. Here, we report a straightforward liquid cell technique, originally developed for real-time visualization of dynamics at a liquid-gas interface using transmission electron microscopy, to image wet biological samples. Due to the scattering effects from the liquid phase, the micrographs display an amplitude contrast comparable to that observed in negatively stained samples. We succeed in resolving subunits within the protein complex GroEL imaged in a buffer solution at room temperature. Additionally, we capture various stages of virus cell entry, a process for which only sparse structural data exists due to their transient nature. To scrutinize the morphological details further, we used individual particle electron tomography for 3D reconstruction of each virus. These findings showcase this approach potential as an efficient, cost-effective complement to other microscopy technique in addressing biological questions at the molecular level. Electron microscopy of native hydrated biological samples close to physiological temperature is challenging. Here, authors encapsulate proteins and cells as an efficient, cost-effective complement to other microscopy technique in addressing biological questions at the molecular level.