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  4. TECHNIQUE ADVANCES AND APPLICATIONS OF CRYO-ELECTRON-MICROSCOPY FOR THE STUDY OF VITRIFIED BIOLOGICAL SYSTEMS

TECHNIQUE ADVANCES AND APPLICATIONS OF CRYO-ELECTRON-MICROSCOPY FOR THE STUDY OF VITRIFIED BIOLOGICAL SYSTEMS

File(s)
Yu_cornellgrad_0058F_13717.pdf (40.73 MB)
Permanent Link(s)
https://doi.org/10.7298/y44z-ma46
https://hdl.handle.net/1813/114816
Collections
Cornell Theses and Dissertations
Author
Yu, Yue
Abstract

Cryo-electron microscopy (cryo-EM) is a powerful technique extensively uti- lized for studying biological systems. It allows for high-resolution structural de- termination of macromolecules and visualization of cellular structures in their near-native environment.This thesis starts with a concise overview of the fundamental principles and applications of selective cryo-EM techniques with conventional transmission electron microscopy (TEM), such as single particle analysis (cryo-SPA), electron tomography (cryo-ET), and focused-ion-beam milling (cryo-FIB). Subsequently, applications of scanning-TEM (STEM) in vitrified hydrated biological systems are introduced, along with the progress made in four-dimensional STEM (4D- STEM) techniques. The challenges encountered in imaging thick biological specimens using conventional TEM techniques are highlighted, along with the limited applica- bility of conventional STEM for high-resolution structural determination due to collection efficiency limitations. To address these challenges, a 4D-STEM technique, tilt-corrected bright-field STEM (tcBF-STEM) is introduced, aiming to provide advantages for imaging thick dose-sensitive specimens by optimiz- ing the collection efficiency of coherent BF-STEM images. The implementation of tcBF-STEM with a pixelated detector optimized for STEM is demonstrated, along with the extraction of probe aberration information using tcBF imaging. Notably, tcBF-STEM enables the retrieval of information beyond the real-space scanning Nyquist limit, effectively mitigating the effects of specimen motion in cryo-EM experiments with a single tilt direction. The results of applying tcBF- STEM to imaging vitrified biological specimens, including vitrified apoferritin protein and E. coli bacteria, are presented. The potential of tcBF-STEM and its limitations are discussed at the end.

Description
116 pages
Date Issued
2023-08
Keywords
apoferritin
•
cryogenic electron microscopy
•
E.coli
•
four-dimensional STEM
•
low-dose TEM imaging
•
vitrified biological specimens
Committee Chair
Kourkoutis, Lena
Committee Member
Paszek, Matthew
Lambert, Guillaume
Degree Discipline
Applied Physics
Degree Name
Ph. D., Applied Physics
Degree Level
Doctor of Philosophy
Type
dissertation or thesis
Link(s) to Catalog Record
https://newcatalog.library.cornell.edu/catalog/16219259

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